Facies analysis and sequence stratigraphic framework of upper Campanian strata (Neslen and Mount Garfield formations, Bluecastle Tongue of the Castlegate sandstone, and Mancos shale), Eastern Book cliffs, Colorado and Utah

USGS Publications Warehouse

Kirschbaum, Mark A.; Hettinger, Robert D.

2004-01-01

Facies and sequence-stratigraphic analysis identifies six high-resolution sequences within upper Campanian strata across about 120 miles of the Book Cliffs in western Colorado and eastern Utah. The six sequences are named after prominent sandstone units and include, in ascending order, upper Sego sequence, Neslen sequence, Corcoran sequence, Buck Canyon/lower Cozzette sequence, upper Cozzette sequence, and Cozzette/Rollins sequence. A seventh sequence, the Bluecastle sequence, is present in the extreme western part of the study area. Facies analysis documents deepening- and shallowing- upward successions, parasequence stacking patterns, downlap in subsurface cross sections, facies dislocations, basinward shifts in facies, and truncation of strata.All six sequences display major incision into shoreface deposits of the Sego Sandstone and sandstones of the Corcoran and Cozzette Members of the Mount Garfield Formation. The incised surfaces represent sequence-boundary unconformities that allowed bypass of sediment to lowstand shorelines that are either attached to the older highstand shorelines or are detached from the older highstand shorelines and located southeast of the main study area. The sequence boundary unconformities represent valley incisions that were cut during successive lowstands of relative sea level. The overlying valley-fill deposits generally consist of tidally influenced strata deposited during an overall base level rise. Transgressive surfaces can be traced or projected over, or locally into, estuarine deposits above and landward of their associated shoreface deposits. Maximum flooding surfaces can be traced or projected landward from offshore strata into, or above, coastal-plain deposits. With the exception of the Cozzette/Rollins sequence, the majority of coal-bearing coastal-plain strata was deposited before maximum flooding and is therefore within the transgressive systems tracts. Maximum flooding was followed by strong progradation of parasequences and low preservation potential of coastal-plain strata within the highstand systems tract. The large incised valleys, lack of transgressive retrogradational parasequences, strong progradational nature of highstand parasequences, and low preservation of coastal-plain strata in the highstand systems tracts argue for relatively low accommodation space during deposition of the Sego, Corcoran, and Cozzette sequences. The Buck Canyon/Cozzette and Cozzette/Rollins sequences contrast with other sequences in that the preservation of retrogradational parasequences and the development of large estuaries coincident with maximum flooding indicate a relative increase in accommodation space during deposition of these strata. Following maximum flooding, the Buck Canyon/Cozzette sequence follows the pattern of the other sequences, but the Cozzette/Rollins sequence exhibits a contrasting offlapping pattern with development of offshore clinoforms that downlap and eventually parallel its maximum flooding surface. This highstand systems tract preserves a thick coal-bearing section where the Rollins Sandstone Member of the Mount Garfield Formation parasequences prograde out of the study area, stepping up as much as 800 ft stratigraphically over a distance of about 90 miles. This progradational stacking pattern indicates a higher accommodation space and increased sedimentation rate compared to the previous sequences.

Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs (Annex 1). Annual report, February 1, 1991--January 31, 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watney, W.L.

1992-08-01

Interdisciplinary studies of the Upper Pennsylvanian Lansing and Kansas City groups have been undertaken in order to improve the geologic characterization of petroleum reservoirs and to develop a quantitative understanding of the processes responsible for formation of associated depositional sequences. To this end, concepts and methods of sequence stratigraphy are being used to define and interpret the three-dimensional depositional framework of the Kansas City Group. The investigation includes characterization of reservoir rocks in oil fields in western Kansas, description of analog equivalents in near-surface and surface sites in southeastern Kansas, and construction of regional structural and stratigraphic framework to linkmore » the site specific studies. Geologic inverse and simulation models are being developed to integrate quantitative estimates of controls on sedimentation to produce reconstructions of reservoir-bearing strata in an attempt to enhance our ability to predict reservoir characteristics.« less

Depositional sequence analysis and sedimentologic modeling for improved prediction of Pennsylvanian reservoirs (Annex 1)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watney, W.L.

1992-01-01

Interdisciplinary studies of the Upper Pennsylvanian Lansing and Kansas City groups have been undertaken in order to improve the geologic characterization of petroleum reservoirs and to develop a quantitative understanding of the processes responsible for formation of associated depositional sequences. To this end, concepts and methods of sequence stratigraphy are being used to define and interpret the three-dimensional depositional framework of the Kansas City Group. The investigation includes characterization of reservoir rocks in oil fields in western Kansas, description of analog equivalents in near-surface and surface sites in southeastern Kansas, and construction of regional structural and stratigraphic framework to linkmore » the site specific studies. Geologic inverse and simulation models are being developed to integrate quantitative estimates of controls on sedimentation to produce reconstructions of reservoir-bearing strata in an attempt to enhance our ability to predict reservoir characteristics.« less

Seismic stratigraphy, tectonics and depositional history in the Halk el Menzel region, NE Tunisia

NASA Astrophysics Data System (ADS)

Sebei, Kawthar; Inoubli, Mohamed Hédi; Boussiga, Haïfa; Tlig, Said; Alouani, Rabah; Boujamaoui, Mustapha

2007-01-01

In the Halk el Menzel area, the proximal- to pelagic platform transition and related tectonic events during the Upper Cretaceous-Lower Miocene have not been taken into adequate consideration. The integrated interpretation of outcrop and subsurface data help define a seismic stratigraphic model and clarify the geodynamic evolution of the Halk el Menzel block. The sedimentary column comprises marls and limestones of the Campanian to Upper Eocene, overlain by Oligocene to Lower Miocene aged siliciclastics and carbonates. Well to well correlations show sedimentary sequences vary considerably in lithofacies and thicknesses over short distances with remarkable gaps. The comparison of sedimentary sequences cut by borehole and seismic stratigraphic modelling as well help define ten third order depositional sequences (S1-S10). Sequences S1 through S6 (Campanian-Paleocene) are mainly characterized by oblique to sigmoid configurations with prograding sedimentary structures, whereas, sequences S7-S10 (Ypresian to Middle Miocene) are organized in shallow water deposits with marked clinoform ramp geometry. Sedimentary discontinuities developed at sequence boundaries are thought to indicate widespread fall in relative sea level. Angular unconformities record a transpressive tectonic regime that operated from the Campanian to Upper Eocene. The geometry of sequences with reduced thicknesses, differential dipping of internal seismic reflections and associated normal faulting located westerly in the area, draw attention to a depositional sedimentary system developed on a gentle slope evolving from a tectonically driven steepening towards the Northwest. The seismic profiles help delimit normal faulting control environments of deposition. In contrast, reef build-ups in the Eastern parts occupy paleohighs NE-SW in strike with bordering Upper Maastrichtian-Ypresian seismic facies onlapping Upper Cretaceous counterparts. During the Middle-Upper Eocene, transpressive stress caused reactivation of faults from normal to reverse play. This has culminated in propagation folds located to the west; whereas, the eastern part of the block has suffered progressive subsidence. Transgressive carbonate depositional sequences have predominated during the Middle Miocene and have sealed pre-existing tectonic structures.

Sequence stratigraphic principles applied to the Miocene Hawthorn Group, west-central Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norton, V.L.; Randazzo, A.F.

1993-03-01

Sequence boundaries for the Miocene Hawthorn Group in the ROMP 20 drill core from Osprey, Sarasota County, FL were generally delineated by lithologic variations recognized from core slabs, thin section analysis, and geophysical logs. At least six depositional sequences representing third order sea level fluctuations were identified. Depositional environments were determined on the basis of the characteristic lithologic constituents including rip-up clasts, pellets, fossils, laminations, burrow, degree of induration, and grain sorting. The sequence boundaries appear to have formed when the rate of the eustatic fall exceeded basin subsidence rates producing a relative sea level fall at a depositional shorelinemore » break. As a result of the basinward facies shift associated with this sequence type, peritidal facies may directly overlie deeper water facies. Subaerial exposure and erosion can be expected. The sequence of facies representing progressively deeper water depositional environments, followed by a progressive shallowing, were present between bounding surfaces. Among the six sequences recognized, four were clearly delineated as representative of regression, subaerial exposure, and subsequent transgression. Two sequences were less clearly defined and probably represent transitional facies which had exposure surfaces developed. Comparison of the petrologically established sequence stratigraphy with published sea level curves resulted in a strong correlation between the number of sequences recognized and the number of coastal on-lap/off-lap cycles depicted for the early to middle Miocene. This correlation suggests that petrologic examination of core slabs, with supplemental thin section data, can provide useful information regarding the recognition of stratigraphic sequences and relative sea level fluctuations, particularly, in situations where seismic data may not be available.« less

Sequence stratigraphy of the Maastrichtian-Paleocene succession at the Dakhla Oasis, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Hewaidy, Abdel Galil A.; Farouk, Sherif; Bazeen, Youssef S.

2017-12-01

The Maastrichtian-Paleocene succession at the Dakhla Oasis is marked by the presence of a typical Nile Valley Facies represented by the Dakhla and Tarawan formations in Edmonstone and Qur El Malik sections in the central and western parts of the oasis, while a mixed Nile Valley and Garra Al-Arbain facies represented by Dakhla, Kurkur and Tarawan formations in Teneida section in the eastern part of the oasis adjacent to the Abu Tartur Plateau. These sections were examined for their foraminiferal contents, lithologic characters and stratigraphic boundaries. The distribution of foraminifera in the studied sections is variable and inconstant, as the planktonics are concentrated only at certain levels, which may be considered as a time intervals of transgression and maximum flooding surfaces. Eight planktonic biozones are distinguished in this work; of theses two are of Maastrichtain age and six are of Paleocene age. Eight 3rd order depositional sequences are recognized in the studied Maastrichtian-Paleocene succession based on the time stratigraphic boundaries released from the planktonic foraminifera and sea level changes which are released from the paleoecologic interpretations. The distinguished sequences are subdivided into their systems tracts based on the paleobathymetric interpretations of P/B% and benthic biofacies analysis. These sequences are bounded by eight sequence boundaries (SB A - SB H) represented by unconformity surfaces and depositional hiatuses. The correlation of the sequence boundaries of the established depositional sequences with the eustatic sea level curve, suggesting that these depositional sequences were resulted from the interplay of eustatic sea-level changes and local tectonic activities.

Palaeoredox conditions and sequence stratigraphy of the Cretaceous storm-dominated, mixed siliciclastic-carbonate ramp in the Eastern Cordillera Basin (Colombia): Evidence from sedimentary geochemical proxies and facies analysis

NASA Astrophysics Data System (ADS)

Rivera, Huber A.; Le Roux, Jacobus P.; Sánchez, L. Katherine; Mariño-Martínez, Jorge E.; Salazar, Christian; Barragán, J. Carolina

2018-10-01

The Cretaceous black shales of Colombia are among the most important successions in the north of South America and have attracted the attention of many geoscientists and exploration companies over the last few decades, because of their high hydrocarbon potential and the presence of emerald deposits. However, many uncertainties still remain with regard to their tectonic setting, sequence stratigraphy, depositional environments, palaeoxygenation conditions, and organic matter preservation. In order to develop a more integrated picture of these different processes and conditions, we conducted a detailed sedimentological, inorganic geochemical (U, V, Ni, Zn, Mn, Fe, Ti, Mo, Cu, Cr, Cd, Ba) and sequence stratigraphic analysis of the Cretaceous black shales in the Magdalena-Tablazo Sub-Basin (Eastern Cordillera Basin) of Colombia. Eleven lithofacies and five lithofacies associations of a storm-dominated, siliciclastic-carbonate ramp were identified, which range from basin to shallow inner ramp environments. These facies were grouped into six third-order stratigraphic sequences showing high-order cycles of marine transgression with constrained regressive pulses during the late Valanginian to early Coniacian. The black shales succession represents deposition under anoxic bottom water with some intervals representing dysoxic-suboxic conditions. The evolution of the sedimentary environments and their palaeoxygenation history reflect tectonic and eustatic sea-level controls that 1) produced a variable orientation and position of the coastline throughout the Cretaceous; 2) conditioned the low-gradient ramp geometry (<0.3°) and 3) modified the oxygenation conditions in the Magdalena-Tablazo Sub-Basin. An improved understanding of the sedimentary setting during deposition of the Cretaceous black shales in the Magdalena-Tablazo Sub-Basin assists in highlighting the interplay between the mechanism of sedimentation and continuum anoxic conditions prevailing in a basin, as well the important role of nutrient input from continental runoff as a trigger of high productivity and extended anoxia conditions.

Paleocene to Middle Miocene planktic foraminifera of the southwestern Salisbury Embayment, Virginia and Maryland: biostratigraphy, allostratigraphy, and sequence stratigraphy

USGS Publications Warehouse

Poag, C.W.; Commeau, J.A.

1995-01-01

The Paleocene to Middle Miocene sedimentary fill of the southwestern Salisbury Embayment contains a fragmental depositional record, interrupted by numerous local diastems and regional unconformities. Using planktic foraminiferal biostratigraphy, 15 unconformity-bounded depositional units have been identified, assigned to six formations and seven alloformations previously recognized in the embayment. The units correlate with second- and third-order sequences of the Exxon sequence stratigraphy model, and include transgressive and highstand systems tracts. Alloformation, formation, and sequence boundaries are marked by abrupt, scoured, burrowed, erosional surfaces, which display lag deposits, biostratigraphic gaps, and intense reworking of microfossils above and below the boundaries.Paleocene deposits represent the upper parts of upper Pleocene Biochronozones P4 and P5, and rest uncomformably  on Cretaceous sedimentary beds of various ages (Maastrichtian to Albian). Lower Eocene deposits represent parts of Biochronozones P6 and P9. Middle Eocene strata represent mainly parts of Biochronozones P11, P12, and P14. Upper Eocene sediments include parts of Biochronozones P15, P16, and P17. Oligocene deposits encompass parts of Biochronozones. N4b to N7 undifferentiated, P21a, and, perhaps, N4a. Lower Miocene deposits encompass parts of Biochronozones N4b to N7 undifferentiated. Middle Miocene strata represent mainly parts of Biochronorones N8, N9, and N10.Nine plates of scanning electron micrographs illustrate the principal planktic foraminifera used to establish the biostratigraphic framework. Two new informal formine of Praeterenuitella praegemma Li, 1987, are introduced.

Sequence stratigraphy and sedimentary study on Mishrif formation of Fauqi Oilfield of Missan in south east Iraq

NASA Astrophysics Data System (ADS)

Sang, Hua; Lin, Changsong; Jiang, Yiming

2017-05-01

The reservoir of Mishrif formation has a large scale distribution of marine facies carbonate sediments in great thickness in central and south east Iraq. Rudist reef and shoal facies limestones of the Mishrif Formation (Late Cenomanian - Middle Turonian) form a great potential reservoir rocks at oilfields and structures of Iraq. Facies modelling was applied to predict the relationship between facies distribution and reservoir characteristics to construct a predictive geologic model which will assist future exploration and development in south east Iraq. Microfacies analysis and electrofacies identification and correlations indicate that the limestone of the Mishrif Formation were mainly deposited in open platform setting. Sequence stratigraphic analyses of the Mishrif Formation indicate 3 third order depositional sequences.

Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, G.H.; Watkins, J.S.

1996-12-31

The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressivemore » interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.« less

Sequence stratigraphy and hydrocarbon potential of the Phu Khanh Basin offshore central Vietnam, South China Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, G.H.; Watkins, J.S.

1996-01-01

The Phu Khanh Basin offshore central Vietnam is one of the few untested basins on the Vietnam margin of the South China Sea. Analysis of over 1,600 km of multi-channel seismic reflection data indicates that the Phu Khanh Basin follows a typical rift-margin order: faulted basement, synrift sedimentation, a breakup unconformity, and postrift sedimentation. Postrift sedimentation consists of a transgressive phase characterized by ramp-like depositional geometries followed by a regressive phase characterized by prograding sequences. An early middle Miocene unconformity separates these two phases. During the transgressive phase rising sea level provided favorable conditions for carbonate buildup development. The regressivemore » interval contains a number of third-order depositional sequences composed of seismically resolvable lowstand, highstand, and rarely, transgressive systems tracts. Lacustrine sediments deposited in graben and half-graben lakes during the rifting stage are probably the principal source rocks. Fractured and/or weathered basement, carbonate complexes, basinfloor fans, and shallows water sands may have good reservoir quality. Potential traps include basement hills, carbonate complexes, fault taps, and stratigraphic traps within lowstand systems tracts. Hydrocarbon indicators such as flat spots, bright spots, gas chimneys with gas mounds on the seafloor occur at a number of locations.« less

Effects of Different Materials Used for Internal Floating Electrode on the Photovoltaic Properties of Tandem Type Organic Solar Cell

NASA Astrophysics Data System (ADS)

Triyana, Kuwat; Yasuda, Takeshi; Fujita, Katsuhiko; Tsutsui, Tetsuo

2004-04-01

Three thin heterojunctions sandwiched between indium tin oxide (ITO) and the top electrode as triple-heterojunction organic solar cells have been fabricated. Each heterojunction cell consists of CuPc as a donor layer and perilene tetracrboxylic-bis-benzimidazole (PTCBI) as an acceptor layer. Ultra thin (1 nm average thickness) layers of Ag or Au have been inserted between two heterojunctions as an internal electrode. Ag and Au were chosen as materials both for internal floating and top electrodes. Influences of different deposition sequences of the organic layer in each heterojunction cell and different electrode materials were also investigated. The optimum devices were obtained when the same material was used both as an internal electrode and a top electrode. When the deposition sequence of the heterojunction is PTCBI/CuPc, the most suitable electrode is Au and the ITO is negative relative to the top electrode. Meanwhile, Ag is suitable for an electrode when the deposition sequence is CuPc/PTCBI. In this second deposition sequence, the ITO is positive relative to the top electrode. The open circuit voltage (Voc) of both optimum devices is on the order of 1.35-1.5 V. These values are approximately three times higher than that in single-heterojunction organic solar cells.

Storm deposits as graves in Early Life: the Fezouata Lagerstätte case (Lower Ordovician, Morocco)

NASA Astrophysics Data System (ADS)

Vaucher, Romain; Pittet, Bernard; Hormière, Hélène; Martin, Emmanuel L. O.; Lefebvre, Bertrand

2016-04-01

The Fezouata Shale (Early Ordovician, Morocco) is renowned in the palaeontological community for its Konservat-Lagerstätte (Tremadocian in age) that yielded thousands of exceptionally well-preserved fossils (EPF) from the Great Ordovician Biodiversification Event. Lower Ordovician deposits in the central Anti-Atlas Mountain (Zagora area) are expressed by the Fezouata Shale and the Zini Formation. They consist in ca. 900m of siltstones and sandstones deposited in an epicontinental sea at the periphery of the Gondwanaland. Sedimentologic field analysis and sequence analysis were achieved on ten stratigraphic sections in order to constrain the palaeoenvironmental context of the Fezouata Biota and to predict the location (geographically and stratigraphically) of new Lagerstätten. Sedimentary structures (cm- to m-scale symmetrical ripples) and geometries (lobe, lobe-channel) point to storm dominance on the sedimentation but peculiar sedimentary features suggest a tide modulation. Thus, a wave-dominated tide-modulated model of deposition recording proximal offshore to shoreface environments for the Fezouata Shale and shoreface to foreshore environments for the overlying Zini Fm is proposed. Layers yielding EPF are argillaceous siltstones (with wave ripples of cm-scale wavelength) always overlain by fine-grained sandstones (distal storm deposits, few cm-thick, several m-long, with cm- to dm-scale hummocky cross-stratifications). Fast burying by storm deposits appear to be of prime importance to initiate the exceptional preservation of the soft tissues of animals in the fossil record. According to the model of deposition it correspond to environments close to the storm weather wave base. Lower Ordovician succession was deposited during a 2nd order cycle, although 3rd and 4th order cycles were also identified. Encoding these different orders of sea level fluctuations giving a value of "1" for the deepest part of sequences (for each order) and a value of "0" for the shallowest, a reconstruction of the sea level fluctuation is then proposed. This reconstruction clearly highlights the stratigraphic position of the today discovered Lagerstätte. It also suggests that a second, younger (Floian in age) stratigraphic interval has very comparable sedimentary conditions in terms of facies and sea level, and has the potential for being a new Lagerstätte in the Fezouata Shale.

Impact of beaver ponds on river discharge and sediment deposition along the Chevral River, Ardennes, Belgium

NASA Astrophysics Data System (ADS)

Nyssen, Jan; Frankl, Amaury; Pontzeele, Jolien; De Visscher, Maarten; Billi, Paolo

2013-04-01

With the recovery of the European beaver (Castor fiber) and their capacity to engineer fluvial landscapes, questions arise as to how they influence river discharge and sediment transport. The Chevral river (Ardennes, Belgium) contains two beaver dam sequences which appeared in 2004 and count now about 30 dams. Flow discharges and sediment fluxes were measured at the in- and outflow of each dam sequence. Volumes of sediment deposited behind the dams were measured. Between 2004 and 2011, peak flows were topped off, and the magnitude of extreme events decreased. 1710 m³ of sediment were deposited behind the beaver dams, with an average sediment thickness of 25 cm. The thickness of the sediment layer is related to the area of the beaver ponds. Along the stream, beaver pond sediment thickness displayed a sinusoidal deposition pattern, in which ponds with thick sediment layers were preceded by a series of ponds with thinner sediment layers. A downstream textural coarsening in the dam sequences was also observed, probably due to dam failures subsequent to surges. Differences in sediment flux between the in- and outflow at the beaver pond sequence were related to the river hydrograph, with deposition taking place during the rising limbs and slight erosion during the falling limbs. The seven-year-old sequences have filtered 190 tons of sediment out of the Chevral river, which is of the same order of magnitude as the 374 tons measured in pond deposits, with the difference between the values corresponding to beaver excavations (60 tons), inflow from small tributaries, and runoff from the valley flanks. Hydrogeomorphic effects of C. fiber and C. canadensis activity are similar in magnitude. The detailed analysis of changes to hydrology in beaver pond sequences confirms the potential of beavers to contribute to river and wetland restoration and catchment management.

The relationship between shellbed type and sequence architecture: examples from Japan and New Zealand

NASA Astrophysics Data System (ADS)

Kondo, Yasuo; Abbott, Stephen T.; Kitamura, Akihisa; Kamp, Peter J. J.; Naish, Tim R.; Kamataki, Takanobu; Saul, Gordon S.

1998-12-01

Examples of lithology, fossil content and taphonomic features of shellbeds and intervening less fossiliferous intervals are presented from four Plio-Pleistocene successions (Shimosa Group, Boso Peninsula, Omma Formation, Hokuriku area, Japan, and Okehu, Kai-iwi, and Shakespeare groups in Wanganui, and the Rangitikei Group along the Rangitikei River in New Zealand). As for pre-Pliocene 3rd- and 4th-order depositional sequences, Plio-Pleistocene 5th- to 7th-order depositional sequences contain a variety of shellbeds which are often associated with surfaces or intervals that are characterized by sedimentary condensation, omission or erosion (e.g. sequence boundaries, ravinement surfaces, downlap surfaces and condensed sections). Stratigraphic patterns of shellbed type tend to be similar and repetitive within a basin and a locality. This demonstrates that a specific palaeogeography played an important role in determining the nature of shellbeds. For example, shellbeds formed in the context of toplap are common only in the Shimosa Group, which was deposited in a moderately sheltered sea, the palaeo-Tokyo Bay. Toplap shellbeds are rare in other sequences formed in more open conditions. Despite the variability resulting from such basin characteristics, common styles of shellbeds can be recognized that formed under conditions of marine onlap, backlap, downlap and toplap. Each type of shellbed has a characteristic fossil composition and taphonomy. Onlap and toplap shellbeds contain low-diversity macrobenthic associations including Glycymeris, Mercenaria, Paphies or other bivalves having robust shells, which are often abraded or fragmented. Backlap shellbeds, which are equivalent to the condensed section formed at the maximum transgression, are characterized by dominance of epifaunal macrobenthos such as bryozoa, brachiopoda, pectinid and ostreid bivalves, preserved in a slightly cemented, glauconitic muddy matrix. In contrast to fossils in such condensed sections, the shell density and species diversity of downlap shellbed associations are rather low, and in a few examples the macrobenthic association was buried rapidly in a lower unit of the highstand systems tract (HST) stratigraphically located above the condensed sections. Variations in the stratigraphic distribution of shellbed types are reflected in symmetrical and asymmetrical sequence architectures. Symmetrical sequences have roughly the same thickness of transgressive systems tracts (TST) and highstand systems tracts (HST), and have well segregated shellbeds that were formed during marine onlap and backlap. Asymmetrical cycles have very thin TSTs and much thicker HSTs, and are characterized by the amalgamation of condensed onlap and backlap shellbeds. Such contrasting cycle architectures are interpreted to reflect inner (symmetrical) and outer (asymmetrical) shelf palaeodepositional settings. The amalgamated onlap/backlap shellbeds appear to be common in Plio-Pleistocene sequences. Owing to the short duration of glacio-eustatic sea-level changes with dominant frequencies of 20,000, 40,000 or 100,000 years, shellbeds in the Plio-Pleistocene are relatively simple and thin compared to those formed in ordinary third-order depositional sequences. Infauna-dominated benthic associations are generally more common than in third-order cycles, and epifaunal associations facilitated by taphonomic feedback on sediment-starved shell-gravel substrates occur only in the condensed section corresponding to maximum transgression in most Plio-Pleistocene sequences.

Transgressive systems tract development and incised-valley fills within a quaternary estuary-shelf system: Virginia inner shelf, USA

USGS Publications Warehouse

Foyle, A.M.; Oertel, G.F.

1997-01-01

High-frequency Quaternary glacioeustasy resulted in the incision of six moderate- to high-relief fluvial erosion surfaces beneath the Virginia inner shelf and coastal zone along the updip edges of the Atlantic continental margin. Fluvial valleys up to 5 km wide, with up to 37 m of relief and thalweg depths of up to 72 m below modern mean sea level, cut through underlying Pleistocene and Mio-Pliocene strata in response to drops in baselevel on the order of 100 m. Fluvially incised valleys were significantly modified during subsequent marine transgressions as fluvial drainage basins evolved into estuarine embayments (ancestral generations of the Chesapeake Bay). Complex incised-valley fill successions are bounded by, or contain, up to four stacked erosional surfaces (basal fluvial erosion surface, bay ravinement, tidal ravinement, and ebb-flood channel-base diastem) in vertical succession. These surfaces, combined with the transgressive oceanic ravinement that generally caps incised-valley fills, control the lateral and vertical development of intervening seismic facies (depositional systems). Transgressive stratigraphy characterizes the Quaternary section beneath the Virginia inner shelf where six depositional sequences (Sequences I-VI) are identified. Depositional sequences consist primarily of estuarine depositional systems (subjacent to the transgressive oceanic ravinement) and shoreface-shelf depositional systems; highstand systems tract coastal systems are thinly developed. The Quaternary section can be broadly subdivided into two parts. The upper part contains sequences consisting predominantly of inner shelf facies, whereas sequences in the lower part of the section consist predominantly of estuarine facies. Three styles of sequence preservation are identified. Style 1, represented by Sequences VI and V, is characterized by large estuarine systems (ancestral generations of the Chesapeake Bay) that are up to 40 m thick, have hemicylindrical wedge geometries, and occur within large, coast-oblique trending depressions (paleo-estuaries). Style 1 is dominated by fluvial through estuary-mouth depositional systems (Seismic Facies 1-4). Style 2 sequence preservation, represented by Sequences III and II, is dominantly an inner shelf and shoreface succession with a seaward-thickening tabular wedge geometry that does not exceed 15 m in thickness. These shoreface and inner shelf depositional systems of the upper transgressive systems tract (Seismic Facies 9) and highstand systems tract (Seismic Facies 7 and 11) are not associated with paleo-estuaries. Style 3 sequence preservation is represented by Sequence 1, the Holocene Sequence. It consists of lower transgressive systems tract fluvial-estuarine, lagoonal, and tidal-inlet fill deposits (Seismic Facies 1-6, and 8) overlain by upper transgressive systems tract shelf and shoreface sands (Seismic Facies 9). Style 3 has a crenulated wedge geometry, and is thickest beneath and seaward of the modern Chesapeake Bay mouth. It thins northward and landward onto Late Pleistocene interfluvial highs on the basinward side of the southern Delmarva Peninsula.

Stratigraphy, facies architecture, and palaeoenvironment of Neoproterozoic volcanics and volcaniclastic deposits in Fatira area, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Khalaf, Ezz El Din Abdel Hakim

Fatira area in the Central Eastern Desert, Egypt, is a composite terrane consisting of Neoproterozoic volcanics and sediments laid down in submarine to subaerial environment, intruded by voluminous old to young granitic rocks. The various lithofacies of the study area can be grouped in three distinct lithostratigraphic sequences, which are described here in stratigraphic order, from base to top as the Fatira El Beida, Fatira El Zarqa and Gabal Fatira sequences. Each depositional sequence, is intimately related to volcanic activity separated by time intervals of volcanic inactivity, such as marked hiatuses, reworked volcaniclasts, and or turbidite sedimentation. Four submarine facies groups have been recognized within the oldest, folded eruption sequence of Fatira El Beida. The southern part of the study area is occupied by sheet lava (SL), pillow lavas (PL), pillow breccias (PB), and overlying Bouma turbiditic volcaniclastites (VC). The four facies groups of Fatira El Beida sequence occur in a predictable upward-deepening succession, essentially from base to top, an SL-PL-PB-VC stacking pattern. The coeval tholeiitic mafic and felsic volcaniclastic rocks of this sequence indicate an extensional back-arc tectonic setting. The El Beida depositional sequence appears to fit a submarine-fan and slope-apron environment in an intra-arc site. The Fatira El Zarqa sequence involves a large volume of subaerial calc-alkaline intermediate to felsic volcanics and an unconformably overlying siliciclastic succession comprising clast-supported conglomerates (Gm), massive sandstone sheet floods (Sm) and mudstones (FI), together with a lateritic argillite paleosol (P) top formed in an alluvial-fan system. The youngest rock of Gabal Fatira sequence comprises anorogenic trachydacites and rhyolites with locally emergent domes associated with autobrecciation and sill-dyke rock swarms that could be interpreted as feeders and subvolcanic intrusions. Unconformity and lithofacies assemblages define seven events and three unconformity-bounded tectonic stages that record uplift-subsidence cycles in the study area. A proximal-distal relationship has been established within the depositional products, based on the relative dominance of erosional and depositional features.

Sequence stratigraphy of the Lower Triassic Sinbad Formation, San Rafael Swell, east-central, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodspeed, T.H.; Elrick, M.; Lucas, S.G.

1993-04-01

The Lower Triassic Sinbad Fm (20--30 m thick) in the San Rafael Swell of east-central Utah is high energy carbonate deposits that conformably overlie tidal flat/fluvial channel deposits of the Black Dragon Fm. The Torrey Fm conformably overlies the Sinbad Fm and consists primarily of siliciclastic tidal flat and fluvial deposits. Five facies (in ascending order) are characteristic of the Sinbad Fm: (1) bioturbated calcisiltite with calcite-replaced evaporite nodules and ripple laminations, (2) skeletal-oolitic-intraclastic packstone and grainstone, (3) slightly bioturbated, mechanically laminated, pelletal calcisiltite (5) trough cross-bedded, peloidal to oolitic grainstone, and (5) thin-bedded, skeletal-pelletal-oolitic grainstone with mud to wackestonemore » drapes. Regional facies relationships of the Sinbad Fm indicate initial deepening followed by shallowing. The skeletal-intraclastic packstone and grainstone facies represents maximum flooding. This facies thickens to the northwest and contains an open marine molluscan fauna of ammonites, bivalves, gastropods and scaphopods. The ammonites are indicative of the Tardus Zone of late Smithian age. Deposits above the maximum flooding zone (MFZ) are restricted foreshoal, pelletal calcisiltite, oolitic shoal, and backshoal skeletal-oolitic (with a restricted fauna of molluscs and ostracods) deposits. This shallowing-upward sequence represents the early HST. The Sinbad Fm represents the MFZ and early HST of a 150-m-thick depositional sequence of rocks with the Black Dragon FM representing the TST, and the Torrey Fm representing the late HST.« less

Fossils out of sequence: Computer simulations and strategies for dealing with stratigraphic disorder

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cutler, A.H.; Flessa, K.W.

Microstratigraphic resolution is limited by vertical mixing and reworking of fossils. Stratigraphic disorder is the degree to which fossils within a stratigraphic sequence are not in proper chronological order. Stratigraphic disorder arises through in situ vertical mixing of fossils and reworking of older fossils into younger deposits. The authors simulated the effects of mixing and reworking by simple computer models, and measured stratigraphic disorder using rank correlation between age and stratigraphic position (Spearman and Kendall coefficients). Mixing was simulated by randomly transposing pairs of adjacent fossils in a sequence. Reworking was simulated by randomly inserting older fossils into a youngermore » sequence. Mixing is an inefficient means of producing disorder; after 500 mixing steps stratigraphic order is still significant at the 99% to 95% level, depending on the coefficient used. Reworking disorders sequences very efficiently: significant order begins to be lost when reworked shells make up 35% of the sequence. Thus a sequence can be dominated by undisturbed, autochthonous shells and still be disordered. The effects of mixing-produced disorder can be minimized by increasing sample size at each horizon. Increased spacing between samples is of limited utility in dealing with disordered sequences: while widely separated samples are more likely to be stratigraphically ordered, the smaller number of samples makes the detection of trends problematic.« less

Metre-scale cyclicity in Middle Eocene platform carbonates in northern Egypt: Implications for facies development and sequence stratigraphy

NASA Astrophysics Data System (ADS)

Tawfik, Mohamed; El-Sorogy, Abdelbaset; Moussa, Mahmoud

2016-07-01

The shallow-water carbonates of the Middle Eocene in northern Egypt represent a Tethyan reef-rimmed carbonate platform with bedded inner-platform facies. Based on extensive micro- and biofacies documentation, five lithofacies associations were defined and their respective depositional environments were interpreted. Investigated sections were subdivided into three third-order sequences, named S1, S2 and S3. Sequence S1 is interpreted to correspond to the Lutetian, S2 corresponds to the Late Lutetian and Early Bartonian, and S3 represents the Late Bartonian. Each of the three sequences was further subdivided into fourth-order cycle sets and fifth-order cycles. The complete hierarchy of cycles can be correlated along 190 km across the study area, and highlighting a general "layer-cake" stratigraphic architecture. The documentation of the studied outcrops may contribute to the better regional understanding of the Middle Eocene formations in northern Egypt and to Tethyan pericratonic carbonate models in general.

Quantitative controls on location and architecture of carbonate depositional sequences: Upper miocene, cabo de gata region, SE Spain

USGS Publications Warehouse

Franseen, E.K.; Goldstein, R.H.; Farr, M.R.

1997-01-01

Sequence stratigraphy, pinning-point relative sea-level curves, and magnetostratigraphy provide the quantitative data necessary to understand how rates of sea-level change and different substrate paleoslopes are dominant controls on accumulation rate, carbonate depositional sequence location, and internal architecture. Five third-order (1-10 my) and fourth-order (0.1-1.0 my) upper Miocene carbonate depositional sequences (DS1A, DS1B, DS2, DS3, TCC) formed with superimposed higher-frequency sea-level cycles in an archipelago setting in SE Spain. Overall, our study indicates when areas of high substrate slope (> 15??) are in shallow water, independent of climate, the location and internal architecture of carbonate deposits are not directly linked to sea-level position but, instead, are controlled by location of gently sloping substrates and processes of bypass. In contrast, if carbonate sediments are generated where substrates of low slope ( 15.6 cm/ky to ??? 2 cm/ky and overall relative sea level rose at rates of 17-21.4 cm/ky. Higher frequency sea-level rates were about 111 to more than 260 cm/ky, producing onlapping, fining- (deepening-) upward cycles. Decreasing accumulation rates resulted from decreasing surface area for shallow-water sediment production, drowning of shallow-water substrates, and complex sediment dispersal related to the archipelago setting. Typical systems tract and parasequence development should not be expected in "bypass ramp" settings; facies of onlapping strata do not track base level and are likely to be significantly different compared to onlapping strata associated with coastal onlap. Basal and upper DS2 reef megabreccias (indicating the transition from cool to warmer climatic conditions) were eroded from steep upslope positions and redeposited downslope onto areas of gentle substrate during rapid sea-level falls (> 22.7 cm/ky) of short duration. Such rapid sea-level falls and presence of steep slopes are not conducive to formation of forced regressive systems tracts composed of down-stepping reef clinoforms. The DS3 reefal platform formed where shallow water coincided with gently sloping substrates created by earlier deposition. Slow progradation (0.39-1.45 km/my) is best explained by the lack of an extensive bank top, progressively falling sea level, and low productivity resulting from siliciclastic debris and excess nutrients shed from nearby volcanic islands. Although DS3 strata were deposited during a third-order relative sea-level cycle, a typical transgressive systems tract is not recognizable, indicating that the initial relative rise in sea level was too rapid (??? 19 cm/ky). Downstepping reefs, forming a forced regressive systems tract, were deposited during the relative sea-level fall at the end of DS3, indicating that relatively slow rates of fall (10 cm/ky or less) over favorable paleoslope conditions are conducive to generation of forced regressive systems tracts consisting of downstepping reef clinoforms. The TCC sequence consists of four shallow-water sedimentary cycles that were deposited during a 400 ky to 100 ky time span. Such shallow-water cycles, typical of many platforms, form only where shallow water intersects gently sloping substrates. The relative thicknesses of cycles (< 2 m to 15 m thick), magnitudes of relative sea-level fluctuations associated with each cycle (25-30 m), high rates of relative sea-level fluctuations (minimum of 25-120 cm/ky), and the widespread distribution of similar TCC cycles in the Mediterranean and elsewhere are supportive of a glacio-eustatic

Quantitative controls on location and architecture of carbonate depositional sequences: upper miocene, cabo de gata region, se Spain

USGS Publications Warehouse

Franseen, E.K.; Goldstein, R.H.; Farr, M.R.

1998-01-01

Sequence stratigraphy, pinning-point relative sea-level curves, and magnetostratigraphy provide the quantitative data necessary to understand how rates of sea-level change and different substrate paleoslopes are dominant controls on accumulation rate, carbonate depositional sequence location, and internal architecture. Five third-order (1-10 my) and fourth-order (0.1-1.0 my) upper Miocene carbonate depositional sequences (DS1A, DS1B, DS2, DS3, TCC) formed with superimposed higher-frequency sea-level cycles in an archipelago setting in SE Spain. Overall, our study indicates when areas of high substrate slope (> 15??) are in shallow water, independent of climate, the location and internal architecture of carbonate deposits are not directly linked to sea-level position but, instead, are controlled by location of gently sloping substrates and processes of bypass. In contrast, if carbonate sediments are generated where substrates of low slope ( 15.6 cm/ky to ??? 2 cm/ky and overall relative sea level rose at rates of 17-21.4 cm/ky. Higher frequency sea-level rates were about 111 to more than 260 cm/ky, producing onlapping, fining- (deepening-) upward cycles. Decreasing accumulation rates resulted from decreasing surface area for shallow-water sediment production, drowning of shallow-water substrates, and complex sediment dispersal related to the archipelago setting. Typical systems tract and parasequence development should not be expected in "bypass ramp" settings; facies of onlapping strata do not track base level and are likely to be significantly different compared to onlapping strata associated with coastal onlap. Basal and upper DS2 reef megabreccias (indicating the transition from cool to warmer climatic conditions) were eroded from steep upslope positions and redeposited downslope onto areas of gentle substrate during rapid sea-level falls (> 22.7 cm/ky) of short duration. Such rapid sea-level falls and presence of steep slopes are not conducive to formation of forced regressive systems tracts composed of downstepping reef clinoforms. The DS3 reefal platform formed where shallow water coincided with gently sloping substrates created by earlier deposition. Slow progradation (0.39-1.45 km/my) is best explained by the lack of an extensive bank top, progressively falling sea level, and low productivity resulting from siliciclastic debris and excess nutrients shed from nearby volcanic islands. Although DS3 strata were deposited during a third-order relative sea-level cycle, a typical transgresse??e systems tract is not recognizable, indicating that the initial relative rise in sea level was too rapid (??? 19 cm/ky). Downstepping reefs, forming a forced regressive systems tract, were deposited during the relative sea-level fall at the end of DS3, indicating that relatively slow rates of fall (10 cm/ky or less) over favorable paleoslope conditions are conducive to generation of forced regressive systems tracts consisting of downstepping reef clinoforms. The TCC sequence consists of four shallow -water sedimentary cycles that were deposited during a 400 ky to 100 ky time span. Such shallow-water cycles, typical of many platforms, form only where shallow water intersects gently sloping substrates. The relative thicknesses of cycles (< 2 m to 15 m thick), magnitudes of relative sea-level fluctuations associated with each cycle (25-30 m), high rates of relative sea-level fluctuations (minimum of 25-120 cm/ky), and the widespread distribution of similar TCC cycles in the Mediterranean and elsewhere are supportive of a glacio-eustati

Effects of the Laramide Structures on the Regional Distribution of Tight-Gas Sandstone in the Upper Mesaverde Group, Uinta Basin, Utah

NASA Astrophysics Data System (ADS)

Sitaula, R. P.; Aschoff, J.

2013-12-01

Regional-scale sequence stratigraphic correlation, well log analysis, syntectonic unconformity mapping, isopach maps, and depositional environment maps of the upper Mesaverde Group (UMG) in Uinta basin, Utah suggest higher accommodation in northeastern part (Natural Buttes area) and local development of lacustrine facies due to increased subsidence caused by uplift of San Rafael Swell (SRS) in southern and Uinta Uplift in northern parts. Recently discovered lacustrine facies in Natural Buttes area are completely different than the dominant fluvial facies in outcrops along Book Cliffs and could have implications for significant amount of tight-gas sand production from this area. Data used for sequence stratigraphic correlation, isopach maps and depositional environmental maps include > 100 well logs, 20 stratigraphic profiles, 35 sandstone thin sections and 10 outcrop-based gamma ray profiles. Seven 4th order depositional sequences (~0.5 my duration) are identified and correlated within UMG. Correlation was constructed using a combination of fluvial facies and stacking patterns in outcrops, chert-pebble conglomerates and tidally influenced strata. These surfaces were extrapolated into subsurface by matching GR profiles. GR well logs and core log of Natural Buttes area show intervals of coarsening upward patterns suggesting possible lacustrine intervals that might contain high TOC. Locally, younger sequences are completely truncated across SRS whereas older sequences are truncated and thinned toward SRS. The cycles of truncation and thinning represent phases of SRS uplift. Thinning possibly related with the Uinta Uplift is also observed in northwestern part. Paleocurrents are consistent with interpretation of periodic segmentation and deflection of sedimentation. Regional paleocurrents are generally E-NE-directed in Sequences 1-4, and N-directed in Sequences 5-7. From isopach maps and paleocurrent direction it can be interpreted that uplift of SRS changed route of sediment supply from west to southwest. Locally, paleocurrents are highly variable near SRS further suggesting UMG basin-fill was partitioned by uplift of SRS. Sandstone composition analysis also suggests the uplift of SRS causing the variation of source rocks in upper sequences than the lower sequences. In conclusion, we suggest that Uinta basin was episodically partitioned during the deposition of UMG due to uplift of Laramide structures in the basin and accommodation was localized in northeastern part. Understanding of structural controls on accommodation, sedimentation patterns and depositional environments will aid prediction of the best-producing gas reservoirs.

Sediment budget as affected by construction of a sequence of dams in the lower Red River, Viet Nam

NASA Astrophysics Data System (ADS)

Lu, Xi Xi; Oeurng, Chantha; Le, Thi Phuong Quynh; Thuy, Duong Thi

2015-11-01

Dam construction is one of the main factors resulting in riverine sediment changes, which in turn cause river degradation or aggradation downstream. The main objective of this work is to examine the sediment budget affected by a sequence of dams constructed upstream in the lower reach of the Red River. The study is based on the longer-term annual data (1960-2010) with a complementary daily water and sediment data set (2008-2010). The results showed that the stretch of the river changed from sediment surplus (suggesting possible deposition processes) into sediment deficit (possible erosion processes) after the first dam (Thac Ba Dam) was constructed in 1972 and changed back to deposition after the second dam (Hoa Binh Dam) was constructed in 1985. The annual sediment deposition varied between 1.9 Mt/y and 46.7 Mt/y with an annual mean value of 22.9 Mt/y (1985-2010). The sediment deposition at the lower reach of the Red River would accelerate river aggradation which would change river channel capacity in the downstream of the Red River. The depositional processes could be sustained or changed back to erosional processes after more dams (the amount of sediment deposit was much less after the latest two dams Tuyen Quang Dam in 2009 and Sonla Dam in 2010) are constructed, depending on the water and sediment dynamics. This study revealed that the erosional and depositional processes could be shifted for the same stretch of river as affected by a sequence of dams and provides useful insights in river management in order to reduce flood frequency along the lower reach of the Red River.

Stratigraphic evolution of the Late Jurassic Hanifa Formation along the Tuwaiq Escarpment, Saudi Arabia: Evidence for a carbonate ramp system

NASA Astrophysics Data System (ADS)

Fallatah, Mohammed I.; Kerans, Charles

2018-01-01

A sequence stratigraphic framework of the Late Jurassic (Oxfordian) Hanifa Formation at its exposure in Central Arabia is presented for the first time. This study offers the first high-resolution stratigraphic framework of the Hanifa along the Tuwaiq Escarpment by measuring 15 sections ( 770 m total thickness) over an oblique-to-dip distance of 260 km and collecting 295 samples for petrographic analysis. On the basis of these data, the Hanifa Formation can be subdivided into eight facies; 1) tabular cross-bedded quartz-peloidal-skeletal grainstone, 2) cross-bedded skeletal-peloidal grainstone, 3) bioturbated foraminiferal wackestone/mud-dominated packstone, 4) oncolitic rudstone, 5) stromatoporoid-coral biostrome/bioherm, 6) peloidal/composite-grain grain-dominated packstone/grainstone, 7) bioturbated spiculitic wackestone/mud-dominated packstone, and 8) thinly-bedded argillaceous mudstone/wackestone. The vertical and lateral distributions of these facies along the exposure define their sequence setting using the principals of sequence stratigraphy. By recognizing erosional surfaces, facies offset, and changes in facies proportions, five third-order sequences, with an average duration of 1.1 Myr, are interpreted for the Hanifa Formation. The correlation of the sequences across the study area shows that only four sequences are preserved in the north where shallow-water deposits are well-developed. Facies trends within these sequences are further illustrated in depositional models representing the highstand systems tracts (HST) and the transgressive systems tracts (TST) of the Hanifa Formation. These proposed models represent depositional settings of a carbonate ramp with normal open-marine conditions. The HST depositional model is characterized by a high-energy shoreline and depicts the presence of an offshore, structurally controlled skeletal-peloidal shoal body described here for the first time at the Hanifa exposure in the Hozwa area. This work provides a predictive framework and outcrop analog for applications in hydrocarbon exploration and development. Furthermore, a basinal setting predicted to the south of the study area is a potential site for unconventional plays.

Deposition of a saline giant in the Mississippian Windsor Group, Nova Scotia, and the nascent Late Paleozoic Ice Age

NASA Astrophysics Data System (ADS)

MacNeil, Laura A.; Pufahl, Peir K.; James, Noel P.

2018-01-01

Saline giants are vast marine evaporite deposits that currently have no modern analogues and remain one of the most enigmatic of chemical sedimentary rocks. The Mississippian Windsor Group (ca. 345 Ma), Maritimes Basin, Atlantic Canada is a saline giant that consists of two evaporite-rich sedimentary sequences that are subdivided into five subzones. Sequence 1 is composed almost entirely of thick halite belonging to Subzone A (Osagean). Sequence 2 is in unconformable contact and comprised of stacked carbonate-evaporite peritidal cycles of Subzones B through E (Meramecian). Subzone B, the focus of research herein, documents the transition from wholly evaporitic to open marine conditions and thus, preserves an exceptional window into the processes forming saline giants. Lithofacies stacking patterns in Subzone B reveal that higher-order fluctuations in relative sea level produced nine stacked parasequences interpreted to reflect high frequency glacioeustatic oscillations during the onset of the Late Paleozoic Ice Age. Each parasequence reflects progradation of intertidal and sabkha sediments over subtidal carbonate and evaporite deposits. Dissimilarities in cycle composition between sub-basins imply the development of contrasting brine chemistries from differing recharge rates with the open ocean. What the Windsor Group shows is that evaporite type is ostensibly linked to the amplitude and frequency of sea level rise and fall during deposition. True saline giants, like the basinwide evaporites of Sequence 1, apparently require low amplitude, long frequency changes in sea level to promote the development of stable brine pools that are only periodically recharged with seawater. By contrast, the high amplitude, short frequency glacioeustatic variability in sea level that controlled the accumulation of peritidal evaporites in Subzone B produce smaller, subeconomic deposits with more complex facies relationships.

Complete Genome Sequence of Methanohalophilus halophilus DSM 3094T, Isolated from a Cyanobacterial Mat and Bottom Deposits at Hamelin Pool, Shark Bay, Northwestern Australia.

PubMed

L'Haridon, Stéphane; Corre, Erwan; Guan, Yue; Vinu, Manikandan; La Cono, Violetta; Yakimov, Mickail; Stingl, Ulrich; Toffin, Laurent; Jebbar, Mohamed

2017-02-16

The complete genome sequence of Methanohalophilus halophilus DSM 3094 T , a member of the Methanosarcinaceae family and the Methanosarcianales order, consists of 2,022,959 bp in one contig and contains 2,137 predicted genes. The genome is consistent with a halophilic methylotrophic anaerobic lifestyle, including the methylotrophic and CO 2 -H 2 methanogensis pathways. Copyright © 2017 L’Haridon et al.

Oligo-Miocene reservoir sequence characterization and structuring in the Sisseb El Alem-Kalaa Kebira regions (Northeastern Tunisia)

NASA Astrophysics Data System (ADS)

Houatmia, Faten; Khomsi, Sami; Bédir, Mourad

2015-11-01

The Sisseb El Alem-Enfidha basin is located in the northeastern Tunisia, It is borded by Nadhour - Saouaf syncline to the north, Kairouan plain to the south, the Mediterranean Sea to the east and Tunisian Atlassic "dorsale" to the west. Oligocene and Miocene deltaic deposits present the main potential deep aquifers in this basin with high porosity (25%-30%). The interpretation of twenty seismic reflection profiles, calibrated by wire line logging data of twelve oil wells, hydraulic wells and geologic field sections highlighted the impact of tectonics on the structuring geometry of Oligo-Miocene sandstones reservoirs and their distribution in raised structures and subsurface depressions. Miocene seismostratigraphy analysis from Ain Ghrab Formation (Langhian) to the Segui Formation (Quaternary) showed five third-order seismic sequence deposits and nine extended lenticular sandy bodies reservoirs limited by toplap and downlap surfaces unconformities, Oligocene deposits presented also five third- order seismic sequences with five extended lenticular sandy bodies reservoirs. The Depth and the thickness maps of these sequence reservoir packages exhibited the structuring of this basin in sub-basins characterized by important lateral and vertical geometric and thichness variations. Petroleum wells wire line logging correlation with clay volume calculation showed an heterogeneous multilayer reservoirs of Oligocene and Miocene formed by the arrangement of fourteen sandstone bodies being able to be good reservoirs, separated by impermeable clay packages and affected by faults. Reservoirs levels correspond mainly to the lower system tract (LST) of sequences. Intensive fracturing by deep seated faults bounding the different sub-basins play a great role for water surface recharge and inter-layer circulations between affected reservoirs. The total pore volume of the Oligo-Miocene reservoir sandy bodies in the study area, is estimated to about 4 × 1012 m3 and equivalent to 4 × 109 m3 of deep water reserves.

Tectonic controls on deposition of Middle Jurassic strata in a retroarc foreland basin, Utah-Idaho trough, western interior, United States

NASA Astrophysics Data System (ADS)

Bjerrum, Christian J.; Dorsey, Rebecca J.

1995-08-01

An electronic supplement of this material may be obtained on a diskette or Anonymous FTP from KOSMOS.AGU.ORG. (LOGIN to AGU's FTP account using ANONYMOUS as the username and GUEST as the password. Go to the right directory by typing CD APEND. Type LS to see what files are available. Type GET and the name of the file to get it. Finally, type EXIT to leave the system.) (Paper 95TC01448, Tectonic controls on deposition of Middle Jurassic strata in a retroarc foreland basin, Utah-Idaho trough, western interior, United States, Christian J. Bjerrum and Rebecca J. Dorsey). Diskette may be ordered from American Geophysical Union, 2000 Florida Avenue, N. W., Washington, DC 20009; $15.00. Payment must accompany order. A thick succession of Jurassic nonmarine and marine sedimentary rocks is exposed in a large area from northern Arizona to eastern Idaho and western Wyoming. These sediments accumulated in the Utah-Idaho trough, a deep elongate cratonal basin whose origin has recently been debated. Detailed stratigraphic analysis, subsidence analysis, and first-order flexural modeling of these deposits (this study) provide new insights into the timing and mechanisms of subsidence in the Utah-Idaho trough. Lower and Middle Jurassic strata are divided into six unconformity-bounded sequences. In contrast to the overall uniform thickness of Lower Jurassic sequences (1 and 2), Middle Jurassic strata (sequences 3 through 6) consist of distinctly westward thickening sedimentary packages in which basal shallow marine deposits onlap eastward onto bounding unconformities. Basal strata of sequences 3 through 6 pass upward into widespread progradational continental deposits that are truncated progressively toward the east (cratonward) by the next unconformity. Decompacted total subsidence curves show that the rate of subsidence in most sections increased sharply at the end of sequence 2 time (J-2 unconformity; ˜170 Ma). This is interpreted to record the onset of Middle Jurassic deposition in the distal part of a retroarc foreland basin. The unconformities and distinctive stratal geometries may have formed in response to forebulge migration caused by episodic thrusting in the Cordilleran orogen to the west. First-order flexural modeling was carried out to test the hypothesis of flexural subsidence in the Utah-Idaho trough. Trial-and-error comparisons produce a close match between decompacted stratigraphic profiles and model deflection profiles. The best fit is obtained using an infinite elastic plate (D = 1 × 1024 Nm), a moderate load topography, elevated base level, and an overfilled basin. Using recently published tectonic reconstructions for Nevada and Utah, we find close spatial agreement between a large Middle Jurassic fold-thrust belt and the supracrustal load inferred from model simulations. Our integrated basin analysis thus supports the interpretation of some previous studies that the Middle Jurassic Utah-Idaho trough was a retroarc foreland basin that formed east of a belt of regional contractile deformation and crustal thickening in western and central Nevada and southeastern California. Late Jurassic extension and normal faulting in northeastern Nevada may have been related to gravitational collapse of overthickened crust in the Cordilleran orogen. This coincides with a period of slowed subsidence in the Utah-Idaho trough that began at about 157 Ma.

Uplift sequence of the Andes at 30°S: Insights from sedimentology and U/Pb dating of synorogenic deposits

NASA Astrophysics Data System (ADS)

Suriano, J.; Mardonez, D.; Mahoney, J. B.; Mescua, J. F.; Giambiagi, L. B.; Kimbrough, D.; Lossada, A.

2017-04-01

The South Central Andes at 30°S represent a key area to understand the Andes geodynamics as it is in the middle of the flat slab segment and all the morphotectonic units of the Central Andes are well developed. This work is focused in the proximal synorogenic deposits of the Western Precordillera, in the La Tranca valley, in order to unravel the uplift sequence of this belt. Nine facies associations were recognized; most of them represent piedmont facies with local provenance from Precordillera and were deposited in the wedge-top depozone, as is expected for proximal sinorogenic deposits. However there are intercalations of transference fluvial systems, which show mixed provenance indicating that Permo-Triassic igneous rocks were already exposed to the west (Frontal Cordillera). There are also lacustrine deposits which are interpreted as the result of damming by fault activity at east of the studied basin. Finally, two maximum depositional ages at ca. 11 Ma and 8 Ma of these deposits indicate that the onset of uplift of the Precordillera at 30°S is little older than 11 Ma. These data change two previous ideas about the evolution of the Precordillera: its uplift at 30° S is younger than proposed by previous works and it is nearly synchronous along strike.

Earliest accumulation history of the north polar layered deposits, Mars from SHARAD

NASA Astrophysics Data System (ADS)

Nerozzi, Stefano; Holt, John W.

2018-07-01

The approximately 2 km thick north polar layered deposits (NPLD) are often considered to contain the most complete and detailed stratigraphic records of recent climate of Mars. Exposures of the dense layering within troughs and scarps allowed detailed reconstructions of the latest accumulation history of these water ice deposits, but we lack knowledge of their initial emplacement. The Shallow Radar (SHARAD) onboard Mars Reconnaissance Orbiter (MRO) penetrates the NPLD to their base and detects their internal layering, overcoming the limitation of scarce and scattered visible outcrops of the lowermost sequences. In this study, we map reflectors in SHARAD data that result from discrete stratigraphic horizons in order to delineate the three-dimensional stratigraphy of the lowermost ∼500 m NPLD sequence and reconstruct their accumulation history. We confirm the large-scale lateral continuity and thickness uniformity of the deposits previously detected within the lowermost NPLD. However, stratigraphic complexity-in the form of pinch-outs and significant thickness variations-arises when we examine single radar units. We find evidence of an initially limited geographic stability of water ice within two deposits that are centered at the North Pole and present-day Gemina Lingula. A period of lateral ice sheet growth followed, interrupted only once by a retreat episode. Lower net accumulation is observed on pre-existing slopes, suggesting a reduction of water ice stability due to increased solar radiation incidence and/or transport by katabatic winds. Lateral transport of water ice by wind is also suggested by thickness undulations toward the top of the sequence, resembling cyclic steps. Water ice accumulation models based on orbital forcing predict a sequence of deposition and retreat events that is generally compatible with our reconstructed accumulation history. Therefore, we interpret the stratigraphic complexity that we observe as regional and, possibly global, climate change induced by orbital forcing. We also find that at least two units are completely buried within the NPLD and do not outcrop, and that NPLD deposition in some places was contemporaneous with deposition of the stratigraphically underlying cavi unit in other places. Both of these findings show that radar reflector mapping is a necessary complement to any stratigraphic reconstruction based on visible exposures.

Glutenite bodies sequence division of the upper Es4 in northern Minfeng zone of Dongying Sag, Bohai Bay Basin, China

NASA Astrophysics Data System (ADS)

Shao, Xupeng

2017-04-01

Glutenite bodies are widely developed in northern Minfeng zone of Dongying Sag. Their litho-electric relationship is not clear. In addition, as the conventional sequence stratigraphic research method drawbacks of involving too many subjective human factors, it has limited deepening of the regional sequence stratigraphic research. The wavelet transform technique based on logging data and the time-frequency analysis technique based on seismic data have advantages of dividing sequence stratigraphy quantitatively comparing with the conventional methods. Under the basis of the conventional sequence research method, this paper used the above techniques to divide the fourth-order sequence of the upper Es4 in northern Minfeng zone of Dongying Sag. The research shows that the wavelet transform technique based on logging data and the time-frequency analysis technique based on seismic data are essentially consistent, both of which divide sequence stratigraphy quantitatively in the frequency domain; wavelet transform technique has high resolutions. It is suitable for areas with wells. The seismic time-frequency analysis technique has wide applicability, but a low resolution. Both of the techniques should be combined; the upper Es4 in northern Minfeng zone of Dongying Sag is a complete set of third-order sequence, which can be further subdivided into 5 fourth-order sequences that has the depositional characteristics of fine-upward sequence in granularity. Key words: Dongying sag, northern Minfeng zone, wavelet transform technique, time-frequency analysis technique ,the upper Es4, sequence stratigraphy

Sequence stratigraphy of the siliciclastic East Puolanka Group, the Palaeoproterozoic Kainuu Belt, Finland

NASA Astrophysics Data System (ADS)

Strand, Kari

2005-04-01

The 2300-2600 m thick Palaeoproterozoic East Puolanka Group within the central Fennoscandian Shield records four major transgressions on the cratonic margin within the approximate time period 2.25-2.10 Ga. Stacking of siliciclastic facies in parasequences and parasequence sets provides data to evaluate oscillation of relative sea-level and subsidence on different temporal scales. The lowermost part of the passive margin prism is characterized by alluvial plain to shallow marine sediments deposited in incised valleys. The succeeding highstand period is recorded by ca. 250 m of progradational parasequence sets of predominantly rippled and horizontally laminated sandstones, representing stacked wave-dominated shoreline units in sequence 1, capped by a hiatus or, in some places, by a subaerial lava. As relative sea-level rose again, sand-rich barrier-beach complexes developed with microtidal lagoons and inlets, corresponding to a retrogradational parasequence set. This was followed by a highstand period, with aggradation and progradation of alluvial plain and coastal sediments grading up into wave-tide influenced shoreline deposits in sequence 2. In sequence 3, the succeeding mudstones represent tidal flat deposits in a back-barrier region. With continued transgression, the parasequences stacked retrogradationally, each flooding episode being recorded by increasingly deeper water deposits above low-angle cross-bedded sandstones of the swash zones. The succeeding highstand progradation is represented by alluvial plain deposits. The next transgressive systems tract, overlying an inferred erosional ravinement surface, is recorded by a retrogradational parasequence set dominated by low-angle cross-stratified swash zone deposits in sequence 4. The large-scale trough cross-bed sets in these parasequences represent sand shoals and sheets of the inner shelf system. The overall major transgression recorded in the lowermost part of the Palaeoproterozoic cratonic margin succession was related to first- to second-order sea-level changes, probably due to increasing regional thermal subsidence of the lithosphere following partial continental breakup. The stratigraphic evolution can be related to changes of relative sea-level with a frequency of ca. 25 million years, probably propagated by episodic thermal subsidence. The parasequences identified here are related to high-frequency cycles of relative sea-level change due to low-magnitude eustatic oscillations.

Permian depositional history, Leach Mountains, northeastern Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martindale, S.G.

1993-04-01

The 4,000 m thick Permian sequence in the Leach Mountains consists of carbonate rock, chert, terrigenous clastic rock and phosphatic rock. These rocks, in ascending order, comprise the Third Fork Fm., Badger Gulch Fm., Trapper Creek Fm., Grandeur Fm., Meade Peak Phosphatic Shale Tongue of the Phosphoria Fm., Murdock Mountain Fm. and Gerster Limestone. This sequence disconformably overlain by Triassic strata. Initial Permian deposition, represented by the late Wolfcampian to early Leonardian Third Fork Fm., was on a slope, at a water depth of about 50 m. Subsequently, a shallowing trend occurred during the early Leonardian to late Leonardian withmore » deposition of the Badger Gulch, Trapper Creek and Grandeur Fms. The Trapper Creek and Grandeur Fms. were deposited on the shelf, in very shallow subtidal to supratidal environments. The shelf persisted through the remainder of the Permian. In the late leonardian, the Meade Peak Tongue was deposited in very shallow subtidal and intertidal environments. A supratidal environment was re-established in latest Leonardian( ) to early Guadalupian with deposition of the lower Murdock Mountain Fm. The upper Murdock Mountain Fm. was deposited in very shallow subtidal to supratidal environments. Later during the early Guadalupian, intertidal to shallow subtidal deposition of the Gerster Limestone occurred. Angular phosphatic pebbles that were derived from phosphatic strata at the top of the Gerster Limestone are contained in the Triassic basal conglomerate. These pebbles indicate that the last Permian event was probably emergence and erosion of the top of the Gerster Limestone.« less

Clinoforms in Melas Chasma

NASA Image and Video Library

2017-04-10

In this image from NASA's Mars Reconnaissance Orbiter, a group of steeply inclined light-toned layers is bounded above and below by unconformities (sudden or irregular changes from one deposit to another) that indicate a "break" where erosion of pre-existing layers was taking place at a higher rate than deposition of new materials. The layered deposits in Melas Basin may have been deposited during the growth of a delta complex. This depositional sequence likely represents a period where materials were being deposited on the floor of a lake or running river. The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 28.9 centimeters (11.4 inches) per pixel (with 1 x 1 binning); objects on the order of 87 centimeters (34.2 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA21580

Origin of phosphatic stromatolites in the Upper Cretaceous condensed sequence of the Polish Jura Chain

NASA Astrophysics Data System (ADS)

Krajewski, K. P.; Leśniak, P. M.; Łącka, B.; Zawidzki, P.

2000-10-01

The Turonian stromatolite-bearing condensed sequence in the Polish Jura Chain (the European epicontinental basin) provides good insight into the environment of formation of Cretaceous phosphatic stromatolites, owing to their purely phosphatic development and negligible post-depositional alteration. The sequence developed as a result of slow pelagic sedimentation and microbial mat phosphatization on a submarine swell surrounded by local basins with non-condensed carbonate deposition. Diagenesis of organic matter and dissolution of biogenic apatite were the major sources of reactive phosphorus for the microbial mat phosphatization. Stromatolite growth occurred due to pulses of amorphous or poorly ordered calcium phosphate precipitation followed by crystallization of carbonate fluorapatite (CFA). The phosphogenic environment left an imprint on the isotopic composition of limestone carbon and lattice-bound carbon and sulphur in CFA, and on the light rare-earth element (LREE) distribution in CFA. The δ13C of the stromatolite-bearing sequence shows a negative excursion (-1 to -3‰), standing in marked contrast to positive carbon values of the surrounding basinal carbonate. Most of the δ34S values of CFA (+20 to +21‰) fit the value range of the coeval seawater sulphate, and the LREE distribution shows a well-defined seawater pattern. This geochemical signature is indicative of intense diagenesis of organic matter at the seafloor, pelagic carbonate dissolution, and prolonged exposure of the deposited phosphate towards the water column. The enhanced deposition and diagenesis of organic phosphorus in the stromatolitic environment reflects elevated levels of the epicontinental basin nutrification related to sea-level rises and the associated oceanographic and geochemical changes.

In vivo Proton Electron Double Resonance Imaging of Mice with Fast Spin Echo Pulse Sequence

PubMed Central

Sun, Ziqi; Li, Haihong; Petryakov, Sergey; Samouilov, Alex; Zweier, Jay L.

2011-01-01

Purpose To develop and evaluate a 2D fast spin echo (FSE) pulse sequence for enhancing temporal resolution and reducing tissue heating for in vivo proton electron double resonance imaging (PEDRI) of mice. Materials and Methods A four-compartment phantom containing 2 mM TEMPONE was imaged at 20.1 mT using 2D FSE-PEDRI and regular gradient echo (GRE)-PEDRI pulse sequences. Control mice were infused with TEMPONE over ∼1 min followed by time-course imaging using the 2D FSE-PEDRI sequence at intervals of 10 – 30 s between image acquisitions. The average signal intensity from the time-course images was analyzed using a first-order kinetics model. Results Phantom experiments demonstrated that EPR power deposition can be greatly reduced using the FSE-PEDRI pulse sequence compared to the conventional gradient echo pulse sequence. High temporal resolution was achieved at ∼4 s per image acquisition using the FSE-PEDRI sequence with a good image SNR in the range of 233-266 in the phantom study. The TEMPONE half-life measured in vivo was ∼72 s. Conclusion Thus, the FSE-PEDRI pulse sequence enables fast in vivo functional imaging of free radical probes in small animals greatly reducing EPR irradiation time with decreased power deposition and provides increased temporal resolution. PMID:22147559

Identification of Genes and Pathways Related to Phenol Degradation in Metagenomic Libraries from Petroleum Refinery Wastewater

PubMed Central

Silva, Cynthia C.; Hayden, Helen; Sawbridge, Tim; Mele, Pauline; De Paula, Sérgio O.; Silva, Lívia C. F.; Vidigal, Pedro M. P.; Vicentini, Renato; Sousa, Maíra P.; Torres, Ana Paula R.; Santiago, Vânia M. J.; Oliveira, Valéria M.

2013-01-01

Two fosmid libraries, totaling 13,200 clones, were obtained from bioreactor sludge of petroleum refinery wastewater treatment system. The library screening based on PCR and biological activity assays revealed more than 400 positive clones for phenol degradation. From these, 100 clones were randomly selected for pyrosequencing in order to evaluate the genetic potential of the microorganisms present in wastewater treatment plant for biodegradation, focusing mainly on novel genes and pathways of phenol and aromatic compound degradation. The sequence analysis of selected clones yielded 129,635 reads at an estimated 17-fold coverage. The phylogenetic analysis showed Burkholderiales and Rhodocyclales as the most abundant orders among the selected fosmid clones. The MG-RAST analysis revealed a broad metabolic profile with important functions for wastewater treatment, including metabolism of aromatic compounds, nitrogen, sulphur and phosphorus. The predicted 2,276 proteins included phenol hydroxylases and cathecol 2,3- dioxygenases, involved in the catabolism of aromatic compounds, such as phenol, byphenol, benzoate and phenylpropanoid. The sequencing of one fosmid insert of 33 kb unraveled the gene that permitted the host, Escherichia coli EPI300, to grow in the presence of aromatic compounds. Additionally, the comparison of the whole fosmid sequence against bacterial genomes deposited in GenBank showed that about 90% of sequence showed no identity to known sequences of Proteobacteria deposited in the NCBI database. This study surveyed the functional potential of fosmid clones for aromatic compound degradation and contributed to our knowledge of the biodegradative capacity and pathways of microbial assemblages present in refinery wastewater treatment system. PMID:23637911

Facies analysis and depositional environments of upper part of Richmond group (upper Ordovician), Richmond, Indiana, to Xenia, Ohio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betz, C.E.; Martin, W.D.

Rock sections of the Drakes, Elkhorn, and Whitewater Formations were studied along an east-west-trending line in order to distinguish facies changes in a slope direction across the paleodepositional basin. The Richmond limestones, shales, and dolostones formed from fine-grained, terrigenous and carbonate sediments deposited on a shallow marine ramp within the humid, tropical, low latitudes of the Southern Hemisphere. Depositional environments on the ramp are represented by five main facies type. The five Richmond facies form a subtidal to supratidal shallowing-upward sequence. This progressive shallowing during the Late Ordovician resulted from the westward regional progradation of Queenston deltaic facies.

Tephrostratigraphy of the A.D. 79 pyroclastic deposits in perivolcanic areas of Mt. Vesuvio (Italy)

NASA Astrophysics Data System (ADS)

Lirer, Lucio; Munno, Rosalba; Petrosino, Paola; Vinci, Anna

1993-11-01

Correlations between pyroclastic deposits in perivolcanic areas are often complicated by lateral and vertical textural variations linked to very localized depositional effects. In this regard, a detailed sampling of A.D. 79 eruption products has been performed in the main archaeological sites of the perivolcanic area, with the aim of carrying out a grain-size, compositional and geochemical investigation so as to identify the marker layers from different stratigraphic successions and thus reconstruct the eruptive sequence. In order to process the large number of data available, a statistical approach was considered the most suitable. Statistical processing highlighted 14 marker layers among the fall, stratified surge and pyroclastic flow deposits. Furthermore statistical analysis made it possible to correlate pyroclastic flow and surge deposits interbedded with fall, interpreted as a lateral facies variation. Finally, the passage from magmatic to hydromagmatic activity is marked by the deposition of pyroclastic flow, surge and accretionary lapilli-bearing deposits. No transitional phase from magmatic to hydromagmatic activity has been recognized.

Determining the order of deposition of natural latent fingerprints and laser printed ink using chemical mapping with secondary ion mass spectrometry.

PubMed

Attard Montalto, Nicola; Ojeda, Jesús J; Jones, Benjamin J

2013-03-01

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) chemical mapping was used to investigate the order of deposition of natural latent fingerprints and laser printed ink on paper. This feasibility study shows that sodium, potassium and C(3)H(5) positive ions were particularly abundant endogenous components of the natural fingerprints and also present in the paper examined, but were mostly absent in the laser printed ink. Mapping of these ions enables the observation of friction ridges from latent prints on the ink surface, only when a fingerprint was deposited above the layer of ink. As a demonstration of proof of concept, blind testing of 21 samples from three donors resulted in a 100% success rate. The sensitivity of this technique was investigated within this trial through the examination of up to fifth depletion fingerprints and ageing of up to 28 days. Migration of fingerprint and paper components to the ink surface, although observed with increased ageing time, was not found to compromise determination of the deposition sequence. Copyright © 2012. Published by Elsevier Ireland Ltd.

Predicted sequence of cortical tau and amyloid-β deposition in Alzheimer disease spectrum.

PubMed

Cho, Hanna; Lee, Hye Sun; Choi, Jae Yong; Lee, Jae Hoon; Ryu, Young Hoon; Lee, Myung Sik; Lyoo, Chul Hyoung

2018-04-17

We investigated sequential order between tau and amyloid-β (Aβ) deposition in Alzheimer disease spectrum using a conditional probability method. Two hundred twenty participants underwent 18 F-flortaucipir and 18 F-florbetaben positron emission tomography scans and neuropsychological tests. The presence of tau and Aβ in each region and impairment in each cognitive domain were determined by Z-score cutoffs. By comparing pairs of conditional probabilities, the sequential order of tau and Aβ deposition were determined. Probability for the presence of tau in the entorhinal cortex was higher than that of Aβ in all cortical regions, and in the medial temporal cortices, probability for the presence of tau was higher than that of Aβ. Conversely, in the remaining neocortex above the inferior temporal cortex, probability for the presence of Aβ was always higher than that of tau. Tau pathology in the entorhinal cortex may appear earlier than neocortical Aβ and may spread in the absence of Aβ within the neighboring medial temporal regions. However, Aβ may be required for massive tau deposition in the distant cortical areas. Copyright © 2018 Elsevier Inc. All rights reserved.

Late Pleistocene sequence architecture on the geostrophic current-dominated southwest margin of the Ulleung Basin, East Sea

NASA Astrophysics Data System (ADS)

Choi, Dong-Lim; Shin, Dong-Hyeok; Kum, Byung-Cheol; Jang, Seok; Cho, Jin-Hyung; Jou, Hyeong-Tae; Jang, Nam-Do

2018-06-01

High-resolution multichannel seismic data were collected to identify depositional sequences on the southwestern shelf of the Ulleung Basin, where a unidirectional ocean current is dominant at water depths exceeding 130 m. Four aggradational stratigraphic sequences with a 100,000-year cycle were recognized since marine isotope stage (MIS) 10. These sequences consist only of lowstand systems tracts (LSTs) and falling-stage systems tracts (FSSTs). Prograding wedge-shaped deposits are present in the LSTs near the shelf break. Oblique progradational clinoforms of forced regressive deposits are present in the FSSTs on the outer continental shelf. Each FSST has non-uniform forced regressional stratal geometries, reflecting that the origins of sediments in each depositional sequence changed when sea level was falling. Slump deposits are characteristically developed in the upper layer of the FSSTs, and this was used as evidence to distinguish the sequence boundaries. The subsidence rates around the shelf break reached as much as 0.6 mm/year since MIS 10, which contributed to the well-preserved depositional sequence. During the Quaternary sea-level change, the water depth in the Korea Strait declined and the intensity of the Tsushima Current flowing near the bottom of the inner continental shelf increased. This resulted in greater erosion of sediments that were delivered to the outer continental shelf, which was the main cause of sediment deposition on the deep, low-angled outer shelf. Therefore, a depositional sequence formation model that consists of only FSSTs and LSTs, excluding highstand systems tracts (HSTs) and transgressive systems tracts (TSTs), best explains the depositional sequence beneath this shelf margin dominated by a geostrophic current.

Late Pleistocene sequence architecture on the geostrophic current-dominated southwest margin of the Ulleung Basin, East Sea

NASA Astrophysics Data System (ADS)

Choi, Dong-Lim; Shin, Dong-Hyeok; Kum, Byung-Cheol; Jang, Seok; Cho, Jin-Hyung; Jou, Hyeong-Tae; Jang, Nam-Do

2017-11-01

High-resolution multichannel seismic data were collected to identify depositional sequences on the southwestern shelf of the Ulleung Basin, where a unidirectional ocean current is dominant at water depths exceeding 130 m. Four aggradational stratigraphic sequences with a 100,000-year cycle were recognized since marine isotope stage (MIS) 10. These sequences consist only of lowstand systems tracts (LSTs) and falling-stage systems tracts (FSSTs). Prograding wedge-shaped deposits are present in the LSTs near the shelf break. Oblique progradational clinoforms of forced regressive deposits are present in the FSSTs on the outer continental shelf. Each FSST has non-uniform forced regressional stratal geometries, reflecting that the origins of sediments in each depositional sequence changed when sea level was falling. Slump deposits are characteristically developed in the upper layer of the FSSTs, and this was used as evidence to distinguish the sequence boundaries. The subsidence rates around the shelf break reached as much as 0.6 mm/year since MIS 10, which contributed to the well-preserved depositional sequence. During the Quaternary sea-level change, the water depth in the Korea Strait declined and the intensity of the Tsushima Current flowing near the bottom of the inner continental shelf increased. This resulted in greater erosion of sediments that were delivered to the outer continental shelf, which was the main cause of sediment deposition on the deep, low-angled outer shelf. Therefore, a depositional sequence formation model that consists of only FSSTs and LSTs, excluding highstand systems tracts (HSTs) and transgressive systems tracts (TSTs), best explains the depositional sequence beneath this shelf margin dominated by a geostrophic current.

Lithofacies and sequence stratigraphic analysis of the Upper Jurassic siliciclastics in the eastern Kopet-Dagh Basin, NE Iran

NASA Astrophysics Data System (ADS)

Zand-Moghadam, Hamed; Moussavi-Harami, Reza; Mahboubi, Asadollah; Aghaei, Ali

2016-05-01

The Upper Jurassic (Oxfordian-Kimmeridgian) Mozduran Formation is the most important gas reservoirs of the northeast Iran. Siliciclastic facies of this formation in eastern most parts of the basin have not been studied yet. Therefore, four stratigraphic sections of Mozduran Formation have been selected in the Kole-Malekabad, Kale-Karab, Deraz-Ab and Karizak to interpret depositional history and analyze depositional sequences. Based on texture and sedimentary structures, 14 slilciclastic lithofacies were identified and classified into four categories, including conglomerate (Gms, Gp, Gt), sandstone (Sh, Sp, St, Sr, Sl, Sm, Se), mud rock (Fl) and intermediate sandstone-mud rock (Sr (Fl), Sr/Fl, Fl (Sr)). Identified lithofacies formed four architectural elements CH, SB, LA and FF. Lithofacies characteristics and architectural elements with mostly bimodal pattern of paleocurrents show that the majority of Mozduran lithofacies deposited in the coastal environment (tidal influence). Sequence stratigraphic analysis shows that the Kole-Malekabad section consists of two depositional sequences while other sections are characterized by three depositional sequences. The lower and upper sequence boundaries of the Mozduran Formation in all stratigraphic sections are SB1 that are distinguished by paleosol and sometime conglomerate horizons. Most of depositional sequences in studied sections are composed only of TST and HST. The TST deposits consist mostly of quartzarenite and litharenite petrofacies that have been deposited in the tidal zone. HST packages are mostly including mud rocks with interdeds of sandstone lithofacies that are deposited in supratidal setting. The LST facies is recognized only in the DS3 (equivalent to the second depositional sequences of the Kole-Malekabad), which consist of conglomerate facies. Instead, the Kole-Malekabad section is often composed of supratidal gypsiferrous shales, indicating sea level fall in the study area.

Facies analysis, diagenesis and sequence stratigraphy of the carbonate-evaporite succession of the Upper Jurassic Surmeh Formation: Impacts on reservoir quality (Salman Oil Field, Persian Gulf, Iran)

NASA Astrophysics Data System (ADS)

Beigi, Maryam; Jafarian, Arman; Javanbakht, Mohammad; Wanas, H. A.; Mattern, Frank; Tabatabaei, Amin

2017-05-01

This study aims to determine the depositional facies, diagenetic processes and sequence stratigraphic elements of the subsurface carbonate-evaporite succession of the Upper Jurassic (Kimmeridgian-Tithonian) Surmeh Formation of the Salman Oil Field (the Persian Gulf, Iran), in an attempt to explore their impacts on reservoir quality. The Surmeh Formation consists mainly of carbonate rocks, intercalated with evaporite layers. Petrographically, the Surmeh Formation consists of nine microfacies (MF1-MF9). These microfacies are grouped into three facies associations related to three depositional environments (peritidal flat, lagoon and high-energy shoal) sited on the inner part of a homoclinal carbonate ramp. The recorded diagenetic processes include dolomitization, anhydritization, compaction, micritization, neomorphism, dissolution and cementation. Vertical stacking patterns of the studied facies reveal the presence of three third-order depositional sequences, each of which consists of transgressive systems tract (TST) and highstand systems tract (HST). The TSTs comprise intertidal and lagoon facies whereas the HSTs include supratidal and shoal facies. In terms of their impacts on reservoir quality, the shoal facies represent the best reservoir quality, whereas the peritidal and lagoonal facies exhibit moderate to lowest reservoir quality. Also, poikilotopic anhydrite cement played the most significant role in declining the reservoir quality, whereas the widespread dissolution of labile grains and formation of moldic and vuggy pores contributed in enhancing the reservoir quality. In addition, the HSTs have a better reservoir quality than the TSTs. This study represents an approach to use the depositional facies, diagenetic alterations and sequence stratigraphic framework of carbonate -evaporite succession for a more successful reservoir characterization.

Paleocene-eocene lignite beds of southwest Alabama: Parasequence beds in highstand systems tracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mancini, E.A.; Tew, B.H.; Carroll, R.E.

1993-09-01

In southwest Alabama, lignite beds are present in at least four stratigraphic intervals that span approximately 8 m.y. of geologic time. Lignite is found in the Paleocene Oak Hill Member and Coal Bluff Member of the Naheola Formation of the Midway Group and the Paleocene Tuscahoma Sand and the Eocene Hatchetigbee Formation of the Wilcox Group. Lignite beds range in thickness from 0.5 to 11 ft and consist of 32-53% moisture, 13-39% volatile matter, 4-36% fixed carbon, and 5-51% ash. These Paleocene and Eocene lignite beds occur as parasequence deposits in highstand systems tracts of four distinct third-order depositional sequences.more » The lignite beds are interpreted as strata within highstand systems tract parasequences that occur in mud-dominated regressive intervals. Lignite beds were deposited in coastal marsh and low-lying swamp environments as part of deltaic systems that prograded into southwestern Alabama from the west. As sediment was progressively delivered into the basin from these deltas, the effects of relative sea level rise during an individual cycle were overwhelmed, producing a net loss of accommodation and concomitant overall basinward progradation of the shoreline (regression). Small-scale fluctuations in water depth resulting from the interaction of eustasy, sediment yield, and subsidence led to cyclical flooding of the low-lying coastal marshes and swamps followed by periods of progradational and regression. Highstand systems tract deposition within a particular depositional sequence culminated with a relative sea level fall that resulted in a lowering of base level and an abrupt basinward shift in coastal onlap. Following sea level fall and the subsequent accumulation of the lowstand deposits, significant relative sea level rise resulted in the marine inundation of the area previously occupied by coastal marshes and swamps and deposition of the transgressive systems tract of the overlying sequence.« less

Phylogenetic diversity and biogeography of the Mamiellophyceae lineage of eukaryotic phytoplankton across the oceans.

PubMed

Monier, Adam; Worden, Alexandra Z; Richards, Thomas A

2016-08-01

High-throughput diversity amplicon sequencing of marine microbial samples has revealed that members of the Mamiellophyceae lineage are successful phytoplankton in many oceanic habitats. Indeed, these eukaryotic green algae can dominate the picoplanktonic biomass, however, given the broad expanses of the oceans, their geographical distributions and the phylogenetic diversity of some groups remain poorly characterized. As these algae play a foundational role in marine food webs, it is crucial to assess their global distribution in order to better predict potential changes in abundance and community structure. To this end, we analyzed the V9-18S small subunit rDNA sequences deposited from the Tara Oceans expedition to evaluate the diversity and biogeography of these phytoplankton. Our results show that the phylogenetic composition of Mamiellophyceae communities is in part determined by geographical provenance, and do not appear to be influenced - in the samples recovered - by water depth, at least at the resolution possible with the V9-18S. Phylogenetic classification of Mamiellophyceae sequences revealed that the Dolichomastigales order encompasses more sequence diversity than other orders in this lineage. These results indicate that a large fraction of the Mamiellophyceae diversity has been hitherto overlooked, likely because of a combination of size fraction, sequencing and geographical limitations. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Depositional facies, environments and sequence stratigraphic interpretation of the Middle Triassic-Lower Cretaceous (pre-Late Albian) succession in Arif El-Naga anticline, northeast Sinai, Egypt

NASA Astrophysics Data System (ADS)

El-Azabi, M. H.; El-Araby, A.

2005-01-01

The Middle Triassic-Lower Cretaceous (pre-Late Albian) succession of Arif El-Naga anticline comprises various distinctive facies and environments that are connected with eustatic relative sea-level changes, local/regional tectonism, variable sediment influx and base-level changes. It displays six unconformity-bounded depositional sequences. The Triassic deposits are divided into a lower clastic facies (early Middle Triassic sequence) and an upper carbonate unit (late Middle- and latest Middle/early Late Triassic sequences). The early Middle Triassic sequence consists of sandstone with shale/mudstone interbeds that formed under variable regimes, ranging from braided fluvial, lower shoreface to beach foreshore. The marine part of this sequence marks retrogradational and progradational parasequences of transgressive- and highstand systems tract deposits respectively. Deposition has taken place under warm semi-arid climate and a steady supply of clastics. The late Middle- and latest Middle/early Late Triassic sequences are carbonate facies developed on an extensive shallow marine shelf under dry-warm climate. The late Middle Triassic sequence includes retrogradational shallow subtidal oyster rudstone and progradational lower intertidal lime-mudstone parasequences that define the transgressive- and highstand systems tracts respectively. It terminates with upper intertidal oncolitic packstone with bored upper surface. The next latest Middle/early Late Triassic sequence is marked by lime-mudstone, packstone/grainstone and algal stromatolitic bindstone with minor shale/mudstone. These lower intertidal/shallow subtidal deposits of a transgressive-systems tract are followed upward by progradational highstand lower intertidal lime-mudstone deposits. The overlying Jurassic deposits encompass two different sequences. The Lower Jurassic sequence is made up of intercalating lower intertidal lime-mudstone and wave-dominated beach foreshore sandstone which formed during a short period of rising sea-level with a relative increase in clastic supply. The Middle-Upper Jurassic sequence is represented by cycles of cross-bedded sandstone topped with thin mudstone that accumulated by northerly flowing braided-streams accompanying regional uplift of the Arabo-Nubian shield. It is succeeded by another regressive fluvial sequence of Early Cretaceous age due to a major eustatic sea-level fall. The Lower Cretaceous sequence is dominated by sandy braided-river deposits with minor overbank fines and basal debris flow conglomerate.

Sequence architecture of the Palaeocene Transitional Facies and Response to Tectonic Evolution and Sea Level Change in the Lishui Depression, East China Sea

NASA Astrophysics Data System (ADS)

Li, D.

2016-12-01

The Lishui Depression (LD) is a polycyclic rift basin located in the southwestern of the East China Sea Shelf Basin. From bottom to top, the Palaeocene strata sequentially comprise the Yueguifeng (YGF), Lingfeng (LF) and Mingyuefeng Formations (MYF). The YGF clastic deposits were produced by a continental lacustrine. The LF and MYF were a set of coal-bearing strata formed by marine transgressive-regressive cycles. The Palaeocene depositional cycle is divided into two second-order sequences, namely SQII1 (YGF, 66.5-60Ma) and SQII2 (LF and MYF, 60-53Ma), which can be interpreted as the initial rifting sequence and the strong rifting sequence respectively that controlled by episodic tectonic subsidence, namely Yandang and Oujiang movements. The SQII1 includes only one third-order sequence, namely SQIII1, which is constituted by lake transgressive systems tract (LTST) and lake regressive systems tract (LRST). The SQII2 can be subdivided into four third-order sequences, namely SQIII2 (Lower LF, 60-57Ma), SQIII3 (Upper LF, 57-55Ma), SQIII4 (Lower MYF, 55-54.5Ma) and SQIII5 (Upper MYF, 54.5-53Ma). In the SQIII2 period, LD suffered massive transgression and the sustained high relative sea level led to the only development of transgressive systems tract (TST) and highstand systems tract (HST). In the SQIII3 period, the relative sea level declined and simultaneously two sets of incised valley were recognized on the seismic reflection with no lowstand fan developed. So the SQIII3 is considered to be composed of basin margin systems tract (BMST, similar to the shelf margin systems tract), TST and HST. Early SQIII4 (55Ma ), the relative sea level started global rapid declining and the LST of LD developed a completed system of prograding wedge, incised valley and basin floor fan. While the TST developed a retrograding marine sediments and the HST was characterized by a typical foreset parasequences. In SQIII5 period, the global sea level continuously rose and the sedimentary cycle of LD was only composed of TST and HST.

Rock avalanches clusters along the northern Chile coastal scarp

NASA Astrophysics Data System (ADS)

Crosta, G. B.; Hermanns, R. L.; Dehls, J.; Lari, S.; Sepulveda, S.

2017-07-01

Rock avalanche clusters can be relevant indicators of the evolution of specific regions. They can be used to define: the type and intensity of triggering events, their recurrence and potential probability of occurrence, the progressive damage of the rock mass, the mechanisms of transport and deposition, as well as the environmental conditions at the time of occurrence. This paper tackles these subjects by analyzing two main clusters of rock avalanches (each event between 0.6 and 30 Mm3), separated by few kilometers and located along the coastal scarp of Northern Chile, south of Iquique. It lies, hence, within a seismic area characterized by a long seismic gap that ended on April 1st, 2014 with a Mw 8.2 earthquake. The scar position, high along the coastal cliff, supports seismic triggering for these clusters. The deposits' relative positions are used to obtain the sequence of rock avalanching events for each cluster. The progressive decrease of volume in the sequence of rock avalanches forming each cluster fits well the theoretical models for successive slope failures. These sequences seem to agree with those derived by dating the deposits with ages spanning between 4 kyr and 60 kyr. An average uplift rate of 0.2 mm/yr in the last 40 kyr is estimated for the coastal plain giving a further constraint to the rock avalanche deposition considering the absence of reworking of the deposits. Volume estimates and datings allow the estimation of an erosion rate contribution of about 0.098-0.112 mm km- 2 yr- 1 which is well comparable to values presented in the literature for earthquake induced landslides. We have carried out numerical modeling in order to analyze the mobility of the rock avalanches and examine the environmental conditions that controlled the runout. In doing so, we have considered the sequence of individual rock avalanches within the specific clusters, thus including in the models the confining effect caused by the presence of previous deposits. Bingham rheology was the most successful at explaining both the distance and the geometry of the observed events.

Moonshine Versus Earthshine: Physics Makes a Difference

NASA Technical Reports Server (NTRS)

Wilson, T. L.

2005-01-01

Introduction: Recently released, high-resolution images from the Mars Orbiter Camera (MOC) and the Thermal Emission Imaging System (THEMIS) reveal a myriad of intriguing landforms banked along the northern edge of Terby Crater located on the northern rim of Hellas (approx.28degS, 287degW). Landforms within this crater include north-trending troughs and ridges, a remarkable 2.5 km-thick sequence of exposed layers, mantled ramps that extend across and between layered sequences, fan-like structures, sinuous channels, collapse pits, a massive landslide and viscous flow features. The suite of diverse landforms in Terby and its immediate surroundings attest to a diversity of rock types and geologic processes, making this locality ideal for studying landform-climate relationships on Mars. In order to decipher the complicated geologic history of Terby Crater and the nature of the layered deposits, a generalized geomorphic map was created and the slope of the layered deposits was examined.

Reconstruction of the sediment flow regime in a semi-arid Mediterranean catchment using check dam sediment information.

NASA Astrophysics Data System (ADS)

Bussi, G.; Rodríguez, X.; Francés, F.; Benito, G.; Sánchez-Moya, Y.; Sopeña, A.

2012-04-01

When using hydrological and sedimentological models, lack of historical records is often one of the main problems to face, since observed data are essential for model validation. If gauged data are poor or absent, a source of additional proxy data may be the slack-water deposits accumulated in check dams. The aim of this work is to present the result of the reconstruction of the recent hydrological and sediment yield regime of a semi-arid Mediterranean catchment (Rambla del Poyo, Spain, 184 square km) by coupling palaeoflood techniques with a distributed hydrological and sediment cycle model, using as proxy data the sandy slack-water deposits accumulated upstream a small check dam (reservoir volume 2,500 square m) located in the headwater basin (drainage area 13 square km). The solid volume trapped into the reservoir has been estimated using differential GPS data and an interpolation technique. Afterwards, the total solid volume has been disaggregated into various layers (flood units), by means of a stratigraphical description of a depositional sequence in a 3.5 m trench made across the reservoir sediment deposit, taking care of identifying all flood units; the separation between flood units is indicated by a break in deposition. The sedimentary sequence shows evidence of 15 flood events that occurred after the dam construction (early '90). Not all events until the present are included; for the last ones, the stream velocity and energy conditions for generating slack-water deposits were not fulfilled due to the reservoir filling. The volume of each flood unit has been estimated making the hypothesis that layers have a simple pyramidal shape (or wedge); every volume represents an estimation of the sediments trapped into the reservoir corresponding to each flood event. The obtained results have been compared with the results of modeling a 20 year time series (1990 - 2009) with the distributed conceptual hydrological and sediment yield model TETIS-SED, in order to assign a date to every flood unit. The TETIS-SED model provides the sediment yield series divided into textural fractions (sand, silt and clay). In order to determine the amount of sediments trapped into the ponds, trap efficiency of each check dam is computed by using the STEP model (Sediment Trap Efficiency model for small Ponds, Verstraeten and Poesen, 2001). Sediment dry bulk density is calculated according to Lane and Koelzer (1943) formulae. In order to improve the reliability of the flood reconstruction, distributed historical fire data has also been used for dating carbon layers found in the depositional sequence. Finally, a date has been assigned to every flood unit, corresponding to an extreme rainfall event; the result is a sediment volume series from 1990 to 2009, which may be very helpful for validating both hydrological and sediment yield models and can improve our understanding on erosion and sediment yield in this catchment.

PipeOnline 2.0: automated EST processing and functional data sorting.

PubMed

Ayoubi, Patricia; Jin, Xiaojing; Leite, Saul; Liu, Xianghui; Martajaja, Jeson; Abduraham, Abdurashid; Wan, Qiaolan; Yan, Wei; Misawa, Eduardo; Prade, Rolf A

2002-11-01

Expressed sequence tags (ESTs) are generated and deposited in the public domain, as redundant, unannotated, single-pass reactions, with virtually no biological content. PipeOnline automatically analyses and transforms large collections of raw DNA-sequence data from chromatograms or FASTA files by calling the quality of bases, screening and removing vector sequences, assembling and rewriting consensus sequences of redundant input files into a unigene EST data set and finally through translation, amino acid sequence similarity searches, annotation of public databases and functional data. PipeOnline generates an annotated database, retaining the processed unigene sequence, clone/file history, alignments with similar sequences, and proposed functional classification, if available. Functional annotation is automatic and based on a novel method that relies on homology of amino acid sequence multiplicity within GenBank records. Records are examined through a function ordered browser or keyword queries with automated export of results. PipeOnline offers customization for individual projects (MyPipeOnline), automated updating and alert service. PipeOnline is available at http://stress-genomics.org.

Sequence stratigraphy, sedimentary systems and petroleum plays in a low-accommodation basin: Middle to upper members of the Lower Jurassic Sangonghe Formation, Central Junggar Basin, Northwestern China

NASA Astrophysics Data System (ADS)

Feng, Youliang; Jiang, Shu; Wang, Chunfang

2015-06-01

The Lower Jurassic Junggar Basin is a low-accommodation basin in northwestern China. Because of low subsidence rates and a warm, wet climate, deposits of the Central subbasin of the Junggar Basin formed from fluvial, deltaic, shallow lake facies. Sequence stratigraphy and sedimentary systems of the Lower Jurassic members of the Sangonghe Formation (J1s) were evaluated by observing cores, interpreting wireline logs and examining seismic profiles. Two third-order sequences were recognized in the strata. The distribution of the sedimentary systems in the systems tracts shows that tectonic movement, paleorelief, paleoclimate and changes in lake level controlled the architecture of individual sequences. During the development of the lowstand systems tract (LST), the intense structural movement of the basin resulted in a significant fall in the water level in the lake, accompanied by rapid accommodation decrease. Braided rivers and their deltaic systems were also developed in the Central Junggar Basin. Sediments carried by braided rivers were deposited on upward slopes of the paleorelief, and braid-delta fronts were deposited on downward slopes. During the transgressive systems tract (TST), the tectonic movement of the basin was quiescent and the climate was warm and humid. Lake levels rose and accommodation increased quickly, shoal lines moved landward, and shore- to shallow-lake deposits, sublacustrine fans and deep-lake facies were deposited in shallow- to deep-lake environments. During the highstand systems tract (HST), the accommodation no longer increased but sediment supply continued, far exceeding accommodation. HST deposits slowly formed in shallow-lake to meandering river delta-front environments. Relatively low rates of structural subsidence and low accommodation resulted in coarse-grained successions that were fining upward. Deposits were controlled by structural movement and paleorelief within the LST to TST deposits in the Central subbasin. Fine- to medium-grained coarsening-upward successions developed during the HST. The sand bodies of braid-delta fronts on the downward slopes of the paleorelief in the LST and the sublacustrine fans in the TST became reservoirs for hydrocarbon accumulation. Petroleum plays have only been found in the Sangonghe Formation (J1s) located on structural ridges that consist of sand bodies comprising these sequences. Favorable conditions for petroleum plays in HST1-LST2 occur where the sand bodies have been fractured by faults and sealed by denudation and pinch-out lines, then overlain by deep lake mudstone in TST2. The favorable condition of the sand bodies within TST2 occurs where isolated sand bodies have been fractured by faults.

A new stratigraphic model for the deposition of the Dammam Formation

NASA Astrophysics Data System (ADS)

Lokier, Stephen; Fiorini, Flavia; Min, Jina

2017-04-01

In recent years, mixed siliciclastic-carbonate successions have increasingly become targets for hydrocarbon exploration and production activities. Despite the abundance of these successions throughout the Middle East, there have been very few attempts to employ quantitative techniques to interpret their depositional settings and to develop constrained sequence stratigraphic models for their deposition. This study focuses on the Eocene age Dammam Formation that crops out on the flanks of the Jebel Hafeet anticline south of Al Ain in the United Arab Emirates. The Dammam Formation comprises units alternating between poorly-lithified, easily-weathered, siliciclastic and marly horizons and well-lithified limestones. These units were deposited in a foreland basin that formed in association with the Late Cretaceous obduction of the Semail Ophiolite onto the northeastern margin of the Arabian Plate. The Paleogene infilling of this basin is recorded in the shallowing-upward sedimentary sequence of the lithologies of the Pabdeh Group. This succession records the transition from marine carbonate sedimentation, through increasingly evaporitic-dominated units during the late Eocene to early Miocene to a fluvial-alluvial system by mid to late Miocene times. The Dammam Formation was deposited in an open shallow-marine setting strongly influenced by the influx of siliciclastic material sourced from the close-by uplifted massif of the obducted ophiolite. The skeletal assemblage of the Dammam Formation is dominated by Nummulites and Assilina larger benthic foraminifera along with subordinate smaller foraminifera, echinoids, bivalves, corals, bryozoan, gastropods, echinoids and calcareous algae. Previous studies of the Dammam Formation have employed the biotic component in the reconstruction of water depth. However, these studies neglected to consider that turbidity, associated with the abundant siliciclastic component, resulted in a reduction in the depth of the euphotic zone and a consequent response of the benthic biota. We employ a range of quantitative analytical techniques in order to constrain the influence of the siliciclastic component on the lithofacies of the Dammam Formation and present a new sequence stratigraphic model for the deposition of the formation.

Paleoseismology of a possible fault scarp in Wenas Valley, central Washington

USGS Publications Warehouse

Sherrod, Brian L.; Barnett, Elizabeth A.; Knepprath, Nichole; Foit, Franklin F.

2013-01-01

In October 2009, two trenches excavated across an 11-kilometer-long scarp at Wenas Valley in central Washington exposed evidence for late Quaternary deformation. Lidar imagery of the Wenas Valley illuminated the west-northwest-trending, 2- to 8-meter-high scarp as it bisected alluvial fans developed at the mouths of canyons along the south side of Umtanum Ridge. The alignment of the scarp and aeromagnetic lineaments suggested that the scarp may be a product of and controlled by the same tectonic structure that produced the magnetic lineaments. Several large landslides mapped in the area demonstrated the potential for large mass-wasting events in the area. In order to test whether the scarp was the result of an earthquake-generated surface rupture or a landslide, trenches were excavated at Hessler Flats and McCabe Place. The profiles of bedrock and soil stratigraphy that underlie the scarp in each trench were photographed, mapped, and described, and a sequence of depositional and deformational events established for each trench. The McCabe Place trench exposed a sequence of volcaniclastic deposits overlain by soils and alluvial deposits separated by three unconformities. Six normal faults and two possible reverse faults deformed the exposed strata. Crosscutting relations indicated that up to five earthquakes occurred on a blind reverse fault, and a microprobe analysis of lapilli suggested that the earliest faulting occurred after 47,000 years before present. The Hessler Flat trench exposure revealed weathered bedrock that abuts loess and colluvium deposits and is overlain by soil, an upper sequence of loess, and colluvium. The latter two units bury a distinctive paloesol.

Eustatic and tectonic control of deposition of the lower and middle Pennsylvanian strata of the Central Appalachian Basin

USGS Publications Warehouse

Chesnut, D.R.

1997-01-01

Stratigraphic analysis of Lower and Middle Pennsylvanian rocks of part of the Central Appalachian Basin reveals two orders of cycles and one overall trend in the vertical sequence of coal-bearing rocks. The smallest order cycle, the coal-clastic cycle, begins at the top of a major-resource coal bed and is composed of a vertical sequence of shale, siltstone, sandstone, seat rock, and overlying coal, which, in turn, is overlain by the next coal-clastic sequence. The average duration of the coal-clastic cycle has been calculated to be about 0.4 m.y. The major marine-transgression cycle is composed of five to seven coal-clastic cycles and is distinguished by the occurrence of widespread, relatively thick (generally thicker than 5 m) marine strata at its base. The duration of this cycle has been calculated to be about 2.5 m.y. The Breathitt coarsening-upward trend describes the general upward coarsening of the Middle Pennsylvanian part of the Breathitt Group. The Breathitt Group includes eight major marine-transgression cycles, and was deposited during a period of approximately 20 m.y. The average duration of coal-clastic cycles is of the same order of magnitude (105 year) as the Milankovitch orbital-eccentricity cycles, and matches the 0.4 m.y. second-order eccentricity cycle (Long Earth-Eccentricity cycle). These orbital periodicities are thought to modulate glacial stages and glacio-eustatic levels. The calculated periodicities of the coal-clastic cycles can be used as evidence for glacio-eustatic control of the coal-bearing rocks of the Appalachian Basin. The 2.5-m.y. periodicity of the major marine-transgression cycle does not match any known orbital or tectonic cycle; the cause of this cycle is unknown, but it might represent episodic thrusting in the orogen, propagation of intraplate stresses, or an unidentified orbital cycle. The Breathitt coarsening-upward trend is interpreted to represent the increasing intensity and proximity of the Alleghenian Orogeny. Previously, tectonic subsidence of the basin was considered to be the dominant control on deposition of the coal-bearing rocks of the basin. However, new calculations show that eustatic rates are more significant than averaged subsidence rates for the Pennsylvanian Appalachian Basin. Accordingly, sea-level changes are considered to be a dominant control on coastal sedimentation during the Pennsylvanian. However, tectonic subsidence created the accomodation space for preservation of various orders of cyclic sedimentation; the preserved order of cycles was dependent upon the rate of subsidence from basin margin to axis.

A topology of mineralization and its meaning for prospecting

USGS Publications Warehouse

Neuerburg, G.J.

1982-01-01

Epigenetic mineral deposits are universal members of an orderly spatial and temporal arrangement of igneous rocks, endomorphic rocks, and hydrothermally altered rocks. The association and sequence of these rocks is invariant whereas the metric relations and configurations of the properties of these rocks are unlimited in variety. This characterization satisfies the doctrines of topology. Metric relations are statistical, and their modes are among the better guides to optimal areas for exploration. Metric configurations are graphically irregular and unpredictable mathematical surfaces like mountain topography. Each mineral edifice must be mapped to locate its mineral deposits. All measurements and observations are only positive or neutral for the occurrence of a mineral deposit. Effective prospecting is based on an increasing density of positive data with proximity to the mineral deposit. This means sampling for maximal numbers of positive data, pragmatically the highest ore-element assays at each site, by selecting rock showing maximal development of lode attributes.

High-resolution sedimentological and subsidence analysis of the Late Neogene, Pannonian Basin, Hungary

USGS Publications Warehouse

Juhasz, E.; Muller, P.; Toth-Makk, A.; Hamor, T.; Farkas-Bulla, J.; Suto-Szentai, M.; Phillips, R.L.; Ricketts, B.

1996-01-01

Detailed sedimentological and paleontological analyses were carried out on more than 13,000 m of core from ten boreholes in the Late Neogene sediments of the Pannonian Basin, Hungary. These data provide the basis for determining the character of high-order depositional cycles and their stacking patterns. In the Late Neogene sediments of the Pannonian Basin there are two third-order sequences: the Late Miocene and the Pliocene ones. The Miocene sequence shows a regressive, upward-coarsening trend. There are four distinguishable sedimentary units in this sequence: the basal transgressive, the lower aggradational, the progradational and the upper aggradational units. The Pliocene sequence is also of aggradational character. The progradation does not coincide in time in the wells within the basin. The character of the relative water-level curves is similar throughout the basin but shows only very faint similarity to the sea-level curve. Therefore, it is unlikely that eustasy played any significant role in the pattern of basin filling. Rather, the dominant controls were the rapidly changing basin subsidence and high sedimentation rates, together with possible climatic factors.

Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin

NASA Astrophysics Data System (ADS)

Nehyba, Slavomír

2018-02-01

Two coarse-grained Gilbert-type deltas in the Lower Badenian deposits along the southern margin of the Western Carpathian Foredeep (peripheral foreland basin) were newly interpreted. Facies characterizing a range of depositional processes are assigned to four facies associations — topset, foreset, bottomset and offshore marine pelagic deposits. The evidence of Gilbert deltas within open marine deposits reflects the formation of a basin with relatively steep margins connected with a relative sea level fall, erosion and incision. Formation, progradation and aggradation of the thick coarse-grained Gilbert delta piles generally indicate a dramatic increase of sediment supply from the hinterland, followed by both relatively continuous sediment delivery and an increase in accommodation space. Deltaic deposition is terminated by relatively rapid and extended drowning and is explained as a transgressive event. The lower Gilbert delta was significantly larger, more areally extended and reveals a more complicated stratigraphic architecture than the upper one. Its basal surface represents a sequence boundary and occurs around the Karpatian/Badenian stratigraphic limit. Two coeval deltaic branches were recognized in the lower delta with partly different stratigraphic arrangements. This different stratigraphic architecture is mostly explained by variations in the sediment delivery and /or predisposed paleotopography and paleobathymetry of the basin floor. The upper delta was recognized only in a restricted area. Its basal surface represents a sequence boundary probably reflecting a higher order cycle of a relative sea level rise and fall within the Lower Badenian. Evidence of two laterally and stratigraphically separated coarse-grained Gilbert deltas indicates two regional/basin wide transgressive/regressive cycles, but not necessarily of the same order. Provenance analysis reveals similar sources of both deltas. Several partial source areas were identified (Mesozoic carbonates of the Northern Calcareous Alps and the Western Carpathians, crystalline rocks of the eastern margin of the Bohemian Massif, older sedimentary infill of the Carpathian Foredeep and/or the North Alpine Foreland Basin, sedimentary rocks of the Western Carpathian/Alpine Flysch Zone).

Sequence stratigraphy of the Triassic in the Barentsz Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skjold, L.JU.; Van Veen, P.M.; Gjelberg, J.

1990-05-01

A regional study of the Triassic in the Barentsz Sea (20-32{degree}E, 71-74{degree}N) revealed sequences that correlate seismically for hundreds of kilometers. Recent offshore drilling results enabled them to establish a biostratigraphic time framework. Comparisons with information from onshore outcrops (such as the Svalbard Archipelago) aided the piecing together of these superregional sequences. Seismic character analysis identified three units with composite progradational patterns (Induan, Olenekian, and Anisian). Fluvial, deltaic, and marine deposits can be distinguished and located relative to the paleocoastlines. Corresponding downlap surfaces suggest the development of condensed intervals, predicted to consist of organic-rich source rocks, as was later confirmedmore » by drilling. Regional predictions based on this sequence-stratigraphic approach have proved valuable when correlating and evaluating well information. The sequences identified also help define third-order sea level curves for the area; these improve published curves thought to have global significance.« less

MR Fingerprinting Using The Quick Echo Splitting NMR Imaging Technique

PubMed Central

Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A.

2016-01-01

Purpose The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining Magnetic Resonance Fingerprinting (MRF) technique with Quick Echo Splitting NMR Imaging Technique (QUEST). Methods A QUEST-based MRF sequence was implemented to acquire high order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T1 and T2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The SAR of QUEST-MRF was compared to the clinically available methods. Results MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head Specific Absorption Rate (SAR) of 0.03 W/kg. T1 and T2 values estimated by MRF-QUEST are in good agreement with the traditional methods. Conclusion The combination of the MRF and the QUEST provides an accurate quantification of T1 and T2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. PMID:26924639

Stratigraphy of Pyroclastic Deposits of EL Aguajito Caldera, Baja California Sur, MÉXICO

NASA Astrophysics Data System (ADS)

Osorio Ocampo, L. S.; Macias, J. L.; García Sánchez, L.; Pola, A.; Saucedo, R.; Sánchez, J. M.; Avellán, D. R.; Cardona, S.; Reyes-Agustín, G.; Arce, J. L.

2015-12-01

El Aguajito caldera is located in the State of Baja California Sur, it comprises an area of 450 km2 and sits within the Santa Rosalía Basin which is controlled by NE-SW extensional structures and the NW-SE Cimarron Fault that transects the caldera structure. The oldest rocks are ~90 Ma granodiorites covered by an Oligocene-Miocene volcano-sedimentary sequence, the Miocene Santa Lucia Formation and La Esperanza basalt. Pliocene volcanism is represented by La Reforma caldera, El Aguajito caldera, and the Tres Vírgenes Volcanic complex. This study focuses on the cartography and stratigraphy of area in order to understand the evolution of the volcanic system. The stratigraphy from base to top consists of a series of shallow marine sediments (fossiliferous sandstones) covered by a thick sequence of ignimbrites and pyroclastic flows interbedded with volcaniclastic deposits (Gloria and El Infierno Formations). On top of these deposits is El Aguajito caldera, it consists of a 2 m thick pumice fallout followed by an ignimbrite with three transitional lithofacies: a ≤30-m thick light-pink pyroclastic flow enriched in pumice at the base that gradually becomes enrich in lithics towards the top with the occurrence of degasing pipes. On top rests a 15 m-thick light-purple ignimbrite slightly welded with fiammes and a sequence of pumiceous pyroclastic flows and fallouts. These deposits have been associate to the caldera formation with a collapse diameter of ~8 km marked by rhyolitic domes exposed along a ring collapse crowned the sequence as well as NW-SE aligned rhyolitic domes parallel to the seashore. This cartography allowed to present a preliminary new geological map with four stratigraphic units recognized so far, that were emplaced under subaerial conditions beginning with a Plinian column followed by the emplacement of El Aguajito ignimbrite with its subsequent caldera collapse and finally the extrusion of resurgent domes.

Facies architecture and high resolution sequence stratigraphy of an aeolian, fluvial and shallow marine system in the Pennsylvanian Piauí Formation, Parnaíba Basin, Brazil

NASA Astrophysics Data System (ADS)

Vieira, Lucas Valadares; Scherer, Claiton Marlon dos Santos

2017-07-01

The Pennsylvanian Piauí Formation records the deposition of aeolian, fluvial and shallow marine systems accumulated in the cratonic sag Parnaíba basin. Characterization of the facies associations and sequence stratigraphic framework was done by detailed description and logging of outcrops. Six facies associations were recognized: aeolian dunes and interdunes, aeolian sandsheets, fluvial channels, tidally-influenced fluvial channels, shoreface and shoreface-shelf transition. Through correlation of stratigraphic surfaces, the facies associations were organized in system tracts, which formed eight high frequency depositional sequences, bounded by subaerial unconformities. These sequences are composed of a lowstand system tract (LST), that is aeolian-dominated or fluvial-dominated, a transgressive system tract (TST) that is formed by tidally-influenced fluvial channels and/or shoreface and shoreface-shelf transition deposits with retrogradational stacking, and a highstand system tract (HST), which is formed by shoreface-shelf transition and shoreface deposits with progradational stacking. Two low frequency cycles were determined by observing the stacking of the high frequency cycles. The Lower Sequence is characterized by aeolian deposits of the LST and an aggradational base followed by a progressive transgression, defining a general TST. The Upper Sequence is characterized by fluvial deposits and interfluve pedogenesis concurring with the aeolian deposits of the LST and records a subtle regression followed by transgression. The main control on sedimentation in the Piauí Formation was glacioeustasy, which was responsible for the changes in relative sea level. Even though, climate changes were associated with glacioeustatic phases and influenced the aeolian and fluvial deposition.

Stratigraphy of the Grande Savane Ignimbrite Sequence, Dominica, Lesser Antilles

NASA Astrophysics Data System (ADS)

Schneider, S.; Smith, A. L.; Deuerling, K.; Killingsworth, N.; Daly, G.

2007-12-01

The island of Dominica, located in the central part of the Lesser Antilles island arc has eight potentially active volcanoes. One of these, Morne Diablotins, is a composite stratovolcano with several superimposed stratigraphic sequences ranging in age from Pliocene (4-2 Ma) to "Younger" Pleistocene (<1.8 Ma). The most recent major eruptive activity from this volcano was a series of Plinian eruptions that produced ignimbrites that gave dates of >22,000 and >40,000 years B.P. The ignimbrite sequences form four flow fans that reached both the east and west coasts of the island. One of these flow fans, the Grande Savane, on the west coast of the island, also extends off-shore for a distance of at least 14 km as a distinctive submarine fan. Stratigraphical studies of the on- shore deposits that make up this fan indicate an older sequence of block and ash flow deposits, within which occurs a distinctive vulcanian fall deposit. These are overlain, with no evidence of an intervening paleosol, by a sequence of ignimbrites containing welded horizons (ranging in thickness from around 4 m to 16m). The lack of fall deposits beneath the ignimbrites suggest they may have been formed by instantaneous continuous collapse of the eruption column. This whole succession is overlain by a series of planar and dune bedded pumiceous surge deposits with interbedded pumiceous lapilli fall and ash fall deposits, that extend laterally outside of the main area of ignimbrite deposition. Beds within this upper sequence often contain accretionary lapilli and gas cavities suggesting magma-water interaction. The youngest deposits from Morne Diablotins appear to be valley- fill deposits of both ignimbrite and block and ash flow. A comparison of the of the Grande Savane pyroclastic sequence with the Pointe Ronde (west coast) and Londonderry (east coast) pyroclastic flow fans will provide information on the eruptive history of this major Plinian episode.

New Tertiary stratigraphy for the Florida Keys and southern peninsula of Florida

USGS Publications Warehouse

Cunningham, K.J.; McNeill, D.F.; Guertin, L.A.; Ciesielski, P.F.; Scott, T.M.; De Verteuil, L.

1998-01-01

Seven lithologic formations, ranging in age from Oligocene to Pleistocene, were recently penetrated by core holes in southernmost Florida. From bottom to top, they are the early Oligocene Suwannee Limestone; late-early Oligocene-to-Miocene Arcadia Formation, basal Hawthorn Group; late Miocene Peace River Formation, upper Hawthorn Group; newly proposed late Miocene-to-Pliocene Long Key and Stock Island Formations; and Pleistocene Key Largo and Miami Limestones. The rocks of the Suwannee Limestone form a third-order sequence. Although the entire thickness was not penetrated, 96 m of Suwannee core from one well contains at least 50 vertically stacked, exposure-capped limestone cycles, presumably related to rapid eustatic fluctuations while experiencing tropical to subtropical conditions. The Arcadia Formation is a composite sequence containing four high-frequency sequences composed of multiple vertically stacked carbonate cycles. Most cycles do not show evidence of subaerial exposure and were deposited under more temperate conditions, relative to the Suwannee Limestone. The Arcadia Formation in southernmost Florida is bounded by regional unconformities representing third-order sequence boundaries. Post-Arcadia transgression produced a major backstepping of sediment accumulation above the upper sequence boundary of the Arcadia Formation. The Peace River Formation, composed of diatomaceous mudstones, has been identified only beneath the Florida peninsula and is not present beneath the Florida Keys. Deposition occurred during marine transgressive to high-stand conditions and a local phosphatization event (recorded in northeast Florida). The transgression is possibly related to a global rise in sea level, which resulted in upwelling of relatively cooler, relatively nutrient-rich water masses onto the Florida Platform. It is proposed that the absence of Peace River sediments beneath the Keys is due to sediment bypass of the upper surface of the Arcadia, a result of sediment sweeping by an ancestral Florida current. During late Miocene to Pliocene time in the Florida Keys, siliciclastics of the Long Key Formation and fine-grained carbonates of the Stock Island Formation prograded toward the southern edge of the Florida Platform and downlapped onto the regional unconformity at the top of the Arcadia. Shallow-marine Pleistocene limestones (Key Largo and Miami Limestones), deposited during tropical to subtropical conditions, drape over accretionary successions of the Long Key and Stock Island Formations.

Hydrologic framework of Long Island, New York

USGS Publications Warehouse

Smolensky, Douglas A.; Buxton, Herbert T.; Shernoff, Peter K.

1990-01-01

Long Island, N.Y., is underlain by a mass of unconsolidated geologic deposits of clay, silt, sand, and gravel that overlie southward-sloping consolidated bedrock. These deposits are thinnest in northern Queens County (northwestern Long Island), where bedrock crops out, and increase to a maximum thickness of 2,000 ft in southeastern Long Island. This sequence of unconsolidated deposits consists of several distinct geologic units ranging in age from late Cretaceous through Pleistocene, with some recent deposits near shores and streams. These units are differentiated by age, depositional environment, and lithology in table 1. Investigations of ground-water availability and flow patterns may require information on the internal geometry of the hydrologic system that geologic correlations and interpretation alone cannot provide; hydrologic interpretations in which deposits are differentiated on the basis of water-transmitting properties are generally needed also. This set of maps and vertical sections depicts the hydrogeologic framework of the unconsolidated deposits that form Long Island's ground-water system. These deposits can be classified into eight major hydrogeologic units (table 1). The hydrogeologic interpretations presented herein are not everywhere consistent with strict geologic interpretation owing to facies changes and local variations in the water-transmitting properties within geologic units. These maps depict the upper-surface altitude of seven of the eight hydrogeologic units, which, in ascending order, are: consolidated bedrock, Lloyd aquifer, Raritan confining unit, Magothy aquifer, Monmouth greensand, Jameco aquifer, and Gardiners Clay. The upper glacial aquifer—the uppermost unit—is at land surface over most of Long Island and is, therefore, not included. The nine north-south hydrogeologic sections shown below depict the entire sequence of unconsolidated deposits and, together with the maps, provide a detailed three-dimensional interpretation of Long Island's hydrogeologic framework. The structure-contour map that shows the upper-surface altitude of the Cretaceous deposits is included to illustrate the erosional unconformity between the Cretaceous and overlying Pleistocene deposits. Pleistocene erosion played a major role in determining the shape and extent of the Lloyd aquifer, the Raritan confining unit, and the Magothy aquifer, and thus partly determined their hydrogeologic relation with subsequent (post-Cretaceous) deposits.

Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin

USGS Publications Warehouse

Browning, J.V.; Miller, K.G.; McLaughlin, P.P.; Edwards, L.E.; Kulpecz, A.A.; Powars, D.S.; Wade, B.S.; Feigenson, M.D.; Wright, J.D.

2009-01-01

The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy. Age is based primarily on Sr isotope stratigraphy supplemented by biostratigraphy (dinocysts, nannofossils, and planktonic foraminifers); age resolution is approximately ??0.5 Ma for early Miocene sequences and approximately ??1.0 Ma for younger and older sequences. Eocene-lower Miocene sequences are subtle, upper middle to lower upper Miocene sequences are more clearly distinguished, and upper Miocene- Pliocene sequences display a distinct facies pattern within sequences. We recognize two upper Eocene, two Oligocene, nine Miocene, three Pliocene, and one Pleistocene sequence and correlate them with those in New Jersey and Delaware. The upper Eocene through Pleistocene strata at Eyreville record changes from: (1) rapidly deposited, extremely fi ne-grained Eocene strata that probably represent two sequences deposited in a deep (>200 m) basin; to (2) highly dissected Oligocene (two very thin sequences) to lower Miocene (three thin sequences) with a long hiatus; to (3) a thick, rapidly deposited (43-73 m/Ma), very fi ne-grained, biosiliceous middle Miocene (16.5-14 Ma) section divided into three sequences (V5-V3) deposited in middle neritic paleoenvironments; to (4) a 4.5-Ma-long hiatus (12.8-8.3 Ma); to (5) sandy, shelly upper Miocene to Pliocene strata (8.3-2.0 Ma) divided into six sequences deposited in shelf and shoreface environments; and, last, to (6) a sandy middle Pleistocene paralic sequence (~400 ka). The Eyreville cores thus record the fi lling of a deep impact-generated basin where the timing of sequence boundaries is heavily infl uenced by eustasy. ?? 2009 The Geological Society of America.

Hydraulics of subaqueous ash flows as deduced from their deposits

NASA Astrophysics Data System (ADS)

Doronzo, Domenico M.; Dellino, Pierfrancesco

2012-09-01

Subaqueous ash flows are gravity currents consisting of a mixture of sea water and ash particles. Also called volcaniclastic turbidity currents (VTCs), they can be generated because of remobilization of pyroclastic fall deposits, which are emplaced into the sea around a volcanic island, as well as far away, during an explosive eruption. The VTC upper part is the turbulent transport system for the flow, whereas the viscous basal one is the depositional system. Typical sequences of VTC deposits are characterized by cross-laminations, planar and convolute laminations, and massive beds, which reflect the stratified nature of the flow. Here, the analysis of some VTC hydraulic parameters is presented in order to depict flow behavior and sedimentation during deposition. A reverse engineering approach is proposed, which consists of calculating hydraulic parameters by starting from deposit features. The calculated values show that a VTC is homogeneously-turbulent for most of the thickness, but is viscous at its base. First, cross-laminations are directly acquired over the rough pre-existing seafloor, then planar or convolute laminations aggrade over the newly formed substrate. Finally, fine-grained suspended particles gently settle and cap the flow deposit.

Sedimentology of the fluvial and fluvio-marine facies of the Bahariya Formation (Early Cenomanian), Bahariya Oasis, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Khalifa, M. A.; Catuneanu, O.

2008-05-01

The Lower Cenomanian Bahariya Formation in the Bahariya Oasis, Western Desert, Egypt, was deposited under two coeval environmental conditions. A fully fluvial system occurs in the southern portion of the Bahariya Oasis, including depositional products of meandering and braided streams, and a coeval fluvio-marine setting is dominant to the north. These deposits are organized into four unconformity-bounded depositional sequences, whose architecture is shaped by a complex system of incised valleys. The fluvial portion of the lower two depositional sequences is dominated by low-energy, meandering systems with a tabular geometry, dominated by overbank facies. The fluvial deposits of the upper two sequences represent the product of sedimentation within braided streams, and consist mainly of amalgamated channel-fills. The braided fluvial systems form the fill of incised valleys whose orientation follows a southeast-northwest trending direction, and which truncate the underlying sequences. Four sedimentary facies have been identified within the braided-channel systems, namely thin-laminated sandstones (Sh), cross-bedded sandstones (Sp, St), massive ferruginous sandstones (Sm) and variegated mudstones (Fm). The exposed off-channel overbank facies of the meandering systems include floodplain (Fm) and crevasse splay (Sl) facies. The fluvio-marine depositional systems consist of interbedded floodplain, coastal and shallow-marine deposits. The floodplain facies include fine-grained sandstones (Sf), laminated siltstones (Stf) and mudstones (Mf) that show fining-upward cycles. The coastal to shallow-marine facies consist primarily of mudstones (Mc) and glauconitic sandstones (Gc) organized vertically in coarsening-upward prograding cyclothems topped by thin crusts of ferricrete (Fc). The four depositional sequences are present across the Bahariya Oasis, albeit with varying degrees of preservation related to post-depositional erosion associated with the formation of sequence boundaries. These unconformities may be overlain by braided-stream channel sandstones at the base of incised valleys, or marked by ferricrete paleosols (lithofacies Fc) in the interfluve areas.

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMillen, K.J.; Do Van Luu; Lee, E.K.

1996-12-31

An integrated well log, biostratigraphic, and seismic stratigraphic study of Miocene to Recent deltaic sediments deposited in the Nam Con Son Basin offshore from southern Vietnam shows the influence of eustacy and tectonics on sequence development. Sediments consist of Oligocene non-marine rift-basin fill (Cau Formation), early to middle Miocene tide-dominated delta plain to delta front sediments (TB 1.5 to TB 2.5, Due and Thong Formations), and late Miocene to Recent marine shelf sediments (TB. 2.6 to TB 3.1 0, Mang Cau, Nam Con Son, and Bien Dong Formations). Eustacy controlled the timing of key surfaces and sand distribution in themore » tectonically-quiet early Miocene. Tectonic effects on middle to late Miocene sequence development consist of thick transgressive systems tracts due to basin-wide subsidence and transgression, sand distribution in the basin center, and carbonate sedimentation on isolated fault blocks within the basin. Third-order sequence boundaries (SB) are identified by spore peaks, sand stacking patterns, and channel incision. In the basin center, widespread shale beds with coal occur above sequence boundaries followed by transgressive sandstone units. These TST sandstones merge toward the basin margin where they lie on older HST sandstones. Maximum flooding surfaces (MFS) have abundant marine microfossils and mangrove pollen, a change in sand stacking pattern, and often a strong seismic reflection with downlap. Fourth-order genetic-type sequences are also interpreted. The MFS is the easiest marker to identify and correlate on well logs. Fourth-order SB occur within these genetic units but are harder to identify and correlate.« less

Neogene sequence stratigraphy, Nam Con Son Basin, offshore Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMillen, K.J.; Do Van Luu; Lee, E.K.

1996-01-01

An integrated well log, biostratigraphic, and seismic stratigraphic study of Miocene to Recent deltaic sediments deposited in the Nam Con Son Basin offshore from southern Vietnam shows the influence of eustacy and tectonics on sequence development. Sediments consist of Oligocene non-marine rift-basin fill (Cau Formation), early to middle Miocene tide-dominated delta plain to delta front sediments (TB 1.5 to TB 2.5, Due and Thong Formations), and late Miocene to Recent marine shelf sediments (TB. 2.6 to TB 3.1 0, Mang Cau, Nam Con Son, and Bien Dong Formations). Eustacy controlled the timing of key surfaces and sand distribution in themore » tectonically-quiet early Miocene. Tectonic effects on middle to late Miocene sequence development consist of thick transgressive systems tracts due to basin-wide subsidence and transgression, sand distribution in the basin center, and carbonate sedimentation on isolated fault blocks within the basin. Third-order sequence boundaries (SB) are identified by spore peaks, sand stacking patterns, and channel incision. In the basin center, widespread shale beds with coal occur above sequence boundaries followed by transgressive sandstone units. These TST sandstones merge toward the basin margin where they lie on older HST sandstones. Maximum flooding surfaces (MFS) have abundant marine microfossils and mangrove pollen, a change in sand stacking pattern, and often a strong seismic reflection with downlap. Fourth-order genetic-type sequences are also interpreted. The MFS is the easiest marker to identify and correlate on well logs. Fourth-order SB occur within these genetic units but are harder to identify and correlate.« less

Revised stratigraphy and reinterpretation of the Miocene Pohang basinfill, SE Korea: sequence development in response to tectonism and eustasy in a back-arc basin margin

NASA Astrophysics Data System (ADS)

Sohn, Y. K.; Rhee, C. W.; Shon, H.

2001-09-01

The Miocene Pohang Basin is a pull-apart basin formed along the eastern continental margin of Korea (ECMK) during the back-arc opening of the East Sea (Sea of Japan). The basin is filled by more than 1 km thick, nonmarine to deep-marine strata. These strata show extreme vertical and lateral lithofacies changes and have caused decades-long controversies on their nature and stratigraphy. Previous sedimentological studies suggest that the basinfill was deposited by a series of contemporaneously developed depositional systems, including fan delta, prodelta, slope apron, and basin plain. Detailed mapping and magnetotelluric surveying show, however, that the basinfill is composed of several packages of strata (sequences) that are bounded by distinct and laterally persistent stratigraphic discontinuities (sequence boundaries). This suggests that the depositional systems in the Pohang Basin developed sequentially rather than contemporaneously. Six packages of strata are identified in the basin: a nonmarine to shallow marine (transgressive) sequence (Sequence 1), a Gilbert-type-delta conglomerate (Sequence 2), and alternations of submarine conglomerates and hemipelagic mudstones (Sequences 3-6). The conglomerates and hemipelagic mudstones of the latter four sequences are interpreted to represent lowstand depositional systems (slope apron, submarine fan, and high-gradient delta) and condensed intervals, respectively. Compilation of geochronologic, paleomagnetic, and biostratigraphic data suggests that Sequence 1 formed during the gradual subsidence of the ECMK prior to 17 Ma, whereas Sequence 2 formed in response to abrupt downfaulting of the Pohang Basin at about 17 Ma. Both sequences are interpreted to have developed in response to the early Miocene back-arc-opening tectonism of the East Sea. On the other hand, Sequences 3-6 formed between 17 and about 10.5 Ma. The Pohang Basin was subject to only minor tectonism during this period and could record global sea-level fluctuations. We suggest that the four alternations of conglomerates (lowstand systems) and hemipelagic mudstones (condensed intervals) resulted most probably from the 3rd-order glacioeustatic cycles during the middle Miocene. This finding implies that the signatures of global sea-level fluctuations can be deciphered from a tectonically active sedimentary basin if the timing of regional tectonic development is well constrained, and the global sea-level chart of Haq et al. ( Haq, B.W., Hardenbol, J., Vail, P.R., 1987, Chronology of fluctuating sea levels since the Triassic. Science 235, 1156-1167; Haq, B.U., Hardenbol, J., Vail, P.R., 1988. Mesozoic and Cenozoic chronostratigraphy and eustatic cycles. In: Wilgus, C.K., Hastings, B.S., Posamentier, H., Van Wagoner, J., Ross, C.A., Kendall, C.G.S.C. (Eds.), Sea-Level Changes: an Integrated Approach: Soc. Econ. Paleont. Mineral. Spec. Publ. 42, pp. 71-108) may serve as a guide to basinfill interpretation even in tectonically active sedimentary basins.

Gene discovery in Boophilus microplus, the cattle tick: the transcriptomes of ovaries, salivary glands, and hemocytes.

PubMed

Santos, Isabel K F de Miranda; Valenzuela, Jesus G; Ribeiro, José Marcos C; de Castro, Marilia; Costa, Juliana Nardelli; Costa, Ana Maria; da Silva, Edson Ramiro; Neto, Olavo Bilac Rego; Rocha, Clarisse; Daffre, Sirlei; Ferreira, Beatriz R; da Silva, João Santana; Szabó, Matias Pablo; Bechara, Gervasio Henrique

2004-10-01

The quest for new control strategies for ticks can profit from high throughput genomics. In order to identify genes that are involved in oogenesis and development, in defense, and in hematophagy, the transcriptomes of ovaries, hemocytes, and salivary glands from rapidly ingurgitating females, and of salivary glands from males of Boophilus microplus were PCR amplified, and the expressed sequence tags (EST) of random clones were mass sequenced. So far, more than 1,344 EST have been generated for these tissues, with approximately 30% novelty, depending on the the tissue studied. To date approximately 760 nucleotide sequences from B. microplus are deposited in the NCBI database. Mass sequencing of partial cDNAs of parasite genes can build up this scant database and rapidly generate a large quantity of useful information about potential targets for immunobiological or chemical control.

Classical seismic sequence stratigraphic interpretation of intraslope basin fill: Deepwater Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duncan, E.A.

Detailed interpretation of seismic facies patterns performed within the workstation environment provides an observation based methodology for constructing depositional models of turbidite and other reservoir bearing systems expected in deepwater Nigeria. The increased fidelity of the workstation allows greater detail and accuracy to be imposed onto depositional model construction by vastly improving the discrimination of depositional from structural seismic reflection geometries. In deepwater Nigeria interslope basins, depositional cyclicity is clearly indicated by vertical seismic facies successions in the same way as can be recognized in bed thickness trends from outcrop or well log data. The recognition of the seismic faciesmore » successions appears to break the stratigraphy into at least fourth and fifth order scale sequences. Highly {open_quotes}zoomed{close_quotes} instantaneous phase displays enhance the reflection character so that near outcrop scale (resolution less than 50 mters) interpretations of depositional facies can be made. Common seismic facies and geologic interpretation include: (1) low angle erosional surfaces as channel scour or mass wasting detachment; (2) low relief mounds, often in compensation cycle overlapping stacks reflecting compacted channelbelt fill; (3) unidirectional, low angle clinoform sets suggesting laterial accretion within a channel belt or possible contourite mounds; (4) abrupt, shingled blocks illustrating tilted fault blocks of small scale intraformation slumping; and (5) high reflection amplitude and continuous, parallel reflections of pelagic and hemipelagic condensed sections. There are other subtle seismic facies resolvable given the incraesed fidelity of the workstation interpretation. Mapping and translation of these geometries into more robust stratigraphic predictions should have positive impact on exploration and development success.« less

Sequence and facies architecture of the upper Blackhawk Formation and the Lower Castlegate Sandstone (Upper Cretaceous), Book Cliffs, Utah, USA

NASA Astrophysics Data System (ADS)

Yoshida, S.

2000-11-01

High-frequency stratigraphic sequences that comprise the Desert Member of the Blackhawk Formation, the Lower Castlegate Sandstone, and the Buck Tongue in the Green River area of Utah display changes in sequence architecture from marine deposits to marginal marine deposits to an entirely nonmarine section. Facies and sequence architecture differ above and below the regionally extensive Castlegate sequence boundary, which separates two low-frequency (106-year cyclicity) sequences. Below this surface, high-frequency sequences are identified and interpreted as comprising the highstand systems tract of the low-frequency Blackhawk sequence. Each high-frequency sequence has a local incised valley system on top of the wave-dominated delta, and coastal plain to shallow marine deposits are preserved. Above the Castlegate sequence boundary, in contrast, a regionally extensive sheet sandstone of fluvial to estuarine origin with laterally continuous internal erosional surfaces occurs. These deposits above the Castlegate sequence boundary are interpreted as the late lowstand to early transgressive systems tracts of the low-frequency Castlegate sequence. The base-level changes that generated both the low- and high-frequency sequences are attributed to crustal response to fluctuations in compressive intraplate stress on two different time scales. The low-frequency stratigraphic sequences are attributed to changes in the long-term regional subsidence rate and regional tilting of foreland basin fill. High-frequency sequences probably reflect the response of anisotropic basement to tectonism. Sequence architecture changes rapidly across the faulted margin of the underlying Paleozoic Paradox Basin. The high-frequency sequences are deeply eroded and stack above the Paradox Basin, but display less relief and become conformable updip. These features indicate that the area above the Paradox Basin was more prone to vertical structural movements during formation of the Blackhawk-Lower Castlegate succession.

Late Pleistocene sediments and fossils near the mouth of Mad River, Humboldt County, California: Facies analysis, sequence development, and possible age correlation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, E.W.

Study of late Pleistocene-age sediments near the mouth of the Mad River revealed a sequence of nearshore marine and shallow bay deposits. This sequence, bounded by unconformities, is informally named the Mouth of Mad unit. The Mouth of mad unit can be divided into four distinct depositional facies at the study site. The lowest facies are the Nearshore Sand and Estuarine Mud, which lie unconformably on a paleosol. The sand facies grades upward into a high-energy, interbedded Nearshore Sand and Gravel facies containing storm and rip-channel deposits. Above the sand and gravel is a Strand-Plain Sand facies. This sand ismore » overlain by a laterally variable sequence of shell-rich Bay facies. The bay deposits can be further divided into five subfacies: (1) a Bioturbated Sand; (2) a Lower Tidal Flat Mud; (3) a Mixed Sand and Mud; (4) an oyster-rich Bay Mud; and (5) an Upper Tidal Flat Mud. The bay sequence is overlain unconformably by younger late Pleistocene-age marine terrace deposits. The depositional environments represented by these facies progress from a shoreline estuary to nearshore deposits, above storm wave base, and slowly back to shoreline and finally shallow bay conditions. The Mouth of Mad unit represents a transgressive-regressive sequence, involving the development of a protective spit. The uppermost mud within the Mouth of Mad unit has been dated, using thermoluminescence age estimation, at 176 [+-] 33 ka, placing it in the late Pleistocene. The Mouth of Mad unit appears to be younger than the fossiliferous deposits at Elk Head, Crannell Junction, Trinidad Head, Moonstone Beach, and the Falor Formation near Maple Creek, and possibly time equivalent with gravel deposits exposed at the western end of School Road in McKinleyville.« less

Titanium mineral resources of the western U.S.: an update

USGS Publications Warehouse

Force, Eric R.; Creely, Scott

2000-01-01

Thirteen deposits or districts in the western U.S. have been examined in which titaniummineral resources have been reported or implied. These deposits are of the following general types (in probable order of importance): 1) Cretaceous shoreline placer deposits, 2) silica-sand deposits of California, 3) fluvial monazite placers of Idaho, 4) anorthositerelated deposits, and 5) clay and bauxite deposits of the northwestern U.S. Relative to previous reports, this one shows some greater and some lesser resources (table 1). In any case, titanium-mineral resources of the western U.S. (west of 103° longitude) remain modest at world scale except as unconventional (especially perovskite) and by-product (especially porphyry) resources. Some deposits, however, have enhanced value to the titanium explorationist for the geologic relations they illustrate. Among the new conclusions are: a) Loci of Cretaceous shoreline placers form linear patterns, nested as a function of age, that can be traced for thousands of kilometers, permitting focused exploration in whole new mountain ranges. b) Medial hematite-ilmenite solid-solution, which is highly magnetic, is a major carrier of TiO2 values in the Cretaceous deposits of Wyoming. This phase was previously thought to be relatively rare. c) Regressive shoreline placer deposits in indurated Cretaceous sequences expose intricate facies relations, such as the construction of shoreface sequences by long-shore drift over tidal-channel fill, without much loss of paleogeographic information. d) Due to deep weathering, virtually every Eocene sediment that accumulated in the Ione basin at the foot of the Sierra Nevada has economic value, permitting recovery of altered ilmenite and zircon along with silica, clay, coal, and gold. Ilmenite is most abundant in newly recognized shoreline sands. e) Upper Tertiary fluvial placers of Idaho formed in and filled fault-bounded basins and thus are far more voluminous than deposits in the modern valley system. Previously reported resources are thus far too low. f) Mafic igneous rocks of Proterozoic age near Bagdad, Arizona are of ophiolitic affinity, but contain nelsonitic ilmenite enrichments associated with anorthositic layers.

MR fingerprinting using the quick echo splitting NMR imaging technique.

PubMed

Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A

2017-03-01

The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining magnetic resonance fingerprinting (MRF) technique with quick echo splitting NMR imaging technique (QUEST). A QUEST-based MRF sequence was implemented to acquire high-order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T 1 and T 2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The specific absorption rate (SAR) of MRF-QUEST was compared with the clinically available methods. MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head SAR of 0.03 W/kg. T 1 and T 2 values estimated by MRF-QUEST are in good agreement with the traditional methods. The combination of the MRF and the QUEST provides an accurate quantification of T 1 and T 2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. Magn Reson Med 77:979-988, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Microscopic and Metallurgical Aspects of the Space Shuttle Columbia Accident Investigation and Reconstruction

NASA Technical Reports Server (NTRS)

McDaniels, Steven J.

2004-01-01

The Space Shuttle Columbia was descending for a landing at the Kennedy Space Center (KSC) on February 1, 2003. Approximately 20 minutes prior to touchdown, the Columbia began disintegrating over the western United States; the majority of debris eventually impacted in eastern Texas and western Louisiana. A monumental effort eventually recovered approximately 84,000 pieces of debris, approximately 38% of the Orbiter's original dry weight. The debris was transported to KSC, where the items were catalogued and evaluated. Critical areas of interest, such as the left and right leading edge surfaces and the underside of the ship, were placed upon a grid to aid in the reconstruction. Items of interest included metallic structures, reinforced carbon-carbon composites, and ceramic heat insulation tiles. Many of the leading edge elements had re-solidified metallic deposits spattered on them. These deposits became known as slag and were one of the main focuses of the investigation. In order to help determine the sequence of events inside the left wing during the accident, the slag's composition, layering order, and directionality of deposition were studied. A myriad of analytical tests were performed in an attempt to ascertain the compositional and depositional characteristics of selected slag deposits, including the ordering of deposited layers within each individual slag deposit harvested. Initially, Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy (SEM/EDX) were performed to quickly characterize the overall composition of individual slag deposits: SEM utilizes a narrowlyfocused high-energy electron beam impinging upon a specimen. The incident beam excites and liberates lower energy secondary electrons, which are detected and analyzed, providing a visual representation of the sample's surface topography. EDX also relies on an incident electron beam, except an EDX unit measures X-ray energies generated by the impinging beam. Each element generates a unique X-ray signature; the EDX detector measures these discreet energies. EDX actually penetrates approximately 2 microns into the bulk of the sample. However, random examination of various portions of slag, coupled with the semiquantitative nature of the SEM/EDX analysis, did not yield convincingly pertinent data. Therefore, X-ray dot mapping was conducted, which provided more understandable data, both in terms of slag layering and composition. An X-ray dot map is generated by performing numerous EDX scans for individual elements, then compiling the scans in a visual representation. Eventually, specimens consisting of not only the slag, but of the adjacent RCC substrate as well were cross-sectioned. X-Ray dot mapping of the materialographicallymounted and -polished cross- sections provided a visual representation of both the layering sequence and compositional characteristics of the slag. Contemporaneously, Electron Spectroscopy for Chemical Analysis/X-Ray Photoelectron Spectroscopy (ESCA/XPS) and powdered X-Ray Diffraction (XRD) were performed to further characterize the deposits and to attempt to identify what, if any, compounds were present. The ESCA/XPS analysis allowed the analyst to "sputter" into the sample with an electron gun, aiding in the identification of the layering sequence. XPS uses photons, rather than electrons, which impinge upon the surface of the sample. XPS measures the electrons emitted from within the first 5 nm of the sample's surface. The XRD measures the scatter angles of incident X-rays; the angle and intensity of scatter depend upon the crystalline structure of the pulverized sample. XRD is considered a qualitative rather than quantitative technique. ESCA/XPS revealed that the final layer to deposit was predominantly carbonaceous. XRD was successful in identifying specific compounds, such as Al 2O3, Al and/or Al3 21SiO47, mullite (3(Al2)O3 -SiO2), and nickel-aluminides. Eventually, Electron MicroProbe Analysis (EMPA) was conducted on the marialographically-prepared cross- sections of selected slag deposits. Microprobe combines SEM and Wavelength Dispersive X-Ray Spectroscopy (WDS), and, like EDX, uses a narrowly-focused high-energy electron beam impinging upon a specimen to elicit, in the case of EPMA, characteristic X-rays with specific wavelengths. This quantitative, analytical tool proved the most useful in determining depositional layering and composition of the slag deposits. This information was utilized in verifying the location of the breach in the left leading edge of the wing of the Columbia.

Sedimentary sequence evolution in a Foredeep basin: Eastern Venezuela

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bejarano, C.; Funes, D.; Sarzalho, S.

1996-08-01

Well log-seismic sequence stratigraphy analysis in the Eastern Venezuela Foreland Basin leads to study of the evolution of sedimentary sequences onto the Cretaceous-Paleocene passive margin. This basin comprises two different foredeep sub-basins: The Guarico subbasin to the west, older, and the Maturin sub-basin to the east, younger. A foredeep switching between these two sub-basins is observed at 12.5 m.y. Seismic interpretation and well log sections across the study area show sedimentary sequences with transgressive sands and coastal onlaps to the east-southeast for the Guarico sub-basin, as well as truncations below the switching sequence (12.5 m.y.), and the Maturin sub-basin showsmore » apparent coastal onlaps to the west-northwest, as well as a marine onlap (deeper water) in the west, where it starts to establish. Sequence stratigraphy analysis of these sequences with well logs allowed the study of the evolution of stratigraphic section from Paleocene to middle Miocene (68.0-12.0 m.y.). On the basis of well log patterns, the sequences were divided in regressive-transgressive-regressive sedimentary cycles caused by changes in relative sea level. Facies distributions were analyzed and the sequences were divided into simple sequences or sub- sequences of a greater frequencies than third order depositional sequences.« less

Sedimentary processes on the Storfjorden trough-mouth fan during last deglaciation phase: the role of subglacial meltwater plumes on continental margin sedimentation

NASA Astrophysics Data System (ADS)

Lucchi, Renata G.; Camerlenghi, Angelo; Colmenero-Hidalgo, Elena; Sierro, Francisco J.; Bárcena, Maria Angeles; Flores, José-Abel; Urgeles, Roger; Macrı, Patrizia; Sagnotti, Leonardo; Caburlotto, Andrea

2010-05-01

The continental margin of the Southern Storfjorden trough-mouth fan was investigated within the SVAIS project (BIO Hesperides cruise, August 2007) as a Spanish contribution to IPY Activity N. 367 (Neogene ice streams and sedimentary processes on high- latitude continental margins - NICE STREAMS). The objectives were to investigate the glacially-dominated late-Neogene-Quaternary sedimentary architecture of the NW Barents Sea continental margin and reconstruct its sedimentary system in response to natural climate change. The paleo-ice streams in Storfjorden had a small catchment area draining ice from the southern Spitsbergen and Bear Island. The short distance from the ice source to the calving front produced a short residence time of ice, and therefore a rapid response to climatic changes. Here ground truthing recovered the last few thousands years sedimentary sequence thought to represent last deglaciation phase. Detailed palaeostratigraphic investigations together with paleomagnetic and rock magnetic analyses and AMS dating define the constraints for high-resolution inter-core correlation and dating. Most of the cores contain at the base gravity-mass deposits including debris flows and over-consolidated glacigenic diamicton. Mass deposits are overlain by an oxidized interval originated at the release and sink of fresh, cold and oxygenated melt-waters at the inception of the deglaciation phase. On the upper slope the oxidized interval is overlain by several meters of finely-stratified sediments composed of sandy-silt layers cyclically recurring within finer-grained laminated silty-clay sediments. Textural and compositional analyses suggest preferential deposition by settling from meltwater sediment-laden plumes (plumites) occurred during deglaciation with coarser layers representing episodes of subglacial meltwater discharge (glacial hyperpycnal flows) accompanying the ice streams retreat. The laminated sequence is truncated at uppermost part by a more recent gravity-mass deposit that possibly removed part of the younger sequence. In the deeper part of the slope the plumites consist of crudely laminated, terrigenous and almost barren sediments. Here the sedimentary sequence is topped by intensively bioturbated, bioclasts-bearing silty-clays representing the most recent interglacial sedimentation. On the continental shelf, the upper sedimentary sequence contains dispersed cm-thick bivalve's shells suggesting an oxygenated and nutrient-rich environment (interglacial) overlaying an interval of terrigenous, barren sediments (deglaciation). Here the short core's length suggests the presence of stiffer/coarser sediments at the base that could not be sampled. The seismic stratigraphy indicates that the slope is formed by alternating debris flow deposits and layered sediments corresponding into our cores to the fast-deposited, low-density, terrigenous plumites. Bathymetric and seismic data revealed the presence of widespread submarine landslides restricted to the southernmost part of Storfjorden continental slope. Geotechnical investigation are in progress in order to understand if such layered deposits can act on the slope as a possible preferential weak horizon favoring sediment failure.

The terminal Permian in European Russia: Vyaznikovian Horizon, Nedubrovo Member, and Permian-Triassic boundary

NASA Astrophysics Data System (ADS)

Lozovsky, V. R.; Balabanov, Yu. P.; Karasev, E. V.; Novikov, I. V.; Ponomarenko, A. G.; Yaroshenko, O. P.

2016-07-01

The comprehensive analysis of the data obtained on terrestrial vertebrata, ostracods, entomologic fauna, megaflora, and microflora in deposits of the Vyaznikovian Horizon and Nedubrovo Member, as well as the paleomagnetic data measured in enclosing rocks, confirms heterogeneity of these deposits. Accordingly, it is necessary to distinguish these two stratons in the terminal Permian of the East European Platform. The combined sequence of Triassic-Permian boundary deposits in the Moscow Syneclise, which is considered to be the most complete sequence in the East European Platform, is as follows (from bottom upward): Vyatkian deposits; Vyaznikovian Horizon, including Sokovka and Zhukovo members; Nedubrovo Member (Upper Permian); Astashikha and Ryabi members of the Vokhmian Horizon (Lower Triassic). None of the sequences of Permian-Triassic boundary deposits known in the area of study characterizes this sequence in full volume. In the north, the Triassic deposits are underlain by the Nedubrovo Member; in the south (the Klyazma River basin), the sections are underlain by the Vyaznikovian Horizon. The Permian-Triassic boundary adopted in the General Stratigraphic Scale of Russia for continental deposits of the East European platform (the lower boundary of the Astashikha Member) is more ancient than the one adopted in the International Stratigraphic Chart. The same geological situation is observed in the German Basin and other localities where Triassic continental deposits are developed. The ways of solving this problem are discussed in this article.

Sedimentology and hydrodynamic implications of a coarse-grained hurricane sequence in a carbonate reef setting

USGS Publications Warehouse

Spiske, M.; Jaffe, B.E.

2009-01-01

Storms and associated surges are major coast-shaping processes. Nevertheless, no typical sequences for storm surge deposits in different coastal settings have been established. This study interprets a coarse-grained hurricane ridge deposit on the island of Bonaire, Netherlands Antilles. The sequence was deposited during Hurricane Lenny in November 1999. Insight is gained into the hydrodynamics of surge flow by interpreting textural trends, particle imbrication, and deposit geometry. Vertical textural variations, caused by time-dependent hydrodynamic changes, were used to subdivide the deposit into depositional units that correspond to different stages of the surge, such as setup, peak, and return flow. Particle size and imbrication trends and geometry of the units reflect landward bed-load transport of components during the setup, a nondirectional flow with sediment falling out of suspension during the peak, and a seaward bedload transport during the return flow. Formation of a ridge during setup affected the texture of the return flow unit. Changing angles of imbrication reflect alternating flow velocities during each phase. Normal grading during setup and inverse grading during return flow are caused by decelerating and accelerating flow, respectively. Hence, the interpreted deposit seems to represent the first described complete hurricane surge sequence from a carbonate environment. ?? 2009 Geological Society of America.

Sedimentary evolution of the Pliocene and Pleistocene Ebro margin, northeastern Spain

USGS Publications Warehouse

Alonso, B.; Field, M.E.; Gardner, J.V.; Maldonado, A.

1990-01-01

The Pliocene and Pleistocene deposits of the Spanish Ebro margin overlie a regional unconformity and contain a major disconformity. These unconformities, named Reflector M and Reflector G, mark the bases of two seismic sequences. Except for close to the upper boundary where a few small channel deposits are recognized, the lower sequence lacks channels. The upper sequence contains nine channel-levee complexes as well as base-of-slope aprons that represent the proximal part of the Valencia turbidite system. Diverse geometries and variations in seismic units distinguish shelf, slope, base-of-slope and basin-floor facies. Four events characterize the late Miocene to Pleistocene evolution of the Ebro margin: (a) formation of a paleodrainage system and an extensive erosion-to-depositional surface during the latest Miocene (Messinian), (b) deposition of hemipelagic units during the early Pliocene, (c) development of canyons during the late Pliocene to early Pleistocene, and (d) deposition of slope wedges, channel-levee complexes, and base-of-slope aprons alternating with hemipelagic deposition during the Pleistocene. Sea-level fluctuations influenced the evolution of the sedimentary sequences of the Ebro margin, but the major control was the sediment supply from the Ebro River. ?? 1990.

Sedimentary dynamics and high-frequency sequence stratigraphy of the southwestern slope of Great Bahama Bank

NASA Astrophysics Data System (ADS)

Wunsch, Marco; Betzler, Christian; Eberli, Gregor P.; Lindhorst, Sebastian; Lüdmann, Thomas; Reijmer, John J. G.

2018-01-01

New geophysical data from the leeward slope of Great Bahama Bank show how contour currents shape the slope and induce re-sedimentation processes. Along slope segments with high current control, drift migration and current winnowing at the toe of slope form a deep moat. Here, the slope progradation is inhibited by large channel incisions and the accumulation of large mass transport complexes, triggered by current winnowing. In areas where the slope is bathed by weaker currents, the accumulation of mass transport complexes and channel incision is rather controlled by the position of the sea level. Large slope failures were triggered during the Mid-Pleistocene transition and Mid-Brunhes event, both periods characterized by changes in the cyclicity or the amplitude of sea-level fluctuations. Within the seismic stratigraphic framework of third order sequences, four sequences of higher order were identified in the succession of the upper Pleistocene. These higher order sequences also show clear differences in function of the slope exposure to contour currents. Two stochastic models emphasize the role of the contour currents and slope morphology in the facies distribution in the upper Pleistocene sequences. In areas of high current influence the interplay of erosional and depositional processes form a complex facies pattern with downslope and along strike facies alterations. In zones with lower current influence, major facies alternations occur predominately in downslope direction, and a layer-cake pattern characterizes the along strike direction. Therefore, this study highlights that contour currents are an underestimated driver for the sediment distribution and architecture of carbonate slopes.

Stratigraphy and sedimentology of the K/T boundary deposit in Haiti

NASA Technical Reports Server (NTRS)

Carey, S.; Sigurdsson, H.; Dhondt, S.; Espindola, J. M.

1993-01-01

The K/T boundary sequence is exposed in uplifted carbonate sediments of the southwest peninsula of Haiti. It is found at 15 localities within the Beloc formation, a sequence of limestone and marls interpreted as a monoclinal nappe structure thrust to the north. This tectonic deformation has affected the K/T boundary deposit to varying degrees. In some cases the less competent K/T deposit has acted as a slip plane leading to extensive shearing of the boundary layer, as well as duplication of the section. The presence of glassy tektites, shocked quartz, and an Ir anomaly directly link the deposit to a bolide impact. Stratigraphic and sedimentological features of the tripartite sequence indicate that it was formed by deposition from ballistic fallout of coarse tektites, emplacement of particle gravity flows and fine grained fallout of widely dispersed impact ejecta.

Integrated biostratigraphic and sequence stratigraphic framework for Upper Cretaceous strata of the eastern Gulf Coastal Plain, USA

USGS Publications Warehouse

Mancini, E.A.; Puckett, T.M.; Tew, B.H.

1996-01-01

Upper Cretaceous (Santonian-Maastrichtian stages) strata of the eastern US Gulf Coastal Plain represent a relatively complete section of marine to nonmarine mixed siliciclastic and carbonate sediments. This section includes three depositional sequences which display characteristic systems tracts and distinct physical defining surfaces. The marine lithofacies are rich in calcareous nannoplankton and planktonic foraminifera which can be used for biostratigraphic zonation. Integration of this zonation with the lithostratigraphy and sequence stratigraphy of these strata results in a framework that can be used for local and regional intrabasin correlation and potentially for global interbasin correlation. Only the synchronous maximum flooding surfaces of these depositional sequences, however, have chronostratigraphic significance. The sequence boundaries and initial flooding surfaces are diachronous, and their use for correlation can produce conflicting results. The availability of high resolution biostratigraphy is critical for global correlation of depositional sequences. ?? 1996 Academic Press Limited.

Leg 67: the Deep Sea Drilling Project Mid-America Trench transect off Guatemala.

USGS Publications Warehouse

von Huene, Roland E.

1980-01-01

Drilling on the Cocos plate recovered a basal chalk sequence deposited during early and mid-Miocene time, a short interval of abyssal red clay, and an upper sequence of late Miocene and younger sediment deposited within an area influenced by a terrigenous source. In the trench, a mud and sand fill less than 400,000 yr old overlies the oceanic sequence. The entire section shows no evidence of compressive deformation. In contrast, the section cored on the trench's landward slope 3 km from the trench axis is affected by tectonism. The section contains a Cretaceous to Pliocene claystone sequence capped by Pliocene to Quaternary hemipelagic slope deposits.- from Authors

Recognizing the Albian-Cenomanian (OAE1d) sequence boundary using plant carbon isotopes: Dakota Formation, Western Interior Basin, USA

USGS Publications Warehouse

Grocke, D.R.; Ludvigson, Greg A.; Witzke, B.L.; Robinson, S.A.; Joeckel, R.M.; Ufnar, David F.; Ravn, R.L.

2006-01-01

Analysis of bulk sedimentary organic matter and charcoal from an Albian-Cenomanian fluvial-estuarine succession (Dakota Formation) at Rose Creek Pit (RCP), Nebraska, reveals a negative excursion of ???3???, in late Albian strata. Overlying Cenomanian strata have ??13C values of -24???, to -23???, that are similar to pre-excursion values. The absence of an intervening positive excursion (as exists in marine records of the Albian-Cenomanian boundary) likely results from a depositional hiatus. The corresponding positive ??13C event and proposed depositional hiatus are concordant with a regionally identified sequence boundary in the Dakota Formation (D2), as well as a major regressive phase throughout the globe at the Albian-Cenomanian boundary. Data from RCP confirm suggestions that some positive carbon-isotope excursions in the geologic record are coincident with regressive sea-level phases. We estimate using isotopic correlation that the D2 sequence boundary at RCP was on the order of 0.5 m.y. in duration. Therefore, interpretations of isotopic events and associated environmental phenomena, such as oceanic anoxic events, in the shallow-marine and terrestrial record may be influenced by stratigraphic incompleteness. Further investigation of terrestrial ??13C records may be useful in recognizing and constraining sea-level changes in the geologic record. ?? 2006 Geological Society of America.

The Midway sequence: A Timiskaming-type, pull-apart basin deposit in the western Wawa subprovince, Minnesota

USGS Publications Warehouse

Jirsa, M.A.

2000-01-01

The Midway sequence is an assemblage of subaerially deposited clastic and volcanic rocks that forms a narrow wedge within Neoarchean greenstone of the western Wawa subprovince of the Superior Province. Volcanic conglomerate in the Midway sequence contains clasts of stratigraphically older greenstone, together with clasts of a distinctive hornblende-phyric trachyandesite that is not represented among the older greenstone flows. The trachyandesite forms flows and pyroclastic units that are interbedded with lenticular deposits of volcanic conglomerate in a manner interpreted to indicate approximately coeval volcanism and alluvial fan - Fluvial sedimentation within a linear, restricted, and tectonically active depocentre. The Midway sequence unconformably overlies greenstone on one side and is bounded by a regional-scale, strike-slip fault on the other. Structural analyses show that the Midway sequence was deposited after an early, precleavage folding event (D1) in greenstone, but before the regional metamorphic cleavage-forming D2 deformation. Lithologic and structural attributes are consistent with deposition in a strike-slip "pull-apart" basin. The stratigraphic and structural characteristics of the Midway sequence are generally similar to those of the Timiskaming Group and Timiskaming-type rocks in Canada, and more specifically to those of the Shebandowan Group in the Thunder Bay district. This similarity implies that the latest Archean tectonic and magmatic history of the western Wawa subprovince may have been nearly synchronous over great distances.

Eustatic and far-field tectonic control on the development of an intra-platform carbonate-shoal complex: upper tongue of the Tanglewood Member, Upper Ordovician Lexington Limestone, central Kentucky, U.S.A.

NASA Astrophysics Data System (ADS)

Koirala, Dibya Raj; Ettensohn, Frank R.; Clepper, Marta L.

2016-11-01

The Lexington or Trenton Limestone is an Upper Ordovician (Chatfieldian-Edenian; upper Sandbian-lower Katian), temperate-water unit, averaging about 60-m thick, that was deposited in relatively shallow waters across the Lexington Platform in east-central United States during the Taconian Orogeny. Lexington/Trenton shallow-water deposition ended across most of the platform in late Chatfieldian time and from that point deepened upward into the more shale-rich Clays Ferry, Point Pleasant and Kope formations due to apparent sea-level rise. In central Kentucky, however, deposition of the Lexington Limestone continued into early Edenian time and includes up to 50 m of additional coarse calcarenites and calcirudites at the top, which form the Tanglewood buildup and reflect locally regressive conditions, apparently related to local structural uplift. Consequently, in central Kentucky, the Lexington is more than 100-m thick, and Lexington deposition on the buildup continued into early Edenian time as an intra-platform shoal complex that tongues out into deeper-water units in all directions. In an attempt to understand how this shoal complex developed, we examined the last major body of coarse skeletal sands in the central Kentucky Lexington Limestone, the upper tongue of the Tanglewood Member, a 12-m-thick succession of fossiliferous calcarenite and calcirudite that occurs across an area of 5200 km2 near the center of the Lexington Platform. Although relatively homogeneous, the upper Tanglewood is divisible into five, small-scale, fining-upward, sequence-like cycles, which contain prominent, widespread deformed horizons. Facies analysis indicates that four lithofacies, which reflect distinct depositional environments, comprise the sequences across the shoal complex. Lithofacies were correlated across the shoal complex by integrating cyclicity and widespread deformed horizons in order to delineate the locations of major depositional environments. Facies analysis shows that the thickest and coarsest parts of each sequence, and the shallowest depositional environments, coincide with basement fault blocks, which are known to have experienced uplift during earlier Lexington Limestone deposition. The occurrence of thick, coarse facies on the same blocks suggests that the blocks continued to experience uplift into shallow water, where tides and waves redistributed sediments during upper Tanglewood deposition. Although eustasy apparently controlled cyclicity, Taconian far-field forces generated by orogeny in the east seem to have influenced facies distribution in each cycle through reactivation of basement fault zones as synsedimentary growth faults. The example of the upper Tanglewood Member shows that tectonic far-field forces can exert important influences on the development of carbonate depositional environments, even in distal intracratonic settings like the Lexington Platform.

Dynamics of surges generated by hydrothermal blasts during the 6 August 2012 Te Maari eruption, Mt. Tongariro, New Zealand

NASA Astrophysics Data System (ADS)

Lube, Gert; Breard, Eric C. P.; Cronin, Shane J.; Procter, Jonathan N.; Brenna, Marco; Moebis, Anja; Pardo, Natalia; Stewart, Robert B.; Jolly, Arthur; Fournier, Nicolas

2014-10-01

The 6 August 2012 Te Maari eruption produced violent and widespread "cold" Pyroclastic Density Currents (PDCs) following unroofing of the pressurized hydrothermal system. Despite an erupted volume of only ~ 5 × 105 m3, and lacking any juvenile component, the 340,000 m3 of PDCs spread over an area of 6.1 km2 and had mobilities that were on the order of volcanic blasts or blast-like PDCs. This great mobility was due to strong lateral focussing of explosion energy, producing jets with initial velocities > 100 m/s. We present a type-stratigraphy for these hydrothermal-derived low-temperature PDCs that show a tripartite deposit sequence. Each of the deposit units dominates respectively three outward-gradational sedimentary facies, reflecting transitions in the propagating PDC transport and depositional mechanisms. The largest PDCs, directed west and east of the Upper Te Maari area were generated from outer-cone breccias and tuffs that were mostly highly hydrothermally altered. Landsliding and the geometry of the hydrothermal area led to the directed jetting. Initial particle-laden jets laid sheets, grading into lobes of proximal massive sand to gravel-rich facies dominated by unit A and extending up to 1 km from the vents. As the jets were collapsing, a vertically and longitudinally stratified PDC developed within the first few hundred metres from source. Exponential thinning and coarse-tail grading-dominated fining with radial distance of massive unit A resulted from fast deposition and progressive depletion of the most concentrated flow region behind the PDC head. Markedly slower tractional sedimentation from the passing PDC body and tail deposited the highly stratified and ripple-bedded fine-coarse ash of unit B. This formed distinctive dune fields of the medial dune-bedded ash-rich facies. Upwards in depositional sequences the waning of the current can be seen, by replacement of higher-energy bedforms to progressively lower ones. Downstream progressive waning and further depletion are characterised by the development of the distal wavy to planar-bedded ash-rich facies. This is increasingly dominated by the uppermost deposition unit C of laminated fine-med ash deposited by gently turbulent, dilute phoenix clouds. These high energy PDCs, sourced from flank hydrothermal systems should be regarded as a serious threat in any multihazard assessment of a stratovolcano, even though they may not be one of the major magmatic vent sites. In addition, further detailed studies of these hydrothermal jetting events and their deposits should be pursued in order to better understand large-volume volcanic blasts, which appear to be a larger scale sibling phenomenon.

Sequence stratigraphy of the Kingak Shale (Jurassic-Lower Cretaceous), National Petroleum Reserve in Alaska

USGS Publications Warehouse

Houseknecht, D.W.; Bird, K.J.

2004-01-01

Beaufortian strata (Jurassic-Lower Cretaceous) in the National Petroleum Reserve in Alaska (NPRA) are a focus of exploration since the 1994 discovery of the nearby Alpine oil field (>400 MMBO). These strata include the Kingak Shale, a succession of depositional sequences influenced by rift opening of the Arctic Ocean Basin. Interpretation of sequence stratigraphy and depositional facies from a regional two-dimensional seismic grid and well data allows the definition of four sequence sets that each displays unique stratal geometries and thickness trends across NPRA. A Lower to Middle Jurassic sequence set includes numerous transgressive-regressive sequences that collectively built a clastic shelf in north-central NPRA. Along the south-facing, lobate shelf margin, condensed shales in transgressive systems tracts downlap and coalesce into a basinal condensed section that is likely an important hydrocarbon source rock. An Oxfordian-Kimmeridgian sequence set, deposited during pulses of uplift on the Barrow arch, includes multiple transgressive-regressive sequences that locally contain well-winnowed, shoreface sandstones at the base of transgressive systems tracts. These shoreface sandstones and overlying shales, deposited during maximum flooding, form stratigraphic traps that are the main objective of exploration in the Alpine play in NPRA. A Valanginian sequence set includes at least two transgressive-regressive sequences that display relatively distal characteristics, suggesting high relative sea level. An important exception is the presence of a basal transgressive systems tract that locally contains shoreface sandstones of reservoir quality. A Hauterivian sequence set includes two transgressive-regressive sequences that constitute a shelf-margin wedge developed as the result of tectonic uplift along the Barrow arch during rift opening of the Arctic Ocean Basin. This sequence set displays stratal geometries suggesting incision and synsedimentary collapse of the shelf margin. ?? 2004. The American Association of Petroleum Geologists. All rights reserved.

Structural evolution and petroleum productivity of the Baltic basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulmishek, G.F.

The Baltic basin is an oval depression located in the western part of the Russian craton; it occupies the eastern Baltic Sea and adjacent onshore areas. The basin contains more than 5,000 m of sedimentary rocks ranging from latest Proterozoic to Tertiary in age. These rocks consist of four tectonostratigraphic sequences deposited during major tectonic episodes of basin evolution. Principal unconformities separate the sequences. The basin is underlain by a rift probably filled with Upper Proterozoic rocks. Vendian and Lower Cambrian rocks (Baikalian sequence) form two northeast-trending depressions. The principal stage of the basin development was during deposition of amore » thick Middle Cambrian-Lower Devonian (Caledonian) sequence. This stage was terminated by the most intense deformations in the basin history. The Middle Devonian-Carboniferous (Hercynian) and Permian-Tertiary (Kimmerian-Alpine) tectonic and depositional cycles only slightly modified the basin geometry and left intact the main structural framework of underlying rocks. The petroleum productivity of the basin is related to the Caledonian tectonostratigraphic sequence that contains both source rocks and reservoirs. However, maturation of source rocks, migration of oil, and formation of fields took place mostly during deposition of the Hercynian sequence.« less

Direct deposition of silver nanoplates on quartz surface by sequence pre-treatment hydroxylation and silanisation.

PubMed

Abu Bakar, Norhayati; Mat Salleh, Muhamad; Ali Umar, Akrajas; Shapter, Joseph George

2017-01-01

Silver nanoparticles deposited on quartz substrates are widely used as SERS substrates. The nanoparticles can be deposited directly from colloidal solution by dipping technique. However, the adhesion of the particles on the quartz surface is very poor. Normally the substrate is pre-treated with hydroxylation or silanisation process. In this paper, we have demonstrated that the application of the sequence pre-treatment hydroxylation and silanisation have improved the density of silver nanoplates desposited on the quartz surface. •Sequence hydroxylation and silanisation pre-treatment assists the deposition of the nanoplate on the surface.•Various immersion times of the quartz surface into the colloidal nanoplates determined size distributions and density surface of the nanoplates on the surface.

Paleo­geographic implications of molluscan assemblages in the Upper Cretaceous (Campanian) Pigeon Point Formation, California

USGS Publications Warehouse

Elder, William P.; Saul, LouElla

1993-01-01

The Pigeon Point Formation crops out along the San Mateo County coastline in a northern and southern sequence of folded and faulted strata. Correlation of the two sequences remains somewhat equivocal, although on the basis of biostratigraphy and a reversed magnetic interval both appear to have been deposited during the early to middle Campanian. Sedimentary structures suggest that the northern sequence was deposited by turbidity currents in a continental rise setting, whereas the southern sequence primarily reflects deposition in shelf and slope environments . Right-lateral offset on the San Andreas and subsidiary faults to the east of the Pigeon Point Formation can account for 100's of km of northward transport since its deposition. However, Champion and others (1984) suggested 2500 km of northward transport from a tropical setting of about 21°N. Molluscan assemblages in the formation argue strongly for a less tropical site of deposition. Relative abundances of warm and temperate taxa and the presence or absence of key species are similar to those of the Santa Ana Mountains Cretaceous section, and are indicative of a war

Laser-Assisted Cold-Sprayed Corrosion- and Wear-Resistant Coatings: A Review

NASA Astrophysics Data System (ADS)

Olakanmi, E. O.; Doyoyo, M.

2014-06-01

Laser-assisted cold spray (LACS) process will be increasingly employed for depositing coatings because of its unique advantages: solid-state deposition of dense, homogeneous, and pore-free coatings onto a range of substrates; and high build rate at reduced operating costs without the use of expensive heating and process inert gases. Depositing coatings with excellent performance indicators via LACS demands an accurate knowledge and control of processing and materials' variables. By varying the LACS process parameters and their interactions, the functional properties of coatings can be manipulated. Moreover, thermal effect due to laser irradiation and microstructural evolution complicate the interpretation of LACS mechanical deformation mechanism which is essential for elucidating its physical phenomena. In order to provide a basis for follow-on-research that leads to the development of high-productivity LACS processing of coatings, this review focuses on the latest developments in depositing corrosion- and wear-resistant coatings with the emphasis on the composition, structure, and mechanical and functional properties. Historical developments and fundamentals of LACS are addressed in an attempt to describe the physics behind the process. Typical technological applications of LACS coatings are also identified. The investigations of all process sequences, from laser irradiation of the powder-laden gas stream and the substrate, to the impingement of thermally softened particles on the deposition site, and subsequent further processes, are described. Existing gaps in the literature relating to LACS-dependent microstructural evolution, mechanical deformation mechanisms, correlation between functional properties and process parameters, processing challenges, and industrial applications have been identified in order to provide insights for further investigations and innovation in LACS deposition of wear- and corrosion-resistant coatings.

Simulating maar-diatreme volcanic systems in bench-scale experiments

NASA Astrophysics Data System (ADS)

Andrews, R. G.; White, J. D. L.; Dürig, T.; Zimanowski, B.

2015-12-01

Maar-diatreme eruptions are incompletely understood, and explanations for the processes involved in them have been debated for decades. This study extends bench-scale analogue experiments previously conducted on maar-diatreme systems and attempts to scale the results up to both field-scale experimentation and natural volcanic systems in order to produce a reconstructive toolkit for maar volcanoes. These experimental runs produced via multiple mechanisms complex deposits that match many features seen in natural maar-diatreme deposits. The runs include deeper single blasts, series of descending discrete blasts, and series of ascending blasts. Debris-jet inception and diatreme formation are indicated by this study to involve multiple types of granular fountains within diatreme deposits produced under varying initial conditions. The individual energies of blasts in multiple-blast series are not possible to infer from the final deposits. The depositional record of blast sequences can be ascertained from the proportion of fallback sedimentation versus maar ejecta rim material, the final crater size and the degree of overturning or slumping of accessory strata. Quantitatively, deeper blasts involve a roughly equal partitioning of energy into crater excavation energy versus mass movement of juvenile material, whereas shallower blasts expend a much greater proportion of energy in crater excavation.

Silurian deltaic progradation, Tassili n'Ajjer plateau, south-eastern Algeria: Sedimentology, ichnology and sequence stratigraphy

NASA Astrophysics Data System (ADS)

Djouder, Hocine; Lüning, Sebastian; Da Silva, Anne-Christine; Abdallah, Hussein; Boulvain, Frédéric

2018-06-01

The economic potential for unconventional shale oil and gas production in the Silurian of the Berkine - Ghadames and Illizi basins (BGI) in south-eastern Algeria has been recently confirmed through exploration drilling. The aim of the present paper attempts a better understanding of the Intra-Tassilian depression within the entire Silurian of the Tassili n'Ajjer plateau. The continuous deposits of the Silurian are exposed at the southern margin of the prolific BGI basins, in the Tassili n'Ajjer plateau, offering the chance to understand the sedimentology, ichnology, and to present a detailed sequence stratigraphy framework for the region. The 410 m-thick clastic Silurian sedimentary strata are subdivided into three formations in the context of sequence stratigraphy, namely: (i) the Oued Imihrou Fm. (Llandoverian) overlain by (ii) the Atafaïtafa Fm. (late Llandoverian to Wenlockian), and (iii) the Oued Tifernine Fm. (late Wenlockian to Pridolian). These can be also distinguished across the entire investigated area and laterally traceable over kilometers. Clear cyclic stacking patterns are identified within the four studied sections showing progressively a general trend of thickening- and coarsening-upward, over a complete 2nd-order megasequence (SIL-1 MS). This transgressive-regressive succession suggests deltaic progradation, shallowing and basin infilling as evidenced by numerous diagnostic sedimentary features and trace fossils, largely from eastern-to western-Tassili plateau. Indeed, the wealth of outcrop data in the Silurian siliciclastic succession enables us to distinct thirteen facies (facies A-M), ranging from shallow-to marginal-marine facies, and in turn, grouped into six facies associations (FA1-FA6). The lowermost part of the succession, which is the most prolific sources of hydrocarbons in North Africa, consists of thick organic-rich graptolite-yielding black 'hot' shales and 'lean' shales with sparse bioturbation with small Thalassinoides belonging to the distal Cruziana ichnofacies. In contrast, the uppermost part of the Silurian deposits becomes progressively coarser and fluvial in response to the progradation of the North African Akakus deltaic system, during regional sea level fall and uplifting of the region. These progradational deposits exhibit well-preserved trace fossils with moderate to high degree of bioturbation, such as Skolithos or the so-called "Tigillites" pipe-rock, Cruziana isp., Rusophycus isp., Monocraterion isp., and Syringomorpha. The SIL-1 MS is bounded by a post-glacial latest Hirnantian unconformity on the basal (SB1), as confirmed by the moderately diverse early Silurian graptolite faunas, and by the Caledonian unconformity on the top (SB7). Each of the three formations of SIL-1 MS reveals two major 3rd-order progradational sequences, commonly delineated by discontinuity surfaces (in ascending order, SB1 to SB7), and in turn, these six sequences (i.e. Si-1 to Si-6) are subdivided into at least ten shorter-term cycles. The regional extent of each unconformity is directly linked to significant facies changes and to inflection points on the global sea level curve.

Inverse bilayer magnetoelectric thin film sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yarar, E.; Piorra, A.; Quandt, E., E-mail: eq@tf.uni-kiel.de

2016-07-11

Prior investigations on magnetoelectric (ME) thin film sensors using amorphous FeCoSiB as a magnetostrictive layer and AlN as a piezoelectric layer revealed a limit of detection (LOD) in the range of a few pT/Hz{sup 1/2} in the mechanical resonance. These sensors are comprised of a Si/SiO{sub 2}/Pt/AlN/FeCoSiB layer stack, as dictated by the temperatures required for the deposition of the layers. A low temperature deposition route of very high quality AlN allows the reversal of the deposition sequence, thus allowing the amorphous FeCoSiB to be deposited on the very smooth Si substrate. As a consequence, the LOD could be enhancedmore » by almost an order of magnitude reaching 400 fT/Hz{sup 1/2} at the mechanical resonance of the sensor. Giant ME coefficients (α{sub ME}) as high as 5 kV/cm Oe were measured. Transmission electron microscopy investigations revealed highly c-axis oriented growth of the AlN starting from the Pt-AlN interface with local epitaxy.« less

Analysis on the overpressure characterization with respect to depositional environment facies: Case Study in Miri Area, Baram Delta

NASA Astrophysics Data System (ADS)

Mhd Hanapiah, N.; Yusoff, W. I. Wan; Zakariah, M. N. A.

2017-10-01

Overpressure studies in oil and gas exploration and production are carried out in order to mitigate any losses that could happen while drilling. These concerns can be addressed by enhancing the understanding of overpressure characterization in the fields. This research emphasizes in determining the pore pressure trend in Miri area to assist pore pressure prediction for future hydrocarbon exploration and production. Generally, pore pressure trends are related to mechanisms that contribute to the overpressure generation. In the region predominant overpressure are disequilibrium compaction within the prodelta shales meanwhile in outer shelf overpressure generation controlled by fluid expansion in deltaic sequence of inner shelf area. The objective of this research is to analyze the pore pressure profile of wells for determining vertical trends of pore pressure for various depositional environment facies of Miri area. Integration of rock physics and pore pressure analysis and relating the trends to environment depositional environment facies within shale underlying sand interval. Analysis done shows that overpressure top is characterize by depositional environment facies within shale underlying sand interval.

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

Environmental and faunal change in the Jurassic Sundance Seaway, western United States: a stratigraphic palaeobiological approach

NASA Astrophysics Data System (ADS)

Danise, Silvia; Holland, Steven

2017-04-01

Understanding how regional ecosystems respond to sea level and environmental perturbations is a main challenge in palaeoecology. Here we use quantitative abundance estimates, integrated within a sequence stratigraphic and environmental framework, to reconstruct benthic community changes through the 13 myr history of the Jurassic Sundance Seaway in the western United States. Faunal censuses of macroinvertebrates were obtained from marine rocks of the Gypsum Spring, Sundance and Twin Creek formations at 44 localities in Wyoming, Montana and South Dakota. Fossils were identified to species wherever possible. Ordination of samples shows a main turnover event at the Middle-Upper Jurassic transition, which coincided with the shift from carbonate to siliciclastic depositional systems in the Seaway. This shift was probably initiated by the northward migration of the North American Plate, which moved the study area from subtropical latitudes, fostering an arid climate, into progressively more humid conditions, and possibly also by global cooling at this time. Turnover was not uniform across the onshore-offshore gradient, but was higher in offshore environments, in both carbonate and siliciclastic settings. Both the Jaccard and the Bray-Curtis similarity measures indicate that taxonomic similarity decreases from onshore to offshore in successive third-order depositional sequences, although similarity values are low for both onshore and offshore environments The higher resilience of onshore communities to third-order sea-level fluctuations and to the change from a carbonate to a siliciclastic system was driven by a few abundant eurytopic species that persisted from the opening to the closing of the Seaway and that were not restricted to single depositional environments or sequences. Lower stability in offshore facies was instead controlled by the presence of more volatile stenotopic species. Such increased onshore stability in community composition contrasts with the well-documented onshore increase in taxonomic turnover rates, and indicates the need for ecological studies to complement taxonomic studies of macroevolutionary events. This study also shows how a stratigraphic palaeobiological approach is essential for understanding the link between environmental and faunal gradients, and for understanding the long-term changes in these gradients over time that produce the local stratigraphical pattern of changes in community composition.

High resolution luminescence chronology for Xiashu Loess deposits of Southeastern China

NASA Astrophysics Data System (ADS)

Yi, Shuangwen; Li, Xusheng; Han, Zhiyong; Lu, Huayu; Liu, Jinfeng; Wu, Jiang

2018-04-01

Loess deposits in Xiashu are representative of such deposits in Southeastern China that are mainly distributed in the middle and lower reaches of the Yangtze River valley. These loess-paleosol sequences provide a key archive of past climate change in humid, subtropical regions. However, the ages of the sequences are not well constrained. In this study, the standard quartz single-aliquot regenerative (SAR) dose optically stimulated luminescence (OSL) and K-feldspar post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR290) methods are used to date two loess sequences in Nanjing region. Our results show that quartz SAR OSL and K-feldspar pIRIR290 ages are more or less indistinguishable from one another up to ∼50 ka. Beyond this age, the K-feldspar pIRIR ages increased systematically with deposition depth, agreeing well with the expected ages as far as ∼200 ka. On the basis of a fully independently-dated timescale, we are therefore able to propose, for the first time, a new age model for the Xiashu Loess deposits accumulated since the penultimate interglacial period. Using our newly obtained luminescence dating ages, we observe a marked difference between the loess accumulation rates in the two sequences, potentially forced by regional depositional processes and loess preservation.

A buried marine depositional sequence (Presumpscot FM. ) N. of the marine limit, Waterboro, Maine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morency, R.E.

Subsurface investigations conducted in Waterboro, ME (York Co.) in connection with studies of two hazardous waste sites and a municipal water supply exploration project, have demonstrated that a laterally extensive sequence of marine deposits underlies surficial sediments mapped as non-esker ice contact glacio-fluvial deposits. The marine deposits consist of a fining-downwards sequence of grey, micaceous sands (fine to medium, grading down to a silty-fine sand), which grade downward into a thick ([plus minus] 30 feet) grey silt/clay unit, which itself shows a fining-downward trend. The stratigraphy is likely correlative to the Presumpscot Formation, as described by Bloom (1963). The bottommore » of the regressive marine sequence is marked at several locations by a thin layer of sand-sized biotite mica. Lodgement till was encountered only at scattered localities (in boreholes) at each site. The bedrock surface is of considerable relief, with changes of 200--300 feet over short distances detected. The sequence appears to be the record of a rapidly transgressing sea which inundated a valley where outwash had been deposited by meltwater ahead of retreating ice. As the sea retreated, up to 70 feet of sediment was deposited in a continuous, coarsening-upwards sequence. Subsequent to the marine regression, the sediments were reworked in a subaerial (braided stream) environment. The Surficial Geologic Map of Maine shows that the inland limit of late-glacial marine submergence is located approximately 8 miles southwest of Waterboro, in Alfred, Maine. The marine limit in Alfred takes the form of a NNE trending, blunt-ended embayment. The results of this study suggest that the marine embayment once extended northward from Alfred, and is now a buried feature, possibly representing a preglacial valley, which hosted an estuary in late Wisconsonian time.« less

Characterization of geologic deposits in the vicinity of US Ecology, Amargosa Basin, southern Nevada

USGS Publications Warehouse

Taylor, Emily M.

2010-01-01

Multiple approaches have been applied to better understand the characteristics of geologic units exposed at the surface and buried at depth in the vicinity of US Ecology (USE), a low-level commercial waste site in the northern Amargosa Desert, Nevada. Techniques include surficial geologic mapping and interpretation of the subsurface using borehole data. Dated deposits at depth were used to estimate rates of sediment accumulation. The subsurface lithologies have been modeled in three dimensions. Lithologic cross sections have been created from the three-dimensional model and have been compared to resistivity data at the same location. Where deposits appear offset, a fault was suspected. Global Positioning System elevation transects were measured and trenches were excavated to locate a strand of the Carrara Fault. The presence of the fault helps to better understand the shape of the potentiometric surface. These data will be used to better understand the hydrologic parameters controlling the containment of the waste at US Ecology.Quaternary geologic units exposed at the surface, in the vicinity of US Ecology, are derived from the alluvium shed off the adjacent range front and the Amargosa River. These deposits vary from modern to early Pleistocene in age. At depth, heterogeneous sands and gravel occur. Observed in deep trenches and boreholes, the subsurface deposits are characterized as fining-upward sequence of sediment from 5- to 8-meters thick. No volcanic units or fine-grained playa deposits were described in the boreholes to a depth of 200 meters. Based on Infrared Stimulated Luminescence dated core samples, short-term rates of sediment accumulation (<70,000 years) are an average of 2.7 millimeters per year, however, long-term rates (<3,900,000 years) are orders of magnitude less. Resistivity data, when compared to lithologic cross sections, generally are consistent with lithology grain size and probable soil carbonate accumulations. Surface resistivity displays a fining-upward sequence of sediments at the surface with a soil carbonate imprint. Finally, trenching north of US Ecology successfully exposed offset Quaternary deposits on a splay of the Carrara Fault. Holocene deposits do not appear to be faulted, however, a fault zone does intersect middle and late Pleistocene aged units.

Moussa virus: a new member of the Rhabdoviridae family isolated from Culex decens mosquitoes in Côte d’Ivoire

PubMed Central

Quan, Phenix-Lan; Junglen, Sandra; Tashmukhamedova, Alla; Conlan, Sean; Hutchison, Stephen K.; Kurth, Andreas; Ellerbrok, Heinz; Egholm, Michael; Briese, Thomas; Leendertz, Fabian H.; Ian Lipkin, W

2009-01-01

Characterization of arboviruses at the interface of pristine habitats and anthropogenic landscapes is crucial to comprehensive emergent disease surveillance and forecasting efforts. In context of surveillance campaign in and around a West African rainforest, particles morphologically consistent with rhabdoviruses were identified in cell cultures infected with homogenates of trapped mosquitoes. RNA recovered from these cultures was used to derive the first complete genome sequence of a rhabdovirus isolated from Culex decens mosquitoes in Côte d’Ivoire, tentatively named Moussa virus (MOUV). MOUV shows the classical genome organization of rhabdoviruses, with five open reading frames (ORF) in a linear order. However, sequences show only limited conservation (12–33% identity at amino acid level), and ORF2 and ORF3 have no significant similarity to sequences deposited in GenBank. Phylogenetic analysis indicates a potential new species with distant relationship to Tupaia and Tibrogargan virus. PMID:19804801

Moussa virus: a new member of the Rhabdoviridae family isolated from Culex decens mosquitoes in Côte d'Ivoire.

PubMed

Quan, Phenix-Lan; Junglen, Sandra; Tashmukhamedova, Alla; Conlan, Sean; Hutchison, Stephen K; Kurth, Andreas; Ellerbrok, Heinz; Egholm, Michael; Briese, Thomas; Leendertz, Fabian H; Lipkin, W Ian

2010-01-01

Characterization of arboviruses at the interface of pristine habitats and anthropogenic landscapes is crucial to comprehensive emergent disease surveillance and forecasting efforts. In context of a surveillance campaign in and around a West African rainforest, particles morphologically consistent with rhabdoviruses were identified in cell cultures infected with homogenates of trapped mosquitoes. RNA recovered from these cultures was used to derive the first complete genome sequence of a rhabdovirus isolated from Culex decens mosquitoes in Côte d'Ivoire, tentatively named Moussa virus (MOUV). MOUV shows the classical genome organization of rhabdoviruses, with five open reading frames (ORF) in a linear order. However, sequences show only limited conservation (12-33% identity at amino acid level), and ORF2 and ORF3 have no significant similarity to sequences deposited in GenBank. Phylogenetic analysis indicates a potential new species with distant relationship to Tupaia and Tibrogargan virus.

Salt lake Laguna de Fuente de Piedra (S-Spain) as Late Quaternary palaeoenvironmental archive

NASA Astrophysics Data System (ADS)

Höbig, Nicole; Melles, Martin; Reicherter, Klaus

2014-05-01

This study deals with Late Quaternary palaeoenvironmental variability in Iberia reconstructed from terrestrial archives. In southern Iberia, endorheic basins of the Betic Cordilleras are relatively common and contain salt or fresh-water lakes due to subsurface dissolution of Triassic evaporites. Such precipitation or ground-water fed lakes (called Lagunas in Spanish) are vulnerable to changes in hydrology, climate or anthropogenic modifications. The largest Spanish salt lake, Laguna de Fuente de Piedra (Antequera region, S-Spain), has been investigated and serves as a palaeoenvironmental archive for the Late Pleistocene to Holocene time interval. Several sediment cores taken during drilling campaigns in 2012 and 2013 have revealed sedimentary sequences (up to 14 m length) along the shoreline. A multi-proxy study, including sedimentology, geochemistry and physical properties (magnetic susceptibility) has been performed on the cores. The sedimentary history is highly variable: several decimetre thick silty variegated clay deposits, laminated evaporites, and even few-centimetre thick massive gypsum crystals (i.e., selenites). XRF analysis was focussed on valuable palaeoclimatic proxies (e.g., S, Zr, Ti, and element ratios) to identify the composition and provenance of the sediments and to delineate palaeoenvironmental conditions. First age control has been realized by AMS-radiocarbon dating. The records start with approximately 2-3 m Holocene deposits and reach back to the middle of MIS 3 (GS-3). The sequences contain changes in sedimentation rates as well as colour changes, which can be summarized as brownish-beige deposits at the top and more greenish-grey deposits below as well as highly variegated lamination and selenites below ca. 6 m depth. The Younger Dryas, Bølling/Allerød, and the so-called Mystery Interval/Last Glacial Maximum have presumably been identified in the sediment cores and aligned to other climate records. In general, the cores of the Laguna de Fuente de Piedra show cyclic deposition including evaporitic sequences throughout the Holocene and Late Pleistocene, indicating higher fluxes and reworking of organic/inorganic carbon as well as other indicative proxy elements like Ti, Zr and Ca/Sr ratio during Late Pleistocene times. In order to achieve a better understanding of the palaeoenvironmental history in the study area further studies are planned which encompass biological/palaeontological indicators (e.g., pollen, diatoms) as well as another geochemical isotopic techniques on evaporitic deposits such as fluid inclusion analysis.

A colluvium - travertine sedimentary succession from the Tibetan Plateau: dating and climatic significance

NASA Astrophysics Data System (ADS)

Meyer, Michael; Wang, Zhijun; Schlütz, Frank; Hoffmann, Dirk; May, Jan-Hendrik; Aldenderfer, Mark

2014-05-01

Morphodynamics and sedimentation on the Tibetan Plateau are strongly controlled by cold-arid climate conditions and distinct freeze-thaw cycles. In such a periglacial environment mass-wasting processes are dominant on mountain slopes, causing thick successions of talus and colluvium to accumulate. While periglacial slope dynamics are ubiquitous on the plateau today, they were probably much more intense during the various cold stages of the Late Pleistocene. However, the exact nature as well as the timing and duration of such temperature controlled slope dynamics on the Tibetan plateau are not well constrained. Travertines are secondary carbonates precipitated from hydrothermal springs. On the Tibetan Plateau these types of spring deposits form along neotectonic faults, where super-saturated ground water can penetrate onto the surface, facilitating degassing and carbonate precipitation. Spring carbonate formation further requires non-permanently frozen ground and reasonable humid conditions in order to recharge the ground water aquifer. Travertines hold potential for palaeoenvironmental reconstruction, because they are dateable via U-series techniques and their geochemical, biological and petrographic signature can be used to extract high resolution palaeoenvironmental information. Due to a dense network of neotectonic faults on the Tibetan plateau, travertines are relatively common. Nevertheless, the potential of these hydrothermal spring deposits as an archive for palaeoenvironmental change on the plateau has yet to be explored. Here we present the first results obtained for an unusual, non-continuous sediment sequence encountered in southern Tibet at an altitude of 4200 m asl. near Chusang village, i.e. a ca. 200 m thick succession of periglacial colluvium alternating with travertine deposits. Preliminary data indicate that travertine deposition at the Chusang hydrothermal spring occurred periodically throughout the Late Pleistocene and extensive travertine precipitation was also responsible for preserving old colluvial sediment. We combine U-series disequilibrium dating with optically stimulated luminescence dating and radiocarbon dating to constrain the depositional history of this unique sediment sequence. Sedimentological logging and geomorphological mapping is used to understand past depositional processes and environmental constraints. Comparison to published high resolution climate records that are continuous in nature (e.g. speleothem records from adjacent catchments and regions) will allow us to link this clastic-chemical sediment sequence into the broader palaeoclimatic framework of High Asia.

Austrian phase on the northern African margin inferred from sequence stratigraphy and sedimentary records in southern Tunisia (Chotts and Djeffara areas)

NASA Astrophysics Data System (ADS)

Lazzez, Marzouk; Zouaghi, Taher; Ben Youssef, Mohamed

2008-08-01

A multidisciplinary study concerning Aptian and Albian deposits is reported from petroleum wells and the exposed section. The biostratigraphic and sedimentological analysis defined four sedimentary units. Well-logging signals' analysis allows us to refine the record resolution on Aptian series and reveals, in the Djeffara field, a transgressive system tract (TST) and a highstand system tract (HST). Exceptionally, the first sequence (S1) in the Mareth 1 well and the fifth sequence in the two wells Mareth 1 and Gourine 1 reveal the lower-stand system tract (LST). The unconformities characterized by the absence of Upper Aptian (Clansayesian) and Lower to Middle Albian deposits signed by a significant gamma-ray reduction. The Middle and Upper Albian is represented by only one deposit sequence (S6) in Mareth 1. Towards the south, in the Gourine well, two deposit sequences were identified (S6 and S7); to specify the Aptian and Albian evolution of the deposit sequences, a tentative correlation has been established between the Chotts and Djeffara areas. This correlation allows us to characterize the sedimentary unconformities related to the tectonics and eustatic events. The Chotts and the Djeffara deposition areas were developed, characterized by an irregular subsidence and separated by the Tebaga Medenine high area. The Aptian-Albian subsidence platform of southern Tunisia may be considered as a block diagram of environmental deposit with regressive and transgressive trends, showing the impact of tectonic deformations on the palaeogeographic evolution of southeastern Tunisia during the Austrian phase. This study also must be replaced within regional structural patterns that may explain both the sequential and sedimentological evolution of the area. Deformations regionally identified are integrated in the more general context of both Tethyan and Atlantic areas related to the drift of the African platform.

Paleocurrents of the Middle-Upper Jurassic strata in the Paradox Basin, Colorado, inferred from anisotropy of magnetic susceptibility (AMS)

NASA Astrophysics Data System (ADS)

Ejembi, J. I.; Ferre, E. C.; Potter-McIntyre, S. L.

2017-12-01

The Middle-Upper Jurassic sedimentary strata in the southwestern Colorado Plateau recorded pervasive eolian to fluvio-lacustrine deposition in the Paradox Basin. While paleocurrents preserved in the Entrada Sandstone, an eolian deposition in the Middle Jurassic, has been well constrained and show a northwesterly to northeasterly migration of ergs from the south onto the Colorado Plateau, there is yet no clear resolution of the paleocurrents preserved in the Wanakah Formation and Tidwell Member of the Morrison Formation, both of which are important sedimentary sequences in the paleogeographic framework of the Colorado Plateau. New U-Pb detrital zircon geochronology of sandstones from these sequences suggests that an abrupt change in provenance occurred in the early Late Jurassic, with sediments largely sourced from eroding highlands in central Colorado. We measured the anisotropy of magnetic susceptibility (AMS) of sediments in oriented sandstone samples from these three successive sequences; first, to determine the paleocurrents from the orientations of the AMS fabrics in order to delineate the source area and sediments dispersal pattern and second, to determine the depositional mechanisms of the sediments. Preliminary AMS data from two study sites show consistency and clustering of the AMS axes in all the sedimentary sequences. The orientations of the Kmin - Kint planes in the Entrada Sandstone sample point to a NNE-NNW paleocurrent directions, which is in agreement with earlier studies. The orientations of the Kmin - Kint planes in the Wanakah Formation and Tidwell Member samples show W-SW trending paleocurrent directions, corroborating our hypothesis of a shift in provenance to the eroding Ancestral Front Range Mountain, located northeast of the Paradox Basin, during the Late Jurassic. Isothermal remanence magnetization (IRM) of the samples indicate that the primary AMS carriers are detrital, syndepositional ferromagnetic minerals. Thus, we contend that AMS can be successfully deployed in constraining paleocurrents in lacustrine sedimentary strata, which lacks traditional sedimentary structures for paleocurrent analyses.

Sedimentological imprints of environmental variability at the Balkan Peninsula on the sediment sequence of Lake Ohrid (Macedonia, Albania) between the Mid Pleistocene Transition and present days: The ICDP SCOPSCO project

NASA Astrophysics Data System (ADS)

Francke, Alexander; Wagner, Bernd; Leicher, Niklas; Raphael, Gromig; Leng, Melanie; Lacey, Jack; Vogel, Hendrik; Baumgarten, Henrike; Thomas, Wonik; Zanchetta, Giovanni; Roberto, Sulpizio; Krastel, Sebastian; Lindhorst, Katja

2015-04-01

The UNESCO World Heritage site of Lake Ohrid in the Balkans is thought to be the oldest, continuously existing lake in Europe. In order to unravel the geological and evolutionary history of the lake, a deep drilling campaign was conducted in spring 2013 under the umbrella of the ICDP SCOPSCO project. At the coring site "DEEP" in central parts of the lake, more than 1,500 m of sediments were recovered down to a penetration depth of 569 m blf. This sediment sequence is assumed to be more than 1.2 Ma old and likely covers the entire lacustrine deposits of the Lake Ohrid Basin. Currently, an age model for the upper 260m of the DEEP- site sequence is available. This age model is based on chronological tie points (tephrochronology), and wiggle matching of down hole logging data and (bio-)geochemistry data (XRF, TIC, TOC) from the core sequence to the global benthic stack LR04 and local insolation patterns. The data suggests that the upper 260 m of the DEEP-site sequence corresponds to the time period between the Mid Pleistocene Transition (MPT) and present days. During this period, the sedimentological properties of the sediments show a strong dependency on environmental variability in the area. Interglacial deposits appear massive or marbled, contain up to 80 % of CaCO3 (high TIC), high amounts of organic matter (high TOC) and biogenic silica (high BSi), and low contents of clastic material. Glacial deposits are predominantly marbled and calcite is generally absent. Similarly, the amounts of organic matter and biogenic silica are low, and glacial sediments predominately consist of clastic matter. Distinct layers of siderite and uniformly distributed Fe- or Mn- oxides occur in the glacial deposits, vivianite concretions occur in both the glacial and interglacial periods. High CaCO3 contents in deposits formed during warm (interglacial) periods are also known from studies on short pilot cores from Lake Ohrid and are triggered by increased productivity in the lake, such as also indicated by enhanced contents of organic matter and biogenic silica. Thereby, CaCO3 precipitation is caused by photosynthesis induced calcite precipitation during algae blooms in spring and early summer. Negligible contents of TIC in deposits formed during glacial periods can be explained by an overall low productivity (low TOC and BSi) and, in addition, by dilution of CaCO3. Dilution of CaCO3 might be a result of more acid bottom water conditions, triggered by improved mixing conditions (less thermal stratification), oxidation of OM and CO2 release from the surface sediments. Oxygenated surface sediments and degradation of organic matter are indicated by the marbled structure of the glacial sediments implying intensive bioturbation, and by TOC/TN ratios around 4, respectively. The high amount of clastic material in deposits from cold (glacial) periods can be a result of mutual dilution with calcite, organic matter and biogenic silica, but might also indicate more intensive erosion in the catchment due to a less dense vegetation cover.

The September 14, 2015 phreatomagmatic eruption of Nakadake first crater, Aso Volcano, Japan: Eruption sequence inferred from ballistic, pyroclastic density current and fallout deposits

NASA Astrophysics Data System (ADS)

Miyabuchi, Yasuo; Iizuka, Yoshiyuki; Hara, Chihoko; Yokoo, Akihiko; Ohkura, Takahiro

2018-02-01

An explosive eruption occurred at Nakadake first crater, Aso Volcano in central Kyushu, southwestern Japan, on September 14, 2015. The sequence and causes of the eruption were reconstructed from the distribution, textures, grain-size, component and chemical characteristics of the related deposits, and video record. The eruptive deposits are divided into ballistics, pyroclastic density current and ash-fall deposits. A large number of ballistic clasts (mostly < 10 cm in diameter; maximum size 1.6 m) are scattered within about 500 m from the center of the crater. Almost half of the ballistics appear as fresh and unaltered basaltic andesite rocks interpreted to be derived from a fresh batch of magma, while the rest is weakly to highly altered clasts. A relatively thin ash derived from pyroclastic density currents covered an area of 2.3 km2 with the SE-trending main axis and two minor axes to the NE and NW. The pyroclastic density current deposit (maximum thickness < 10 cm even at the crater rim) is wholly fine grained, containing no block-sized clasts. Based on the isopach map, the mass of the pyroclastic density current deposit was estimated at ca. 5.2 × 104 tons. The ash-fall deposit is finer grained and clearly distributed to about 8 km west of the source crater. The mass of the ash-fall deposit was calculated at about 2.7 × 104 tons. Adding the mass of the pyroclastic density current deposit, the total discharged mass of the September 14, 2015 eruption was 7.9 × 104 tons. The September 14 pyroclastic density current and ash-fall deposits consist of glass shards (ca. 30%), crystals (20-30%) and lithic (40-50%) grains. Most glass shards are unaltered poorly crystallized pale brown glasses which probably resulted from quenching of juvenile magma. This suggests that the September 14, 2015 event at the Nakadake first crater was a phreatomagmatic eruption. Similar phreatomagmatic eruptions occurred at the same crater on September 6, 1979 and April 20, 1990 whose eruptive masses were one order larger than that of the September 14, 2015 eruption. These events highlight the potential hazard from phreatic or phreatomagmatic eruptions at Nakadake first crater, and provide useful information that will assist in preventing or mitigating future disasters at other similar volcanoes worldwide.

Mushroom Flora of Ulleung-gun and a Newly Recorded Bovista Species in the Republic of Korea

PubMed Central

Kim, Chang Sun; Jo, Jong Won; Kwag, Young-Nam; Sung, Gi-Ho; Lee, Sle-gee; Kim, Sang-Yong; Shin, Chang-Ho

2015-01-01

We conducted five times surveys, in June, September and October in 2012; June and September 2013, to catalog the mushroom flora in Ulleung-gun, Republic of Korea. More than 400 specimens were collected, and 317 of the specimens were successfully sequenced using the ribosomal DNA internal transcribed spacer barcode marker. We also surveyed the morphological characteristics of the sequenced specimens. The specimens were classified into 2 phyla, 7 classes, 21 orders, 59 families, 122 genera, and 221 species, and were deposited in the herbarium of Korea National Arboretum. Among the collected species, 72% were saprophytic, 25% were symbiotic, and 3% were parasitic. The most common order was Agaricales (189 specimens, 132 species), followed by Polyporales (47 specimens, 27 species), Russulales (31 specimens, 22 species), Boletales (10 specimens, 7 species), and so on. Herein, we also reported the first Bovista species in Korea, which was collected from Dokdo, the far-eastern island of Korea. PMID:26539040

Essai de corrélations séquentielles au Barrémien-Aptien dans un système plateforme-bassin-plateforme le long d'un transect Danube-Gabrovo (Bulgarie du Centre-Nord)

NASA Astrophysics Data System (ADS)

Ivanov, Marin; Peybernès, Bernard; Nikolov, Todor; Ciszak, Richard; Stoykova, Krystalina; Minkovska, Vera

1997-12-01

Along a Danube-Gabrovo cross-section, from Central Fore Balkan to Moesian Platform, the Barremian-Aptian deposits are distributed within three distinct paleogeographic domains: a central terrigenous: basin (Pleven-Polski Trămbeš) and, laterally (N: Danube, S: Gabrovo) two carbonate-dominated platforms where "Urgonian" fades can be well-developed. This pattern is induced by synsedimentary extensional tectonics already active from the end of Jurassic times. The subdivision of the various series into eight 3 d order depositional sequences and the recent discovery of ammonites allow us to propose new and more reliable correlations between the traditional lithologic formations characterizing those three domains.

Aptian-Albian sea level history from Guyots in the western Pacific

NASA Astrophysics Data System (ADS)

RöHl, Ursula; Ogg, James G.

1996-10-01

Relative sea level fluctuations are an important control on patterns of sedimentation on continental margins and provide a valuable tool for regional correlations. One of the main objectives of combined Ocean Drilling Program Legs 143 and 144 was drilling the thick carbonate caps of a suite of seamounts, called guyots, scattered over the northwestern Pacific. The array of drowned Cretaceous banks includes four carbonate banks of Aptian-Albian age. These particular carbonate banks display emergent surfaces if regional sea level falls faster than the rate of guyot subsidence, or intervals of condensed parasequences and well-cemented peritidal crypto-algal flats if the rate of sea level fall is slightly less than guyot subsidence. Rapid rises of sea level following these sequence boundaries are recorded as drowning of the emergent horizons or as pronounced deepening of facies. The cored lithologies and downhole geophysical and geochemical logs were used to identify depositional sequences and surfaces of exceptional shallowing or deepening. A combination of biostratigraphic datums, carbon and strontium isotope curves, relative magnitude of surfaces of emergence, relative thicknesses of depositional sequences, sea level events, and counts of upward shallowing cycles or parasequences were used to correlate sequences among the four sites. After compensating for thermal subsidence rates at each guyot, an identical pattern of major Aptian-Albian eustatic sea level events is evident throughout this large portion of the Pacific Ocean. There are approximately 12 Aptian and 12 Albian significant sequence boundaries, of which a third were associated with major episodes of emergence. When these events are compared with Aptian-Albian relative sea level changes observed in European shelf successions, the major sequence boundaries and transgressive surges can be easily correlated, and it appears that both regions also display the same number of minor events. Therefore we can apply the relative timing of these events from the thermal subsidence rates and parasequence counts of the Pacific banks to construct an improved scaling of the associated ammonite zones and biostratigraphic datums in the Aptian-Albian interval. An electronic supplement of this material may be obtained on adiskette or via Anonymous FTP from KOSMOS.AGU.ORG (LOGINto AGU's FTP account using ANONYMOUS as the username andGUEST as the password. Go to the right directory by typing APEND.Diskette may be ordered from American Geophysical Union, 2000Florida Ave., N.W., Washington, D.C. 20009, $15.00. Payment mustaccompany order.

GFinisher: a new strategy to refine and finish bacterial genome assemblies

NASA Astrophysics Data System (ADS)

Guizelini, Dieval; Raittz, Roberto T.; Cruz, Leonardo M.; Souza, Emanuel M.; Steffens, Maria B. R.; Pedrosa, Fabio O.

2016-10-01

Despite the development in DNA sequencing technology, improving the number and the length of reads, the process of reconstruction of complete genome sequences, the so called genome assembly, is still complex. Only 13% of the prokaryotic genome sequencing projects have been completed. Draft genome sequences deposited in public databases are fragmented in contigs and may lack the full gene complement. The aim of the present work is to identify assembly errors and improve the assembly process of bacterial genomes. The biological patterns observed in genomic sequences and the application of a priori information can allow the identification of misassembled regions, and the reorganization and improvement of the overall de novo genome assembly. GFinisher starts generating a Fuzzy GC skew graphs for each contig in an assembly and follows breaking down the contigs in critical points in order to reassemble and close them using jFGap. This has been successfully applied to dataset from 96 genome assemblies, decreasing the number of contigs by up to 86%. GFinisher can easily optimize assemblies of prokaryotic draft genomes and can be used to improve the assembly programs based on nucleotide sequence patterns in the genome. The software and source code are available at http://gfinisher.sourceforge.net/.

GFinisher: a new strategy to refine and finish bacterial genome assemblies.

PubMed

Guizelini, Dieval; Raittz, Roberto T; Cruz, Leonardo M; Souza, Emanuel M; Steffens, Maria B R; Pedrosa, Fabio O

2016-10-10

Despite the development in DNA sequencing technology, improving the number and the length of reads, the process of reconstruction of complete genome sequences, the so called genome assembly, is still complex. Only 13% of the prokaryotic genome sequencing projects have been completed. Draft genome sequences deposited in public databases are fragmented in contigs and may lack the full gene complement. The aim of the present work is to identify assembly errors and improve the assembly process of bacterial genomes. The biological patterns observed in genomic sequences and the application of a priori information can allow the identification of misassembled regions, and the reorganization and improvement of the overall de novo genome assembly. GFinisher starts generating a Fuzzy GC skew graphs for each contig in an assembly and follows breaking down the contigs in critical points in order to reassemble and close them using jFGap. This has been successfully applied to dataset from 96 genome assemblies, decreasing the number of contigs by up to 86%. GFinisher can easily optimize assemblies of prokaryotic draft genomes and can be used to improve the assembly programs based on nucleotide sequence patterns in the genome. The software and source code are available at http://gfinisher.sourceforge.net/.

A short review of paleoenvironments for Lower Beaufort (Upper Permian) Karoo sequences from southern to central Africa: A major Gondwana Lacustrine episode

NASA Astrophysics Data System (ADS)

Yemane, K.; Kelts, K.

This paper compares Karoo deposits within the Lower Beaufort (Late Permian) time interval from southern to central Africa. Facies aspects are summarized for selected sequences and depositional environments assessed in connection with the palaeogeography. The comparison shows that thickness of Lower Beaufort sequences varies greatly; sequences are over a kilometre thick at the southern tip, but decrease drastically to the north, northwest and northeast, and is commonly absent from the western part of the subcontinent. Depositional environments are continental except for small estuarine intervals from a sequence in Tanzania. The commonest lithologies comprise mudstones, siltstones, arkoses and carbonates. In spite of the dominance of fluvial facies, the records preserved by intervals of lacustrine sequences suggest that large lakes were major features of the palaeogeography, and that lacustrine environments may have been dominant deposition environments. The Lower Beaufort landscape is generally interpreted as an expansive cratonic lowland with meandering rivers and streams crossing vast floodplains, which were indented by concomitant shallow lakes of various sizes. The lakes from the Karoo tectono-sedimentary terrain were often ephemeral and closely linked with fluvial processes, but large, anoxic lakers are also documented. On the other hand, giant, freshwater lakes, covered large areas of the Zambezian tectono-sedimentary terrain and may have been locally connected. Evidence from abundant freshwater fossil assemblages, particularly from the Zambezian tectono-sedimentary terrain suggest that in spite of the generally semi-arid global climate of the Upper Permian, seasonal precipitation (monsoonal?) supplied enough moisture to sustain large perennial lakes. Because of the unique nature of the Permian cotinental configuration and palaeogeography, however, modern analogues of large systems are lacking. The general lithological and palaeontological correlability of Lower Beaufort sequences suggests a similar regional palaeoclimate, whereas the differences in distribution are taken to be a result of control of tectonic settings. From the widespread occurrences of lake deposits in the African subcontinent, over relatively long interval, we conclude that lake deposits provide more information for a better understanding of Karoo palaeogeography than previously thought, since such lacustrine sequences should hold sensitive, high resolution records for palaeoenvironmental interpretations.

Tectonostratigraphy and depositional history of the Neoproterozoic volcano-sedimentary sequences in Kid area, southeastern Sinai, Egypt: Implications for intra-arc to foreland basin in the northern Arabian-Nubian Shield

NASA Astrophysics Data System (ADS)

Khalaf, E. A.; Obeid, M. A.

2013-09-01

This paper presents a stratigraphic and sedimentary study of Neoproterozoic successions of the South Sinai, at the northernmost segment of the Arabian-Nubian Shield (ANS), including the Kid complex. This complex is composed predominantly of thick volcano-sedimentary successions representing different depositional and tectonic environments, followed by four deformational phases including folding and brittle faults (D1-D4). The whole Kid area is divisible from north to south into the lower, middle, and upper rock sequences. The higher metamorphic grade and extensive deformational styles of the lower sequence distinguishes them from the middle and upper sequences. Principal lithofacies in the lower sequence include thrust-imbricated tectonic slice of metasediments and metavolcanics, whereas the middle and upper sequences are made up of clastic sediments, intermediate-felsic lavas, volcaniclastics, and dike swarms. Two distinct Paleo- depositional environments are observed: deep-marine and alluvial fan regime. The former occurred mainly during the lower sequence, whereas the latter developed during the other two sequences. These alternations of depositional conditions in the volcano-sedimentary deposits suggest that the Kid area may have formed under a transitional climate regime fluctuating gradually from warm and dry to warm and humid conditions. Geochemical and petrographical data, in conjunction with field relationships, suggest that the investigated volcano-sedimentary rocks were built from detritus derived from a wide range of sources, ranging from Paleoproterozoic to Neoproterozoic continental crust. Deposition within the ancient Kid basin reflects a complete basin cycle from rifting and passive margin development, to intra-arc and foreland basin development and, finally, basin closure. The early phase of basin evolution is similar to various basins in the Taupo volcanics, whereas the later phases are similar to the Cordilleran-type foreland basin. The progressive change in lithofacies from marine intra-arc basin to continental molasses foreland basin and from compression to extension setting respectively, imply that the source area became peneplained, where the Kid basin became stabilized as sedimentation progressed following uplift. The scenario proposed of the study area supports the role of volcanic and tectonic events in architecting the facies and stratigraphic development.

Miocene unconformities in the Central Apennines: geodynamic significance and sedimentary basin evolution

NASA Astrophysics Data System (ADS)

Cipollari, Paola; Cosentino, Domenico

1995-12-01

This paper shows the results obtained from an integrated study (geology, biostratigraphy and geochemistry) carried out on the Miocene edimentary deposits in Central Italy in order to define the timing of the sedimentary basin evolution. This paper deals also with the causes of the unconformities recorded in these basins. In the Miocene deposits of the Latina Valley and the Ernici-Simbruini Mts. several unconformities which distinguish different stratigraphic sequences have been recognized (D 0, D 1, D 2 D 3 and D 4). For each unconformity a general description together with a geodynamical significance is provided. In particular, D 0 unconformity appears to be related to a regional tectonic event (Adria-Europe collision). As a consequence, the Adria lithosphere folded and the area underwent a regional erosive event. D 1, D 2 and D 3 unconformities have had a more local tectonic control since they represent the stratigraphic record of the migration of the Apennines thrust belt/foredeep system. D 1 and D 2 unconformities are related to the late Tortonian foredeep stage, whereas D 3 is linked to the early Messinian piggy-back stage. Moreover, the D 4 unconformity, which took place during the Messinian piggy-back stage, is strictly linked to the sea-level drop of the Messinian salinity crisis. In this paper the genesis and evolution of a late Tortonian foreland basin is also stressed (Latina Valley foredeep basin). Finally, taking into account sequence boundaries, nannofossil biostratigraphy and geochemistry isotopic data, a comparison with the curve of the 3rd order of the relative coastal onlap (Haq et al., 1988) has been attempted in order to distinguish the unconformities controlled either by tectonic or eustatic processes.

Sedimentology and sequence stratigraphy of the Lower Jurassic Kayenta Formation, Colorado Plateau, United States

NASA Astrophysics Data System (ADS)

Sanabria, Diego Ignacio

2001-07-01

Detailed outcrop analysis of the Lower Jurassic Kayenta Formation provides the basis for the formulation of a new sequence stratigraphic model for arid to semi-arid continental deposits and the generation of a comprehensive set of sedimentologic criteria for the recognition of ephemeral stream deposits. Criteria for the recognition of ephemeral deposits in the ancient record were divided into three categories according to the scale of the feature being considered. The first category takes into account sedimentary structures commonly found in the record of ephemeral stream deposits including hyperconcentrated and debris flow deposits, planar parallel bedding, sigmoidal cross-bedding, hummocky cross-bedding, climbing ripple lamination, scour-and-fill structures, convolute bedding, overturned cross-bedding, ball-and-pillow structures, pocket structures, pillars, mud curls, flaser lamination, algal lamination, termite nests, and vertebrate tracks. The second category is concerned with the mesoscale facies architecture of ephemeral stream deposits and includes waning flow successions, bedform climb, downstream accretion, terminal wadi splays, and channel-fill successions indicating catastrophic flooding. At the large-scale facies architecture level, the third category, ephemeral stream deposits are commonly arranged in depositional units characterized by a downstream decrease in grain size and scale of sedimentary structures resulting from deposition in terminal fan systems. Outcrops of the Kayenta Formation and its transition to the Navajo Sandstone along the Vermilion and Echo Cliffs of Northern Arizona indicate that wet/dry climatic cyclicity exerted a major control on regional facies architecture. Two scales of wet/dry climatic cyclicity can be recognized in northern Arizona. Three sequence sets composed of rocks accumulated under predominantly dry or wet conditions are the expression of long-term climatic cyclicity. Short-term climatic cyclicity, on the other hand, is represented by high-frequency sequences composed of eolian or ephemeral fluvial deposits overlain by perennial fluvial sediments. Increased evapotranspiration rates, depressed water tables, and accumulation of eolian or ephemeral fluvial deposits characterize the dry portion of these cycles. The wet part of the cycles is marked by an increase in precipitation and the establishment of perennial fluvial systems and lacustrine basins. This depositional model constitutes a valuable tool for correlation of similar deposits in the subsurface.

Radiocarbon Dates from Volcanic Deposits of the Chaos Crags and Cinder Cone Eruptive Sequences and Other Deposits, Lassen Volcanic National Park and Vicinity, California

USGS Publications Warehouse

Clynne, Michael A.; Christiansen, Robert L.; Trimble, Deborah A.; McGeehin, John P.

2008-01-01

This contribution reports radiocarbon ages obtained from charcoal, wood and other samples collected between 1979 and 2001 in Lassen Volcanic National Park and vicinity and a few samples from other nearby localities. Most of the samples are from the Chaos Crags and Cinder Cone eruptive sequences. Brief summaries are given of the Chaos Crags and Cinder Cone eruptive sequences.

Gene Discovery through Genomic Sequencing of Brucella abortus

PubMed Central

Sánchez, Daniel O.; Zandomeni, Ruben O.; Cravero, Silvio; Verdún, Ramiro E.; Pierrou, Ester; Faccio, Paula; Diaz, Gabriela; Lanzavecchia, Silvia; Agüero, Fernán; Frasch, Alberto C. C.; Andersson, Siv G. E.; Rossetti, Osvaldo L.; Grau, Oscar; Ugalde, Rodolfo A.

2001-01-01

Brucella abortus is the etiological agent of brucellosis, a disease that affects bovines and human. We generated DNA random sequences from the genome of B. abortus strain 2308 in order to characterize molecular targets that might be useful for developing immunological or chemotherapeutic strategies against this pathogen. The partial sequencing of 1,899 clones allowed the identification of 1,199 genomic sequence surveys (GSSs) with high homology (BLAST expect value < 10−5) to sequences deposited in the GenBank databases. Among them, 925 represent putative novel genes for the Brucella genus. Out of 925 nonredundant GSSs, 470 were classified in 15 categories based on cellular function. Seven hundred GSSs showed no significant database matches and remain available for further studies in order to identify their function. A high number of GSSs with homology to Agrobacterium tumefaciens and Rhizobium meliloti proteins were observed, thus confirming their close phylogenetic relationship. Among them, several GSSs showed high similarity with genes related to nodule nitrogen fixation, synthesis of nod factors, nodulation protein symbiotic plasmid, and nodule bacteroid differentiation. We have also identified several B. abortus homologs of virulence and pathogenesis genes from other pathogens, including a homolog to both the Shda gene from Salmonella enterica serovar Typhimurium and the AidA-1 gene from Escherichia coli. Other GSSs displayed significant homologies to genes encoding components of the type III and type IV secretion machineries, suggesting that Brucella might also have an active type III secretion machinery. PMID:11159979

Learning strategy preference of 5XFAD transgenic mice depends on the sequence of place/spatial and cued training in the water maze task.

PubMed

Cho, Woo-Hyun; Park, Jung-Cheol; Chung, ChiHye; Jeon, Won Kyung; Han, Jung-Soo

2014-10-15

Learning strategy preference was assessed in 5XFAD mice, which carry 5 familial Alzheimer's disease (AD) mutations. Mice were sequentially trained in cued and place/spatial versions of the water maze task. After training, a strategy preference test was conducted in which mice were required to choose between the spatial location where the platform had previously been during the place/spatial training, and a visible platform in a new location. 5XFAD and non-transgenic control mice showed equivalent escape performance in both training tasks. However, in the strategy preference test, 5XFAD mice preferred a cued strategy relative to control mice. When the training sequence was presented in the reverse order (i.e., place/spatial training before cued training), 5XFAD mice showed impairments in place/spatial training, but no differences in cued training or in the strategy preference test comparing to control. Analysis of regional Aβ42 deposition in brains of 5XFAD mice showed that the hippocampus, which is involved in the place/spatial learning strategy, had the highest levels of Aβ42 and the dorsal striatum, which is involved in cued learning strategy, showed a small increase in Aβ42 levels. The effect of training protocol order on performance, and regional differences in Aβ42 deposition observed in 5XFAD mice, suggest differential functional recruitment of brain structures related to learning in healthy and AD individuals. Copyright © 2014 Elsevier B.V. All rights reserved.

Oolitic sandbody depositional models and geometries, Mississippian of southwest Britain: implications for petroleum exploration in carbonate ramp settings

NASA Astrophysics Data System (ADS)

Burchette, Trevor P.; Paul Wright, V.; Faulkner, Tom J.

1990-07-01

A 1000 m thick early Mississippian carbonate supersequence, the "Carboniferous Limestone" of southwest Britain, consists of three third-order depositional sequences. These comprise parasequences in various configurations, and the whole forms a carbonate ramp stack. Within this framework five major oolitic carbonate sandbodies developed: (a) Castell Coch Limestone, (b) Stowe Oolite, (c) Brofiscin Oolite, (d) Gully Oolite, and (e) High Tor Limestone. The depositional regime was storm- and wave-dominated throughout and the major sandbodies represent a range of progradational carbonate beaches, barriers and detached subtidal shoals. Analysis of the three-dimensional shapes and distribution of these five examples shows that they evolved to produce three major carbonate sandbody geometries: (a) strings, (b) sheets, and (c) wedges. These geometries are characterised using the five field examples and offered as a template which may assist in the exploration and reservoir modelling of petroleum-rich high-energy ramp systems. Progradation, for up to 40 km, of barrier islands (Stowe Oolite) and beach-ridge plains (Gully Oolite Formation) generated strings, and "thick" sheets individually up to 10-20 m thick. "Thin" shoreface-retreat carbonate packstone/grainstone sheets up to 5 m thick (High Tor limestone) developed during transgressions as veneers across flooding surfaces. These are comparable with sheet sands developed in siliciclastic shelf depositional systems. Progradation, for up to 30 km, and vertical aggradation of shoreline-detached oolite shoals (Castell Coch limestone, Brofiscin Oolite), generated basinwards-expanding or thinning wedges up to 30 m thick. Tectonically controlled stacking of strandplain sheets produced a composite carbonate sandbody up to 80 m thick (Gully Oolite). The intrinsic (sedimentary) and extrinsic (eustacy, tectonism, climate) factors which controlled these sandbody geometries are addressed. Establishing the positions of the sandbodies accurately within depositional sequences allows them to be located within inferred seismic sequence geometries and provides one possible solution to the difficult problem of predicting carbonate facies distribution in subtle stratigraphic plays. In this ramp system, the most homogeneous sandbodies (up to 30 m grainstones), with greatest reservoir facies potential, are represented by shoal-belt wedges. Potential grainstone reservoir facies in the prograding shorelines are limited to the upper parts of individual shoreface sequences (max. 10 m grainstones). For shoreline carbonate sandbodies, the greatest reservoir and stratigraphic trapping potential exists in the earliest ramp parasequences where enveloping offshore sediments are siliciclastic mudstones. In later stages, potential seals are likely to be less reliable, low-porosity outer ramp carbonates.

Sequence stratigraphic controls on reservoir characterization and architecture: case study of the Messinian Abu Madi incised-valley fill, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Fattah, Mohamed I.; Slatt, Roger M.

2013-12-01

Understanding sequence stratigraphy architecture in the incised-valley is a crucial step to understanding the effect of relative sea level changes on reservoir characterization and architecture. This paper presents a sequence stratigraphic framework of the incised-valley strata within the late Messinian Abu Madi Formation based on seismic and borehole data. Analysis of sand-body distribution reveals that fluvial channel sandstones in the Abu Madi Formation in the Baltim Fields, offshore Nile Delta, Egypt, are not randomly distributed but are predictable in their spatial and stratigraphic position. Elucidation of the distribution of sandstones in the Abu Madi incised-valley fill within a sequence stratigraphic framework allows a better understanding of their characterization and architecture during burial. Strata of the Abu Madi Formation are interpreted to comprise two sequences, which are the most complex stratigraphically; their deposits comprise a complex incised valley fill. The lower sequence (SQ1) consists of a thick incised valley-fill of a Lowstand Systems Tract (LST1)) overlain by a Transgressive Systems Tract (TST1) and Highstand Systems Tract (HST1). The upper sequence (SQ2) contains channel-fill and is interpreted as a LST2 which has a thin sandstone channel deposits. Above this, channel-fill sandstone and related strata with tidal influence delineates the base of TST2, which is overlain by a HST2. Gas reservoirs of the Abu Madi Formation (present-day depth ˜3552 m), the Baltim Fields, Egypt, consist of fluvial lowstand systems tract (LST) sandstones deposited in an incised valley. LST sandstones have a wide range of porosity (15 to 28%) and permeability (1 to 5080mD), which reflect both depositional facies and diagenetic controls. This work demonstrates the value of constraining and evaluating the impact of sequence stratigraphic distribution on reservoir characterization and architecture in incised-valley deposits, and thus has an important impact on reservoir quality evolution in hydrocarbon exploration in such settings.

Revealing the microbial community structure of clogging materials in dewatering wells differing in physico-chemical parameters in an open-cast mining area.

PubMed

Wang, Juanjuan; Sickinger, Maren; Ciobota, Valerian; Herrmann, Martina; Rasch, Helfried; Rösch, Petra; Popp, Jürgen; Küsel, Kirsten

2014-10-15

Iron rich deposits cause clogging the pumps and pipes of dewatering wells in open-cast mines, interfering with their function; however, little is known about either the microbial community structure or their potential role in the formation of these deposits. The microbial diversity and abundance of iron-oxidizing and -reducing bacteria were compared in pipe deposit samples with different levels of encrustation from 16 wells at three lignite mining sites. The groundwater varied in pH values from slightly acidic (4.5) to neutral (7.3), Fe(II) concentrations from 0.48 to 7.55 mM, oxygen content from 1.8 to 5.8 mg L(-1), and dissolved organic carbon (DOC) from 1.43 to 12.59 mg L(-1). There were high numbers of bacterial 16S rRNA gene copies in deposits, up to 2.5 × 10(10) copies g(-1) wet weight. Pyrosequencing analysis of bacterial 16S rRNA genes revealed that Proteobacteria was the most abundant phylum (63.3% of the total reads on average), followed by Actinobacteria (10.2%) and Chloroflexi (6.4%). Gallionella-related sequences dominated the bacterial community of pipe deposits and accounted for 48% of total sequence reads. Pipe deposits with amorphous ferrihydrite and schwertmannite mostly contained Gallionella (up to 1.51 × 10(10) 16S rRNA gene copies g(-1) wet weight), while more crystalline deposits showed a higher bacterial diversity. Surprisingly, the abundance of Gallionella was not correlated with groundwater pH, oxygen, or DOC content. Sideroxydans-related 16S rRNA gene copy numbers were one order of magnitude less than Gallionella, followed by acidophilic Ferrovum-related groups. Iron reducing bacteria were detected at rather low abundance, as was expected given the low iron reduction potential, although they could be stimulated by lactate amendment. The overall high abundance of Gallionella suggests that microbes may make major contributions to pipe deposit formation irrespective of the water geochemistry. Their iron oxidation activity might initiate the formation of amorphous iron oxides, potentially providing niches for other microorganisms later after crystallization, and leading to higher bacterial diversity along with deposit accumulation in later stages of clogging. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mega-features at the Table Rock phreatomagmatic complex in Christmas Valley, Oregon; Law of original horizontality need not apply

NASA Astrophysics Data System (ADS)

Brand, B. D.; Clarke, A.

2006-12-01

The Table Rock Complex (TRC; Pliocene-Pleistocene), first documented and described by (Heiken, 1971, J. Geophy Res, 76, 5615-5626) is a large and well exposed phreatomagmatic complex in the Fort Rock- Christmas Lake Valley Basin, south-central Oregon. It is ~7 by 5 km and contains two large phreatomagmatic edifices; a large southern tuff cone with a capping lava lake (TRC1), and a large broad tuff ring in the northeast (TRC2). At least five additional, smaller tuff rings were identified along the flanks of the complex, yielding a complicated network of tuff ring-tuff cone deposits. Based on the low accidental component and evidence for a lake during this time, the cause of the explosive eruptions is interpreted to be due to interaction of magma with shallow standing water. The TRC1 consists of fining-up sequences, large erosive channel scour and fill deposits, massive tuff breccias, and abundant soft sediment deformation, which suggests deposition within a standing body of water. Subaerial TRC1 deposits are found south of the edifice, but are not exposed in the north. A significant repose period occurred between the TRC1 and TRC2 eruptions, evidenced by a wave-cut terrace and 25-50 cm of diatomitic lake sediments. TRC2 produced multiple, extremely erosive pyroclastic surges, which cut and scour the TRC1 deposits. Surge deposits consist of 50-200 m wavelength cross-beds, in some areas form large U-shaped features (10-100 m deep), and can be seen plastering up and around large obstacles from previous vents. The surge-deposits blanket all other sequences and create a hummocky topography around the edifice. This suggests that TRC2 was the last eruption in the sequence. The weight of the TRC2 sediments caused the water-saturated TRC1 sediments to plastically deform into large ball and pillow features and overturned slump blocks on the order of 20-50 m thick. The smaller flank tuff-ring eruptions likely occurred sometime between the TRC1 and TRC2 events. The inner-craters of these vents are well exposed and show features such as near-vertical plastered beds, large-scale convolute bedding, and in some places deformed and folded slump blocks up to 20-120 m thick. The features observed in both TRC deposits and in the smaller flank tuff rings (e.g., large-scale soft sediment deformation, plastered-vertical bedding, accretionary/armored lapilli) are consistent with a high water-magma ratio. The highly erosive surge beds of TRC2 represent the most energetic pulse of the eruptions.

Seismic sequence stratigraphy and platform to basin reservoir structuring of Lower Cretaceous deposits in the Sidi Aïch-Majoura region (Central Tunisia)

NASA Astrophysics Data System (ADS)

Azaïez, Hajer; Bédir, Mourad; Tanfous, Dorra; Soussi, Mohamed

2007-05-01

In central Tunisia, Lower Cretaceous deposits represent carbonate and sandstone reservoir series that correspond to proven oil fields. The main problems for hydrocarbon exploration of these levels are their basin tectonic configuration and their sequence distribution in addition to the source rock availability. The Central Atlas of Tunisia is characterized by deep seated faults directed northeast-southwest, northwest-southeast and north-south. These faults limit inherited tectonic blocks and show intruded Triassic salt domes. Lower Cretaceous series outcropping in the region along the anticline flanks present platform deposits. The seismic interpretation has followed the Exxon methodologies in the 26th A.A.P.G. Memoir. The defined Lower Cretaceous seismic units were calibrated with petroleum well data and tied to stratigraphic sequences established by outcrop studies. This allows the subsurface identification of subsiding zones and thus sequence deposit distribution. Seismic mapping of these units boundary shows a structuring from a platform to basin blocks zones and helps to understand the hydrocarbon reservoir systems-tract and horizon distribution around these domains.

Recognition of maximum flooding events in mixed siliciclastic-carbonate systems: Key to global chronostratigraphic correlation

USGS Publications Warehouse

Mancini, E.A.; Tew, B.H.

1997-01-01

The maximum flooding event within a depositional sequence is an important datum for correlation because it represents a virtually synchronous horizon. This event is typically recognized by a distinctive physical surface and/or a significant change in microfossil assemblages (relative fossil abundance peaks) in siliciclastic deposits from shoreline to continental slope environments in a passive margin setting. Recognition of maximum flooding events in mixed siliciclastic-carbonate sediments is more complicated because the entire section usually represents deposition in continental shelf environments with varying rates of biologic and carbonate productivity versus siliciclastic influx. Hence, this event cannot be consistently identified simply by relative fossil abundance peaks. Factors such as siliciclastic input, carbonate productivity, sediment accumulation rates, and paleoenvironmental conditions dramatically affect the relative abundances of microfossils. Failure to recognize these complications can lead to a sequence stratigraphic interpretation that substantially overestimates the number of depositional sequences of 1 to 10 m.y. duration.

Oligocene lacustrine tuff facies, Abu Treifeya, Cairo-Suez Road, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Motelib, Ali; Kabesh, Mona; El Manawi, Abdel Hamid; Said, Amir

2015-02-01

Field investigations in the Abu Treifeya area, Cairo-Suez District, revealed the presence of Oligocene lacustrine volcaniclastic deposits of lacustrine sequences associated with an Oligocene rift regime. The present study represents a new record of lacustrine zeolite deposits associated with saponite clay minerals contained within reworked clastic vitric tuffs. The different lithofacies associations of these clastic sequences are identified and described: volcaniclastic sedimentary facies represent episodic volcaniclastic reworking, redistribution and redeposition in a lacustrine environment and these deposits are subdivided into proximal and medial facies. Zeolite and smectite minerals are mainly found as authigenic crystals formed in vugs or crusts due to the reaction of volcanic glasses with saline-alkaline water or as alteration products of feldspars. The presence of abundant smectite (saponite) may be attributed to a warm climate, with alternating humid and dry conditions characterised by the existence of kaolinite. Reddish iron-rich paleosols record periods of non-deposition intercalated with the volcaniclastic tuff sequence.

Sequence stratigraphic interpretation of parts of Anambra Basin, Nigeria using geophysical well logs and biostratigraphic data

NASA Astrophysics Data System (ADS)

Anakwuba, E. K.; Ajaegwu, N. E.; Ejeke, C. F.; Onyekwelu, C. U.; Chinwuko, A. I.

2018-03-01

The Anambra basin constitutes the southeastern lower portion of the Benue Trough, which is a large structural depression that is divided into lower, middle and upper parts; and is one of the least studied inland sedimentary basins in Nigeria. Sequence stratigraphic interpretation had been carried out in parts of the Anambra Basin using data from three wells (Alo-1 Igbariam-1 and Ajire-1). Geophysical well logs and biostratigraphic data were integrated in order to identify key bounding surfaces, subdivide the sediment packages, correlate sand continuity and interpret the environment of deposition in the fields. Biostratigraphic interpretation, using foraminifera and plankton population and diversity, reveals five maximum flooding surfaces (MFS) in the fields. Five sequence boundaries (SB) were also identified using the well log analysis. Four 3rd order genetic sequences bounded by maximum flooding surfaces (MFS-1 to MFS-6) were identified in the areas; four complete sequences and one incomplete sequence were identified in both Alo-1 and Igbariam-1 wells while Ajire-1 has an no complete sequence. The identified system tracts delineated comprises Lowstand Systems Tracts (progradational to aggradational to retrogradational packages), Transgressive Systems Tracts (retrogradational packages) and Highstand Systems Tracts (aggradational to progradational packages) in each well. The sand continuity across the fields reveal sands S1 to S5 where S1 is present in Ajire-1 well and Igbariam-1 well but not in Alo-1 well. The sands S4 to S5 run across the three fields at different depths. The formations penetrated by the wells starting from the base are; Nkporo Formation (Campanian), Mamu Formation (Late Campanian to Early Maastrichtian), Ajali Sandstone (Maastrichtian), Nsukka Formation (Late Maastrichtian to Early Palaeocene), Imo Formation (Palaeocene) and Nanka Sand (Eocene). The environments of deposition revealed are from coastal to bathyal. The sands of lowstand system tract and highstand system tract found in Ajali, Nsukka, Nkporo and Imo (Ebenebe Sandstone) Formations show good continuity and as such good reservoir qualities while the shales of the transgressive system tracts which includes the Imo Formation, Mamu, and Nkporo Formations where most of the maximum flooding surfaces were delineated, can serve as seals to the numerous reservoir units. Combinations of the reservoir sands of the lowstand system tract and highstand system tract and the shale units of the transgressive system tract can form good stratigraphic traps for hydrocarbon and hence should be hydrocarbon exploration targets.

Ramp Creek and Harrodsburg Limestones: A shoaling-upward sequence with storm-produced features in southern Indiana, U.S.A.. Carbonate petrology seminar, Indiana University

NASA Astrophysics Data System (ADS)

1987-05-01

Most previously described examples of storm-produced stratification have been reported from siliciclastic rocks. However, such features should also be common in carbonate rocks. The Mississippian (Valmeyeran) Ramp Creek and Harrodsburg Limestones, deposited on the east margin of the Illinois Basin on top of the Borden Delta, contain storm-produced features. The dolomitic, geode-bearing Ramp Creek Limestone contains muddying-upward sequences, commonly with scoured bases overlain by grainstones, packstones, wackestones, and burrowed mudstones. These sequences are similar to hummocky sequences formed by storm waves below fair-weather wave base. The middle portion of the section including the upper Ramp Creek and lower Harrodsburg Limestones contains dolomitized mud lenses of uncertain origin. They may have formed by the baffling effect of bryozoans and/or unpreserved algae. The Harrodsburg is gradational with the Ramp Creek and consists predominantly of grainstones and packstones deposited in shallower water. Low-angle cross-stratification and truncation surfaces suggest a foreshore depositional environment for the Harrodsburg. Neither formation contains any indication of supratidal deposition as has been previously suggested. Open marine conditions during deposition of both formations are indicated by the fauna which includes crinoids, bryozoans, brachiopods, corals, ostracods, echinoids, trilobites, molluscs, fish (sharks), and trace fossils.

Laser-induced periodic surface structures on zinc oxide crystals upon two-colour femtosecond double-pulse irradiation

NASA Astrophysics Data System (ADS)

Höhm, S.; Rosenfeld, A.; Krüger, J.; Bonse, J.

2017-03-01

In order to study the temporally distributed energy deposition in the formation of laser-induced periodic surface structures (LIPSS) on single-crystalline zinc oxide (ZnO), two-colour double-fs-pulse experiments were performed. Parallel or cross-polarised double-pulse sequences at 400 and 800 nm wavelength were generated by a Mach-Zehnder interferometer, exhibiting inter-pulse delays up to a few picoseconds between the sub-ablation 50-fs-pulses. Twenty two-colour double-pulse sequences were collinearly focused by a spherical mirror to the sample surface. The resulting LIPSS periods and areas were analysed by scanning electron microscopy. The delay-dependence of these LIPSS characteristics shows a dissimilar behaviour when compared to the semiconductor silicon, the dielectric fused silica, or the metal titanium. A wavelength-dependent plasmonic mechanism is proposed to explain the delay-dependence of the LIPSS on ZnO when considering multi-photon excitation processes. Our results support the involvement of nonlinear processes for temporally overlapping pulses. These experiments extend previous two-colour studies on the indirect semiconductor silicon towards the direct wide band-gap semiconductor ZnO and further manifest the relevance of the ultrafast energy deposition for LIPSS formation.

The Miocene Sommières basin, SE France: Bioclastic carbonates in a tide-dominated depositional system

NASA Astrophysics Data System (ADS)

Reynaud, Jean-Yves; James, Noël P.

2012-12-01

The Miocene Sommières Basin in SE France is a semi-enclosed depression that was connected to the Mediterranean Sea by a flooded paleo-incised valley and then filled by a suite of sediments comprising carbonate grains coming from temperate factories that were largely deposited in tidal-dominated paleoenvironments. The strata are partitioned into two sequences that reflect repeated flooding of the incised valley system, one of several similar situations in this region of France. The carbonate grains are mostly bioclasts, namely from barnacles, bryozoans, coralline algae (encrusting, branching, and rhodoliths), echinoids, and benthic foraminifers (large and small) with ostracods, sponge spicules and planktic foraminifers prominent in muddy facies. Particles were produced by shallow water carbonate factories on hard substrates (valley walls in particular), associated with subaqueous dunes, and in deeper water basinal settings. Each depositional sequence is underlain by an eroded and bored hard surface that is progressively overlain by TST subaqueous tidal dunes or storm deposits that grade up, in one case, into HST marls (the HST of the upper sequence has been removed by erosion). The lower sequence is ebb tide dominated whereas the upper sequence is flood tide dominated. The succession is interpreted to represent a TST whose tidal currents were focused by the narrow valley and a HST that reflected flooding of the overbanks. This stratigraphic and depositional motif is comparable to that in other spatially separated Neogene paleovalleys that are filled with tide-dominated clastic carbonates in the region. Together with other recently documented similar systems, these limestones constitute an important new group of carbonate sand bodies in the carbonate depositional realm.

Statistical analyses of soil properties on a quaternary terrace sequence in the upper sava river valley, Slovenia, Yugoslavia

USGS Publications Warehouse

Vidic, N.; Pavich, M.; Lobnik, F.

1991-01-01

Alpine glaciations, climatic changes and tectonic movements have created a Quaternary sequence of gravely carbonate sediments in the upper Sava River Valley, Slovenia, Yugoslavia. The names for terraces, assigned in this model, Gu??nz, Mindel, Riss and Wu??rm in order of decreasing age, are used as morphostratigraphic terms. Soil chronosequence on the terraces was examined to evaluate which soil properties are time dependent and can be used to help constrain the ages of glaciofluvial sedimentation. Soil thickness, thickness of Bt horizons, amount and continuity of clay coatings and amount of Fe and Me concretions increase with soil age. The main source of variability consists of solutions of carbonate, leaching of basic cations and acidification of soils, which are time dependent and increase with the age of soils. The second source of variability is the content of organic matter, which is less time dependent, but varies more within soil profiles. Textural changes are significant, presented by solution of carbonate pebbles and sand, and formation is silt loam matrix, which with age becomes finer, with clay loam or clayey texture. The oldest, Gu??nz, terrace shows slight deviation from general progressive trends of changes of soil properties with time. The hypothesis of single versus multiple depositional periods of deposition was tested with one-way analysis of variance (ANOVA) on a staggered, nested hierarchical sampling design on a terrace of largest extent and greatest gravel volume, the Wu??rm terrace. The variability of soil properties is generally higher within subareas than between areas of the terrace, except for the soil thickness. Observed differences in soil thickness between the areas of the terrace could be due to multiple periods of gravel deposition, or to the initial differences of texture of the deposits. ?? 1991.

Carbonate sedimentation in an extensional active margin: Cretaceous history of the Haymana region, Pontides

NASA Astrophysics Data System (ADS)

Okay, Aral I.; Altiner, Demir

2016-10-01

The Haymana region in Central Anatolia is located in the southern part of the Pontides close to the İzmir-Ankara suture. During the Cretaceous, the region formed part of the south-facing active margin of the Eurasia. The area preserves a nearly complete record of the Cretaceous system. Shallow marine carbonates of earliest Cretaceous age are overlain by a 700-m-thick Cretaceous sequence, dominated by deep marine limestones. Three unconformity-bounded pelagic carbonate sequences of Berriasian, Albian-Cenomanian and Turonian-Santonian ages are recognized: Each depositional sequence is preceded by a period of tilting and submarine erosion during the Berriasian, early Albian and late Cenomanian, which corresponds to phases of local extension in the active continental margin. Carbonate breccias mark the base of the sequences and each carbonate sequence steps down on older units. The deep marine carbonate deposition ended in the late Santonian followed by tilting, erosion and folding during the Campanian. Deposition of thick siliciclastic turbidites started in the late Campanian and continued into the Tertiary. Unlike most forearc basins, the Haymana region was a site of deep marine carbonate deposition until the Campanian. This was because the Pontide arc was extensional and the volcanic detritus was trapped in the intra-arc basins and did not reach the forearc or the trench. The extensional nature of the arc is also shown by the opening of the Black Sea as a backarc basin in the Turonian-Santonian. The carbonate sedimentation in an active margin is characterized by synsedimentary vertical displacements, which results in submarine erosion, carbonate breccias and in the lateral discontinuity of the sequences, and differs from blanket like carbonate deposition in the passive margins.

Sequence stratigraphy of upper Paleogene to Neogene carbonates exposed from Guánica bay to Guayanilla, Southern Puerto Rico.

NASA Astrophysics Data System (ADS)

Flores Hots, V. E.; Santos, H.

2016-12-01

Detailed stratigraphic columns were measured and microfacies analysis was performed in southwestern Puerto Rico to conduct a sequence stratigraphic analysis of Paleogene to Neogene strata. Two of the best exposed outcrops include the Guánica Bay and outcrops along Highway PR-132 in Guayanilla. Three depositional sequences, separated by two major sequence boundaries were found. The lower sequence occurs within the Juana Díaz Formation and is an open shelf to reef facies indicative of a Transgressive System Tract (TST), that is overlain by a High Stand System Tract (HST) marked by reef progradation. The HST in both Guánica Bay and Guayanilla is characterized by coral-rhodolith cyclicity however sections in Guánica Bay show pervasive recrystallization due to diagenetic alteration as a result of a long periods of exposure. This first sequence is Oligocene in age. The middle sequence, exposed at the eastern section of the Guánica Bay is also part of the Juana Díaz Formation and includes a turbiditic Lowstand System Tract (LST) of slope-like deposits flow, a TST constituted by coral rubble and skeletal grainstones belonging to a shallow island slope environment; and a HST that consists of an island slope chalk facies intercalated with turbidite grainstones derived storm events at the Guayanilla location. During the deposition of the middle sequence the Guánica Bay west section was topographically higher and exposed. The upper depositional sequence is Miocene in age and is composed of a TST with the transgression starting distally in the Guánica area and transgressing northward toward the Guayanilla area. These was correlated using high resolution 87Sr/86Sr isotope concentrations of shallow marine mollusks Kuphus incrassatus in the Ponce Formation at the Guánica Bay and Guayanilla locations. Facies patterns like the ones in the studied outcrops of southwestern Puerto Rico provide an exemplary environmental model of variability of paleodepositional relief, tectonic setting, variability in depositional setting of reef Sediment acumulations, the influence of storm events and variability in rock porosity by diagenetic processes yielding valuable models that may apply to potential Oligocene - Miocene hydrocarbon reservoirs.

The recent pumice eruptions of Mt. Pelée volcano, Martinique. Part I: Depositional sequences, description of pumiceous deposits

NASA Astrophysics Data System (ADS)

Traineau, Hervé; Westercamp, Denis; Bardintzeff, Jacques-Marie; Miskovsky, Jean-Claude

1989-08-01

Mount Pelée is one of the most active volcanoes of the Lesser Antilles arc, with more than twenty eruptions over the last 5000 years. Both nuée ardente-type eruptions, which are well known, and pumice eruptions, although little known, are very common in the stratigraphic record. The four younger pumice eruptions, P4 (2440 y.B.P.), P3 (2010 y.B.P.), P2 (1670 y.B.P.) and P1 (650 y.B.P.) can be used to reconstruct the eruption sequences. The various pumiceous deposits can be described as fine lithic ash layer, Plinian fall deposits, pumice and ash flow deposits with associated ash cloud fall deposits, and pumice surge deposits. Three kinds of depositional sequences have been defined. The distinctions between them are based on the occurrence of an initial Plinian phase and the generation of intraflow pyroclastic surges. The pumice eruptions of Mt. Pelée are small in intensity and magnitude, as expressed by the dispersal of their products and by the total mass of erupted material which is estimated to be less than 1 km 3 in each case. The pumice fall deposits have dispersal characteristics of small Plinian eruptions, close to the sub-Plinian type. Nevertheless, the probability of an occurrence of a new pumice eruption at Mt. Pelée is high, and the widespread distribution of pumice deposits around the volcano suggests that such an eruption is a major volcanic risk during the present stage of activity.

Complete Genome Sequence of Leptospirillum ferrooxidans Strain C2-3, Isolated from a Fresh Volcanic Ash Deposit on the Island of Miyake, Japan

PubMed Central

Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Oshima, Kenshiro; Kim, Seok-Won; Hattori, Masahira; Kamijo, Takashi

2012-01-01

A diazotrophic, acidophilic, iron-oxidizing bacterium, Leptospirillum ferrooxidans, known to be difficult to cultivate, was isolated from a fresh volcanic ash deposit on the island of Miyake, Japan. Here, we report the complete genome sequence of a cultured strain, C2-3. PMID:22815442

Complete genome sequence of Leptospirillum ferrooxidans strain C2-3, isolated from a fresh volcanic ash deposit on the island of Miyake, Japan.

PubMed

Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Oshima, Kenshiro; Kim, Seok-Won; Hattori, Masahira; Kamijo, Takashi; Ohta, Hiroyuki

2012-08-01

A diazotrophic, acidophilic, iron-oxidizing bacterium, Leptospirillum ferrooxidans, known to be difficult to cultivate, was isolated from a fresh volcanic ash deposit on the island of Miyake, Japan. Here, we report the complete genome sequence of a cultured strain, C2-3.

The age of the Keystone thrust: laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada

USGS Publications Warehouse

Fleck, R.J.; Carr, M.D.

1990-01-01

Nonmarine sedimentary and volcaniclastic foreland-basin deposits in the Spring Mountains are cut by the Contact and Keystone thrusts. These synorogenic deposits, informally designated the Lavinia Wash sequence by Carr (1980), previously were assigned a Late Jurassic to Early Cretaceous(?) age. New 40Ar.39Ar laser-fusion and incremental-heating studies of a tuff bed in the Lavinia Wash sequence support a best estimate age of 99.0 ?? 0.4 Ma, indicating that the Lavinia Wash sequence is actually late Early Cretaceous in age and establishing a maximum age for final emplacement of the Contact and Keystone thrust plates consistent with the remainder of the Mesozoic foreland thrust belt. -from Authors

The problems and promise of DNA barcodes for species diagnosis of primate biomaterials

PubMed Central

Lorenz, Joseph G; Jackson, Whitney E; Beck, Jeanne C; Hanner, Robert

2005-01-01

The Integrated Primate Biomaterials and Information Resource (www.IPBIR.org) provides essential research reagents to the scientific community by establishing, verifying, maintaining, and distributing DNA and RNA derived from primate cell cultures. The IPBIR uses mitochondrial cytochrome c oxidase subunit I sequences to verify the identity of samples for quality control purposes in the accession, cell culture, DNA extraction processes and prior to shipping to end users. As a result, IPBIR is accumulating a database of ‘DNA barcodes’ for many species of primates. However, this quality control process is complicated by taxon specific patterns of ‘universal primer’ failure, as well as the amplification or co-amplification of nuclear pseudogenes of mitochondrial origins. To overcome these difficulties, taxon specific primers have been developed, and reverse transcriptase PCR is utilized to exclude these extraneous sequences from amplification. DNA barcoding of primates has applications to conservation and law enforcement. Depositing barcode sequences in a public database, along with primer sequences, trace files and associated quality scores, makes this species identification technique widely accessible. Reference DNA barcode sequences should be derived from, and linked to, specimens of known provenance in web-accessible collections in order to validate this system of molecular diagnostics. PMID:16214744

Geology of the Deep Creek area, Washington, and its regional significance

USGS Publications Warehouse

Yates, Robert Giertz

1976-01-01

This report, although primarily concerned with the stratigraphy and structure of a lead-zinc mining district in northern Stevens County, Washington, discusses and integrates the geology of the region about the Deep Creek area. Although the study centers in an area of about 200 square miles immediately south of the International Boundary, the regional background comes from: (1)the previously undescribed Northport quadrangle to the west, (2) published reports and reconnaissance of the Metaline quadrangle to the east, and (3) from published reports and maps of a 16 mile wide area that lies to the north adjacent to these three quadrangles in British Columbia. The report is divided into three parts: (1) descriptions of rocks and structures of the Deep Creek area, (2) descriptions of the regional setting of the Deep Creek area, and (3) an analysis and interpretation of the depositional and tectonic events that produced the geologic features exposed today. In the Deep Creek area surficial deposits of sand and gravel of glacial origin cover much of the consolidated rocks, which range in age from greenschist of the late Precambrlan to albite granite of the Eocene. Three broad divisions of depositional history are represented: (1) Precambrian, (2) lower Paleozoic and (3) upper Paleozoic; the record of the Mesozoic and Eocene is fragmentary. The lower Paleozoic division is the only fossil-controlled sequence; the age of the other two divisions were established by less direct methods. Both Precambrian and upper Paleozoic sequences are dominated by fine-grained detrital sediments, the Precambrian tending towards the alumina-rich and the upper Paleozoic tending towards the black shale facies with high silica. Neither sequence has more than trivial amounts of coarse clastics. Both include limestones, but in minor abundance. The lower Paleozoic sequence, on the other hand, represents a progressive change in deposition. The sequence began during the very late Precambrian with the deposition of clean quartz sand. This was followed by the accumulation of a comparatively thin limestone unit succeeded by a thick shale. The shale grades into a thick carbonate unit which in turn is overlain by black graptolitic slates (Ordovician). This general order of deposition holds for the Cambro-Ordovician throughout the area. Precambrian rocks indigenous to the Deep Creek area, have undergone at least six tectonic events of greatly different intensities. The first three of these events are epeirogentic, the fourth involves intense folding, the fifth, crossfolding, and the sixth, block faulting without folding. These events are dated with varying degrees of precision. The two epeirogentic events of the Precambrian, one gentle folding at the beginning of Windermere time and the other high angle faulting and volcanism in mid-Windermere time, did little to deform or metamorphose the rocks. The third event consists of uplift of northern Idaho and adjacent Montana and westward decollement thrusting of essentially unfolded lower Paleozoic rocks. The decollement faulting is inferred to explain anomalous rock distribution and cannot be accurately dated. It occurred sometime after the Devonian and before the Jurassic. A late Paleozoic age is favored.

Regional stratigraphy of the south polar layered deposits (Promethei Lingula, Mars): "Discontinuity-bounded" units in images and radargrams

NASA Astrophysics Data System (ADS)

Guallini, Luca; Rossi, Angelo Pio; Forget, François; Marinangeli, Lucia; Lauro, Sebastian Emanuel; Pettinelli, Elena; Seu, Roberto; Thomas, Nicolas

2018-07-01

The Mars South Polar Layered Deposits (SPLD) are the result of depositional and erosional events, which are marked by different stratigraphic sequences and erosional surfaces. To unambiguously define the stratigraphic units at regional scale, we mapped the SPLD on the basis of observed discontinuities (i.e., unconformities, correlative discontinuities and conformities), as commonly done in terrestrial modern stratigraphy. This methodology is defined as "Discontinuity-Bounded Units" or allostratigraphy, and is complemented by geomorphological mapping. Our study focuses on Promethei Lingula (PL) and uses both high-resolution images (CTX, HiRISE) and radargrams (SHARAD) to combine surface and sub-surface observations and obtain a 3D geological reconstruction of the SPLD. One regional discontinuity (named AUR1) was defined within the studied stratigraphic succession and is exposed in several non-contiguous outcrops around PL as well as observed at depth within the ice sheet. This is the primary contact between two major depositional sequences, showing a different texture at CTX resolution. The lower sequence is characterized mainly by a "ridge and trough" morphology (Ridge and Trough Sequence; RTS) and the upper sequence shows mainly by a "stair-stepped" morphology (Stair-Stepped Sequence; SSS). On the basis of the observations, we defined two regional "discontinuity-bounded" units in PL, respectively coinciding with RTS and SSS sequences. Our stratigraphic reconstruction provides new hints on the major scale events that shaped this region. Oscillations in Martian axial obliquity could have controlled local climate conditions in the past, affecting the PL geological record.

Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi.

PubMed

Schoch, Conrad L; Robbertse, Barbara; Robert, Vincent; Vu, Duong; Cardinali, Gianluigi; Irinyi, Laszlo; Meyer, Wieland; Nilsson, R Henrik; Hughes, Karen; Miller, Andrew N; Kirk, Paul M; Abarenkov, Kessy; Aime, M Catherine; Ariyawansa, Hiran A; Bidartondo, Martin; Boekhout, Teun; Buyck, Bart; Cai, Qing; Chen, Jie; Crespo, Ana; Crous, Pedro W; Damm, Ulrike; De Beer, Z Wilhelm; Dentinger, Bryn T M; Divakar, Pradeep K; Dueñas, Margarita; Feau, Nicolas; Fliegerova, Katerina; García, Miguel A; Ge, Zai-Wei; Griffith, Gareth W; Groenewald, Johannes Z; Groenewald, Marizeth; Grube, Martin; Gryzenhout, Marieka; Gueidan, Cécile; Guo, Liangdong; Hambleton, Sarah; Hamelin, Richard; Hansen, Karen; Hofstetter, Valérie; Hong, Seung-Beom; Houbraken, Jos; Hyde, Kevin D; Inderbitzin, Patrik; Johnston, Peter R; Karunarathna, Samantha C; Kõljalg, Urmas; Kovács, Gábor M; Kraichak, Ekaphan; Krizsan, Krisztina; Kurtzman, Cletus P; Larsson, Karl-Henrik; Leavitt, Steven; Letcher, Peter M; Liimatainen, Kare; Liu, Jian-Kui; Lodge, D Jean; Luangsa-ard, Janet Jennifer; Lumbsch, H Thorsten; Maharachchikumbura, Sajeewa S N; Manamgoda, Dimuthu; Martín, María P; Minnis, Andrew M; Moncalvo, Jean-Marc; Mulè, Giuseppina; Nakasone, Karen K; Niskanen, Tuula; Olariaga, Ibai; Papp, Tamás; Petkovits, Tamás; Pino-Bodas, Raquel; Powell, Martha J; Raja, Huzefa A; Redecker, Dirk; Sarmiento-Ramirez, J M; Seifert, Keith A; Shrestha, Bhushan; Stenroos, Soili; Stielow, Benjamin; Suh, Sung-Oui; Tanaka, Kazuaki; Tedersoo, Leho; Telleria, M Teresa; Udayanga, Dhanushka; Untereiner, Wendy A; Diéguez Uribeondo, Javier; Subbarao, Krishna V; Vágvölgyi, Csaba; Visagie, Cobus; Voigt, Kerstin; Walker, Donald M; Weir, Bevan S; Weiß, Michael; Wijayawardene, Nalin N; Wingfield, Michael J; Xu, J P; Yang, Zhu L; Zhang, Ning; Zhuang, Wen-Ying; Federhen, Scott

2014-01-01

DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi. Database URL: http://www.ncbi.nlm.nih.gov/bioproject/PRJNA177353. Published by Oxford University Press 2013. This work is written by US Government employees and is in the public domain in the US.

A palynostratigraphic approach to the SW Anatolian molasse basin: Kale-Tavas molasse and Denizli molasse

NASA Astrophysics Data System (ADS)

Akgün, Funda; Sözbilir, Hasan

The study, explains stratigraphy of the Oligo-Miocene molasse around the Denizli province (SW Anatolia), based on the palynology which is also supported by the detailed mapping and correlation of the measured sections from the coal-bearing sequences of the molasse deposits. For this purpose, two huge depressions named as the Kale-Tavas molasse and Denizli molasse basins were examined. The Kale-Tavas molasse deposits has a basal unconformity with the underlying pre-Oligocene basement and begins with the Chattian Karadere and Mortuma formations which are covered unconformably by the Aquitanian Yenidere formation. An angular unconformity between the Chattian and the Burdigalian is only observed in the middle part of the basin, around Kale. In the Tavas section, the Aquitanian and the Burdigalian are absent. The Denizli molasse is characterized by Chattian-Aquitanian sequence consisting of distinctive sedimentary facies, alluvial fan and deltaic-shallow marine deposits with carbonate patch reefs. Palynostratigraphic studies, which have given the Chattian age, have been carried out from the coal lenses of alluvial fan and delta plain deposits. In addition to the palynological determinations, coral and foraminiferal content of the carbonate patch reefs which rest conformably on the coal-bearing sequences have yielded the Chattian-Aquitanian age. Two different palynomorph associations have been determined from the molasse deposits. The first palynomorph association which is established in the samples from the Sağdere and Mortuma formations, corresponds to the Chattian age, whilst the second is of the Aquitanian age. The Late Oligocene-Early Miocene which is claimed as the time of N-S-extensional tectonics in western Turkey, is related to the depositional time of the molasse sequences in the study area. Thus, the molasse is older than the basal deposits of the Gediz and Büyük Menderes grabens.

Valley-fill sequences and onlap geometries, Lower Cretaceous Muddy Sandstone, Kitty Field, Powder River basin, Wyoming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, M.H.; Gustason, E.R.

1987-05-01

The Muddy Sandstone at Kitty field is a valley-fill sequence that records a late Albian sea level rise and accompanying transgression. The valley was cut during a preceding sea level lowstand. Stratal geometries and facies successions within the valley fill demonstrate the history of transgression was not gradual and progressive. Rather, the valley fill comprises a series of discrete, time-bounded, depositional units which onlap the erosional surface. Five time-bounded depositional units were defined by facies successions and were used to define onlap geometries. Facies successions within individual units record progressive shoaling. Capping each succession, there may be a planar disconformity,more » a thin bioturbated interval, or the deepest water facies of the next depositional event. Thus, the termination of each depositional event is marked by an episode of rapid deepening. At a single geographic location, stratal successions within older depositional units represent more landward facies than those within younger units. Therefore, the onlap geometry of the valley-fill sequence consists of a landward-stepping arrangement of depositional units. The primary reservoirs within the valley-fill sequence, at Kitty field, are laterally coalesced, channel-belt sandstones at the base and barrier island sandstones at the top. Reservoir sandstones of lesser quality occur within the intermediate estuarine facies. The stacking pattern, developed by onlap of the units, results in multiple pay zones within mid-valley reaches. The boundaries of each depositional unit define a high-resolution, chronostratigraphic correlation of valley-fill strata, a correlation corroborated by bentonites. This correlation method gives an accurate description of the internal geometry of valley-fill strata and, therefore, provides a basis for understanding the process of transgressive onlap.« less

The story of landscape evolution in Lower Austria told by sedimentological analysis and luminescence dating

NASA Astrophysics Data System (ADS)

Hofer, Ingo; Thiel, Christine; Terhorst, Birgit; Jaburova, Iva; Buylaert, Jan-Pieter; Murray, Andrew; Frechen, Manfred

2010-05-01

Loess/palaeosol sequences contain detailed information about palaeoenvironmental changes during the Quaternary. Furthermore, because of its long distance aeolian transport, which resets the luminescence signal to zero prior to deposition, loess is highly suitable for luminescence dating. This allows the determination of geodynamic processes with time. The loess deposits in the Kremser Feld (Lower Austria) are up to 30 m thick. The loess/paleosol sequence of Stratzing is situated at the eastern margin of the west-east elongated hill of the ‘Galgenberg'; this location is famous for its archaeological finds, e.g. the sculpture "Fanny", one of the oldest identifiable representations of the human figure (Neugebauer-Maresch, 1993). The loess profile examined here has a total depth of 7.5 m and is subdivided into 19 prominent horizons. For each horizon the grain size distribution, pH-value, total carbonate content, total organic content and sulphur content was derived in order to reconstruct the environmental conditions leading to sedimentation and soil formation. To set up a geochronological framework for the loess deposition and the subsequent soil formation, nine samples were dated by means of elevated temperature post-IR IRSL (Thiel et al., submitted). Besides a general discussion about the sedimentological data we will discuss horizon 18 in more detail; this is a paleosol rich in clay and poor in mineralic carbonate. The sulphur content is relatively high and indicates higher humidity and warmer climate, all making the unexpectedly low organic carbon content of particular interest. The luminescence ages reveal an important hiatus above this well-developed palaeosol (from ~ 100 to ~ at least 200 ka) clearly showing that this loess/palaeosol sequence is not a continuous record. This implies either significant erosion or lack of loess deposition in this area. Neugebauer-Maresch, C., 1993. Kunst und geistige Welt. - In: Neugebauer-Maresch, C., (ed): Altsteinzeit im Osten Österreichs. Wissenschaftliche Schriftenreihe Niederösterreich 95/96/97 (St. Pölten). Thiel, C., Buylaert, J. P., Terhorst, B., Murray, A. S., Hofer, I., Tsukamoto, S., Frechen, M., submitted. Luminescence dating of the Stratzing loess profile (Austria) - Testing the potential of an elevated temperature post-IR IRSL protocol. Quaternary International.

Tectonics and metallogenesis of Proterozoic rocks of the Reading Prong

USGS Publications Warehouse

Gundersen, L.C.S.

2004-01-01

Detailed geologic mapping, petrography, and major and trace-element analyses of Proterozoic rocks from the Greenwood Lake Quadrangle, New York are compared with chemical analyses and stratigraphic information compiled for the entire Reading Prong. A persistent regional stratigraphy is evident in the mapped area whose geochemistry indicates protoliths consistent with a back-arc marginal basin sequence. The proposed marginal basin may have been floored by an older sialic basement and overlain by a basin-fill sequence consisting of a basal tholeiitic basalt, basic to intermediate volcanic or volcaniclastic rocks and carbonate sediments, a bimodal calc-alkaline volcanic sequence, and finally volcaniclastic, marine, and continental sediments. The presence of high-chlorine biotite and scapolite may indicate circulation of brine fluids or the presence of evaporite layers in the sequence. Abundant, stratabound magnetite deposits with a geologic setting very unlike that of cratonic, Proterozoic banded-iron formations are found throughout the proposed basin sequence. Associated with many of the magnetite deposits is unusual uranium and rare-earth element mineralization. It is proposed here that these deposits formed in an exhalative, volcanogenic, depositional environment within an extensional back-arc marginal basin. Such a tectonic setting is consistent with interpretations of protoliths in other portions of the Reading Prong, the Central Metasedimentary Belt of the Canadian Grenville Province, and recent interpretation of the origin of the Franklin lead-zinc deposits, suggesting a more cohesive evolving arc/back-arc tectonic model for the entire Proterozoic margin of the north-eastern portion of the North American craton. Published by Elsevier Ltd.

Depositional environments, sequence stratigraphy, and trap configuration of lower Wolfcampian clastics along eastern edge of Midland basin, west Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, N.R.; Reuter, S.G.

1989-03-01

The Lower Permian (lower Wolfcampian) along the eastern edge of the Midland basin, west Texas, is characterized by ramp-type shelf margins. During eustatic lowstand, nearshore sedimentation shifted drastically to the west into a basinal setting below the Pennsylvanian (Canyon) shelf margin. Core descriptions demonstrate that lowstand systems tract (LST) and transgressive systems tract (TST) siliciclastics were deposited in deltaic and coastal-plain environments. Prodelta, delta-front, and stream-mouth bar facies are associated with the LST. Coastal-plain and distributary channels are preserved in the TST. The sequence stratigraphic framework indicates type 1 sequence boundaries at 287 Ma, 282 Ma, and 280 Ma inmore » the lower Wolfcampian clastics. This lower Wolfcampian package of sedimentary rocks overlies the Pennsylvanian and is capped by the 279-Ma middle Wolfcampian unconformity. All three sequence boundaries and associated systems tract deposits exhibit a prograding stacking pattern within the sequence stratigraphic framework. Basinally restricted prograding LST deltaic rocks are overlain by backstepping TST deltaics and highstand systems tract (HST) outer marine shales. Production in lower Wolfcampian clastic fields is associated with fine-grained quartzarenites up to 45 ft thick which were deposited in stream-mouth bars. Delta-front and prodelta low-permeability shales encase the reservoir facies, forming lateral permeability barriers. HST outer marine shales deposited over the stream-mouth-bar sandstones act as a top seal, creating a stratigraphic trap and providing source for the high-BTU gas and oil produced from these basinally restricted LST deltaics.« less

Upper Lower Cambrian depositional sequence in Avalonian New Brunswick

USGS Publications Warehouse

Landing, E.; Westrop, S.R.

1996-01-01

The Hanford Brook Formation (emended) is a thin (up to 42+ m), upper Lower Cambrian depositional sequence that is unconformably bounded by the lower Lower Cambrian (Random Formation) and the middle Middle Cambrian (Fossil Brook Member of the Chamberlain's Brook Formation). These stratigraphic relationships of the trilobite-bearing Hanford Brook Formation indicate deposition on the Avalonian marginal platform in the Saint John, New Brunswick, region and provide more evidence for a uniform, latest Precambrian-Cambrian epeirogenic history and cover sequence in Avalon. The Hanford Brook Formation is a deepening - shoaling sequence with (i) lower, transgressive sandstone deposited in episodically high-energy environments (St. Martins Member, new); (ii) highstand-regressive, dysaerobic mudstone - fine-grained sandstone with volcanic ashes (Somerset Street Member, new); and (iii) upper, regressive, planar and hummocky cross-stratified sandstone (Long Island Member, new). Trilobites are common in the distal Somerset Street Member, and ostracodes and brachiopods dominate the St. Martins and Long Island members. Condensation of the St. Martins Member and absence of the Long Island Member where the Random Formation and Fossil Brook Member are thinnest suggest onlap of the Hanford Brook and pronounced, sub-Middle Cambrian erosion across epeirogenically active blocks in southern New Brunswick.

Biodiversity hot spot on a hot spot: novel extremophile diversity in Hawaiian fumaroles.

PubMed

Wall, Kate; Cornell, Jennifer; Bizzoco, Richard W; Kelley, Scott T

2015-01-06

Fumaroles (steam vents) are the most common, yet least understood, microbial habitat in terrestrial geothermal settings. Long believed too extreme for life, recent advances in sample collection and DNA extraction methods have found that fumarole deposits and subsurface waters harbor a considerable diversity of viable microbes. In this study, we applied culture-independent molecular methods to explore fumarole deposit microbial assemblages in 15 different fumaroles in four geographic locations on the Big Island of Hawai'i. Just over half of the vents yielded sufficient high-quality DNA for the construction of 16S ribosomal RNA gene sequence clone libraries. The bacterial clone libraries contained sequences belonging to 11 recognized bacterial divisions and seven other division-level phylogenetic groups. Archaeal sequences were less numerous, but similarly diverse. The taxonomic composition among fumarole deposits was highly heterogeneous. Phylogenetic analysis found cloned fumarole sequences were related to microbes identified from a broad array of globally distributed ecotypes, including hot springs, terrestrial soils, and industrial waste sites. Our results suggest that fumarole deposits function as an "extremophile collector" and may be a hot spot of novel extremophile biodiversity. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Biodiversity hot spot on a hot spot: novel extremophile diversity in Hawaiian fumaroles

PubMed Central

Wall, Kate; Cornell, Jennifer; Bizzoco, Richard W; Kelley, Scott T

2015-01-01

Fumaroles (steam vents) are the most common, yet least understood, microbial habitat in terrestrial geothermal settings. Long believed too extreme for life, recent advances in sample collection and DNA extraction methods have found that fumarole deposits and subsurface waters harbor a considerable diversity of viable microbes. In this study, we applied culture-independent molecular methods to explore fumarole deposit microbial assemblages in 15 different fumaroles in four geographic locations on the Big Island of Hawai'i. Just over half of the vents yielded sufficient high-quality DNA for the construction of 16S ribosomal RNA gene sequence clone libraries. The bacterial clone libraries contained sequences belonging to 11 recognized bacterial divisions and seven other division-level phylogenetic groups. Archaeal sequences were less numerous, but similarly diverse. The taxonomic composition among fumarole deposits was highly heterogeneous. Phylogenetic analysis found cloned fumarole sequences were related to microbes identified from a broad array of globally distributed ecotypes, including hot springs, terrestrial soils, and industrial waste sites. Our results suggest that fumarole deposits function as an “extremophile collector” and may be a hot spot of novel extremophile biodiversity. PMID:25565172

Magnetic susceptibility variations in Loess sequences and their relationship to astronomical forcing

NASA Technical Reports Server (NTRS)

Verosub, Kenneth L.; Singer, Michael J.

1992-01-01

The long, well-exposed and often continuous sequences of loess found throughout the world are generally thought to provide an excellent opportunity for studying long-term, large-scale environmental change during the last few million years. In recent years, the most fruitful loess studies have been those involving the deposits of the loess in China. One of the most intriguing results of that work has been the discovery of an apparent correlation between variations in the magnetic susceptibility of the loess sequence and the oxygen isotope record of the deep sea. This correlation implies that magnetic susceptibility variations are being driven by astronomical parameters. However, the basic data have been interpreted in various ways by different authors, most of whom assumed that the magnetic minerals in the loess have not been affected by post-depositional processes. Using a chemical extraction procedure that allows us to separate the contribution of secondary pedogenic magnetic minerals from primary inherited magnetic minerals, we have found that the magnetic susceptibility of the Chinese paleosols is largely due to a pedogenic component which is present to a lesser degree in the loess. We have also found that the smaller inherited component of the magnetic susceptibility is about the same in the paleosols and the loess. These results demonstrate the need for additional study of the processes that create magnetic susceptibility variations in order to interpret properly the role of astronomical forcing in producing these variations.

Erosion and deposition on a debris-flow fan

NASA Astrophysics Data System (ADS)

Densmore, A. L.; Schuerch, P.; Rosser, N. J.; McArdell, B. W.

2011-12-01

The ability of a debris flow to entrain or deposit sediment controls the downstream evolution of flow volume, and ultimately dictates both the geomorphic impact of the flow and the potential hazard that it represents. Our understanding of the patterns of, and controls on, such flow volume changes remains extremely limited, however, partly due to a poor mechanistic grasp of the interactions between debris flows and their bed and banks. In addition, we lack a good understanding of the cumulative long-term effects of sequences of flows in a single catchment-fan system. Here we begin to address these issues by using repeated terrestrial laser scanning (TLS) to characterize the detailed surface change associated with the passage of multiple debris flows on the Illgraben fan, Switzerland. We calculate surface elevation change along a 300 m study reach, and from this derive the downfan rate of flow volume change, or lag rate; for comparison, we also derive the spatially-averaged lag rate over the entire ~2 km length of the fan. Lag rates are broadly comparable over both length scales, indicating that flow behavior does not vary significantly across the fan for most flows, but importantly we find that flow volume at the fan head is a poor predictor of volume at the fan toe. The sign and magnitude of bed elevation change scale with local flow depth; at flow depths < 2 m, erosion and deposition are approximately equally likely, but erosion becomes increasingly dominant for flow depths > 2 m. On the Illgraben fan, this depth corresponds to a basal shear stress of 3-4 kPa. Because flow depth is in part a function of channel cross-sectional topography, which varies strongly both within and between flows, this result indicates that erosion and deposition are likely to be highly dynamic. The dependence of flow volume change on both the channel topography and the flow history may thus complicate efforts to predict debris-flow inundation areas by simple flow routing. We then apply a 2d numerical model of debris-flow fan evolution to explore the key controls on debris-flow routing and topographic development over sequences of multiple flows. We find that fan topographic roughness plays an important role in both channel development and fan surface stability. We also find that, while first-order fan shape is largely insensitive to the input flow sequence, second-order variables such as the pattern of surface exposure ages and the distribution of channel characteristics hold more promise as robust recorders of past flow conditions. Further work is needed to understand the degree to which the TLS-derived (and Illgraben-specific) relationship between bed elevation change and flow depth can be applied in different settings, and to elucidate the role played by coarse debris in controlling patterns of erosion and deposition.

Seismic stratigraphy and late Quaternary shelf history, south-central Monterey Bay, California

USGS Publications Warehouse

Chin, J.L.; Clifton, H.E.; Mullins, H.T.

1988-01-01

The south-central Monterey Bay shelf is a high-energy, wave-dominated, tectonically active coastal region on the central California continental margin. A prominent feature of this shelf is a sediment lobe off the mouth of the Salinas River that has surface expression. High-resolution seismic-reflection profiles reveal that an angular unconformity (Quaternary?) underlies the entire shelf and separates undeformed strata above it from deformed strata below it. The Salinas River lobe is a convex bulge on the shelf covering an area of approximately 72 km2 in water depths from 10 to 90 m. It reaches a maximum thickness of 35 m about 2.5 km seaward of the river mouth and thins in all directions away from this point. Adjacent shelf areas are characterized by only a thin (2 to 5 m thick) and uniform veneer of sediment. Acoustic stratigraphy of the lobe is complex and is characterized by at least three unconformity-bounded depositional sequences. Acoustically, these sequences are relatively well bedded. Acoustic foresets occur within the intermediate sequence and dip seaward at 0.7?? to 2.0??. Comparison with sedimentary sequences in uplifted onshore Pleistocene marine-terrace deposits of the Monterey Bay area, which were presumably formed in a similar setting under similar processes, suggests that a general interpretation can be formulated for seismic stratigraphic patterns. Depositional sequences are interpreted to represent shallowing-upwards progradational sequences of marine to nonmarine coastal deposits formed during interglacial highstands and/or during early stages of falling sea level. Acoustic foresets within the intermediate sequence are evidence of seaward progradation. Acoustic unconformities that separate depositional sequences are interpreted as having formed largely by shoreface planation and may be the only record of the intervening transgressions. The internal stratigraphy of the Salinas River lobe thus suggests that at least several late Quaternary regressions and transgressions may be recorded under the present shelf. This record may represent the last major eustatic cycle of sea level, an interval not observed in uplifted onshore Pleistocene marine terraces. ?? 1988.

Upper Albian to Lower Turonian deposits and associated breccias along the Dahar cuestas (southeastern Tunisia): Origin and depositional environments

NASA Astrophysics Data System (ADS)

Krimi, Mabrouk; Ouaja, Mohamed; Zargouni, Fouad

2017-11-01

The carbonate Zebbag Formation of Upper Albian to Lower Turonian age which outcrops along the Dahar cuestas (south eastern Tunisia) includes several breccia intervals. The stratigraphic hierarchy of these breccia levels led to achieving a detailed sequential analysis within a spectrum of depositional environments extending from subtidal to inner to middle ramp settings. Six major transgressive/regressive sequences make up the stacking of the elementary sequences beginning with transgressive and/or storm wave breccias capped by desiccation and/or collapse breccias. The stratigraphic evolutionary history of the breccia facies are interpreted as the result of the interplay between eustatic and tectonic factors. This model is in accord with the tectonic activities common during Upper Albian-Lower Turonian responsible for the sequences onlapping.

Correcting names of bacteria deposited in National Microbial Repositories: an analysed sequence data necessary for taxonomic re-categorization of misclassified bacteria-ONE example, genus Lysinibacillus.

PubMed

Rekadwad, Bhagwan N; Gonzalez, Juan M

2017-08-01

A report on 16S rRNA gene sequence re-analysis and digitalization is presented using Lysinibacillus species (one example) deposited in National Microbial Repositories in India. Lysinibacillus species 16S rRNA gene sequences were digitalized to provide quick response (QR) codes, Chaose Game Representation (CGR) and Frequency of Chaose Game Representation (FCGR). GC percentage, phylogenetic analysis, and principal component analysis (PCA) are tools used for the differentiation and reclassification of the strains under investigation. The seven reasons supporting the statements made by us as misclassified Lysinibacillus species deposited in National Microbial Depositories are given in this paper. Based on seven reasons, bacteria deposited in National Microbial Repositories such as Lysinibacillus and many other needs reanalyses for their exact identity. Leaves of identity with type strains of related species shows difference 2 to 8 % suggesting that reclassification is needed to correctly assign species names to the analyzed Lysinibacillus strains available in National Microbial Repositories.

Metastable and equilibrium phase formation in sputter-deposited Ti/Al multilayer thin films

NASA Astrophysics Data System (ADS)

Lucadamo, G.; Barmak, K.; Lavoie, C.; Cabral, C., Jr.; Michaelsen, C.

2002-06-01

The sequence and kinetics of metastable and equilibrium phase formation in sputter deposited multilayer thin films was investigated by combining in situ synchrotron x-ray diffraction (XRD) with ex situ electron diffraction and differential scanning calorimetry (DSC). The sequence included both cubic and tetragonal modifications of the equilibrium TiAl3 crystal structure. Values for the formation activation energies of the various phases in the sequence were determined using the XRD and DSC data obtained here, as well as activation energy data reported in the literature.

Evolution Of Quaternary Stream Fan Deposits At The Confluences Of Turung Khola And Bembung Khola Of Middle Teesta Basin In Sikkim-Darjeeling Himalaya,India: A Tectonic - Climate Response

NASA Astrophysics Data System (ADS)

Lukram, I. M.

2007-12-01

Tributary fan deposits are well preserved on either side of the Teesta river in the non-glaciated middle part of the Himalayan valley lying in a tectonic region bounded by the MCT and MBT. The lithofacies characteristics and assemblage patterns of these deposits bear testimony to the effects of tectonic and climatic activities on the sedimentation process in the basin. Two tributary streams, with small catchments namely Turung Khola and Bembung Khola are important in this context. Three major fan lobes (F2, F1, and F0) are preserved at Turung Khola. In contrast, two fan lobes (F1,F0) are preserved at the confluence of the Bembung Khola. Terraces, floodplains, channel bars, chute bars are associated geomorphic features in this part of the Teesta basin. Landslides cover an area of 7% and 15% in the catchment of Turung Khola and Bembung Khola, respectively. Dense forest covers 24% and 12%; open forest covers 30% and 29 %; and scrubby vegetation covers 39% and 49% of the Turung Khola and Bembung Khola, respectively. The landslides mainly occur along the margins of the dense forest where they are active in every rainy season. Tributary longitudinal profiles and Hack profiles indicate a relationship between the knick points and high SL-Index values, where fault /thrust intersections are present. Active landslides and scarps are close to the major fault/thrust planes. Sediment characteristics of these fan deposits suggest that four types of depositional flows viz. debris flows, hyperconcentrated flows, sheet flows and channel flows laid down these sequences. The channel flow deposits are dominant (32%-54 %) in the fan sequence of the Turung Khola followed by sheet flow deposits (28.5%), hyperconcentrated flow deposits (26%) and debris flow deposits (12%), respectively. Hyperconcentrated flow deposits are dominant (44%) in the F1 sequence, whereas the active channel fanlobe is dominant (80%) in the channel flow deposits. The rest of the active channel sequence is composed of sheet flow deposits (20%). On the other hand, the major part (52%) of the F1 fanlobe of Bembung Khola is built up of debris flow deposits and F0 fanlobe is composed of channel flow deposits and flood sediment. From the above analysis, an evolutionary model of the deposition and incision at the tributary stream fan confluence is proposed. The insetting of the younger fan lobes into older fan lobe surfaces is an evidence of tectonic uplift in the region. The landform and their depositional pattern are a responds to link tectonic- climatic process systems; some depositional lithofacies assemblages are responses to climatic events.

Progress in faunal correlation of Late Cenozoic fluvial sequences 2000 4: the report of the IGCP 449 biostratigraphy subgroup

NASA Astrophysics Data System (ADS)

Schreve, D. C.; Keen, D. H.; Limondin-Lozouet, N.; Auguste, P.; Santisteban, Juan I.; Ubilla, M.; Matoshko, A.; Bridgland, D. R.; Westaway, R.

2007-11-01

Vertebrate and invertebrate faunal biostratigraphy is a well-tested method for establishing relative chronologies for fluviatile sequences that has proved useful in many parts of the world. The robust bones and teeth of large mammals are commonly found in fluviatile deposits, whereas small vertebrates can be readily recovered through systematic sieving of calcareous sediments, as can molluscs, the other major faunal group that has been used for biostratigraphical analysis of fluvial sequences. Because of their rapid and quantifiable rates of evolution, extinction, body mass change and dispersal during the Late Cenozoic, mammals are especially useful for ordering the fragmentary terrestrial sequence of interglacials and glacials, and proposing correlation with the global marine climatostratigraphic record. Other groups (e.g. reptiles and amphibians, ostracods) are as yet only in the initial stages of development as a dating tool, whereas some (e.g. fish, birds) still require substantial development in order to fully explore their utility. As part of IGCP 449, vertebrate and molluscan assemblages have made important contributions to datasets from a number of areas, notably northern France, central Germany, the Czech Republic and the Ukraine. Further south, mammalian assemblages have proved useful in separating discrete periods of climatic change in Iberia and Syria. At greater distances from the core area of fluvial biostratigraphical archives, significant contributions have come from South America (Uruguay River), South Africa (Vaal) and Australia (Riverine Plain and Lake Eyre drainage basin).

Postimpact deposition in the Chesapeake Bay impact structure: Variations in eustasy, compaction, sediment supply, and passive-aggressive tectonism

USGS Publications Warehouse

Kulpecz, A.A.; Miller, K.G.; Browning, J.V.; Edwards, L.E.; Powars, D.S.; McLaughlin, P.P.; Harris, A.D.; Feigenson, M.D.

2009-01-01

The Eyreville and Exmore, Virginia, core holes were drilled in the inner basin and annular trough, respectively, of the Chesapeake Bay impact structure, and they allow us to evaluate sequence deposition in an impact crater. We provide new high-resolution geochronologic (<1 Ma) and sequence-stratigraphic interpretations of the Exmore core, identify 12 definite (and four possible) postimpact depositional sequences, and present comparisons with similar results from Eyreville and other mid- Atlantic core holes. The concurrence of increases in ??18O with Chesapeake Bay impact structure sequence boundaries indicates a primary glacioeustatic control on deposition. However, regional comparisons show the differential preservation of sequences across the mid-Atlantic margin. We explain this distribution by the compaction of impactites, regional sediment-supply changes, and the differential movement of basement structures. Upper Eocene strata are thin or missing updip and around the crater, but they thicken into the inner basin (and offshore to the southeast) due to rapid crater infilling and concurrent impactite compaction. Oligocene sequences are generally thin and highly dissected throughout the mid-Atlantic region due to sediment starvation and tectonism, except in southeastern New Jersey. Regional tectonic uplift of the Norfolk Arch coupled with a southward decrease in sediment supply resulted in: (1) largely absent Lower Miocene sections around the Chesapeake Bay impact structure compared to thick sections in New Jersey and Delaware; (2) thick Middle Miocene sequences across the Delmarva Peninsula that thin south of the Chesapeake Bay impact structure; and (3) upper Middle Miocene sections that pinch out just north of the Chesapeake Bay impact structure. Conversely, the Upper Miocene-Pliocene section is thick across Virginia, but it is poorly represented in New Jersey because of regional variations in relative subsidence. ?? 2009 The Geological Society of America.

Coating multilayer material with improved tribological properties obtained by magnetron sputtering

NASA Astrophysics Data System (ADS)

Mateescu, A. O.; Mateescu, G.; Balasoiu, M.; Pompilian, G. O.; Lungu, M.

2017-02-01

This work is based on the Patent no. RO 128094 B1, granted by the Romanian State Office for Inventions and Trademarks. The goal of the work is to obtain for investigations tribological coatings with multilayer structure with improved tribological properties, deposited by magnetron sputtering process from three materials (sputtering targets). Starting from compound chemical materials (TiC, TiB2 and WC), as sputtering targets, by deposition in argon atmosphere on polished stainless steel, we have obtained, based on the claims of the above patent, thin films of multilayer design with promising results regarding their hardness, elastic modulus, adherence, coefficient of friction and wear resistance. The sputtering process took place in a special sequence in order to ensure better tribological properties to the coating, comparing to those of the individual component materials. The tribological properties, such as the coefficient of friction, are evaluated using the tribometer test.

Deposition and weathering of Asian dust in Korea

NASA Astrophysics Data System (ADS)

Jeong, G.

2013-12-01

Paleolithic stone artifacts in Korea typically occur in brown clay-silt (BCS) sequences. The origin and depositional environment of these sequences are important for reconstructing the paleoenvironment as well as for establishing chronologies of artifact-bearing stratigraphic units. We investigated four BCS-bearing sections in foothills and river and marine terraces in Korea by applying quantitative mineralogical, geochemical, microtextural, and K-Ar isotopic methods. In all four sections, the lower units are colluvial and fluvial deposits strongly influenced by diverse local lithology, whereas the upper units are characterized by BCS units. Mineralogical/geochemical compositions, grain sizes, and colors converge into common properties in the upper BCS units in all sections. These common properties are consistent with the eastward trends of increasing weathering degree and grain size fining throughout the loess-paleosol sections of the Chinese Loess Plateau (CLP). K-Ar detrital ages of the sections also converge upward into a narrow range similar to the age ranges of the loess and paleosols in the CLP. The top BCS unit in the Jeongok section, the thickest section, is underlain by an additionally weathered BCS unit, with strong red chroma indicating a change from warm to cold climate. We did not observe any clear evidence of climatic changes in other thinner sections, which may be due to a superposition of cold-stage accumulation and warm-stage deep weathering. The common properties of the BCSs in Korean sections and their relationship to the CLP loess and paleosols indicate widespread deposition of Asian dust and subsequent weathering in the late Quaternary, forming BCS sequences. In this respect, the BCS sequences investigated here are considered to be the additionally weathered equivalents of the CLP loess-paleosol sequences, having been exposed to the high annual precipitation of the Korean Peninsula. Given the wide distribution of BCS sequences at Paleolithic sites throughout the Peninsula, the findings of this study are important for the ongoing debate surrounding the depositional environments of the Paleolithic deposits, and provide a foundation for the establishment of the chronological framework of the Paleolithic artifact-bearing layers and lithic assemblages.

Deposition and weathering of Asian dust in Paleolithic sites, Korea

NASA Astrophysics Data System (ADS)

Jeong, Gi Young; Choi, Jeong-Heon; Lim, Hyoun Soo; Seong, Chuntaek; Yi, Seon Bok

2013-10-01

Paleolithic stone artifacts in Korea typically occur in brown clay-silt (BCS) sequences. The origin and depositional environment of these sequences are important for reconstructing the paleoenvironment as well as for establishing chronologies of artifact-bearing stratigraphic units. We investigated four BCS-bearing sections in foothills and river and marine terraces in Korea by applying quantitative mineralogical, geochemical, microtextural, and K-Ar isotopic methods. In all four sections, the lower units are colluvial and fluvial deposits strongly influenced by diverse local lithology, whereas the upper units are characterized by BCS units. Mineralogical/geochemical compositions, grain sizes, and colors converge into common properties in the upper BCS units in all sections. These common properties are consistent with the eastward trends of increasing weathering degree and grain size fining throughout the loess-paleosol sections of the Chinese Loess Plateau (CLP). K-Ar detrital ages of the sections also converge upward into a narrow range similar to the age ranges of the loess and paleosols in the CLP. The top BCS unit in the Jeongok section, the thickest section, is underlain by an additionally weathered BCS unit, with strong red chroma indicating a change from warm to cold climate. We did not observe any clear evidence of climatic changes in other thinner sections, which may be due to a superposition of cold-stage accumulation and warm-stage deep weathering. The common properties of the BCSs in Korean sections and their relationship to the CLP loess and paleosols indicate widespread deposition of Asian dust and subsequent weathering in the late Quaternary, forming BCS sequences. In this respect, the BCS sequences investigated here are considered to be the additionally weathered equivalents of the CLP loess-paleosol sequences, having been exposed to the high annual precipitation of the Korean Peninsula. Given the wide distribution of BCS sequences at Paleolithic sites throughout the Peninsula, the findings of this study are important for the ongoing debate surrounding the depositional environments of the Paleolithic deposits, and provide a foundation for the establishment of the chronological framework of the Paleolithic artifact-bearing layers and lithic assemblages.

The use of sequence-based SSR mining for the development of a vast collection of microsatellites in Aquilegia Formosa

Treesearch

Brandon Schlautman; Vera Pfeiffer; Juan Zalapa; Johanne Brunet

2014-01-01

Numerous microsatellite markers were developed for Aquilegia formosafrom sequences deposited within the Expressed Sequence Tag (EST), Genomic Survey Sequence (GSS), and Nucleotide databases in NCBI. Microsatellites (SSRs) were identified and primers were designed for 9 SSR containing sequences in the Nucleotide database, 3803 sequences in the EST...

Rapid transport of ash and sulfate from the 2011 Puyehue-Córdon Caulle (Chile) eruption to West Antarctica

NASA Astrophysics Data System (ADS)

Dowd, E.; Koffman, B. G.; Osterberg, E. C.; Ferris, D. G.; Hartman, L.; Wheatley, S.; Kurbatov, A.; Wong, G. J.; Markle, B. R.; Dunbar, N. W.; Kreutz, K. J.; Yates, M. G.

2017-12-01

The VEI 5 eruption of the Puyehue-Cordón Caulle volcanic complex (PCC) in central Chile, which began 4 June 2011, provides a rare opportunity to assess the rapid transport and deposition of sulfate and ash from a mid-latitude volcano to the Antarctic ice sheet. We present sulfate, microparticle concentrations of fine-grained ( 5 μm diameter) tephra, and geochemistry, which document the depositional sequence of volcanic products from the PCC eruption in West Antarctic snow and shallow firn. From the depositional phasing and duration of ash and sulfate peaks, we infer that transport occurred primarily through the troposphere but that ash and sulfate transport were decoupled. We use Hysplit back-trajectory modeling to assess circulation conditions in the weeks following the eruption, and find that atmospheric conditions favored mid-to-high latitude air parcel transport during 6-14 June and 4-18 July, 2011. We suggest that two discrete pulses of cryptotephra deposition relate to these intervals, and as such, constrain the sulfate transport and deposition lifespan to the 2-3 weeks following the eruption. Finally, we compare PCC depositional patterns to those of prominent low- and high-latitude eruptions in order to improve multiparameter-based efforts to identify "unknown source" eruptions in the ice core record. Our observations suggest that mid-latitude eruptions such as PCC can be distinguished from explosive tropical eruptions by differences in ash/sulfate phasing and in the duration of sulfate deposition, and from high-latitude eruptions by differences in particle size distribution and in cryptotephra geochemical composition.

Rapid transport of ash and sulfate from the 2011 Puyehue-Cordón Caulle (Chile) eruption to West Antarctica

NASA Astrophysics Data System (ADS)

Koffman, Bess G.; Dowd, Eleanor G.; Osterberg, Erich C.; Ferris, David G.; Hartman, Laura H.; Wheatley, Sarah D.; Kurbatov, Andrei V.; Wong, Gifford J.; Markle, Bradley R.; Dunbar, Nelia W.; Kreutz, Karl J.; Yates, Martin

2017-08-01

The Volcanic Explosivity Index 5 eruption of the Puyehue-Cordón Caulle volcanic complex (PCC) in central Chile, which began 4 June 2011, provides a rare opportunity to assess the rapid transport and deposition of sulfate and ash from a midlatitude volcano to the Antarctic ice sheet. We present sulfate, microparticle concentrations of fine-grained ( 5 μm diameter) tephra, and major oxide geochemistry, which document the depositional sequence of volcanic products from the PCC eruption in West Antarctic snow and shallow firn. From the depositional phasing and duration of ash and sulfate peaks, we infer that transport occurred primarily through the troposphere but that ash and sulfate transport were decoupled. We use Hybrid Single-Particle Lagrangian Integrated Trajectory back trajectory modeling to assess atmospheric circulation conditions in the weeks following the eruption and find that conditions favored southward air parcel transport during 6-14 June and 4-18 July 2011. We suggest that two discrete pulses of cryptotephra deposition relate to these intervals, and as such, constrain the sulfate transport and deposition lifespan to the 2-3 weeks following the eruption. Finally, we compare PCC depositional patterns to those of prominent low- and high-latitude eruptions in order to improve multiparameter-based efforts to identify "unknown source" eruptions in the ice core record. Our observations suggest that midlatitude eruptions such as PCC can be distinguished from explosive tropical eruptions by differences in ash/sulfate phasing and in the duration of sulfate deposition, and from high-latitude eruptions by differences in particle size distribution and in cryptotephra geochemical composition.

Environmental, depositional and cultural changes in the upper Pleistocene and early Holocene; the Cinglera del Capello Sequence (Capellades, Spain)

USGS Publications Warehouse

Vaquero, Manuel; Allué, Ethel; Bischoff, James L.; Burjachs, Francesc; Vallverdú, Josep

2013-01-01

The correlation between environmental and cultural changes is one of the primary archeological and paleoanthropological research topics. Analysis of ice and marine cores has yielded a high-resolution record of millennial-scale changes during the Late Pleistocene and Holocene eras. However, cultural changes are documented in low-resolution continental deposits; thus, their correlation with the millennial-scale climatic sequence is often difficult. In this paper, we present a rare occurrence in which a thick archeological sequence is associated with a high-resolution environmental record. The Cinglera del Capello is a tufa-draped cliff located in the northeastern Iberian Peninsula, 50 km west of Barcelona. This cliff harbors several rock-shelters with Late Pleistocene and Early Holocene deposits. Together, the deposits of four rock-shelters span from 7000 to 70,000 years ago and provide a high-resolution record of the environmental and human dynamics during this timespan. This record allows the correlation of the cultural and environmental changes. The multiproxy approach to the Cinglera evidence indicates that the main cultural stages of the Late Pleistocene and Early Holocene (Middle Paleolithic, Upper Paleolithic and Mesolithic) are associated with significant changes in the environmental and depositional contexts.

Sedimentology and High Resolution Sequence Stratigraphy of the Middle Jurassic Dhruma Formation Carbonates Outcrops in the Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Yousif, Ibrahim; Abdullatif, Osman; Makkawi, Mohammed; Abdulghani, Waleed

2017-04-01

This study investigates the microfacies and sequence stratigraphic frame work of the Middle Jurassic Dhruma Formation in outcrops in central Saudi Arabia. The study contributes to the efforts to understand and enhance local and regional stratigraphic relationship and correlation of the Jurassic carbonate sequences and their significance to reservoir description and prediction in the subsurcae. The study describes and characterizes the sedimentology, microfacies and the stratigraphy of Dhruma Formation from outcrop sections having a total thickness of 70 m. Detailed microfacies and high-resolution stratigraphical analysis were carried out to determine microfacies, cyclicity, sequences and staking pattern. The study revealed ten lithofacies namely: oolitic grainstone,bioclastic oolitic grainstone, oolitic grapestone, bioclastic grainstone,foraminiferal packstone, echinoderm packstone, peloidal packstone to grainstone,skeletal wackestone to packstone, mudstone, and marlstone.These lithofacies were grouped into five lithofacies associations that deposited on a carbonate ramp setting. The depositional environment ranging from low energy lagoonal setting to high-energy shoals and banks to low energy outer ramp setting. Five high-resolution composite sequences have been defined and each sequence is composed at the bottom of intercalated mudstone/wackestone that passing up into grainstone lithofacies.The composite sequences range in thickness from 7 to 15 m, while the parasequences range from 0.5 to 1.5 m. The composite sequences extend laterally for a distance of more than 350 m. The overall composite section shows a shallowing upward succession of the 4th to the 5th order high-resolution sequences.The dominant lithofacies are the grainy ones, which constitute 30%, 50% and 80% of the studied sections. Furthermore, the parasequences thickness and their bio-components are increasing towards the top. The muddy lithofacies intensively affected the vertical continuity of the lower reservoir interval compared to the upper interval. Detailed examination of thin-sections reflects a clear and well-developed reservoir interval in the uppermost part of the section, which is dominated by peloidal packstone and grainstone.The findings of this high-resolution outcrop analog might help to understand and predict lithofacies, stratigraphic heirachies and correlations of Dhruma Formation within the interwell spacing. Moreover, this study might also contribute to better reservoir description and assessment of its quality and architecture in subsurface equivalent reservoirs.

The A.D. 79 eruption as a future explosive scenario in the Vesuvian area: evaluation of associated risk

NASA Astrophysics Data System (ADS)

Lirer, Lucio; Munno, Rosalba; Postiglione, Immacolata; Vinci, Anna; Vitelli, Livia

Due to the lack of an effective policy of planning and prevention, over the past decades the area around Mt. Vesuvio has undergone a steady increase in population and uncontrolled housing development. Consequently, it has become one of the most hazardous volcanic areas in the world. In order to mitigate the damage that the impact of an explosive event would cause in the area, the Department of Civil Defense has worked out an Emergency Management Plan using the A.D. 1631 subplinian eruption as the most probable short-term event. However, from 25 000 years B.P. to present, the activity of the Somma-Vesuvio volcano has shown a sequence of eight eruptive cycles, which always began with a strong plinian eruption. In this paper we utilize the A.D. 79 eruption as an example of a potential large explosive eruption that might occur again at Vesuvio. A detailed tephrostratigraphic analysis of the eruption products was processed by a multivariate statistical analysis. This analysis proved useful for identifying marker layers in the sequences, thus allowing the recognition of some major phases of synchronous deposition and hence the definition of the chronological and spatial evolution of the eruption. By combining this reconstruction with land-use maps, a scenario is proposed with time intervals in the eruptive sequence similar to those reported in Pliny's letter. Thus, it was calculated that, after 7h from the start of the eruption, a total area of approximately 300km2 would be covered with the eruption products. In the following 11h, a total area of approximately 500km2 would be involved. The third and last phase of deposition would not cause significant variation in the total area involved, but it would bring about an increase in the thickness of the pyroclastic deposits in the perivolcanic area.

Cyclostratigraphy across a Mississippian carbonate ramp in the Esfahan-Sirjan Basin, Iran: implications for the amplitudes and frequencies of sea-level fluctuations along the southern margin of the Paleotethys

NASA Astrophysics Data System (ADS)

Bayet-Goll, Aram; Esfahani, Fariba Shirezadeh; Daraei, Mehdi; Monaco, Paolo; Sharafi, Mahmoud; Mohammadi, Amir Akbari

2018-03-01

The Tournaisian-Visean carbonate successions of the Esfahan-Sirjan Basin (ESB) from Sanandaj-Sirjan Zone, Iran, have been used to generate a sequence stratigraphic model that enhances facies characterization and improves paleoenvironmental interpretation of shallow marine successions deposited along the southern margin of the Paleotethys. Detailed facies analysis allowed to differentiate seven facies, which, in order of decreasing abundance, are: (1) shaly and marly, F1; (2) peloidal mudstones/wackestones, F2; (3) peloidal/bioclastic packstones, F3; (4) intraclastic/bioclastic packstones/grainstones, F4; (5) oolitic/bioclastic packstone/grainstone, F5; (6) sandy intraclastic/bioclastic grainstones, F6; (7) sandy oolitic/bioclastic grainstones, F7. The different facies can be grouped into three facies associations that correspond to different environments of a carbonate platform with ramp geometry (homoclinal), from outer ramp (F1 and F2), mid-ramp (F3, F4 and F6) to inner ramp areas (F5 and F7). Meter-scale cycles are the basic building blocks of shallow marine carbonate successions of the Tournaisian-Viséan ramp of the ESB. Small-scale cycles are stacked into medium-scale cycles that in turn are building blocks of large-scale cycles. According to the recognized facies and the stacking pattern of high-frequency cycles across the ramp, five large-scale cycles in the southeastern outcrops (Tournaisian-Viséan) and three large-scale cycles in the northwest outcrops (Viséan) related to eustatic sea-level changes can be recognized. The overall retrogradational nature of the carbonate ramp, illustrated by both vertical facies relationships and the stacking patterns of high-frequency cycles within the third-order cycles, implies that the deposition of the Tournaisian-Viséan successions mainly took place under a long-term transgressive sea-level trend. The stratigraphic architectural style of the sequences, characterized by the lack of lowstand deposits and exposure surfaces, associated with the evidence of progressive increase in the proportion of backstepping of facies belts across bounding surfaces and predominant subtidal characteristics, is in accordance with the long-term transgressive sea-level trend and greenhouse conditions during the Tournaisian-Viséan. The continued transgression on this broad shelfal platform could lead to the shutdown of the shallow water carbonate factory, reduction in sediment supply or sediment transport towards the offshore setting and the development of give-up sequences. The association of transgressive events with the deposition of thick open-marine marls/shales is a common feature in Tournaisian to Viséan times of the southern margin of the Paleotethys.

Submarine fan facies of Upper Cretaceous Strata, Southern San Rafael Mountains, Santa Barbara County, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toyne, C.D.

1986-04-01

A 2900-m thick Campanian-Maestrichtian(.) turbidite sequence in Upper Mono Creek Canyon is interpreted to be a progradational submarine fan complex comprised of outer fan, middle fan, inner fan, and slope facies. The basal 600 m of the section consists of thinly bedded, laterally continuous fine sandstones, siltstones, and mudstones (mainly Mutti and Ricci Lucci facies D), interpreted to be outer fan interlobe and lobe-fringe deposits. These are punctuated by infrequent medium to very thickly bedded, flat-based, fine to coarse sandstones (facies C and B), which commonly coarsen and thicken upward, and are interpreted to be depositional lobes. Overlying these depositsmore » are approximately 1400 m of middle fan deposits composed of frequent lenticular, commonly channelized and amalgamated, thickly bedded, fine to very coarse sandstones (facies C and B) organized in fining- and thinning-upward sequences, interpreted to be braided-channel deposits. These alternate with less common nonchannelized coarsening- and thickening-upward sequences suggestive of lobe-apical cycles. These multistory sand deposits are nested within thick intervals of fine sandstones, siltstones, and mudstones (facies C and D), interpreted to be levee, crevasse-splay, and interchannel deposits. Interfingered with and overlying these deposits are approximately 500 m of fining- and thinning-upward or noncyclic, erosionally based, commonly amalgamated, very thickly bedded, medium to very coarse sandstones, pebbly sandstones, and conglomerates (facies A and B), interpreted to be inner fan deposits. Intercalated within this facies, infrequent, laterally discontinuous, thin to thickly bedded, fine to coarse sandstones, siltstones, and mudstones exist, interpreted to be interchannel, levee, and possibly channel-fill deposits.« less

The transitional depositional environment and sequence stratigraphy of Chasma Boreale

NASA Astrophysics Data System (ADS)

Brothers, S. C.; Kocurek, G.

2018-07-01

The depositional system within Chasma Boreale is unique in that it contains active aeolian environments, expressed as dune fields, and active cryosphere environments, present as layered ice deposits, as well as environments that transition between these. This work presents a new analysis of the Chasma Boreale sediment system that creates an interpretative framework addressing: (a) controls on the balance between aeolian and cryospheric processes in the modern depositional system, (b) the stratigraphic architecture of related sedimentary deposits, and (c) processes of sediment accumulation and preservation. Images from Context Camera (CTX; 6 m/pixel) are used to classify and map sedimentary environments, surfaces, and deposits on the reentrant floor, to refine the established geologic map of the reentrant, and to infer the stratigraphic record of the accumulation from Chasma Boreale's depositional system. A spectrum of sedimentary environments occurring between those dominated by aeolian and by cryospheric processes are identified. Through time, the boundaries of these sedimentary environments have shifted, resulting in complex lateral changes in the configuration of sedimentary environments on the reentrant's floor. Vertically, the stratigraphic record is characterized by the punctuation of sandy aeolian deposits by icy surfaces that indicate episodes of ice growth that preserve underlying deposits, resulting in accumulation. Stabilized icy surfaces occur at multiple vertical (temporal) scales and lateral extents, suggesting the influence of both regional climate change due to allogenic forcing, as well as autogenic dynamics within the transitional system. These observations demonstrate that the Chasma Boreale accumulation can be interpreted in an aeolian sequence stratigraphic framework. This work contributes the first detailed description of the processes forming polar aeolian sequences, with an emphasis on the competing and complementary dynamics between aeolian and cryospheric systems.

Late Holocene stratigraphy of the Tetimpa archaeological sites, northeast flank of Popocatepetl volcano, central Mexico

USGS Publications Warehouse

Panfil, M.S.; Gardner, T.W.; Hirth, K.G.

1999-01-01

Late Holocene (240 km2 on the east side of the volcano with >25 cm of tephra. Lavas from eruptive sequence I dammed drainage in the lowland area near the town of San Nicolas and caused local upstream deposition of as much as 30 m of lacustrine silts, clays, and sands. These lacustrine deposits record an eruptive hiatus for the Tetimpa area of about 750 14C yr: between ca. 2100 and ca. 1350 yr B.P., no major tephras were deposited in the Tetimpa area. In upland areas, this time period is represented by an unconformity and by Entisols formed in the top of pumice deposits and lavas from eruptive sequence I. Artifacts, agricultural furrows, and dwellings record human reoccupation of this surface. At the end of this hiatus, several lahars were deposited above the lacustrine sequence and locally above the Entisol in upland positions adjacent to streams. Between ca. 1350 and ca. 1200 yr B.P., tephras from eruptive sequence II buried these paleosols, occupation sites, lacustrine sediments, and lahars. Andesitic (~62% SiO2) pumice lapilli deposits in the Tetimpa area record three pumice-fall eruptions directed northeast and east of the crater. The first and smallest of these (maximum Tetimpa area thickness = 12 cm; >52 km2 covered by >25 cm) took place at ca. 1350 yr B.P. and was accompanied by pyroclastic surge events preserved in the Tetimpa area by charcoal, sand waves, and cross-stratified sand-sized tephra. At ca. 1200 yr B.P., the products of two Plinian-style events and additional pyroclastic surges reached the Tetimpa area. The largest of these tephra-fall events covered the Tetimpa area with 0.5-1 m of tephra and blanketed an area of >230 km2 with a thickness of >25 cm. The Tetimpa record confirms two of the four periods of explosive volcanism recognized by studies conducted around Popocatepetl in the past 30 yr. Eruptive sequence I corresponds to the explosive period between 2100 and 2500 yr B.P., and eruptive sequence II corresponds to the period between 900 and 1400 yr B.P. The archaeology and lacustrine stratigraphy of the Tetimpa area help constrain the timing of the Plinian phase of eruptive sequence I to ca. 2100 yr B.P. and suggest that the pumice-fall eruptions of eruptive sequence II took place in at least two intervals between ca. 1350 and ca. 1200 yr B.P.

Depositional setting and early diagenesis of the dinosaur eggshell-bearing Aren Fm at Bastus, Late Campanian, south-central Pyrenees

NASA Astrophysics Data System (ADS)

Díaz-Molina, Margarita; Kälin, Otto; Benito, M. Isabel; Lopez-Martinez, Nieves; Vicens, Enric

2007-07-01

The Late Cretaceous Aren Fm exposed north of Bastus in the Tremp Basin (south-central Pyrenees) preserves an excellent record of dinosaur eggs laid in a marine littoral setting. Different from other cases reported in literature, at the Bastus site the preferential nesting ground was original beach sand. The coastal deposits of Aren Fm can be grouped into four facies assemblages, representing respectively shoreface, beachface, beach ridge plain and backbarrier lagoon environments. Shoreface deposits include fine- to coarse-grained hybrid arenites and subordinate quartz-dominated conglomerates with ripple structures of wave and wave-current origin. Beachface deposits are mainly storm beach conglomerates, but parallel-laminated foreshore arenites locally occur. Backbarrier lagoon deposits comprise of washover sandy conglomerates that grade laterally into sandy lime mudstones, biomicrites and marls. Beach ridge sediment, wherein the bulk of dinosaur eggs and eggshell debris occurs, predominantly is a reddish hybrid arenite that has undergone a complex early diagenetic evolution, including marine and meteoric cementation followed by soil development. The reddish arenites overlie wave-dominated shoreface deposits and in places pass laterally into lagoonal deposits. They originally formed shore ridges, that became stabilized during progradational episodes by pedogenesis (beach ridge, sensu [Otvos, E.G., 2000. Beach ridges—definitions and significance. Geomorphology 32, 83-108.]), which also affected the dinosaur eggs. The eggshell-bearing beach ridge arenites are typically preserved at the top of parasequences forming the systems tracts of a third-order sequence. Thick packages of this facies resulted from aggradation of barrier/beach ridge deposits, whose preservation below surfaces of transgressive erosion was favoured by incipient lithification.

Dolni Vestonice (Czech Republic) an intermédiate loess series between Western and eastern European records

NASA Astrophysics Data System (ADS)

Rousseau, D.; Antoine, P.; Hatte, C.; Lagroix, F.; Fuchs, M.; Moine, O.; Gauthier, C.; Svoboda, J.; Lisa, L.

2010-12-01

Previous investigations on western and eastern European loess series have shown similarities at least for the main loess deposition during the last climate cycle, recording North-Atlantic abrupt climate changes, the Dansgaard-Oeschger and Heinrich events. To address the question of how such record occurred through modeling experiments (Sima et al., QSR, 2009), we need reference series located in an intermediary position between the Nussloch (Germany - Antoine et al, QI 2001, QSR, 2009; Rousseau et al, GRL 2007) and Stayky (Ukraine -Rousseau et al, Clim Past D 2010) loess series at about 50°N latitude, location of the main deposits. The key sequence of Dolni Vestonice in southern Czech Republic, had been investigated previously and described by many authors since 1961, and more especially by G Kukla and B Klima. Here we present the preliminary results of the new study of this key sequence by a multidisciplinary study, supported by ANR-ACTES project, combining the detailed stratigraphy, AMS 14C and IRSL dating, rock magnetic property, grain size, d13C and mollusks analyses. We applied the same sampling protocol than previously developed, by carefully cleaning the sequence on a vertical panel, 15m high and 5m wide in order to have parallel samples (on continuous columns) easily comparable. The results show similar patterns, high frequency variations of the different proxies in the upper part of the record corresponding to MIS 3 and 2, as observed in western and eastern European sequences supporting then our assumption of the recording of N Atlantic abrupt changes over Europe. Other interesting variations are clearly demonstrated for every proxy making these results remarkable new data for individual in deep studies. Moreover our detailed investigation also shows new data about abrupt dust events, markers, in the lower part of the sequence, and previously interpreted as strong dust events, and how they appear within sedimentary cycles linked to the cyclicity at the base of the last climate cycle.

Open resource metagenomics: a model for sharing metagenomic libraries.

PubMed

Neufeld, J D; Engel, K; Cheng, J; Moreno-Hagelsieb, G; Rose, D R; Charles, T C

2011-11-30

Both sequence-based and activity-based exploitation of environmental DNA have provided unprecedented access to the genomic content of cultivated and uncultivated microorganisms. Although researchers deposit microbial strains in culture collections and DNA sequences in databases, activity-based metagenomic studies typically only publish sequences from the hits retrieved from specific screens. Physical metagenomic libraries, conceptually similar to entire sequence datasets, are usually not straightforward to obtain by interested parties subsequent to publication. In order to facilitate unrestricted distribution of metagenomic libraries, we propose the adoption of open resource metagenomics, in line with the trend towards open access publishing, and similar to culture- and mutant-strain collections that have been the backbone of traditional microbiology and microbial genetics. The concept of open resource metagenomics includes preparation of physical DNA libraries, preferably in versatile vectors that facilitate screening in a diversity of host organisms, and pooling of clones so that single aliquots containing complete libraries can be easily distributed upon request. Database deposition of associated metadata and sequence data for each library provides researchers with information to select the most appropriate libraries for further research projects. As a starting point, we have established the Canadian MetaMicroBiome Library (CM(2)BL [1]). The CM(2)BL is a publicly accessible collection of cosmid libraries containing environmental DNA from soils collected from across Canada, spanning multiple biomes. The libraries were constructed such that the cloned DNA can be easily transferred to Gateway® compliant vectors, facilitating functional screening in virtually any surrogate microbial host for which there are available plasmid vectors. The libraries, which we are placing in the public domain, will be distributed upon request without restriction to members of both the academic research community and industry. This article invites the scientific community to adopt this philosophy of open resource metagenomics to extend the utility of functional metagenomics beyond initial publication, circumventing the need to start from scratch with each new research project.

Open resource metagenomics: a model for sharing metagenomic libraries

PubMed Central

Neufeld, J.D.; Engel, K.; Cheng, J.; Moreno-Hagelsieb, G.; Rose, D.R.; Charles, T.C.

2011-01-01

Both sequence-based and activity-based exploitation of environmental DNA have provided unprecedented access to the genomic content of cultivated and uncultivated microorganisms. Although researchers deposit microbial strains in culture collections and DNA sequences in databases, activity-based metagenomic studies typically only publish sequences from the hits retrieved from specific screens. Physical metagenomic libraries, conceptually similar to entire sequence datasets, are usually not straightforward to obtain by interested parties subsequent to publication. In order to facilitate unrestricted distribution of metagenomic libraries, we propose the adoption of open resource metagenomics, in line with the trend towards open access publishing, and similar to culture- and mutant-strain collections that have been the backbone of traditional microbiology and microbial genetics. The concept of open resource metagenomics includes preparation of physical DNA libraries, preferably in versatile vectors that facilitate screening in a diversity of host organisms, and pooling of clones so that single aliquots containing complete libraries can be easily distributed upon request. Database deposition of associated metadata and sequence data for each library provides researchers with information to select the most appropriate libraries for further research projects. As a starting point, we have established the Canadian MetaMicroBiome Library (CM2BL [1]). The CM2BL is a publicly accessible collection of cosmid libraries containing environmental DNA from soils collected from across Canada, spanning multiple biomes. The libraries were constructed such that the cloned DNA can be easily transferred to Gateway® compliant vectors, facilitating functional screening in virtually any surrogate microbial host for which there are available plasmid vectors. The libraries, which we are placing in the public domain, will be distributed upon request without restriction to members of both the academic research community and industry. This article invites the scientific community to adopt this philosophy of open resource metagenomics to extend the utility of functional metagenomics beyond initial publication, circumventing the need to start from scratch with each new research project. PMID:22180823

Spatiotemporal sedimentological and petrophysical characterization of El Gueria reservoir (Ypresian) in sFAX and Gulf of Gabes Basins (SE-Tunisia)

NASA Astrophysics Data System (ADS)

Nadhem, Kassabi; Zahra, Njahi; Ménendez, Béatriz; Salwa, Jeddi; Jamel, Touir

2017-06-01

El Gueria carbonate Formation (Ypresian) in Tunisia is a proven hydrocarbon reservoir. In the Gulf of Gabes, El Gueria reservoir consists mainly of a nummulitic limestone which is developed in an inner shelf environment. In order to characterize the depositional facies evolution and the petrophysical parameters, and to understand the origin of heterogeneity of El Gueria reservoir, we firstly conducted a sedimentological and a sequence stratigraphy study of this Formation in more than 10 wells especially in P1, then we established a detailed petrophysical study of El Gueria reservoir in P1, P3c and P7d cores. Based on lithostratigraphic and gamma ray correlations of an important number of wells in the study area, a detailed sedimentological study has been established. This latter shows that: (i): The Ypresien deposits are deposited in an inner shelf (El Gueria Formation) in the south and in an outer shelf (Boudabbous Formation) in the north of the study area with the form of horsts and grabens, (ii): 3 distinct members and 7 principal facies within El Gueria Formation have been distinguished. The coupling of data logging and data of the P1 core shows that the El Gueria deposits include 10 transgressive-regressive depositional sequences, while showing from bottom to top a broad regressive tendancy from a subtidal domain during the early Ypresian to an intertidal domain during the middle Ypresian reaching the supratidal environnement during the late Ypresian-early Lutetian. The petrophysical parameters (porosity and permeability) of El Gueria reservoir vary in time and space (laterally and vertically variation) following the deposit environment variation. Particularly, the porosity variation is controlled by eustatic cycles so that high porosities are linked with transgressive phases and low porosities with regressive phases. In addition, the vertical evolution of porosity through the El Gueria reservoir varies following the (i) deposit environments, (ii) type and morphology of nummulites such as large nummulites are more porous than small nummulites and nummilithoclastes (iii) matrix and cement such as micrite are more porous than sparite (iv) microfacies and diagenetic structures (Fractures, stylolithic seals …) such as the fractured wackstone are the most porous and permeable.

Apparatus for improved DNA sequencing

DOEpatents

Douthart, R.J.; Crowell, S.L.

1996-05-07

This invention is a means for the rapid sequencing of DNA samples. More specifically, it consists of a new design direct blotting electrophoresis unit. The DNA sequence is deposited on a membrane attached to a rotating drum. Initial data compaction is facilitated by the use of a machined multi-channeled plate called a ribbon channel plate. Each channel is an isolated mini gel system much like a gel filled capillary. The system as a whole, however, is in a slab gel like format with the advantages of uniformity and easy reusability. The system can be used in different embodiments. The drum system is unique in that after deposition the drum rotates the deposited DNA into a large non-buffer open space where processing and detection can occur. The drum can also be removed in toto to special workstations for downstream processing, multiplexing and detection. 18 figs.

Apparatus for improved DNA sequencing

DOEpatents

Douthart, Richard J.; Crowell, Shannon L.

1996-01-01

This invention is a means for the rapid sequencing of DNA samples. More specifically, it consists of a new design direct blotting electrophoresis unit. The DNA sequence is deposited on a membrane attached to a rotating drum. Initial data compaction is facilitated by the use of a machined multi-channeled plate called a ribbon channel plate. Each channel is an isolated mini gel system much like a gel filled capillary. The system as a whole, however, is in a slab gel like format with the advantages of uniformity and easy reusability. The system can be used in different embodiments. The drum system is unique in that after deposition the drum rotates the deposited DNA into a large non-buffer open space where processing and detection can occur. The drum can also be removed in toto to special workstations for downstream processing, multiplexing and detection.

Shelf-geometry response to changes in relative sea level on a mixed carbonate siliciclastic shelf in the Guyana Basin

NASA Astrophysics Data System (ADS)

Campbell, A. Ewan

2005-04-01

Differences in the shelf-margin geometry for various depositional regimes show how siliciclastic and carbonate margins respond differently to changes in accommodation space. During the Cenozoic, sequences of carbonate and siliciclastic sediment were deposited in the Guyana Basin on the passive continental margin of NE South America. Study of the sequence geometries reveal significantly different geometric responses to changes in relative sea level of intervals dominated by carbonates to intervals dominated by siliciclastics. Using the geometrical shelf break as a reference point, aggradation and progradation rates for the carbonate and siliciclastic depositional systems were measured. In siliciclastics, the lateral position of the margin remains roughly stationary with relative sea-level rises in the order of 30 m/My. At higher rates the margin retreats at lower rates it progrades. Carbonate margins remain stationary or slightly progradational even with relative sea-level rises of up to 100 m/My, the fastest rates observed in this study. This illustrates the strong tendency of carbonate platforms to stack their margins and keep up with relative rises in sea level, rather than gradually retreat landward as do siliciclastics. This observation may explain why carbonate platforms preferentially try to defend a margin prior to ultimate backstepping. The high aggradation potential of carbonate margins also gives onlap and downlap termination patterns on seismic profiles where carbonate platforms develop on sloping siliciclastic shelves. The resulting unconformities are a result of differences in sediment dispersal between the two systems and not necessarily from changes of relative sea level.

Optimising the use of marine tephrochronology in the North Atlantic: a detailed investigation of the Faroe Marine Ash Zones II, III and IV

NASA Astrophysics Data System (ADS)

Griggs, Adam J.; Davies, Siwan M.; Abbott, Peter M.; Rasmussen, Tine L.; Palmer, Adrian P.

2014-12-01

Tephrochronology is central to the INTIMATE goals for testing the degree of climatic synchroneity during abrupt climatic events that punctuated the last glacial period. Since their identification in North Atlantic marine sequences, the Faroe Marine Ash Zone II (FMAZ II), FMAZ III and FMAZ IV have received considerable attention due to their potential for high-precision synchronisation with the Greenland ice-cores. In order to optimise the use of these horizons as isochronous markers, a detailed re-investigation of their geochemical composition, sedimentology and the processes that deposited each ash zone is presented. Shard concentration profiles, geochemical homogeneity and micro-sedimentological structures are investigated for each ash zone preserved within core JM11-19PC, retrieved from the southeastern Norwegian Sea on the central North Faroe Slope. This approach allows a thorough assessment of primary ash-fall preservation and secondary depositional features and demonstrates its value for assessing depositional integrity in the marine environment. Results indicate that the FMAZ II and IV are well-resolved primary deposits that can be used as isochrons for high-precision correlation studies. We outline key recommendations for future marine tephra studies and provide a protocol for optimising the application of tephrochronology to meet the INTIMATE synchronisation goals.

Mg/Ti multilayers: Structural and hydrogen absorption properties

NASA Astrophysics Data System (ADS)

Baldi, A.; Pálsson, G. K.; Gonzalez-Silveira, M.; Schreuders, H.; Slaman, M.; Rector, J. H.; Krishnan, G.; Kooi, B. J.; Walker, G. S.; Fay, M. W.; Hjörvarsson, B.; Wijngaarden, R. J.; Dam, B.; Griessen, R.

2010-06-01

Mg-Ti alloys have uncommon optical and hydrogen absorbing properties, originating from a “spinodal-like” microstructure with a small degree of chemical short-range order in the atomic distribution. In the present study we artificially engineer short-range order by depositing Pd-capped Mg/Ti multilayers with different periodicities. Notwithstanding the large lattice mismatch between Mg and Ti, the as-deposited metallic multilayers show good structural coherence. On exposure to H2 gas a two-step hydrogenation process occurs with the Ti layers forming the hydride before Mg. From in situ measurements of the bilayer thickness Λ at different hydrogen pressures, we observe large out-of-plane expansions of Mg and Ti layers on hydrogenation, indicating strong plastic deformations in the films and a consequent shortening of the coherence length. On unloading at room temperature in air, hydrogen atoms remain trapped in the Ti layers due to kinetic constraints. Such loading/unloading sequence can be explained in terms of the different thermodynamic properties of hydrogen in Mg and Ti, as shown by diffusion calculations on a model multilayered systems. Absorption isotherms measured by hydrogenography can be interpreted as a result of the elastic clamping arising from strongly bonded Mg/Pd and broken Mg/Ti interfaces.

Biostratigraphy of Cretaceous-Paleogene marine succession, foraminiferal changes across the K/T boundary, sequence stratigraphy and response to sedimentary cyclicity in the Haymana Basin (Central Anatolia, Turkey)

NASA Astrophysics Data System (ADS)

Amirov, Elnur

2016-04-01

The aim of this study is to establish the planktonic foraminiferal biozonation, to construct the sequence stratigraphical framework and to determine the foraminiferal response to sedimentary cyclicity in the sedimentary sequence spanning Upper Cretaceous-Paleocene in the Haymana basin (Central Anatolia, Turkey). In order to achieve this study, the stratigraphic section was measured from sedimentary sequence of the Haymana, Beyobası and Yeşilyurt formations. The sedimentary sequence is mainly characterized by flyschoidal sequence that is composed of alternating of siliciclastic and carbonate units. On the account of the detailed taxonomic study of planktonic foraminifers, the biostratigraphic framework was established for the Maastrichtian-Paleocene interval. The biozonation includes 7 zones; Pseudoguembelina hariaensis, Pα, P1, P2, P3, P4 and P5 zones. The Cretaceous-Paleogene (K/P) boundary was delineated between the samples HEA-105 and 106. In order to construct the sequence-stratigraphical framework, the A, B, C and D-type meter-scale cycles were identified. Based on the stacking patterns of them, six depositional sequences, six third and two second order cycles were determined. Third order cycles coincide with the Global Sea Level Change Curve. On the account of the conducted petrographic analysis sandstone, mudstone, marl, limestone and muddy-limestone lithofacies were recorded in the studied samples. In order to demonstrate the response of foraminifers to cyclicity, quantitative analysis has been carried out by counting the individuals of planktonic, benthonic foraminifers and ostracods. The best response to sedimentary cyclicity was revealed from planktonic foraminifers. The average abundance of planktonic foraminifers increases in the transgressive systems tract and decreases in the highstand systems tract. Foraminifera are the most abundant marine protozoa in the benthic, epipelagic and pelagic realm. Because of the complexity and diversity of habitats, especially in the pelagic realm, planktonic foraminifera show high biodiversity and abundance as an effect of their different ecological requirements. Microfaunal analysis displays significant presence of foraminifers and an insignificant presence of ostracoda shells which represented by genera Leptocythere, Caspiella, Xestoleberis and etc. The foraminiferal assemblages of this sequence were determined in detail and quantitative analysis of them was carried out. By detail investigation of microfauna and determination of foraminifer species under the microscope, it was possible to pinpoint the C/P boundary in the studied section, which is indicating the mass extinctions of Cretaceous foraminifers represented by genera Archaeoglobigerina, Contusotruncana, Gansserina, Globigerinelloides, Globotruncana, Globorotalia, Hedbergella, Heterohelix, Planoglobulina and appearance of new small and non-keeled Danian species, represented by genera such as Chiloguembelina, Eoglobigerina, Globoconusa, Globanomalina, Igorina, Parvularugoglobigerina, Parasubbotina, Subbotina, Woodringina and etc. As a result of precise conducted research the significant bioevent has been revealed, namely that Hedbergella holmdelensis became extinct in Pα Zone.

Paleo-ocean environments before and after the Ordovician glaciation and the correlation with heterogeneous marine black shale: a stratigraphic case study of Wufeng-Longmaxi formation in Fuling, Sichuan basin, SW China

NASA Astrophysics Data System (ADS)

Lu, Yangbo; Hao, Fang; Lu, Yongchao

2017-04-01

The discovery of Fuling gas field in the Sichuan basin led China shale gas exploration to an unprecedented boom. The most important shale gas plays are the upper Ordovician Wufeng formation and Lower Silurian Longmaxi formation which demonstrate intriguing characteristics which are comprising of stable regional distribution, high abundance of organic matter, high thermal maturity and high brittle mineral content etc. As the Ordovician-Silurian transition was a critical interval in Earth's history marked by dramatic climatic, oceanic, and biological turnovers; these two advantageous organic rich shale deposited before and after Hirnantian glaciation are showing differences in many aspects. In this study, the stratigraphy and lithofacies within the stratigraphy framework of the upper Ordovician Wufeng formation and Lower Silurian Longmaxi formation in Fuling were quantitatively analyzed based on outcrops, cores, well logs data, and geochemical proxies. A total of three third-order sequences were divided based on the recognition of four third-order boundaries. The Wufeng Formation is equivalent to a third-order sequence and is subdivided into a transgressive system tract (TST) (black shale of lower Wufeng Formation) and a highstand system tract (HST) (Guanyinqiao Member of upper Wufeng Formation). Long-1 Member is equivalent to a third-order sequence and is subdivided into a TST, an early highstand system tract (EHST) and a late highstand system tract (LHST); Long-2 and Long-3 Member are combined to be one third-order sequence and is subdivided into a lowstand system tract (LST), a TST and a HST. Sequence development and sedimentary environment characteristics were analyzed within each system tract unit. TOC% was correlated to V/Cr and EF-Ni respectively within each system tract unit, suggesting paleoproductivity and water redox condition are the main controlling factors of organic enrichment and its preservation. The heterogeneity in shale lithofacies throughout the stratigraphic frame work reflects the vertical evolution of the paleo-climate and paleo-ocean environment across the Ordovician-Silurian transition. We suggest that the high primary productivity of Wufeng formation was due to the boom of diatom triggered by large scale coverage of volcanic ash before Hirnantian glaciation. Marine anoxia may have been a kill mechanism that cause the mass extinction of marine macro-organism during the glacial period. And the up sequence TOC deterioration of Longmaxi formation is likely subjected to influence of ocean bottom flow and slow recovery of marine organism after the glaciation.

Lateral trends and vertical sequences in estuarine sediments, Willapa Bay, Washington

USGS Publications Warehouse

Clifton, H. Edward; Phillips, L.

1980-01-01

Willapa Bay is a sizable estuary on the southern coast of Washington- Relatively unmodified in a geologic sense by human activity the bay provides an excellent example of modern depositional facies in an estuarine setting. Studies of these deposits indicate that consistent lateral trends exist in sediment texture and sedimentary structures. The texture changes from sandy at the mouth of the bay to muddy in its upper parts. In any part of the bay , sediment is coarsest in the channel bottoms, where lag deposits accumulate. The sediment tends to fine in an upslope direction and is finest in supratidal flat deposits of silt and clay. The nature of sedimentary structures depends on the combination of physical and biological processes and sediment textures. Bedforms exist wherever the bed is sandy. In the main tidal channels sandwaves and dunes up to 4 meters high occur. In tributary channels and at the margins of the main channel, at shallower depths and under less intense currents , the structures are generally less than a meter high. Current ripples occur in t he sandy bed of all of the tidal channels and in runoff channels cross the tidal flat. Symmetric long-crested ripples are produced by wave action over the sandy intertidal flat. Internal structures in the bay's sediment depend not only on the nature of the bedform but also on the rate of bioturbation relative to physical processes. Under fields of large sandwaves or dunes, medium- to large-scale tabular and trough crossbedding predominates. This crossbedding generally is unidirectional, reflecting the locally dominant current (ebb or flood). Ripple bedding predominates elsewhere in sandy sediment within the channels. Where sand transport is diminished, as on the floor of the upper tributary channels, bioturbation exceeds the rate of production of physical structures and bedding is destroyed. The depositional banks in such areas tend to be sites of rapid sediment accumulation and bedding in the form of interlayered sand (commonly ripple bedded) and mud persists. On intertidal flats the sediment accumulates slowly and bioturbation erases nearly all physical structures. Bedding is preserved only where deposition is locally rapid , as in topographic depressions or on the depositional banks of runoff channels, or where faunal activity is inhibited, as beneath mounds of blue-green algae. The rate of sedimentation is slower still on the supratidal flats, but the general paucity of faunal activity allows the preservation of thin alternations of fine sand , silt or clay. The lateral migration of the tidal channels produces vertical sequences in which topographically higher facies are superposed on one another. Near the mouth of the estuary the upward sequence: lag deposit — crossbedded sand — ripple or planar-bedded sand is typical. The crossbedding shows a general upward decrease in thickness and a progression from trough to tabular units. In the main tidal channel - in the central estuary and in sandy tributary channels, the typical vertical sequence resembles that near the mouth , with the exception that the sequence is capped by bioturbated sandy or muddy tide flat deposits. In the upper estuary , where muddy sediment predominates, a typical sequence shows the progression-. bioturbated lag deposit — gently dipping interlaminated sand and mud layers of the accretionary bank — bioturbated mud flat deposits — thinly laminated fine supratidal deposits.

Paleogeographic implications of an erosional remnant of Paleogene rocks southwest of the Sur-Nacimiento Fault Zone, southern Coast Ranges, California

USGS Publications Warehouse

Vedder, J.G.; McLean, H.; Stanley, R.G.; Wiley, T.J.

1991-01-01

A small tract of heretofore-unrecognized Paleogene rocks lies about 30 km northeast of Santa Maria and 1 km southwest of the Sur-Nacimiento fault zone near upper Pine Creek. This poorly exposed assemblage of rocks is less than 50 m thick, lies unconformably on regionally distributed Upper Cretaceous submarine-fan deposits, and consists of three units: fossiliferous lower Eocene mudstone, Oligocene(?) conglomerate, and basaltic andesite that has a radiometric age of 26.6 ?? 0.5 Ma. Both the sedimentary and igneous constituents in the Paleogene sequence are unlike those of known sequences on either side of the Sur-Nacimiento fault zone. The Paleogene sedimentary rocks near upper Pine Creek presumably are remnants of formerly widespread early Eocene bathyal deposits and locally distributed Oligocene(?) fluvial deposits southwest of the fault zone. The 26.6 Ma basaltic andesite, however, may not have extended much beyond its present outcrops. An episode of Oligocene(?) displacement is required by the contrast in thicknesses, depositional patterns, and paleobathymetry of the juxtaposed rock sequences. -from Authors

Biofacies expression of Upper Cretaceous sequences in the Rock Springs uplift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Y.Y.; Pflum, C.E.; Wright, R.C.

1991-03-01

The sequence-stratigraphic framework and vertical succession of depositional environments in the Upper Cretaceous section of the Rock Springs uplift is expressed in the biofacies patterns as well as in the stratal stacking patterns. Vertical trends in six biofacies parameters track affinities to marine and nonmarine environments as well as proximity to the paleoshoreline. These six parameters and their environmental significance include the relative proportion of herbaceous kerogen (land-derived), amorphous kerogen (marine), dinoflagellates (marine), bisaccate pollen (land-derived but buoyant and easily transported offshore), and the abundance and diversity of benthic foraminifera (both increase offshore). Shoaling marine environments are characterized by anmore » increasing proportion of herbaceous kerogen and decreasing proportions of amorphous kerogen, dinoflagellated, bisaccates, and the abundance and diversity of benthic foraminifera. Conversely, a deepening-upward marine sedimentary succession is characterized by an opposite trend in these parameters. A synthesis of the six biofacies parameters emphasizes the third-order cyclicity of the stratal succession as reflected in the well-developed third-order downlap surfaces and condensed sections. The biofacies trends indicate the transgressive nature of the lower Rock Springs and lower Lewis formations, and the progradational nature of the upper arts of the Baxter, Blair, and Rock Springs formations. An overall progradational (i.e., shoaling) character is exhibited in the three lower sequences (Baxter through Rock Springs) by the progressively decreasing abundance of amorphous kerogen, dinoflagellates, and foraminifera.« less

A composite foraminiferal biostratigraphic sequence for the Lower Miocene deposits in the type area of the Qom Formation, central Iran, developed by constrained optimization (CONOP)

NASA Astrophysics Data System (ADS)

Daneshian, Jahanbakhsh; Ramezani Dana, Leila; Sadler, Peter

2017-01-01

Benthic foraminifera species commonly outnumber planktic species in the type area of the Lower Miocene Qom Formation, in north central Iran, where it records the Tethyan link between the eastern Mediterranean and Indo- Pacific provinces. Because measured sections preserve very different sequences of first and last occurrences of these species, no single section provides a completely suitable baseline for correlation. To resolve this problem, we combined bioevents from three stratigraphic sections into a single composite sequence by constrained optimization (CONOP). The composite section arranges the first and last appearance events (FAD and LAD) of 242 foraminifera in an optimal order that minimizes the implied diachronism between sections. The composite stratigraphic ranges of the planktic foraminifera support a practical biozonation which reveals substantial local changes of accumulation rate during Aquitanian to Burdigalian times. Traditional biozone boundaries emerge little changed but an order of magnitude more correlations can be interpolated. The top of the section at Dobaradar is younger than previously thought and younger than sections at Dochah and Tigheh Reza-Abad. The latter two sections probably extend older into the Aquitanian than the Dobaradar section, but likely include a hiatus near the base of the Burdigalian. The bounding contacts with the Upper Red and Lower Red Formations are shown to be diachronous.

The influence of sequence of precursor films on CZTSe thin films prepared by ion-beam sputtering deposition

NASA Astrophysics Data System (ADS)

Zhao, Jun; Liang, Guangxing; Zeng, Yang; Fan, Ping; Hu, Juguang; Luo, Jingting; Zhang, Dongping

2017-02-01

The CuZnSn (CZT) precursor thin films are grown by ion-beam sputtering Cu, Zn, Sn targets with different orders and then sputtering Se target to fabricate Cu2ZnSnSe4 (CZTSe) absorber thin films on molybdenum substrates. They are annealed in the same vacuum chamber at 400 °C. The characterization methods of CZTSe thin films include X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS) in order to study the crystallographic properties, composition, surface morphology, electrical properties and so on. The results display that the CZTSe thin films got the strongest diffraction peak intensity and were with good crystalline quality and its morphology appeared smooth and compact with a sequence of Cu/Zn/Sn/Se, which reveals that the expected states for CZTSe are Cu1+, Zn2+, Sn4+, Se2+. With the good crystalline quality and close to ideal stoichiometric ratio the resistivity of the CZTSe film with the sequence of Cu/Zn/Sn/Se is lower, whose optical band gap is about 1.50 eV. Project supported by the National Natural Science Foundation of China (No. 61404086), the Basical Research Program of Shenzhen (Nos. JCYJ20150324140036866, JCYJ20150324141711581), and the Natural Science Foundation of SZU (No. 2014017).

Evaluating order in vertical successions of deltaic Holocene sediments on the Ganges-Brahmaputra-Meghna delta

NASA Astrophysics Data System (ADS)

Sincavage, R.; Goodbred, S. L., Jr.

2017-12-01

Most stratigraphic models are predicated on the presence of cyclicity or some form of order in vertical successions of strata. In spite of this a priori assumption of ordered stratigraphy, rarely are statistical metrics employed to quantify cyclicity in sedimentary packages. The presence or absence of preserved order in vertical sedimentary successions has important implications for the nature of environmental signals that are transmitted into the rock record. We interrogate the Holocene sedimentary archive of the Ganges-Brahmaputra-Meghna delta (GBMD) in an effort to explore to what extent fluvio-deltaic deposits exhibit recognizable order. Specifically, we focus on grain size data to evaluate 1.) if stratigraphic order in vertical sedimentary successions can be identified and quantified, and 2.) if there are spatial patterns of stratigraphic order across the GBMD. A runs order metric r is used to identify sequences of coarsening and fining within an extensive borehole network. Observed grain size data are shuffled enough times to generate synthetic "random" stratigraphy, and a Monte Carlo simulation generates 5000 realizations. The distribution of r values from the Monte Carlo are compared to the r metric calculated from observed data to determine how likely the observed metric could be generated by chance. The spatial distribution of order metrics indicates a relationship between areas of enhanced mass extraction and preservation of fluvial successions that scale with modern bar deposits on the Jamuna River. Similarly, probability metrics indicate that vertical successions of grain size data unlikely to have been generated by chance are more likely to be found on distal areas of the delta where 60% of the input mass has been extracted. Combining a mass balance framework with simple statistical metrics has the potential of improving predictions of the stratigraphic architecture and the preservation of ordered vs. disordered signals in the sedimentary record.

A note on coarse-grained gravity-flow deposits within proterozoic lacustrine sedimentary rocks, Transvaal sequence, South Africa

NASA Astrophysics Data System (ADS)

Eriksson, P. G.

A widely developed, thin, coarse-matrix conglomerate occurs within early Proterozoic lacustrine mudrocks in the Transvaal Sequence, South Africa. The poorly sorted tabular chert clasts, alternation of a planar clast fabric with disorientated zones, plus normal and inverse grading in the former rock type suggest deposition by density-modified grain-flow and high density turbidity currents. The lower fan-delta slope palæenvironment inferred for the conglomerate is consistent with the lacustrine interpretation for the enclosing mudrock facies. This intracratonic setting contrasts with the marine environment generally associated with density-modified grain-flow deposits.

Recent "omics" advances in Helicobacter pylori.

PubMed

Berthenet, Elvire; Sheppard, Sam; Vale, Filipa F

2016-09-01

The development of high-throughput whole genome sequencing (WGS) technologies is changing the face of microbiology, facilitating the comparison of large numbers of genomes from different lineages of a same organism. Our aim was to review the main advances on Helicobacter pylori "omics" and to understand how this is improving our knowledge of the biology, diversity and pathogenesis of H. pylori. Since the first H. pylori isolate was sequenced in 1997, 510 genomes have been deposited in the NCBI archive, providing a basis for improved understanding of the epidemiology and evolution of this important pathogen. This review focuses on works published between April 2015 and March 2016. Helicobacter "omics" is already making an impact and is a growing research field. Ultimately these advances will be translated into a routine clinical laboratory setting in order to improve public health. © 2016 John Wiley & Sons Ltd.

Early Pleistocene 40Ar/39Ar ages for Bapang Formation hominins, Central Jawa, Indonesia

PubMed Central

Larick, Roy; Ciochon, Russell L.; Zaim, Yahdi; Sudijono; Suminto; Rizal, Yan; Aziz, Fachroel; Reagan, Mark; Heizler, Matthew

2001-01-01

The Sangiran dome is the primary stratigraphic window for the Plio-Pleistocene deposits of the Solo basin of Central Jawa. The dome has yielded nearly 80 Homo erectus fossils, around 50 of which have known findspots. With a hornblende 40Ar/39Ar plateau age of 1.66 ± 0.04 mega-annum (Ma) reportedly associated with two fossils [Swisher, C.C., III, Curtis, G. H., Jacob, T., Getty, A. G., Suprijo, A. & Widiasmoro (1994) Science 263, 1118–1121), the dome offers evidence that early Homo dispersed to East Asia during the earliest Pleistocene. Unfortunately, the hornblende pumice was sampled at Jokotingkir Hill, a central locality with complex lithostratigraphic deformation and dubious specimen provenance. To address the antiquity of Sangiran H. erectus more systematically, we investigate the sedimentary framework and hornblende 40Ar/39Ar age for volcanic deposits in the southeast quadrant of the dome. In this sector, Bapang (Kabuh) sediments have their largest exposure, least deformation, and most complete tephrostratigraphy. At five locations, we identify a sequence of sedimentary cycles in which H. erectus fossils are associated with epiclastic pumice. From sampled pumice, eight hornblende separates produced 40Ar/39Ar plateau ages ranging from 1.51 ± 0.08 Ma at the Bapang/Sangiran Formation contact, to 1.02 ± 0.06 Ma, at a point above the hominin-bearing sequence. The chronological sequence of 40Ar/39Ar ages follows stratigraphic order across the southeast quadrant. An intermediate level yielding four nearly complete crania has an age of about 1.25 Ma. PMID:11309488

Microbial Composition of Near-Boiling Silica-Depositing Thermal Springs throughout Yellowstone National Park

PubMed Central

Blank, Carrine E.; Cady, Sherry L.; Pace, Norman R.

2002-01-01

The extent of hyperthermophilic microbial diversity associated with siliceous sinter (geyserite) was characterized in seven near-boiling silica-depositing springs throughout Yellowstone National Park using environmental PCR amplification of small-subunit rRNA genes (SSU rDNA), large-subunit rDNA, and the internal transcribed spacer (ITS). We found that Thermocrinis ruber, a member of the order Aquificales, is ubiquitous, an indication that primary production in these springs is driven by hydrogen oxidation. Several other lineages with no known close relatives were identified that branch among the hyperthermophilic bacteria. Although they all branch deep in the bacterial tree, the precise phylogenetic placement of many of these lineages is unresolved at this time. While some springs contained a fair amount of phylogenetic diversity, others did not. Within the same spring, communities in the subaqueous environment were not appreciably different than those in the splash zone at the edge of the pool, although a greater number of phylotypes was found along the pool's edge. Also, microbial community composition appeared to have little correlation with the type of sinter morphology. The number of cell morphotypes identified by fluorescence in situ hybridization and scanning electron microscopy was greater than the number of phylotypes in SSU clone libraries. Despite little variation in Thermocrinis ruber SSU sequences, abundant variation was found in the hypervariable ITS region. The distribution of ITS sequence types appeared to be correlated with distinct morphotypes of Thermocrinis ruber in different pools. Therefore, species- or subspecies-level divergences are present but not detectable in highly conserved SSU sequences. PMID:12324363

Early Pleistocene 40Ar/39Ar ages for Bapang Formation hominins, Central Jawa, Indonesia.

PubMed

Larick, R; Ciochon, R L; Zaim, Y; Sudijono; Suminto; Rizal, Y; Aziz, F; Reagan, M; Heizler, M

2001-04-24

The Sangiran dome is the primary stratigraphic window for the Plio-Pleistocene deposits of the Solo basin of Central Jawa. The dome has yielded nearly 80 Homo erectus fossils, around 50 of which have known findspots. With a hornblende (40)Ar/(39)Ar plateau age of 1.66 +/- 0.04 mega-annum (Ma) reportedly associated with two fossils [Swisher, C.C., III, Curtis, G. H., Jacob, T., Getty, A. G., Suprijo, A. & Widiasmoro (1994) Science 263, 1118-1121), the dome offers evidence that early Homo dispersed to East Asia during the earliest Pleistocene. Unfortunately, the hornblende pumice was sampled at Jokotingkir Hill, a central locality with complex lithostratigraphic deformation and dubious specimen provenance. To address the antiquity of Sangiran H. erectus more systematically, we investigate the sedimentary framework and hornblende (40)Ar/(39)Ar age for volcanic deposits in the southeast quadrant of the dome. In this sector, Bapang (Kabuh) sediments have their largest exposure, least deformation, and most complete tephrostratigraphy. At five locations, we identify a sequence of sedimentary cycles in which H. erectus fossils are associated with epiclastic pumice. From sampled pumice, eight hornblende separates produced (40)Ar/(39)Ar plateau ages ranging from 1.51 +/- 0.08 Ma at the Bapang/Sangiran Formation contact, to 1.02 +/- 0.06 Ma, at a point above the hominin-bearing sequence. The chronological sequence of (40)Ar/(39)Ar ages follows stratigraphic order across the southeast quadrant. An intermediate level yielding four nearly complete crania has an age of about 1.25 Ma.

The Late Holocene Stratigraphy of an Inlet-Dominated Barrier Island, Pea Island, North Carolina.

NASA Astrophysics Data System (ADS)

Smith, C. G.; Ames, D.; Corbett, D. R.; Culver, S.; Mallinson, D.; Riggs, S. R.; Vance, D.

2002-12-01

Sedimentological, foraminiferal, geochemical, and geophysical data sets as well as aerial photographs have been used to investigate the natural processes (inlet dynamics, ocean/estuarine washover, and sea-level change) responsible for the late Holocene units preserved in the barrier island subsurface at Pea Island National Wildlife Refuge. Historic nautical charts indicate that three inlets characterized Pea Island between early European exploration (1590) and the late 19th century; aerial photographs show New Inlet open in 1932 and 1940. Vibracores (up to 5.5 m) collected along three transects across Pea Island extend our knowledge of the geological evolution of this region to pre-historic times. The section in the longest core (PI01S6) consists of four fining-upwards depositional sequences. The basal unit of each sequence is a bedded, medium to fine, clean quartz sand with increasing concentrations of organic matter (3-4 % detrital and 5-7 % in situ Spartina alterniflora roots) or irregular mud clasts (2-5 cm) to spherical mud balls (1-2 cm) up core. The clean sand units have so far proven to be barren of foraminifera except for a shelly unit at ca. 220 cm below MSL. The foraminiferal assemblage in this unit is of open shelf character (Elphidium excavatum, Hanzawaia strattoni, and Buccella inusitata). A 14C age on a disarticulated Chione cancellata valve from this unit is cal. 930+/-60 BP. The sand grades into a gray, tight mud in the first two sequences and into an inter-laminated mud and in situ peat in the third sequence. The peat contains leaf fragments and rhizomes of the marsh plants Juncus roemarianus, Spartina cynosuroides, and/or Phragmites spp. The peat and muddy sand units contain marsh foraminifera (Trochammina spp., Miliammina fusca, Arenoparrella mexicana), which are also found in modern marsh deposits. A peat sample from the third fining upward sequence (the only one to grade into a true peat) has a 14C age of cal. 395+/-35 BP, cal. 295+/-35 BP, or cal 180+/-40 BP. The four fining-upwards sequences have sharp erosional basal contacts. These deposits appear to reflect back-barrier processes including sequential deposition of flood-tide delta sands and/or sound sands adjacent to marshes. The shelly sands, containing open shelf foraminiferal assemblages, represent oceanic overwash, inlet deposits, or open embayment sands deposited behind a laterally extensive breach in the barrier island. The sequences are capped by the deposits of modern environments that include algal flats, tidal creeks, high and low marshes, back-barrier berms, overwash fans, and aeolian dunes. Several of the modern environments became covered with marsh vegetation after the construction of barrier dune ridges in the late 1930?s.

Sedimentary record of erg migration

NASA Astrophysics Data System (ADS)

Porter, M. L.

1986-06-01

The sedimentary record of erg (eolian sand sea) migration consists of an idealized threefold division of sand-sea facies sequences. The basal division, here termed the fore-erg, is composed of a hierarchy of eolian sand bodies contained within sediments of the flanking depositional environment. These sand bodies consist of eolian strata deposited by small dune complexes, zibars, and sand sheets. The fore-erg represents the downwind, leading edge of the erg and records the onset of eolian sedimentation. Basin subsidence coupled with erg migration places the medial division, termed the central erg, over the fore-erg strata. The central erg, represented by a thick accumulation of large-scale, cross-stratified sandstone, is the product of large draa complexes. Eolian influence on regional sedimentation patterns is greatest in the central erg, and most of the sand transported and deposited in the erg is contained within this region. Reduction in sand supply and continued erg migration will cover the central-erg deposits with a veneer of back-erg deposits. This upper division of the erg facies sequence resembles closely the fore-erg region. Similar types of eolian strata are present and organized in sand bodies encased in sediments of the upwind flanking depositional environment(s). Back-erg deposits may be thin due to limited eolian influence on sedimentation or incomplete erg migration, or they may be completely absent because of great susceptibility to postdepositional erosion. Tectonic, climatic, and eustatic influences on sand-sea deposition will produce distinctive variations or modifications of the idealized erg facies sequence. The resulting variants in the sedimentary record of erg migration are illustrated with ancient examples from western North America, Europe, southern Africa, and South America.

Depositional environments and paleogeography of the Upper Miocene Wassuk Group, west-central Nevada

USGS Publications Warehouse

Golia, R.T.; Stewart, John H.

1984-01-01

Fluvial and lacustrine deposits of the Miocene Wassuk Group, exposed in Coal Valley, west-central Nevada, are divided into five lithofacies: (1) diatomite, claystone, siltstone, and carbonaceous siltstone deposited in a lake with paludal conditions at the margin; (2) upward-coarsening sequences of sandstone deposited on a delta and fan-delta; (3) channel-form sandstone deposited on a distal braided alluvial plain; (4) clast-supported conglomerate deposited on a proxial braided alluvial plain or distal alluvial fan; and (5) matrix-supported conglomerate deposited on a distal to middle alluvial fan. Petrographic analysis records an upsection change from a predominantly andesitic to a predominantly plutonic provenance. This change, combined with the overall upward-coarsening of the Wassuk Group and the great thickness (2400 m) of the sequence, suggests active uplift and rapid subsidence during deposition of the group. Facies relationships and paleocurrent directions indicate source areas to the south, southeast and west of Coal Valley. The Miocene Wassuk Group was deposited in an intra-arc basin with penecontemporaneous volcanism and tectonic activity. Syndepositional faulting at the southern margin of Coal Valley between 13 and 11 m.y. ago suggests an early episode of northeast-southwest extension prior to the onset of east-west basin and range extension. ?? 1984.

Seismic analysis of clinoform depositional sequences and shelf-margin trajectories in Lower Cretaceous (Albian) strata, Alaska North Slope

USGS Publications Warehouse

Houseknecht, D.W.; Bird, K.J.; Schenk, C.J.

2009-01-01

Lower Cretaceous strata beneath the Alaska North Slope include clinoform depositional sequences that filled the western Colville foreland basin and overstepped the Beaufort rift shoulder. Analysis of Albian clinoform sequences with two-dimensional (2D) seismic data resulted in the recognition of seismic facies inferred to represent lowstand, transgressive and highstand systems tracts. These are stacked to produce shelf-margin trajectories that appear in low-resolution seismic data to alternate between aggradational and progradational. Higher-resolution seismic data reveal shelf-margin trajectories that are more complex, particularly in net-aggradational areas, where three patterns commonly are observed: (1) a negative (downward) step across the sequence boundary followed by mostly aggradation in the lowstand systems tract (LST), (2) a positive (upward) step across the sequence boundary followed by mostly progradation in the LST and (3) an upward backstep across a mass-failure d??collement. These different shelf-margin trajectories are interpreted as (1) fall of relative sea level below the shelf edge, (2) fall of relative sea level to above the shelf edge and (3) mass-failure removal of shelf-margin sediment. Lowstand shelf margins mapped using these criteria are oriented north-south in the foreland basin, indicating longitudinal filling from west to east. The shelf margins turn westward in the north, where the clinoform depositional system overstepped the rift shoulder, and turn eastward in the south, suggesting progradation of depositional systems from the ancestral Brooks Range into the foredeep. Lowstand shelf-margin orientations are consistently perpendicular to clinoform-foreset-dip directions. Although the Albian clinoform sequences of the Alaska North Slope are generally similar in stratal geometry to clinoform sequences elsewhere, they are significantly thicker. Clinoform-sequence thickness ranges from 600-1000 m in the north to 1700-2000 m in the south, reflecting increased accommodation from the rift shoulder into the foredeep. The unusually thick clinoform sequences suggest significant subsidence followed by rapid sediment influx. No claim to original US government works. Journal Compilation ?? Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists.

Significance of a near-source tephra-stratigraphic sequence to the eruptive history of Hayes Volcano, south-central Alaska

USGS Publications Warehouse

Wallace, Kristi; Coombs, Michelle L.; Hayden, Leslie A.; Waythomas, Christopher F.

2014-01-01

Bluffs along the Hayes River valley, 31 km northeast and 40 km downstream from Hayes Volcano, reveal volcanic deposits that shed new light on its eruptive history. Three thick (>10 cm) and five thin (<10 cm) tephra-fall deposits are dacitic in whole rock composition and contain high proportions of amphibole to pyroxene and minor biotite and broadly correlate to Hayes tephra set H defined by earlier investigators. Two basal ages for the tephra-fall sequence of 3,690±30 and 3,750±30 14C yr B.P. are also consistent with the Hayes tephra set H timeframe. Distinguishing among Hayes tephra set H units is critical because the set is an important time-stratigraphic marker in south-central Alaska and this section provides a new reference section for Hayes tephra set H. Analysis of Fe-Ti oxide grains in the tephras shows promise for identifying individual Hayes deposits. Beneath the dacitic tephra sequence lies an older, poorly sorted tephra (tephra A) that contains dacite and rhyolite lapilli and whose basal age is 4,450±30 14C yr B.P. Immediately below the tephra-fall sequence (Unit III) lies a series of mass-flow deposits that are rich in rhyodacitic clasts (Unit II). Below Unit II and possibly coeval with it, is a 20–30 m thick pumiceous pyroclastic-flow deposit (Unit I) that extends to the valley floor. Here informally named the Hayes River ignimbrite, this deposit contains pumice clasts of rhyolite with quartz, sanidine, plagioclase, and biotite phenocrysts, an assemblage that is unique among known Quaternary volcanic products of Hayes and other Alaskan volcanoes. Units I, II, and tephra A of Unit III represent at least two previously unrecognized eruptions of Hayes Volcano that occurred prior to ~3,700 yr B.P. No compositionally equivalent distal tephra deposits correlative with Hayes Volcano rhyodacites or rhyolites have yet been identified, perhaps indicating that some of these deposits are pre-Holocene, and were largely removed by glacial ice during the last ice age. More field and analytical work is needed to further refine the eruptive history of Hayes Volcano.

Sequence-Stratigraphic Analysis of the Regional Observation Monitoring Program (ROMP) 29A Test Corehole and Its Relation to Carbonate Porosity and Regional Transmissivity in the Floridan Aquifer System, Highlands County, Florida

USGS Publications Warehouse

Ward, W. C.; Cunningham, K.J.; Renken, R.A.; Wacker, M.A.; Carlson, J.I.

2003-01-01

An analysis was made to describe and interpret the lithology of a part of the Upper Floridan aquifer penetrated by the Regional Observation Monitoring Program (ROMP) 29A test corehole in Highlands County, Florida. This information was integrated into a one-dimensional hydrostratigraphic model that delineates candidate flow zones and confining units in the context of sequence stratigraphy. Results from this test corehole will serve as a starting point to build a robust three-dimensional sequence-stratigraphic framework of the Floridan aquifer system. The ROMP 29A test corehole penetrated the Avon Park Formation, Ocala Limestone, Suwannee Limestone, and Hawthorn Group of middle Eocene to Pliocene age. The part of the Avon Park Formation penetrated in the ROMP 29A test corehole contains two composite depositional sequences. A transgressive systems tract and a highstand systems tract were interpreted for the upper composite sequence; however, only a highstand systems tract was interpreted for the lower composite sequence of the deeper Avon Park stratigraphic section. The composite depositional sequences are composed of at least five high-frequency depositional sequences. These sequences contain high-frequency cycle sets that are an amalgamation of vertically stacked high-frequency cycles. Three types of high-frequency cycles have been identified in the Avon Park Formation: peritidal, shallow subtidal, and deeper subtidal high-frequency cycles. The vertical distribution of carbonate-rock diffuse flow zones within the Avon Park Formation is heterogeneous. Porous vuggy intervals are less than 10 feet, and most are much thinner. The volumetric arrangement of the diffuse flow zones shows that most occur in the highstand systems tract of the lower composite sequence of the Avon Park Formation as compared to the upper composite sequence, which contains both a backstepping transgressive systems tract and a prograding highstand systems tract. Although the porous and permeable layers are not thick, some intervals may exhibit lateral continuity because of their deposition on a broad low-relief ramp. A thick interval of thin vuggy zones and open faults forms thin conduit flow zones mixed with relatively thicker carbonate-rock diffuse flow zones between a depth of 1,070 and 1,244 feet below land surface (bottom of the test corehole). This interval is the most transmissive part of the Avon Park Formation penetrated in the ROMP 29A test corehole and is included in the highstand systems tract of the lower composite sequence. The Ocala Limestone is considered to be a semiconfining unit and contains three depositional sequences penetrated by the ROMP 29A test corehole. Deposited within deeper subtidal depositional cycles, no zones of enhanced porosity and permeability are expected in the Ocala Limestone. A thin erosional remnant of the shallow marine Suwannee Limestone overlies the Ocala Limestone, and permeability seems to be comparatively low because moldic porosity is poorly connected. Rocks that comprise the lower Hawthorn Group, Suwannee Limestone, and Ocala Limestone form a permeable upper zone of the Upper Floridan aquifer, and rocks of the lower Ocala Limestone and Avon Park Formation form a permeable lower zone of the Upper Floridan aquifer. On the basis of a preliminary analysis of transmissivity estimates for wells located north of Lake Okeechobee, spatial relations among groups of relatively high and low transmissivity values within the upper zone are evident. Upper zone transmissivity is generally less than 10,000 feet squared per day in areas located south of a line that extends through Charlotte, Sarasota, DeSoto, Highlands, Polk, Osceola, Okeechobee, and St. Lucie Counties. Transmissivity patterns within the lower zone of the Avon Park Formation cannot be regionally assessed because insufficient data over a wide areal extent have not been compiled.

Hierarchal Genetic Stratigraphy: A Framework for Paleoceanography

NASA Astrophysics Data System (ADS)

Busch, R. M.; West, R. R.

1987-04-01

A detailed, genetic stratigraphic framework for paleoceanographic studies can be derived by describing, correlating, interpreting, and predicting stratigraphic sequences relative to a hierarchy of their constituent time-stratigraphic transgressive-regressive units ("T-R units"). T-R unit hierarchies are defined and correlated using lithostratigraphic and paleoecologic data, but correlations can be enhanced or "checked" (tested to confirm or deny) with objective biostratigraphic, magnetostratigraphic, or chemostratigraphic data. Such chronostratigraphies can then be bracketed by radiometric ages, so that average periodicities for T-R units can be calculated and a hierarchal geochronology derived. T-R units are inferred to be the net depositional result of eustatic cycles of sea level change and can be differentiated from autocyclic deepening-shallowing units because the latter are noncorrelative intrabasinally. Boundaries between T-R units are conformable or unconformable "genetic surfaces" of two types: transgressive surfaces and "climate change surfaces". The latter are useful for correlating minor transgressive phases through nonmarine intervals, thereby deriving information linking paleoclimatic and paleoceanographic processes. Permo-Carboniferous sequences can be analyzed relative to a hierarchy of six scales of genetic T-R units having periodicities of 225-300 m.y. (first order), 20-90 m.y. (second order), 7-13 m.y. (third-order), 0.6-3.6 m.y. (fourth order), 300-500 × 10³ years (fifth order), and 50-130 × 10³ years or less (sixth-order). Paleogeographic maps for the time of maximum transgression ("transgressive apex") of successive fifth-order T-R units (5-25 m thick) in the Glenshaw Formation (Upper Pennsylvanian, Northern Appalachian Basin) delineate delta lobes, embayments, islands, and linear seaways. Relative extent of marine inundation on the fifth-order maps was used to delineate fourth-order T-R units, and the fourth-order T-R units constitute the transgressive half of a third-order T-R unit. This third-, fourth-, and fifth-order hierarchy is correlated more than 1200 km (750 miles) to the Western Interior "Basin," and is confirmed with limited objective biostratigraphy.

The Olympic Dam copper-uranium-gold deposit, Roxby Downs, South Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, D.E.; Hudson, G.R.T.

1983-08-01

The Olympic Dam copper-uranium-gold deposit appears to be a new type of strata-bound sediment-hosted ore deposit. It is located 650 km north-northwest of Adelaide in South Australia and was discovered in 1975. It has an areal extent exceeding 20 km/sup 2/ with vertical thicknesses of mineralization up to 350 m. The deposit is estimated to contain in excess of 2,000 million metric tons of mineralized material with an average grade of 1.6 percent copper, 0.06 percent uranium oxide, and 0.6 g/metric ton gold. The deposit occurs in the basement beneath 350 m of unmineralized, flat-lying Adelaidean (late Proterozoic) to Cambrianmore » sediments in the Stuart shelf region of South Australia. The host rocks of the deposit are unmetamorphosed and are probably younger than 1,580 m.y. The deposit is spatially related to coincident gravity and magnetic anomalies and the intersection of west-northwest- and north-northwest-trending lineaments. The Proterozoic sediments comprising the local basement sequence are predominantly sedimentary breccias ranging from matrix-poor granite breccias to matrix-rich polymict breccias containing clasts of a variety of rock types. This sequence is over 1 km thick and has been divided into two main units--the Olympic Dam Formation and the Greenfield Formation. The Olympic Dam Formation has five members, three of which are matrix rich. The Greenfield Formation has three members, the lower two being very hematite rich while the upper has a significant volcanic component. Pervasive hematite, chlorite, and sericite alteration of varying intensity affects all the basement sequence.« less

Glacial origin for cave rhythmite during MIS 5d-c in a glaciokarst landscape, Picos de Europa (Spain)

NASA Astrophysics Data System (ADS)

Ballesteros, Daniel; Jiménez-Sánchez, Montserrat; Giralt, Santiago; DeFelipe, Irene; García-Sansegundo, Joaquín

2017-06-01

Laminated slackwater deposits have been identified in many karst caves related to fluvial and lacustrine sedimentation. However, sedimentological evidence rarely supports a glacial origin for these deposits, which was proposed by previous studies. The Torca La Texa shaft is located in a glaciokarst area that comprises numerous slackwater-type deposits, piled up in fining-upward sequences. A basal sandy erosive layer and millimeter-sized laminated rhythmite with interbedded flowstone characterize these sequences. Fining-upward layers of carbonate silt, clay, and minor quartz sand deposited in flooded conduits define the rhythmite lamination. The presence of allochthonous minerals indicates that the rhythmite sediment comes from the glacial erosion of nearby carbonate mountains. Two 234U/230Th radiometric ages dated the rhythmite deposits around 109 and 95 ka, coinciding with relative cold periods included in the MIS 5d-c. These cold periods were marked by a high annual seasonality, immediately after the glacial local maximum extension, in agreement with a varve-type deposit. The combination of these sedimentological mineralogical, geomorphological and paleoclimate information indicates that the rhythmite should be introduced into the studied cave during the summer melting of the glaciers, which produced the recharge of the karst aquifer, triggering cave floods. In addition, punctual glacier collapses would also have their imprint in the slackwater sequences with thicker, coarser and erosive sand deposits and the spring blocking by glaciers may have promoted floods inside the cave. Therefore, the studied rhythmite can be interpreted as glacial varves decanted during the relatively cold climate conditions.

Constraining Depositional Slope From Sedimentary Structures in Sandy Braided Streams

NASA Astrophysics Data System (ADS)

Lynds, R. M.; Mohrig, D.; Heller, P. L.

2003-12-01

Determination of paleoslopes in ancient fluvial systems has potentially broad application to quantitatively constraining the history of tectonics and paleoclimate in continental sequences. Our method for calculating paleoslopes for sandy braided streams is based upon a simple physical model that establishes depositional skin-frictional shear stresses from assemblages of sedimentary structures and their associated grain size distributions. The addition of a skin-frictional shear stress, with a geometrically determined form-drag shear stress results in a total boundary shear stress which is directly related to water-surface slope averaged over an appropriate spatial scale. In order to apply this model to ancient fluvial systems, it is necessary to measure the following: coarsest suspended sediment size, finest grain size carried in bed load, flow depth, dune height, and dune length. In the rock record, suspended load and bed load can be accurately assessed by well-preserved suspended load deposits ("low-energy" ripples) and bed load deposits (dune foresets). This model predicts an average slope for the North Loup River near Taylor, Nebraska (modern case study) of 2.7 x 10-3. The measured reach-averaged water surface slope for the same reach of the river is 1.37 x 10-3. We suggest that it is possible to calculate the depositional slope of a sandy fluvial system by a factor of approximately two. Additionally, preliminary application of this model to the Lower Jurassic Kayenta Formation throughout the Colorado Plateau provides a promising and consistent evaluation of paleoslope in an ancient and well-preserved, sandy braided stream deposit.

Sedimentary Basin Structure of the Hadar Formation's Lacustrine-Dominated Depocenter (Ledi-Geraru, Afar, Ethiopia) and its Relevance for Investigating Hominin Paleoenvironments

NASA Astrophysics Data System (ADS)

Dimaggio, E. N.; Campisano, C. J.; Arrowsmith, J. R.; Dupont-Nivet, G.; Johnson, R. A.; Warren, M. B.

2008-12-01

Sedimentary sequences preserved in East African rift basins record the long-term response of past depositional environments to climatic and tectonic forcing. Motivations for recent field investigations at the Ledi-Geraru site, part of the greater Hadar sedimentary basin in the Afar region of Ethiopia, stem from a need to characterize local basin structure and expand and refine interpretations of the complex mid-late Pliocene history of local and regional-scale landscape change during a time of critical importance for understanding hominin evolution. Detailed geologic mapping (1:7,000), measured stratigraphic sections, and seismic reflection surveys provide the datasets necessary for basin evaluation. The Ledi-Geraru sedimentary sequence (>250m thick) exposes nearly the entirety of the hominin-bearing Hadar Formation of west- central Afar. Both primary unmodified lake deposits and intervals modified by subsequent subaerial exposure and pedogenesis are well-exposed. The lacustrine-dominated signature is indicated by the prevalence of laminated silty clays that contain leaf impressions, fish scales, and gastropod shells, undisturbed laminated diatomite and clays, and pedogenically modified diatomaceous silts. The sequence is generally flat lying, with low bedding dips ranging from 0-2° NNW to <1° NNE and minor NNW trending faults with <5 m vertical offset. Whereas coeval fluvio-lacustrine sediments associated with hominin and archaeological sites west of Ledi-Geraru (e.g., Hadar and Gona) are marked by comparatively slow and episodic sedimentation, sedimentation rates in the Ledi-Geraru sequence are extremely high and consistent, on the order of ~0.9-1.0mm/yr. Laterally extensive tephra marker beds and paleomagnetic records provide excellent age control for sedimentation rate estimates and correlation to nearby fossil-rich sequences. As the Hadar basin sediments preserve a rich paleoanthropologic and archaeological record, this work provides the geologic framework necessary for a proposed (2011) continental drilling effort to obtain a near-continuous, ultra-high resolution terrestrial record of past climate variability from multiple paleo-lake basins in East Africa, including the Ledi-Geraru. A seismic reflection survey was completed there in spring 2008, below the planned drilling site. Gently east-dipping coherent reflections interpreted to be from the Ledi-Geraru sedimentary sequence are imaged in the seismic data to at least 0.2 to 0.3 s (two-way travel time). Preliminary average velocities of about 2000 m/s suggest a sequence thickness of 200-300 m. Furthermore, there is no indication of large-offset faults or of buried basalt ridges that would disrupt or reduce the stratigraphic column available for coring. The anticipated cores from Ledi-Geraru should yield a high-resolution chronostratigraphic framework and paleoenvironmental record from >3.5 to 2.9Ma. Combined geologic and seismic evaluations of depositional sequences are central for evaluating the geometry, tectonic evolution, and stratigraphic history of basins and facilitate interpretations of the space-time progression of evolving paleosurfaces.

Sedimentary facies and Holocene progradation rates of the Changjiang (Yangtze) delta, China

NASA Astrophysics Data System (ADS)

Hori, Kazuaki; Saito, Yoshiki; Zhao, Quanhong; Cheng, Xinrong; Wang, Pinxian; Sato, Yoshio; Li, Congxian

2001-11-01

The Changjiang (Yangtze) River, one of the largest rivers in the world, has formed a broad tide-dominated delta at its mouth during the Holocene sea-level highstand. Three boreholes (CM97, JS98, and HQ98) were obtained from the Changjiang delta plain in 1997-1998 to clarify the characteristics of tide-dominated delta sediments and architecture. Based on sediment composition and texture, and faunal content, core sediments were divided into six depositional units. In ascending order, they were interpreted as tidal sand ridge, prodelta, delta-front, subtidal to lower intertidal flat, upper intertidal flat, and surface soil deposits. The deltaic sequence from the prodelta deposits to the delta front deposits showed an upward-coarsening succession, overlain by an upward-fining succession from the uppermost part of the delta front deposits to the surface soil. Thinly interlaminated to thinly interbedded sand and mud (sand-mud couplets), and bidirectional cross laminations in these deposits show that tide is the key factor affecting the formation of Changjiang deltaic facies. Sediment facies and their succession combined with AMS 14C dating revealed that isochron lines cross unit boundaries clearly, and delta progradation has occurred since about 6000 to 7000 years BP, when the rising sea level neared or reached its present position. The average progradation rate of the delta front was approximately 50 km/kyear over the last 5000 years. The progradation rate, however, increased abruptly ca. 2000 years BP, going from 38 to 80 km/kyear. The possible causes for this active progradation could have been an increase in sediment production in the drainage basin due to widespread human interference and/or decrease in deposition in the middle reaches related to the channel stability caused by human activity and climatic cooling after the mid-Holocene.

Sequence stratigraphic applications to deep-water exploration in the Makassar Strait, offshore East Kalimantan, Indonesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malacek, S.J.; Reaves, C.M.; Atmadja, W.S.

1994-07-01

A sequence stratigraphic study was conducted to help evaluate the exploration potential of the Makassar PSC, offshore East Kalimantan, Indonesia. The PSC is on the present-day slope in water depths of 500-3000 ft and borders the large oil and gas fields of the Mahakam delta. The study provided important insights on reservoir distribution, trapping style, and seismic hydrocarbon indicators. Lowstand deposition on a slope modified by growth faulting and shale diapirism controlled reservoir distribution within the prospective late Miocene section. Three major lowstand intervals can be seismically defined and tied to deep-water sands in nearby wells where log character andmore » biostratigraphic data support the seismic system tract interpretation. The three intervals appear to correlate with third-order global lowstand events and are consistent with existing sequence stratigraphic schemes for the shelf and upper slope in the Makassar area. Seismic mapping delineated lowstand features, including incised valleys and intraslope to basin-floor thicks. Regional information on positions of middle-late Miocene delta lobes and shelf edges, helped complete the picture for sand sources, transport routes, and depocenters.« less

Coupling molecules and morphology to discover new clades of ciliates.

NASA Astrophysics Data System (ADS)

Grattepanche, J. D.; Maurer-Alcalá, X. X.; Tucker, S. J.; McManus, G. B.; Katz, L. A.

2016-02-01

In a previous study using high-throughput sequencing (Grattepanche et al submitted, oral presentation?), we observe the presence of two clades of spirotrich ciliates mainly present in marine deep-water along the New England coast. These clades, clusters X1 and X2, are characterized by several deletions in their SSU-rDNA and have been observed elsewhere as both identical and similar sequences have been deposited on GenBank from other environmental studies, but lack morphological description. In order to link molecules (SSU-rDNA sequence) to their morphology, we sample below the photic zone (between 60 to 400m of depth) in the New England coast (Northeast Atlantic) in a transect crossing the continental shelf. We designed an oligonucleotide probe specific for choreotrich and oligotrich ciliates and another specific to clusters X1 and X2 to describe these clades through a combination of Fluorescence In Situ Hybridization (FISH) and light microscopy. Our aim is to increase our knowledge on the morphology of these `unknown' clades of ciliates, which will allow for future ecological studies.

Sedimentology and geochemistry of lacustrine sequences of the upper Pleistocene and holocene in intertropical area (Lake Magadi and Green crater lake): paleoclimatic implications

NASA Astrophysics Data System (ADS)

Damnati, B.

1993-05-01

Sedimentological and geochemical analyses have been carried out on lacustrine deposits of East Africa, at Lake Magadi (2°S, 36°E, Kenya) and at Green Crater Lake (0°S, 36°E, Kenya), to determine the parameters controlling climatic and environmental dynamics during late Pleistocene and Holocene. These sedimentary sequences were collected with a stationary piston corer. At Lake Magadi (Fig. 1), sedimentary and geochemical control show three phases of lake level variation which corresponds to climatic change occurring during the last 40 thousand years. These phases were defined by three lithostratigraphic units. Laminated deposits of Lake Magadi were formed during a wet period. Analysis of these laminae define two microfacies: a dark lamina, characterised by lacustrine organic matter and a light lamina enriched in detritus, carbonates (CaCO 3) and magadiite (NaSi 7O 13(OH) 3, 3H 2O). The formation and preservation of each couplet was favoured by climatic contrast, lake stratification and various origin of the sediments (autochthon and allochthon) in the drainage basin. Therefore a relative chronology can be derived from laminae counting and the duration of deposition of each couplet. Spectral analysis applied on variation of the laminae thickness, shows the existence of three main periods, 4-7 years, 8-14 years and 18-30 years, respectively (Fig. 2). These cyclicites of the lacustrine environment precise former determinations established on more recent lacustrine sequences from East Africa. They are related to the global climatic cycle (quasi-biannual oscillations, El Nino Southern Oscillations and the sun spot cycles). At Green Crater Lake, the study of the sedimentary sequence was completed by physico-chemical analysis of the waters and interface sediments which demonstrate the carbonate, sodium, bicarbonate composition and the thermal and chemical stratification of the modern lake. The sedimentary sequence is characterized by volcanic deposits overlain by physico-chemical analysis of the lake waters and interface sediments which demonstrate the carbonate, sodium, bicarbonate composition and the thermal and chemical stratification of the modern lake. The sedimentary sequence is characterized by volcanic deposits overlain by silt and clays deposited before 7400 years B.P., followed by loweing of the lake level at 3000 years B. P. Results from lake Magadi document the occurrence of a wet period starting at about 12,000 years B. P. The methodology applied on modern Green Crater lake provides base of interpretative models for other Holocene sequence lacustrine systems of intertropical zones.

Basin evolution of the Paleoproterozoic Karelian Supergroup of the Fennoscandian (Baltic) Shield

NASA Astrophysics Data System (ADS)

Ojakangas, Richard W.; Marmo, Jukka S.; Heiskanen, Kim I.

2001-06-01

The peneplaned Archean craton of the Fennoscandian Shield served as a platform upon which a continental margin assemblage, the Karelian Supergroup, was deposited between ˜2.45 and ˜1.9 Ga. Major subaerial unconformities separate five sedimentary-volcanic groups of the supergroup — the Sumian, Sariolian, Jatulian (Lower and Upper), Ludicovian, and Kalevian. Second-order depositional sequences are implied. Early extension (˜2.45 Ga) resulted in localized rifts that were likely areas of later subsidence as well; they received thicker accumulations of sediments and volcanic rocks than did the adjacent platform. It is in these rifts and perhaps other downwarped areas that the sediments that were once more widespread were preserved, leading to interpretations of separate depositional basins by some workers. Seas transgressed onto the craton at least three times — in Sariolian time as evidenced by interpreted glaciomarine deposits, in Jatulian time as evidenced by widespread orthoquartzites (including tidalites) and stromatolitic carbonates, and in Ludicovian time as evidenced by organic-rich shales and turbidites. The tectonic-magmatic history is complex. Three episodes of mafic volcanism were widespread at 2.45, 2.2, and 2.1 Ga. Island arcs formed to the south of the craton and collided at ˜1.9-1.85 Ga (the Svecofennian orogeny). This collision resulted in northeastward thrusting (e.g. the Outokumpu nappe) and folding and metamorphism of the Karelian Supergroup. The primary paleoclimatic indicators are (1) glaciogenic rocks near the base of the Paleoproterozoic succession indicating ice-house conditions; (2) remnants of a major paleosol on the glaciogenic rocks, indicative of deep weathering under greenhouse conditions (subtropical or tropical?); and (3) carbonate pseudomorphs after evaporite minerals in stromatolitic dolomites, perhaps indicative of aridity. Similarities in magmatism, tectonics, sedimentary rock types and sequences, and paleoclimatic indicators have led to hypotheses that the Fennoscandian Shield and North America may have been part of the same supercontinent during Neoarchean and Paleoproterozoic time.

Geology, ore facies and sulfur isotopes geochemistry of the Nudeh Besshi-type volcanogenic massive sulfide deposit, southwest Sabzevar basin, Iran

NASA Astrophysics Data System (ADS)

Maghfouri, Sajjad; Rastad, Ebrahim; Mousivand, Fardin; Lin, Ye; Zaw, Khin

2016-08-01

The southwest Sabzevar basin is placed in the southwestern part of a crustal domain known as the Sabzevar zone, at the north of Central Iranian microcontinent. This basin hosts abundant mineral deposits; particularly of the Mn exhalative and Cu-Zn volcanogenic massive sulfide (VMS) types. The evolution of this basin is governed by the Neo-tethys oceanic crust subduction beneath the Central Iranian microcontinent and by the resulting continental arc (Sanandaj-Sirjan) and back-arc (Sabzevar-Naien). This evolution followed two major sequences: (I) Lower Late Cretaceous Volcano-Sedimentary Sequence (LLCVSS), which is indicated by fine-grained siliciclastic sediments, gray basic coarse-grained different pyroclastic rocks and bimodal volcanism. During this stage, tuff-hosted stratiform, exhalative Mn deposits (Nudeh, Benesbourd, Ferizy and Goft), oxide Cu deposits (Garab and Ferizy) and Cu-Zn VMS (Nudeh, Chun and Lala) deposits formed. (II) Upper Late Cretaceous Sedimentary Dominated Sequence (ULCSS), including pelagic limestone, marly tuff, silty limestone and marl with minor andesitic tuff rocks. The economically most important Mn (Zakeri and Cheshmeh-sefid) deposits of Sabzevar zone occur within the marly tuff of this sequence. The Nudeh Cu-Zn volcanogenic massive sulfide (VMS) deposit is situated in the LLCVSS. The host-rock of deposits consists of alkali olivine basalt flow and tuffaceous silty sandstone. Mineralization occurs as stratiform blanket-like and tabular orebodies. Based on ore body structure, mineralogy, and ore fabric, we recognize three different ore facies in the Nudeh deposit: (1) a stringer zone, consisting of a discordant mineralization of sulfides forming a stockwork of sulfide-bearing quartz veins cutting the footwall volcano-sedimentary rocks; (2) a massive ore, consisting of massive replacement pyrite, chalcopyrite, sphalerite and Friedrichite with magnetite; (3) bedded ore, with laminated to disseminated pyrite, and chalcopyrite. Chloritization, silicification, sericitization and epidotization are the main wall-rock alterations; alteration intensity increases towards the stringer zone. The δ34S composition of the sulfides ranges from -1.5‰ to +3.69‰ with a general increase of δ34S ratios of massive ore facies to stockwork zone. The heavier values indicate that some of the sulfur was derived from seawater sulfate that was ultimately thermochemically reduced in deep hydrothermal reaction zones. Sulfur isotopes, along with sedimentological, textural, petrological, mineralogical, and geochemical evidences, suggest that this deposit should be classified as a Besshi-type VMS ore deposit.

Early Miocene sequence development across the New Jersey margin

USGS Publications Warehouse

Monteverde, D.H.; Mountain, Gregory S.; Miller, K.G.

2008-01-01

Sequence stratigraphy provides an understanding of the interplay between eustasy, sediment supply and accommodation in the sedimentary construction of passive margins. We used this approach to follow the early to middle Miocene growth of the New Jersey margin and analyse the connection between relative changes of sea level and variable sediment supply. Eleven candidate sequence boundaries were traced in high-resolution multi-channel seismic profiles across the inner margin and matched to geophysical log signatures and lithologic changes in ODP Leg 150X onshore coreholes. Chronologies at these drill sites were then used to assign ages to the intervening seismic sequences. We conclude that the regional and global correlation of early Miocene sequences suggests a dominant role of global sea-level change but margin progradation was controlled by localized sediment contribution and that local conditions played a large role in sequence formation and preservation. Lowstand deposits were regionally restricted and their locations point to both single and multiple sediment sources. The distribution of highstand deposits, by contrast, documents redistribution by along shelf currents. We find no evidence that sea level fell below the elevation of the clinoform rollover, and the existence of extensive lowstand deposits seaward of this inflection point indicates efficient cross-shelf sediment transport mechanisms despite the apparent lack of well-developed fluvial drainage. ?? 2008 The Authors. Journal compilation ?? 2008 Blackwell Publishing.

Mesoscale Particle-Based Model of Electrophoretic Deposition

DOE PAGES

Giera, Brian; Zepeda-Ruiz, Luis A.; Pascall, Andrew J.; ...

2016-12-20

In this paper, we present and evaluate a semiempirical particle-based model of electrophoretic deposition using extensive mesoscale simulations. We analyze particle configurations in order to observe how colloids accumulate at the electrode and arrange into deposits. In agreement with existing continuum models, the thickness of the deposit increases linearly in time during deposition. Resulting colloidal deposits exhibit a transition between highly ordered and bulk disordered regions that can give rise to an appreciable density gradient under certain simulated conditions. The overall volume fraction increases and falls within a narrow range as the driving force due to the electric field increasesmore » and repulsive intercolloidal interactions decrease. We postulate ordering and stacking within the initial layer(s) dramatically impacts the microstructure of the deposits. Finally, we find a combination of parameters, i.e., electric field and suspension properties, whose interplay enhances colloidal ordering beyond the commonly known approach of only reducing the driving force.« less

Solid-state dewetting of Au-Ni bi-layer films mediated through individual layer thickness and stacking sequence

NASA Astrophysics Data System (ADS)

Herz, Andreas; Theska, Felix; Rossberg, Diana; Kups, Thomas; Wang, Dong; Schaaf, Peter

2018-06-01

In the present work, the solid-state dewetting of Au-Ni bi-layer thin films deposited on SiO2/Si is systematically studied with respect to individual layer thickness and stacking sequence. For this purpose, a rapid heat treatment at medium temperatures is applied in order to examine void formation at the early stages of the dewetting. Compositional variations are realized by changing the thickness ratio of the bi-layer films, while the total thickness is maintained at 20 nm throughout the study. In the event of Au/Ni films annealed at 500 °C, crystal voids exposing the substrate are missing regardless of chemical composition. In reverse order, the number of voids per unit area in two-phase Au-Ni thin films is found to be governed by the amount of Au-rich material. At higher temperatures up to 650 °C, a decreased probability of nucleation comes at the expense of a major portion of cavities, resulting in the formation of bubbles in 15 nm Ni/5 nm Au bi-layers. Film buckling predominantly occurred at phase boundaries crossing the bubbles.

Molecular analysis of carbon monoxide-oxidizing bacteria associated with recent Hawaiian volcanic deposits.

PubMed

Dunfield, Kari E; King, Gary M

2004-07-01

Genomic DNA extracts from four sites at Kilauea Volcano were used as templates for PCR amplification of the large subunit (coxL) of aerobic carbon monoxide dehydrogenase. The sites included a 42-year-old tephra deposit, a 108-year-old lava flow, a 212-year-old partially vegetated ash-and-tephra deposit, and an approximately 300-year-old forest. PCR primers amplified coxL sequences from the OMP clade of CO oxidizers, which includes isolates such as Oligotropha carboxidovorans, Mycobacterium tuberculosis, and Pseudomonas thermocarboxydovorans. PCR products were used to create clone libraries that provide the first insights into the diversity and phylogenetic affiliations of CO oxidizers in situ. On the basis of phylogenetic and statistical analyses, clone libraries for each site were distinct. Although some clone sequences were similar to coxL sequences from known organisms, many sequences appeared to represent phylogenetic lineages not previously known to harbor CO oxidizers. On the basis of average nucleotide diversity and average pairwise difference, a forested site supported the most diverse CO-oxidizing populations, while an 1894 lava flow supported the least diverse populations. Neither parameter correlated with previous estimates of atmospheric CO uptake rates, but both parameters correlated positively with estimates of microbial biomass and respiration. Collectively, the results indicate that the CO oxidizer functional group associated with recent volcanic deposits of the remote Hawaiian Islands contains substantial and previously unsuspected diversity.

Facies analysis and sequence stratigraphy of neoproterozoic Platform deposits in Adrar of Mauritania, Taoudeni basin, West Africa

NASA Astrophysics Data System (ADS)

Benan, C. A. A.; Deynoux, M.

The Neoproterozoic and Palaeozoic Taoudeni basin forms the flat-lying and unmetamorphosed sedimentary cover of the West African Craton. In the western part of this basin, the Char Group and the lower part of the Atar Group make up a 400-m-thick Neoproterozoic siliciclastic succession which rests on the Palaeoproterozoic metamorphic and granitic basement. Five erosional bounding surfaces of regional extent have been identified in this succession. These surfaces separate five stratigraphic units with lithofacies associations ranging from fluvial to coastal and fluvial-, tide-, or wave-dominated shallow marine deposits. Owing to their regional extent and their position within the succession, the erosive bounding surfaces correspond to relative sea-level falls, and accordingly the five stratigraphic units they bound represent allocyclic transgressive-regressive depositional sequences (S1-S5). Changes in the nature of the deposits forming the transgressive-regressive cycles reflect landward or seaward shifts of the stacked sequences. These successive relative sea-level changes are related to the reactivation of basement faults and tilting during rifting of the Pan-Afro-Brasiliano supercontinent 1000 m.y. ago. The stromatolite bearing carbonate-shale sequences which form the rest of the Atar Group mark the onset of a quiet period of homogeneous subsidence contemporaneous with the Pan-African I oceanization 800-700 m.y. ago.

Integrated diagenetic and sequence stratigraphy of a late Oligocene-early Miocene, mixed-sediment platform (Austral Basin, southern Patagonia): Resolving base-level and paleoceanographic changes, and paleoaquifer characteristics

NASA Astrophysics Data System (ADS)

Dix, George R.; Parras, Ana

2014-06-01

A condensed (~ 20-m-thick) marine transgressive-highstand succession comprises the upper San Julián Formation (upper Oligocene-lower Miocene) of the northern retroarc Austral Basin, southern Patagonia. Mixed-sediment facies identify a shelf-interior setting, part of an overall warm-temperate regional platform of moderate energy. Giant oyster-dominated skeletal-hiatal accumulations along the maximum flooding surface and forming high-energy event beds in the highstand succession preserve relict micrite in protected shelter porosity, and identify periods of reduced sediment accumulation. The stratigraphic distribution of marine-derived glaucony and diagenetic carbonates is spatially related to sequence development. Depositional siderite coincides with prominent marine transgression, defining transient mixing of marine and meteoric waters across coastal-plain deposits. Chemically evolved autochthonous glaucony coincides with periods of extended seafloor exposure and transgressions that bracket the marine succession, and within the oyster-dominated skeletal accumulations. Seafloor cement, likely once magnesian calcite, formed in association with an encrusting/boring biota along the maximum flooding surface in concert with incursion of cool (11-13 °C) water. The cement is present locally in skeletal event beds in the highstand succession suggesting a possible association with high-order base-level change and cooler water. As the highstand succession coincides with elevated global sea level in the late Oligocene-early Miocene, the locally marine-cemented glauconitic skeletal event beds in the highstand succession may identify higher order glacio-eustatic control. Local stratal condensation, however, is best explained by regional differences in basement subsidence. In the burial realm, carbonate diagenesis produced layers of phreatic calcrete coincident with skeletal-rich deposits. Zeolite (clinoptilolite-K) cement is restricted to the lowermost marine transgressive interval probably due to initial elevated metastability of reworked weathered silicates. Clay (illite)-cement is restricted to siliciclastic-rich intervals wherein skeletal carbonate did not buffer pore-water pH. Diagenetic carbonate geochemistry (Sr, Na, and δ18O and δ13C) shows that, with burial, the transgressive and highstand system tracts developed as distinct paleoaquifers resulting from different proximities to meteoric recharge zones.

Eruptive history of the Ubehebe Crater cluster, Death Valley, California

NASA Astrophysics Data System (ADS)

Fierstein, Judy; Hildreth, Wes

2017-04-01

A sequence of late Holocene eruptions from the Ubehebe Crater cluster in Death Valley was short-lived, emplacing several phreatomagmatic and magmatic deposits. Seven craters form the main group, which erupted along a north-south alignment 1.5 km long. At least five more make a 500-m east-west alignment west of the main crater group. One more is an isolated shallow crater 400 m south of that alignment. All erupted through Miocene fanglomerate and sandstone, which are now distributed as comminuted matrix and lithic clasts in all Ubehebe deposits. Stratigraphic evidence showing that all Ubehebe strata were emplaced within a short time interval includes: (1) deposits from the many Ubehebe vents make a multi-package sequence that conformably drapes paleo-basement topography with no erosive gullying between emplacement units; (2) several crater rims that formed early in the eruptive sequence are draped smoothly by subsequent deposits; and (3) tack-welded to agglutinated spatter and bombs that erupted at various times through the sequence remained hot enough to oxidize the overlying youngest emplacement package. In addition, all deposits sufficiently consolidated to be drilled yield reliable paleomagnetic directions, with site mean directions showing no evidence of geomagnetic secular variation. Chemical analyses of juvenile components representing every eruptive package yield a narrow range in major elements [SiO2 (48.65-50.11); MgO (4.98-6.23); K2O (2.24-2.39)] and trace elements [Rb (28-33); Sr (1513-1588); Zr (373-404)]. Despite lithologic similarities, individual fall units can be traced outward from vent by recording layer thicknesses, maximum scoria and lithic sizes, and juvenile clast textural variations. This permits reconstruction of the eruptive sequence, which produced a variety of eruptive styles. The largest and northernmost of the craters, Ubehebe Crater, is the youngest of the group. Its largely phreatomagmatic deposits drape all of the others, thicken in paleogullies and thin over several newly created crater rims. Evidence in-hand virtually requires that the Ubehebe cluster of craters erupted over a brief time interval, not protracted over centuries.

Palaeoclimate characteristics in interior Siberia of MIS 6-2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands

NASA Astrophysics Data System (ADS)

Ashastina, Kseniia; Schirrmeister, Lutz; Fuchs, Margret; Kienast, Frank

2017-07-01

Syngenetic permafrost deposits formed extensively on and around the arising Beringian subcontinent during the Late Pleistocene sea level lowstands. Syngenetic deposition implies that all material, both mineral and organic, freezes parallel to sedimentation and remains frozen until degradation of the permafrost. Permafrost is therefore a unique archive of Late Pleistocene palaeoclimate. Most studied permafrost outcrops are situated in the coastal lowlands of northeastern Siberia; inland sections are, however, scarcely available. Here, we describe the stratigraphical, cryolithological, and geochronological characteristics of a permafrost sequence near Batagay in the Siberian Yana Highlands, the interior of the Sakha Republic (Yakutia), Russia, with focus on the Late Pleistocene Yedoma ice complex (YIC). The recently formed Batagay mega-thaw slump exposes permafrost deposits to a depth of up to 80 m and gives insight into a climate record close to Verkhoyansk, which has the most severe continental climate in the Northern Hemisphere. Geochronological dating (optically stimulated luminescence, OSL, and 14C ages) and stratigraphic implications delivered a temporal frame from the Middle Pleistocene to the Holocene for our sedimentological interpretations and also revealed interruptions in the deposition. The sequence of lithological units indicates a succession of several distinct climate phases: a Middle Pleistocene ice complex indicates cold stage climate. Then, ice wedge growth stopped due to highly increased sedimentation rates and eventually a rise in temperature. Full interglacial climate conditions existed during accumulation of an organic-rich layer - plant macrofossils reflected open forest vegetation existing under dry conditions during Marine Isotope Stage (MIS) 5e. The Late Pleistocene YIC (MIS 4-MIS 2) suggests severe cold-stage climate conditions. No alas deposits, potentially indicating thermokarst processes, were detected at the site. A detailed comparison of the permafrost deposits exposed in the Batagay thaw slump with well-studied permafrost sequences, both coastal and inland, is made to highlight common features and differences in their formation processes and palaeoclimatic histories. Fluvial and lacustrine influence is temporarily common in the majority of permafrost exposures, but has to be excluded for the Batagay sequence. We interpret the characteristics of permafrost deposits at this location as a result of various climatically induced processes that are partly seasonally controlled. Nival deposition might have been dominant during winter time, whereas proluvial and aeolian deposition could have prevailed during the snowmelt period and the dry summer season.

Stratigraphic, Granulometric and Geochemical Studies of a Major Plinian Eruption on Dominica, Lesser Antilles

NASA Astrophysics Data System (ADS)

Smith, A. L.; Daly, G.; Killingsworth, N.; Deuerling, K.; Schneider, S.; Fryxell, J. E.

2008-12-01

The island of Dominica, located in the center of the Lesser Antilles island arc has witnessed, probably within the last 100,000 years, three large volume Plinian eruptions. One of these, associated with the Morne Diablotins center, forms the Grande Savane pyroclastic flow fan, that extends off shore as a distinctive submarine feature for a distance of at least 14 km. Stratigraphical studies of road cuts and well-exposed sea cliffs indicate the fan is composed of an older unit composed of reworked deposits at the base followed by at least four sequences, based on the presence of paleosols, of block and ash flow deposits. The upper unit of block and ash flows is overlain, with no evidence of an intervening paleosol, by a sequence of ignimbrites and pumiceous surges (representing the Plinian eruption). There is no evidence of an initial Plinian fall deposit, so the lowest bed in the succession is an ignimbrite with a highly irregular base that cuts into the underlying block and ash flow deposits, the upper parts of which are colored red due to thermal effects. This lowest ignimbrite is welded (minimum porosity of 15%) throughout its thickness (maximum thickness of greater than 21 m), although a few outcrops near the margins show a thin (20-30 cm) non-welded but lithified zone beneath the welded zone. The remainder of the sequence is composed of lithified ignimbrite that can be subdivided into three units separated by pumiceous surge layers. The ignimbrite succession is overlain, with no obvious break, by a thin fall deposit containing accretionary lapilli and gas cavities, followed by three pumiceous surge deposits (lower and upper show planar stratification and the middle surge shows massive bedding); towards the north the upper two surge deposits are separated by thin pumiceous lapilli fall and ash fall deposits. This surge sequence extends laterally outside of the main area of ignimbrite deposition. The pumice clasts from the ignimbrites are andesitic in composition and show essentially no variation up stratigraphy. In contrast, the surges are more variable in composition, ranging from andesite to dacite. Modeling of these data will provide information on the dynamics of this major Plinian eruption including the effects of water/magma interaction.

A Deep Insight Into the Sialotranscriptome of the Chagas Disease Vector, Panstrongylus megistus (Hemiptera: Heteroptera)

PubMed Central

Ribeiro, José M. C.; Schwarz, Alexandra; Francischetti, Ivo M. B.

2015-01-01

Saliva of blood-sucking arthropods contains a complex cocktail of pharmacologically active compounds that assists feeding by counteracting their hosts’ hemostatic and inflammatory reactions. Panstrongylus megistus (Burmeister) is an important vector of Chagas disease in South America, but despite its importance there is only one salivary protein sequence publicly deposited in GenBank. In the present work, we used Illumina technology to disclose and publicly deposit 3,703 coding sequences obtained from the assembly of >70 million reads. These sequences should assist proteomic experiments aimed at identifying pharmacologically active proteins and immunological markers of vector exposure. A supplemental file of the transcriptome and deducted protein sequences can be obtained from http://exon.niaid.nih.gov/transcriptome/P_megistus/Pmeg-web.xlsx. PMID:26334808

Architectures and criteria for the design of high efficiency organic photovoltaic cells

DOEpatents

Rand, Barry; Forrest, Stephen R; Pendergrast Burk, Diane

2015-03-31

A method for fabricating an organic photovoltaic cell includes providing a first electrode; depositing a series of at least seven layers onto the first electrode, each layer consisting essentially of a different organic semiconductor material, the organic semiconductor material of at least an intermediate layer of the sequence being a photoconductive material; and depositing a second electrode onto the sequence of at least seven layers. One of the first electrode and the second electrode is an anode and the other is a cathode. The organic semiconductor materials of the series of at least seven layers are arranged to provide a sequence of decreasing lowest unoccupied molecular orbitals (LUMOs) and a sequence of decreasing highest occupied molecular orbitals (HOMOs) across the series from the anode to the cathode.

Distinguishing thrust sequences in gravity-driven fold and thrust belts

NASA Astrophysics Data System (ADS)

Alsop, G. I.; Weinberger, R.; Marco, S.

2018-04-01

Piggyback or foreland-propagating thrust sequences, where younger thrusts develop in the footwalls of existing thrusts, are generally assumed to be the typical order of thrust development in most orogenic settings. However, overstep or 'break-back' sequences, where later thrusts develop above and in the hangingwalls of earlier thrusts, may potentially form during cessation of movement in gravity-driven mass transport deposits (MTDs). In this study, we provide a detailed outcrop-based analysis of such an overstep thrust sequence developed in an MTD in the southern Dead Sea Basin. Evidence that may be used to discriminate overstep thrusting from piggyback thrust sequences within the gravity-driven fold and thrust belt includes upright folds and forethrusts that are cut by younger overlying thrusts. Backthrusts form ideal markers that are also clearly offset and cut by overlying younger forethrusts. Portions of the basal detachment to the thrust system are folded and locally imbricated in footwall synclines below forethrust ramps, and these geometries also support an overstep sequence. However, new 'short-cut' basal detachments develop below these synclines, indicating that movement continued on the basal detachment rather than it being abandoned as in classic overstep sequences. Further evidence for 'synchronous thrusting', where movement on more than one thrust occurs at the same time, is provided by displacement patterns on sequences of thrust ramp imbricates that systematically increases downslope towards the toe of the MTD. Older thrusts that initiate downslope in the broadly overstep sequence continue to move and therefore accrue greater displacements during synchronous thrusting. Our study provides a template to help distinguish different thrust sequences in both orogenic settings and gravity-driven surficial systems, with displacement patterns potentially being imaged in seismic sections across offshore MTDs.

An exploratory drilling exhaustion sequence plot program

USGS Publications Warehouse

Schuenemeyer, J.H.; Drew, L.J.

1977-01-01

The exhaustion sequence plot program computes the conditional area of influence for wells in a specified rectangular region with respect to a fixed-size deposit. The deposit is represented by an ellipse whose size is chosen by the user. The area of influence may be displayed on computer printer plots consisting of a maximum of 10,000 grid points. At each point, a symbol is presented that indicates the probability of that point being exhausted by nearby wells with respect to a fixed-size ellipse. This output gives a pictorial view of the manner in which oil fields are exhausted. In addition, the exhaustion data may be used to estimate the number of deposits remaining in a basin. ?? 1977.

Comparison of Metabolic Pathways in Escherichia coli by Using Genetic Algorithms.

PubMed

Ortegon, Patricia; Poot-Hernández, Augusto C; Perez-Rueda, Ernesto; Rodriguez-Vazquez, Katya

2015-01-01

In order to understand how cellular metabolism has taken its modern form, the conservation and variations between metabolic pathways were evaluated by using a genetic algorithm (GA). The GA approach considered information on the complete metabolism of the bacterium Escherichia coli K-12, as deposited in the KEGG database, and the enzymes belonging to a particular pathway were transformed into enzymatic step sequences by using the breadth-first search algorithm. These sequences represent contiguous enzymes linked to each other, based on their catalytic activities as they are encoded in the Enzyme Commission numbers. In a posterior step, these sequences were compared using a GA in an all-against-all (pairwise comparisons) approach. Individual reactions were chosen based on their measure of fitness to act as parents of offspring, which constitute the new generation. The sequences compared were used to construct a similarity matrix (of fitness values) that was then considered to be clustered by using a k-medoids algorithm. A total of 34 clusters of conserved reactions were obtained, and their sequences were finally aligned with a multiple-sequence alignment GA optimized to align all the reaction sequences included in each group or cluster. From these comparisons, maps associated with the metabolism of similar compounds also contained similar enzymatic step sequences, reinforcing the Patchwork Model for the evolution of metabolism in E. coli K-12, an observation that can be expanded to other organisms, for which there is metabolism information. Finally, our mapping of these reactions is discussed, with illustrations from a particular case.

Comparison of Metabolic Pathways in Escherichia coli by Using Genetic Algorithms

PubMed Central

Ortegon, Patricia; Poot-Hernández, Augusto C.; Perez-Rueda, Ernesto; Rodriguez-Vazquez, Katya

2015-01-01

In order to understand how cellular metabolism has taken its modern form, the conservation and variations between metabolic pathways were evaluated by using a genetic algorithm (GA). The GA approach considered information on the complete metabolism of the bacterium Escherichia coli K-12, as deposited in the KEGG database, and the enzymes belonging to a particular pathway were transformed into enzymatic step sequences by using the breadth-first search algorithm. These sequences represent contiguous enzymes linked to each other, based on their catalytic activities as they are encoded in the Enzyme Commission numbers. In a posterior step, these sequences were compared using a GA in an all-against-all (pairwise comparisons) approach. Individual reactions were chosen based on their measure of fitness to act as parents of offspring, which constitute the new generation. The sequences compared were used to construct a similarity matrix (of fitness values) that was then considered to be clustered by using a k-medoids algorithm. A total of 34 clusters of conserved reactions were obtained, and their sequences were finally aligned with a multiple-sequence alignment GA optimized to align all the reaction sequences included in each group or cluster. From these comparisons, maps associated with the metabolism of similar compounds also contained similar enzymatic step sequences, reinforcing the Patchwork Model for the evolution of metabolism in E. coli K-12, an observation that can be expanded to other organisms, for which there is metabolism information. Finally, our mapping of these reactions is discussed, with illustrations from a particular case. PMID:25973143

Complete Genome Sequences of Two Vesicular Stomatitis Virus Isolates Collected in Mexico.

PubMed

Velazquez-Salinas, Lauro; Isa, Pavel; Pauszek, Steven J; Rodriguez, Luis L

2017-09-14

We report two full-genome sequences of vesicular stomatitis New Jersey virus (VSNJV) obtained by Illumina next-generation sequencing of RNA isolated from epithelial suspensions of cattle naturally infected in Mexico. These genomes represent the first full-genome sequences of vesicular stomatitis New Jersey viruses circulating in Mexico deposited in the GenBank database.

Microbial diversity in nonsulfur, sulfur and iron geothermal steam vents.

PubMed

Benson, Courtney A; Bizzoco, Richard W; Lipson, David A; Kelley, Scott T

2011-04-01

Fumaroles, commonly called steam vents, are ubiquitous features of geothermal habitats. Recent studies have discovered microorganisms in condensed fumarole steam, but fumarole deposits have proven refractory to DNA isolation. In this study, we report the development of novel DNA isolation approaches for fumarole deposit microbial community analysis. Deposit samples were collected from steam vents and caves in Hawaii Volcanoes National Park, Yellowstone National Park and Lassen Volcanic National Park. Samples were analyzed by X-ray microanalysis and classified as nonsulfur, sulfur or iron-dominated steam deposits. We experienced considerable difficulty in obtaining high-yield, high-quality DNA for cloning: only half of all the samples ultimately yielded sequences. Analysis of archaeal 16S rRNA gene sequences showed that sulfur steam deposits were dominated by Sulfolobus and Acidianus, while nonsulfur deposits contained mainly unknown Crenarchaeota. Several of these novel Crenarchaeota lineages were related to chemoautotrophic ammonia oxidizers, indicating that fumaroles represent a putative habitat for ammonia-oxidizing Archaea. We also generated archaeal and bacterial enrichment cultures from the majority of the deposits and isolated members of the Sulfolobales. Our results provide the first evidence of Archaea in geothermal steam deposits and show that fumaroles harbor diverse and novel microbial lineages. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Reworked calcretes: their significance in the reconstruction of alluvial sequences (Permian and Triassic, Minorca, Balearic Islands, Spain)

NASA Astrophysics Data System (ADS)

Gómez-Gras, D.; Alonso-Zarza, A. M.

2003-05-01

The Permian and Triassic of Minorca (Balearic Islands) consists of a 670-m-thick, red, alluvial succession that includes in situ calcrete profiles and reworked calcrete material. In the Permian succession, the calcretes vary from laminar forms developed on the Carboniferous basement to weakly developed nodular calcretes in fluvial sediments. The palaeosols in the Triassic are mostly dolomitic, and the profiles reach up to Stage III of soil development (Spec. Pap.-Geol. Surv. Am. 203, (1995) 1). The clasts, formed through reworking of the palaeosol profiles, are about 0.5-10 cm across and include mosaics of calcite/dolomite crystals, brecciated clasts, rhizolith fragments, and aggregates of clay and/or silt. These clasts appear in three different types of deposits. Type 1 corresponds to lenticular bodies that fill small scour surfaces, and consists only of intraformational conglomerates. These deposits are interpreted as ephemeral channels and sheet-floods that represent the interfluvial drainage systems that captured only the precipitation falling on the alluvial plain. Type 2 includes sand dune 3-D bodies with flat bottoms and convex tops. These bodies are about 20 cm high and 2 m wide, and were formed by floodwaters that flowed down the levees of the major streams. Type 3 channel deposits contain reworked calcretes and extrabasinal clasts, which overlie erosive surfaces and are found in layers within cross-bedded sandstones and conglomerates. These are interpreted as channel-floor lag deposits of major channels that entered from distant uplands and drained the alluvial plain. Variations in the aggradation rates of the floodplain resulted in five different infill stages. In the lowstand to early transgressive interval, as in stages I (P1) and IV (B1), the fluvial deposits filled palaeovalleys; calcretes and reworked calcrete deposits were of difficult formation (apart from terraces) and preservation. Accommodation space was at its greatest in the transgressive, stages II (P2) and V (B2). This caused the greatest aggradation of the floodplains, which are formed of thick sequences of fine-grained sediments, isolated meandering channels, weakly developed calcretes (compound) and reworked calcrete deposits, mostly of types 1 and 2. The density of channels notably increased in stage III (P3), highstand interval, because of the reduction of accommodation space, this could favour the formation of composite or even cumulative palaeosols, but of difficult preservation. Reworked calcrete deposits are mostly of type 3, but types 1 and 2 are also recognised. The reworked calcrete deposits are an important part of the Permian and Triassic fluvial sediments and their occurrence and characteristics are important in order to interpret the infill of terrestrial basins and the construction of floodplains.

Genetic and grade and tonnage models for sandstone-hosted roll-type uranium deposits, Texas Coastal Plain, USA

USGS Publications Warehouse

Hall, Susan M.; Mihalasky, Mark J.; Tureck, Kathleen; Hammarstrom, Jane M.; Hannon, Mark

2017-01-01

The coincidence of a number of geologic and climatic factors combined to create conditions favorable for the development of mineable concentrations of uranium hosted by Eocene through Pliocene sandstones in the Texas Coastal Plain. Here 254 uranium occurrences, including 169 deposits, 73 prospects, 6 showings and 4 anomalies, have been identified. About 80 million pounds of U3O8 have been produced and about 60 million pounds of identified producible U3O8 remain in place. The development of economic roll-type uranium deposits requires a source, large-scale transport of uranium in groundwater, and deposition in reducing zones within a sedimentary sequence. The weight of the evidence supports a source from thick sequences of volcanic ash and volcaniclastic sediment derived mostly from the Trans-Pecos volcanic field and Sierra Madre Occidental that lie west of the region. The thickest accumulations of source material were deposited and preserved south and west of the San Marcos arch in the Catahoula Formation. By the early Oligocene, a formerly uniformly subtropical climate along the Gulf Coast transitioned to a zoned climate in which the southwestern portion of Texas Coastal Plain was dry, and the eastern portion humid. The more arid climate in the southwestern area supported weathering of volcanic ash source rocks during pedogenesis and early diagenesis, concentration of uranium in groundwater and movement through host sediments. During the middle Tertiary Era, abundant clastic sediments were deposited in thick sequences by bed-load dominated fluvial systems in long-lived channel complexes that provided transmissive conduits favoring transport of uranium-rich groundwater. Groundwater transported uranium through permeable sandstones that were hydrologically connected with source rocks, commonly across formation boundaries driven by isostatic loading and eustatic sea level changes. Uranium roll fronts formed as a result of the interaction of uranium-rich groundwater with either (1) organic-rich debris adjacent to large long-lived fluvial channels and barrier–bar sequences or (2) extrinsic reductants entrained in formation water or discrete gas that migrated into host units via faults and along the flanks of salt domes and shale diapirs. The southwestern portion of the region, the Rio Grande embayment, contains all the necessary factors required for roll-type uranium deposits. However, the eastern portion of the region, the Houston embayment, is challenged by a humid environment and a lack of source rock and transmissive units, which may combine to preclude the deposition of economic deposits. A grade and tonnage model for the Texas Coastal Plain shows that the Texas deposits represent a lower tonnage subset of roll-type deposits that occur around the world, and required aggregation of production centers into deposits based on geologic interpretation for the purpose of conducting a quantitative mineral resource assessment.

Late-kinematic timing of orogenic gold deposits and significance for computer-based exploration techniques with emphasis on the Yilgarn Block, Western Australia

USGS Publications Warehouse

Groves, D.I.; Goldfarb, R.J.; Knox-Robinson, C. M.; Ojala, J.; Gardoll, S.; Yun, G.Y.; Holyland, P.

2000-01-01

Orogenic gold deposits are a widespread coherent group of epigenetic ore deposits that are sited in accretionary or collisional orogens. They formed over a large crustal-depth range from deep-seated low-salinity H2O-CO2 + CH4 + N2 ore fluids and with Au transported as thio-complexes. Regional structures provide the main control on deposit distribution. In many terranes, first-order faults or shear zones appear to have controlled regional fluid flow, with greatest ore-fluid fluxes in, and adjacent to, lower-order faults, shear zones and/or large folds. Highly competent and/or chemically reactive rocks are the most common hosts to the larger deposits. Focusing of supralithostatic ore fluids into dilatant zones appears to occur late during the evolutionary history of the host terranes, normally within D3 or D4 in a D1-D4 deformation sequence. Reactivation of suitably oriented pre-existing structures during a change in far-field stress orientation is a factor common to many deposits, and repeated reactivation may account for multiple mineralization episodes in some larger deposits. Absolute robust ages of mineralization support their late-kinematic timing, and, in general, suggest that deposits formed diachronously towards the end of the 100 to 200 m.y. long evolutionary history of hosting orogens. For example, in the Yilgarn Block, a region specifically emphasised in this study, orogenic gold deposits formed in the time interval between 40 and 90 m.y., with most about 60 to 70 m.y., after the youngest widespread basic-ultrabasic volcanism and towards the end of felsic magmatism. The late timing of orogenic gold deposits is pivotal to geologically-based exploration methodologies. This is because the present structural geometries of: (i) the deposits, (ii) the hosting goldfields, and (iii) the enclosing terranes are all essentially similar to those during gold mineralization, at least in their relative position to each other. Thus, interpretation of geological maps and cross-sections and three-dimensional models can be used to accurately simulate the physical conditions that existed at the time of ore deposition. It is particularly significant that the deposits are commonly related to repetitive and predictable geometries, such as structural heterogeneities within or adjacent to first-order structures, around rigid granitoid bodies, or in specific "locked-up" fold-thrust structures. Importantly, the two giant greenstone-hosted goldfields, Kalgoorlie and Timmins, show a remarkably similar geometry at the regional scale. Computer-based stress mapping and GIS-based prospectivity mapping are two computer-based quantitative methodologies that can utilize and take advantage of the late timing aspect of this deposit type to provide important geological aids in exploration, both in broad regions and more localized goldfields. Both require an accurate and consistent solid geology map, stress mapping requires knowledge of the far-field stresses during mineralization, and the empirical prospectivity mapping requires data from a significant number of known deposits in the terrane. The Kalgoorlie Terrane, in the Yilgarn Block, meets these criteria, and illustrates the potential of these methodologies in the exploration for orogenic gold deposits. Low minimum stress anomalies, interpreted to represent dilational zones during gold-related deformation, coincide well with the positions of known goldfields rather than individual gold deposits in the terrane, and there are additional as-yet unexplained anomalies. The prospectivity analysis confirms that predictable and repetitive factors controlling the siting of deposits are: (i) proximity to, and orientation and curvature of, granitoid-greenstone contacts, (ii) proximity to segments of crustal faults which strike in a preferred direction, (iii) proximity to specific lithological contacts which have similar preferred strike, (iv) proximity to anticlinal structures, and (v) the presence of preferred

Late Devonian shale deposition based on known and predicted occurrence of Foerstia in Michigan basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, R.D.

The fossil Foerstia (Protosalvinia) marks a time zone within Late Devonian shale sequences in the eastern US. Its recent discovery in Michigan has led to more accurate correlations among the three large eastern basins. Subdivisions of the Devonian-Mississippi shale sequence in Michigan based on gamma-ray correlations reveal an idealized black shale geometry common to other eastern black shales, such as the Sunbury of Michigan and Ohio, the Clegg Creek of Indiana, the Dunkirk of Pennsylvania and New York, and the lower Huron of Ohio and West Virginia. In Michigan, Foerstia occurs at a stratigraphic position postulated to mark a majormore » change in depositional conditions and source areas. This position strengthens the physical and paleontologic evidence for a formal division of the Antrim. Isopach maps of the shale sequence above and below Foerstia show a relatively uniform and continuous black shale deposit (units 1A, 1B, and 1C) below Foerstia. This deposit is unlike the wedge of sediment found above Foerstia, which is composed of a western facies (Ellsworth) and an eastern facies (upper Antrim) that should be combined in a single stratigraphic unit conforming to Forgotson's concept of a format.« less

Paleosoils in the loess deposits of eastern Uzbekistan

NASA Astrophysics Data System (ADS)

Abdunazarov, U. K.; Stelmakh, A. G.

2010-12-01

Loess deposits of the eastern Uzbekistan are difficult to study the stratigraphy of the object. Clarification of the relationship of age and genetic features of the considered entities by traditional methods is difficult due to scarcity of remnants of the fauna and flora, the active Quaternary tectonics, the homogeneity of the rocks, especially the formation of loess sequences, specific conditions of geological and tectonic development, etc. In this regard, particularly relevant is the study of loess deposits by paleosoils subdivision and correlation. Paleosoils, which are present in the sections of loess sequences, distinct from loess-like loams, dividing them among themselves. Color these paleosoils noticeable brownish or brown, while the loess is a powdery mildew gray rock. Typically, the general scheme of occurrence of loess cover is linked with levels of relief mountainous areas. Recent studies show that the loess in the piedmont plains overlie a complex manner and include uneven paleosoils. Therefore, loess sequences of different geomorphological levels from the lower parts of slopes to the watershed have been studied in research paleosoils. The scheme was drawn up as a result of the studies. This scheme shows the main horizons paleosoils in loess deposits. Even-aged paleosoils and share their loess were identified in this scheme.

Glacial morphology and depositional sequences of the Antarctic Continental Shelf

USGS Publications Warehouse

ten Brink, Uri S.; Schneider, Christopher

1995-01-01

Proposes a simple model for the unusual depositional sequences and morphology of the Antarctic continental shelf. It considers the regional stratal geometry and the reversed morphology to be principally the results of time-integrated effects of glacial erosion and sedimentation related to the location of the ice grounding line. The model offers several guidelines for stratigraphic interpretation of the Antarctic shelf and a Northern Hemisphere shelf, both of which were subject to many glacial advances and retreats. -Authors

Banded iron-formations of late Proterozoic age in the central eastern desert, Egypt: geology and tectonic setting.

USGS Publications Warehouse

Sims, P.K.; James, H.L.

1984-01-01

Iron-formation occurs as stratigraphic units within a layered andesite-basalt sequence. The sequence is metamorphosed to greenschist facies, intruded by syntectonic granodiorite and post-tectonic granite, and complexly deformed and grossly fragmented; the rocks are allochthonous along thrust faults. The iron deposits are chemical precipitates, accumulated during lulls in volcanism, apparently in an intraoceanic island-arc environment. The deposits are of the Algoma type of iron-formation.-G.J.N.

A physical map of a BAC clone contig covering the entire autosome insertion between ovine MHC Class IIa and IIb

PubMed Central

2012-01-01

Background The ovine Major Histocompatibility Complex (MHC) harbors genes involved in overall resistance/susceptibility of the host to infectious diseases. Compared to human and mouse, the ovine MHC is interrupted by a large piece of autosome insertion via a hypothetical chromosome inversion that constitutes ~25% of ovine chromosome 20. The evolutionary consequence of such an inversion and an insertion (inversion/insertion) in relation to MHC function remains unknown. We previously constructed a BAC clone physical map for the ovine MHC exclusive of the insertion region. Here we report the construction of a high-density physical map covering the autosome insertion in order to address the question of what the inversion/insertion had to do with ruminants during the MHC evolution. Results A total of 119 pairs of comparative bovine oligo primers were utilized to screen an ovine BAC library for positive clones and the orders and overlapping relationships of the identified clones were determined by DNA fingerprinting, BAC-end sequencing, and sequence-specific PCR. A total of 368 positive BAC clones were identified and 108 of the effective clones were ordered into an overlapping BAC contig to cover the consensus region between ovine MHC class IIa and IIb. Therefore, a continuous physical map covering the entire ovine autosome inversion/insertion region was successfully constructed. The map confirmed the bovine sequence assembly for the same homologous region. The DNA sequences of 185 BAC-ends have been deposited into NCBI database with the access numbers HR309252 through HR309068, corresponding to dbGSS ID 30164010 through 30163826. Conclusions We have constructed a high-density BAC clone physical map for the ovine autosome inversion/insertion between the MHC class IIa and IIb. The entire ovine MHC region is now fully covered by a continuous BAC clone contig. The physical map we generated will facilitate MHC functional studies in the ovine, as well as the comparative MHC evolution in ruminants. PMID:22897909

Sedimentary manganese metallogenesis in response to the evolution of the Earth system

NASA Astrophysics Data System (ADS)

Roy, Supriya

2006-08-01

The concentration of manganese in solution and its precipitation in inorganic systems are primarily redox-controlled, guided by several Earth processes most of which were tectonically induced. The Early Archean atmosphere-hydrosphere system was extremely O 2-deficient. Thus, the very high mantle heat flux producing superplumes, severe outgassing and high-temperature hydrothermal activity introduced substantial Mn 2+ in anoxic oceans but prevented its precipitation. During the Late Archean, centered at ca. 2.75 Ga, the introduction of Photosystem II and decrease of the oxygen sinks led to a limited buildup of surface O 2-content locally, initiating modest deposition of manganese in shallow basin-margin oxygenated niches (e.g., deposits in India and Brazil). Rapid burial of organic matter, decline of reduced gases from a progressively oxygenated mantle and a net increase in photosynthetic oxygen marked the Archean-Proterozoic transition. Concurrently, a massive drawdown of atmospheric CO 2 owing to increased weathering rates on the tectonically expanded freeboard of the assembled supercontinents caused Paleoproterozoic glaciations (2.45-2.22 Ga). The spectacular sedimentary manganese deposits (at ca. 2.4 Ga) of Transvaal Supergroup, South Africa, were formed by oxidation of hydrothermally derived Mn 2+ transferred from a stratified ocean to the continental shelf by transgression. Episodes of increased burial rate of organic matter during ca. 2.4 and 2.06 Ga are correlatable to ocean stratification and further rise of oxygen in the atmosphere. Black shale-hosted Mn carbonate deposits in the Birimian sequence (ca. 2.3-2.0 Ga), West Africa, its equivalents in South America and those in the Francevillian sequence (ca. 2.2-2.1 Ga), Gabon are correlatable to this period. Tectonically forced doming-up, attenuation and substantial increase in freeboard areas prompted increased silicate weathering and atmospheric CO 2 drawdown causing glaciation on the Neoproterozoic Rodinia supercontinent. Tectonic rifting and mantle outgassing led to deglaciation. Dissolved Mn 2+ and Fe 2+ concentrated earlier in highly saline stagnant seawater below the ice cover were exported to shallow shelves by transgression during deglaciation. During the Sturtian glacial-interglacial event (ca. 750-700 Ma), interstratified Mn oxide and BIF deposits of Damara sequence, Namibia, was formed. The Varangian (≡ Marinoan; ca. 600 Ma) cryogenic event produced Mn oxide and BIF deposits at Urucum, Jacadigo Group, Brazil. The Datangpo interglacial sequence, South China (Liantuo-Nantuo ≡ Varangian event) contains black shale-hosted Mn carbonate deposits. The Early Paleozoic witnessed several glacioeustatic sea level changes producing small Mn carbonate deposits of Tiantaishan (Early Cambrian) and Taojiang (Mid-Ordovician) in black shale sequences, China, and the major Mn oxide-carbonate deposits of Karadzhal-type, Central Kazakhstan (Late Devonian). The Mesozoic period of intense plate movements and volcanism produced greenhouse climate and stratified oceans. During the Early Jurassic OAE, organic-rich sediments host many Mn carbonate deposits in Europe (e.g., Úrkút, Hungary) in black shale sequences. The Late Jurassic giant Mn Carbonate deposit at Molango, Mexico, was also genetically related to sea level change. Mn carbonates were always derived from Mn oxyhydroxides during early diagenesis. Large Mn oxide deposits of Cretaceous age at Groote Eylandt, Australia and Imini-Tasdremt, Morocco, were also formed during transgression-regression in greenhouse climate. The Early Oligocene giant Mn oxide-carbonate deposit of Chiatura (Georgia) and Nikopol (Ukraine) were developed in a similar situation. Thereafter, manganese sedimentation was entirely shifted to the deep seafloor and since ca. 15 Ma B.P. was climatically controlled (glaciation-deglaciation) assisted by oxygenated polar bottom currents (AABW, NADW). The changes in climate and the sea level were mainly tectonically forced.

Synovial deposition of wild-type transthyretin-derived amyloid in knee joint osteoarthritis patients.

PubMed

Takanashi, Tetsuo; Matsuda, Masayuki; Yazaki, Masahide; Yamazaki, Hideshi; Nawata, Masashi; Katagiri, Yoshiki; Ikeda, Shu-Ichi

2013-09-01

To investigate histological features of deposited amyloid in the synovial tissue and its clinical significance in knee joint osteoarthritis (OA) patients. We prospectively enrolled 232 consecutive patients who underwent arthroplasty or total replacement of the knee joint for treatment of OA. Congo red staining and immunohistochemistry were performed in the synovial tissue obtained at surgery. When transthyretin (TTR)-derived amyloid was positive, we analyzed all 4 exons of the TTR gene using the direct DNA sequencing method in order to detect mutations. We analyzed 322 specimens in this study. Twenty-six specimens (8.1%) obtained from 21 patients (5 men and 16 women; mean, 79.0 ± 4.6 years) showed deposition of amyloid, which was positively stained with the anti-TTR antibody. Eighteen patients showed inhomogeneous accumulations of amyloid in the loose connective tissue under the synovial epithelia sometimes with nodule formation, while in the remaining three, small vessels in the adipose tissue were involved. Medical records of these patients revealed nothing remarkable in the clinical course, laboratory data or macroscopic intraarticular findings at surgery. No mutations were detectable in the TTR gene analysis. Wild-type TTR-derived amyloid may affect the synovial tissue as a result of long-term mechanical stress or as a part of senile systemic amyloidosis in approximately 8% of knee joint OA patients. No obvious clinical significance was found in synovial deposition of amyloid.

Attribute of trace fossils of Laisong flysch sediments, Manipur, India

NASA Astrophysics Data System (ADS)

Khaidem, Kumar S.; Rajkumar, Hemanta S.; Soibam, Ibotombi

2015-07-01

The depositional basin in which the Late Eocene-Early Oligocene Laisong flysch sediments Barail Group, Manipur region (Indo-Myanmar ranges) have been deposited is generally considered to be of deep marine environment. However, field observation indicates the presence of many shallow environment signature characteristics of marginal to sublittoral marine settings, in addition to the general occurrence of deep marine turbidites. To address this aspect, ichnological analyses of the Laisong Formation has been attempted for elucidating palaeoenvironmental setting prevalent during the deposition of these sediments. Presence of 36 ichnospecies belonging to 33 ichnogenera has so far been identified. The ichnospecies may be grouped into different ichnofacies such as Skolithos-Cruziana mixed ichnofacies, Cruziana ichnofacies, Skolithos ichnofacies, Zoophycos ichnofacies, Nereites ichnofacies and Teredolites ichnofacies which decrease in abundance in this order of sequence with Skolithos-Cruziana mixed ichnofacies being the most dominant. The above-mentioned ichnofacies are found associated with sedimentary structures such as large sole marks, parallel laminations, massive and structureless beds, rip-up clasts, etc., which are characteristics of submarine fan deposits below the storm wave base and current ripples, herringbone structures, hummocky cross stratifications, pot casts, rain prints, etc., that marked shallow marginal marine setting such as tidal flats, deltas and shoreface. With such observations it is very likely that the Laisong sediments were formed in a tectonically active basin with varied bathymetric ranges indicating alternate transgressive and regressive nature.

Petrogenesis and depositional history of felsic pyroclastic rocks from the Melka Wakena archaeological site-complex in South central Ethiopia

NASA Astrophysics Data System (ADS)

Resom, Angesom; Asrat, Asfawossen; Gossa, Tegenu; Hovers, Erella

2018-06-01

The Melka Wakena archaeological site-complex is located at the eastern rift margin of the central sector of the Main Ethiopian Rift (MER), in south central Ethiopia. This wide, gently sloping rift shoulder, locally called the "Gadeb plain" is underlain by a succession of primary pyroclastic deposits and intercalated fluvial sediments as well as reworked volcaniclastic rocks, the top part of which is exposed by the Wabe River in the Melka Wakena area. Recent archaeological survey and excavations at this site revealed important paleoanthropological records. An integrated stratigraphic, petrological, and major and trace element geochemical study has been conducted to constrain the petrogenesis of the primary pyroclastic deposits and the depositional history of the sequence. The results revealed that the Melka Wakena pyroclastic deposits are a suite of mildly alkaline, rhyolitic pantellerites (ash falls, pumiceous ash falls and ignimbrites) and slightly dacitic ash flows. These rocks were deposited by episodic volcanic eruptions during early to middle Pleistocene from large calderas along the Wonji Fault Belt (WFB) in the central sector of the MER and from large silicic volcanic centers at the eastern rift shoulder. The rhyolitic ash falls, pumiceous ash falls and ignimbrites have been generated by fractional crystallization of a differentiating basaltic magma while the petrogenesis of the slightly dacitic ash flows involved some crustal contamination and assimilation during fractionation. Contemporaneous fluvial activities in the geomorphologically active Gadeb plain deposited overbank sedimentary sequences (archaeology bearing conglomerates and sands) along meandering river courses while a dense network of channels and streams have subsequently down-cut through the older volcanic and sedimentary sequences, redepositing the reworked volcaniclastic sediments further downstream.

Hidden Ice Worlds - Pleistocene glacigenic deposits in Essex, England. Application of the novel systematic approach to thin-section description.

NASA Astrophysics Data System (ADS)

Leszczynska, Karolina; Boreham, Julie; Boreham, Steve

2013-04-01

In the 'Hidden Ice Worlds' research project a novel systematic approach for thin-section description (Leszczynska et al., 2011) is applied to analyse the internal structure of 8 m thick periglacially disturbed sequence from the Royal Oak Pit - a small disused quarry in East Anglia, Essex, east of Chelmsford, near Danbury. Danbury Hill is situated on the south-eastern margin of the Elsterian (Anglian) till sheet. This area was glaciated only once, during the Pleistocene, Elsterian (Anglian) glaciation (480-420 ka BP), however two local ice-sheet margin fluctuations are envisaged (inter alia Turner, 1970 and others). The stratigraphical sequence of the Royal Oak Pit comprises: massive gravel, arranged in sheets, overlain by fine silty-clay and silty-sand with ripple marks and planar cross beds, overlain by a 50 cm thick unit of massive gravel gradually changing into periglacially disturbed silty-clayey-gravel with the bottom 50 cm of fine laminated silty clay. This sequence is situated on the lee side of Danbury Hill, at over 50 m OD. This is an atypical location for the periglacially disturbed deposits of such a substantial thickness (up to 8 m), which usually occur in the lower areas. The deposits at this site were investigated at a macro-scale using field-section logging, ground penetrating radar survey, clast lithology, clay mineralogy analysis and loss-on-ignition and at a micro-scale using thin-section analysis. There are two main aims of the project presented: • To describe the genesis and to discern the main processes associated with the formation of the unusually thick periglacially disturbed unit at the Danbury Hill slope and • To test the novel, tree-based, systematic approach as a guiding tool for thin for thin-section description of Quaternary deposits (Leszczynska et al., 2011). The results of the micromorphological analyses of the deposits from the Royal Oak Pit allow a new hypothesis for the origin of the sequence to be put forward. The main process responsible for the evolution of the deposits consist of multiple phases of freezing and thawing of the deposit and associated physical reworking, subsequent to Elsterian (Anglian). Inversion of the topography is proposed as a necessary condition for the formation and preservation of the periglacially disturbed sequence on hill slope at such elevated location. The novel systematic approach proved to be a useful tool in guiding the thin-section description, regardless of the type of the deposit and the aim of the research. Reference: Leszczynska, K., Boreham, J. and Boreham, S., 2011. A novel methodological approach for thin-section description and its application to periglacially disturbed Pleistocene deposits from Danbury, Essex, UK. Netherlands Journal of Geosciences 90: 271-291. Turner, C., 1970. Middle Pleistocene deposits at Marks Tey, Essex. Philosophical Transactions of the Royal Society of London, series B 257: 373-440.

Evidence of cyclic climatic changes recorded in clay mineral assemblages from a continental Paleocene-Eocene sequence, northwestern Argentina

NASA Astrophysics Data System (ADS)

Do Campo, Margarita; Bauluz, Blanca; del Papa, Cecilia; White, Timothy; Yuste, Alfonso; Mayayo, Maria Jose

2018-06-01

The continental Paleocene-Eocene sequence investigated in this study belongs to the Salta Group, deposited in an intracontinental rift, the Salta Basin (NW Argentina), that evolved from the lower Cretaceous to the middle Paleogene, and is subdivided into the Pirgua, the Balbuena and the Santa Barbara Subgroups. The Maíz Gordo Formation (200 m thick) is the middle unit of the Santa Bárbara Subgroup, deposited during late post-rift sedimentation. We studied the mineralogy of fine-grained horizons of this formation by X-ray diffraction and Scanning Electron Microscopy (SEM) in order to examine the connection between vertical changes in clay mineralogy in alluvial sediments and paleosols, and global paleoclimatic changes registered during the Paleogene. Paleosols vary from calcic vertisols in the lowermost levels, to inseptisols and gleysols in intermediate positions, to gleyed oxisols in the upper section, indicating increased chemical weathering through time. Clay mineral relative abundances vary with a general increase in kaolinite content from bottom to top. However, at one site there are significant variations in kaolinite/muscovite (Kln/Ms) that define five cycles of kaolinite abundance and Kln/Ms. that indicate cyclic patterns of paleoprecipitation and paleotemperature. These are interpreted as several short-lived hyperthermals during the Paleocene-early Eocene in the Southern Hemisphere, which correlate with well-established episodes of warmth documented from the Northern Hemisphere.

Sedimentology of the Argo and Gascoyne abyssal plains, NW Australia: Report on Ocean Drilling Program Leg 123 (Sept. 1–Nov. 1, 1988)

USGS Publications Warehouse

Thurow, Jürgen

1988-01-01

Ocean Drilling Program Leg 123 drilled two sites in the Indian Ocean in order to study the rifting and early spreading of one of the world’s oldest ocean basins.Site 765 was drilled in 5714 meters of water on the Argo Abyssal Plain northwest of Australia. The sedimentary succession records the opening of an ocean basin, from the first sediments deposited atop young oceanic crust, to the present day. The oldest sediments are microlaminated brown silty claystones, locally rich in calcareous bioclasts. Most of the sequence is dominated by turbidites (primarily calcareous) which probably originated within canyons cut into the margin of the drowned platform of the North West Shelf of Australia.Site 766 is located in 3998 meters of water, at the base of the steep western margin of the Exmouth Plateau. The oldest sediments penetrated are glauconitic, volcaniclastic, and bioclastic sandstones and siltstones, which are interbedded with inclined basaltic sills. These sediments were deposited by a prograding submarine fan system which shed shallow marine sediments westward or northwestward off of the western rim of the Exmouth Plateau. Sandstones are succeeded by silty claystones, recording gradual abandonment or redirection of the fan system. An overlying sequence of pelagic and hemipelagic clayey and zeolitic calcareous oozes and chalks is succeeded by featureless and homogeneous pelagic nannofossil oozes.

Dynamics of the formation of laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation of metals, semiconductors, and dielectrics

NASA Astrophysics Data System (ADS)

Höhm, S.; Herzlieb, M.; Rosenfeld, A.; Krüger, J.; Bonse, J.

2016-06-01

In order to address the dynamics and physical mechanisms of LIPSS formation for three different classes of materials (metals, semiconductors, and dielectrics), two-color double-fs-pulse experiments were performed on Titanium, Silicon and Fused Silica. For that purpose a Mach-Zehnder interferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences at 400 nm and 800 nm wavelength, with inter-pulse delays up to a few picoseconds. Multiple of these two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample surfaces. The fluence of each individual pulse (400 nm and 800 nm) was always kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics (periods, areas) were analyzed by scanning electron microscopy. The periods along with the LIPSS orientation allow a clear identification of the pulse which dominates the energy coupling to the material. For strong absorbing materials (Silicon, Titanium), a wavelength-dependent plasmonic mechanism can explain the delay-dependence of the LIPSS. In contrast, for dielectrics (Fused Silica) the first pulse always dominates the energy deposition and LIPSS orientation, supporting a non-plasmonic formation scenario. For all materials, these two-color experiments confirm the importance of the ultrafast energy deposition stage for LIPSS formation.

Stratigraphy and paleogeographic significance of a Late Pennsylvanian to Early Permian channeled slope sequence in the Darwin Basin, southern Darwin Hills, east-central California

USGS Publications Warehouse

Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.; Ritter, Scott M.

2015-01-01

The complex stratigraphy of late Paleozoic rocks in the southern Darwin Hills consists of regionally extensive Mississippian and Early to Middle Pennsylvanian rocks overlain by latest Pennsylvanian to Early Permian rocks, herein called the Darwin Hills sequence. Deposition of this latter sequence marked the beginning of the Darwin Basin. In Mississippian time, a carbonate platform prograded westward over slightly older slope deposits. In the Late Mississippian this platform was exposed to erosion and siliciclastic sediments were deposited. In Early to Middle Pennsylvanian time the area subsided, forming a west-facing ramp that was subjected to deformation and erosion in Middle or early Late Pennsylvanian time. Later this area was tilted westward and deep-water sediments were deposited on this slope. In latest Pennsylvanian to earliest Permian time, a major channel was cut through the older Pennsylvanian rocks and into the Upper Mississippian strata. This channel was gradually filled with increasingly finer grained, deep-water sediment as the area evolved into a basin floor by Early Permian (Sakmarian) time. Expansion of the Darwin Basin in Artinskian time led to a second phase of deposition represented by strata of the regionally extensive Darwin Canyon Formation. The geology in this small area thus documents tectonic events occurring during the early development of the Darwin Basin.

Using palynology to re-assess the Dead Sea laminated sediments - Indeed varves?

NASA Astrophysics Data System (ADS)

Bookman, Revital; Lopez-Merino, Lourdes; Belmaker, Reuven; Eshel, Amram; Epshtein Epshtein, Valentina; Leroy, Suzanne

2017-04-01

Lacustrine laminated sediments are often varves representing annual rhythmic deposition. The Dead Sea high-stand laminated sections consist of mm-scale alternating detrital and authigenic aragonite laminae. Previous studies assumed these laminae were varves; detritus deposition during the winter and aragonite in the summer. These sequences were used for varve counting and chronology, however this assumption has never been robustly validated. Here, we report an examination of the seasonal deposition of detrital and aragonite couplets from two well-known Late Holocene laminated sections at the Ze'elim fan-delta using palynology and grain-size distribution analyses. These analyses are complemented by the study of contemporary flash-flood samples and multivariate statistical analysis. Because transport affects the pollen preservation state, well-preserved (mostly) air-borne transported pollen was analysed separately from badly-preserved pollen and fungal spores, which are more indicative of water transport and reworking from soils. Our results indicate that (i) both detrital and aragonite laminae were deposited during the rainy season; (ii) aragonite laminae have significantly lower reworked pollen and fungal spore concentrations than detrital and flash-flood samples; and (iii) detrital laminae are composed of recycling of local and distal sources, with coarser particles that were initially deposited in the Dead Sea watershed and later transported via run-off to the lake. The conclusions suggest that detrital and aragonite couplets in the Dead Sea laminated sediments are most likely not varves and that the laminae deposition is related to the occurrence of flash-flood events. Consequently, at least for the Holocene sequences, laminated sediments cannot be considered as varves and Quaternary laminated sequences should be re-evaluated. The Dead Sea Basin laminated sequences (as the ICDP Dead Sea Deep Drilling Project record) should be used for the reconstruction of palaeo-flash flood records that will have a significant impact on understanding the palaeo-hydrology of the DSB and its implication to high-resolution climatic interpretation.

Magnetic and electrical characterization of nickel-rich NiFe thin films synthesized by atomic layer deposition and subsequent thermal reduction.

PubMed

Espejo, A P; Zierold, R; Gooth, J; Dendooven, J; Detavernier, C; Escrig, J; Nielsch, K

2016-08-26

Nickel-rich NiFe thin films (Ni92Fe8, Ni89Fe11 and Ni83Fe17) were prepared by combining atomic layer deposition (ALD) with a subsequent thermal reduction process. In order to obtain Ni x Fe1-x O y films, one ALD supercycle was performed according to the following sequence: m NiCp2/O3, with m = 1, 2 or 3, followed by one FeCp2/O3 cycle. The supercycle was repeated n times. The thermal reduction process in hydrogen atmosphere was investigated by in situ x-ray diffraction studies as a function of temperature. The metallic nickel iron alloy thin films were investigated and characterized with respect to crystallinity, morphology, resistivity, and magnetism. As proof-of-concept magnetic properties of an array of Ni83Fe17, close to the perfect Permalloy stoichiometry, nanotubes and an isolated tube were investigated.

Magnetic and electrical characterization of nickel-rich NiFe thin films synthesized by atomic layer deposition and subsequent thermal reduction

NASA Astrophysics Data System (ADS)

Espejo, A. P.; Zierold, R.; Gooth, J.; Dendooven, J.; Detavernier, C.; Escrig, J.; Nielsch, K.

2016-08-01

Nickel-rich NiFe thin films (Ni92Fe8, Ni89Fe11 and Ni83Fe17) were prepared by combining atomic layer deposition (ALD) with a subsequent thermal reduction process. In order to obtain Ni x Fe1-x O y films, one ALD supercycle was performed according to the following sequence: m NiCp2/O3, with m = 1, 2 or 3, followed by one FeCp2/O3 cycle. The supercycle was repeated n times. The thermal reduction process in hydrogen atmosphere was investigated by in situ x-ray diffraction studies as a function of temperature. The metallic nickel iron alloy thin films were investigated and characterized with respect to crystallinity, morphology, resistivity, and magnetism. As proof-of-concept magnetic properties of an array of Ni83Fe17, close to the perfect Permalloy stoichiometry, nanotubes and an isolated tube were investigated.

Quantitative Susceptibility Mapping as a Possible Tool to Radiographically Diagnose Sentinel Headache Associated with Intracranial Aneurysm: Case Report.

PubMed

Nakagawa, Daichi; Cushing, Cameron; Nagahama, Yasunori; Allan, Lauren; Hasan, David

2017-07-01

Sentinel headache (SH) occurs before aneurysm rupture in an estimated 15%-60% of cases of aneurysmal subarachnoid hemorrhage (aSAH). By definition, noncontrast computed tomography (CT) scan of the brain and lumbar puncture are both negative in patients presenting with SH. One of the theories explaining this phenomenon is that microhemorrhage (MH) from the aneurysm wall contribute to iron deposition in the interface between the aneurysm wall and brain parenchyma. Quantitative susceptibility mapping (QSM) is a recently introduced magnetic resonance imaging (MRI) technique that has proven capable of localizing the deposition of paramagnetic metals, particularly ferric iron. Thus, the QSM sequence may be able to detect iron deposition secondary to MH. A 76-year-old male presented with the "worst headache of my life." Noncontrast head CT scan and lumbar puncture were negative. Magnetic resonance angiography (MRA) of the brain revealed an anterior communicating artery (A-com) aneurysm measuring 7 mm with a large bleb. T1-weighted imaging (WI), T2-WI, MRA, T2 star-weighted angiography (SWAN), and QSM sequences were obtained. T2-WI, SWAN, and QSM revealed isointense, hypointense, and hyperintense signals, respectively, at the interface of the aneurysm wall and brain tissue. These findings were consistent with deposition of ferric iron at this interface. The A-com aneurysm was treated with coil embolization, and the patient exhibited no postoperative deficits. The MRI QSM sequence can localize iron deposition resulting from MH within an aneurysmal wall. This sequence may be a promising imaging tool for screening patients presenting with SH. Copyright © 2017 Elsevier Inc. All rights reserved.

Food Safety in the Age of Next Generation Sequencing, Bioinformatics, and Open Data Access.

PubMed

Taboada, Eduardo N; Graham, Morag R; Carriço, João A; Van Domselaar, Gary

2017-01-01

Public health labs and food regulatory agencies globally are embracing whole genome sequencing (WGS) as a revolutionary new method that is positioned to replace numerous existing diagnostic and microbial typing technologies with a single new target: the microbial draft genome. The ability to cheaply generate large amounts of microbial genome sequence data, combined with emerging policies of food regulatory and public health institutions making their microbial sequences increasingly available and public, has served to open up the field to the general scientific community. This open data access policy shift has resulted in a proliferation of data being deposited into sequence repositories and of novel bioinformatics software designed to analyze these vast datasets. There also has been a more recent drive for improved data sharing to achieve more effective global surveillance, public health and food safety. Such developments have heightened the need for enhanced analytical systems in order to process and interpret this new type of data in a timely fashion. In this review we outline the emergence of genomics, bioinformatics and open data in the context of food safety. We also survey major efforts to translate genomics and bioinformatics technologies out of the research lab and into routine use in modern food safety labs. We conclude by discussing the challenges and opportunities that remain, including those expected to play a major role in the future of food safety science.

Sequence stratigraphy of the subaqueous Changjiang (Yangtze River) delta since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Xu, Taoyu; Wang, Guoqing; Shi, Xuefa; Wang, Xin; Yao, Zhengquan; Yang, Gang; Fang, Xisheng; Qiao, Shuqing; Liu, Shengfa; Wang, Xuchen; Zhao, Quanhong

2016-01-01

This study focuses on sedimentary research at the subaqueous Changjiang (Yangtze River) delta, based on five high-resolution seismic profiles and seven borehole cores with accurate AMS 14C datings. Three distinct seismic units were identified from the seismic profiles according to seismic reflection characteristics, and five sedimentary facies were recognized from borehole cores. These facies constituted a fining upward sedimentary sequence in relation to postglacial sea-level transgression. Three sequence surfaces (sequence boundary (SB), transgressive surface (TS), and maximum flooding surface (MFS)) demarcate the boundaries between early transgressive system tract (E-TST), late transgressive system tract (L-TST), early highstand system tract (E-HST) and late highstand system tract (L-HST), which constitute the sixth order sequence. These system tracts were developed coevally with postglacial sea-level rise. E-TST (~ 19-12 ka BP) corresponds to an incised-valley infilling in the early stages of postglacial transgression whereas L-TST (~ 12-7.5 ka BP) was formed during the last stage of postglacial transgression. The progradational structure of L-TST reflected in seismic profiles is possibly related to the intensification of the East Asian summer monsoon. E-HST (~ 7.5-2 ka BP) was deposited in response to the highstand after maximum postglacial transgression was reached, while L-HST (~ 2 ka BP-present) was initiated by accelerated progradation of the Changjiang delta.

The stratigraphy of the southern Pab Range, Pakistan

NASA Astrophysics Data System (ADS)

White, H. J.

The Cretaceous strata exposed in the southern Pab Range, southeast Baluchistan, Pakistan is investigated. It records the precollision deposition history of the Indo-Pakistani continental shelf. The strata comprise two depositional successions, namely, The Early to Late Cretaceous Sembar-Goru-Parh sequence and the Maestrichtian Mughal Kot-Pab sequence. The former began with deposition of black shales on the continental slope (Sembar Formation), succeeded by calcareous shale, marl and micstone of outer shelf origin (Goru Formation), and ended with inner shelf platform carbonates (Parh Limestone). These deep to shallow water lithofacies prograted westward over the continental shelf of the north-advancing Subcontinent. The Mughal Kot-Pab propagation contains the first significant influx of terrigenous sand reaching the western portion of the continental shelf. Deposition environments in the Mughal Kot Formation include inner shelf, prodelta, delta front and distributary channel. A thick succession of shoreface cycles comprises the Pab sandstone.

Patterns of maternal yolk hormones in eastern screech owl eggs (Megascops asio)

USGS Publications Warehouse

Hahn, D. Caldwell

2011-01-01

Owl clutches typically hatch asynchronously, and brood size hierarchies develop. In this study, we describe intra-clutch variation of testosterone, androstenedione, estradiol, and corticosterone in Eastern screech owl egg yolks. In order to assess whether these hormones may have originated in the follicle, we also characterize variation of testosterone, androstenedione, and corticosterone within the exterior, intermediate, and interior regions of the yolk. Concentrations of testosterone and androstenedione were distributed relatively evenly across egg lay order with the exception of first-laid eggs that had significantly lower concentrations of both androgens than eggs later in the laying sequence. Corticosterone and estradiol did not vary with laying order. Our results suggest that when food is abundant, yolk hormones are deposited in patterns that minimize sibling differences except to reduce dominance by the first-hatching chick. Testosterone and androstenedione concentrations varied throughout the yolk, while corticosterone was evenly distributed throughout the yolk. This supports a follicular origin for both yolk androgens, and an adrenal origin for yolk corticosterone.

Detection of pathogenic Leptospira species associated with phyllostomid bats (Mammalia: Chiroptera) from Veracruz, Mexico.

PubMed

Ballados-González, G G; Sánchez-Montes, S; Romero-Salas, D; Colunga Salas, P; Gutiérrez-Molina, R; León-Paniagua, L; Becker, I; Méndez-Ojeda, M L; Barrientos-Salcedo, C; Serna-Lagunes, R; Cruz-Romero, A

2018-06-01

The genus Leptospira encompass 22 species of spirochaetes, with ten pathogenic species that have been recorded in more than 160 mammals worldwide. In the last two decades, the numbers of records of these agents associated with bats have increased exponentially, particularly in America. Although order Chiroptera represents the second most diverse order of mammals in Mexico, and leptospirosis represents a human and veterinary problem in the country, few studies have been conducted to identify potential wildlife reservoirs. The aim of this study was to detect the presence and diversity of Leptospira sp. in communities of bats in an endemic state of leptospirosis in Mexico. During January to September 2016, 81 bats of ten species from three localities of Veracruz, Mexico, were collected with mist nets. Kidney samples were obtained from all specimens. For the detection of Leptospira sp., we amplified several genes using specific primers. Amplicons of the expected size were submitted to sequencing, and sequences recovered were compared with those of reference deposited in GenBank using the BLAST tool. To identify their phylogenetic position, we realized a reconstruction using maximum-likelihood (ML) method. Twenty-five samples from three bat species (Artibeus lituratus, Choeroniscus godmani and Desmodus rotundus) showed the presence of Leptospira DNA. Sequences recovered were close to Leptospira noguchii, Leptospira weilii and Leptospira interrogans. Our results include the first record of Leptospira in bats from Mexico and exhibit a high diversity of these pathogens circulating in the state. Due to the finding of a large number of positive wild animals, it is necessary to implement a surveillance system in populations of the positive bats as well as in related species, in order to understand their role as carriers of this bacterial genus. © 2018 Blackwell Verlag GmbH.

The Orosirian-Statherian banded iron formation-bearing sequences of the southern border of the Espinhaço Range, Southeast Brazil

NASA Astrophysics Data System (ADS)

Rolim, Vassily Khoury; Rosière, Carlos A.; Santos, João Orestes Schneider; McNaughton, Neal J.

2016-01-01

The Serra da Serpentina and the Serra de São José groups are two distinct banded iron formation-bearing metasedimentary sequences along the eastern border of the southern Espinhaço Range that were deposited on the boundary between the Orosirian and Statherian periods. The Serra da Serpentina Group (SSG) has an Orosirian maximum depositional age (youngest detrital zircon grain age = 1990 ± 16 Ma) and consists of fine clastic metasediments at the base and chemical sediments, including banded iron formations (BIFs), on the top, corresponding to the Meloso and Serra do Sapo formations, respectively, and correlating with the pre-Espinhaço Costa Sena Group. The SSG represents sedimentary deposition on an epicontinental-epeiric, slow downwarping sag basin with little tectonic activity. The younger Serra de São José Group (SJG) is separated from the older SSG by an erosional unconformity and was deposited in a tectonically active continental rift-basin in the early stages of the opening of the Espinhaço Trough. The Serra do São José sediments stretch along the north-south axis of the rift and comprise a complete cycle of transgressive sedimentary deposits, which were subdivided, from base to top, into the Lapão, Itapanhoacanga, Jacém and Canjica formations. The Itapanhoacanga Formation has a maximum depositional age of 1666 ± 32 Ma (Statherian), which coincides with the maximum depositional age (i.e., 1683 ± 11 Ma) of the São João da Chapada Formation, one of the Espinhaço Supergroup's basal units. The Serra de São José Rift and the Espinhaço Rift likely represent the same system, with basal units that are facies variations of the same sequence. The supracrustal rocks have undergone two stages of deformation during the west-verging Brasiliano orogeny that affected the eastern margin of the São Francisco Craton and generated a regional-scale, foreland N-S trending fold-thrust belt, which partially involved the crystalline basement. Thrust faults have segmented the terrain into a large number of tectonic blocks, where the stratigraphic sequence was nevertheless well preserved.

Complete Genome Sequences of Two Vesicular Stomatitis Virus Isolates Collected in Mexico

PubMed Central

Isa, Pavel; Pauszek, Steven J.; Rodriguez, Luis L.

2017-01-01

ABSTRACT We report two full-genome sequences of vesicular stomatitis New Jersey virus (VSNJV) obtained by Illumina next-generation sequencing of RNA isolated from epithelial suspensions of cattle naturally infected in Mexico. These genomes represent the first full-genome sequences of vesicular stomatitis New Jersey viruses circulating in Mexico deposited in the GenBank database. PMID:28912331

The carbohydrate-binding module (CBM)-like sequence is crucial for rice CWA1/BC1 function in proper assembly of secondary cell wall materials.

PubMed

Sato, Kanna; Ito, Sachiko; Fujii, Takeo; Suzuki, Ryu; Takenouchi, Sachi; Nakaba, Satoshi; Funada, Ryo; Sano, Yuzou; Kajita, Shinya; Kitano, Hidemi; Katayama, Yoshihiro

2010-11-01

We recently reported that the cwa1 mutation disturbed the deposition and assembly of secondary cell wall materials in the cortical fiber of rice internodes. Genetic analysis revealed that cwa1 is allelic to bc1, which encodes glycosylphosphatidylinositol (GPI)-anchored COBRA-like protein with the highest homology to Arabidopsis COBRA-like 4 (COBL4) and maize Brittle Stalk 2 (Bk2). Our results suggested that CWA1/BC1 plays a role in assembling secondary cell wall materials at appropriate sites, enabling synthesis of highly ordered secondary cell wall structure with solid and flexible internodes in rice. The N-terminal amino acid sequence of CWA1/BC1, as well as its orthologs (COBL4, Bk2) and other BC1-like proteins in rice, shows weak similarity to a family II carbohydrate-binding module (CBM2) of several bacterial cellulases. To investigate the importance of the CBM-like sequence of CWA1/BC1 in the assembly of secondary cell wall materials, Trp residues in the CBM-like sequence, which is important for carbohydrate binding, were substituted for Val residues and introduced into the cwa1 mutant. CWA1/BC1 with the mutated sequence did not complement the abnormal secondary cell walls seen in the cwa1 mutant, indicating that the CBM-like sequence is essential for the proper function of CWA1/BC1, including assembly of secondary cell wall materials.

Provenance and sequence architecture of the Middle-Late Eocene Gehannam and Birket Qarun formations at Wadi Al Hitan, Fayum Province, Egypt

NASA Astrophysics Data System (ADS)

Anan, Tarek; El Shahat, Adam

2014-12-01

The Middle-Upper Eocene Gehannam and Birket Qarun formations at Wadi Al Hitan (Valley of Whales) in Fayum Province of Egypt are dominated by marine siliciclastic sediments. Sedimentation took place in synclinal basins that were inherited from the Late Cretaceous tectonism. The siliciclastic sediments accumulated in low energy open shallow marine shelf. Most of the siliciclastics are heavily bioturbated by Thalassinoides. The abundance of unstable and moderately stable heavy minerals suggests that the Middle-Upper Eocene clastics were largely derived from the weathered regolith of the exhumed basement rocks of the Red Sea mountains. The ultrastable heavies were mainly recycled from positive landmass that bound the Eocene basins. Two sequence boundaries were observed in the studied succession. The first boundary lies within a rhizolith bearing-sandstone unit that occurs at the boundary between the Gehannam and Birket Qarun formations. The second sequence boundary occurs within the upper part of the Birket Qarun Formation, in a shale horizon bioturbated by Thalassinoides. Three 3rd order depositional sequences were recognized. These sequences may be formed due to tectonic activity that started in the Late Cretaceous and may be rejuvenated again during the Eocene time. Also emergence activities that were active during the Eocene led to the formation of the picked sequences by changing relative sea level. The recorded systems tracts are transgressive systems tract (TST), highstand systems tract (HST), and falling-stage systems tract (FSST).

A Quaternary paleolake in a sinkhole at Cassis (SE France) : a geomorphology and geophysical study

NASA Astrophysics Data System (ADS)

Romey, C.; Rochette, P.; Vella, C.; Arfib, B.; Champollion, C.; Dussouillez, P.; Hermitte, D.; Parisot, J.-C.

2012-04-01

The Lower Provence and the Massif des Calanques, near Marseille, are a key area in understanding the mechanisms of evolution of the Mediterranean climate and the study of human impact on the local environment during the Quaternary. However, a continuous continental record of paleoenvironment in coastal Provence was not previously available. Looking for such a record, we discovered in a coastal alluvial plain a small paleolake filling a sinkhole that occurred in a marl sequence topping pure limestones at an altitude of 80 m, and a distance to the sea of 2 km. The sinkhole is close to the outlet of a small catchment area of about 8 km2. Limestone is massive but much fractured and therefore suitable for the development of karst. The drilling sedimentary sequence of 50 meters is mainly resulting from the weathering of Cretaceous marls. It consists of 5 meters of oxidized brown clay deposit which covers 45 meters of laminated lacustrine gray clay with sandy past. Cretaceous marls are at the base of the sequence. The presence of marls pebbles in the last meters of the sequence reflects the collapse of the sinkhole. The lacustrine clay was probably deposed during stages isotope 2 to 4 (48 ± 3 ka C14 date at 23 meters depth), whereas brown clay deposit was interpreted as Holocene paleosol. Combination of surface observation, drilling and geophysical studies (gravimetry and Electrical Resistivity Tomography) allows to constraint the geometry of the paleo-polje that formed during glacial period. Lake diameter was likely of the order of 200 m. It evolved from a deep lake to a swamp (probably Holocene, dating in progress) and it was drained in roman times for agriculture. Locally, this discovery has implications for the understanding of karst processes and water resources. The relationship between the sinkhole, rooted at circa 100 m below surface according to gravimetric modeling and the underground karstic river of Bestouan is strongly suggested by underwater exploration and hydrogeologic investigations.

Smart biomaterials: Surfaces functionalized with proteolytically stable osteoblast-adhesive peptides.

PubMed

Zamuner, Annj; Brun, Paola; Scorzeto, Michele; Sica, Giuseppe; Castagliuolo, Ignazio; Dettin, Monica

2017-09-01

Engineered scaffolds for bone tissue regeneration are designed to promote cell adhesion, growth, proliferation and differentiation. Recently, covalent and selective functionalization of glass and titanium surfaces with an adhesive peptide (HVP) mapped on [351-359] sequence of human Vitronectin allowed to selectively increase osteoblast attachment and adhesion strength in in vitro assays, and to promote osseointegration in in vivo studies. For the first time to our knowledge, in this study we investigated the resistance of adhesion sequences to proteolytic digestion: HVP was completely cleaved after 5 h. In order to overcome the enzymatic degradation of the native peptide under physiological conditions we synthetized three analogues of HVP sequence. A retro-inverted peptide D-2HVP, composed of D amino acids, was completely stable in serum-containing medium. In addition, glass surfaces functionalized with D-2HVP increased human osteoblast adhesion as compared to the native peptide and maintained deposition of calcium. Interestingly, D-2HVP increased expression of IBSP, VTN and SPP1 genes as compared to HVP functionalized surfaces. Total internal reflection fluorescence microscope analysis showed cells with numerous filopodia spread on D-2HVP-functionalized surfaces. Therefore, the D-2HVP sequence is proposed as new osteoblast adhesive peptide with increased bioactivity and high proteolytic resistance.

Thermophysical Properties of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS

NASA Technical Reports Server (NTRS)

Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.

2003-01-01

The presence of a thick sequence of horizontal layers of ice-rich material at Mars north pole, dissected by troughs and eroding at its margins, is undoubtedly telling us something about the evolution of Mars climate [1,2] we just don t know what yet. The North Polar Layered Deposits (NPLD) most likely formed as astronomically driven climate variations led to the deposition of conformable, areally extensive layers of ice and dust over the polar region. More recently, the balance seems to have fundamentally shifted to net erosion, as evidenced by the many troughs within the NPLD and the steep, arcuate scarps present near its margins, both of which expose layering. We defined a number of Regions of Interest ROI) for THEMIS to target as part of the Mars Odyssey Participating Scientist program. We use these THEMIS data in order to understand the morphology and color/thermal properties of the NPLD and related materials over relevant (i.e., m to km) spatial scales. We have assembled color mosaics of our ROIs in order to map the distribution of ices, the different layered units, dark material, and underlying basement. The color information from THEMIS is crucial for distinguishing these different units which are less distinct on Mars Orbiter Camera images. We wish to understand the nature of the marginal scarps and their relationship to the dark material. Our next, more ambitious goal is to derive the thermophysical properties of the different geologic materials using THEMIS and Mars Global Surveyor Thermal Emission Spectrometer TES) data.

Linking Late Cretaceous to Eocene Tectonostratigraphy of the San Jacinto Fold Belt of NW Colombia With Caribbean Plateau Collision and Flat Subduction

NASA Astrophysics Data System (ADS)

Mora, J. Alejandro; Oncken, Onno; Le Breton, Eline; Ibánez-Mejia, Mauricio; Faccenna, Claudio; Veloza, Gabriel; Vélez, Vickye; de Freitas, Mario; Mesa, Andrés.

2017-11-01

Collision with and subduction of an oceanic plateau is a rare and transient process that usually leaves an indirect imprint only. Through a tectonostratigraphic analysis of pre-Oligocene sequences in the San Jacinto fold belt of northern Colombia, we show the Late Cretaceous to Eocene tectonic evolution of northwestern South America upon collision and ongoing subduction with the Caribbean Plate. We linked the deposition of four fore-arc basin sequences to specific collision/subduction stages and related their bounding unconformities to major tectonic episodes. The Upper Cretaceous Cansona sequence was deposited in a marine fore-arc setting in which the Caribbean Plate was being subducted beneath northwestern South America, producing contemporaneous magmatism in the present-day Lower Magdalena Valley basin. Coeval strike-slip faulting by the Romeral wrench fault system accommodated right-lateral displacement due to oblique convergence. In latest Cretaceous times, the Caribbean Plateau collided with South America marking a change to more terrestrially influenced marine environments characteristic of the upper Paleocene to lower Eocene San Cayetano sequence, also deposited in a fore-arc setting with an active volcanic arc. A lower to middle Eocene angular unconformity at the top of the San Cayetano sequence, the termination of the activity of the Romeral Fault System, and the cessation of arc magmatism are interpreted to indicate the onset of low-angle subduction of the thick and buoyant Caribbean Plateau beneath South America, which occurred between 56 and 43 Ma. Flat subduction of the plateau has continued to the present and would be the main cause of amagmatic post-Eocene deposition.

Stratigraphy and depositional environments of Fox Hills Formation in Williston basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, D.J.

The Fox Hills Formation (Maestrichtian), representing part of a regressive wedge deposited during the withdrawal of the sea from the Western Interior at the close of the Cretaceous, consists of marginal marine strata transitional between the offshore deposits of the underlying Pierre Shale and the terrestrial deltaic and coastal deposits of the overlying Hell Creek Formation. An investigation of outcrops of the Fox Hills Formation along the western and southern flanks of the Williston basin and study of over 300 oil and gas well logs from the central part of the basin indicate that the formation can be divided bothmore » stratigraphically and areally. Stratigraphically, the Fox Hills can be divided into lower and upper sequences; the lower includes the Trail City and Timber Lake Members, and the upper sequence includes the Colgate Member in the west and the Iron Lightning and Linton Members in the east. Areally, the formation can be divided into a northeastern and western part, where the strata are 30-45 m thick and are dominated by the lower sequence, and into a southeastern area where both the lower and upper sequences are well developed in a section 80-130 m thick. Typically, the lower Fox Hills consists of upward-coarsening shoreface or delta-front sequences containing hummocky bedding and a limited suite of trace fossils, most notably Ophiomorpha. In the southeast, however, these strata are dominated by bar complexes, oriented northeast-southwest, composed of cross-bedded medium to very fine-grained sand with abundant trace and body fossils. The upper Fox Hills represents a variety of shoreface, deltaic, and channel environments. The strata of the Fox Hills Formation exhibit facies similar to those reported for Upper Cretaceous gas reservoirs in the northern Great Plains.« less

Low-Temperature Molecular Layer Deposition Using Monofunctional Aromatic Precursors and Ozone-Based Ring-Opening Reactions.

PubMed

Svärd, Laura; Putkonen, Matti; Kenttä, Eija; Sajavaara, Timo; Krahl, Fabian; Karppinen, Maarit; Van de Kerckhove, Kevin; Detavernier, Christophe; Simell, Pekka

2017-09-26

Molecular layer deposition (MLD) is an increasingly used deposition technique for producing thin coatings consisting of purely organic or hybrid inorganic-organic materials. When organic materials are prepared, low deposition temperatures are often required to avoid decomposition, thus causing problems with low vapor pressure precursors. Monofunctional compounds have higher vapor pressures than traditional bi- or trifunctional MLD precursors, but do not offer the required functional groups for continuing the MLD growth in subsequent deposition cycles. In this study, we have used high vapor pressure monofunctional aromatic precursors in combination with ozone-triggered ring-opening reactions to achieve sustained sequential growth. MLD depositions were carried out by using three different aromatic precursors in an ABC sequence, namely with TMA + phenol + O 3 , TMA + 3-(trifluoromethyl)phenol + O 3 , and TMA + 2-fluoro-4-(trifluoromethyl)benzaldehyde + O 3 . Furthermore, the effect of hydrogen peroxide as a fourth step was evaluated for all studied processes resulting in a four-precursor ABCD sequence. According to the characterization results by ellipsometry, infrared spectroscopy, and X-ray reflectivity, self-limiting MLD processes could be obtained between 75 and 150 °C with each of the three aromatic precursors. In all cases, the GPC (growth per cycle) decreased with increasing temperature. In situ infrared spectroscopy indicated that ring-opening reactions occurred in each ABC sequence. Compositional analysis using time-of-flight elastic recoil detection indicated that fluorine could be incorporated into the film when 3-(trifluoromethyl)phenol and 2-fluoro-4-(trifluoromethyl)benzaldehyde were used as precursors.

Sedimentology of the lower part of the Upper Triassic Chinle Formation and its relationship to uranium deposits, White Canyon area, southeastern Utah

USGS Publications Warehouse

Dubiel, Russell F.

1983-01-01

Closely spaced measured stratigraphic sections of the lower part of the Late Triassic Chinle Formation in the White Canyon area of southeastern Utah depict a fluvial-deltaic-lacustrine depositional sequence that hosts uranium deposits in basal fluvial sandstones. The basal Shinarump Member consists of predominantly trough-crossbedded, coarse-grained sandstone and minor gray, carbonaceous mudstone and is interpreted as a valley-fill sequence overlain by deposits of a braided stream system. The overlying Monitor Butte Member is composed of cyclic- and foreset-bedded siltstone, sandstone, and mudstone and is interpreted as a succession of low-energy fluvial, deltaic and orqanicrich, lacustrine-marsh sediments. The overlying Moss Back Member is composed of a laterally extensive, coarse- to medium-grained, conglomeratic sandstone and is interpreted as a braided-stream system that flowed north to northwest. The entire sequence was deposited in response to changes in local base level associated with a large lake that lay to the west. Isopachs of lithofacies indicate distinct lacustrine basins and a correspondence between these facies and modern structural synclines. Facies changes and coincidence of isopach thicks suggest that structural synclines were active in the Late Triassic and influenced the pattern of sediment distribution within the basins. Uranium mineralization appears to be related to certain low-energy depositional environments in that uranium is localized in fluvial sandstones that lie beneath organic-rich lacustrine-marsh mudstones and carbonaceous delta-front sediments. The reducing environment preserved in these facies may have played an important role in the localization of uranium.

Upper Cretaceous ramp limestones from the Sorrento Peninsula (southern Apennines, Italy): micro- and macrofossil associations and their significance in the depositional sequences

NASA Astrophysics Data System (ADS)

Carannante, G.; Ruberti, D.; Sirna, M.

2000-04-01

The Upper Cretaceous limestones of the Sorrento Peninsula are primarily characterized by wackestone/packstone with benthic foraminifers, thaumatoporellaceans and Aeolisaccus sp. and by rudist floatstones. Rudists in growth position are rare; most of them appear toppled and locally oriented but not reworked. In some cases they form small bouquets no more than 30 cm thick. The successions analyzed in the Sorrento Peninsula encompass a variety of facies representative of inner shelf environments in a ramp-like depositional setting. On the basis of lithologic and sedimentologic characteristics and on a qualitative analysis of the biofacies, three major facies associations have been recognized corresponding to: (a) intertidal silty-sand flats and shallow lagoons; (b) subtidal mobile foraminiferal sand sheets; (c) subtidal rudist dwelt sand plain. In the lower part of the successions periodic (more or less prolonged) emersions (subaqueous with fresh/brackish waters or subaerial exposure) are documented. The upper part of each succession lacks any emersion evidence; submarine exposure surfaces are testified by firmground-related features. The periodic influence of high-energy regimes (some storm-related events) is documented by wave- and cross-laminations, HCS and the lack of fine sediments. Lithofacies are arranged in depositional cycles that may correspond to individual beds. The boundaries of the depositional cycles show evidence of subaerial or submarine exposures. The nature and position of these discontinuity surfaces in the successions provide an important clue to interpretation in terms of both depositional environment and vertical evolution. The increase in thickness of the depositional cycles and the gradual change from peritidal/shallow-subtidal cycles to dominantly subtidal cycles, document an increase in the amount of accommodation space which resulted from a long-term rise in relative sea-level. A detailed study of benthic associations (micro- and macrofauna) has been carried out in order to identify accurately further signs of periodicity contained within the successions as a whole. These Upper Cretaceous limestones are abundantly fossiliferous with only a moderately diverse fauna. There are no significant differences in terms of species, the assemblages simply reflecting differences in abundance of the same species. Taphonomic studies of rudist-rich beds permit seven major shell-bed types to be distinguished. Six main foraminiferal assemblages have been detected, and the distribution and relative abundance of the species have been examined within the environments inferred through facies analysis. The taphonomic data and the foraminiferal assemblage abundance and diversity, have been compared with lithologic and sedimentologic data in order to elucidate their distribution within depositional cycles and throughout the successions. The successions show little up-section changes in lithology and in taxonomic composition of the foraminiferal assemblages. It is therefore difficult to establish a paleoenvironmental trend independent of the rudist shell concentrations, which do change up-section. We noticed an overall increase in thickness and abundance of the shell beds and a shift in types of shell concentration and in taxonomic composition. These characteristics, associated with the upward disappearance of emersion surfaces, the higher frequency of storm and/or wave intercalations, the increase in thickness of the depositional sequences and the gradual change from peritidal/shallow-subtidal cycles to dominantly subtidal cycles, document a general deepening-upward trend. More open water conditions with a depth between fairweather and storm wave-base became established as a result of relative sea-level rise and to a consequent increase in the available accommodation space.

Tectono-sedimentary constraints to the Oligocene-to-Miocene evolution of the Peloritani thrust belt (NE Sicily)

NASA Astrophysics Data System (ADS)

Giunta, G.; Nigro, F.

1999-12-01

The Peloritani thrust belt belongs to the southern sector of the Calabrian Arc and is formed by a set of south-verging tectonic units, including crystalline basement and sedimentary cover (from the top: Aspromonte U.; Mela U.; Mandanici U.; Fondachelli U.; Longi-Taormina U.), piled up starting from Late Oligocene. At least two main terrigenous clastic formations lie with complicated relationships on top of the previous units: the Frazzanò Fm (Oligocene) and the Stilo-Capo d'Orlando Fm (Late Oligocene?-Early Miocene), as syn-to-post-tectonic deposits. These clastic deposits have different characteristics, in space and time, representing or flysch-like sequences involved in several thrust events (Frazzanò Fm) or molassic-like sequences (Stilo-Capo d'Orlando Fm), which unconformably overlie the tectonic units. In the present paper we describe a kinematic model of the progressive foreland migration of the Peloritani thrust belt, starting from Oligocene, carrying piggy-back basins and incorporating foredeep deposits, recognised in the Frazzanò-Stilo-Capo d'Orlando terrigenous successions. In general, the facies and structural observations on the overall Oligo-Miocene clastic sequences, outcropping in the Western Peloritani Mts, indicate: (a) the distal character of the Frazzanò Fm; (b) a complex group of terrigenous facies of the Stilo-Capo d'Orlando Fm, with lateral-to-vertical organisation, characterised by a distal-to-proximal-to-distal facies trend; (c) facies analogies of the basal portions of the Stilo-Capo d'Orlando Fm with the Frazzanò Fm; (d) the involvement of the Frazzanò Fm in lowermost and more external thrusting, and of the basal (Late Oligocene?) distal Stilo-Capo d'Orlando facies in the higher and inner thrusting during the early stages of deformation; (e) the involvement of the proximal Stilo-Capo d'Orlando facies in the tectonic edifice during the Early Miocene deformation; (f) the generally unconformable stratigraphical contacts of the higher proximal-to-distal (Early Miocene) Stilo-Capo d'Orlando facies on the constructing mobile belt; and (g) the presence of various thrust-faults, distinguished in a sequential order. The collected data allow us to hypothesise that the Oligo-Miocene tectono-sedimentary history was characterised by a foredeep with a deforming internal flank, probably lying in onlap on the constructing tectonic edifice (Frazzanò-lower Stilo-Capo d'Orlando Fms), and then deformed and covered by a piggy-back like sequence (middle-upper Stilo-Capo d'Orlando Fm), which was subsequently also deformed. The tectono-sedimentary evolution of the Peloritani belt has been probably developed through a progressive migration towards the foreland of a foredeep-compressional front couple and the chain body. The thrust stack progressively incorporates terrigenous foredeep deposits and in turn carried piggy-back basins.

Mass Dependent Fractionation of Hg Isotopes in Source Rocks, Mineral Deposits and Spring Waters of the California Coast Ranges, USA

NASA Astrophysics Data System (ADS)

Smith, C. N.; Kesler, S. E.; Blum, J. D.; Rytuba, J. J.

2007-12-01

We present here the first study of the isotopic composition of Hg in rocks, ore deposits, and active hydrothermal systems from the California Coast Ranges, one of Earth's largest Hg-depositing systems. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of Hg deposits, hot-spring deposits that form at shallow depths (<300 m) and silica-carbonate deposits that extend to greater depths (200 to 1000 m), as well as active springs and geothermal systems that release Hg to the present surface. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of Hg than volcanic rocks of the Clear Lake Volcanic Field. Mean Hg isotope compositions for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate Hg deposits have similar average isotopic compositions that are indistinguishable from averages for the three rock units, although δ202Hg values for the Hg deposits have a greater variance than the country rocks. Precipitates from dilute spring and saline thermal waters in the area have similarly large variance and a mean δ202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate there is little or no isotopic fractionation during release of Hg from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of Hg in deposits, especially in their uppermost parts. Boiling of hydrothermal fluids is likely the most important process causing of the observed Hg isotope fractionation. This should result in the release of Hg with low δ202Hg values into the atmosphere from the top of these hydrothermal systems and a consequent enrichment in heavy Hg isotopes in the upper crust through time.

Tracing Marine Cryptotephras in the North Atlantic during the Last Glacial Period

NASA Astrophysics Data System (ADS)

Abbott, Peter; Davies, Siwan; Griggs, Adam; Bourne, Anna

2017-04-01

Tephrochronology is a powerful technique that can be utilised for the independent correlation and synchronisation of disparate palaeoclimatic records from different depositional environments. There is a high potential to utilise this technique to integrate ice, marine and terrestrial records to study climatic phasing within the North Atlantic region due to the high eruptive frequency of Icelandic volcanic systems. However, until now North Atlantic marine records have been relatively understudied. Here we report on investigations to define a tephra framework integrating new studies of cryptotephra horizons within a wide network of North Atlantic marine cores with horizons identified in prior work. This framework has the potential to underpin the correlation of the marine records to the Greenland ice-core records and European terrestrial sequences. Tephrochronological investigations were conducted on 13 marine sequences from a range of locations and depositional settings using cryptotephra extraction techniques, including density and magnetic separation, to gain high resolution glass shard concentration profiles and rigorous single-shard major element geochemical analysis to characterise identified deposits. Cryptotephras with an Icelandic source were identified in many records and displayed diversity in shard concentration profiles and the geochemical homo/heterogeneity of shards within the deposits. These differences reflect spatial and temporal variability in the operation of a range of transport processes, e.g. airfall, sea-ice and iceberg rafting, and post-depositional processes, e.g. bioturbation and secondary redeposition. The operation of these processes within the marine environment can potentially impart a temporal delay on tephra deposition and hamper the placement of the isochron, therefore, it is crucial to assess their influence. To aid this assessment a range of deposit types with common transport and depositional histories have been defined. Spatial patterns in the occurrence of these deposit types have been detected, the dominant controls at different sites explored and key regions of the North Atlantic with a greater likelihood for preserving isochronous deposits identified. Overall, these investigations have allowed a framework of isochronous marine cryptotephras to be defined for the last glacial period. The most widespread deposit is the rhyolitic phase of North Atlantic Ash Zone II, identified in 9 of the marine sequences and providing a direct tie-line to the Greenland ice-cores records. The framework is dominated by horizons with a basaltic composition, predominantly sourced from the Icelandic Grímsvötn volcanic system but horizons with Katla, Hekla, Kverkfjöll, Veidivötn and Vestmannaeyjar like compositions have also been isolated. Correlations to horizons in the Greenland ice-core tephra framework are being explored, however, this is a challenging process due to the large number of horizons with similar geochemical signatures in the records and the difference in temporal resolution and stratigraphic control between the ice and marine sequences.

The Miocene Topanga Group of Southern California - A 100-Year History of Changes in Stratigraphic Nomenclature

USGS Publications Warehouse

Campbell, Russell H.; McCulloh, Thane H.; Vedder, John G.

2007-01-01

A review of selected literature summarizes the origin and chronology of changes in usage of 'Topanga' in the Miocene stratigraphic nomenclature of the Los Angeles Basin and adjacent areas in southern California. The review was done to summarize and reconcile some differences in Miocene stratigraphic nomenclature as applied to geologic map compilations of the Santa Ana (Morton, 2004), San Bernardino (Morton and Miller, 2003), Long Beach (Saucedo and others, 2003) and Los Angeles (Yerkes and Campbell, 2005) 30' x 60' quadrangles, all of which are products of the cooperative (California Geological Survey-U.S. Geological Survey) Southern California Areal Mapping Project (SCAMP). The deposition of the Topanga Group spans about 6 my (from as old as about 18 ma to as young as about 12 ma), and the sequence of included strata records changes in provenance and depositional environments that are contemporaneous with part of a major Miocene tectonic episode in southern California -- the 'basin-inception phase' in the evolution of the Neogene Los Angeles basin (Yerkes and others, 1965). The area of Topanga deposition extends to the southern, eastern, northern, and northwestern sides of the Los Angeles basin, as well as the southern part of the eastern Ventura Basin. Topanga beds are inferred to underlie the thick upper Miocene and Pliocene deposits of the central Los Angeles Basin and the southern part of the eastern Ventura Basin; however, they have been reached by drilling only in marginal areas, where the overlying deposits are relatively thin. Post-Topanga strata were deposited in more-restricted areas of rapid subsidence. Selected papers are summarized as they relate to the Topanga nomenclature, and are presented in chronological order.

Late Pleistocene (MIS5-3) environmental reconstruction from north-eastern Iberia through microvertebrate and palaeobotanical records

NASA Astrophysics Data System (ADS)

Allue, Ethel; Bennàssar, Maria; Biltekin, Demet; Blain, Hugues-Alexandre; Burjachs, Francesc; Euba, Itxaso; Expósito, Isabel; Fernández-García, Mónica; López-García, Juan Manuel

2014-05-01

The aim of this work is to analyze the environmental changes during the Late Pleistocene on the basis of a multi-approach study based on natural and archaeological deposits from NE Iberian Peninsula. The focussed area, although having a small extension (some 32.000 square kilometres), covers a large range of ecosystems and bioclimatic conditions from the Mediterranean seashore to the summit of the Pyrenean mountain ranges (up to 2000 masl). This synthetical approach includes materials from various contexts including 10 archaeological deposits and a single natural deposit. In this work, plant (pollen and charcoals) and animal (small mammals, amphibians and reptiles) records are being analysed and compared in order to present an overview of the environmental changes occurred from the MIS5 to MIS3. On the first hand, we are using the small-vertebrate records recovered from archaeological deposits. These proxies are mainly the product of pellets from birds of prey and are key ecological markers. On the second hand, palaeobotanical evidences, pollen and charcoal, have different formation processes. Charcoal remains are mostly from archaeological deposits and are due to human activities related to fire showing evidences of the local vegetation. Pollen evidences from archaeological and natural contexts are deposited through natural processes (wind, insects, etc.) and show regional scale vegetation record. Results indicate the presence of temperate elements during all these periods (especially at the seashore area), with a more important representation and extension southwards or changes in altitude from taxa with eurosiberian affinities during coldest periods. Forest coverage, plant and vertebrate distribution along the territory point out a mosaic landscape formed by open areas and forests. These landscapes have probably a more or less Mediterranean or Eurosiberian character depending on the climatic moment and their location with variations along the sequence.

The giant Carlin gold province: A protracted interplay of orogenic, basinal, and hydrothermal processes above a lithospheric boundary

USGS Publications Warehouse

Emsbo, P.; Groves, D.I.; Hofstra, A.H.; Bierlein, F.P.

2006-01-01

Northern Nevada hosts the only province that contains multiple world-class Carlin-type gold deposits. The first-order control on the uniqueness of this province is its anomalous far back-arc tectonic setting over the rifted North American paleocontinental margin that separates Precambrian from Phanerozoic subcontinental lithospheric mantle. Globally, most other significant gold provinces form in volcanic arcs and accreted terranes proximal to convergent margins. In northern Nevada, periodic reactivation of basement faults along this margin focused and amplified subsequent geological events. Early basement faults localized Devonian synsedimentary extension and normal faulting. These controlled the geometry of the Devonian sedimentary basin architecture and focused the discharge of basinal brines that deposited syngenetic gold along the basin margins. Inversion of these basins and faults during subsequent contraction produced the complex elongate structural culminations that characterize the anomalous mineral deposit "trends." Subsequently, these features localized repeated episodes of shallow magmatic and hydrothermal activity that also deposited some gold. During a pulse of Eocene extension, these faults focused advection of Carlin-type fluids, which had the opportunity to leach gold from gold-enriched sequences and deposit it in reactive miogeoclinal host rocks below the hydrologic seal at the Roberts Mountain thrust contact. Hence, the vast endowment of the Carlin province resulted from the conjunction of spatially superposed events localized by long-lived basement structures in a highly anomalous tectonic setting, rather than by the sole operation of special magmatic or fluid-related processes. An important indicator of the longevity of this basement control is the superposition of different gold deposit types (e.g., Sedex, porphyry, Carlin-type, epithermal, and hot spring deposits) that formed repeatedly between the Devonian and Miocene time along the trends. Interestingly, the large Cretaceous Alaska-Yukon intrusion-related gold deposits (e.g., Fort Knox) are associated with the northern extension of the same lithospheric margin in the Selwyn basin, which experienced an analogous series of geologic events. ?? Springer-Verlag 2006.

Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

USGS Publications Warehouse

Johnson, Edward A.; Warwick, Peter D.; Roberts, Stephen B.; Khan, Intizar H.

1999-01-01

The coal-bearing, lower Eocene Ghazij Formation is exposed intermittently over a distance of 750 kilometers along the western margin of the Axial Belt in north-central Pakistan. Underlying the formation are Jurassic to Paleocene carbonates that were deposited on a marine shelf along the pre- and post-rift northern margin of the Indian subcontinent. Overlying the formation are middle Eocene to Miocene marine and nonmarine deposits capped by Pliocene to Pleistocene collision molasse.The lower part of the Ghazij comprises mostly dark gray calcareous mudrock containing foraminifers and rare tabular to lenticular bodies of very fine grained to finegrained calcareous sandstone. We interpret the lower portion of this part of the Ghazij as outer-shelf deposits, and the upper portion as prodelta deposits. The middle part of the formation conformably overlies the lower part. It comprises medium-gray calcareous mudrock containing nonmarine bivalves, fine- to medium-grained calcareous sandstone, and rare intervals of carbonaceous shale and coal. Sandstone bodies in the middle part, in ascending stratigraphic order, are classified as Type I (coarsening-upward grain size, contain the trace fossil Ophiomorpha, and are commonly overlain by carbonaceous shale or coal), Type II (mixed grain size, display wedge-planar cross stratification, and contain fossil oyster shells and Ophiomorpha), and Type III (finingupward grain size, lenticular shape, erosional bases, and display trough cross stratification). These three types of bodies represent shoreface deposits, tidal channels, and fluvial channels, respectively. Mudrock intervals in the lower portion of this part of the formation contain fossil plant debris and represent estuarine deposits, and mudrock intervals in the upper portion contain fossil root traces and represent overbank deposits. We interpret the middle part of the Ghazij as a lower delta plain sequence. Overlying the middle part of the Ghazij, possibly unconformably, is the upper part of the formation, which comprises calcareous, nonfossiliferous, light-gray, brown, and red-banded mudrock, and rare Type III sandstone bodies. Much of the mudrock in this part of the formation represents multiple paleosol horizons. Locally, a limestone-pebble conglomerate is present in the upper part of the formation, either at the base or occupying most of the sequence. We interpret all but the uppermost portion of the upper part of the Ghazij as an upper delta plain deposit.Thin sections of Ghazij sandstones show mostly fragments of limestone, and heavy-liquid separations reveal the presence of chromite. Paleocurrent data and other evidence indicate a northwestern source area.During earliest Eocene time, the outer edge of the marine shelf off the Indian subcontinent collided with a terrestrial fragment positioned adjacent to, but detached from, the Asian mainland. This collision caused distal carbonateplatform deposits to be uplifted, and an intervening intracratonic sea, the Indus Foreland Basin, was created. Thus for the first time, the depositional slope switched from northwest facing to southeast facing, and a northwestern source for detritus was provided. We conclude that the Ghazij was deposited as a prograding clastic wedge along the northwestern shore of this sea, and that the formation contains sedimentologic evidence of a collisional event that predates the main impact between India and Asia.

High genetic diversities between isolates of the fish parasite Cryptocaryon irritans (Ciliophora) suggest multiple cryptic species.

PubMed

Chi, Hongshu; Taik, Patricia; Foley, Emily J; Racicot, Alycia C; Gray, Hilary M; Guzzetta, Katherine E; Lin, Hsin-Yun; Song, Yen-Ling; Tung, Che-Huang; Zenke, Kosuke; Yoshinaga, Tomoyoshi; Cheng, Chao-Yin; Chang, Wei-Jen; Gong, Hui

2017-07-01

The ciliate protozoan Cryptocaryon irritans parasitizes marine fish and causes lethal white spot disease. Sporadic infections as well as large-scale outbreaks have been reported globally and the parasite's broad host range poses particular threat to the aquaculture and ornamental fish markets. In order to better understand C. irritans' population structure, we sequenced and compared mitochondrial cox-1, SSU rRNA, and ITS-1 sequences from 8 new isolates of C. irritans collected in China, Japan, and Taiwan. We detected two SSU rRNA haplotypes, which differ at three positions, separating the isolates into two main groups (I and II). Cox-1 sequences also support the division into two groups, and the cox-1 divergence between these two groups is unexpectedly high (9.28% for 1582 nucleotide positions). The divergence is much greater than that detected in Ichthyophthirius multifiliis, the ciliate protozoan causing freshwater white spot disease in fish, where intraspecies divergence on cox-1 sequence is only 1.95%. ITS-1 sequences derived from these eight isolates and from all other C. irritans isolates (deposited in the GenBank) not only support the two groups, but further suggest the presence of a third group with even greater sequence divergence. Finally, a small Ka/Ks ratio estimated from cox-1 sequences suggests that this gene in C. irritans remains under strong purifying selection. Taken together, the C. irritans species may consists of many subspecies and/or syngens. Further work is needed to determine if there is reproductive isolation between the groups we have defined. Copyright © 2017 Elsevier Inc. All rights reserved.

3D Micro-tomography on Aggregates from the 2014- 2015 Eruption of Hunga Tonga-Hunga Ha'apai Volcano

NASA Astrophysics Data System (ADS)

Colombier, M.; Scheu, B.; Cronin, S. J.; Tost, M.; Dobson, K. J.; Dingwell, D. B.

2016-12-01

In December 2014- January 2015, a surtseyan eruption at Hunga Tonga-Hunga Ha'apai volcano (Tonga) formed a new island. Three main eruptive phases were distinguished by observation and deposits: (i) mound and cone construction, involving collapse of 300-600 m-high wet tephra jets, grain flows, slope-remobilisation and energetic surges, with little or no convective plume (ii) The upper cone-building phase with lower jets (mainly <300 m) but greater ash production (weak, steam-rich plumes to 6 km) and weak surges, and (iii) final phase with weak surge, fall and ballistic deposits with more vesicular pyroclasts producing proximal capping deposits. Most sampled deposits contain ash, lapilli and bombs, and lapilli-sized aggregates are ubiquitous. We used high-resolution 3D X-ray microcomputed tomography (XCT) to quantify the grain size distribution (GSD) and porosity by sampling multiple stratigraphic units within the main eruptive sequences. We visualized and quantified the internal structure of the aggregates to understand the evolution of this surtseyan eruption. We present here an overview of the textural information: porosity, vesicle size distribution and morphology as well as the variability of the aggregation features. Aggregates from the fall deposits of the early wet phase are mostly loosely packed, poorly-structured ash clusters. Aggregates from the early surge sequence and the main cone building phase dominantly exhibit a central particle coated by ash cluster material. Vesicles in the particles from the early fall deposits tend to be smaller and more isolated than in the particles from the surge sequence and the main cone building phase. The GSD of aggregates obtained by XCT is highly valuable to correct the total GSD of volcaniclastic deposits. The strong variations in the aggregation features across the eruption suggest a range of different formation and deposition mechanisms related to varying degrees of magma-water-interaction, which changed the morphology and textural properties of the individual particles.

Comparison of Paleogene paleogeography: Southern Coast Ranges and western Transverse Ranges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schussler, S.A.

1991-02-01

The paleogene stratigraphic sequence exposed in the southwestern San Rafael Mountains at the southern terminus of the Coast Ranges, consists of up to 850 m (2,800 ft) of the marine limestone, sandstone, and mudstone that lies with a unique depositional contact upon Franciscan Complex rocks. Lithofacies identified represent four sedimentary environments: (1) foreslope talus deposits of a neritic algal bank (Sierra Blanca limestone), (2) bathyal basin plain and outer submarine fan deposits (Juncal/Anita Formation and Cozy Dell Shale), (3) suprafan lobe deposits of a bathyal submarine fan (lower Mitilija Sandstone), and (4) sublittoral shelf deposits (upper Matilija Sandstone). Similarities betweenmore » paleogene rocks in the southwest San Rafael mountains and the western Santa Ynez Mountains of the Transverse Ranges, approximately 60 km (40 mi) to the west, suggest deposition in a similar paleogeographic setting. Paleomagnetic data suggests post-Paleogene clockwise rotations of the western Transverse Ranges of 90{degree}+. Counterclockwise rotation of the western Transverse Ranges by this amount aligns the similar depositional sequences of the western Transverse Ranges with the northwest-trending Paleogene forearc basin of the southern Coast Ranges and eliminates the necessity for an east-west-oriented Paleogene basin at the site of the present western Transverse Ranges.« less

Major controls on architecture, sequence stratigraphy and paleosols of middle Pleistocene continental sediments ("Qc Unit"), eastern central Italy

NASA Astrophysics Data System (ADS)

Di Celma, Claudio; Pieruccini, Pierluigi; Farabollini, Piero

2015-05-01

Middle Pleistocene continental sediments in central Italy ("Qc Unit") record the oldest fluvial accumulation along the uplifting margin of the Peri-Adriatic basin. The architecture of the sediment body can be divided into two unconformity-bounded, fining-upward cycles interpreted as genetically related depositional sequences. These sequences highlight the systematic adjustment of the fluvial system to changes in the ratio between accommodation space and sediment supply (A/S ratio) and, from base to top, comprise the following surfaces and stratal components: (i) a regionally correlative sequence boundary resulting from an A/S ratio ≤ 0; (ii) a low-accommodation systems tract characterized by conglomerate-rich, amalgamated channel fills and recording an A/S ratio < 1; (iii) an expansion surface marking the turnaround point from low-accommodation systems tract to high-accommodation systems tract deposits; (iv) a high-accommodation systems tract dominated by floodplain fines encasing lens-like, fluvial channel deposits and denoting an A/S ratio > 1; and (v) a mature red argillic paleosol. To constrain the climatic signal for paleosols formation, the two sequence-capping mature paleosols have been investigated. The results of these studies suggest that they were developed under humid and warm climatic conditions associated with interglacial phases, which have been correlatively attributed to Marine Oxygen Isotope Stages 11 and 9.

Comparing highly ordered monolayers of nanoparticles fabricated using electrophoretic deposition: Cobalt ferrite nanoparticles versus iron oxide nanoparticles

DOE PAGES

Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; ...

2015-08-01

Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

Effect of Sequence Blockiness on the Morphologies of Surface-grafted Elastin-like Polypeptides

NASA Astrophysics Data System (ADS)

Albert, Julie; Sintavanon, Kornkanok; Mays, Robin; MacEwan, Sarah; Chilkoti, Ashutosh; Genzer, Jan

2014-03-01

The inter- and intra- molecular interactions among monomeric units of copolymers and polypeptides depend strongly on monomer sequence distribution and dictate the phase behavior of these species both in solution and on surfaces. To study the relationship between sequence and phase behavior, we have designed a series of elastin-like polypeptides (ELPs) with controlled monomer sequences that mimic copolymers with various co-monomer sequence distributions and attached them covalently to silicon substrates from buffer solutions at temperatures below and above the bulk ELPs' lower critical solution temperatures (LCSTs). The dependence of ELP grafting density on solution temperature was examined by ellipsometry and the resultant surface morphologies were examined in air and under water with atomic force microscopy. Depositions performed above the LCST resulted in higher grafting densities and greater surface roughness of ELPs relative to depositions carried out below the LCST. In addition, we are using gradient substrates to examine the effect of ELP grafting density on temperature responsiveness.

Sequence stratigraphic control on prolific HC reservoir development, Southwest Iran

USGS Publications Warehouse

Lasemi, Y.; Kondroud, K.N.

2008-01-01

An important carbonate formation in the Persian Gulf and the onshore oil fields of Southwest Iran is the Lowermost Cretaceous Fahliyan formation. The formation in Darkhowain field consists of unconformity-bounded depositional sequences containing prolific hydrocarbon reservoirs of contrasting origin. Located in the high stand systems tract (HST) of the lower sequence encompassing over 200m of oil column are the most prolific reservoir. Another reservoir is over 80m thick consisting of shallowing-upward cycles that are best developed within the transgressive systems tract of the upper sequence. Vertical facies distribution and their paleobathymetry and geophysical log signatures of the Fahliyan formation in the Darkhowain platform reveal the presence of two unconformity-bounded depositional sequences in Vail et al., Van Wagoner et al., and Sarg. The Fahliyan formation mainly consists of platform carbonates composed of restricted bioclastic lime mudstone to packstone of the platform interior, Lithocodium boundstone or ooid-intraclast-bioclast grainstone of the high energy platform margin and the bioclast packstone to lime mudstone related to the off-platform setting.

Lithofacies and sequence stratigraphic description of the upper part of the Avon Park Formation and the Arcadia Formation in U.S. Geological Survey G–2984 test corehole, Broward County, Florida

USGS Publications Warehouse

Cunningham, Kevin J.; Robinson, Edward

2017-07-18

Rock core and sediment from U.S. Geological Survey test corehole G–2984 completed in 2011 in Broward County, Florida, provide an opportunity to improve the understanding of the lithostratigraphic, sequence stratigraphic, and hydrogeologic framework of the intermediate confining unit and Floridan aquifer system in southeastern Florida. A multidisciplinary approach including characterization of sequence stratigraphy, lithofacies, ichnology, foraminiferal paleontology, depositional environments, porosity, and permeability was used to describe the geologic samples from this test corehole. This information has produced a detailed characterization of the lithofacies and sequence stratigraphy of the upper part of the middle Eocene Avon Park Formation and Oligocene to middle Miocene Arcadia Formation. This enhancement of the knowledge of the sequence stratigraphic framework is especially important, because subaerial karst unconformities at the upper boundary of depositional cycles at various hierarchical scales are commonly associated with secondary porosity and enhanced permeability in the Floridan aquifer system.

Evaluation of the authenticity of a highly novel environmental sequence from boreal forest soil using ribosomal RNA secondary structure modeling

Treesearch

D.J. Glass; N. Takebayashi; L. Olson; D.L. Taylor

2013-01-01

The number of sequences from both formally described taxa and uncultured environmental DNA deposited in the International Nucleotide Sequence Databases has increased substantially over the last two decades. Although the majority of these sequences represent authentic gene copies, there is evidence of DNA artifacts in these databases as well. These include lab artifacts...

Draft Genome Sequence of Ideonella sp. Strain A 288, Isolated from an Iron-Precipitating Biofilm

PubMed Central

Künzel, Sven; Szewzyk, Ulrich

2017-01-01

ABSTRACT Here, we report the draft genome sequence of the betaproteobacterium Ideonella sp. strain A_228. This isolate, obtained from a bog iron ore-containing floodplain area in Germany, provides valuable information about the genetic diversity of neutrophilic iron-depositing bacteria. The Illumina NextSeq technique was used to sequence the draft genome sequence of the strain. PMID:28818902

Constraints on the depositional age and tectonometamorphic evolution of marbles from the Biharia Nappe System (Apuseni Mountains, Romania)

NASA Astrophysics Data System (ADS)

Reiser, Martin Kaspar; Schuster, Ralf; Tropper, Peter; Fügenschuh, Bernhard

2017-04-01

Basement rocks from the Biharia Nappe System in the Apuseni Mountains comprise several dolomite and calcite marble sequences or lenses which experienced deformation and metamorphic overprint during the Alpine orogeny. New Sr, O and C-isotope data in combination with considerations from the lithological sequences indicate Middle to Late Triassic deposition of calcite marbles from the Vulturese-Belioara Series (Biharia Nappe s.str.). Ductile deformation and large-scale folding of the siliciclastic and carbonatic lithologies is attributed to NW-directed nappe stacking during late Early Cretaceous times (D2). The studied marble sequences experienced a metamorphic overprint under lower greenschist- facies conditions (316-370 °C based on calcite - dolomite geothermometry) during this tectonic event. Other marble sequences from the Biharia Nappe System (i.e. Vidolm and Baia de Arieș nappes) show similarities in the stratigraphic sequence and their isotope signature, together with a comparable structural position close to nappe contact. However, the dataset is not concise enough to allow for a definitive attribution of a Mesozoic origin to other marble sequences than the Vulturese-Belioara Series.

NGS Catalog: A Database of Next Generation Sequencing Studies in Humans

PubMed Central

Xia, Junfeng; Wang, Qingguo; Jia, Peilin; Wang, Bing; Pao, William; Zhao, Zhongming

2015-01-01

Next generation sequencing (NGS) technologies have been rapidly applied in biomedical and biological research since its advent only a few years ago, and they are expected to advance at an unprecedented pace in the following years. To provide the research community with a comprehensive NGS resource, we have developed the database Next Generation Sequencing Catalog (NGS Catalog, http://bioinfo.mc.vanderbilt.edu/NGS/index.html), a continually updated database that collects, curates and manages available human NGS data obtained from published literature. NGS Catalog deposits publication information of NGS studies and their mutation characteristics (SNVs, small insertions/deletions, copy number variations, and structural variants), as well as mutated genes and gene fusions detected by NGS. Other functions include user data upload, NGS general analysis pipelines, and NGS software. NGS Catalog is particularly useful for investigators who are new to NGS but would like to take advantage of these powerful technologies for their own research. Finally, based on the data deposited in NGS Catalog, we summarized features and findings from whole exome sequencing, whole genome sequencing, and transcriptome sequencing studies for human diseases or traits. PMID:22517761

Factors controlling mud accumulation in the Heuksan mud belt off southwestern Korea

NASA Astrophysics Data System (ADS)

Chang, Tae Soo; Ha, Hun Jun; Chun, Seung Soo

2015-12-01

The Heuksan mud belt (hereafter HMB) is 20~50 km wide, ~200 km long, and ~50 m thick, having accumulated in the course of the Holocene transgression on the tide-dominated epicontinental shelf southwest of Korea. The internal architecture of the HMB is characterized by offshore prograding clinoforms. Of particular interest are the depositional processes responsible for this anomalously thick mud accumulation within a relatively short period of time. Tidal currents are important in the dispersal of mud in the HMB, although these alone cannot explain such an enormous mud deposit. In order to understand the formative processes of the HMB, a detailed sedimentary facies analysis, including high-resolution grain-size measurements, has been conducted on more than 30 short cores and three long drill cores recovered from the mud belt. Five major mud facies were identified. Of these, mud sequences showing a thickening-thinning trend of alternating silt and clay laminae suggestive of a tidal origin occur dominantly at inner to mid shelf locations. By contrast, internally structureless muds with sharp bases and no bioturbation, which are interpreted of representing fluid-mud deposits, are widespread at mid to outer shelf locations. Wave-generated mud ripples and storm beds on the inner shelf suggest that storm waves in winter resuspend previously deposited mud to form near-bed fluid-mud suspensions with resulting gravity-driven mud transport across the low-gradient outer shelf. This previously not recognized process is probably a major factor controlling depositional processes on the giant mud belt, enabling rapid accumulation and offshore progradation even during transgression, i.e., at times of sea-level rise.

Magnetic signature of the 22 June 1932 tsunami deposits (Jalisco, Mexican Pacific coast)

NASA Astrophysics Data System (ADS)

Bógalo, M. F.; Ramírez-Herrera, M.-T.; Goguitchaichvili, A.; Rey, D.; Mohamed, K. J.; Calvo-Rathert, M.; Corona, N.

2017-06-01

Recent studies have demonstrated that rock-magnetic analysis may provide additional information to distinguish and characterize extreme marine inundation events such as tsunamis. Rock-magnetic proxies reinforce and improve the environmental evidences supplied by other methods, adding some decisive clues for the interpretation of the origin and genesis of the sedimentary deposits. Here we report rock-magnetic, XRD, and SEM microscopy results obtained in the Palo Verde estuary (Colima Pacific coast, Mexico) in order to enhance the tools for identification and reconstruction of two tsunami-induced deposits. The sedimentary sequence includes two sand units, a tsunami deposit (PV1) associated with the 22 June 1932 tsunami and a deeper sandy layer (PV2) related to a possible paleotsunami that occurred around 1300 C.E. Both sandy units are topped by finer grained units. Magnetic properties exhibit a significant correlation with the stratigraphy. High susceptibility (χ) and high saturation isothermal remanence (SIRM) values typical of high concentrations of (titano)magnetite are a distinctive feature of the most recent sandy tsunamigenic unit PV1 and the overlaying soil. The lower sandy tsunamigenic unit PV2 shows significantly lower χ and SIRM values, indicating lower concentration of (titano)magnetite in this unit and the overlaying clayey-silt unit. The latter also shows a higher coercivity component associated with (titano)hematite. Magnetic grain-size differences are also observed between PV1 and PV2 suggesting differences in hydraulic conditions at the time of deposition. The bulk mineralogical composition and sediment texture of these units also support the hypothesis of different provenances for each tsunamigenic unit as inferred from magnetic properties.

Geochemistry of Precambrian carbonates. IV - Early Paleoproterozoic (2.25 +/- 0.25 Ga) seawater

NASA Technical Reports Server (NTRS)

Veizer, Jan; Clayton, R. N.; Hinton, R. W.

1992-01-01

The mineralogy, chemistry, and isotopic composition of the Malmani Dolomite, Duck Creek Dolomite, and Bruce 'Limestone' Member of the Espanola Formation are studied in an effort to restrict the first- and second-order variations in isotopic composition of Early Paleoproterozoic seawater. The diagenetic rank is found to increase in the order Duck Creek less than Bruce less than Malmani. The interpolation of alteration trends to 'best' value yields an estimate of 0.70550 for Sr-87/Sr-86. For delta C-13, the measured range of 0 +/- 1.5 percent PDB is similar to that observed for Phanerozoic marine carbonates, while the 'best' delta O-18 value for dolostones is -5 percent PDB, depleted in O-18 relative to Phanerozoic counterparts but comparable to estimates obtained for Archean facies. The isotope geochemistry and mineralogy of Bruce 'Limestone' Member is consistent with the proposition that the sequence was deposited in a lacustrine environment.

Constraining controls on carbonate sequences with high-resolution chronostratigraphy: Upper Miocene, Cabo de Gata region, SE Spain

USGS Publications Warehouse

Montgomery, P.; Farr, M.R.; Franseen, E.K.; Goldstein, R.H.

2001-01-01

A high-resolution chronostratigraphy has been developed for Miocene shallow-water carbonate strata in the Cabo de Gata region of SE Spain for evaluation of local, regional and global factors that controlled platform architecture prior to and during the Messinian salinity crisis. Paleomagnetic data were collected from strata at three localities. Mean natural remanent magnetization (NRM) ranges between 1.53 ?? 10-8 and 5.2 ?? 10-3 Am2/kg. Incremental thermal and alternating field demagnetization isolated the characteristic remanent magnetization (ChRM). Rock magnetic studies show that the dominant magnetic mineral is magnetite, but mixtures of magnetite and hematite occur. A composite chronostratigraphy was derived from five stratigraphic sections. Regional stratigraphic data, biostratigraphic data, and an 40Ar/39Ar date of 8.5 ?? 0.1 Ma, for an interbedded volcanic flow, place the strata in geomagnetic polarity Chrons C4r to C3r. Sequence-stratigraphic and diagenetic evidence indicate a major unconformity at the base of depositional sequence (DS)3 that contains a prograding reef complex, suggesting that approximately 250 000 yr of record (Subchrons C3Br.2r to 3Br.1r) are missing near the Messinian-Tortonian boundary. Correlation to the GPTS shows that the studied strata represent five third- to fourth-order DSs. Basal units are temperate to subtropical ramps (DS1A, DS1B, DS2); these are overlain by subtropical to tropical reefal platforms (DS3), which are capped by subtropical to tropical cyclic carbonates (Terminal Carbonate Complex, TCC). Correlation of the Cabo de Gata record to the Melilla area of Morocco, and the Sorbas basin of Spain indicate that early - Late Tortonian ramp strata from these areas are partially time-equivalent. Similar strata are extensively developed in the Western Mediterranean and likely were influenced by a cool climate or influx of nutrients during an overall rise in global sea-level. After ramp deposition, a sequence boundary (SB3) in Cabo de Gata correlates with a sequence boundary in Morocco and a published third-order eustatic fall suggesting at least a partial eustatic control for the sequence boundary. Coral reefs began to develop earlier in Cabo de Gata than at Melilla or Sorbas, arguing for local factors affecting this major environmental transition. Later Messinian reefs (DS3) from all areas are time-equivalent, suggesting a regional or global control on their formation. Some Halimeda-rich horizons in the Western Mediterranean are not time-equivalent event strata as hypothesized by others. Correlation of the relative sea-level curve for the fringing reef complex (DS3) with a published eustatic curve suggests at least a partial third-order global eustatic control for the highstand part of the sequence. Downstepping DS3 reefs and initial subaerial exposure of earlier DS3 reef strata approximately correlate with initiation of a series of subaerial unconformities in the South Pacific. The longer-term relative fall in sea-level during DS3 downstepping reef progradation does not correlate with a published third-order eustatic fall. Eustatic sea-level fluctuations may have been associated with initiation of the Mediterranean Messinian salinity crisis, but the longer-term fall may have been linked to tectonic uplift in the Mediterranean region. Widespread distribution of 'TCC-style' cycles of approximately the same age suggests a regional (Western Mediterranean) or global control on sea-level change responsible for TCC cycles. In addition, four subaerial exposure-capped TCC cycles may correlate with similar subaerial unconformities in the South Pacific, suggesting at least a partial eustatic control on TCC cyclicity. The high rates of relative sea-level change needed to generate a minimum of 25-30 m sea-level changes associated with each cycle are consistent with glacio-eustacy along with rapid evaporitic drawdown in the Mediterranean. ?? 2001 Elsevier Science B.V. All rights reserved.

Dichotomy Boundary at Aeolis Mensae, Mars: Fretted Terrain Developed in a Sedimentary Deposit

NASA Astrophysics Data System (ADS)

Irwin, R. P., III; Watters, T. R.; Howard, A. D.; Maxwell, T. A.; Craddock, R. A.

2003-03-01

Fretted terrain in Aeolis Mensae, Mars, developed in a sedimentary deposit. A thick, massive unit with a capping layer or duricrust overlies a more durable layered sequence. Wind, collapse, and minor fluvial activity contributed to degradation.

Site formation processes at Pinnacle Point Cave 13B (Mossel Bay, Western Cape Province, South Africa): resolving stratigraphic and depositional complexities with micromorphology.

PubMed

Karkanas, Panagiotis; Goldberg, Paul

2010-01-01

Site PP13B is a cave located on the steep cliffs of Pinnacle Point near Mossel Bay in Western Cape Province, South Africa. The depositional sequence of the cave, predating Marine Isotopic Stage 11 (MIS 11) and continuing to present, is in the form of isolated sediment exposures with different depositional facies and vertical and lateral variations. Micromorphological analysis demonstrated that a suite of natural sedimentation processes operated during the development of the sequence ranging from water action to aeolian activity, and from speleothem formations to plant colonization and root encrustation. At the same time, anthropogenic sediments that are mainly in the form of burnt remains from combustion features (e.g., wood ash, charcoal, and burnt bone) were accumulating. Several erosional episodes have resulted in a complicated stratigraphy, as discerned from different depositional and post-depositional features. The cave is associated with a fluctuating coastal environment, frequent changes in sea level and climate controlled patterns of sedimentation, and the presence or absence of humans. Copyright © 2010 Elsevier Ltd. All rights reserved.

Serial PIB and MRI in normal, mild cognitive impairment and Alzheimer's disease: implications for sequence of pathological events in Alzheimer's disease.

PubMed

Jack, Clifford R; Lowe, Val J; Weigand, Stephen D; Wiste, Heather J; Senjem, Matthew L; Knopman, David S; Shiung, Maria M; Gunter, Jeffrey L; Boeve, Bradley F; Kemp, Bradley J; Weiner, Michael; Petersen, Ronald C

2009-05-01

The purpose of this study was to use serial imaging to gain insight into the sequence of pathologic events in Alzheimer's disease, and the clinical features associated with this sequence. We measured change in amyloid deposition over time using serial (11)C Pittsburgh compound B (PIB) positron emission tomography and progression of neurodegeneration using serial structural magnetic resonance imaging. We studied 21 healthy cognitively normal subjects, 32 with amnestic mild cognitive impairment and 8 with Alzheimer's disease. Subjects were drawn from two sources--ongoing longitudinal registries at Mayo Clinic, and the Alzheimer's disease Neuroimaging Initiative (ADNI). All subjects underwent clinical assessments, MRI and PIB studies at two time points, approximately one year apart. PIB retention was quantified in global cortical to cerebellar ratio units and brain atrophy in units of cm(3) by measuring ventricular expansion. The annual change in global PIB retention did not differ by clinical group (P = 0.90), and although small (median 0.042 ratio units/year overall) was greater than zero among all subjects (P < 0.001). Ventricular expansion rates differed by clinical group (P < 0.001) and increased in the following order: cognitively normal (1.3 cm(3)/year) < amnestic mild cognitive impairment (2.5 cm(3)/year) < Alzheimer's disease (7.7 cm(3)/year). Among all subjects there was no correlation between PIB change and concurrent change on CDR-SB (r = -0.01, P = 0.97) but some evidence of a weak correlation with MMSE (r =-0.22, P = 0.09). In contrast, greater rates of ventricular expansion were clearly correlated with worsening concurrent change on CDR-SB (r = 0.42, P < 0.01) and MMSE (r =-0.52, P < 0.01). Our data are consistent with a model of typical late onset Alzheimer's disease that has two main features: (i) dissociation between the rate of amyloid deposition and the rate of neurodegeneration late in life, with amyloid deposition proceeding at a constant slow rate while neurodegeneration accelerates and (ii) clinical symptoms are coupled to neurodegeneration not amyloid deposition. Significant plaque deposition occurs prior to clinical decline. The presence of brain amyloidosis alone is not sufficient to produce cognitive decline, rather, the neurodegenerative component of Alzheimer's disease pathology is the direct substrate of cognitive impairment and the rate of cognitive decline is driven by the rate of neurodegeneration. Neurodegeneration (atrophy on MRI) both precedes and parallels cognitive decline. This model implies a complimentary role for MRI and PIB imaging in Alzheimer's disease, with each reflecting one of the major pathologies, amyloid dysmetabolism and neurodegeneration.

The morphology, processes, and evolution of Monterey Fan: a revisit

USGS Publications Warehouse

Gardner, James V.; Bohannon, Robert G.; Field, Michael E.; Masson, Douglas G.

2010-01-01

Long-range (GLORIA) and mid-range (TOBI) sidescan imagery and seismic-reflection profiles have revealed the surface morphology and architecture of the complete Monterey Fan. The fan has not developed a classic wedge shape because it has been blocked for much of its history by Morro Fracture Zone. The barrier has caused the fan to develop an upper-fan and lower-fan sequence that are distinctly different from one another. The upper-fan sequence is characterized by Monterey and Ascension Channels and associated Monterey Channel-levee system. The lower-fan sequence is characterized by depositional lobes of the Ascension, Monterey, and Sur-Parkington-Lucia systems, with the Monterey depositional lobe being the youngest. Presently, the Monterey depositional lobe is being downcut because the system has reached a new, lower base level in the Murray Fracture Zone. A five-step evolution of Monterey Fan is presented, starting with initial fan deposition in the Late Miocene, about 5.5 Ma. This first stage was one of filling bathymetric lows in the oceanic basement in what was to become the upper-fan segment. The second stage involved filling the bathymetric low on the north side of Morro Fracture Zone, and probably not much sediment was transported beyond the fracture zone. The third stage witnessed sediment being transported around both ends of Morro Fracture Zone and initial sedimentation on the lower-fan segment. During the fourth stage Ascension Channel was diverted into Monterey Channel, thereby cutting off sedimentation to the Ascension depositional lobe.

[Analysis of FABP4 expression pattern in rump fat deposition and metabolism of Altay sheep].

PubMed

Ruixia, Xu; Lei, Gao; Weili, Zhao; Wei, Zhang; Guangchao, Song; Shangquan, Gan; Guoqing, Shi

2015-02-01

FABP4 (Fatty acid binding protein 4) is a hot candidate gene in fat deposition and lipid metabolism and participates in the transport and metabolism of intracellular free fatty acids. We aim to study the role of FABP4 in fat deposition and metabolism of the rump fat in Altay sheep. In this study, bioinformatics method was used to analyze the protein sequence homology among 10 species, and RT-PCR was employed to detect FABP4 tissue profiling of Altay sheep. An animal model simulating the rump fat deposition and metabolism of Altay sheep was established by continuous starvation, and qPCR and iTRAQ (isobaric tags for relative and absolute quantitation) were used to detecte FABP4 mRNA and protein expression changes in the control and continuous starvation groups, respectively. Sequence analysis showed that FABP4 protein sequence is highly conserved among species, suggesting an important biological function during evolution for FABP4. The RT-PCR result confirmed that FABP4 mRNA was highly expressed in intestinal and rump fat, suggesting that FABP4 plays an important physiological role in fat tissues. We did not find significant differences in FABP4 mRNA and protein between control and continuous starvation groups (P>0.05), which indicates that FABP4 may not be the key gene in fat deposition and metabolism in Altay sheep.The results above lay a foundation for further studies of FABP4 in rump or tail fat.

The complete mitochondrial genome of lesser long-tailed Hamster Cricetulus longicaudatus (Milne-Edwards, 1867) and phylogenetic implications.

PubMed

Zhang, Ziqi; Sun, Tong; Kang, Chunlan; Liu, Yang; Liu, Shaoying; Yue, Bisong; Zeng, Tao

2016-01-01

The complete mitochondrial genome sequence of Cricetulus longicaudatus (Rodentia Cricetidae: Cricetinae) was determined and was deposited in GenBank (GenBank accession no. KM067270). The mitochondrial genome of C. longicaudatus was 16,302 bp in length and contained 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and one control region, with an identical order to that of other rodents' mitochondrial genomes. The phylogenetic analysis was performed with Bayesian inference based on the concatenated nucleotide sequence of 12 protein-coding genes on the heavy strand. The result showed that these species from Cricetidae and its two subfamilies (Cricetinae and Arvicolines) formed solid monophyletic group, respectively. The Cricetulus had close phylogenetic relationship with Tscherskia among three genera (Cricetulus, Cricetulus and Mesocricetus). Neodon irene and Myodes regulus were embedded in Microtus and Eothenomys, respectively. The unusual phylogenetic positions of Neodon irene and Myodes regulus remain further study in the future.

Tidal-bundle sequences in the Jordan Sandstone (Upper Cambrian), southeastern Minnesota, U.S.A.: Evidence for tides along inboard shorelines of the Sauk Epicontinental Sea

USGS Publications Warehouse

Tape, C.H.; Cowan, Clinton A.; Runkel, Anthony C.

2003-01-01

This study documents for the first time tidal bundling in a lower Paleozoic sheet sandstone from the cratonic interior of North America, providing insights into the hydrodynamics of ancient epicontinental seas. The Jordan Sandstone (Upper Cambrian) in the Upper Mississippi Valley contains large-scale planar tabular cross-sets with tidal-bundle sequences, which were analyzed in detail at an exceptional exposure. Tidal-bundle sequences (neap-spring-neap cycles) were delineated by foreset thickening-thinning patterns and composite shale drapes, the latter of which represent accumulations of mud during the neap tides of neap-spring-neap tidal cycles. Fourier analysis of the bundle thickness data from the 26 measurable bundle sequences revealed cycles ranging from 15 to 34 bundles per sequence, which suggests a semidiurnal or mixed tidal system along this part of the Late Cambrian shoreline. We extend the tidal interpretation to widespread occurrences of the same facies in outcrops of lesser quality, where the facies is recognizable but too few bundles are exposed for tidal cycles to be measured. By doing so, this study shows that tidally generated deposits have a significant geographic and temporal extent in Upper Cambrian strata of central mid-continent North America. The deposition and preservation of tidal facies was related to the intermittent development of shoreline embayments during transgressions. The tidally dominated deposits filled ravined topographies that were repeatedly developed on the updip parts of the shoreface. Resulting coastal geomorphologies, accompanied perhaps by larger-scale changes in basinal conditions and/or configuration, led to changes in depositional conditions from wave-dominated to tide-dominated. Outcrops of the Jordan Sandstone tidal facies in the Upper Mississippi Valley represent the farthest inboard recorded transmission of ocean-generated tides in the Laurentian epicontinental seas, demonstrating that tidal currents were significant agents in the transport of sand along the far cratonic interior shorelines of Cambrian North America. The results of this study improve the facies-level understanding of the genesis of sheet sandstones. Furthermore, tidalites documented here occur in a specific position within a sequence stratigraphic architecture for the Jordan Sandstone. This provides a framework to compare these ancient deposits and processes to younger (e.g., Carboniferous) epicontinental systems where stratal and sediment dynamics are better documented. ?? 2003, SEPM (Society for Sedimentary Geology).

11 CFR 111.12 - Subpoenas and subpoenas duces tecum; depositions (2 U.S.C. 437d(a) (3), (4)).

Code of Federal Regulations, 2010 CFR

2010-01-01

... subpoenas duces tecum for the production of documentary or other tangible evidence in connection with a deposition or otherwise. (b) If oral testimony is ordered to be taken by deposition or documents are ordered...

Identification of putative candidate genes involved in cuticle formation in Prunus avium (sweet cherry) fruit

PubMed Central

Alkio, Merianne; Jonas, Uwe; Sprink, Thorben; van Nocker, Steven; Knoche, Moritz

2012-01-01

Background and Aims The cuticular membrane (CM) of Prunus avium (sweet cherry) and other fleshy fruit is under stress. Previous research indicates that the resultant strain promotes microscopic cuticular cracking. Microcracks impair the function of the CM as a barrier against pathogens and uncontrolled water loss/uptake. Stress and strain result from a cessation of CM deposition during early development, while the fruit surface continues to expand. The cessation of CM deposition, in turn, may be related to an early downregulation of CM-related genes. The aims of this study were to identify genes potentially involved in CM formation in sweet cherry fruit and to quantify their expression levels. Methods Fruit growth and CM deposition were quantified weekly from anthesis to maturity and rates of CM deposition were calculated. Sequences of genes expressed in the sweet cherry fruit skin (exocarp) were generated using high-throughput sequencing of cDNA and de novo assembly and analysed using bioinformatics tools. Relative mRNA levels of selected genes were quantified in the exocarp and fruit flesh (mesocarp) weekly using reverse transcriptase-quantitative real-time PCR and compared with the calculated CM deposition rate over time. Key Results The rate of CM deposition peaked at 93 (±5) μg per fruit d−1 about 19 d after anthesis. Based on sequence analyses, 18 genes were selected as potentially involved in CM formation. Selected sweet cherry genes shared up to 100 and 98 % similarity with the respective Prunus persica (peach) and Arabidopsis thaliana genes. Expression of 13 putative CM-related genes was restricted to the exocarp and correlated positively with the CM deposition rate. Conclusions The results support the view that the cessation of CM deposition during early sweet cherry fruit development is accounted for by a downregulation of genes involved in CM deposition. Genes that merit further investigation include PaWINA, PaWINB, PaLipase, PaLTPG1, PaATT1, PaLCR, PaGPAT4/8, PaLACS2, PaLACS1 and PaCER1. PMID:22610921

Graben calderas of the Sierra Madre Occidental: The case of Guanajuato, central Mexico

NASA Astrophysics Data System (ADS)

Aguirre-Diaz, G. J.; Tristán-González, M.; Labarthe-Hernández, G.; Marti, J.

2013-12-01

The Sierra Madre Occidental (SMO) volcanic province is characterized by voluminous silicic ignimbrites that reach an accumulated thickness of 500 to 1500 m. A single ignimbrite can reach up to 350 m thick in its outflow facies. This ignimbrite sequence formed mostly within 38-23 Ma, building up a total estimated volume of ca. 580,000 km3 making the SMO the largest ignimbrite province of the world. We have showed that several and probably most of the SMO ignimbrites were erupted from fissures associated to Basin and Range fault systems or grabens (Geology, 2003), thus naming these volcano-tectonic structures as graben calderas (Caldera Volcanism book, Elsevier, 2008). Generally, the sequence observed in graben calderas include, from oldest to youngest, alluvial fan deposits combined with lacustrine deposits, pyroclastic surge deposits and minor volume ignimbrites, a large-volume ignimbrite that could be massive or made of successive layers, and sometimes silicic lava domes and/or mafic fissural lavas both with vents aligned with the graben trend. Fallout deposits, plinian or non-plinian, are not observed in the sequence. Thus, onset of caldera collapse represented by the major ignimbrite must occur just after deposition of continental sediments within the graben domain. A similar volcano-tectonic development is observed in pull-apart grabens. Therefore, extensional or transtensional tectonics, before and during caldera collapse, and the emplacement of a subgraben shallow silicic magma chamber are the necessary conditions for the development of graben calderas. We describe here the case of the Guanajuato graben caldera, located in the central part of Mexico and in the southeastern portion of the SMO volcanic province. The caldera is part of the economically important mining district of Guanajuato, with 28 silver mines, some active since the 16th century. The caldera structure, a rectangle of 10 x 16 km, was controlled by NW and NE regional fault systems. Most ore deposits occur along this orthogonal faulting network, but mainly along the NW fault of Veta Madre that crosses through the center of the caldera. The mid-Tertiary stratigraphy in Guanajuato follows the general sequence observed in graben calderas; i.e., from oldest to youngest includes 1) at least 1,500 m of alluvial fan deposits within a tectonic basin (Guanajuato Red Conglomerate), 2) pyroclastic flow deposits, consisting of surge deposits (Loseros Formation) that are concordant with a massive, large volume, rhyolitic ignimbrite (Bufa Rhyolite), which is covered by a layered series of pyroclastic flow deposits (Calderones Formation), and 3) effusive volcanism in the form of rhyolitic lava domes (Chichíndaro Rhyolite) and basaltic-andesite dikes and lavas (Cedros Andesite). The Guanajuato graben caldera formed at about 33 Ma, based on our new U-Pb zr age of the main ignimbrite, Bufa Rhyolite.

Lagoonal deposits in the Upper Cretaceous Rock Springs Formation (Mesaverde Group), southwest Wyoming

USGS Publications Warehouse

Kirschbaum, M.A.

1989-01-01

Most paleogeographic reconstructions of the Rock Springs Formation show shorelines having lobate to arcuate deltas. These shorelines are oriented NE-SW, with the sea to the southeast. Brackish-water bodies are usually shown in interdistributary areas or associated with abandoned delta lobes, and are open to the sea. In this study, a sedimentary sequence 30-50 m thick is interpreted as interdeltaic deposits. Brackish-water deposits within the sequence are interpreted as interdeltaic lagoons rather than interdistributary bays. Three facies associations (units) are recognized in nine measured sections of the study interval. Unit A consists of interbedded sandstone, mudrock and coal which occur in both fining- and coarsening-upward sequences less than 10 m thick. Fining-upward sequences decrease in thickness and frequency upwards in unit A and are interpreted as distributary channels. Coarsening-upward sequences associated with the channels are interpreted as crevasse splays that filled lakes or interdistributary bays. In the upper part of the unit where only minor channels are present, the coarsening-upward sequences are interpreted as bay deltas. Unit B consists of fossiliferous silty shale and bioturbated sandy siltstone. A low-diversity fauna of bivalves, gastropods, ostracods and foraminifers indicates that brackish-water conditions existed. Unit B intertongues with unit A to the northwest and with unit C to the southeast, and is interpreted as lagoonal deposits. Unit C consists of crossbedded and burrowed sandstone in beds 0.5-9 m thick. Sandstones are laterally continuous in the southeast but become tabular bodies enclosed within unit B to the northwest. Laterally continuous sandstones are interpreted as shoreface deposits on the basis of multidirectional crossbeds, marine trace fossils and continuity. Tabular sandstones are interpreted as flood-tidal deltas on the basis of NW-oriented crossbeds, pinchouts to the northwest and enclosure within unit B. Scoured surfaces and rip-up clasts within unit C indicate the presence of tidal channels or inlets. Interpreting unit B as an interdeltaic lagoon rather than an interdistributary bay is dependent on understanding its enclosing strata. The distributary channels of unit A supplied the majority of the sediment in the lower part of the sequence. However, after the lagoon formed, tidal channels and inlets of unit C supplied more sediment to the area than channels of unit A. The shift in sedimentation from a landward to a seaward source reflects the change from a delta plain to an interdeltaic lagoon following abandonment of distributary channels. ?? 1989.

Sequence stratigraphy of an Oligocene carbonate shelf, Central Kalimantan, Indonesia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saller, A.; Armin, R.; Ichram, L.O.

1991-03-01

Interpretations of Oligocene shelfal limestones from Central Kalimantan, Indonesia, suggest caution in predicting sea-level lowstands from seismic reflector patterns or published sea-level curves. Three major depositional sequences, each 200-400 m thick, were delineated in outcrops and seismic lines: late Eocene to early Oligocene (34-38 Ma), middle Oligocene (29.7-32 Ma), and early late Oligocene (28-29.7 Ma). The lowest sequence is mainly shale with tin sandstones and limestones (large-foram wackestone). The middle and upper sequences are carbonate with transgressive systems tracts (TSTs) overlain by highstand systems tracts (HSTs). TSTs contain large-foram wackestone-packstones and coral wackestone-packstones. HSTs are characterized by (1) shale andmore » carbonate debris flows deposited on the lower slope, (2) argillaceous large-foram wackestones on the upper slope, (3) discontinuous coral wackestones and boundstones on the shelf margin, (4) bioclastic packstones and grainstones on backreef flats and shelf-margin shoals, and (5) branching-coral and foraminiferal wackestones in the lagoon. Bases of sequences are characterized by transgression and onlap. Deepending and/or drowning of the carbonate shelf occurred at the top of the middle and upper sequences. Basinal strata that apparently onlap the middle and upper carbonate shelf margins might be misinterpreted as lowstand deposits, although regional studies indicate they are prodelta sediments baselapping against the shelf. Shallowing the subaerial exposure of the carbonates might be expected during the large mid-Oligocene (29.5-30 Ma) sea-level drop of Haq et al. (1987), instead of the observed deepening and local drowning.« less

Optimal likelihood-based matching of volcanic sources and deposits in the Auckland Volcanic Field

NASA Astrophysics Data System (ADS)

Kawabata, Emily; Bebbington, Mark S.; Cronin, Shane J.; Wang, Ting

2016-09-01

In monogenetic volcanic fields, where each eruption forms a new volcano, focusing and migration of activity over time is a very real possibility. In order for hazard estimates to reflect future, rather than past, behavior, it is vital to assemble as much reliable age data as possible on past eruptions. Multiple swamp/lake records have been extracted from the Auckland Volcanic Field, underlying the 1.4 million-population city of Auckland. We examine here the problem of matching these dated deposits to the volcanoes that produced them. The simplest issue is separation in time, which is handled by simulating prior volcano age sequences from direct dates where known, thinned via ordering constraints between the volcanoes. The subproblem of varying deposition thicknesses (which may be zero) at five locations of known distance and azimuth is quantified using a statistical attenuation model for the volcanic ash thickness. These elements are combined with other constraints, from widespread fingerprinted ash layers that separate eruptions and time-censoring of the records, into a likelihood that was optimized via linear programming. A second linear program was used to optimize over the Monte-Carlo simulated set of prior age profiles to determine the best overall match and consequent volcano age assignments. Considering all 20 matches, and the multiple factors of age, direction, and size/distance simultaneously, results in some non-intuitive assignments which would not be produced by single factor analyses. Compared with earlier work, the results provide better age control on a number of smaller centers such as Little Rangitoto, Otuataua, Taylors Hill, Wiri Mountain, Green Hill, Otara Hill, Hampton Park and Mt Cambria. Spatio-temporal hazard estimates are updated on the basis of the new ordering, which suggest that the scale of the 'flare-up' around 30 ka, while still highly significant, was less than previously thought.

Eustatic control on epicontinental basins: The example of the Stuttgart Formation in the Central European Basin (Middle Keuper, Late Triassic)

NASA Astrophysics Data System (ADS)

Franz, M.; Nowak, K.; Berner, U.; Heunisch, C.; Bandel, K.; Röhling, H.-G.; Wolfgramm, M.

2014-11-01

The deposition of the Stuttgart Formation ('Schilfsandstein'), commonly considered as a type-example of the Carnian Pluvial Event, was controlled by high frequent 4th order sequences that resulted in pre-, intra- and post-Schilfsandstein transgressions from Tethyan waters into the epicontinental Central European Basin (CEB). The pre-Schilfsandstein transgression flooded the CEB trough gates to the Southeast and resulted in a wide-spread inland sea that was characterised by increased biological productivity, predominantly oxic conditions and enabled the immigration of euryhaline marine fauna with plankton, ostracodes, fishes, bivalves and the gastropods Omphaloptychia suebica n. sp. and Settsassia stuttgartica n. sp. The rather short-term intra- and post-Schilfsandstein transgressions flooded the CEB from the Southwest and Southeast and established a shallow brackish inland sea that stretched up to North Germany. Both, the 4th and 3rd order sequences derived from the succession in the CEB correlate well with those derived from successions of Tethyan shelfs. Therefore pronounced circum-Tethyan eustatic cycles are evidenced and may have had considerable impact on prominent middle Carnian events: Reingraben turnover, Carnian Pluvial Event, Carnian Crisis and Mid Carnian Wet Intermezzo. The broad circum-Tethyan evidence of 106-year scale cycles suggests glacioeustatic sea-level changes even in the Triassic Greenhouse period.

Uplift of quaternary shorelines in eastern Patagonia: Darwin revisited

NASA Astrophysics Data System (ADS)

Pedoja, Kevin; Regard, Vincent; Husson, Laurent; Martinod, Joseph; Guillaume, Benjamin; Fucks, Enrique; Iglesias, Maximiliano; Weill, Pierre

2011-04-01

During his journey on the Beagle, Darwin observed the uniformity in the elevation of coastal Eastern Patagonia along more than 2000 km. More than one century later, the sequences of Quaternary shorelines of eastern Patagonia have been described and their deposits dated but not yet interpreted in terms of geodynamics. Consequently, we i) mapped the repartition of the Quaternary coastal sequences in Argentinean Patagonia, ii) secured accurate altitudes of shoreline angles associated with erosional morphologies (i.e. marine terraces and notches), iii) took into account previous chrono-stratigraphical interpretations in order to calculate mean uplift rates since ~ 440 ka (MIS 11) and proposed age ranges for the higher and older features (up to ~ 180 m), and iv) focused on the Last Interglacial Maximum terrace (MIS 5e) as the best constrained marine terrace (in terms of age and altitude) in order to use it as a tectonic benchmark to quantify uplift rates along the entire passive margin of Eastern South America. Our results show that the eastern Patagonia uplift is constant through time and twice the uplift of the rest of the South American margin. We suggest that the enhanced uplift along the eastern Patagonian coast that interested Darwin during his journey around South America on the Beagle could originate from the subduction of the Chile ridge and the associated dynamic uplift.

Seismic stratigraphic characteristics of upper Louisiana continental slope: an area east of Green Canyon

USGS Publications Warehouse

Bouma, Arnold H.; Feeley, Mary H.; Kindinger, Jack G.; Stelting, Charles E.; Hilde, Thomas W.C.

1981-01-01

A high-resolution seismic reflection survey was conducted in a small area of the upper Louisiana Continental Slope known as Green Canyon Area. This area includes tracts 427, 428, 471, 472, 515, and 516, that will be offered for sale in March 1982 as part of Lease Sale 67.The sea floor of this region is, slightly hummocky and is underlain by salt diapirs that are mantled by early Tertiary shale. Most of the shale is overlain by younger Tertiary and Quaternary deposits, although locally some of the shale protrudes the sea floor. Because of proximity to older Mississippi River sources, the sediments are thick. The sediment cover shows an abundance of geologic phenomena such as horsts, grabens, growth faults, normal faults, and consolidation faults, zones with distinct and indistinct parallel reflections, semi-transparent zones, distorted zones, and angular unconformities.The major feature of this region is a N-S linear zone of uplifted and intruded sedimentary deposits formed due to diapiric intrusion.Small scale graben development over the crest of the structure can be attributed to extension and collapse. Large scale undulations of reflections well off the flanks of the uplifted structure suggest sediment creep and slumping. Dipping of parallel reflections show block faulting and tilting.Air gun (5 and 40 cubic inch) records reveal at least five major sequences that show masked onlap and slumping in their lower parts grading into more distinct parallel reflections in their upper parts. Such sequences can be related to local uplift and sea level changes. Minisparker records of this area show similar sequences but on a smaller scale. The distinct parallel reflections often onlap the diapir flanks. The highly reflective parts of these sequences may represent turbidite-type deposition, possibly at times of lower sea level. The acoustically more transparent parts of each sequence may represent deposits containing primarily hemipelagic and pelagic sediment.A complex ridge system is present along the west side of the area and distinct parallel reflections onlap onto this structure primarily from the east. Much of this deposition may be ascribed to sedimentation within a submarine canyon whose position is controlled by this ridge.

Stratigraphy and Age of Paleoproterozoic Birimian Volcaniclastic Sequence in the Cape Three Points area, Axim-Konongo (Ashanti) Belt, Southwest Ghana

NASA Astrophysics Data System (ADS)

Yoshimaru, S.; Kiyokawa, S.; Ito, T.; Ikehara, M.; Horie, K.; Takehara, M.; Sano, T.; Nyame, F. K.; Tetteh, G. M.

2016-12-01

This study investigated the depositional environments and bioactivities of well preserved volcaniclastic sequences in the Cape Three Points area in the Paleoproterozoic Axim-Konongo (Ashanti) belt in the Birimian of Ghana. Our current research outlines the stratigraphy, structure, approximate age and depositional setting of the volcaniclastic sequence in the Cape Three Points area in Ghana, West Africa.Axim-Konongo (Ashanti) belt is composed of mainly andesitic basalts, volcaniclastic rocks and belt type granitoids, which are unconformably overlain by Tarkwaian conglomerates and metasedimentary rocks. The rocks show NE-SW strike with maximum depositional age of overlying metasedimentary rocks of 2154±2 Ma (U-Pb zircon; Oberthür et al., 1998). The oldest age of an intrusive into Birimian volcanic rock near Sekondi is 2174±2 Ma (U-Pb zircon; Oberthür et al., 1998). Thick volcaniclastic succession over 4000 m thickness was reconstructed for 1000 m thickness after detailed field investigations. The succession shows approximately N-S strike mainly 60-80° dip to the east and generally upward sequence. The rocks were affected by greenschist facies metamorphism. TiO2/Al2O3 ratios of chromites and whole- rock trace elements compositions with low Nb concentration and high LREE concentration support deposition on mid-deep sea floor in a volcanic arc. New age data were obtained from foliated porphyritic dyke which occurs in the Cape Three Points area. Zircon grains, measured by SHRIMP at National Institute of Polar Research (NIPR), yielded a weighted mean 204Pb-corrected 207Pb/206Pb age of 2265.6±4.6 Ma (95% confidence). Thus, the volcaniclastic sequence was deposited before 2265.6±4.6 Ma and was deformed after 2265 Ma. 2260 Ma is the oldest age at which early volcanic activity in the Birimian terrane occurred (Loh and Hirdes, 1999). References Oberthür T et al. (1998) Precambrian Research 89: 129-143 Loh G and Hirdes W (1999) Exlplanatory Notes for the Geological Map of southwest Ghana, 1:100000. Ghana Geological Survey Bulletin No, 49, 106-112

The Inskip Formation, the Harmony Formation, and the Havallah Sequence of Northwestern Nevada - An Interrelated Paleozoic Assemblage in the Home of the Sonoma Orogeny

USGS Publications Warehouse

Ketner, Keith B.

2008-01-01

An area between the towns of Winnemucca and Battle Mountain in northwestern Nevada, termed the arkosic triangle, includes the type areas of the middle to upper Paleozoic Inskip Formation and Havallah sequence, the Upper Devonian to Mississippian Harmony Formation, the Sonoma orogeny, and the Golconda thrust. According to an extensive body of scientific literature, the Havallah sequence, a diverse assemblage of oceanic rocks, was obducted onto the continent during the latest Permian or earliest Triassic Sonoma orogeny by way of the Golconda thrust. This has been the most commonly accepted theory for half a century, often cited but rarely challenged. The tectonic roles of the Inskip and Harmony Formations have remained uncertain, and they have never been fully integrated into the accepted theory. New, and newly interpreted, data are incompatible with the accepted theory and force comprehensive stratigraphic and tectonic concepts that include the Inskip and Harmony Formations as follows: middle to upper Paleozoic strata, including the Inskip, Harmony, and Havallah, form an interrelated assemblage that was deposited in a single basin on an autochthonous sequence of Cambrian, Ordovician, and lowest Silurian strata of the outer miogeocline. Sediments composing the Upper Devonian to Permian sequence entered the basin from both sides, arkosic sands, gravel, limestone olistoliths, and other detrital components entered from the west, and quartz, quartzite, chert, and other clasts from the east. Tectonic activity was expressed as: (1) Devonian uplift and erosion of part of the outer miogeocline; (2) Late Devonian depression of the same area, forming a trough, probably fault-bounded, in which the Inskip, Harmony, and Havallah were deposited; (3) production of intraformational and extrabasinal conglomerates derived from the basinal rocks; and (4) folding or tilting of the east side of the depositional basin in the Pennsylvanian. These middle to upper Paleozoic deposits were compressed in the Jurassic, causing east-verging thrusts in the eastern part of the depositional basin (Golconda thrust) and west-verging thrusts and folds in the western part. Hypotheses involving a far-traveled allochthon that was obducted from an ocean or back-arc basin are incompatible with modern observations and concepts.

Transient phases during crystallization of solution-processed organic thin films

NASA Astrophysics Data System (ADS)

Wan, Jing; Li, Yang; Ulbrandt, Jeffery; Smilgies, Detlef-M.; Hollin, Jonathan; Whalley, Adam; Headrick, Randall

We report an in-situ study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic semiconductor thin film deposition from solution via hollow pen writing, which exhibits multiple transient phases during crystallization. Under high writing speed (25 mm/s) the films have an isotropic morphology, although the mobilities range up to 3.0 cm2/V.s. To understand the crystallization in this highly non-equilibrium regime, we employ in-situ microbeam grazing incidence wide-angle X-ray scattering combined with optical video microscopy at different deposition temperatures. A sequence of crystallization was observed in which a layered liquid-crystalline (LC) phase of C8-BTBT precedes inter-layer ordering. For films deposited above 80ºC, a transition from LC phase to a transient crystalline state that we denote as Cr1 occurs after a temperature-dependent incubation time, which is consistent with classical nucleation theory. After an additional ~ 0.5s, Cr1 transforms to the final stable structure Cr2. Based on these results, we demonstrate a method to produce large crystalline grain size and high carrier mobility during high-speed processing by controlling the nucleation rate during the transformation from the LC phase. Nsf DMR-1307017, NSF DMR-1332208.

Identifying and Interpreting Stratification in Sedimentary Rocks on Mars: Insight from Rover and Orbital Observations and Terrestrial Field Analogs

NASA Astrophysics Data System (ADS)

Edgar, Lauren A.

Sedimentary rocks on Mars provide insight into past aqueous and atmospheric processes, climate regimes, and potential habitability. The stratigraphic architecture of sedimentary rocks on Mars is similar to that of Earth, indicating that the processes that govern deposition and erosion on Mars can be reasonably inferred through reference to analogous terrestrial systems. This dissertation aims to understand Martian surface processes through the use of (1) ground-based observations from the Mars Exploration Rovers, (2) orbital data from the High Resolution Imaging Science Experiment onboard the Mars Reconnaissance Orbiter, and (3) the use of terrestrial field analogs to understand bedforms and sediment transport on Mars. Chapters 1 and 2 trace the history of aqueous activity at Meridiani Planum, through the reconstruction of eolian bedforms at Victoria crater, and the identification of a potential mudstone facies at Santa Maria crater. Chapter 3 uses Terrestrial Laser Scanning to study cross-bedding in pyroclastic surge deposits on Earth in order to understand sediment transport in these events and to establish criteria for their identification on Mars. The final chapter analyzes stratal geometries in the Martian North Polar Layered Deposits using tools for sequence stratigraphic analysis, to better constrain past surface processes and past climate conditions on Mars.

Geomagnetic Reversals in Neoproterozoic Cap Carbonates and Time Constraints on Snowball Earth Events

NASA Astrophysics Data System (ADS)

Trindade, R. I.; Font, E.; Nedelec, A.

2008-05-01

The end of the Neoproterozoic is characterized by ubiquitous glacial deposition being followed by the onset of extensive carbonate platforms, marking important changes in climate. The duration of these climatic oscillations is still poorly constrained with estimates varying from hundreds to hundreds of thousand years. Here we report a high-resolution magnetostratigraphic study of Neoproterozoic cap carbonates from the Amazon Craton. These rocks represent the first transgressive carbonate sequence after glacial deposits and present the isotopic signatures and sedimentary structures that typify cap carbonates elsewhere in the world, such as negative delta13C values, tubes, aragonite-pseudomorph crystal fans, pseudo-tepees (megaripples). Age constraints are given by shifts in 87Sr/86Sr ratios towards values greater than 0.7081 and by a Pb-Pb age of 627 ± 32 Ma. Two sections five kilometers apart were sampled with a 20 cm spacing (=101 sites) and revealed five coherent reversals. Magnetization is carried by detrital hematite. These data were used to constrain both the paleogeographic position of the Amazon Craton by the end of Neoproterozoic glaciations, and the time of cap carbonate deposition (in the order of hundreds of thousand years) with implications for geochemical models. Comparison with results from correlative successions in Africa, Oman and Australia will also be presented.

Haematobia irritans dataset of raw sequence reads from Illumina and Pac Bio sequencing of genomic DNA

USDA-ARS?s Scientific Manuscript database

The genome of the horn fly, Haematobia irritans, was sequenced using Illumina- and Pac Bio-based protocols. Following quality filtering, the raw reads have been deposited at NCBI under the BioProject and BioSample accession numbers PRJNA30967 and SAMN07830356, respectively. The Illumina reads are un...

Shallow-seated explosions in the construction of the Motukorea tuff ring (Auckland, New Zealand): Evidence from lithic and sedimentary characteristics

NASA Astrophysics Data System (ADS)

Agustín-Flores, Javier; Németh, Károly; Cronin, Shane J.; Lindsay, Jan M.; Kereszturi, Gábor

2015-10-01

At least 52 eruption centres are scattered within the 360 km2 Auckland Volcanic Field (AVF). Motukorea, now an island in the Waitemata Harbour, is one of 39 AVF volcanoes that experienced a phreatomagmatic explosive phase, before a magmatic phase. The volcano erupted through a 200-300 m-thick, consolidated, mudstone/sandstone sequence of the Miocene Waitemata Group, which overlies the Waipapa Terrane greywacke basement. Detailed field descriptions of the sedimentary characteristics of the early phreatomagmatic deposits were carried out, along with examination of lithics. The ejecta ring deposit comprises 55 to 60 vol.% lithics, of which Waitemata Group fragments constitute approximately 90 vol.%, whereas < 10 vol.% are Waipapa fragments, suggesting a dominance of shallow fragmentation. The sedimentary characteristics of the stratigraphic sequence at Motukorea suggest a dominance of wet surges at the beginning of the eruption with progression into drier sequences upwards. This is reflected in increasing inter-bedded juvenile-pyroclast-dominated fall deposits up-sequence. These characteristics are attributed to the changing hydrogeological conditions within the diatreme and the host rocks. These findings shed light on the eruption dynamics of phreatomagmatic eruptions through consolidated rocks in the AVF and enable the depiction of a scenario of future eruptions within the field in similar substrates.

39 CFR 3005.21 - Authority to order depositions and responses to written interrogatories.

Code of Federal Regulations, 2010 CFR

2010-07-01

... written interrogatories. 3005.21 Section 3005.21 Postal Service POSTAL REGULATORY COMMISSION PERSONNEL PROCEDURES FOR COMPELLING PRODUCTION OF INFORMATION BY THE POSTAL SERVICE Depositions and Written Interrogatories § 3005.21 Authority to order depositions and responses to written interrogatories. The Chairman...

Micromorphological aspects of various human activities recorded in the Scafati pedocomplex (Napoli, Italy).

NASA Astrophysics Data System (ADS)

Rellini, Ivano; Vogel, Sebastian; Märker, Michael

2014-05-01

The stratigraphic sequence of Scafati, about 3 km east of ancient Pompeii, is presented consisting of a multilayered sequence of repeated volcanic deposition and pedogenesis that was caused by several phases of volcanic activity and volcanic quiescence of Somma-Vesuvius, at least, the last 20,000 years. Micromorphological analysis were carried out at the soil material and selected volcanic deposits to establish a chronological succession of different phases of volcanic deposition, pedogenetic transformation but also to highlight the anthropogenic influence. The micromorphological analysis testified furrow irrigation and soil cultivation in the medieval stratigraphy and allowed the identification of very significant antropogenic features in the Bronze Age/Iron Age paleosol, i.e. complex depositional crusts and dusty clay coatings and hypocoatings, which are often used as an indicator for tillage activity. In contrast to the clear macroscopic and chemical evidence of ancient soil cultivation, the Roman paleosol did not exhibit distinct micromorphological signs of soil cultivation.

Geochemical Peculiarities of Galena and Sphalerite from Polymetallic Deposits of the Dal'negorskii Ore Region (Primorsky Krai, Russia)

NASA Astrophysics Data System (ADS)

Rogulina, L. I.; Moiseenko, V. G.; Ponomarchuk, V. A.

2018-04-01

New data on the composition of the major minerals from the skarn and vein polymetallic deposits of the Dal'negorskii ore region are reported. Analysis of galena and sphalerite was carried out by the X-ray fluorescent energy-dispersive method of synchrotron radiation for the first time. It is shown that the minor elements in major minerals of different deposits are typomorphic. Among these elements are Fe, Cu, Ni, Cd, Ag, Sn, and Sb, as well as In in sphalerite and Te in galena. The high concentrations of Ag, Cu, Te, Cd, and In in the extracted minerals indicate the complex character of mineralization. The compositional patterns of ore minerals characterize the sequence of mineral formation from the skarn to vein ores, and the sequence of deposits from the mesothermal to epithermal conditions. This provides geochemical evidence for the stage model of the formation of mineralization in the Dal'negorskii ore region.

Stratigraphic and facies analysis of Ste. Genevieve Limestone, Putnam County, Indiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevenson, G.M.

1987-05-01

The Ste. Genevieve Limestone (Mississippian) in Putnam County, Indiana, was deposited on a southwestward-sloping ramp in the northeastern portion of the Illinois basin. This portion of the Ste. Genevieve Limestone is divided into three members which, in ascending order, are the Fredonia, the Spar Mountain, and the Levias. The Fredonia Member appears to be homogeneous biomicrite on out-crop, but petrographic analysis reveals mottling and distinguishable pellets and is classified as pelbiosparite. Storm deposits are observed and typically are composed of fossil hash zones (biopelsparite) overlain by calcitic shale layers. Bioclasts consist of stenohaline forms with foraminifera, echinoderms, and bryozoans predominant.more » The gray-green shale layers represent punctuated terrigenous influx in this shallow restricted shelf. The Spar Mountain Member is commonly cross-bedded calcarenite but commonly lacks the quartz and is oolitic-pelbiosparite. The dominant particle types are quartz-centered ooids, peloids, and echinoderm fragments. Relatively high energy conditions and herringbone-cross-beds suggest deposition of a shoal with tidal current influence. The Levias Member is thin-bedded biopelsparite which represents shallow shelf deposition. The Bryantsville Breccia Bed varies in thickness across the study area and marks the top of the Levias Member. Oolitic-biopelsparite centimeter-sized clasts are contained in a matrix of similar material, suggesting an intraformational mode of origin, possibly a collapse breccia. Two incomplete shoaling-upward cycles are present in this Ste. Genevieve sequence. The lower portion of each cycle is pelbiosparite/biopelsparite overlain by oolitic-pelbiosparite and/or calcarenite.« less

Lithofacies, Age, and Sequence Stratigraphy of the Carboniferous Lisburne Group in the Skimo Creek Area, Central Brooks Range

USGS Publications Warehouse

Dumoulin, Julie A.; Whalen, Michael T.; Harris, Anita G.

2008-01-01

The Lisburne Group, a mainly Carboniferous carbonate succession that is widely distributed across northern Alaska, contains notable amounts of oil and gas at Prudhoe Bay. Detailed studies of the Lisburne in the Skimo Creek area, central Brooks Range, delineate its lithofacies, age, conodont biofacies, depositional environments, and sequence stratigraphy and provide new data on its hydrocarbon source-rock and reservoir potential, as well as its thermal history, in this area. We have studied the Lisburne Group in two thrust sheets of the Endicott Mountains allochthon, herein called the Skimo and Tiglukpuk thrust sheets. The southern, Skimo Creek section, which is >900 m thick, is composed largely of even-bedded to nodular lime mudstone and wackestone intercalated with intervals of thin- to thick-bedded bioclastic packstone and grainstone. Some parts of the section are partially to completely dolomitized and (or) replaced by chert. A distinctive, 30-m-thick zone of black, organic-rich shale, lime mudstone, and phosphorite is exposed 170 m below the top of the Lisburne. The uppermost 40 m of section is also distinctive and made up of dark shale, lime mudstone, spiculite, and glauconitic grainstone. The northern, Tiglukpuk Creek section, which is similar to the Skimo Creek section but only ~760 m thick, includes more packstone and grainstone and less organic-rich shale. Analyses of conodonts and foraminifers indicate that both sections range in age from late Early Mississippian (Osagean) through Early Pennsylvanian (early Morrowan) and document a hiatus of at least 15 m.y. at the contact between the Lisburne and the overlying Siksikpuk Formation. No evidence of subaerial exposure was observed along this contact, which may represent a submarine erosional surface. Lithofacies and biofacies imply that the Lisburne Group in the study area was deposited mainly in midramp to outer-ramp settings. Deepest water strata are mud rich and formed below storm or fair-weather wave base on the outer ramp to outer midramp; shallowest facies are storm, sand-wave, and shoal deposits of the inner midramp to inner ramp. A relatively diverse, open-marine fauna occurs throughout much of the Lisburne in the study area, but some beds also contain clasts typical of more restricted, shallow-water environments that were likely transported seaward by storms and currents. Radiolarians are abundant in the shale and phosphorite unit at Skimo Creek and also occur in equivalent strata at Tiglukpuk Creek; high gamma-ray response and elevated total organic-carbon contents (max 5?8 weight percent) also characterize this unit at Skimo Creek. Lithologic, faunal, and geochemical data all suggest that these rocks formed mainly in an outer-ramp to basinal setting with low sedimentation rates, high productivity, and poorly oxygenated bottom water. Shale and mudstone at the top of the Lisburne Group accumulated in a similarly sediment starved, mainly outer ramp environment but lack comparable evidence for high nutrient and low oxygen levels during deposition. Vertical shifts in rock types and faunas delineate numerous parasequences and six probable third-order sequences in the study area; the same sequences are also recognized in the Lisburne Group to the east. Transgressive-system tracts in these sequences generally fine upward, whereas highstand-system tracts coarsen upward. Sequences in the Tiglukpuk Creek section are mostly thinner, contain thinner and more numerous parasequences, and accumulated in somewhat shallower settings than those in the Skimo Creek section. These differences reflect the more seaward position and, thus, increased accommodation space of the Skimo Creek section relative to the Tiglukpuk Creek section during deposition. Organic-rich calcareous shale in the shale and phosphorite unit has a cumulative thickness of at least 15 m and a lateral extent of >50 km; this lithology is the best potential hydrocarbon source rock in the Lisburne Group

Sequence Stratigraphic Analysis and Facies Architecture of the Cretaceous Mancos Shale on and Near the Jicarilla Apache Indian Reservation, New Mexico-their relation to Sites of Oil Accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ridgley, Jennie

2001-08-21

The purpose of phase 1 and phase 2 of the Department of Energy funded project Analysis of oil- bearing Cretaceous Sandstone Hydrocarbon Reservoirs, exclusive of the Dakota Sandstone, on the Jicarilla Apache Indian Reservation, New Mexico was to define the facies of the oil producing units within the Mancos Shale and interpret the depositional environments of these facies within a sequence stratigraphic context. The focus of this report will center on (1) redefinition of the area and vertical extent of the ''Gallup sandstone'' or El Vado Sandstone Member of the Mancos Shale, (2) determination of the facies distribution within themore » ''Gallup sandstone'' and other oil-producing sandstones within the lower Mancos, placing these facies within the overall depositional history of the San Juan Basin, (3) application of the principals of sequence stratigraphy to the depositional units that comprise the Mancos Shale, and (4) evaluation of the structural features on the Reservation as they may control sites of oil accumulation.« less

Lithostratigraphy and depositional environments of the Upper Jurassic Arab-C carbonate and associated evaporites in the Abqaiq Field, eastern Saudi Arabia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saner, S.; Abdulghani, W.M.

1995-03-01

Lithostratigraphy and depositional environment of the Arab-C carbonate in eastern Saudi Arabia were studied using cores and well logs from the Abqaiq oil field. A 275-m Upper Jurassic evaporite sequence occurs between the Sulaiy-Yamama (Thamama Group) and the Tuwaiq-Hanifa-Arab-D (Tuwaiq Group) carbonate sequences. Dolomite and limestone interbeds of 1-30 m in thickness within the evaporite sequence are continuous over long distances and have uniform thicknesses and log characteristics indicating an aggradational type of deposition. The lithologically heterogeneous Arab-C carbonate is the thickest interbed, reaching 26-30 m in thickness. Lithology types recognized in the Arab-C carbonate are (1) ooid bioclast grainstone,more » (2) oolite grainstone, (3) pellet grainstone, (4) pellet packstone, (5) skeletal wackestone, (6) mudstone, (7) anhydritic limestone, and (8) dolomite. The Arab-C carbonate has been divided into seven layers based on lithology and porosity variations. Four layers (1,3,5,7) are porous calcarenitic carbonates and the other three layers are nonporous.« less

Curated eutherian third party data gene data sets.

PubMed

Premzl, Marko

2016-03-01

The free available eutherian genomic sequence data sets advanced scientific field of genomics. Of note, future revisions of gene data sets were expected, due to incompleteness of public eutherian genomic sequence assemblies and potential genomic sequence errors. The eutherian comparative genomic analysis protocol was proposed as guidance in protection against potential genomic sequence errors in public eutherian genomic sequences. The protocol was applicable in updates of 7 major eutherian gene data sets, including 812 complete coding sequences deposited in European Nucleotide Archive as curated third party data gene data sets.

Across the Gap: Geochronological and Sedimentological Analyses from the Late Pleistocene-Holocene Sequence of Goda Buticha, Southeastern Ethiopia

PubMed Central

Asrat, Asfawossen; Bahain, Jean-Jacques; Chapon, Cécile; Douville, Eric; Fragnol, Carole; Hernandez, Marion; Hovers, Erella; Leplongeon, Alice; Martin, Loïc; Pleurdeau, David; Pearson, Osbjorn; Puaud, Simon; Assefa, Zelalem

2017-01-01

Goda Buticha is a cave site near Dire Dawa in southeastern Ethiopia that contains an archaeological sequence sampling the late Pleistocene and Holocene of the region. The sedimentary sequence displays complex cultural, chronological and sedimentological histories that seem incongruent with one another. A first set of radiocarbon ages suggested a long sedimentological gap from the end of Marine Isotopic Stage (MIS) 3 to the mid-Holocene. Macroscopic observations suggest that the main sedimentological change does not coincide with the chronostratigraphic hiatus. The cultural sequence shows technological continuity with a late persistence of artifacts that are usually attributed to the Middle Stone Age into the younger parts of the stratigraphic sequence, yet become increasingly associated with lithic artifacts typically related to the Later Stone Age. While not a unique case, this combination of features is unusual in the Horn of Africa. In order to evaluate the possible implications of these observations, sedimentological analyses combined with optically stimulated luminescence (OSL) were conducted. The OSL data now extend the radiocarbon chronology up to 63 ± 7 ka; they also confirm the existence of the chronological gap between 24.8 ± 2.6 ka and 7.5 ± 0.3 ka. The sedimentological analyses suggest that the origin and mode of deposition were largely similar throughout the whole sequence, although the anthropic and faunal activities increased in the younger levels. Regional climatic records are used to support the sedimentological observations and interpretations. We discuss the implications of the sedimentological and dating analyses for understanding cultural processes in the region. PMID:28125597

Across the Gap: Geochronological and Sedimentological Analyses from the Late Pleistocene-Holocene Sequence of Goda Buticha, Southeastern Ethiopia.

PubMed

Tribolo, Chantal; Asrat, Asfawossen; Bahain, Jean-Jacques; Chapon, Cécile; Douville, Eric; Fragnol, Carole; Hernandez, Marion; Hovers, Erella; Leplongeon, Alice; Martin, Loïc; Pleurdeau, David; Pearson, Osbjorn; Puaud, Simon; Assefa, Zelalem

2017-01-01

Goda Buticha is a cave site near Dire Dawa in southeastern Ethiopia that contains an archaeological sequence sampling the late Pleistocene and Holocene of the region. The sedimentary sequence displays complex cultural, chronological and sedimentological histories that seem incongruent with one another. A first set of radiocarbon ages suggested a long sedimentological gap from the end of Marine Isotopic Stage (MIS) 3 to the mid-Holocene. Macroscopic observations suggest that the main sedimentological change does not coincide with the chronostratigraphic hiatus. The cultural sequence shows technological continuity with a late persistence of artifacts that are usually attributed to the Middle Stone Age into the younger parts of the stratigraphic sequence, yet become increasingly associated with lithic artifacts typically related to the Later Stone Age. While not a unique case, this combination of features is unusual in the Horn of Africa. In order to evaluate the possible implications of these observations, sedimentological analyses combined with optically stimulated luminescence (OSL) were conducted. The OSL data now extend the radiocarbon chronology up to 63 ± 7 ka; they also confirm the existence of the chronological gap between 24.8 ± 2.6 ka and 7.5 ± 0.3 ka. The sedimentological analyses suggest that the origin and mode of deposition were largely similar throughout the whole sequence, although the anthropic and faunal activities increased in the younger levels. Regional climatic records are used to support the sedimentological observations and interpretations. We discuss the implications of the sedimentological and dating analyses for understanding cultural processes in the region.

Annual dynamics of halite precipitation in the Dead Sea: In situ observations and their geological implications

NASA Astrophysics Data System (ADS)

Sirota, Ido; enzel, Yehouda; Lensky, Nadav G.

2017-04-01

Layered halite sequences deposited in deep basins throughout the geological record. However, analogues of such sequences are commonly studied in sallow environments. Here we study active precipitation of halite layers from the only modern analog for deep, halite-precipitating basin, the hypersaline Dead Sea. In situ observations in the Dead Sea link seasonal thermohaline stratification, halite saturation, and the characteristics of the actively forming halite layers. The spatiotemporal evolution of halite precipitation in the Dead Sea was characterized by means of monthly observations of the i) lake thermohaline stratification (temperature, salinity, and density), ii) degree of halite saturation, and iii) textural evolution of the active halite deposits. We present the observed relationships between textural characteristics of layered halite deposits (i.e. grain size, consolidation, and roughness) and the degree of saturation, which in turn reflected the limnology and hydro-climatology. The lakefloor is divided into two principle environments: A deep, hypolimnetic and a shallow, epilimnetic lakefloor. In the deeper hypolimnetic lakefloor halite continuously precipitates with seasonal variations: (a) during summer, consolidated coarse halite crystals form rough surfaces under slight super-saturation. (b) During winter, unconsolidated, fine halite crystals form smooth seafloor deposits under high supersaturation. The observations also emphasize the thought regarding seasonal alternation of halite crystallization mechanism. The shallow epilimnetic lake floor is highly influenced by the seasonal temperature variations, and by intensive summer dissolution of part of the previous year's halite deposit which results in thin sequences with annual unconformities. This emphasizes the control of temperature seasonality on the precipitated halite layers characteristics. In addition, precipitation of halite in the hypolimnetic floor, on the expense of the dissolution of the epilimnetic floor, results in lateral focusing and thickening of halite deposit in the deeper part of the basin and thinning of the deposits in shallow marginal basins.

An algorithm to compute the sequency ordered Walsh transform

NASA Technical Reports Server (NTRS)

Larsen, H.

1976-01-01

A fast sequency-ordered Walsh transform algorithm is presented; this sequency-ordered fast transform is complementary to the sequency-ordered fast Walsh transform introduced by Manz (1972) and eliminating gray code reordering through a modification of the basic fast Hadamard transform structure. The new algorithm retains the advantages of its complement (it is in place and is its own inverse), while differing in having a decimation-in time structure, accepting data in normal order, and returning the coefficients in bit-reversed sequency order. Applications include estimation of Walsh power spectra for a random process, sequency filtering and computing logical autocorrelations, and selective bit reversing.

The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary

USGS Publications Warehouse

Riehle, J.R.; Mann, D.H.; Peteet, D.M.; Engstrom, D.R.; Brew, D.A.; Meyer, C.E.

1992-01-01

Late Pleistocene tephra deposits found from Sitka to Juneau and Lituya Bay are assigned to a source at the Mount Edgecumbe volcanic field, based on similarity of glass compositions to nearvent deposits and on thinning away from Kruzof Island. The sequence of near-vent layers is basaltic andesite and andesite at the base, rhyolite, and mixed dacite and rhyolite on top. The only breaks in the tephra sequence are two 1-mm-thick silt partings in a lake-sediment core, indicating a depositional interval from basaltic andesite to dacite of no more than about a millennium. Tephra deposits at sites >30 km from the vent are solely dacite and rhyolite and are 10,600 to 11,400 14C yr old based on interpretation of 18 radiocarbon ages, including 5 by accelerator mass spectrometry (AMS). Basaltic andesite and andesite deposits nearer the vent are as much as 12,000 yr old. Discrepancy among radiocarbon ages of upland tephra deposits provisionally correlated as the same grainfall is resolvable within ??2 ?? of analytical uncertainty. Comparison of bulk and AMS ages in one sediment core indicates a systematic bias of +600 to +1100 yr for the bulk ages; correlation of tephra deposits among upland and lacustrine sites implies an additional discrepancy of 200-400 yr between upland (relatively too young) and lacustrine ages. In any case, the Mount Edgecumbe tephra deposits are a widespread, latest Pleistocene stratigraphic marker that serves to emphasize the uncertainty in dating biogenic material from southeastern Alaska. ?? 1992.

Stratigraphic architecture and depositional history of lower Miocene, Planulina Zone, Southern Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gates, B.C.; Galloway, W.E.

1988-01-01

The Planulina zone is a wedge of clastic sediment positioned between the Anahuac shale below and the Oakville sandstone interval above. Planulna sediments were deposited on an erosional surface, during a general rise in the sea level, and formed a retrogradational wedge. Within the study area, the Planulina zone consists of two large depositional complexes: the Mud Lake complex in west Cameron Parish, Louisiana, and the East Cameron complex in east Cameron Parish. The lowermost depositional sequence in the East Cameron complex is preserved in a network of submarine canyons that were eroded into the upper slope. Framework sands weremore » deposited in channel systems confined to the axis of the canyons, and the sands are encased in marine shale containing benthonic foraminifera indicative of an upper to middle slope paleoenvironment. Two younger depositional sequences overlie the submarine canyon facies and were deposited by deltaic systems that prograded basinward. A zone of expansion extends east to west through the Planulina interval and is named the ''Planulina flexure.'' The flexure is a large fault located at the relict shelf edge and soles out downdip inn the Anahuac shale. Several thousand feet of sediment downthrown on the flexure is equivalent to several hundred feet upthrown, and the flexure represented the boundary dividing updip deltaic processes from downdip slope processes during the beginning of Planulina deposition. The Planulina depositional history and stratigraphic architecture are directly related to the displacement along the flexure and the structural deformation of the underlying Anahuac shale.« less

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

NASA Astrophysics Data System (ADS)

Smith, Christopher N.; Kesler, Stephen E.; Blum, Joel D.; Rytuba, James J.

2008-05-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300 m) and silica-carbonate deposits that extend to depths of 1000 m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions ( δ202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although δ202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean δ202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ± 0.5‰) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO 2 vapor or reduction and volatilization of Hg (0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low δ202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

USGS Publications Warehouse

Smith, C.N.; Kesler, S.E.; Blum, J.D.; Rytuba, J.J.

2008-01-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300??m) and silica-carbonate deposits that extend to depths of 1000??m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions (??202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although ??202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean ??202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ?? 0.5???) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO2 vapor or reduction and volatilization of Hg(0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low ??202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems. ?? 2008 Elsevier B.V. All rights reserved.

Late Cretaceous base level lowering in Campanian and Maastrichtian depositional sequences, Kure Beach, North Carolina

USGS Publications Warehouse

Harris, W.B.; ,

2006-01-01

Campanian through Maastrichtian mixed carbonate and siliciclastic sediments in a 422 m continuous core drilled at Kure Beach, NC provide a record of sea-level change. Based on lithology and stratigraphy, depositional sequences are defined, and calcareous nannofossil zones and 87Sr/86Sr ratios and corresponding ages using the LOWESS Table determined. Campanian and Maastrichtian sediments comprise six depositional sequences. The oldest is Tar Heel 1 and contains calcareous nannofossils that indicate assignment to the upper part of Zones CC18a, CC18c and the lower part of CC19. 87Sr/86 Sr ratios indicate ages from 83.2 to 80.0 Ma or lower Campanian. Tar Heel II contains calcareous nannofossils that indicate assignment to the upper part of Zone CC 19 and CC20. 87Sr/86Sr ratios indicate ages from 78.0 to 76.3 Ma or middle Campanian. Donoho Creek I and II are thin and contain calcareous nannofossils referable to upper Zone CC21 and Zone CC22, and to CC23, respectively. The top of Donoho Creek II marks the Campanian-Maastrichtian boundary. Donoho Creek I 87Sr/86Sr ratios cluster into two groups, and provide ages from 78.0 to 76.2 Ma and 73.7 to 72.3 Ma, respectively. 87Sr/86Sr ratios in Donoho Creek II indicate ages from 71.4 to 69.6 Ma. Two Maastrichtian sequences are present; the lowermost Peedee I contains calcareous nannofossils that place it in Zones CC25a and CC25b. 87Sr/86Sr r ratios indicate an age from 69.3 to 66.9 Ma or late Maastrichtian. Peedee II is assigned to calcareous nannofossil Zone CC26a. 87Sr/86Sr ratios indicate ages from 66.4 to 65.2 Ma or late Maastrichtian. The four Campanian sequences correlate to three depositional sequences in New Jersey; the sequence boundary between upper Campanian Donoho Creek I and Donoho Creek II is not recognized in New Jersey. This boundary is interpreted to result from Gulf Stream impingement and subsequent erosion on the outer shelf. The two Maastrichtian sequences recognized in the Kure Beach core correlate to the two identified Maastrichtian sequences in New Jersey. These data support base-level lowering of sea-level during the Campanian-Maastrichtian, and suggest that the western margin of the North Atlantic may contain one of the best Late Cretaceous records of sea-level change.

A Study of the Magnetic Fingerprint of Tsunami Induced Deposits in the Ixtapa-Zihuatanejo Area (Western Mexico)

NASA Astrophysics Data System (ADS)

Goguitchaichrili, A.; Ramirez-Herrera, M.; Calvo-Rathert, M.; Aguilar, B.; Carrancho, Alonso; Morales, J.; Caballero, C. I.; Bautista, F.

2013-05-01

The Pacific coast of Mexico has repeatedly been exposed to destructive tsunamis. Recent studies have shown that rock-magnetic methods can be a promising approach for identification of tsunami or storm induced deposits. We present new rock-magnetic and anisotropy of magnetic susceptibility results to try to distinguish tsunami deposits in the Ixtapa-Zihuatanejo area (Western Mexico). The sampled, 80 cm deep sequence is characterised by the presence of two anomalous sand beds within fine-grained coastal deposits. The first lower lying sand bed is probably associated with the 14th March 1979 Petatlán earthquake (MW = 7.6) while the second one was originated by the September 21st 1985 Mexico earthquake (MW = 8.1). Rock magnetic experiments have shown significant variations within the analysed sequence. Thermomagnetic curves reveal two types of behaviour: In the upper part of the sequence, after the occurrence of the first tsunami and in the lower part of the sequence, during that event and below. Analysis of hysteresis parameter ratios in a Day-plot also allows distinguishing two kinds of behaviour. The samples associated to the second tsunami plot in the PSD area, while specimens associated to the first tsunami and the time between both tsunamis display a very different trend which can be ascribed to the production of a considerable amount of superparamagnetic grains which might be due to pedogenic processes after the first tsunami. The studied profile is characterised by a sedimentary fabric with almost vertical minimum principal susceptibilities. The maximum susceptibility axis shows a declination angle D = 27, suggesting a NNE flow direction which is equal for both tsunamis and normal currents. The standard AMS parameters display a significant enhancement within the transitional zone between both tsunamis. The study of rock-magnetic parameters may represent a useful tool for the identification and understanding of tsunami deposits.

Geology and mineral deposits of the Hekimhan-Hasancelebi iron district, Turkey

USGS Publications Warehouse

Jacobson, Herbert S.; Kendiro'glu, Zeki; ,; Celil, Bogaz; ,; Onder, Osman; Gurel, Nafis

1972-01-01

An area of 210 sq km was investigated in the Hekimhan-Hasancelebi district. of central Turkey as part of the Maden Tetkik ve Arama Institusu(MTA)-U. S. Geological Survey(USGS) mineral exploration and training project to explore for iron deposits and to provide on-.the-job training for MTA geologists. The rocks of the area are Cretaceous and Tertiary sedimentary and volcanic rocks intruded by syenite and a serpentinized mafic and ultramafic complex and overlain unconformably by late .Tertiary basalt. The base of the section is a thick mafic volcanic-sedimentary sequence with diverse rocks that include conglomerate, sandstone, shale, tuff, limestone, and basalt. The upper part of the sequence is metasomatized near syenite contacts. The sequence is conformably overlain by trachyte and unconformably overlain by massive limestone. Overlying the limestone is a Tertiary sedimentary sequence which is dominantly conglomerate and sandstone with local limestone and volcanic rocks. This series is in turn overlain by olivine basalt. Mineral deposits are associated with the two types of intrusive rocks. Hematite-magnetite in the Karakuz mine area and in the Bahcedami-Hasancelebi area is related to the syenite, and siderite in the Deveci mine area is possibly related to the mafic-ultramafic rocks. Significant iron resources are found, only in the Karakuz and Deveci areas. In the Karakuz area disseminations, veins, and replacements consisting of hematite and magnetite are present. Most of the material is low grade. In the Deveci mine area a large deposit of siderite apparently is a replacement of carbonate beds adjacent to serpentinized igneous rock. The upper part of the siderite deposit is weathered and enriched to a mixture of iron and manganese oxides of direct shipping ore grade. Additional investigation of both the Karakuz and .Deveci mine areas is recommended including: 1. A detailed gravity and magnetic survey of part of the Karakuz area. 2. Diamond drilling at both the Karakuz and Deveci areas.

Fabrication of CuInS2-sensitized solar cells via an improved SILAR process and its interface electron recombination.

PubMed

Xu, Xueqing; Wan, Qingcui; Luan, Chunyan; Mei, Fengjiao; Zhao, Qian; An, Ping; Liang, Zhurong; Xu, Gang; Zapien, Juan Antonio

2013-11-13

Tetragonal CuInS2 (CIS) has been successfully deposited onto mesoporous TiO2 films by in-sequence growth of InxS and CuyS via a successive ionic layer absorption and reaction (SILAR) process and postdeposition annealing in sulfur ambiance. X-ray diffraction and Raman measurements showed that the obtained tetragonal CIS consisted of a chalcopyrite phase and Cu-Au ordering, which related with the antisite defect states. For a fixed Cu-S deposition cycle, an interface layer of β-In2S3 formed at the TiO2/CIS interface with suitable excess deposition of In-S. In the meantime, the content of the Cu-Au ordering phase decreased to a reasonable level. These facts resulted in the retardance of electron recombination in the cells, which is proposed to be dominated by electron transfer from the conduction band of TiO2 to the unoccupied defect states in CIS via exponentially distributed surface states. As a result, a relatively high efficiency of ~0.92% (V(oc) = 0.35 V, J(sc) = 8.49 mA cm(-2), and FF = 0.31) has been obtained. Last, but not least, with an overloading of the sensitizers, a decrease in the interface area between the sensitized TiO2 and electrolytes resulted in deceleration of hole extraction from CIS to the electrolytes, leading to a decrease in the fill factor of the solar cells. It is indicated that the unoccupied states in CIS with energy levels below EF0 of the TiO2 films play an important role in the interface electron recombination at low potentials and has a great influence on the fill factor of the solar cells.

A Multi-Proxy Approach to Reconstruct Climate Variability in the Western Mediterranean across the Penultimate and Last Glacial Period

NASA Astrophysics Data System (ADS)

Dixit, Y.; Toucanne, S.; Bonnin, L.; Fontanier, C.; Jouet, G.; Tripati, A. K.

2016-12-01

The Mediterranean as a model miniature ocean is an ideal study area for the links between climate change and anoxia. Organic rich-sapropelic deposits punctuate Quaternary sediments series in the basin. These deposits reveal the occurrence of anoxic conditions during times when the circulation of the Mediterranean ocean was deeply perturbed. The `'Nilotic paradigm' proposes anoxia was a direct result of massive inputs of fresh water from the Nile. It is also possible that these sapropels could occur in response to periods of intense rainfall and riverine discharge on the northern Mediterranean coast. To resolve the sequence of events linked to sapropel deposition in the western Mediterranean, we use a multi-proxy (oxygen and carbon isotopes, benthic foraminifera assemblage and trace element geochemistry of foraminifera calcite) approach to examine sediments from the Tyrhennian Sea off the eastern Corsica margin in order to reconstruct climate variability during the penultimate glacial termination, and we compare results to those for the last glacial period. Our preliminary results show increased abundance of epifaunal and deep infaunal benthic species during MIS 5e ( 122-125 kyr BP), accompanied by a rise in Mg/Ca-based sea surface temperature (SST) using G. bulloides. A sharp decline in SST at 135 kyr BP coincides with Heinrich Stadial 5 in the North Atlantic. We will compare the timing of Mg/Ca-based SST minima and reconstructed water d18O variations to Heinrich Stadials in the North Atlantic in order to infer the mechanisms responsible for cooling in the Tyrrhenian Sea. This analysis should shed light on the proposed atmospheric teleconnection causing cooling of western Mediterranean waters via intensification of the Northern Hemisphere high-latitude wind systems.

Depositional sequences and facies in the Torok Formation, National Petroleum Reserve, Alaska (NPRA)

USGS Publications Warehouse

Houseknecht, David W.; Schenk, Christopher J.

2002-01-01

Brookian turbidites (Cretaceous through Tertiary) have become oil exploration objectives on the NorthSlope of Alaska during the past decade, and it is likely this focus will extend into the National Petroleum Reserve-Alaska (NPRA). A regional grid of 2-D seismic data, sparse well control, and field work in the Brooks Range foothills provide constraints for an ongoing effort to establish a sequence stratigraphic framework for Brookian turbidites in the Torok Formation across NPRA. The Torok Formation and overlying Nanushuk Formation (both mostly Albian) display the overall seismic geometry of bottomset-clinoform-topset strata indicating northeastward migration of a shelf margin. Within bottomset and clinoform strata of the Torok, depositional sequences have been identified that represent four distinct phases of shelf-margin sedimentation. (1) Regression, representing low relative sea level, is characterized by the development of an erosional surface on the shelf and upper slope, and the deposition of turbidite channel deposits on the middle to lower slope and submarine fan deposits at the base of slope. These deposits constitute a lowstand systems tract (LST). (2) Transgression, representing rising relative sea level, is characterized by the deposition of a mudstone drape on the basin floor, slope, and outer shelf. This drape comprises relatively condensed facies that constitute a transgressive systems tract (TST). (3) Aggradation, representing high relative sea level, is characterized by the deposition of relatively thick strata on the outer shelf and moderately thick mudstones on the slope. (4) Progradation, also representing high relative sea level, is characterized by the deposition of relatively thin strata on the outer shelf and very thick mudstones on the slope. Together, deposits of the aggradation and progradation phases constitute a highstand systems tract (HST). Large scale geometries of Torok strata vary across the Colville basin. In southern NPRA, high rates of subsidence accommodated the deposition of a "foredeep clinoform wedge" that contains a high proportion of sand-rich LST deposits. In northern NPRA, lower rates of subsidence favored the accumulation of mud-rich HST deposits. The most favorable stratigraphic trapping geometries in the Torok Formation occur where amalgamated sandstones deposited in turbidite channels incised on the mid- to lower-slope and on the proximal parts of submarine fans during regression (LSTs) are capped by relatively condensed mudstone facies deposited during transgression (TSTs). Common successions observed in Torok cores include a spectrum of slope and turbidite facies. Upper slope facies comprise laminated mudstones and siltstones that locally display evidence of slumping, sliding, and chaotic failure. Lower slope facies comprise heterolithic turbidites at some locations and interlaminated mudstones and thin, very fine-grained sandstones at others. Torok turbidites include amalgamated sandstones deposited in channel systems as well as thin-bedded, widespread sandstones deposited by unconfined flows on lobes or in channel overbank settings. These turbidite facies likely occur in both channel-lobe systems and slope apron systems within the Torok.

The Bouma Sequence and the turbidite mind set

NASA Astrophysics Data System (ADS)

Shanmugam, G.

1997-11-01

Conventionally, the Bouma Sequence [Bouma, A.H., 1962. Sedimentology of some Flysch Deposits: A Graphic Approach to Facies Interpretation. Elsevier, Amsterdam, 168 pp.], composed of T a, T b, T c, T d, and T e divisions, is interpreted to be the product of a turbidity current. However, recent core and outcrop studies show that the complete and partial Bouma sequences can also be interpreted to be deposits formed by processes other than turbidity currents, such as sandy debris flows and bottom-current reworking. Many published examples of turbidites, most of them hydrocarbon-bearing sands, in the North Sea, the Norwegian Sea, offshore Nigeria, offshore Gabon, Gulf of Mexico, and the Ouachita Mountains, are being reinterpreted by the present author as dominantly deposits of sandy debris flows and bottom-current reworking with only a minor percentage of true turbidites (i.e., deposits of turbidity currents with fluidal or Newtonian rheology in which sediment is suspended by fluid turbulence). This reinterpretation is based on detailed description of 21,000 ft (6402 m) of conventional cores and 1200 ft (365 m) of outcrop sections. The predominance of interpreted turbidites in these areas by other workers can be attributed to the following: (1) loose applications of turbidity-current concepts without regard for fluid rheology, flow state, and sediment-support mechanism that result in a category of 'turbidity currents' that includes debris flows and bottom currents; (2) field description of deep-water sands using the Bouma Sequence (an interpretive model) that invariably leads to a model-driven turbidite interpretation; (3) the prevailing turbidite mind set that subconsciously forces one to routinely interpret most deep-water sands as some kind of turbidites; (4) the use of our inability to interpret transport mechanism from the depositional record as an excuse for assuming deep-water sands as deposits of turbidity currents; (5) the flawed concept of high-density turbidity currents that allows room for interpreting debris-flow deposits as turbidites; (6) the flawed comparison of subaerial river currents (fluid-gravity flows dominated by bed-load transport) with subaqueous turbidity currents (sediment-gravity flows dominated by suspended load transport) that results in misinterpreting ungraded or parallel-stratified deep-sea deposits as turbidites; and (7) the attraction to use obsolete submarine-fan models with channels and lobes that require a turbidite interpretation. Although the turbidite paradigm is alive and well for now, the turbidites themselves are becoming an endangered facies!

Seismic stratigraphy and structure of the Chukchi Borderland: implications for the opening of the Canada Basin

NASA Astrophysics Data System (ADS)

Ilhan, I.; Coakley, B.

2015-12-01

Interpretation of seismic reflection data from the western Chukchi Borderland has illuminated the structure and stratigraphy of the area. Basement rotated fault blocks are offset by two border fault systems (BFS1 and BFS2) and by secondary faults, striking curvilinear in the NW-SE direction, dipping to the NE. The BFS1 dissects the Chukchi Plateau into two first-order rotated blocks bounding two major sedimentary depocentres, the North Chukchi Basin and the Chukchi Plateau Central Basin. The BFS2, which has a larger offset than BFS1, forms the western boundary of the Northwind Basin. Much of the stratigraphy is controlled by sediment supply. The basins were starved early in their history, resulting in a limited syn-rift section. Substantial sediment accumulation in the Borderland appears to post-date large scale progradation of the depostional shelf edge across the Chukchi Shelf. Basin infill stratigraphies are subdivided into pre-rift, syn-rift, early-, middle-, late post-rift, and glacio-marine sequences (SB1-SB5). SB1 shows truncation of the remnants of the pre-rift strata below and onlap of the syn-rift sequence(s) above; the SB2 marks the termination of the rifting stage and is bounded by bi-directional onlap surface of the early post-rift strata above; the base of SB3 is an onlap surface marks the arrival of the prograding shelf margin sequence(s); the SB4 shows evidence of erosion at the base of the prograding late post-rift sequence(s); and the SB5 is an downloap surface marking the first arrival of the glacio-marine sediments eroded from the Chukchi Shelf. Two ages of the major sequence boundaries, the SB3 and SB4, can be directly tied to Popcorn and Crackerjack Chukchi Shelf well data, and the older ones, the end of rifting and the top of the pre-rift, are inferred based on stratigraphic observations. The stratigraphic relationship suggests that the Chukchi Borderland stratigraphy can be correlated in part to the Chukchi Shelf stratigraphy. The first and second-order rotated fault blocks and depositional history suggest that the Chukchi Borderland has been coupled to the Chukchi Shelf at least since the extension of the Borderland. Therefore we infer only small horizontal offsets between the Chukchi Borderland and the Chukchi Shelf, which have largely a shared geologic history.

Shoreline deposits and diagenesis resulting from two Late Pleistocene highstands near +5 and +6 metres, Durban, South Africa

USGS Publications Warehouse

Cooper, J.A.G.; Flores, R.M.

1991-01-01

In exposures of Pleistocene rocks on the east coast of South Africa, eight sedimentary facies were distinguished on the basis of petrology, grain size, internal structures and field relationships. These are interpreted as deposits of surf zone, breaker zone, swash zone, backbeach, boulder beach and dune environments. Three phases of deposition and diagenesis are recognized. As a result of the stabilising effect of pre-existing coastal facies, the deposits from successive sea level stands are stacked vertically in a narrow coast-normal strip. Early cementation prevented erosion of the deposits during subsequent transgressions. Deposition of subsequent facies took place on an existing coastal dune (Facies 1). A terrace was cut into this dune at a sea level 4.5 to 5 m above present. At this sea level, clastic shoreline sediments were deposited which make up the main sedimentary sequence exposed (Facies 2-7). The steep swash zone, coarse grain size, and comparison with modern conditions in the study area indicate clastic deposition on a high-energy, wave-dominated, microtidal coastline. Vertical stacking of progressively shallower water facies indicates progradation associated with slightly regressive conditions, prior to stranding of the succession above sea level. During a subsequent transgression to 5.5 or 6 m above present sea level, a second terrace was cut across the existing facies, which by then were partly lithified. A boulder beach (Facies 8) deposited on this terrace is indicative of high wave energy and a rocky coastline, formed by existing cemented coastal facies. Comparison with dated deposits from other parts of the South African coast suggest a Late Pleistocene age for Facies 2-8. Deposition was terminated by subsequent regression and continuing low sea levels during the remainder of the Pleistocene. Cementation of the facies took place almost entirely by carbonate precipitation. The presence of isopachous fibrous cements suggests early cementation of Facies 1, 2, 3 and 4 under marine conditions, initially as aragonite which has since inverted to calcite. Facies 5, 6 and 7 are cemented only by equant calcite spar, evidence of cementation in the meteoric phreatic and vadose zones. Lowering of the water table during regression caused the remaining pore space in Facies 1, 2, 3 and 4 to be filled with equant calcite spar. Decementation in a 130 cm wide zone is attributed to water table shifts associated with the later transgression which deposited Facies 8. The vertical stacking of the two depositional sequences may be attributed to rapid cementation of Facies 2, 3, 4, 5, 6 and 7 under humid, subtropical conditions. This lithified sequence then acted as a focus for deposition of coarse-grained shoreline facies (Facies 8) during the subsequent transgression. ?? 1991.

Sequence Stratigraphy of the Dakota Sandstone, Eastern San Juan Basin, New Mexico, and its Relationship to Reservoir Compartmentalization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varney, Peter J.

2002-04-23

This research established the Dakota-outcrop sequence stratigraphy in part of the eastern San Juan Basin, New Mexico, and relates reservoir quality lithologies in depositional sequences to structure and reservoir compartmentalization in the South Lindrith Field area. The result was a predictive tool that will help guide further exploration and development.

46 CFR 201.111 - Contents of order.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 8 2012-10-01 2012-10-01 false Contents of order. 201.111 Section 201.111 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION POLICY, PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Discovery and Depositions (Rule 11) § 201.111 Contents of order. The order issued authorizing the taking of a deposition will state the...

Transcriptional profiling reveals the expression of novel genes in response to various stimuli in the human dermatophyte Trichophyton rubrum

PubMed Central

2010-01-01

Background Cutaneous mycoses are common human infections among healthy and immunocompromised hosts, and the anthropophilic fungus Trichophyton rubrum is the most prevalent microorganism isolated from such clinical cases worldwide. The aim of this study was to determine the transcriptional profile of T. rubrum exposed to various stimuli in order to obtain insights into the responses of this pathogen to different environmental challenges. Therefore, we generated an expressed sequence tag (EST) collection by constructing one cDNA library and nine suppression subtractive hybridization libraries. Results The 1388 unigenes identified in this study were functionally classified based on the Munich Information Center for Protein Sequences (MIPS) categories. The identified proteins were involved in transcriptional regulation, cellular defense and stress, protein degradation, signaling, transport, and secretion, among other functions. Analysis of these unigenes revealed 575 T. rubrum sequences that had not been previously deposited in public databases. Conclusion In this study, we identified novel T. rubrum genes that will be useful for ORF prediction in genome sequencing and facilitating functional genome analysis. Annotation of these expressed genes revealed metabolic adaptations of T. rubrum to carbon sources, ambient pH shifts, and various antifungal drugs used in medical practice. Furthermore, challenging T. rubrum with cytotoxic drugs and ambient pH shifts extended our understanding of the molecular events possibly involved in the infectious process and resistance to antifungal drugs. PMID:20144196

Multi-proxies Approach of Climatic Records In Terrestrial Mollusks Shells

NASA Astrophysics Data System (ADS)

Labonne, M.; Rousseau, D. D.; Ben Othman, D.; Luck, J. M.; Metref, S.

Fossil land snails shells constitute a valuable source of information for the study of Quaternary deposits as they are commonly preserved in many regions and notably in loess sequences. The use of stable isotope composition of the carbonate in the shells was previously applied to reconstruct past climate or environnements but the technic was not widely exploited and compared with other proxies from the same sequence. In this study, we have analysed stables isotopes, trace elements and Sr isotopes from both shells of land snails Vertigo modesta and the sediment from the Eustis upper Pleistocene loess sequence (Nebraska, USA). This serie developed during the last glaciation and records the last deglaciation between 18,000 and 12,000 B.P. years. We compare the paleoclimatic information obtained by different proxies, such as mag- netic susceptibility, temperature and moisture estimated by land snails assemblage with geochemical data measured on land snails shells in order to validate the climatic information obtained with this proxy. Our study demonstrates that shell carbonate reflects environmental conditions estimated by other proxies. Carbon and oxygen iso- topes show cyclic variations (millenial cycles) along the profile which correlate with stratigraphic units and could be link with the retreat of the Laurentide ice sheet. Trace element and Sr isotopes in the shells indicate various origins for the eolian dusts in the two main loess units along the sequence.

Directions for Space-Based Low-Frequency Radio Astronomy 2. Telescopes

NASA Astrophysics Data System (ADS)

Basart, J. P.; Burns, J. O.; Dennison, B. K.; Weiler, K. W.; Kassim, N. E.; Castillo, S. P.; McCune, B. M.

Astronomical studies of celestial sources at low radio frequencies (0.3 to 30 MHz) lag far behind the investigations of celestial sources at high radio frequencies. In a companion paper [Basart et al., this issue] we discussed the need for low-frequency investigations, and in this paper we discuss the telescopes required to make the observations. Radio telescopes for use in the low-frequency range can be built principally from ``off-the-shelf'' components. For relatively little cost for a space mission, great strides can be made in deploying arrays of antennas and receivers in space that would produce data contributing significantly to our understanding of galaxies and galactic nebulae. In this paper we discuss an evolutionary sequence of telescopes, antenna systems, receivers, and (u,v) plane coverage. The telescopes are space-based because of the disruptive aspects of the Earth's ionosphere on low-frequency celestial signals traveling to the Earth's surface. Orbiting antennas consisting of array elements deposited on a Kevlar balloon have strong advantages of nearly identical multiple beams over 4π steradians and few mechanical aspects in deployment and operation. The relatively narrow beam width of these antennas can significantly help reduce the ``confusion'' problem. The evolutionary sequence of telescopes starts with an Earth-orbiting spectrometer to measure the low-frequency radio environment in space, proceeds to a two-element interferometer, then to an orbiting array, and ends with a telescope on the lunar farside. The sequence is in the order of increasing capability which is also the order of increasing complexity and cost. All the missions can be accomplished with current technology.

Trace fossils, storm beds, and depositional sequences in a clastic shelf setting, Upper Cretaceous of Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frey, R.W.

In Coal Creek Canyon, Utah the Spring Canyon Member of the Blackhawk Formation is divisible into four regressive hemicycles of deposition each representing the downdip part of a nearshore-to-offshore sequence punctuated locally by hummocky cross-stratification. Bedding units span middle shoreface to lower offshore shelf lithofacies, the latter corresponding to a transgressive intertongue of the Mancos Shale. Trace fossil assemblage include 21 ichnospecies distributed among 17 ichnogenera: Ancorichnus, Aulichnites, Chondrites, Cylindrichnus, Ophiomorpha, Palaeophycus, Phoebichnus, Planolites, Rosselia, Schaubcylindrichnus, Scolicia, Skolithos, Taenidium, Teichichnus, Terebellina, Thalassinoides, and Uchirites. Distal deposits are typified by bioturbate textures; Cylindrichnus concentricus, Palaeophycus heberti, and Rosselia socialis otherwise aremore » prevalent throughout the lithofacies suite. Ophiomorpha irregulaire and Schaubcylindrichnus are most common in middle shoreface beds and Chondrites sp. in upper offshore beds; O. nodosa and O. annulata also are common in this part of the sequence. Planolites-type feeding burrows must have been predominant in many depositional settings but now remain inconspicuous and poorly preserved. Despite gradients in environmental distributions of trace fossils, all resident ichnofaunas are referable to the archetypical Cruziana ichnocoenose. Ichnofaunas in hummocky beds mainly represent either an archetypical Skolithos ichnocoenose or mixed Skolithos-Cruziana ichnocoenose. These post-storm ichnocoenoses correspond primarily to a sere of opportunistic pioneers and secondarily to ensuing seres of resilient resident populations. Differences in ichnofacies also are related to differences in post-storm rates of deposition: the slower the rate of sediment accumulation, the greater the degree of overprinting by burrows from subsequent seres or equilibrium communities.« less

Numeric stratigraphic modeling: Testing sequence Numeric stratigraphic modeling: Testing sequence stratigraphic concepts using high resolution geologic examples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armentrout, J.M.; Smith-Rouch, L.S.; Bowman, S.A.

1996-08-01

Numeric simulations based on integrated data sets enhance our understanding of depositional geometry and facilitate quantification of depositional processes. Numeric values tested against well-constrained geologic data sets can then be used in iterations testing each variable, and in predicting lithofacies distributions under various depositional scenarios using the principles of sequence stratigraphic analysis. The stratigraphic modeling software provides a broad spectrum of techniques for modeling and testing elements of the petroleum system. Using well-constrained geologic examples, variations in depositional geometry and lithofacies distributions between different tectonic settings (passive vs. active margin) and climate regimes (hothouse vs. icehouse) can provide insight tomore » potential source rock and reservoir rock distribution, maturation timing, migration pathways, and trap formation. Two data sets are used to illustrate such variations: both include a seismic reflection profile calibrated by multiple wells. The first is a Pennsylvanian mixed carbonate-siliciclastic system in the Paradox basin, and the second a Pliocene-Pleistocene siliciclastic system in the Gulf of Mexico. Numeric simulations result in geometry and facies distributions consistent with those interpreted using the integrated stratigraphic analysis of the calibrated seismic profiles. An exception occurs in the Gulf of Mexico study where the simulated sediment thickness from 3.8 to 1.6 Ma within an upper slope minibasin was less than that mapped using a regional seismic grid. Regional depositional patterns demonstrate that this extra thickness was probably sourced from out of the plane of the modeled transect, illustrating the necessity for three-dimensional constraints on two-dimensional modeling.« less

Stratigraphy of a proposed wind farm site southeast of Block Island: Utilization of borehole samples, downhole logging, and seismic profiles

NASA Astrophysics Data System (ADS)

Sheldon, Dane P. H.

Seismic stratigraphy, sedimentology, lithostratigraphy, downhole geophysical logging, mineralogy, and palynology were used to study and interpret the upper 70 meters of the inner continental shelf sediments within a proposed wind farm site located approximately two to three nautical miles to the southeast of Block Island, Rhode Island. Core samples and downhole logging collected from borings drilled for geotechnical purposes at proposed wind turbine sites along with seismic surveys in the surrounding area provide the data for this study. Cretaceous coastal plain sediments that consist of non-marine to marine sand, silt, and clay are found overlying bedrock at a contact depth beyond the sampling depth of this study. The upper Cretaceous sediments sampled in borings are correlated with the Magothy/Matawan formations described regionally from New Jersey to Nantucket. An unconformity formed through sub-aerial, fluvial, marine, and glacial erosion marks the upper strata of the Cretaceous sediments separating them from the overlying deposits. The majority of Quaternary deposits overlying the unconformity represent the advance, pulsing, and retreat of the Laurentide ice sheet that reached its southern terminus in the area of Block Island approximately 25,000 to 21,000 years before present. The sequence consists of a basal glacial till overlain by sediments deposited by meltwater environments ranging from deltaic to proglacial lakefloor. A late Pleistocene to early Holocene unconformity marks the top of the glacial sequence and was formed after glacial retreat through fluvial and subaerial erosion/deposition. Overlying the glacial sequence are sediments deposited during the late Pleistocene and Holocene consisting of interbedded gravel, sand, silt, and clay. Sampling of these sediments was limited and surficial reflectors in seismic profiles were masked due to a hard bottom return. However, two depositional periods are interpreted as representing fluvial and estuarine/marine environments respectively. One sample recovered at five meters contained shell fragments within a gray fine to coarse sand possibly representing a shallow estuarine to marine environment. A coarse near surface deposit described but not recovered in all borings may represent a transgressive unconformity and resulting lag deposit however due to lack of sampling and seismic resolution in the upper 5 meters, the nature of this deposit is merely speculation. In areas where depth to the glacial surface increased, sediments ranging from sand to fine-grained silt and clay were encountered in borings. In summary, the upper 70 meters of the inner continental shelf section within the study site consists of unconsolidated sediments spanning three major depositional periods. Sediments derived from glacial activity represent the bulk of samples collected. The glacial sequences represent various depositional environments, although most samples are interpreted to be the product of glacial meltwater deposition with distribution determined by source as well as highs and lows present in the antecedent topography. Finely laminated (varved) sediment to the south of Block Island indicates the presence of proglacial lakes in the area during the time of glacial retreat. Overlying sediments represent environments ranging from fluvial to marine.

Chronostratigraphic and depositional sequences of the Fort Union formation (Paleocene), Williston Basin, North Dakota, South Dakota, and Montana

USGS Publications Warehouse

Warwick, Peter D.; Flores, Romeo M.; Nichols, Douglas J.; Murphy, Edward C.; Pashin, Jack C.; Gastaldo, Robert A.

2004-01-01

The Fort Union Formation in the Williston Basin of North Dakota, South Dakota, and Montana comprises chronostratigraphic and depositional sequences of Paleocene age. Individual chronostratigraphic sequences are defined by palynostratigraphic (pollen and spore) biozones and radiometric (40Ar/39Ar) ages obtained from tonsteins or volcanic ash layers. Analyses of depositional sequences are based on lithofacies constrained by the radiometric ages and biozones.The lower Paleocene (biozones P1-P3) contains three marine parasequences (landward stepping) in southwestern North Dakota that sequentially onlapped westward between 65 and 61 Ma (lower Ludlow and Cannonball Members). Maximum flooding (transgressive systems tract) occurred during an approximate 1-m.y. interval from 65 to 64 Ma, which regionally is correlated biostratigraphically to a tidally influenced, distributary-shoreface, and fluvial-channel complex in the Cave Hills, northwestern South Dakota, and to channel-dominated fluvial (low-stand incised paleovalley systems) and tidally influenced, flood-plain-deltaic transition facies in the Ekalaka area of southeastern Montana.The progradational parasequences in the Cannonball Member consist of shore-face sandstone beds (with ravinement lag deposits) deposited by strand-plain barrier systems. Landward of the barrier systems, tidal-estuarine and mire deposits included thick but laterally discontinuous peat accumulations (e.g., Beta and Yule coal beds in the Ludlow Member, southwestern North Dakota). However, landward of the coastal deposits, the laterally equivalent T-Cross-Big Dirty coal zone (dated 64.78 Ma) in southeastern Montana formed as thick, laterally extensive peat accumulations in mires in a fluvial setting. In the flood-plain-deltaic, tidal transition zone near Ekalaka, Montana, the Ludlow Member consists of flood-plain facies, discontinuous coal beds, and rooted and burrowed horizons that contain the marine or brackish trace fossil Skolithos. The flood-plain-deltaic tidal transition zone facies are incised by a massive, agglomerated channel sandstone complex (paleovalley fill) that is exposed along the modern Snow Creek drainage south of Mill Iron, Montana. The flood-plain-tidal transition zone was reworked during the maximum sea level highstand during the early Paleocene. This event was followed by a fall of sea level and deposition of the paleovalley fill.Sea level fall during the mid-Paleocene (biozones P3 and P4) produced a regressive shallow-marine and lower deltaic tidal system (seaward stepping) that deposited strata that thin toward the east. These strata are overlain by a widespread paleosol (Rhame bed) and, in turn, a lignite-bearing fluvial facies (Tongue River Member) containing the laterally persistent Harmon-Hanson coal zone (61.23 Ma). Upper Paleocene biozone P5 is represented by fluvial, coal-bearing strata that contain several economically minable coal beds (HT Butte, Hagel, and Beulah-Zap zones, Sentinel Butte Member).The Fort Union Formation of the Williston Basin contains significant coal resources. These coal deposits are now being explored for their potential coal-bed gas resources. A better understanding of the depositional setting for these deposits can lead to improved exploration and exploitation practices and a better understanding of regional paleogeography and paleoclimate during the Paleocene.

Solidification Sequence of Spray-Formed Steels

NASA Astrophysics Data System (ADS)

Zepon, Guilherme; Ellendt, Nils; Uhlenwinkel, Volker; Bolfarini, Claudemiro

2016-02-01

Solidification in spray-forming is still an open discussion in the atomization and deposition area. This paper proposes a solidification model based on the equilibrium solidification path of alloys. The main assumptions of the model are that the deposition zone temperature must be above the alloy's solidus temperature and that the equilibrium liquid fraction at this temperature is reached, which involves partial remelting and/or redissolution of completely solidified droplets. When the deposition zone is cooled, solidification of the remaining liquid takes place under near equilibrium conditions. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to analyze the microstructures of two different spray-formed steel grades: (1) boron modified supermartensitic stainless steel (SMSS) and (2) D2 tool steel. The microstructures were analyzed to determine the sequence of phase formation during solidification. In both cases, the solidification model proposed was validated.

Quartz crystal fabrication facility

NASA Astrophysics Data System (ADS)

Ney, R. J.

1980-05-01

The report describes the design and operation of a five chamber, interconnected vacuum system, which is capable of cleaning, plating, and sealing precision quartz crystal units in ceramic flatpack enclosures continuously in a high vacuum environment. The production rate design goal was 200 units per eight hour day. A unique nozzle beam gold deposition source was developed to operate for extended periods of time without reloading. The source puts out a narrow beam of gold typically in the order of 2 1/2 deg included cone angle. Maximum deposition rates are in the order of 400 a/min at 5.5 in. 'throw' distance used. Entrance and exit air lock chambers expedite the material throughput, so that the processing chambers are at high vacuum for extended periods of time. A stainless steel conveyor belt, in conjunction with three vacuum manipulators, transport the resonator components to the various work stations. Individual chambers are normally separated from each other by gate valves. The crystal resonators, mounted in flatpack frames but unplated, are loaded into transport trays in a lid-frame-lid sequency for insertion into the system and exit as completed crystal units. The system utilizes molybdenum coated ball bearings at essentially all friction surfaces. The gold sources and plating mask heads are equipped with elevators and gate valves, so that they can be removed from the system for maintenance without exposing the chambers to atmosphere.

Depositional evolution of permo-triassic karoo basins in Tanzania with reference to their economic potential

NASA Astrophysics Data System (ADS)

Kreuser, T.; Wopfner, H.; Kaaya, C. Z.; Markwort, S.; Semkiwa, P. M.; Aslandis, P.

The Karoo basins of Tanzania contain in excess of 3000 m of sediments which were preserved in several NNE-NE striking half grabens or other structural basin conditions. They are all intracratonic basins, most of which filled with terrestrial sediments. In some basins situated nearer the coastal region short marine incursions occurred in the Late Permian. The Ruhuhu Rasin in SW Tanzania provides a typical depositional sequence of a Karoo basin in eastern Africa. Sedimentation commenced with glacigene deposits. These are of Late Carboniferous to Early Permian age and may be equated with other glacial successions in Africa and elsewhere in Gondwana. The glacigene beds are overlain by fluvial-deltaic coal-bearing deposits succeeded by arkoses and continental red beds. A transitionary formation of carbonaceous shales with impure coals gradually develops into thick lacustrine series which are topped by Late Permian bone bearing beds. The Triassic is characterized by a very thick fluvio-deltaic succession of siliciclastics resting with regional unconformity on the Permian. This Early Triassic sequence exhibits well-developed repetitive depositional cycles. Current azimuth measurements indicate fluctuating flow regimes in the Early Permian but relative stable source areas to the west of the basin later on. The depositional evolution of the Ruhuhu Basin is controlled by both tectonic and climatic factors. During basin evolution important energy resources were deposited such as considerable reserves of coal and source rocks of moderate potential for hydrocarbon generation. Uranium enrichment is observed in the Triassic arenaceous series where diagenetic alterations and subsequent cementation processes led to the formation of laumontite. Post Karoo dykes and plugs had only local effect on thermal evolution of potential source rocks. Enrichments of elements, i.e., Nb, Zr, Rb, Cr, and V present additional exploration targets. A comparison with the Karoo basins of the coastal region indicates possible lithological correlation by the application of sequence stratigraphy. No early Permian deposits are exposed in the coastal Karoo basins but their existence within the deeper parts of these basins cannot be ruled out. There, composition of organic matter analysed so far suggests subsidence and heat exposure exceeding post maturity stage.

Tectonic and climatic controls on continental depositional facies in the Karoo Basin of northern Natal, South Africa

NASA Astrophysics Data System (ADS)

Turner, Brian R.

1986-02-01

The eastern Karoo Basin, South Africa, contains a thick sequence of terrigenous clastic sediments comprising a meanderbelt facies, braided channel facies divided into coarse and fine subfacies, fluviolacustrine facies and aeolian facies. Depositional trends and changes in fluvial style reflect a progressive increase in aridity of the climate under stable tectonic conditions, interrupted by two phases of source area tectonism and the development of fine and coarse clastic wedges of the braided channel subfacies; the latter signifying a short interlude of cool, wet conditions. The fine braided channel subfacies occurs in the upper part of the meanderbelt facies, which was deposited by ephemeral, meandering mixed-load streams of variable discharge and sinuosity, under dry, semi-arid climatic conditions. These deposited complex, internally discordant channel sands and well-developed levee deposits. Following deposition of the coarse braided channel subfacies semi-arid conditions returned and fluvial deposition was dominated by ephemeral, straight to slightly sinuous mixed load streams characterised by simple channel sand bodies. As the aridity of the climate increased, the streams became more localised and carried an increasing proportion of fines. Interbedded with and overlying the fluvial deposits is a mudstone-dominated lacustrine sequence grading up into aeolian sands suggesting a playa lake-type situation. The general absence of evaporites from these sediments is attributed to the fresh nature of the lake waters, as evidenced by the freshwater aquatic organisms and clay-mineral suite, the lack of adequate inflow for solute accumulation and the removal of dust impregnated by salts from the surface of the dry lake bed during the dry season by superheated, upward-spiralling columns of air. Broadly similar environments to the fluvio-lacustrine and aeolian facies sequence are to be found in the Lake Eyre Basin of central Australia and the Okavango "delta" of northern Botswana. The Okavango "delta" model has an important bearing on patterns of fluvial sedimentation in arid regions since it shows many characteristics of temperate, well-vegetated anastomosed fluvial systems despite its location in the Kalahari Desert.

Deposition model of a Miocene barred wave- and storm-dominated shoreface and shelf, southeastern Malay basin, offshore west Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramli, N.

1986-01-01

The J sandstone is an important hydrocarbon-bearing reservoir in the southeastern part of the Malay basin. The lower and upper members of the J sandstone are composed of shoreface and offshore sediments. The shoreface sequence contains depositional structures characteristic of a barred wave- and storm-dominated shoreface. Each shoreface sequence is laterally associated with a series of stacked offshore bars. Offshore bars can be subdivided into proximal and distal types. Two types of proximal offshore bars have been identified: (1) proximal bars formed largely above fair-weather wave base (inner proximal bars), and (2) proximal bars formed below fair-weather wave base (outermore » proximal bars). The inner proximal bars are closely associated with the shoreface sequence and are similar to the middle and lower shoreface. The presence of poorly sorted, polymodal, very fine to very coarse-grained sandstone beneath well-sorted crestal sandstones of inner proximal bars suggests that these offshore bars may have been deposited rapidly by storms. The crests of the inner proximal offshore bars were subsequently reworked by fair-weather processes, and the crests of the outer proximal and distal offshore bars were reworked by waning storm currents and oscillatory waves. Thick marine shales overlying offshore bars contain isolated sheet sandstones. Each sheet sandstone exhibits features that may be characteristic of distal storm shelf deposits. 15 figures, 2 tables.« less

Miocene and Pliocene lacustrine and fluvial sequences, Upper Ramparts and Canyon village, Porcupine river, east-central Alaska

USGS Publications Warehouse

Fouch, T.D.; Carter, L.D.; Kunk, Michael J.; Smith, C.A.S.; White, J.M.

1994-01-01

Cenozoic strata exposed along the Porcupine River between the Upper Ramparts and Canyon Village, Alaska, can be divided into five unconformity-bounded units (sequences) which are: lower and middle Miocene unit A, the white sandy fluvial sequence with peat beds; middle Miocene unit B, the basalt sequence-part B1 is basalt, and part B2 is organic-rich sedimentary beds; upper Miocene unit C, mudrock-dominated lake sequence; late Miocene or Pliocene to Pleistocene unit D, terrace gravels, detrital organic matter and associated sediments, and Holocene unit E, mixed sand and gravel-rich sediment and other sedimentary material including peat and eolian silt. The sequence (unit A) of lower and middle Miocene fluvial deposits formed in streams and on flood plains, just before the inception of local volanism. Fossil pollen from unit A suggests conifer-dominated regional forests and cool temperate climates. Peat beds and lake deposits from unit B contain pollen that indicates a warmer temperate climate coinciding with the middle Miocene thermal maximum. The lake deposits (unit C) downstream from the basalts accumulated in a small basin which resulted from a hydrologic system that was dammed in the late Miocene but breached soon thereafter. The lower part of the terrace gravels (unit D) expresses breaching of the dammed hydrologic system (of unit C). The Porcupine River became a major tributary of the Yukon River in late Pleistocene time when Laurentide ice blocked drainage from the Yukon interior basins causing meltwater to spill over the low divide separating it from the Porcupine River drainage initiating erosion and capture of the Yukon interior basins. ?? 1994.

Petroleum system elements within the Late Cretaceous and Early Paleogene sediments of Nigeria's inland basins: An integrated sequence stratigraphic approach

NASA Astrophysics Data System (ADS)

Dim, Chidozie Izuchukwu Princeton; Onuoha, K. Mosto; Okeugo, Chukwudike Gabriel; Ozumba, Bertram Maduka

2017-06-01

Sequence stratigraphic studies have been carried out using subsurface well and 2D seismic data in the Late Cretaceous and Early Paleogene sediments of Anambra and proximal onshore section of Niger Delta Basin in the Southeastern Nigeria. The aim was to establish the stratigraphic framework for better understanding of the reservoir, source and seal rock presence and distribution in the basin. Thirteen stratigraphic bounding surfaces (consisting of six maximum flooding surfaces - MFSs and seven sequence boundaries - SBs) were recognized and calibrated using a newly modified chronostratigraphic chart. Stratigraphic surfaces were matched with corresponding foraminiferal and palynological biozones, aiding correlation across wells in this study. Well log sequence stratigraphic correlation reveals that stratal packages within the basin are segmented into six depositional sequences occurring from Late Cretaceous to Early Paleogene age. Generated gross depositional environment maps at various MFSs show that sediment packages deposited within shelfal to deep marine settings, reflect continuous rise and fall of sea levels within a regressive cycle. Each of these sequences consist of three system tracts (lowstand system tract - LST, transgressive system tract - TST and highstand system tract - HST) that are associated with mainly progradational and retrogradational sediment stacking patterns. Well correlation reveals that the sand and shale units of the LSTs, HSTs and TSTs, that constitute the reservoir and source/seal packages respectively are laterally continuous and thicken basinwards, due to structural influences. Result from interpretation of seismic section reveals the presence of hanging wall, footwall, horst block and collapsed crest structures. These structural features generally aid migration and offer entrapment mechanism for hydrocarbon accumulation. The combination of these reservoirs, sources, seals and trap elements form a good petroleum system that is viable for hydrocarbon exploration and development.

Archaeal Distribution in Moonmilk Deposits from Alpine Caves and Their Ecophysiological Potential.

PubMed

Reitschuler, Christoph; Spötl, Christoph; Hofmann, Katrin; Wagner, Andreas O; Illmer, Paul

2016-04-01

(Alpine) caves are, in general, windows into the Earth's subsurface. Frequently occurring structures in caves such as moonmilk (secondary calcite deposits) offer the opportunity to study intraterrestrial microbial communities, adapted to oligotrophic and cold conditions. This is an important research field regarding the dimensions of subsurface systems and cold regions on Earth. On a methodological level, moonmilk deposits from 11 caves in the Austrian Alps were collected aseptically and investigated using a molecular (qPCR and DGGE sequencing-based) methodology in order to study the occurrence, abundance, and diversity of the prevailing native Archaea community. Furthermore, these Archaea were enriched in complex media and studied regarding their physiology, with a media selection targeting different physiological requirements, e.g. methanogenesis and ammonia oxidation. The investigation of the environmental samples showed that all moonmilk deposits were characterized by the presence of the same few habitat-specific archaeal species, showing high abundances and constituting about 50 % of the total microbial communities. The largest fraction of these Archaea was ammonia-oxidizing Thaumarchaeota, while another abundant group was very distantly related to extremophilic Euryarchaeota (Moonmilk Archaea). The archaeal community showed a depth- and oxygen-dependent stratification. Archaea were much more abundant (around 80 %), compared to bacteria, in the actively forming surface part of moonmilk deposits, decreasing to about 5 % down to the bedrock. Via extensive cultivation efforts, it was possible to enrich the enigmatic Moonmilk Archaea and also AOA significantly above the level of bacteria. The most expedient prerequisites for cultivating Moonmilk Archaea were a cold temperature, oligotrophic conditions, short incubation times, a moonmilk surface inoculum, the application of erythromycin, and anaerobic (microaerophilic) conditions. On a physiological level, it seems that methanogenesis is of marginal importance, while ammonia oxidation and a still undiscovered metabolic pathway are vital elements in the (archaeal) moonmilk biome.

Physical and chemical controls on ore shoots - insights from 3D modeling of an orogenic gold deposit

NASA Astrophysics Data System (ADS)

Vollgger, S. A.; Tomkins, A. G.; Micklethwaite, S.; Cruden, A. R.; Wilson, C. J. L.

2016-12-01

Many ore deposits have irregular grade distributions with localized elongate and well-mineralized rock volumes commonly referred to as ore shoots. The chemical and physical processes that control ore shoot formation are rarely understood, although transient episodes of elevated permeability are thought to be important within the brittle and brittle-ductile crust, due to faulting and fracturing associated with earthquake-aftershock sequences or earthquake swarms. We present data from an orogenic gold deposit in Australia where the bulk of the gold is contained in abundant fine arsenopyrite crystals associated with a fault-vein network within tight upright folds. The deposit-scale fault network is connected to a deeper network of thrust faults (tens of kilometers long). Using 3D implicit modeling of geochemical data, based on radial basis functions, gold grades and gold-arsenic element ratios were interpolated and related to major faults, vein networks and late intrusions. Additionally, downhole bedding measurements were used to model first order (mine-scale) fold structures. The results show that ore shoot plunges are not parallel with mine-scale or regional fold plunges, and that bedding parallel faults related to flexural slip folding play a pivotal role on ore shoot attitudes. 3D fault slip and dilation tendency analysis indicate that fault reactivation and formation of linking faults are associated with large volumes of high-grade ore. We suggest slip events on the large-scale thrust network allowed mineralizing fluids to rapidly migrate over large distances and become supersaturated in elements such as gold, promoting widespread precipitation and high nucleation densities of arsenopyrite upon fluid-rock interaction at trap sites within the deposit.

The first polluted river? Repeated copper contamination of fluvial sediments associated with Late Neolithic human activity in southern Jordan.

PubMed

Grattan, J P; Adams, R B; Friedman, H; Gilbertson, D D; Haylock, K I; Hunt, C O; Kent, M

2016-12-15

The roots of pyrometallurgy are obscure. This paper explores one possible precursor, in the Faynan Orefield in southern Jordan. There, at approximately 7000cal. BP, banks of a near-perennial meandering stream (today represented by complex overbank wetland and anthropogenic deposits) were contaminated repeatedly by copper emitted by human activities. Variations in the distribution of copper in this sequence are not readily explained in other ways, although the precise mechanism of contamination remains unclear. The degree of copper enhancement was up to an order of magnitude greater than that measured in Pleistocene fluvial and paludal sediments, in contemporary or slightly older Holocene stream and pond deposits, and in the adjacent modern wadi braidplain. Lead is less enhanced, more variable, and appears to have been less influenced by contemporaneous human activities at this location. Pyrometallurgy in this region may have appeared as a byproduct of the activity practised on the stream-bank in the Wadi Faynan ~7000years ago. Copyright © 2016. Published by Elsevier B.V.

Non cardiopatic and cardiopatic beta thalassemic patients: quantitative and qualitative cardiac iron deposition evaluation with MRI.

PubMed

Macarini, L; Marini, S; Pietrapertosa, A; Scardapane, A; Ettorre, G C

2005-01-01

Cardiomyopathy is one of the major complications of b thalassaemia major as a result of transfusional iron overload. The aim of our study is to evaluate with MR if there is any difference of iron deposition signal intensity (SI) or distribution between non-cardiopathic and cardiopathic thalassaemic patients in order to establish if there is a relationship between cardiopathy and iron deposition. We studied 20 patients affected by b thalassaemia major, of whom 10 cardiopathic and 10 non-cardiopathic, and 10 healthy volunteers as control group. Serum ferritin and left ventricular ejection fraction were calculated in thalassaemic patients. All patients were examined using a 1.5 MR unit with ECG-gated GE cine-MR T2*-weighted, SE T1-weighted and GE T2*-weighted sequences. In all cases, using an adequate ROI, the myocardial and skeletal muscle signal intensity (SI), the myocardial/skeletal muscle signal intensity ratio (SIR) and the SI average of the myocardium and skeletal muscle were calculated for every study group. The qualitative evaluation of iron deposition distribution was independently performed by three radiologists who analyzed the extension, the site and the morphology of iron deposition on the MR images and reported their observations on the basis of a four-level rating scale: 0 (absent), 1 (limited), 2 (partial), 3 (widespread deposition). The result of quantitative and qualitative evaluations were analysed with statistical tests. Cardiac iron deposition was found in 8/10 non-cardiopathic thalassaemic patients and in all cardiopathic thalassaemic patients. We noticed a significant SI difference (p>0.05) between the healthy volunteer control group and the thalassaemic patients with iron deposition, but no significant SI difference in iron deposition between non-cardiopathic and cardiopathic thalassaemic patients in the areas evaluated. The qualitative evaluation revealed a different distribution of iron deposition between the two thalassaemic groups, with more widespread distribution in cardiopathic patients. We found cardiac iron deposition also in non-cardiopathic b thalassaemic patients and a qualitative difference in cardiac iron distribution between non-cardiopathic and cardiopathic patients. The qualitative evaluation of cardiac iron deposition was useful for an easier classification of the disease, bypassing the SI quantitative value which is affected by the extremely uneven distribution of iron deposition and by the sampling technique used. MR evaluation of non-cardiopathic thalassaemic patients may be useful to evaluate early iron deposition and to establish the most suitable chelation therapy.

Stratigraphic architecture and gamma ray logs of deeper ramp carbonates (Upper Jurassic, SW Germany)

NASA Astrophysics Data System (ADS)

Pawellek, T.; Aigner, T.

2003-07-01

The objective of this paper is to contribute to the development of sequence stratigraphic models for extensive epicontinental carbonate systems deposited over cratonic areas. Epicontinental carbonates of the SW German Upper Jurassic were analysed in terms of microfacies, sedimentology and sequence stratigraphy based on 2.5 km of core, 70 borehole gamma ray logs and 24 quarries. Facies analysis revealed six major facies belts across the deeper parts of the carbonate ramp, situated generally below fair-weather wave base, and mostly below average storm wave base but in the reach of occasional storm events. Observed stratigraphic patterns differ in some aspects from widely published sequence stratigraphic models: Elementary sedimentary cycles are mostly more or less symmetrical and are, thus, referred to as "genetic sequences" or "genetic units" [AAAPG Bull. 55 (1971) 1137; Frazier, D.E., 1974. Depositional episodes: their relationship to the Quaternary stratigraphic framework in the northwestern portion of the Gulf Basin. University of Texas, Austin, Bureau of Economic Geology Geologicalo Circular 71-1; AAPG Bull. 73 (1989) 125; Galloway, W.E., Hobday, D.K., 1996. Terrigenous Clastic Depositional Systems. 489 pp., Springer; Cross, T.A., Baker, M.R., Chapin, M.S., Clark, M.S., Gardner, M.H., Hanson, M.S., Lessenger, M.A., Little, L.D., McDonough, K.J., Sonnenfeld, M.D., Valasek, D.W., Williams, M.R., Witter, D.N., 1993. Applications of high-resolution sequence stratigraphy to reservoir analysis. Edition Technip 1993, 11-33; Bull. Cent. Rech. Explor. Prod. Elf-Aquitaine 16 (1992) 357; Homewood, P., Mauriaud, P., Lafont, F., 2000. Best practices in sequence stratigraphy. Elf EP Mem. 25, 81 pp.; Homewood, P., Eberli, G.P., 2000. Genetic stratigraphy on the exploration and production scales. Elf EP Mem. 24, 290 pp.], in contrast to the asymmetrical, shallowing-upward "parasequences" of the EXXON approach. Neither sequence boundaries nor maximum flooding surfaces could be clearly delineated. Cycle boundaries are generally not represented by sharp stratal surfaces but are always transitional and, thus, referred to as "turnarounds" [Nor. Pet. Soc. Spec. Publ. 8 (1998) 171]. Several types of genetic sequences were delineated. Both major types of facies and sequences show characteristic gamma ray log signatures. Based on the cycle stacking and the gamma ray patterns, a hierarchy of sequences was recognized, probably driven in part by 100,000- and 400,000-year Milankovitch signals. The cyclicity allowed regional correlations across various depositional environments such as sponge-microbial bioherms and coeval basins. The basin-wide correlation revealed evidence for a subtle clinoform-type stratigraphic architecture along very gentle slopes, rather than a so far assumed simple "layer cake" pattern.

Formation and tectonic evolution of the Pattani Basin, Gulf of Thailand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bustin, R.M.; Chonchawalit, A.

The stratigraphic and structural evolution of the Pattani Basin, the most prolific petroleum basin in Thailand, reflects the extensional tectonic regime of continental Southeast Asia. E-W extension resulting from the northward collision of India with Eurasia since the Early Tertiary resulted in the formation of a series of N-S-trending sedimentary basins, which include the Pattani Basin. The sedimentary succession in the Pattani Basin is divisible into synrift and postrift sequences. Deposition of the synrift sequence accompanied rifting and extension, with episodic block faulting and rapid subsidence. The synrift sequence comprises three stratigraphic units: (1) Upper Eocene to Lower Olikgocene alluvial-fan,more » braided-river, and floodplain deposits; (2) Upper oligocene to Lowe Miocene floodplain and channel deposits; and (3) a Lower Miocene regressive package consisting of marine to nonmarine sediments. Post-rift succession comprises: (1) a Lower to Middle Miocene regressive package of shallow marine sediments through floodplain and channel deposits; (2) an upper Lower Miocene transgressive sequence; and (3) and Upper Miocene to Pleistocene transgressive succession. The post-rift phase is characterized by slower subsidence and decreased sediment influx. The present-day shallow-marine condition in the Gulf of Thailand is the continuation of this latest transgressive phase. The subsidence and thermal history of the Pattani Basin is consistent with a nonuniform lithospheric-stretching model. The amount of extension as well as surface heat flow generally increases from the margin to the basin center. The crustal stretching factor ({beta}) varies form 1.3 at the basin margin to 2.8 in the center. The subcrustal stretching factor ({delta}) ranges from 1.3 at the basin margin to more than 3.0 in the basin center. 31 refs., 13 figs., 4 tabs.« less

Paleoecology of the Devonian-Mississippian black-shale sequence in eastern Kentucky with an atlas of some common fossils

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barron, L.S.; Ettensohn, F.R.

The Devonian-Mississippian black-shale sequence of eastern North America is a distinctive stratigraphic interval generally characterized by low clastic influx, high organic production in the water column, anaerobic bottom conditions, and the relative absence of fossil evidence for biologic activity. The laminated black shales which constitute most of the black-shale sequence are broken by two major sequences of interbedded greenish-gray, clayey shales which contain bioturbation and pyritized micromorph invertebrates. The black shales contain abundant evidence of life from upper parts of the water column such as fish fossils, conodonts, algae and other phytoplankton; however, there is a lack of evidence ofmore » benthic life. The rare brachiopods, crinoids, and molluscs that occur in the black shales were probably epiplanktic. A significant physical distinction between the environment in which the black sediments were deposited and that in which the greenish-gray sediments were deposited was the level of dissolved oxygen. The laminated black shales point to anaerobic conditions and the bioturbated greenish-gray shales suggest dysaerobic to marginally aerobic-dysaerobic conditions. A paleoenvironmental model in which quasi-estuarine circulation compliments and enhances the effect of a stratified water column can account for both depletion of dissolved oxygen in the bottom environments and the absence of oxygen replenishment during black-shale deposition. Periods of abundant clastic influx from fluvial environments to the east probably account for the abundance of clays in the greenish-gray shale as well as the small amounts of oxygen necessary to support the depauparate, opportunistic, benthic faunas found there. These pulses of greenish-gray clastics were short-lived and eventually were replaced by anaerobic conditions and low rates of clastic sedimentation which characterized most of black-shale deposition.« less

Biothems: Sequence stratigraphic units and their implications for regional tectono-stratigraphic interpretations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lane, H.R.; Frye, M.W.; Couples, G.D.

1992-01-01

Biothems are regional wedge- or lens-shaped bodies of strata that are bounded shelfward or cratonward by paleontologically recognizable unconformities; generally thicken on marine shelves, where they are typically conformable with underlying and overlying biothems; are commonly thinner or represent starved sequences further basinward; and in their most basinward extent, are either bounded by biostratigraphically recognizable unconformities or are conformable with underlying and overlying biothems. As recognized to date, biothems have a logical distribution of faunal and floral components, as well as facies groupings that represent internally consistent and logical sequences of depositional environments. A west-to-east transect within the North Americanmore » Mississippian System which extends from the Basin and Range Province, across the Transcontinental Arch (TA), into the Anadarko Basin, was constructed to demonstrate the regional distribution and tectono-stratigraphic significance of biothems relative to the axis of the TA. The relationships portrayed on the transect, tied to an understanding of North American Mississippian paleogeography, imply that biothems deposited during relative highstand events on one flank of the TA are time-equivalent to biothems deposited during relative lowstand events on the opposite flank of the TA. This distribution is interpreted to have been controlled by intraplate tectonic events that formed piano key basins along the flanks of the TA. The spatial patterns of these basins are not consistent with published models of basin evolution. A further conclusion is that the lack of coincident, transgressive or regressive Mississippian biothems on either flank of the TA suggests that it is inadvisable to impose the Mississippi Valley-derived eustasy curve on western flank depositional sequences.« less

Stratigraphy and Petrology of the Grande Soufriere Hills Volcano, Dominica, Lesser Antilles

NASA Astrophysics Data System (ADS)

Daly, G.; Smith, A. L.; Garcia, R.; Killingsworth, N.

2007-12-01

The Grande Soufriere Hills volcanic center is located on the south east coast of the island of Dominica in the Lesser Antilles. Although the volcano is deeply dissected, a distinct circular crater that opens to the east can be observed. Within the crater is a lava dome and unconsolidated pyroclastic deposits mantle the southeast flanks of the volcano. These pyroclastic deposits are almost entirely matrix-supported block and ash flows and surges suggesting that Pelean-style eruptions have dominated its most recent activity. Within this sequence is a relatively thin (30-50 cm) clast-supported deposit that has been interpreted as a possible blast deposit. Two age dates from these younger deposits suggest that much of this activity occurred between l0,000 and 12,000 years ago. On the southeastern coast at Pointe Mulâtre and extending approximately 4 km north and at a maximum 2 km west, is a megabreccia of large (up to 3 m) flow-banded andesite clasts set in a semi-lithified medium grained ash matrix. At Pointe Mulâtre this megabreccia is overlain by unconsolidated block and ash flow deposits. To the north of the megabreccia, exposures in the sea cliffs reveal a consolidated sequence of well-bedded alternating coarse and fine deposits suggesting deltaic foreset beds; which in turn appears to be overlain by a yellow- colored relatively coarse flow deposit with an irregular upper surface. The uppermost deposits in the sea cliffs are a sequence of unconsolidated block and ash flow deposits and interbedded fluviatile conglomerates equivalent to the younger flow deposits logged inland. Volcanic rocks from the Grande Soufriere Hills are all porphyritic andesites often containing hypabyssal inclusions. Dominant phenocrysts are plagioclase often with inclusion-rich cores and well developed zoning. Mafic phenocrysts include hornblende, augite and hypersthene. Geochemically these andesites range from 58- 63% SiO2 and show trends of decreasing values for Al2O3, FeO, MgO, CaO, TiO2, Sr, V, and Sc and increasing values for Na2O, K2O, Ba, Rb, and Zr with increasing silica. Samples from the megabreccia can be chemically distinguished from the younger rocks of this center. Petrologic models suggest that the younger rocks from the Grand Soufriere Hills can be produced by fractional crystallization of basaltic magma such as those erupted from other centers (such as Morne Anglais to the west). Minor variations within this suite of andesites can be related to upper crustal fractionation of phenocryst phases.

Tracing sources of crustal contamination using multiple S and Fe isotopes in the Hart komatiite-associated Ni-Cu-PGE sulfide deposit, Abitibi greenstone belt, Ontario, Canada

NASA Astrophysics Data System (ADS)

Hiebert, R. S.; Bekker, A.; Houlé, M. G.; Wing, B. A.; Rouxel, O. J.

2016-10-01

Assimilation by mafic to ultramafic magmas of sulfur-bearing country rocks is considered an important contributing factor to reach sulfide saturation and form magmatic Ni-Cu-platinum group element (PGE) sulfide deposits. Sulfur-bearing sedimentary rocks in the Archean are generally characterized by mass-independent fractionation of sulfur isotopes that is a result of atmospheric photochemical reactions, which produces isotopically distinct pools of sulfur. Likewise, low-temperature processing of iron, through biological and abiotic redox cycling, produces a range of Fe isotope values in Archean sedimentary rocks that is distinct from the range of the mantle and magmatic Fe isotope values. Both of these signals can be used to identify potential country rock assimilants and their contribution to magmatic sulfide deposits. We use multiple S and Fe isotopes to characterize the composition of the potential iron and sulfur sources for the sulfide liquids that formed the Hart deposit in the Shaw Dome area within the Abitibi greenstone belt in Ontario (Canada). The Hart deposit is composed of two zones with komatiite-associated Ni-Cu-PGE mineralization; the main zone consists of a massive sulfide deposit at the base of the basal flow in the komatiite sequence, whereas the eastern extension consists of a semi-massive sulfide zone located 12 to 25 m above the base of the second flow in the komatiite sequence. Low δ56Fe values and non-zero δ34S and Δ33S values of the komatiitic rocks and associated mineralization at the Hart deposit is best explained by mixing and isotope exchange with crustal materials, such as exhalite and graphitic argillite, rather than intrinsic fractionation within the komatiite. This approach allows tracing the extent of crustal contamination away from the deposit and the degree of mixing between the sulfide and komatiite melts. The exhalite and graphitic argillite were the dominant contaminants for the main zone of mineralization and the eastern extension zone of the Hart deposit, respectively. Critically, the extent of contamination, as revealed by multiple S and Fe isotope systematics, is greatest within the deposit and decreases away from it within the komatiite flow. This pattern points to a local source of crustal contamination for the mantle-derived komatiitic melt and a low degree of homogenization between the mineralization and the surrounding lava flow. Coupled S and Fe isotope patterns like those identified at the Hart deposit may provide a useful tool for assessing the potential of a komatiitic sequence to host Ni-Cu-(PGE).

Molecular Analysis of Carbon Monoxide-Oxidizing Bacteria Associated with Recent Hawaiian Volcanic Deposits†

PubMed Central

Dunfield, Kari E.; King, Gary M.

2004-01-01

Genomic DNA extracts from four sites at Kilauea Volcano were used as templates for PCR amplification of the large subunit (coxL) of aerobic carbon monoxide dehydrogenase. The sites included a 42-year-old tephra deposit, a 108-year-old lava flow, a 212-year-old partially vegetated ash-and-tephra deposit, and an approximately 300-year-old forest. PCR primers amplified coxL sequences from the OMP clade of CO oxidizers, which includes isolates such as Oligotropha carboxidovorans, Mycobacterium tuberculosis, and Pseudomonas thermocarboxydovorans. PCR products were used to create clone libraries that provide the first insights into the diversity and phylogenetic affiliations of CO oxidizers in situ. On the basis of phylogenetic and statistical analyses, clone libraries for each site were distinct. Although some clone sequences were similar to coxL sequences from known organisms, many sequences appeared to represent phylogenetic lineages not previously known to harbor CO oxidizers. On the basis of average nucleotide diversity and average pairwise difference, a forested site supported the most diverse CO-oxidizing populations, while an 1894 lava flow supported the least diverse populations. Neither parameter correlated with previous estimates of atmospheric CO uptake rates, but both parameters correlated positively with estimates of microbial biomass and respiration. Collectively, the results indicate that the CO oxidizer functional group associated with recent volcanic deposits of the remote Hawaiian Islands contains substantial and previously unsuspected diversity. PMID:15240307

High Resolution Climatic Variations Recorded by Mollusk Fauna at Nussloch (Rhine Valley, Germany) During the Last Glaciation

NASA Astrophysics Data System (ADS)

Moine, O.; Rousseau, D.; Antoine, P.

2002-12-01

During the last 31 and 19 kyr interval important eolian sediment deposited in Western Europe at Nussloch (Rhine Valley, Germany) favored by the enhanced atmospheric circulation at mid-latitudes and large areas of deflation providing quantities of material such as the English Channel, the North Sea or the dry Rhine valley. The 10m-high studied sequence is composed of an alternation of nine gley-loess cycles. Except for few adjoining assemblages, the composition of the malacofauna is almost constant all along the sequence and typical of a humid loess facies and a steppe environment. Each cycle is composed of three parts. The first is the deposit of loess in windy, dry and cold climate, with associated malacofauna in equilibrium with these conditions. The second is the development of a gley in a colder and more humid context, with a very reduced particle deposition and, in the first half of the sequence, the presence of a permafrost. The associated malacofauna are characterized by a more or less important decrease in the diversity and equitability indicating the influence of a climatic drop. The third part is not characterized by any particular deposit, but by the thaw of the permafrost, when it is present, and by a demographic explosion of the mollusk fauna if the climate is not too dry. Such lithological alternations have been evidenced in all the Late Pleistocene deposits in Western Europe. They suggest that global climatic variations had a strong influence on the continental domain in Europe during this interval. Precedent results obtained from this site have shown that the variations in a grain size index can be correlated with those of the dust content recorded in the GRIP ice-core, both being influenced by the eolian dynamics. Thus, the timescale of the GRIP ice-core has been applied to the loess sequence of Nussloch, and allowed us the comparison of our mollusk index with the d18O of the GRIP core. From this correlation it appears that the abundance in terrestrial mollusks fits the d18O variations in the ice-core supporting that the high biological abundance regularly occurring in the sequence would due to climate ameliorations and not related to sedimentological artifacts. Nevertheless the strong dryness occurring in the upper part of the sequence, and indicated by both the mollusk species richness and the d13C of the organic matter of the soil, seems to have restrained the development of the malacofauna, preventing the malacofauna to record any climatic improvement during this period.

Temporal evolution of bacterial communities associated with the in situ wetland-based remediation of a marine shore porphyry copper tailings deposit.

PubMed

Diaby, N; Dold, B; Rohrbach, E; Holliger, C; Rossi, P

2015-11-15

Mine tailings are a serious threat to the environment and public health. Remediation of these residues can be carried out effectively by the activation of specific microbial processes. This article presents detailed information about temporal changes in bacterial community composition during the remediation of a section of porphyry copper tailings deposited on the Bahía de Ite shoreline (Peru). An experimental remediation cell was flooded and transformed into a wetland in order to prevent oxidation processes, immobilizing metals. Initially, the top oxidation zone of the tailings deposit displayed a low pH (3.1) and high concentrations of metals, sulfate, and chloride, in a sandy grain size geological matrix. This habitat was dominated by sulfur- and iron-oxidizing bacteria, such as Leptospirillum spp., Acidithiobacillus spp., and Sulfobacillus spp., in a microbial community which structure resembled acid mine drainage environments. After wetland implementation, the cell was water-saturated, the acidity was consumed and metals dropped to a fraction of their initial respective concentrations. Bacterial communities analyzed by massive sequencing showed time-dependent changes both in composition and cell numbers. The final remediation stage was characterized by the highest bacterial diversity and evenness. Aside from classical sulfate reducers from the phyla δ-Proteobacteria and Firmicutes, community structure comprised taxa derived from very diverse habitats. The community was also characterized by an elevated proportion of rare phyla and unaffiliated sequences. Numerical ecology analysis confirmed that the temporal population evolution was driven by pH, redox, and K. Results of this study demonstrated the usefulness of a detailed follow-up of the remediation process, not only for the elucidation of the communities gradually switching from autotrophic, oxidizing to heterotrophic and reducing living conditions, but also for the long term management of the remediation wetlands. Copyright © 2015 Elsevier B.V. All rights reserved.

Eustatic sea level fluctuations induced by polar wander

NASA Technical Reports Server (NTRS)

Sabadini, Roberto; Doglioni, Carlo; Yuen, David A.

1990-01-01

It is shown here that polar wander of a viscoelastic, stratified earth can induce global sea level fluctuations comparable to the short-term component in eustatic sea-level curves. The sign of these fluctuations, which are very sensitive to the rheological stratification, depends on the geographical location of the observation point; rises and falls in sea level can thus be coeval in different parts of the world. This finding is a distinct contrast to the main assumption underlying the reconstruction of eustatic curves, namely that global sea-level events produce the same depositional sequence everywhere. It is proposed that polar wander should be added to the list of geophysical mechanisms that can control the third-order cycles in sea level.

Detection of aneurysmal subarachnoid hemorrhage 3 months after initial bleeding: evaluation of T2* and FLAIR MR sequences at 3 T in comparison with initial non-enhanced CT as a gold standard.

PubMed

Mulé, Sébastien; Soize, Sébastien; Benaissa, Azzedine; Portefaix, Christophe; Pierot, Laurent

2016-08-01

To investigate the ability of T2* and fluid-attenuated inversion recovery (FLAIR) MR sequences to detect hemosiderin deposition 3 months after aneurysmal subarachnoid hemorrhage (SAH) in comparison with early non-enhanced CT (NECT) as a gold standard. From September 2008 through May 2013, patients with aneurysmal SAH were included if a NECT less than 24 h after the onset of symptoms showed a SAH, and MRI, including T2* and FLAIR sequences, was performed 3 months later. All aneurysms were treated endovascularly. NECT and MR sequences were blindly analyzed for the presence of SAH (NECT) or hemosiderin deposition (MRI). When positive, details of the spatial distribution of SAH or hemosiderin deposits were noted. Sensitivities were calculated for each patient. Sensitivities, specificities, and positive predictive values (PPVs) were calculated for each location. Forty-nine patients (mean age 52.9 years) were included. Bleeding-related patterns were identified in 43 patients (87.8%) on T2* and 10 patients (20.4%) on FLAIR. T2* was highly predictive of the location of the initial hemorrhage, especially in the Sylvian cisterns (PPVs 95% and 100%) and the anterior interhemispheric fissure (PPV 90%). The T2* sequence can detect and localize a previous SAH a few months after aneurysmal bleeding. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

USGS Publications Warehouse

Farrell, K.M.

2001-01-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions - vertical (x), lateral (y), and down-the-basin (z). A flood basin fills in as landforms vertically (x) and laterally accrete (y), and prograde down-the-basin (z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution. ?? 2001 Elsevier Science B.V. All rights reserved.

Geomorphology, facies architecture, and high-resolution, non-marine sequence stratigraphy in avulsion deposits, Cumberland Marshes, Saskatchewan

NASA Astrophysics Data System (ADS)

Farrell, K. M.

2001-02-01

This paper demonstrates field relationships between landforms, facies, and high-resolution sequences in avulsion deposits. It defines the building blocks of a prograding avulsion sequence from a high-resolution sequence stratigraphy perspective, proposes concepts in non-marine sequence stratigraphy and flood basin evolution, and defines the continental equivalent to a parasequence. The geomorphic features investigated include a distributary channel and its levee, the Stage I crevasse splay of Smith et al. (Sedimentology, vol. 36 (1989) 1), and the local backswamp. Levees and splays have been poorly studied in the past, and three-dimensional (3D) studies are rare. In this study, stratigraphy is defined from the finest scale upward and facies are mapped in 3D. Genetically related successions are identified by defining a hierarchy of bounding surfaces. The genesis, architecture, geometry, and connectivity of facies are explored in 3D. The approach used here reveals that avulsion deposits are comparable in process, landform, facies, bounding surfaces, and scale to interdistributary bayfill, i.e. delta lobe deposits. Even a simple Stage I splay is a complex landform, composed of several geomorphic components, several facies and many depositional events. As in bayfill, an alluvial ridge forms as the feeder crevasse and its levees advance basinward through their own distributary mouth bar deposits to form a Stage I splay. This produces a shoestring-shaped concentration of disconnected sandbodies that is flanked by wings of heterolithic strata, that join beneath the terminal mouth bar. The proposed results challenge current paradigms. Defining a crevasse splay as a discrete sandbody potentially ignores 70% of the landform's volume. An individual sandbody is likely only a small part of a crevasse splay complex. The thickest sandbody is a terminal, channel associated feature, not a sheet that thins in the direction of propagation. The three stage model of splay evolution proposed by Smith et al. (Sedimentology, vol. 36 (1989) 1) is revised to include facies and geometries consistent with a bayfill model. By analogy with delta lobes, the avulsion sequence is a parasequence, provided that its definition is modified to be independent from sea level. In non-marine settings, facies contacts at the tops of regional peats, coals, and paleosols are analogous to marine flooding surfaces. A parasequence is redefined here as a relatively conformable succession of genetically related strata or landforms that is bounded by regional flooding surfaces or their correlative surfaces. This broader definition incorporates the concept of landscape evolution between regional flooding surfaces in a variety of depositional settings. With respect to landscape evolution, accommodation space has three spatial dimensions — vertical ( x), lateral ( y), and down-the-basin ( z). A flood basin fills in as landforms vertically ( x) and laterally accrete ( y), and prograde down-the-basin ( z). Vertical aggradation is limited by the elevation of maximum flood stage (local base level). Differential tectonism and geomorphology control the slope of the flood basin floor and the direction of landscape evolution. These processes produce parasequences that include inclined stratal surfaces and oriented, stacked macroforms (clinoforms) that show the magnitude and direction of landscape evolution.

Wild Birds Use an Ordering Rule to Decode Novel Call Sequences.

PubMed

Suzuki, Toshitaka N; Wheatcroft, David; Griesser, Michael

2017-08-07

The generative power of human language depends on grammatical rules, such as word ordering, that allow us to produce and comprehend even novel combinations of words [1-3]. Several species of birds and mammals produce sequences of calls [4-6], and, like words in human sentences, their order may influence receiver responses [7]. However, it is unknown whether animals use call ordering to extract meaning from truly novel sequences. Here, we use a novel experimental approach to test this in a wild bird species, the Japanese tit (Parus minor). Japanese tits are attracted to mobbing a predator when they hear conspecific alert and recruitment calls ordered as alert-recruitment sequences [7]. They also approach in response to recruitment calls of heterospecific individuals in mixed-species flocks [8, 9]. Using experimental playbacks, we assess their responses to artificial sequences in which their own alert calls are combined into different orderings with heterospecific recruitment calls. We find that Japanese tits respond similarly to mixed-species alert-recruitment call sequences and to their own alert-recruitment sequences. Importantly, however, tits rarely respond to mixed-species sequences in which the call order is reversed. Thus, Japanese tits extract a compound meaning from novel call sequences using an ordering rule. These results demonstrate a new parallel between animal communication systems and human language, opening new avenues for exploring the evolution of ordering rules and compositionality in animal vocal sequences. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stratigraphic palaeobiology around the Pliocene-Pleistocene boundary at Altavilla Milicia (Sicily, Italy)

NASA Astrophysics Data System (ADS)

Dominici, Stefano; Benvenuti, Marco; Garilli, Vittorio; Uchman, Alfred; Pollina, Francesco

2017-04-01

The Pliocene-Pleistocene around Altavilla Milicia, near Palermo (Sicily), includes a thick siliciclastic succession rich with shell beds, dominated by molluscs, brachiopods and annelids in fine-grained, totally bioturbated sandstones. Taphonomy of fossil assemblages indicates the importance of taphonomic feedback and within-habitat time-averaging in proximity of maximum flooding intervals. The trace fossil suite is characterized by the abundance of Thalassinoides paradoxicus boxworks and by local occurence of Scalichnus, Piscichnus, ?Scolicia, ?Bichordites, Ophiomorpha, ?Gyrolithes, Palaeophycus, Diopatrichnus and ?Taenidium. These trace fossils are typical of the archetypal Cruziana ichnofacies, with local elements of the proximal Cruziana ichnofacies, which point to deposition mainly below the fairweather wave base. Three depositional sequences, characterized by geometries driven by the interplay of eustatism and regional tectonics, were recognized through sedimentary facies analysis. Biostratigraphic data frame the oldest sequence in the upper Pliocene, whereas the thickest part of the succession, occupied by the second sedimentary sequence, includes biozone NN16b/17 of calcareous nannoplankton stratigraphy, thereby comprising the base of the Pleistocene. Transgressive deposits of the third and uppermost sequence are marked by encrusted and bioeroded pebbles with sparse oyster shells. The whole time interval is characterized by glacio-eustatic fluctuations in the 50-100 m range and with 100 ky-periodicity. We performed a multivariate analysis of 22 samples yielding 92 species of mollusks collected in the first and second sequences. Clustering and ordination analysis allowed to recognize a gradient controlled by depth-related environmental variables. At one end of the continuum we have a very-shallow water assemblage dominated by the bivalve Loripes orbiculatus, indicating an organic-rich seagrass bottom. Opposite in the continuum is an offshore assemblage dominated by Corbula gibba and the extinct gastropod Petaloconchus intortus. Both the shallowest and the deepest assemblages are from the first (Piacenzian) sequence. The gradient at intermediate depths is better characterized by restricting the analysis to 17 collections from the second sequence (Piacenzian-Gelasian). The shallowest assemblage is here dominated by upper shoreface species, such as Tellina spp. and Spisula subtruncata, and the deepest by muddy bottom, offshore transition species, such as Venus nux, the extinct gastropod Nassarius semistriatus and deposit-feeding nuculanoid bivalves. Plotting samples along the composite section allows to recognize two deepening-upward trends and two intervals of maximum flooding, in accordance with the sequence-stratigraphic interpretation. Stratigraphic palaeobiology proves to be a powerful tool to understand factors that control the geologic record during an interval of intense climate change.

Stratigraphy and erosional landforms of layered deposits in Valles Marineris, Mars

NASA Technical Reports Server (NTRS)

Komatsu, G.; Geissler, P. E.; Strom, R. G.; Singer, R. B.

1993-01-01

Satellite imagery is used to identify stratigraphy and erosional landforms of 13 layered deposits in the Valles Marineris region of Mars (occurring, specifically, in Gangis, Juventae, Hebes, Ophir-Candor, Melas, and Capri-Eos Chasmata), based on albedo and erosional styles. Results of stratigraphic correlations show that the stratigraphy of layered deposits in the Hebes, Juventae, and Gangis Chasmata are not well correlated, indicating that at least these chasmata had isolated depositional environments resulting in different stratigraphic sequences. On the other hand, the layered deposits in Ophir-Candor and Melas Chasmata appear to have been connected in each chasma. Some of the layered deposits display complexities which indicate changes in space and time in the dominant source materials.

Towards a volcanic-structural balance: relative importance of volcanism, folding, and remobilisation of nickel sulphides at the Perseverance Ni-Cu-(PGE) deposit, Western Australia

NASA Astrophysics Data System (ADS)

Duuring, Paul; Bleeker, Wouter; Beresford, Steve W.; Hayward, Nicholas

2010-03-01

Perseverance is a world-class, komatiite-hosted nickel sulphide deposit situated in the well-endowed Leinster nickel camp of the Agnew-Wiluna greenstone belt, Western Australia. The mine stratigraphy at Perseverance trends north-northwest (NNW), dips steeply to the west, and is overturned. Stratigraphic footwall units lie along the western margin of the Perseverance Ultramafic Complex (PUC). The PUC comprises a basal nickel sulphide-bearing orthocumulate- to mesocumulate-textured komatiite that is overlain by a thicker, nickel sulphide-poor, dunite lens. Hanging wall rocks include rhyodacite that is texturally and compositionally similar to footwall volcanic rocks. These rocks separate the PUC from a second sequence of nickeliferous, E-facing, spinifex-textured komatiite units (i.e. the East Perseverance komatiite). Past workers argue for a conformable stratigraphic contact between the PUC and the East Perseverance komatiite and conclude that the PUC is extrusive. This study, however, clearly demonstrates that these komatiite sequences are discordant, implying that the PUC may have intruded rhyodacite country rock as a sill with subsequent structural juxtaposition against the East Perseverance komatiite. Early N-S shortening associated with the regional DI deformation event (corresponding to the local DP1 to DP3 events at Perseverance) resulted in the heterogeneous partitioning of strain along the margins of the competent dunite. A mylonite developed in the more ductile footwall rocks along the footwall margin of the PUC, while isoclinal F3 folds, such as the Hanging wall limb and Felsic Nose folds, formed in low-mean stress domains along the fringes of the elongated dunite lens. Strata-bound massive and disseminated nickel sulphides were passively fold thickened in hinge areas of isoclinal folds, whereas basal massive sulphides lubricated fold limbs and promoted thrust movement along shallowly dipping lithological contacts. Massive sulphides were physically remobilised up to 20 m from their primary footwall position into deposit-scale fold hinges to form the 1A and Felsic Nose orebodies. First-order controls on the geometry of the Perseverance deposit include the thermomechanical erosion of footwall rocks and the channelling of the mineralised komatiitic magma. Second- or third-order controls are several postvolcanic deformation events, which resulted in the progressive folding and shearing of the footwall contact, as well as the passive fold thickening of massive and disseminated sulphide orebodies. Massive sulphides were physically remobilised into multiple generations of fold hinges and shear zones. Important implications for near-mine exploration in the Leinster camp include identifying nickeliferous komatiite units, defining their three-dimensional geometry, and targeting fold hinge areas. Fold plunge directions and stretching lineations are indicators of potential plunge directions of massive sulphide orebodies.

Subaqueous Tsunami Deposits from Ohtsuchi Bay of Sanriku Coast, North Eastern Japan

NASA Astrophysics Data System (ADS)

Haraguchi, T.; Fujiwara, O.; Shimazaki, K.

2005-12-01

Holocene tsunami history was analyzed by using a drilling core obtained from the Ohtsuchi Bay on the Sanriku coast, Pacific side of NE Japan. The saw-tooth Sanriku coast line, facing the Japan Trench, is well known for repeated suffers from the historical great tsunamis. The worst tsunami damage in Japanese history, more than 20,000 fatalities, by the AD1896 Meiji Sanriku Tsunami (M 8 1/2) centered off Sanriku was recorded from this coast. However, the geological records of ancient tsunami such as tsunami deposits have been rarely reported from the Sanriku coast.Reconstruction of the pale-tsunami history including the recurrence interval is fundamental data for the tsunami disaster mitigation on the coast. The core, 24-meter long, obtained from a bay center of 10 m-deep is mainly composed of sandy mud excluding the basal gravel bed (core bottom reached SL-34 m). Sand and gravelly sand beds ranging from several to 200 cm-thick are intercalated in the core and denoted TS-22 to TS-1 in ascending order. Most of these coarse-grained beds have evidences of deposition from high-energy and density currents, basal erosion surface, rip-up clasts mixed mulluscan shells, inverse- and normal grading, and generally upward-fining sequence.Most likely origin of these event deposits is great tsunami, because the coring site is a deep and low energy bay floor isolated from major river mouth. Low sediment supply by river floods and small disturbance by wind waves at the drilling site are favorable for the preservation of tsunami deposits. Depositional ages of TS-1 to TS-22 were estimated from a depositional curve of the core based on ten 14C ages of marine shells. Recurrence interval of 13 sand and gravel beds in the lower part of the core, TS22 (ca. 7800 cal BP) to TS-10 (AD1660-1700), is 400 to 500 years.The number of event beds in the upper part of the core, deposited during the last 400 years (TS-9 to TS-1), approximates to that of historic large tsunamis recorded around the Ohtsuchi Bay (13-14 times).Remarkable differences of the recurrence intervals of event deposits between the lower and upper parts of the core reflects the change of sediment supply system and preservation potential of the event deposits.Identification of tsunami deposits from other deposits such as river flood and storm deposits is problem to be solved for reconstructing the accurate tsunami history on the Sanriku coast.

Pure and Sn-doped ZnO films produced by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Holmelund, E.; Schou, J.; Tougaard, S.; Larsen, N. B.

2002-09-01

A new technique, metronome doping, has been used for doping of films during pulsed laser deposition (PLD). This technique makes it possible to dope continuously during film growth with different concentrations of a dopant in one deposition sequence. Films of pure and doped ZnO have been produced with Sn concentrations up to 16%. The specific resistivity is found to increase and the transmission of visible light to decrease with increasing Sn concentration.

Heteroepitaxial growth of 3-5 semiconductor compounds by metal-organic chemical vapor deposition for device applications

NASA Technical Reports Server (NTRS)

Collis, Ward J.; Abul-Fadl, Ali

1988-01-01

The purpose of this research is to design, install and operate a metal-organic chemical vapor deposition system which is to be used for the epitaxial growth of 3-5 semiconductor binary compounds, and ternary and quaternary alloys. The long-term goal is to utilize this vapor phase deposition in conjunction with existing current controlled liquid phase epitaxy facilities to perform hybrid growth sequences for fabricating integrated optoelectronic devices.

Sedimentary facies analysis of the Mesozoic clastic rocks in Southern Peru (Tacna, 18°S): Towards a paleoenvironmental Redefinition and stratigraphic Reorganization

NASA Astrophysics Data System (ADS)

Alván, Aldo; Jacay, Javier; Caracciolo, Luca; Sánchez, Elvis; Trinidad, Inés

2018-07-01

The Mesozoic rocks of southern Peru comprise a Middle Jurassic to Early Cretaceous sedimentary sequence deposited during a time interval of approximately 34 Myr. In Tacna, these rocks are detrital and constitute the Yura Group (Callovian to Tithonian) and the Hualhuani Formation (Berriasian). Basing on robust interpretation of facies and petrographic analysis, we reconstruct the depositional settings of such units and provide a refined stratigraphic framework. Accordingly, nine types of sedimentary facies and six architectural elements are defined. They preserve the record of a progradational fluvial system, in which two styless regulated the dispersion of sediments: (i) a high-to moderate-sinuosity meandering setting (Yura Group), and a later (ii) incipient braided setting (Hualhuani Formation). The Yura Group (Callovian-Tithonian) represents the onset of floodplain deposits and lateral accretion of point-bar deposits sited on a semi-flat topography. Nonetheless, the progradational sequence was affected by at least two rapid marine ingressions occurred during Middle Callovian and Tithonian times. Such marine ingressions reveal the proximity of a shallow marine setting and incipient carbonate deposition. In response to increase in topographic gradient, the Hualhuani Formation (Berriasian) deposited as extensive multistory sandy channels. The mineralogy of the Mesozoic sediments suggests sediment supplies and intense recycling from a craton interior (i.e. Amazon Craton and/or plutonic sources) located eastward of the study area.

Molecular confirmation of Hepatozoon canis in Mauritius.

PubMed

Daskalaki, Aikaterini Alexandra; Ionică, Angela Monica; Jeetah, Keshav; Gherman, Călin Mircea; Mihalca, Andrei Daniel

2018-01-01

In this study, Hepatozoon species was molecularly identified and characterized for the first time on the Indian Ocean island of Mauritius. Partial sequences of the 18S rRNA gene of the Hepatozoon isolates were analysed from three naturally infected dogs. The sequences of H. canis were similar to the 18S rRNA partial sequences (JX112783, AB365071 99%) from dog blood samples from West Indies and Nigeria. Our sequences were deposited in the GenBank database. Copyright © 2017 Elsevier B.V. All rights reserved.

Preliminary examination of uranium deposits near Marysvale, Piute County, Utah

USGS Publications Warehouse

Granger, Harry C.; Bauer, Herman L.

1950-01-01

Autunite and other uranium minerals were discovered in 1948 by Pratt Seegmiller about 3 1/4 miles north of Marysvale, Piute County, Utah. Mining operations were begun in the summer of 1949 by the Vanadium Corporation of America on the Prospector and the Freedom claims, and by the Bullion Monarch Mining Company a the Bullion Monarch claims. These claims were examined briefly in December 1949 and January 1950 by the writers. The uranium deposits of the Marysvale district are in north-easterly striking fault zones in quartz monzonite that intrudes rocks of the "older" Tertiary volcanic sequence. Flows and tuffs of the "younger" Tertiary volcanic sequence uncomfortably overlie the earlier rocks. Autunite, tobernite, uranophane, schroeckingerite, and at least one unidentified secondary uranium mineral occur in the upper parts of the deposits. Pitchblende has been mined from the underground workings of the Prospector No. 1 mine. The uranium minerals are associated with dense quartz veins and intensely argillized wall rock. In the upper parts of the deposits pyrite is completely oxidized. The secondary uranium minerals probably were formed by the alteration of primary pitchblende by circulating meteoric waters.

Sequence stratigraphy on an early wet Mars

NASA Astrophysics Data System (ADS)

Barker, Donald C.; Bhattacharya, Janok P.

2018-02-01

The evolution of Mars as a water-bearing body is of considerable interest for the understanding of its early history and evolution. The principles of terrestrial sequence stratigraphy provide a useful conceptual framework to hypothesize about the stratigraphic history of the planets northern plains. We present a model based on the hypothesized presence of an early ocean and the accumulation of lowland sediments eroded from highland terrain during the time of the valley networks and later outflow channels. Ancient, global environmental changes, induced by a progressively cooling climate would have led to a protracted loss of surface and near surface water from low-latitudes and eventual cold-trapping at higher latitudes - resulting in a unique and prolonged, perpetual forced regression within basins and lowland depositional environments. The Messinian Salinity Crisis (MSC) serves as a potential terrestrial analogue of the depositional and environmental consequences relating to the progressive removal of large standing bodies of water. We suggest that the evolution of similar conditions on Mars would have led to the emplacement of diagnostic sequences of deposits and regional scale unconformities, consistent with intermittent resurfacing of the northern plains and the progressive loss of an early ocean by the end of the Hesperian era.

Measurement of dew droplets in initial deposition at dew point by using a phase-shift interference microscope

NASA Astrophysics Data System (ADS)

Matsumoto, Shigeaki; Toyooka, Satoru; Hoshino, Mitsuo

2002-09-01

In order to measure the total mass per unit area of dew droplets deposited on a metal plate in the dew-point hygrometer, the shape of a dew droplet deposited on a copper plate was measured accurately by using an interference microscope that employed a phase-shift technique. The microscope was constructed by adding a piezoelectric transducer to an usual interference microscope. A simple method that uses a conventional speaker horn and an optical fiber cable was introduced to depress speckle noise. The shape of a dew droplet deposited on the copper plate surface with 0.1 μm in average roughness was measured with an accuracy of +/-3nm. The mass of a dew droplet could be calculated numerically from the volume of its shape and was of the order of 10-9 g. The total mass of dew droplets deposited per unit area and the deposition velocity were obtained under a gentle wind. The total mass was the order of 10-5 g/cm2 at the beginning of deposition and the deposition velocity was ranged from 2x10-6 to 6x10-5 g/cm2.min.

Past sea-level data from Lakse Bugt, Disko Island, West Greenland from ground-penetrating radar data

NASA Astrophysics Data System (ADS)

Souza, Priscila E.; Nielsen, Lars; Kroon, Aart; Clemmensen, Lars B.

2016-04-01

Beach-ridge deposits have been used as sea-level indicators in numerous studies from temperate coastal regions. However, their present surface morphology in artic regions may not accurately correspond to past sea-level, because subsequent surface erosion, solifluction processes and/or later sediment deposition may have altered the surface significantly. The internal structure of these beach ridges, however, is often well-preserved and thus constitutes an important key to reconstruction of past sea levels as seen elsewhere. In the present study, high-resolution reflection GPR data and high-precision topographic data were collected at Lakse Bugt (Disko Island, West Greenland) using a shielded 250 MHz antennae system and a RTK-Trimble R8 DGPS, respectively. Three transects were collected across a sequence of fossil, raised beach ridge deposits, and two transects were obtained across modern beach deposits at the shoreline of the mesotidal regime. Along all radar profiles we observed downlap reflection points, which we interpret to represent the boundary between sediments deposited on the beachface and sediments deposited in the upper shoreface regime. Both the upper shoreface and the beachface deposits exhibit reflection patterns dipping in the seaward direction. The beachface deposits show the strongest dip. At or just below the downlap points strong diffractions are often observed indicating the presence of a layer containing stones. These stones are large enough to generate significant signal scattering. At the present day beach a sharp transition defined by the presence of large stones is observed near the low tide water level: cobbles characterize the seaside, while the land side is characterized by sand and gravel. Therefore, it seems reasonable to conclude that downlap points observed in the GPR data serve as indicators of past low-tide levels (at the time of deposition). The downlap points show a consistent offset with respect to present surface topography indicating that the beach ridge deposits are well-preserved in our study area. Samples taken for OSL dating have not been dated yet. Instead, a first order age model for the investigated area is based on extrapolation of dating made by others at different sites on Disko Island. This extrapolated age model is used in a first attempt to reconstruct relative sea-level change at Lakse Bugt.

First characterisation of the "Rumi-Pana" rock avalanche deposits (Famatina Range, La Rioja, Argentina)

NASA Astrophysics Data System (ADS)

Santiago Pullarello, José; Derron, Marc-Henri; Penna, Ivanna; Leiva, Alicia; Jaboyadoff, Michel

2017-04-01

Active mountain fronts are subject to large scale slope collapses which have the capacity to run long distances on piedmont areas. Along time, fluvial activity and other gravitatory processes can intensively erode and mask primary features related to the collapses. Therefore, to reconstruct the history of their occurrence, further analyses are needed, e.g. sedimentologic analyses. This work focuses on the occurrence of large rock avalanches in the Vinchina region, La Rioja (28°43'27.81'' S / 68°00'25.42'' W) on the western side of the Famatina range(Argentina). Here, photointerpretation of high resolution satellite images (Google Earth) allowed us to identify two rock avalanches, main scarps developed at 2575 and 2750 m a.s.l. . There are no absolute ages for these deposits, however, comparing their preservation degree with those dated further north (in similar climatic and landscape dynamics contexts [i]), we can suggest these rock avalanches took place during the Pleistocene. We carried out a fieldwork survey in this remote area, including classical landslide mapping, structural analysis, deposits characterization and sampling. The deposits reach the valley bottom (at around 1700 m a.s.l.) with runouts about 5 and 5.3 km long. In one of the cases, the morphology of the deposit is well preserved, allowing to reconstruct accurately its extension. However, in the second case, the deposits are strongly eroded by courses draining the mountain front, therefore further analyses should be done to reconstruct its extension. In addition to morphologic interpretations, a multiscale grain-size analysis was done to differentiate rock avalanches from other hillslope deposits: (1) 3D surface models of surface plots (5x5m) have been built by SfM photogrammetry; 2) classical sieving and 3) laser grain-size analysis of deposits. Samples were collected on different parts of the slope, but also along cross sections through the avalanche deposit. This deposits characterization will be combined with results from mapping and image analysis in order to provide a first description of the sequence and extension of events related to the evolution of this mountain front. [i] Hermanns et Strecker, Structural and lithological controls on large Quaternary rock avalanches (sturzstroms) in arid northwestern Argentina, Geological Society of America Bulletin 1999.

Volcanic Hazards Associated with the NE Sector of Tacaná Volcano, Guatemala.

NASA Astrophysics Data System (ADS)

Hughes, S. R.; Saucedo, R.; Macias, J.; Arce, J.; Garcia-Palomo, A.; Mora, J.; Scolamacchia, T.

2003-12-01

Tacaná volcano, with a height of 4,030 m above sea level, straddles the southern Mexico/Guatemala border. Last active in 1986, when there was a small phreatic event with a duration of a few days, this volcano presents an impending hazard to over 250,000 people. The NE sector of the volcano reveals the violent volcanic history of Tacaná that may be indicative of a serious potential risk to the area. Its earliest pyroclastic history appears to consist of fall, flow, and surge deposits, together with lavas, that have formed megablocks within a series of old debris avalanche deposits. This sector collapse event is overlain by a sequence of pumice fall and ash flow deposits, of which the youngest, less-altered pumice fall deposit shows a minimum thickness of > 4 m, with a dispersal axis trending toward the NE. A second debris avalanche deposit, separated from the above deposits by a paleosoil, is dominated by megablocks of lava and scoriaceous dome material. The current topography around the northeastern flank of the volcano is determined by a third, and most recent debris avalanche deposit, a thick (> 20 m) sequence of six block and ash flows dated at around 16,000 years BP, each separated by 1-10 cm thick ash cloud surge deposit, together with secondary lahar deposits. These are followed by a at least 4 lava flows that extend 2 km down the flank of the volcano. It appears that the most recent pyroclastic event at Tacaná is also recorded in this sector of the volcano: above the block and ash flows occurs a > 1 m thick ash flow unit that can be seen at least 5 km from the vent. Lastly, the Santa Maria Ash fall deposit, produced in 1902, has capped most of the deposits at Tacaná.

Quartz and K-feldspar luminescence dating of sedimentation in the North Bohai coastal area (NE China) since the late pleistocene

NASA Astrophysics Data System (ADS)

Li, Yan; Shang, Zhiwen; Tsukamoto, Sumiko; Tamura, Toru; Yi, Liang; Wang, Hong; Frechen, Manfred; Li, Jianfen; Jiang, Xingyu

2018-02-01

In this study, luminescence dating of core sediments from the North Bohai Coast (China) was applied to provide a high-resolution chronological constraint, on a better understanding of the Holocene marine-terrestrial interaction. The studied sedimentary sequence contains a terrigenous deposit, a transgressive deposit and a prograding deltaic succession; all are believed to have formed during the late Pleistocene. To establish a reliable luminescence chronology, the luminescence signals of ten samples were investigated in order to quantify the degree of bleaching. This approach involved the use of quartz OSL, K-feldspar infrared stimulated luminescence (IRSL) and post-IR IRSL (pIRIR) ages. The resulting data were then compared with radiocarbon ages. The quartz OSL signals were well-bleached for all the samples, and the feldspar pIRIR150 and pIRIR225 signals yielded reliable ages for the pre-Holocene deposits but overestimated ages for late Holocene deposits (<1000 years). Radiocarbon data appeared to slightly overestimate the age of the young Holocene samples, therefore the chronological framework was established using quartz OSL ages. The early-mid Holocene transgressive deposits are relatively thin, which was attributed to the low-gradient relief and weak riverine fluvial input. Rapid deltaic progradation with high sedimentation rates over the last millennia, was revealed by the quartz OSL age results. This was supported by historical records for this section of the coastline. Episodic deposition around 700 years ago most likely triggered by frequent flooding events, was highlighted by the clustered OSL ages. While the sediment increment was 2.7 × 104 m3 a-1 for the period of ∼6-1 ka, this increased considerably to 9.1 × 106 m3 a-1 during the rapid progradation of the last millennium. The increase appears related to winter monsoon enhancement and human activity during the last 1000 years.

Transcriptomic Analysis Identifies Candidate Genes Related to Intramuscular Fat Deposition and Fatty Acid Composition in the Breast Muscle of Squabs (Columba)

PubMed Central

Ye, Manhong; Zhou, Bin; Wei, Shanshan; Ding, MengMeng; Lu, Xinghui; Shi, Xuehao; Ding, Jiatong; Yang, Shengmei; Wei, Wanhong

2016-01-01

Despite the fact that squab is consumed throughout the world because of its high nutritional value and appreciated sensory attributes, aspects related to its characterization, and in particular genetic issues, have rarely been studied. In this study, meat traits in terms of pH, water-holding capacity, intramuscular fat content, and fatty acid profile of the breast muscle of squabs from two meat pigeon breeds were determined. Breed-specific differences were detected in fat-related traits of intramuscular fat content and fatty acid composition. RNA-Sequencing was applied to compare the transcriptomes of muscle and liver tissues between squabs of two breeds to identify candidate genes associated with the differences in the capacity of fat deposition. A total of 27 differentially expressed genes assigned to pathways of lipid metabolism were identified, of which, six genes belonged to the peroxisome proliferator-activated receptor signaling pathway along with four other genes. Our results confirmed in part previous reports in livestock and provided also a number of genes which had not been related to fat deposition so far. These genes can serve as a basis for further investigations to screen markers closely associated with intramuscular fat content and fatty acid composition in squabs. The data from this study were deposited in the National Center for Biotechnology Information (NCBI)’s Sequence Read Archive under the accession numbers SRX1680021 and SRX1680022. This is the first transcriptome analysis of the muscle and liver tissue in Columba using next generation sequencing technology. Data provided here are of potential value to dissect functional genes influencing fat deposition in squabs. PMID:27175015

Model for turbidite-to-contourite continuum and multiple process transport in deep marine settings: examples in the rock record

NASA Astrophysics Data System (ADS)

Stanley, Daniel Jean

1993-01-01

Petrological analysis of geological sections in St. Croix in the Caribbean, the Niesenflysch in Switzerland and the Annot Sandstone in the French Maritime Alps sheds light on multiple process transport in deep marine settings. A model depicting a turbidite-to-contourite continuum of stratal types is applied to these three rock units. Recognition of a diverse suite of bedforms, coupled with analysis of paleocurrents, helps to better interpret depositional origin and basin paleogeography. The St. Croix strata record emplacement by gravity flows and, subsequently, by bottom currents flowing parallel to the base of slope; these sediments accumulated on a lower slope apron. A Niesenflysch section in the Swiss Alps west of Adelboden includes turbidites which were deposited at fairly regular intervals beyond the base of slope, in a setting more distal than that of the St. Croix sequences. Most of these turbidites appear to have been partially reworked by bottom currents related to basin circulation or to density flows from the basin margins. In the Annot Sandstone, reworked turbidites (termed transitional variants) and packets of entirely rippled strata are observed in submarine fan and slope sequences in the Peira-Cava area. In contrast to those in St. Croix and the Niesenflysch, the current-emplaced deposits of the Annot Sandstone are directly associated with fan-valley deposits. Such rippled strata in channels are deposits of gravity flow origin which were subsequently reworked downslope by currents generated by successive gravity flows; they also occur on levees by overbank flow. Consideration of multiple process transport is of special help to interpret sections which are poorly exposed, or which can be examined in cores, or which are located in sequences that have been highly deformed structurally.

Serendipitous discovery of Wolbachia genomes in multiple Drosophila species.

PubMed

Salzberg, Steven L; Dunning Hotopp, Julie C; Delcher, Arthur L; Pop, Mihai; Smith, Douglas R; Eisen, Michael B; Nelson, William C

2005-01-01

The Trace Archive is a repository for the raw, unanalyzed data generated by large-scale genome sequencing projects. The existence of this data offers scientists the possibility of discovering additional genomic sequences beyond those originally sequenced. In particular, if the source DNA for a sequencing project came from a species that was colonized by another organism, then the project may yield substantial amounts of genomic DNA, including near-complete genomes, from the symbiotic or parasitic organism. By searching the publicly available repository of DNA sequencing trace data, we discovered three new species of the bacterial endosymbiont Wolbachia pipientis in three different species of fruit fly: Drosophila ananassae, D. simulans, and D. mojavensis. We extracted all sequences with partial matches to a previously sequenced Wolbachia strain and assembled those sequences using customized software. For one of the three new species, the data recovered were sufficient to produce an assembly that covers more than 95% of the genome; for a second species the data produce the equivalent of a 'light shotgun' sampling of the genome, covering an estimated 75-80% of the genome; and for the third species the data cover approximately 6-7% of the genome. The results of this study reveal an unexpected benefit of depositing raw data in a central genome sequence repository: new species can be discovered within this data. The differences between these three new Wolbachia genomes and the previously sequenced strain revealed numerous rearrangements and insertions within each lineage and hundreds of novel genes. The three new genomes, with annotation, have been deposited in GenBank.

Shallowing-upward cyclic patterns within larger-scale transgressive-regressive (T-R) sedimentary sequences, St. Peter through Decorah Formations, Ordovician, Iowa area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Witzke, B.J.

1993-03-01

Four large-scale (2--8 Ma) T-R sedimentary sequences of M. Ord. age (late Chaz.-Sherm.) were delimited by Witzke Kolata (1980) in the Iowa area, each bounded by local to regional unconformity/disconformity surfaces. These encompass both siliciclastic and carbonate intervals, in ascending order: (1) St. Peter-Glenwood fms., (2) Platteville Fm., (3) Decorah Fm., (4) Dunleith/upper Decorah fms. Finer-scale resolution of depth-related depositional features has led to regional recognition of smaller-scale shallowing-upward cyclicity contained within each large-scale sequence. Such smaller-scale cyclicity encompasses stratigraphic intervals of 1--10 m thickness, with estimated durations of 0.5--1.5 Ma. The St. Peter Sandst. has long been regarded asmore » a classic transgressive sheet sand. However, four discrete shallowing-upward packages characterize the St. Peter-Glenwood interval regionally (IA, MN, NB, KS), including western facies displaying coarsening-upward sandstone packages with condensed conodont-rich brown shale and phosphatic sediments in their lower part (local oolitic ironstone), commonly above pyritic hardgrounds. Regional continuity of small-scale cyclic patterns in M. Ord. strata of the Iowa area may suggest eustatic controls; this can be tested through inter-regional comparisons.« less

Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

PubMed Central

Itani, Ghida Nouhad; Smith, Colin Andrew

2016-01-01

Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species. PMID:26939571

DNA microdevice for electrochemical detection of Escherichia coli 0157:H7 molecular markers.

PubMed

Berganza, J; Olabarria, G; García, R; Verdoy, D; Rebollo, A; Arana, S

2007-04-15

An electrochemical DNA sensor based on the hybridization recognition of a single-stranded DNA (ssDNA) probe immobilized onto a gold electrode to its complementary ssDNA is presented. The DNA probe is bound on gold surface electrode by using self-assembled monolayer (SAM) technology. An optimized mixed SAM with a blocking molecule preventing the nonspecific adsorption on the electrode surface has been prepared. In this paper, a DNA biosensor is designed by means of the immobilization of a single stranded DNA probe on an electrochemical transducer surface to recognize specifically Escherichia coli (E. coli) 0157:H7 complementary target DNA sequence via cyclic voltammetry experiments. The 21 mer DNA probe including a C6 alkanethiol group at the 5' phosphate end has been synthesized to form the SAM onto the gold surface through the gold sulfur bond. The goal of this paper has been to design, characterise and optimise an electrochemical DNA sensor. In order to investigate the oligonucleotide probe immobilization and the hybridization detection, experiments with different concentration of DNA and mismatch sequences have been performed. This microdevice has demonstrated the suitability of oligonucleotide Self-assembled monolayers (SAMs) on gold as immobilization method. The DNA probes deposited on gold surface have been functional and able to detect changes in bases sequence in a 21-mer oligonucleotide.

Dust Rains Deliver Diverse Assemblages of Microorganisms to the Eastern Mediterranean

NASA Astrophysics Data System (ADS)

Itani, Ghida Nouhad; Smith, Colin Andrew

2016-03-01

Dust rains may be particularly effective at delivering microorganisms, yet their biodiversities have been seldom examined. During 2011 and 2012 in Beirut, Lebanon, 16 of 21 collected rainfalls appeared dusty. Trajectory modelling of air mass origins was consistent with North African sources and at least one Southwest Asian source. As much as ~4 g particulate matter, ~20 μg DNA, and 50 million colony forming units were found deposited per square meter during rainfalls each lasting less than one day. Sequencing of 93 bacteria and 25 fungi cultured from rain samples revealed diverse bacterial phyla, both Gram positive and negative, and Ascomycota fungi. Denaturing Gradient Gel Electrophoresis of amplified 16S rDNA of 13 rains revealed distinct and diverse assemblages of bacteria. Dust rain 16S libraries yielded 131 sequences matching, in decreasing order of abundance, Betaproteobacteria, Alphaproteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, Cyanobacteria, Epsilonproteobacteria, Gammaproteobacteria, and Deltaproteobacteria. Clean rain 16S libraries yielded 33 sequences matching only Betaproteobacteria family Oxalobacteraceae. Microbial composition varied between dust rains, and more diverse and different microbes were found in dust rains than clean rains. These results show that dust rains deliver diverse communities of microorganisms that may be complex products of revived desert soil species and fertilized cloud species.

Valles Marineris Basin Beds: a Complex Story

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1985-01-01

High resolution stereoimages of the central Valles Marineris enabled detailed geologic mapping on Ophir and Candor Chasmata. Abundant light colored deposits, both layered and massive, fill the chasmata in this region. Units within these deposits were identified by their erosional characteristics and superposition and cross cutting relations. The Valles Marineris beds reflect a history of repeated faulting, volcanic eruptions, and deposition and erosion, resulting in stratigraphic sequences with several unconformities. Because of the preponderance of apparent volcanic deposits inside the troughs, the chasmata may not be simple grabens, but rather giant volcano tectonic depressions. Major events in chasmata development are examined.

A proposal to rename the hyperthermophile Pyrococcus woesei as Pyrococcus furiosus subsp. woesei.

PubMed

Kanoksilapatham, Wirojne; González, Juan M; Maeder, Dennis L; DiRuggiero, Jocelyne; Robb, Frank T

2004-10-01

Pyrococcus species are hyperthermophilic members of the order Thermococcales, with optimal growth temperatures approaching 100 degrees C. All species grow heterotrophically and produce H2 or, in the presence of elemental sulfur (S(o)), H2S. Pyrococcus woesei and P. furiosus were isolated from marine sediments at the same Vulcano Island beach site and share many morphological and physiological characteristics. We report here that the rDNA operons of these strains have identical sequences, including their intergenic spacer regions and part of the 23S rRNA. Both species grow rapidly and produce H2 in the presence of 0.1% maltose and 10-100 microM sodium tungstate in S(o)-free medium. However, P. woesei shows more extensive autolysis than P. furiosus in the stationary phase. Pyrococcus furiosus and P. woesei share three closely related families of insertion sequences (ISs). A Southern blot performed with IS probes showed extensive colinearity between the genomes of P. woesei and P. furiosus. Cloning and sequencing of ISs that were in different contexts in P. woesei and P. furiosus revealed that the napA gene in P. woesei is disrupted by a type III IS element, whereas in P. furiosus, this gene is intact. A type I IS element, closely linked to the napA gene, was observed in the same context in both P. furiosus and P. woesei genomes. Our results suggest that the IS elements are implicated in genomic rearrangements and reshuffling in these closely related strains. We propose to rename P. woesei a subspecies of P. furiosus based on their identical rDNA operon sequences, many common IS elements that are shared genomic markers, and the observation that all P. woesei nucleotide sequences deposited in GenBank to date are > 99% identical to P. furiosus sequences.

The basal fallout and surge deposits of the mafic ignimbrite-forming Villa Senni Eruption Unit, (Colli Albani volcano, Italy)

NASA Astrophysics Data System (ADS)

Vinkler, A.; Ort, M. H.; Giordano, G.

2009-12-01

The Villa Senni Eruption Unit (350ka) represents the youngest large caldera-forming eruption of the Colli Albani volcano near Rome (Italy). The Colli Albani magma is marked by very undersaturated chemistry (tephritic to K-foiditic) and low viscosity. The total volume of the Villa Senni Eruption Unit is estimated at > 50 km3 and 30 km3 DRE (Watkins et al., 2002). The unit includes a sequence of a basal fallout/surge deposit, two main ignimbrites emplaced during the same eruptive event, a series of breccia deposits positioned between the two ignimbrites, and a rarely preserved final fallout. The basal surge and fallout sequence may help answer questions regarding the beginning of a large mafic ignimbrite eruption. The entire surge and fallout deposit is 190 cm thick at the caldera wall, consisting of 19 individual, parallel to faintly cross-stratified layers. The deposit distally thins to 25 cm at 18 km east of the caldera and to 2.5 cm at 21 km NW of the caldera. The eruption started with fine ash surges showing cross-stratification at proximal locations and being vesicular distally. The deposit consists mainly of juvenile clasts, which are angular, poorly vesicular, and rich in leucite microlites (~80 µm). Clasts around 100-150 μm show signs of magma-water interaction: quench fracturing: conchoidal and step fractures, smooth surfaces, adhering clasts and melt film. These features are present in several thin alternating surge and fall sequences at the base of the deposit. The lithic clasts in these first deposits are concentrated in layers, indicating pulsatory behavior of the eruption. Upward, the deposit consists of thicker, coarse ash to lapilli fallout layers from more sustained columns. The juvenile clasts in these deposits are more irregular, with higher vesicularity (but less than 50%) and smaller leucite microlites (~60 μm). The uppermost part of the basal fallout/surge deposit shows features transitional to the first large ignimbrite: fallout deposits alternate with poorly sorted flow units, with an increase in free leucite crystals and lithic content, with more abundant deep lithic clasts and a further leucite microlite size decrease (~20 μm) , which could indicate an accelerating magma in the conduit. We think that external factors, such as magma-water interaction and consequent gas explosions, triggered the highly explosive Villa Senni Eruption. Low vesicularity of the early juvenile clasts suggests the magma was relatively low in volatiles at the outset and did not start as a gas-driven eruption. Later in the eruption, the high ascent rate and fast decompression of the magma sustained a large explosive eruption.

Impact wave deposits provide new constraints on the location of the K/T boundary impact

NASA Technical Reports Server (NTRS)

Hildebrand, A. R.; Boynton, W. V.

1988-01-01

All available evidence is consistent with an impact into oceanic crust terminating the Cretaceous Period. Although much of this evidence is incompatible with an endogenic origin, some investigators still feel that a volcanic origin is possible for the Cretaceous/Tertiary (K/T) boundary clay layers. The commonly cited evidence for a large impact stems from delicate clay layers and their components and the impact site has not yet been found. Impact sites have been suggested all over the globe. The impact is felt to have occurred near North America by: the occurrence of a 2 cm thick ejecta layer only at North American locales, the global variation of shocked quartz grain sizes peaking in North America, the global variation of spinel compositions with most refractory compositions occurring in samples from the Pacific region and possibly uniquely severe plant extinctions in the North American region. The K/T boundary interval was investigated as preserved on the banks of the Brazos River, Texas. The K/T fireball and ejecta layers with associated geochemical anomalies were found interbedded with this sequence which apparently allows a temporal resolution 4 orders of magnitude greater than typical K/T boundary sections. A literature search reveals that such coarse deposits are widely preserved at the K/T boundary. Impact wave deposits have not been found elsewhere on the globe, suggesting the impact occurred between North and South America. The coarse deposits preserved in Deep Sea Drilling Project (DSDP) holes 151-3 suggest the impact occurred nearby. Subsequent tectonism has complicated the picture.

Calibration of high frequency pollen sequences and tree-ring records

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wigand, P.E.; Rose, M.R.

This paper examines two radiocarbon dated paleoenvironmental records from southern Nevada for the possibility of correlating high-frequency pollen samples with nearby long-term tree-ring sequences. Variable deposition rate are discussed. Radiocarbon dating control of the pollen cores, as well as closer interval sampling is presented.

Event sand layers suggesting the possibility of tsunami deposits identified in the upper Holocene sequence nearby the Kuwana fault, central Japan

NASA Astrophysics Data System (ADS)

Niwa, Y.; Sugai, T.; Matsuzaki, H.

2012-12-01

The Kuwana fault is located on coastal area situated on inner part of the Ise Bay, central Japan, which opens to the Nankai Trough. This reverse fault displaces a late Pleistocene terrace surface with 1 to 2 mm/yr of average vertical slip rate, and a topset of delta at several meters, respectively. And, this fault is estimated to have generated two historical earthquakes (the AD 745 Tempyo and the AD 1586 Tensho earthquakes). We identified two event sand layers from upper Holocene sequence on the upthrown side of the Kuwana fault. Upper Holocene deposits in this study area show prograding delta sequence; prodelta mud, delta front sandy silt to sand, and flood plain sand/mud, respectively, from lower to upper. Two sand layers intervene in delta front sandy silt layer, respectively. Lower sand layer (S1) shows upward-coarsening succession, whereas upper sand layer (S2) upward-fining succession. These sand layers contain sharp contact, rip-up crust, and shell fragment, indicating strong stream flow. Radiocarbon ages show that these strong stream flow events occurred between 3000 and 1600 years ago. Decreasing of salinity is estimated from decreasing trend of electrical conductivity (EC) across S1. Based on the possibility that decreasing of salinity can be occurred by shallowing of water depth caused by coseismic uplift, and that S1 can be correlated with previously known faulting event on the Kuwana fault, S1 is considered to be tsunami deposits caused by faulting on the Kuwana fault. On the other hand, S2, which cannot be correlated with previously known faulting events on the Kuwana fault, may be tsunami deposits by ocean-trench earthquake or storm deposits. In the presentation, we will discuss more detail correlation of these sand deposits not only in the upthrown side of the Kuwana fault, but also downthrown side of the fault.

Unifying tephrostratigraphic approaches to redefine major Holocene marker tephras, Mt. Taranaki, New Zealand

NASA Astrophysics Data System (ADS)

Damaschke, M.; Cronin, S. J.; Torres-Orozco, R.; Wallace, R. C.

2017-05-01

In this study, geochemical fingerprinting of glass shards and titanomagnetite phenocrysts was used to match twenty complex pyroclastic deposits from the flanks of Mt. Taranaki to major tephra fall ;marker beds; in medial and distal deposition sites. These correlations hinged upon identifying time-bound compositional changes (a chemostratigraphy) in distal Taranaki tephra-fall sequences preserved in lake and peat sediment records around the volcano. The current work shows that previous soil-stratigraphy based studies led to miscorrelations, because they relied upon radiocarbon dates, a ;counting back; approach, and an underestimate of the number of eruptions that actually occurred in any time frame. The new tephrostratigraphy proposed at Mt. Taranaki resulted from stratigraphic rearranging of several earlier-defined units. Some tephra units are older than previously determined (e.g., Waipuku, Tariki, and Mangatoki; 6 to 9 cal ka BP), while one of the most prominent Taranaki marker tephra deposit, the Korito, is shown to lie stratigraphically above a widespread rhyolitic marker bed from Taupo volcano, the Stent Tephra (also known as unit Q; 4.3 cal ka BP). Pyroclastic tephra deposits previously dated between 6 to 4 cal ka BP at a key tephra section, c. 40 km NE of Mt. Taranaki's summit, were misidentified and are now shown to comprise new marker tephra deposits, including the Kokowai ( 4.7 cal ka BP), which is a prominent marker horizon on the eastern flanks of the volcano. A new local proximal stratigraphy for < 5 cal ka BP tephra units can be well correlated to tephra layers within distal lake and peat sequences, but the differences between the two records indicates an overall larger number of eruptions have occurred at this volcano than previously thought. This study additionally demonstrates the utility of titanomagnetite chemistry for discrimination and correlation of groups or sequences of tephra deposits - even if unique compositions cannot be identified.

The dating and interpretation of a Mode 1 site in the Luangwa Valley, Zambia.

PubMed

Barham, Lawrence; Phillips, William M; Maher, Barbara A; Karloukovski, Vassil; Duller, Geoff A T; Jain, Mayank; Wintle, Ann G

2011-05-01

Flake based assemblages (Mode 1) comprise the earliest stone technologies known, with well-dated Oldowan sites occurring in eastern Africa between ~2.6-1.7 Ma, and in less securely dated contexts in central, southern and northern Africa. Our understanding of the spread and local development of this technology outside East Africa remains hampered by the lack of reliable numerical dating techniques applicable to non-volcanic deposits. This study applied the still relatively new technique of cosmogenic nuclide burial dating ((10)Be/(26)Al) to calculate burial ages for fluvial gravels containing Mode 1 artefacts in the Luangwa Valley, Zambia. The Manzi River, a tributary of the Luangwa River, has exposed a 4.7 m deep section of fluvial sands with discontinuous but stratified gravel layers bearing Mode 1, possibly Oldowan, artefacts in the basal layers. An unconformity divides the Manzi section, separating Mode 1 deposits from overlying gravels containing Mode 3 (Middle Stone Age) artefacts. No diagnostic Mode 2 (Acheulean) artefacts were found. Cosmogenic nuclide burial dating was attempted for the basal gravels as well as exposure ages for the upper Mode 3 gravels, but was unsuccessful. The complex depositional history of the site prevented the calculation of reliable age models. A relative chronology for the full Manzi sequence was constructed, however, from the magnetostratigraphy of the deposit (N>R>N sequence). Isothermal thermoluminescence (ITL) dating of the upper Mode 3 layers also provided consistent results (~78 ka). A coarse but chronologically coherent sequence now exists for the Manzi section with the unconformity separating probable mid- or early Pleistocene deposits below from late Pleistocene deposits above. The results suggest Mode 1 technology in the Luangwa Valley may post-date the Oldowan in eastern and southern Africa. The dating programme has contributed to a clearer understanding of the geomorphological processes that have shaped the valley and structured its archaeological record. Copyright © 2010 Elsevier Ltd. All rights reserved.

Seep carbonates and chemosynthetic coral communities in the Early Paleocene alpine accretionary wedge: evidences from the Bocco Shale (Internal Liguride ophiolitic sequence, Northern Apennine, Italy)

NASA Astrophysics Data System (ADS)

Pandolfi, Luca; Boschi, Chiara; Luvisi, Edoardo; Alessandro, Ellero; Marroni, Michele; Meneghini, Francesca

2014-05-01

In Northern Apennines, the Internal Liguride units are characterized by an ophiolite sequence that represents the stratigraphic base of a Late Jurassic-Early Paleocene sedimentary cover. The Bocco Shale represents the youngest deposit recognized in the sedimentary cover of the ophiolite sequence, sedimented just before the inception of subduction-related deformation history. The Bocco Shale has been interpreted as a fossil example of deposits related to the frontal tectonic erosion of the alpine accretionary wedge slope. The frontal tectonic erosion resulted in a large removal of material from the accretionary wedge front reworked as debris flows and slide deposits sedimented on the lower plate above the trench deposits. These trench-slope deposits may have been successively deformed and metamorphosed during the following accretion processes. The frontal tectonic erosion can be envisaged as a common process during the convergence-related evolution of the Ligure-Piemontese oceanic basin in the Late Cretaceous-Early Tertiary time span. In the uppermost Internal Liguride tectonic unit (Portello Unit of Pandolfi and Marroni. 1997), that crops-out in Trebbia Valley, several isolated blocks of authigenic carbonates, unidentificated corals and intrabasinal carbonatic arenites have been recognized inside the fine-grained sediments that dominate the Early Paleocene Lavagnola Fm. (cfr. Bocco Shale Auctt.). The preliminary data on stable isotopes from blocks of authigenic carbonates (up to 1 m thick and 3 m across) and associated corals archive a methane signatures in their depleted carbon isotope pattern (up to δ13C -30‰ PDB) and suggest the presence of chemosynthetic paleocommunities. The seep-carbonates recognized at the top of Internal Liguride succession (cfr. Bocco Shale Auctt.) occur predominantly as blocks in very thick mudstone-dominated deposits and probably developed in an environment dominated by the expulsion of large volume of cold methane-bearing fluids focused in the frontal part of the Early Paleocene alpine accretionary wedge.

Coastal evidence for Holocene subduction-zone earthquakes and tsunamis in central Chile

USGS Publications Warehouse

Dure, Tina; Cisternas, Marco; Horton, Benjamin; Ely, Lisa; Nelson, Alan R.; Wesson, Robert L.; Pilarczyk, Jessica

2015-01-01

The ∼500-year historical record of seismicity along the central Chile coast (30–34°S) is characterized by a series of ∼M 8.0–8.5 earthquakes followed by low tsunamis (<4 m) occurring on the megathrust about every 80 years. One exception is the AD 1730 great earthquake (M 9.0–9.5) and high tsunami (>10 m), but the frequency of such large events is unknown. We extend the seismic history of central Chile through a study of a lowland stratigraphic sequence along the metropolitan coast north of Valparaíso (33°S). At this site, higher relative sea level during the mid Holocene created a tidal marsh and the accommodation space necessary for sediment that preserves earthquake and tsunami evidence. Within this 2600-yr-long sequence, we traced six laterally continuous sand beds probably deposited by high tsunamis. Plant remains that underlie the sand beds were radiocarbon dated to 6200, 5600, 5000, 4400, 3800, and 3700 cal yr BP. Sediment properties and diatom assemblages of the sand beds—for example, anomalous marine planktonic diatoms and upward fining of silt-sized diatom valves—point to a marine sediment source and high-energy deposition. Grain-size analysis shows a strong similarity between inferred tsunami deposits and modern coastal sediment. Upward fining sequences characteristic of suspension deposition are present in five of the six sand beds. Despite the lack of significant lithologic changes between the sedimentary units under- and overlying tsunami deposits, we infer that the increase in freshwater siliceous microfossils in overlying units records coseismic uplift concurrent with the deposition of five of the sand beds. During our mid-Holocene window of evidence preservation, the mean recurrence interval of earthquakes and tsunamis is ∼500 years. Our findings imply that the frequency of historical earthquakes in central Chile is not representative of the greatest earthquakes and tsunamis that the central Chilean subduction zone has produced.

Sedimentology and Sedimentary Dynamics of the Desmoinesian Cherokee Group, Deep Anadarko Basin, Texas Panhandle

NASA Astrophysics Data System (ADS)

Hu, N.; Loucks, R.; Frebourg, G.

2015-12-01

Understanding the spatial variability of deep-water facies is critical to deep-water research because of its revealing information about the relationship between desity flow processes and their resultant sedimentary sequences. The Cherokee Group in the Anadarko Basin, northeastern Texas Panhandle, provides an opportunity to investigate an icehouse-greenhouse Pennsylvanian hybrid system that well demonstrates the intricacies of vertical and lateral facies relationships in an unconfined fan-delta fed deep-water slope to basinal setting. The stratigraphic section ranges in thickness from 150 to 460 m. The cyclic sedimentation and foreland basin tectonics resulted in a complex stratal architecture that was sourced by multiple areas of sediment input. This investigation consists of wireline-log and core data. Five-thousand wireline logs were correlated in an area of over 9500 sq km to map out six depositional sequences that are separated by major flooding events. These events are correlative over the whole area of study. Six cores, that sample nearly the complete section, were described for lithofacies. Lithofacies are recognized based on depositional features and mineralogy:(1) Subarkose, (2) Lithicarkoses, (3) Sandy siliciclastic conglomerate, (4) Muddy calcareous conglomerate, (5) Crinoidal packstone, (6) Oodic grainstone, (7)Pelodic grainstone, (8) Ripple laminated mudrock, (9) faint laminated mudrock. The integration of isopachs of depositional sequences with the lithofacies has allowed the delineation of the spatial and temporal evolution of the slope to basin-floor system. Thin-to-thick bedded turbidites, hyperconcentrated density flow deposits (slurry beds), and debris and mud flow deposits were observed and can be used to better predicte lithofacies distributions in areas that have less data control. These mixed siliciclastic and carbonate deposits can be carrier beds for the hydrocarbons generated from the enclosing organic-rich (TOC ranges from 0.55 to 6.77wt%), dysareobic to anaerobic mudstones.

Inversion Recovery Ultrashort Echo Time Magnetic Resonance Imaging: A Method for Simultaneous Direct Detection of Myelin and High Signal Demonstration of Iron Deposition in the Brain – A Feasibility Study

PubMed Central

Sheth, Vipul R.; Fan, Shujuan; He, Qun; Ma, Yajun; Annesse, Jacopo; Switzer, Robert; Corey-Bloom, Jody; Bydder, Graeme M; Du, Jiang

2017-01-01

Multiple sclerosis (MS)causes demyelinating lesions in the white matter and increased iron deposition in the subcortical gray matter. Myelin protons have an extremely short T2* (less than 1 ms) and are not directly detected with conventional clinical magnetic resonance (MR) imaging sequences. Iron deposition also reduces T2*, leading to reduced signal on clinical sequences. In this study we tested the hypothesis that the inversion recovery ultrashort echo time (IR-UTE) pulse sequence can directly and simultaneously image myelin and iron deposition using a clinical 3T scanner. The technique was first validated on a synthetic myelinphantom (myelin powder in D2O) and a Feridex iron phantom. This was followed by studies of cadaveric MS specimens, healthy volunteers and MS patients. UTE imaging of the synthetic myelin phantom showed an excellent bi-component signal decay with two populations of protons, one with a T2* of 1.2 ms (residual water protons) and the other with a T2* of 290 μs (myelin protons). IR-UTE imaging shows sensitivity to a wide range of iron concentrations from 0.5 to ∼30 mM. The IR-UTE signal from white matter of the brain of healthy volunteers shows a rapid signal decay with a short T2* of ∼300 μs, consistent with the T2* values of myelin protons in the synthetic myelin phantom. IR-UTE imaging in MS brain specimens and patients showed multiple white matter lesions as well as areas of high signal in subcortical gray matter. This in specimens corresponded in position to Perl's diaminobenzide staining results, consistent with increased iron deposition. IR-UTE imaging simultaneously detects lesions with myelin loss in the white matter and iron deposition in the gray matter. PMID:28038965

The dating and interpretation of a Mode 1 site in the Luangwa Valley, Zambia

USGS Publications Warehouse

Barham, L.; Phillips, W.M.; Maher, B.A.; Karloukovski, V.; Duller, G.A.T.; Jain, M.; Wintle, A.G.

2011-01-01

Flake based assemblages (Mode 1) comprise the earliest stone technologies known, with well-dated Oldowan sites occurring in eastern Africa between ??? 2.6-1.7 Ma, and in less securely dated contexts in central, southern and northern Africa. Our understanding of the spread and local development of this technology outside East Africa remains hampered by the lack of reliable numerical dating techniques applicable to non-volcanic deposits. This study applied the still relatively new technique of cosmogenic nuclide burial dating (10Be/26Al) to calculate burial ages for fluvial gravels containing Mode 1 artefacts in the Luangwa Valley, Zambia. The Manzi River, a tributary of the Luangwa River, has exposed a 4.7 m deep section of fluvial sands with discontinuous but stratified gravel layers bearing Mode 1, possibly Oldowan, artefacts in the basal layers. An unconformity divides the Manzi section, separating Mode 1 deposits from overlying gravels containing Mode 3 (Middle Stone Age) artefacts. No diagnostic Mode 2 (Acheulean) artefacts were found. Cosmogenic nuclide burial dating was attempted for the basal gravels as well as exposure ages for the upper Mode 3 gravels, but was unsuccessful. The complex depositional history of the site prevented the calculation of reliable age models. A relative chronology for the full Manzi sequence was constructed, however, from the magnetostratigraphy of the deposit (N>R>N sequence). Isothermal thermoluminescence (ITL) dating of the upper Mode 3 layers also provided consistent results (???78 ka). A coarse but chronologically coherent sequence now exists for the Manzi section with the unconformity separating probable mid- or early Pleistocene deposits below from late Pleistocene deposits above. The results suggest Mode 1 technology in the Luangwa Valley may post-date the Oldowan in eastern and southern Africa. The dating programme has contributed to a clearer understanding of the geomorphological processes that have shaped the valley and structured its archaeological record. ?? 2010 Elsevier Ltd.

Sedimentation and basin-fill history of the Neogene clastic succession exposed in the southeastern fold belt of the Bengal Basin, Bangladesh: a high-resolution sequence stratigraphic approach

NASA Astrophysics Data System (ADS)

Royhan Gani, M.; Mustafa Alam, M.

2003-02-01

The Tertiary basin-fill history of the Bengal Basin suffers from oversimplification. The interpretation of the sedimentary history of the basin should be consistent with the evolution of its three geo-tectonic provinces, namely, western, northeastern and eastern. Each province has its own basin generation and sediment-fill history related mainly to the Indo-Burmese and subordinately to the Indo-Tibetan plate convergence. This paper is mainly concerned with facies and facies sequence analysis of the Neogene clastic succession within the subduction-related active margin setting (oblique convergence) in the southeastern fold belt of the Bengal Basin. Detailed fieldwork was carried out in the Sitapahar anticline of the Rangamati area and the Mirinja anticline of the Lama area. The study shows that the exposed Neogene succession represents an overall basinward progradation from deep marine through shallow marine to continental-fluvial environments. Based on regionally correlatable erosion surfaces the entire succession (3000+ m thick) has been grouped into three composite sequences C, B and A, from oldest to youngest. Composite sequence C begins with deep-water base-of-slope clastics overlain by thick slope mud that passes upward into shallow marine and nearshore clastics. Composite sequence B characteristically depicts tide-dominated open-marine to coastal depositional systems with evidence of cyclic marine regression and transgression. Repetitive occurrence of incised channel, tidal inlet, tidal ridge/shoal, tidal flat and other tidal deposits is separated by shelfal mudstone. Most of the sandbodies contain a full spectrum of tide-generated structures (e.g. herringbone cross-bedding, bundle structure, mud couplet, bipolar cross-lamination with reactivation surfaces, 'tidal' bedding). Storm activities appear to have played a subordinate role in the mid and inner shelf region. Rizocorallium, Rosselia, Planolites and Zoophycos are the dominant ichnofacies within the shelfal mudstone. This paralic sedimentation of Neogene succession in the study area can serve as a good point of reference for tide-dominated regressive shelf depositional systems. The top of the composite sequence B is marked by a pronounced erosion surface indicating the final phase of marine regression followed by the gradual establishment of continental-fluvial depositional systems represented by composite sequence A. In this composite sequence, stacked channel bars of low-sinuosity braided rivers gradually pass upsequence into high-sinuosity meandering river deposits. A sequence stratigraphic approach has been adopted to interpret the basin-fill history with respect to relative sea-level changes; and to subdivide the rock record into several sequences and units (systems tracts and parasequences) based on identified bounding discontinuities, such as transgressive erosion surface (TES), regressive erosion surface (RES), marine flooding surface (MFS), and incised valley floor (IVF). This approach provides new insight for both exploration and exploitation strategy for hydrocarbon plays that may prove vital to the oil companies engaged in exploration activities in the Bengal Basin. It is strongly recommended here that the traditional lithostratigraphic classification of this part of the basin, which is based on the Assam stratigraphy, be abandoned or at least revised. A tentative allostratigraphic scheme is presented, and it is suggested that to formalize the scheme further study, both surface and subsurface, is needed.

Paleocene coal deposits of the Wilcox group, central Texas

USGS Publications Warehouse

Hook, Robert W.; Warwick, Peter D.; SanFilipo, John R.; Schultz, Adam C.; Nichols, Douglas J.; Swanson, Sharon M.; Warwick, Peter D.; Karlsen, Alexander K.; Merrill, Matthew D.; Valentine, Brett J.

2011-01-01

Coal deposits in the Wilcox Group of central Texas have been regarded as the richest coal resources in the Gulf Coastal Plain. Although minable coal beds appear to be less numerous and generally higher in sulfur content (1 percent average, as-received basis; table 1) than Wilcox coal deposits in the Northeast Texas and Louisiana Sabine assessment areas (0.5 and 0.6 percent sulfur, respectively; table 1), net coal thickness in coal zones in central Texas is up to 32 ft thick and more persistent along strike (up to 15 mi) at or near the surface than coals of any other Gulf Coast assessment area. The rank of the coal beds in central Texas is generally lignite (table 1), but some coal ranks as great as subbituminous C have been reported (Mukhopadhyay, 1989). The outcrop of the Wilcox Group in central Texas strikes northeast, extends for approximately 140 mi between the Trinity and Colorado Rivers, and covers parts of Bastrop, Falls, Freestone, Lee, Leon, Limestone, Milam, Navarro, Robertson, and Williamson Counties (Figure 1). Three formations, in ascending order, the Hooper, Simsboro, and Calvert Bluff, are recognized in central Texas (Figure 2). The Wilcox Group is underlain conformably by the Midway Group, a mudstone-dominated marine sequence, and is overlain and scoured locally by the Carrizo Sand, a fluvial unit at the base of the Claiborne Group.

Shallow Methane Hydrates: Rates, Mechanisms of Formation and Environmental Significance.

NASA Astrophysics Data System (ADS)

Torres, M. E.; Trehu, A. M.

2005-05-01

Shallow gas hydrates have been identified at more than 20 locations worldwide, and are commonly associated with observations of bubble discharge at the seafloor. These deposits are host to active chemosynthetic communities and are likely to play a predominant role in energy, climate and carbon cycle issues associated with hydrate processes. Because seafloor gas hydrates are not in equilibrium with seawater, these deposits require a constant supply of methane to replace loss by continuous diffusion to bottom water. We will summarize evidence documenting that at the shallow deposits on Hydrate Ridge (OR) methane must be delivered in the free gas phase and present simple models used to infer formation rates, which are orders of magnitude higher than those for hydrates formed deeper in the sediment column (Torres et al., 2004). At Hydrate Ridge, methane gas is channeled from deep accretionary margin sequences to the gas hydrate stability zone (GHSZ) through a permeable layer that has been mapped seismically (Horizon A). High gas pressure in this horizon can drive gas through the GHSZ to the seafloor (Trehu et al., 2004). We will review current ideas that address mechanisms whereby gas migrates from Horizon A to the seafloor, including inhibition by capillary effects and the development of a high salinity front that can shift the hydrate stability field enough to allow for methane transport as a gas phase.

Controlling the formation and stability of ultra-thin nickel silicides - An alloying strategy for preventing agglomeration

NASA Astrophysics Data System (ADS)

Geenen, F. A.; van Stiphout, K.; Nanakoudis, A.; Bals, S.; Vantomme, A.; Jordan-Sweet, J.; Lavoie, C.; Detavernier, C.

2018-02-01

The electrical contact of the source and drain regions in state-of-the-art CMOS transistors is nowadays facilitated through NiSi, which is often alloyed with Pt in order to avoid morphological agglomeration of the silicide film. However, the solid-state reaction between as-deposited Ni and the Si substrate exhibits a peculiar change for as-deposited Ni films thinner than a critical thickness of tc = 5 nm. Whereas thicker films form polycrystalline NiSi upon annealing above 450 ° C , thinner films form epitaxial NiSi2 films that exhibit a high resistance toward agglomeration. For industrial applications, it is therefore of utmost importance to assess the critical thickness with high certainty and find novel methodologies to either increase or decrease its value, depending on the aimed silicide formation. This paper investigates Ni films between 0 and 15 nm initial thickness by use of "thickness gradients," which provide semi-continuous information on silicide formation and stability as a function of as-deposited layer thickness. The alloying of these Ni layers with 10% Al, Co, Ge, Pd, or Pt renders a significant change in the phase sequence as a function of thickness and dependent on the alloying element. The addition of these ternary impurities therefore changes the critical thickness tc. The results are discussed in the framework of classical nucleation theory.

Economic geology of the Zipaquira quadrangle and adjoining area, Department of Cundinamarca, Colombia

USGS Publications Warehouse

McLaughlin, Donald H.; Arce Herrera, Marino

1970-01-01

At least four evaporite sequences are interbedded with Cretaceous strata in the Bogotga area of the Cordillera Oriental of Colombia. The easternmost and oldest evaporite interval is of probable Berriasian-Valanglnian age; the next oldest is of probable late Barremian-early Aptian age, and is followed by a possible late Aptian sequence. The westernmost and best known sequence is Turonian-early Coniacian in age, in the Sabana de Bogota. This youngest sequence contains the thickest known salt deposits and is probably the most widespread geographically. Three gypsum deposits of probable Barremian-Valanginian age are in the eastern part of the area under investigation. These deposits may have been leached from former salt accumulations. No other evaporites are exposed, but numerous brine springs are known, That the sources of these brines are neither deep not distant is suggested by the generally high concentrations, of the brines, the local presence of rute (leached salt residue), and the commonly significant amounts of H2S gas emitted at these springs. The rock salt exposed in three accessible mines commonly has a characteristic lamination caused by alternating layers of relatively pure halite and very argillaceous halite. Ubiquitously scattered throughout all salt deposits are small clasts of black, commonly pyritic, marly claystone. This lithology is also present as large claystone bodies conformably interbedded in the salt strata. Anhydrite is rare and is apparently more abundant at the Zipaquira mine that at the Nemocon and Upin mine. Paleontologic evidence in the Sabana de Bogota demonstrates that the salt-claystone series, hematite impregnated strata, and carbonaceous to locally coaly claystone are coeval. The salt-claystone facies may have been deposited in shallow evaporite pans that were separated within the overall evaporite interval by barriers on which the locally hematitic strata were deposited. The carbonaceous facies may also have formed in barrier areas or on the edges of the evaporite basins. Whether or not this facies relationship prevails in the older evaporite intervals is not known; meager evidence suggests that it does. Nonmetallic mineral resources other than the evaporite minerals are phosphate rock, limestone, kaolinite, and emeralds. Metallic mineral deposits present in the Zone include hematite at Pericos, La Caldera, Tibirita, Nueva Vizcaya, and Cerro de Montecristo; chalcopyrite at Cerro do Cobre and at Farallones de Medina; galena in several places along the Rio Farallones and Rio Gacheta; and spahlerite in the Junin district.

Two examples of subaqueously welded ash-flow tuffs: the Visean of southern Vosges (France) and the Upper Cretaceous of northern Anatolia (Turkey)

NASA Astrophysics Data System (ADS)

Schneider, Jean-Luc; Fourquin, Claude; Paicheler, Jean-Claude

1992-02-01

Pyroclastic deposits interpreted as subaqueous ash-flow tuff have been recognized within Archean to Recent marine and lacustrine sequences. Several authors proposed a high-temperature emplacement for some of these tuffs. However, the subaqueous welding of pyroclastic deposits remains controversial. The Visean marine volcaniclastic formations of southern Vosges (France) contain several layers of rhyolitic and rhyodacitic ash-flow tuff. These deposits include, from proximal to distal settings, breccia, lapilli and fine-ash tuff. The breccia and lapilli tuff are partly welded, as indicated by the presence of fiamme, fluidal and axiolitic structures. The lapilli tuff form idealized sections with a lower, coarse and welded unit and an upper, bedded and unwelded fine-ash tuff. Sedimentary structures suggest that the fine-ash tuff units were deposited by turbidity currents. Welded breccias, interbedded in a thick submarine volcanic complex, indicate the close proximity of the volcanic source. The lapilli and fine-ash tuff are interbedded in a thick marine sequence composed of alternating sandstones and shales. Presence of a marine stenohaline fauna and sedimentary structures attest to a marine depositional environment below storm-wave base. In northern Anatolia, thick massive sequences of rhyodacitic crystal tuff are interbedded with the Upper Cretaceous marine turbidites of the Mudurnu basin. Some of these tuffs are welded. As in southern Vosges, partial welding is attested by the presence of fiamme and fluidal structures. The latter are frequent in the fresh vitric matrix. These tuff units contain a high proportion of vitroclasis, and were emplaced by ash flows. Welded tuff units are associated with non-welded crystal tuff, and contain abundant bioclasts which indicate mixing with water during flowage. At the base, basaltic breccia beds are associated with micritic beds containing a marine fauna. The welded and non-welded tuff sequences are interbedded in an alternation of limestones and marls. These limestones are rich in pelagic microfossils. The evidence above strongly suggest that in both examples, tuff beds are partly welded and were emplaced at high temperature by subaqueous ash flows in a permanent marine environment. The sources of the pyroclastic material are unknown in both cases. We propose that the ash flows were produced during submarine fissure eruptions. Such eruptions could produce non-turbulent flows which were insulated by a steam carapace before deposition and welding. The welded ash-flow tuff deposits of southern Vosges and northern Anatolia give strong evidence for existence of subaqueous welding.

Whole-genome sequence of Clostridium lituseburense L74, isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus.

PubMed

Lee, Yookyung; Lim, Sooyeon; Rhee, Moon-Soo; Chang, Dong-Ho; Kim, Byoung-Chan

2016-03-01

Clostridium lituseburense L74 was isolated from the larval gut of the rhinoceros beetle, Trypoxylus dichotomus collected in Yeong-dong, Chuncheongbuk-do, South Korea and subjected to whole genome sequencing on HiSeq platform and annotated on RAST. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession NZ_LITJ00000000.

Complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from lettuce (Lactuca sativa) originating from a conventional field in Norway.

PubMed

Dees, Merete Wiken; Brurberg, May Bente; Lysøe, Erik

2016-12-01

Here, we present the 3,795,952 bp complete genome sequence of the biofilm-forming Curtobacterium sp. strain BH-2-1-1, isolated from conventionally grown lettuce ( Lactuca sativa ) from a field in Vestfold, Norway. The nucleotide sequence of this genome was deposited into NCBI GenBank under the accession CP017580.

Immunoglobulin Light Chains Form an Extensive and Highly Ordered Fibril Involving the N- and C-Termini

PubMed Central

2017-01-01

Light-chain (AL)-associated amyloidosis is a systemic disorder involving the formation and deposition of immunoglobulin AL fibrils in various bodily organs. One severe instance of AL disease is exhibited by the patient-derived variable domain (VL) of the light chain AL-09, a 108 amino acid residue protein containing seven mutations relative to the corresponding germline protein, κI O18/O8 VL. Previous work has demonstrated that the thermodynamic stability of native AL-09 VL is greatly lowered by two of these mutations, Y87H and N34I, whereas a third mutation, K42Q, further increases the kinetics of fibril formation. However, detailed knowledge regarding the residues that are responsible for stabilizing the misfolded fibril structure is lacking. In this study, using solid-state NMR spectroscopy, we show that the majority of the AL-09 VL sequence is immobilized in the fibrils and that the N- and C-terminal portions of the sequence are particularly well-structured. Thus, AL-09 VL forms an extensively ordered and β-strand-rich fibril structure. Furthermore, we demonstrate that the predominant β-sheet secondary structure and rigidity observed for in vitro prepared AL-09 VL fibrils are qualitatively similar to those observed for AL fibrils extracted from postmortem human spleen tissue, suggesting that this conformation may be representative of a common feature of AL fibrils. PMID:28261692

A Computational Approach From Gene to Structure Analysis of the Human ABCA4 Transporter Involved in Genetic Retinal Diseases.

PubMed

Trezza, Alfonso; Bernini, Andrea; Langella, Andrea; Ascher, David B; Pires, Douglas E V; Sodi, Andrea; Passerini, Ilaria; Pelo, Elisabetta; Rizzo, Stanislao; Niccolai, Neri; Spiga, Ottavia

2017-10-01

The aim of this article is to report the investigation of the structural features of ABCA4, a protein associated with a genetic retinal disease. A new database collecting knowledge of ABCA4 structure may facilitate predictions about the possible functional consequences of gene mutations observed in clinical practice. In order to correlate structural and functional effects of the observed mutations, the structure of mouse P-glycoprotein was used as a template for homology modeling. The obtained structural information and genetic data are the basis of our relational database (ABCA4Database). Sequence variability among all ABCA4-deposited entries was calculated and reported as Shannon entropy score at the residue level. The three-dimensional model of ABCA4 structure was used to locate the spatial distribution of the observed variable regions. Our predictions from structural in silico tools were able to accurately link the functional effects of mutations to phenotype. The development of the ABCA4Database gathers all the available genetic and structural information, yielding a global view of the molecular basis of some retinal diseases. ABCA4 modeled structure provides a molecular basis on which to analyze protein sequence mutations related to genetic retinal disease in order to predict the risk of retinal disease across all possible ABCA4 mutations. Additionally, our ABCA4 predicted structure is a good starting point for the creation of a new data analysis model, appropriate for precision medicine, in order to develop a deeper knowledge network of the disease and to improve the management of patients.

H3.Y discriminates between HIRA and DAXX chaperone complexes and reveals unexpected insights into human DAXX-H3.3-H4 binding and deposition requirements

PubMed Central

Zink, Lisa-Maria; Delbarre, Erwan; Eberl, H. Christian; Keilhauer, Eva C.; Bönisch, Clemens; Pünzeler, Sebastian; Bartkuhn, Marek; Collas, Philippe; Mann, Matthias

2017-01-01

Abstract Histone chaperones prevent promiscuous histone interactions before chromatin assembly. They guarantee faithful deposition of canonical histones and functionally specialized histone variants into chromatin in a spatial- and temporally-restricted manner. Here, we identify the binding partners of the primate-specific and H3.3-related histone variant H3.Y using several quantitative mass spectrometry approaches, and biochemical and cell biological assays. We find the HIRA, but not the DAXX/ATRX, complex to recognize H3.Y, explaining its presence in transcriptionally active euchromatic regions. Accordingly, H3.Y nucleosomes are enriched in the transcription-promoting FACT complex and depleted of repressive post-translational histone modifications. H3.Y mutational gain-of-function screens reveal an unexpected combinatorial amino acid sequence requirement for histone H3.3 interaction with DAXX but not HIRA, and for H3.3 recruitment to PML nuclear bodies. We demonstrate the importance and necessity of specific H3.3 core and C-terminal amino acids in discriminating between distinct chaperone complexes. Further, chromatin immunoprecipitation sequencing experiments reveal that in contrast to euchromatic HIRA-dependent deposition sites, human DAXX/ATRX-dependent regions of histone H3 variant incorporation are enriched in heterochromatic H3K9me3 and simple repeat sequences. These data demonstrate that H3.Y's unique amino acids allow a functional distinction between HIRA and DAXX binding and its consequent deposition into open chromatin. PMID:28334823

Description and quantitative modeling of oolitic reservoir analogs within the lower Kansas City Group (Pennsylvanian), southeastern Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

French, J.A.; Watney, W.L.

A significant number of petroleum reservoirs within the Kansas City Group in central and western Kansas are dominantly oolitic grainstones that cap 10- to 30-m-thick, shallowing-upward, carbonate-rich depositional sequences. Coeval units that occur at and near the surface in southeastern Kansas contain similar porous lithofacies that have been examined in detail via cores, outcrops, and an extensive log database to better understand the equivalent reservoirs. These studies suggest that individual oolitic, reservoir-quality units in the Bethany Falls Limestone (equivalent to the K zone in the subsurface) developed at several relative sea level stands that occurred during development of a highstandmore » systems tract within this depositional sequence. As many as three grain-rich parasequences may occur at a given location. The occurrence of multiple parasequences indicates a relatively complex history of K-zone deposition, which likely resulted in significant effects on reservoir architecture. Two-dimensional forward modeling of this sequence with our interactive, PC-based software has revealed that limited combinations of parameters such as shelf configuration, eustasy, sedimentation rates, and subsidence rates generate strata successions similar to those observed. Sensitivity analysis coupled with regional characterization of processes suggest ranges of values that these parameters could have had during deposition of these units. The ultimate goal of this modeling is to improve our ability to predict facies development in areas of potential and known hydrocarbon accumulations.« less

27nt-RNAs guide histone variant deposition via 'RNA-induced DNA replication interference' and thus transmit parental genome partitioning in Stylonychia.

PubMed

Postberg, Jan; Jönsson, Franziska; Weil, Patrick Philipp; Bulic, Aneta; Juranek, Stefan Andreas; Lipps, Hans-Joachim

2018-06-12

During sexual reproduction in the unicellular ciliate Stylonychia somatic macronuclei differentiate from germline micronuclei. Thereby, programmed sequence reduction takes place, leading to the elimination of > 95% of germline sequences, which priorly adopt heterochromatin structure via H3K27me3. Simultaneously, 27nt-ncRNAs become synthesized from parental transcripts and are bound by the Argonaute protein PIWI1. These 27nt-ncRNAs cover sequences destined to the developing macronucleus and are thought to protect them from degradation. We provide evidence and propose that RNA/DNA base-pairing guides PIWI1/27nt-RNA complexes to complementary macronucleus-destined DNA target sequences, hence transiently causing locally stalled replication during polytene chromosome formation. This spatiotemporal delay enables the selective deposition of temporarily available histone H3.4K27me3 nucleosomes at all other sequences being continuously replicated, thus dictating their prospective heterochromatin structure before becoming developmentally eliminated. Concomitantly, 27nt-RNA-covered sites remain protected. We introduce the concept of 'RNA-induced DNA replication interference' and explain how the parental functional genome partition could become transmitted to the progeny.

Tidal sedimentation from a fluvial to estuarine transition, Douglas Group, Missourian -- Virgilian, Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanier, W.P.; Feldman, H.R.; Archer, A.W.

The Tonganoxie Sandstone Member of the Stranger Formation (Douglas Group, Upper Pennsylvanian, Kansas) was deposited in a funnel-shaped, northeast-southwest-trending paleovalley that was incised during the uppermost Missourian sealevel lowstand and backfilled during the subsequent transgression. Quarry exposures of the Tonganoxie near Ottawa, Kansas, include [approximately] 5 m of sheetlike, vertically accreted siltstones and sandy siltstones, bounded above and below by thin coals with upright plant fossils and paleosols. Strata range from submillimeter-thick, normally graded rhythmites to graded bedsets up to 12.5 cm thick with a vertical sedimentary structure sequence (VSS) consisting of the following intervals: (A) a basal massive tomore » normally graded interval; (B) a parallel-laminated interval; (C) a ripple-cross-laminated interval; and (D) an interval of draped lamination. The Tonganoxie succession has many similarities to fluvial overbank/floodplain deposits: sheetlike geometry, upright plant fossils, lack of bioturbation and body fossils, dominance of silt, and a punctuated style of rapid sedimentation from suspension-laden waning currents. Analysis of stratum-thickness variations through the succession suggests that tides significantly influenced sediment deposition. A fluvial-to-estuarine transitional depositional setting is interpreted for the Tonganoxie by analogy with modern depositional settings that show similar physical and biogenic sedimentary structures, vertical sequences of sedimentary structures, and aggradation rates.« less

Mitogenomes of Giant-Skipper Butterflies reveal an ancient split between deep and shallow root feeders.

PubMed

Zhang, Jing; Cong, Qian; Fan, Xiao-Ling; Wang, Rongjiang; Wang, Min; Grishin, Nick V

2017-01-01

Background: Giant-Skipper butterflies from the genus Megathymus are North American endemics. These large and thick-bodied Skippers resemble moths and are unique in their life cycles. Grub-like at the later stages of development, caterpillars of these species feed and live inside yucca roots. Adults do not feed and are mostly local, not straying far from the patches of yucca plants. Methods: Pieces of muscle were dissected from the thorax of specimens and genomic DNA was extracted (also from the abdomen of a specimen collected nearly 60 years ago). Paired-end libraries were prepared and sequenced for 150bp from both ends. The mitogenomes were assembled from the reads followed by a manual gap-closing procedure and a phylogenetic tree was constructed using a maximum likelihood method from an alignment of the mitogenomes. Results: We determined mitogenome sequences of nominal subspecies of all five known species of Megathymus and Agathymus mariae to confidently root the phylogenetic tree. Pairwise sequence identity indicates the high similarity, ranging from 88-96% among coding regions for 13 proteins, 22 tRNAs and 2 rRNA, with a gene order typical for mitogenomes of Lepidoptera. Phylogenetic analysis confirms that Giant-Skippers (Megathymini) originate within the subfamily Hesperiinae and do not warrant a subfamily rank. Genus Megathymus is monophyletic and splits into two species groups. M. streckeri and M. cofaqui caterpillars feed deep in the main root system of yucca plants and deposit frass underground. M. ursus , M. beulahae and M. yuccae feed in the yucca caudex and roots near the ground, and deposit frass outside through a "tent" (a silk tube projecting from the center of yucca plant). M. yuccae and M. beulahae are sister species consistently with morphological similarities between them. Conclusions: We constructed the first DNA-based phylogeny of the genus Megathymus from their mitogenomes. The phylogeny agrees with morphological considerations.

Illumina sequencing of fungi associated with manganese oxide deposits in cave systems

NASA Astrophysics Data System (ADS)

Zorn, B. T.; Santelli, C. M.; Carmichael, S. K.; Pepe-Ranney, C. P.; Roble, L.; Carmichael, M.; Bräuer, S.

2013-12-01

The environmental cycling of manganese (Mn) remains relatively poorly characterized when compared with other metals such as iron. However, fungi have been observed to produce Mn(III/IV) oxides resembling buserite, birnessite, and todorokite on the periphery of vegetative hyphae, hyphal branching points and at the base of fruiting bodies. Recent studies indicate that some of these oxides may be generated by a two-stage reaction with soluble Mn(II) and biogenic reactive oxygen species for some groups of fungi, in particular the Ascomycota. These oxides can provide a versatile protective barrier or aid in the capture of trace metals in the environment, although the exact evolutionary function and trigger is unclear. In this study, two caves in the southern Appalachians, a pristine cave and an anthropogenically impacted cave, were compared by analyzing fungal community assemblages in manganese oxide rich deposits. Quantitative PCR data indicated that fungi are present in a low abundance (<1%) in all locations sampled within the caves. Among amplified DNA sequences retrieved in an 18S rDNA clone library, over 88% were representative of the phylum Basidiomycota (predominantly Agaricomycetes), 2.74% of Ascomycota, 2.28% of Blastocladiomycota and Chytridiomycota, 0.46% of Zygomycota, and 3.65% of Eukarya or Fungi incertae sedis. Using Illumina's MiSeq to sequence amplicons of the fungal ITS1 gene has yielded roughly 100,000-200,000 paired-end reads per sample. These data are currently being analyzed to compare fungal communities before and after induced Mn oxidation in the field. In addition, sites within the pristine cave are being compared with analogous sites in the impacted cave. Culturing efforts have thus far yielded Mn oxide producing members of the orders Glomerales and Pleosporales as well as two Genus incertae sedis (Fungal sp. YECT1, and Fungal sp. YECT3, growing on discarded electrical tape) that do not appear to be closely related to any other known Mn oxidizing fungi.

Disentangling the control of tectonics, eustasy, trophic conditions and climate on shallow-marine carbonate production during the Aalenian-Oxfordian interval: From the western France platform to the western Tethyan domain

NASA Astrophysics Data System (ADS)

Andrieu, Simon; Brigaud, Benjamin; Barbarand, Jocelyn; Lasseur, Eric; Saucède, Thomas

2016-11-01

The objective of this work is to improve our understanding of the processes controlling changes in the architecture and facies of intracontinental carbonate platforms. We examined the facies and sequence stratigraphy of Aalenian to Oxfordian limestones of western France. Seventy-seven outcrop sections were studied and thirty-one sedimentary facies identified in five depositional environments ranging from lower offshore to backshore. Platform evolution was reconstructed along a 500 km cross-section. Twenty-two depositional sequences were identified on the entire western France platform and correlated with European third-order sequences at the biozone level, demonstrating that eustasy was the major factor controlling the cyclic trend of accommodation. The tectonic subsidence rate was computed from accommodation measurements from the Aalenian to the Oxfordian in key localities. Tectonism controlled the sedimentation rate and platform architecture at a longer time scale. Tectonic subsidence triggered the demise of carbonate production at the Bathonian/Callovian boundary while the uplift made possible the recovery of carbonate platform from Caen to Le Mans during the mid Oxfordian. Topography of the Paleozoic basement mainly controlled lateral variations of paleodepth within the western France platform until the mid Bathonian. A synthesis of carbonate production in the western Tethyan domain at that time was conducted. Stages of high carbonate production during the Bajocian/Bathonian and the middle to late Oxfordian are synchronous with low δ13C, high eccentricity intervals, and rather dry climate promoting (1) evaporation and carbonate supersaturation, and (2) oligotrophic conditions. Periods of low carbonate production during the Aalenian and from the middle Callovian to early Oxfordian correlate with high δ13C and low eccentricity intervals, characterized by wet climate and less oligotrophic conditions. Such conditions tend to diminish growth potential of carbonate platforms. This work highlights the importance of climate control on carbonate growth and demise at large scale in western Tethyan epicontinental seas.

46 CFR 502.287 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 9 2011-10-01 2011-10-01 false Depositions. 502.287 Section 502.287 Shipping FEDERAL... Investigations § 502.287 Depositions. The Commission, or its duly authorized representative, may order testimony to be taken by deposition in any investigation at any stage of such investigation. Such depositions...

7 CFR 900.61 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Depositions. 900.61 Section 900.61 Agriculture... Governing Proceedings on Petitions To Modify or To Be Exempted From Marketing Orders § 900.61 Depositions. (a) Procedure in lieu of deposition. Before any party may have testimony taken by deposition, said...

7 CFR 900.61 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Depositions. 900.61 Section 900.61 Agriculture... Governing Proceedings on Petitions To Modify or To Be Exempted From Marketing Orders § 900.61 Depositions. (a) Procedure in lieu of deposition. Before any party may have testimony taken by deposition, said...

46 CFR 502.287 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 9 2010-10-01 2010-10-01 false Depositions. 502.287 Section 502.287 Shipping FEDERAL... Investigations § 502.287 Depositions. The Commission, or its duly authorized representative, may order testimony to be taken by deposition in any investigation at any stage of such investigation. Such depositions...

Influence of annealing temperature on structural and magnetic properties of pulsed laser-deposited YIG films on SiO2 substrate

NASA Astrophysics Data System (ADS)

Nag, Jadupati; Ray, Nirat

2018-05-01

Yttrium Iron Garnet (Y3Fe5O12) was synthesized by solid state/ceramic process. Thin films of YIG were deposited on SiO2 substrate at room temperature(RT) and at substrate temperature (Ts) 700 °C using pulsed laser deposition (PLD) technique. RT deposited thin films are amorphous in nature and non-magnetic. After annealing at temperature 800 ° RT deposited thin films showed X-ray peaks as well as the magnetic order. Magnetic ordering is enhanced by annealing temperature(Ta ≥ 750 °C) and resulted good quality of films with high magnetization value.

The Diversity Present in 5140 Human Mitochondrial Genomes

PubMed Central

Pereira, Luísa; Freitas, Fernando; Fernandes, Verónica; Pereira, Joana B.; Costa, Marta D.; Costa, Stephanie; Máximo, Valdemar; Macaulay, Vincent; Rocha, Ricardo; Samuels, David C.

2009-01-01

We analyzed the current status (as of the end of August 2008) of human mitochondrial genomes deposited in GenBank, amounting to 5140 complete or coding-region sequences, in order to present an overall picture of the diversity present in the mitochondrial DNA of the global human population. To perform this task, we developed mtDNA-GeneSyn, a computer tool that identifies and exhaustedly classifies the diversity present in large genetic data sets. The diversity observed in the 5140 human mitochondrial genomes was compared with all possible transitions and transversions from the standard human mitochondrial reference genome. This comparison showed that tRNA and rRNA secondary structures have a large effect in limiting the diversity of the human mitochondrial sequences, whereas for the protein-coding genes there is a bias toward less variation at the second codon positions. The analysis of the observed amino acid variations showed a tolerance of variations that convert between the amino acids V, I, A, M, and T. This defines a group of amino acids with similar chemical properties that can interconvert by a single transition. PMID:19426953

Sympodiomycopsis lanaiensis sp. nov., a basidiomycetous yeast (Ustilaginomycotina: Microstromatales) from marine driftwood in Hawai‘i

PubMed Central

Mahdi, Leena E.; Statzell-Tallman, Adele; Fell, Jack W.; Brown, Mark V.; Donachie, Stuart P.

2009-01-01

A previously unknown basidiomycetous yeast is described for which the name Sympodiomycopsis lanaiensis is proposed. The type strain, LM418T, was isolated from driftwood collected on a beach on Lana‘i (Hawai‘i). On the basis of ribosomal DNA sequence analysis [large subunit (LSU), internal transcribed spacer (ITS) 1 & 2, and 18S], LM418T belongs to the order Microstromatales, which includes the genera Sympodiomycopsis, Rhodotorula, Microstroma, Volvocisporium and Quambalaria. The strain is described as a new species in the genus Sympodiomycopsis on the basis of morphological and physiological characteristics and the phylogenetic relationship to Sympodiomycopsis paphiopedili. Sexual reproduction was not observed in LM418T. GenBank accession numbers for nucleotide sequences of regions of the LSU, ITS and 18S regions of the ribosomal operon in LM418T are DQ990016, DQ990017 and DQ990018, respectively. LM418T has been deposited in the DSMZ as DSM 18755, in the ATCC as MYA-4092, in the Agricultural Research Service Culture Collection as NRRL Y-48466, and the Centraalbureau voor Schimmelcultures as CBS 10858. PMID:19054136

Process in manufacturing high efficiency AlGaAs/GaAs solar cells by MO-CVD

NASA Technical Reports Server (NTRS)

Yeh, Y. C. M.; Chang, K. I.; Tandon, J.

1984-01-01

Manufacturing technology for mass producing high efficiency GaAs solar cells is discussed. A progress using a high throughput MO-CVD reactor to produce high efficiency GaAs solar cells is discussed. Thickness and doping concentration uniformity of metal oxide chemical vapor deposition (MO-CVD) GaAs and AlGaAs layer growth are discussed. In addition, new tooling designs are given which increase the throughput of solar cell processing. To date, 2cm x 2cm AlGaAs/GaAs solar cells with efficiency up to 16.5% were produced. In order to meet throughput goals for mass producing GaAs solar cells, a large MO-CVD system (Cambridge Instrument Model MR-200) with a susceptor which was initially capable of processing 20 wafers (up to 75 mm diameter) during a single growth run was installed. In the MR-200, the sequencing of the gases and the heating power are controlled by a microprocessor-based programmable control console. Hence, operator errors can be reduced, leading to a more reproducible production sequence.

The volcanic-sedimentary sequence of the Lousal deposit, Iberian Pyrite Belt (Portugal)

NASA Astrophysics Data System (ADS)

Rosa, Carlos; Rosa, Diogo; Matos, Joao; Relvas, Jorge

2010-05-01

The Iberian Pyrite Belt (IPB) is a massive sulfide province that is located in the south of Portugal and Spain, and hosts more than 90 massive sulfide deposits that amount to more than 1850 million metric tonnes of sulfide ore (Tornos, 2006). The ore deposits size, vary from ~1Mt to >100Mt (e.g. Neves Corvo and Aljustrel in Portugal, and Rio Tinto and Tharsis in Spain). The ore deposits are hosted by a submarine sedimentary and volcanic, felsic dominated, succession that constitutes the Upper Devonian to Lower Carboniferous Volcanic and Sedimentary Complex (VSC). The VSC ranges in thickness from approximately 600 to 1300 m (Tornos 2006). The VSC overlies the Phyllite-Quartzite Group (PQ) (Upper Devonian, base unknown) and is overlain by the Baixo Alentejo Flysch Group (Lower to Upper Carboniferous). The Lousal massive sulfide deposit is located in the western part of the IPB and occurs mostly interbedded with black mudstone. The VSC sequence at Lousal mine consists of a mudstone and quartzite sequence (PQ Group) in the lower part of the succession, over which a thick sequence of rhyolitic lavas (>300 m) occurs. Above the rhyolitic lavas there is a thick sequence of black and grey mudstone that hosts the massive sulfide ore bodies, and a rhyolitic sill. The upper part of the VSC sequence consists of a thick mudstone interval that hosts two thick basaltic units, locally with pillows. The rhyolites have small coherent cores, locally with flow bands, that grade to surrounding massive clastic intervals, with large lateral extent. The clasts show jigsaw-fit arrangement in many places and have planar or curviplanar margins and locally are perlitic at the margin. The top contact of these units is in most locations not exposed, which makes difficult to interpret the mode of emplacement. However, the thick clastic intervals, above described, are in accordance with quenching of volcanic glass with abundant water and therefore indicate that quenching of the rhyolites was the dominant fragmentation mechanism. Unlike many locations of the IPB, fiamme-rich pyroclastic units were not identified at Lousal. The ore deposits occur in close proximity with this volcanic centre that may have driven hydrothermal circulation that led to ore formation. The volcanic rocks show intense chloritic alteration, indicating that the mineralizing event occurred after most of the rhyolitic units have emplaced. The massive sulfides show abundant sedimentary structures which is not typical in the massive sulfide deposits of the IPB. The Lousal 50 Mt massive sulfide deposit consists of at least 11 ore bodies and was exploited until 1988 mainly for pyrite. The ores mined averaged 0.7% Cu, 0.8%Pb e 1.4%Zn (Strauss, 1971). These relatively low base metal grades led to an evaluation of the contents and distribution of high-tech element in the ore bodies, which would improve the economic viability of mining the deposit. This evaluation is currently focusing on the distribution and mineralogy of selenium, as ores mined in the past were known to be rich in this element. This work benefits from research projects INCA (PTDC/CTE-GIN/67027/2006; Characterization of crucial mineral resources for the development of renewable energy technologies: The Iberian Pyrite Belt ores as a source of indium and other high-technology elements) and project ARCHYMEDES II (POCTI/CTA/45873/2002), both funded by the Fundação para a Ciência e Tecnologia. REFERENCES Strauss, G.K., 1970. Sobre la geologia de la provincia piritifera del Suroeste de la Peninsula Iberica y sus yacimientos, en especial sobre la mina de pirita de Lousal (Portugal): Memoria del IGME 77, 1-266. Tornos, F., 2006. Environment of formation and styles of volcanogenic massive sulfides: The Iberian Pyrite Belt. Ore Geology Reviews 28, 259-307.

Characterization and correction of eddy-current artifacts in unipolar and bipolar diffusion sequences using magnetic field monitoring.

PubMed

Chan, Rachel W; von Deuster, Constantin; Giese, Daniel; Stoeck, Christian T; Harmer, Jack; Aitken, Andrew P; Atkinson, David; Kozerke, Sebastian

2014-07-01

Diffusion tensor imaging (DTI) of moving organs is gaining increasing attention but robust performance requires sequence modifications and dedicated correction methods to account for system imperfections. In this study, eddy currents in the "unipolar" Stejskal-Tanner and the velocity-compensated "bipolar" spin-echo diffusion sequences were investigated and corrected for using a magnetic field monitoring approach in combination with higher-order image reconstruction. From the field-camera measurements, increased levels of second-order eddy currents were quantified in the unipolar sequence relative to the bipolar diffusion sequence while zeroth and linear orders were found to be similar between both sequences. Second-order image reconstruction based on field-monitoring data resulted in reduced spatial misalignment artifacts and residual displacements of less than 0.43 mm and 0.29 mm (in the unipolar and bipolar sequences, respectively) after second-order eddy-current correction. Results demonstrate the need for second-order correction in unipolar encoding schemes but also show that bipolar sequences benefit from second-order reconstruction to correct for incomplete intrinsic cancellation of eddy-currents. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Well-Ordered In Adatoms at the In 2 O 3 ( 111 ) Surface Created by Fe Deposition

DOE PAGES

Wagner, Margareta; Lackner, Peter; Seiler, Steffen; ...

2016-11-11

Metal deposition on oxide surfaces usually results in adatoms, clusters, or islands of the deposited material, where defects in the surface often act as nucleation centers. An alternate configuration is reported. Afterwards the vapor deposition of Fe on the In 2O 3(111) surface at room temperature, ordered adatoms are observed with scanning tunneling microscopy (STM). These are identical to the In adatoms that form when the sample is reduced by heating in ultrahigh vacuum. Our density functional theory (DFT) calculations confirm that Fe interchanges with In in the topmost layer, pushing the excess In atoms to the surface where theymore » arrange as a well-ordered adatom array.« less

[Archaeal diversity in permafrost deposits of Bunger Hills Oasis and King George Island (Antarctica) according to the 16S rRNA gene sequencing].

PubMed

Karaevskaia, E S; Demchenko, L S; Demidov, N É; Rivkina, E M; Bulat, S A; Gilichinskiĭ, D A

2014-01-01

Archaeal communities of permafrost deposits of King George Island and Bunger Hills Oasis (Antarctica) differing in the content of biogenic methane were analyzed using clone libraries of two 16S rRNA gene regions. Phylotypes belonging to methanogenic archaea were identified in all horizons.

25 CFR 571.11 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Depositions. 571.11 Section 571.11 Indians NATIONAL... INVESTIGATIONS Subpoenas and Depositions § 571.11 Depositions. (a) Any party wishing to depose a witness shall... shown. A Commissioner or a presiding official may order testimony to be taken by deposition in any...

39 CFR 955.17 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 39 Postal Service 1 2011-07-01 2011-07-01 false Depositions. 955.17 Section 955.17 Postal Service... APPEALS § 955.17 Depositions. (a) When depositions permitted. After an appeal has been docketed and... for good cause shown, order the taking of testimony of any person by deposition upon oral examination...

15 CFR 904.241 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Depositions. 904.241 Section 904.241... and Appeal Procedures Discovery § 904.241 Depositions. (a) Notice. If a motion for deposition is granted, and unless otherwise ordered by the Judge, the party taking the deposition of any person must...

41 CFR 60-30.11 - Depositions upon oral examination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Depositions upon oral... EXECUTIVE ORDER 11246 Prehearing Procedures § 60-30.11 Depositions upon oral examination. (a) Depositions..., including a party, having personal or expert knowledge of the matters in issue, by deposition upon oral...

15 CFR 904.241 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Depositions. 904.241 Section 904.241... and Appeal Procedures Discovery § 904.241 Depositions. (a) Notice. If a motion for deposition is granted, and unless otherwise ordered by the Judge, the party taking the deposition of any person must...

16 CFR 1605.7 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Depositions. 1605.7 Section 1605.7... Inquiries § 1605.7 Depositions. (a) The Commission may order and, by subpoena, may compel testimony to be taken by deposition at any stage of any investigation. Such depositions may be taken before any person...

41 CFR 60-30.11 - Depositions upon oral examination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Depositions upon oral... EXECUTIVE ORDER 11246 Prehearing Procedures § 60-30.11 Depositions upon oral examination. (a) Depositions..., including a party, having personal or expert knowledge of the matters in issue, by deposition upon oral...

39 CFR 955.17 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 39 Postal Service 1 2010-07-01 2010-07-01 false Depositions. 955.17 Section 955.17 Postal Service... APPEALS § 955.17 Depositions. (a) When depositions permitted. After an appeal has been docketed and... for good cause shown, order the taking of testimony of any person by deposition upon oral examination...

27 CFR 71.125 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Depositions. 71.125... Miscellaneous § 71.125 Depositions. The administrative law judge may take or order the taking of depositions by... testimony shall be reduced to writing by the person taking the deposition, or under his direction, and the...

25 CFR 571.11 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 25 Indians 2 2011-04-01 2011-04-01 false Depositions. 571.11 Section 571.11 Indians NATIONAL... INVESTIGATIONS Subpoenas and Depositions § 571.11 Depositions. (a) Any party wishing to depose a witness shall... shown. A Commissioner or a presiding official may order testimony to be taken by deposition in any...

27 CFR 71.125 - Depositions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 2 2011-04-01 2011-04-01 false Depositions. 71.125... Miscellaneous § 71.125 Depositions. The administrative law judge may take or order the taking of depositions by... testimony shall be reduced to writing by the person taking the deposition, or under his direction, and the...

16 CFR 1605.7 - Depositions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Depositions. 1605.7 Section 1605.7... Inquiries § 1605.7 Depositions. (a) The Commission may order and, by subpoena, may compel testimony to be taken by deposition at any stage of any investigation. Such depositions may be taken before any person...

Anatomy of a mountain: The Thebes Limestone Formation (Lower Eocene) at Gebel Gurnah, Luxor, Nile Valley, Upper Egypt

NASA Astrophysics Data System (ADS)

King, Christopher; Dupuis, Christian; Aubry, Marie-Pierre; Berggren, William A.; Knox, Robert O.'B.; Galal, Wael Fathi; Baele, Jean-Marc

2017-12-01

We present a detailed geologic study of the Thebes Formation at Gebel Gurnah in its locus typicus on the West Bank (opposite Luxor) of the Nile River in the Upper Nile Valley, Egypt. This is the first detailed measurement and lithologic description of the ∼340 m thick (predominantly) carbonate section. The Thebes Formation is divided into thirteen major lithic units (A to M). We interpret data on the lithologic succession and variations, whole rock/clay mineralogy, and macro/micropaleontology in terms of deposition on a shallow carbonate platform episodically influenced by continental runoff, and describe six depositional sequences that we place in the global framework of Lower Eocene (Ypresian) sequence stratigraphy. We note however significant incompatibilities between the Thebes depositional sequences and the global sequences. We emend the definition of the Thebes Formation by defining its top as corresponding to level 326 m at the top of Nodular Limestone 'L' (NLL), and assigning the overlying beds to the Minia Limestone Formation. New biostratigraphic data and revision of previous studies establish the direct assignment of the Thebes Formation to planktonic foraminiferal Zones E4/P6b (upper part), E5/P7 and (indirectly) Zone E6/P8, and (probably, indirectly) Zone E7a/;P9;, and to calcareous nannofossil Zone NP12 and lower Zone NP13 of the Lower Eocene (Ypresian) and provide a temporal framework spanning ∼ 2.8 Myr from <52.45 to ∼49.6 Ma for the deposition of the Thebes Formation prior to the prominent sea level fall (∼49.6 Ma) towards the end of the Early Eocene. Dominantly carbonate deposition, with a strongly reduced detrital influx, occurred on a very wide shelf (probably) at least ∼ 100 km from the coastline. The thick sedimentary succession and the marked vertical lithologic variations are interpreted as resulting from sea level fluctuations imprinted on a long-term decrease in sea-level associated with rapid subsidence reflecting tectonic relaxation after the major Late Paleocene tectonic reorganization of the Syrian Arc.

Lithofacies, paleoenvironment and high-resolution stratigraphy of the D5 and D6 members of the Middle Jurassic carbonates Dhruma Formation, outcrop analog, central Saudi Arabia

NASA Astrophysics Data System (ADS)

Yousif, Ibrahim M.; Abdullatif, Osman M.; Makkawi, Mohammad H.; Bashri, Mazin A.; Abdulghani, Waleed M.

2018-03-01

This study characterizes the lithofacies, paleoenvironment and stratigraphic architecture of the D5 and D6 members of carbonates Dhruma Formation outcrops in central Saudi Arabia. The study integrates detailed lithofacies analysis based on vertical and lateral profiles, in addition to thin-sections petrography to reveal the high-resolution architecture framework. Nine lithofacies types (LFTs) were defined namely: (1) skeletal peletal spiculitic wackestone (15%), (2) peloidal echinoderm packstone (19%), (3) fissile shale (36%), (4) peloidal spiculitic echinoderm pack-grainstone (5%), (5) cross-bedded peloidal skeletal oolitic grainstone (7%), (6) oolitic grainstone (2%), (7) intraformational rudstone (<1%), (8) skeletal peloidal foraminiferal packstone (12%) and (9) skeletal foraminiferal wackestone (4%). These lithofacies types were grouped into five major carbonate paleoenvironments that range from distal-to-proximal carbonate ramp setting. The detailed stratigraphic analysis revealed around 53 cycles and cycle sets with 5th to 6th orders magnitude, and thickness ranges from a few centimeters up to 6 m with an average of 1.5 m. Those are stacked to form four high-frequency sequences with thickness range from 1 m up to 14 m. The latter were grouped into a single depositional sequence of 3rd order magnitude. The architectural analysis also shows that the potential reservoir units were intensively affected by muddy-textured rocks which act as reservoir seals. These variations in the stratigraphic sequences in Middle Jurassic Dhruma Formation and its equivalents could be attributed to the eustatic sea-level changes, climate, tectonics, and local paleoenvironments. This study attempts to provide detailed insight into reservoir heterogeneity and architecture. The analog may help to understand and predict lithofacies heterogeneity, architecture, and quality in the subsurface equivalent reservoirs.

Atmospheric Mg2+ wet deposition within the continental United States and implications for soil inorganic carbon sequestration

NASA Astrophysics Data System (ADS)

Goddard, Megan A.; Mikhailova, Elena A.; Post, Christopher J.; Schlautman, Mark A.

2007-02-01

Little is known about atmospheric magnesium ion (Mg2+) wet deposition in relation to soil inorganic carbon sequestration. Understanding the conversion of carbon dioxide (CO2) or organic carbon to a form having a long residence time within the soil (e.g., dolomite, magnesian calcite) will greatly benefit agriculture, industry, and society on a global scale. This preliminary study was conducted to analyze atmospheric Mg2+ wet deposition within the continental United States (U.S.) and to rank the twelve major soil orders in terms of average annual atmospheric Mg2+ wet deposition. The total average annual Mg2+ wet deposition for each soil order was estimated with geographic information systems (GIS) using the following data layers: (1) atmospheric Mg2+ wet deposition data layers covering the continental U.S. for a 10-yr period (1994-2003) and (2) a soil order data layer derived from a national soils database. A map of average annual Mg2+ wet deposition for 1994-2003 reveals that the highest deposition (0.75-1.41 kg ha-1) occurred in Oregon, Washington, parts of California, and the coastal areas of East Coast states due to magnesium enrichment of atmospheric deposition from sea salt. The Midwestern region of the U.S. received about 0.25-0.75 kg ha-1 Mg2+ wet deposition annually, which was associated with loess derived soils, occurrence of dust storms and possibly fertilization. The soil orders receiving the highest average annual atmospheric Mg2+ wet deposition from 1994 to 2003 were: (1) Mollisols (3.7 × 107 kg), (2) Alfisols (3.6 × 107 kg) and (3) Ultisols (2.8 × 107 kg). In terms of potential soil carbon sequestration, the average annual atmospheric Mg2+ wet deposition was equivalent to formation of the following theoretical amounts of dolomite: (1) Mollisols (2.8 × 108 kg of CaMg(CO3)2), (2) Alfisols (2.7 × 108 kg of CaMg(CO3)2) and (3) Ultisols (2.1 × 108 kg of CaMg(CO3)2). The soil orders receiving the lowest average annual atmospheric Mg2+ wet deposition were: (1) Andisols (3.3 × 106 kg), (2) Histosols (3.4 × 106 kg) and (3) Vertisols (5.0 × 106 kg). The methods proposed here to estimate soil inorganic carbon sequestration potential from atmospheric wet deposition data can be useful for preliminary carbon accounting on a global scale.

Structural, mineralogical and geochemical constraints on the atypical komatiite-hosted Turret deposit in the Agnew-Mt. White district, Western Australia

NASA Astrophysics Data System (ADS)

Voute, F.; Thébaud, N.

2015-08-01

In the Norseman-Wiluna belt, Yilgarn Craton, the Agnew-Mt. White district is the host of many gold deposits. Located in the hinge of the regional Lawlers anticline, the Turret gold deposit is structurally controlled by the Table Hill shear zone that transects the Agnew Ultramafic unit. Geochemistry, coupled with petrographic data, allowed the delineation of the paragenetic sequence associated with gold mineralisation and include (1) a pervasive talc-carbonate alteration assemblage, (2) a pre-mineralisation stage associated with pervasive arsenopyrite + chalcopyrite + pyrrhotite + pyrite alteration, followed by (3) a late deformation event along a dilatational segment of the main Table Hill shear zone, leading to the formation of a breccia hosting a Cu-Bi-Mo-Au (± Ag ± Zn ± Te ± W) metal assemblage. The presence of Au-Ag-Cu alloys, native bismuth, chalcopyrite and other Bi-Te-S phases in the mineralisation stage suggest that gold may have been scavenged from the hydrothermal fluids by composite Bi-Te-Cu-Au-Ag-S liquids or melts. Using this mineral paragenetic sequence, together with mineralogical re-equilibration textures observed, we show that the gold deposition at Turret occurred over a temperature range approximately between c. 350 and 270 °C. This temperature range, together with the structural control and typical mesothermal alteration pattern including carbonate-chlorite alteration, shows that the Turret deposit shares common characteristics with the orogenic gold deposit class. However, the metal association of Cu, Au, Bi, and Mo, the quartz-poor, and high copper-sulphide content (up to 15 %) are characteristics that depart from the typical orogenic gold deposit mineralogy. Through comparison with similar deposits in the Yilgarn Craton and worldwide, we propose that the Turret deposit represents an example of a porphyry-derived Au-Cu-Bi-Mo deposit.

Stratigraphy and Facies of Cretaceous Schrader Bluff and Prince Creek Formations in Colville River Bluffs, North Slope, Alaska

USGS Publications Warehouse

Flores, Romeo M.; Myers, Mark D.; Houseknecht, David W.; Stricker, Gary D.; Brizzolara, Donald W.; Ryherd, Timothy J.; Takahashi, Kenneth I.

2007-01-01

Stratigraphic and sedimentologic studies of facies of the Upper Cretaceous rocks along the Colville River Bluffs in the west-central North Slope of Alaska identified barrier shoreface deposits consisting of vertically stacked, coarsening-upward parasequences in the Schrader Bluff Formation. This vertical stack of parasequence deposits represents progradational sequences that were affected by shoaling and deepening cycles caused by fluctuations of sea level. Further, the vertical stack may have served to stabilize accumulation of voluminous coal deposits in the Prince Creek Formation, which formed braided, high-sinuosity meandering, anastomosed, and low-sinuosity meandering fluvial channels and related flood plain deposits. The erosional contact at the top of the uppermost coarsening-upward sequence, however, suggests a significant drop of base level (relative sea level) that permitted a semiregional subaerial unconformity to develop at the contact between the Schrader Bluff and Prince Creek Formations. This drop of relative sea level may have been followed by a relative sea-level rise to accommodate coal deposition directly above the unconformity. This rise was followed by a second drop of relative sea level, with formation of incised valley topography as much as 75 ft deep and an equivalent surface of a major marine erosion or mass wasting, or both, either of which can be traced from the Colville River Bluffs basinward to the subsurface in the west-central North Slope. The Prince Creek fluvial deposits represent late Campanian to late Maastrichtian depositional environments that were affected by these base level changes influenced by tectonism, basin subsidence, and sea-level fluctuations.

Algeria: structural evolution and hydrocarbon potential of a complicated Tectonic province

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knudsen, H.W.

1985-02-01

During most of the pre-Carboniferous, Algeria was part of a stable foreland platform on which a thick clastic sequence was deposited. Caledonian tectonics were primarily epeirogenic, but they established structural alignments that were further reinforced by the much stronger movements of the Carboniferous Hercynian orogeny. In northern and eastern Algeria, a variable basal sandstone and a thick sequence of Triassic and Lower Jurassic evaporites were deposited over the eroded Hercynian surface. This provided a seal for subsequent hydrocarbon migration from the underlying Silurian and Devonian source rocks. Important epeirogenic events and tensional faulting occurred during the Jurassic and Cretaceous. Compressionalmore » forces in the tertiary culminated in the Alpine orogeny. A broad zone of uplift and southward-directed imbricate thrusting formed along the northern margins of Algeria obscuring much of the sub-Tertiary depositional and structural features. Hydrocarbon accumulation in Algeria has been predominantly controlled by the relationships among the Silurian-Devonian source rocks, the Hercynian unconformity, and the distribution of the overlying Triassic clastic and evaporite sequence. More than 65% of the recoverable oil reserves and 90% of the gas reserves are trapped immediately below or above the Hercynian unconformity, with the evaporites providing the seal. Heretofore, the complex geology of the Tertiary overthrust zone has been a deterrent to exploration in both the autochthonous Miocene basins and the sub-Tertiary sequence. However, improved seismic techniques and renewed interest in the potential of overthrust provinces point to increased activity in this area.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mello, M.R.; Soldan, A.L.; Maxwell, J.R.

A geochemical and biological marker investigation of a variety of oils from offshore Brazil and west Africa, ranging in age from Lower Cretaceous to Tertiary, has been done, with the following aims: (1) assessing the depositional environment of source rocks, (2) correlating the reservoired oils, (3) comparing the Brazilian oils with their west African counterparts. The approach was based in stable isotope data; bulk, elemental, and hydrous pyrolysis results; and molecular studies involving quantitative geological marker investigations of alkanes using GC-MS and GC-MS-MS. The results reveal similarities between groups of oils from each side of the Atlantic and suggest anmore » origin from source rocks deposited in five types of depositional environment: lacustrine fresh water, lacustrine saline water, marine evaporitic/carbonate, restricted marine anoxic, and marine deltaic. In west Africa, the Upper Cretaceous marine anoxic succession (Cenomanian-Santonian) appears to be a major oil producer, but in Brazil it is generally immature. The Brazilian offshore oils have arisen mainly from the pre-salt sequence, whereas the African oils show a balance between origins from the pre-salt and marine sequences. The integration of the geochemical and geological data indicate that new frontiers of hydrocarbon exploration in the west African basins must consider the Tertiary reservoirs in the offshore area of Niger Delta, the reservoirs of the rift sequences in the shallow-water areas of south Gabon, Congo, and Cuanza basins, and the reservoirs from the drift sequences (post-salt) in the deep-water areas of Gabon, Congo Cabinda, and Cuanza basins.« less

Relationships between palaeogeography and opal occurrence in Australia: A data-mining approach

NASA Astrophysics Data System (ADS)

Landgrebe, T. C. W.; Merdith, A.; Dutkiewicz, A.; Müller, R. D.

2013-07-01

Age-coded multi-layered geological datasets are becoming increasingly prevalent with the surge in open-access geodata, yet there are few methodologies for extracting geological information and knowledge from these data. We present a novel methodology, based on the open-source GPlates software in which age-coded digital palaeogeographic maps are used to “data-mine” spatio-temporal patterns related to the occurrence of Australian opal. Our aim is to test the concept that only a particular sequence of depositional/erosional environments may lead to conditions suitable for the formation of gem quality sedimentary opal. Time-varying geographic environment properties are extracted from a digital palaeogeographic dataset of the eastern Australian Great Artesian Basin (GAB) at 1036 opal localities. We obtain a total of 52 independent ordinal sequences sampling 19 time slices from the Early Cretaceous to the present-day. We find that 95% of the known opal deposits are tied to only 27 sequences all comprising fluvial and shallow marine depositional sequences followed by a prolonged phase of erosion. We then map the total area of the GAB that matches these 27 opal-specific sequences, resulting in an opal-prospective region of only about 10% of the total area of the basin. The key patterns underlying this association involve only a small number of key environmental transitions. We demonstrate that these key associations are generally absent at arbitrary locations in the basin. This new methodology allows for the simplification of a complex time-varying geological dataset into a single map view, enabling straightforward application for opal exploration and for future co-assessment with other datasets/geological criteria. This approach may help unravel the poorly understood opal formation process using an empirical spatio-temporal data-mining methodology and readily available datasets to aid hypothesis testing.

A Simple Method for Visualization of Locus-Specific H4K20me1 Modifications in Living Caenorhabditis elegans Single Cells.

PubMed

Shinkai, Yoichi; Kuramochi, Masahiro; Doi, Motomichi

2018-05-03

Recently, advances in next-generation sequencing technologies have enabled genome-wide analyses of epigenetic modifications; however, it remains difficult to analyze the states of histone modifications at a single-cell resolution in living multicellular organisms because of the heterogeneity within cellular populations. Here we describe a simple method to visualize histone modifications on the specific sequence of target locus at a single-cell resolution in living Caenorhabditis elegans , by combining the LacO/LacI system and a genetically-encoded H4K20me1-specific probe, "mintbody". We demonstrate that Venus-labeled mintbody and mTurquoise2-labeled LacI can co-localize on an artificial chromosome carrying both the target locus and LacO sequences, where H4K20me1 marks the target locus. We demonstrate that our visualization method can precisely detect H4K20me1 depositions on the her-1 gene sequences on the artificial chromosome, to which the dosage compensation complex binds to regulate sex determination. The degree of H4K20me1 deposition on the her-1 sequences on the artificial chromosome correlated strongly with sex, suggesting that, using the artificial chromosome, this method can reflect context-dependent changes of H4K20me1 on endogenous genomes. Furthermore, we demonstrate live imaging of H4K20me1 depositions on the artificial chromosome. Combined with ChIP assays, this mintbody-LacO/LacI visualization method will enable analysis of developmental and context-dependent alterations of locus-specific histone modifications in specific cells and elucidation of the underlying molecular mechanisms. Copyright © 2018, G3: Genes, Genomes, Genetics.

Early rifting deposition: examples from carbonate sequences of Sardinia (Cambrian) and Tuscany (Triassic-Jurassic), Italy: an analogous tectono-sedimentary and climatic context

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cocozza, T.; Gandin, A.

Lower Cambrian Ceroide Limestone (Sardinia) and Lower Jurassic Massiccio Limestone (Tuscany) belong to sequences deposited in analogous tectono-sedimentary context: the former linked to the Caledonian Sardic Phase, the latter to the Alpine Orogeny. Both units consist of massive pure limestone characterized by marginal and lagoonal sequences repeatedly interfingering in the same geological structure. This distribution indicates a morphology of the platforms composed of banks (marginal facies) and shallow basins (lagoonal facies) comparable with a Bahamian complex. Dolomitization affects patchily the massive limestone bodies, and karstic features, breccias, and sedimentary dikes occur at their upper boundary. Both units overlie early dolomitemore » and evaporites (sabkha facies) containing siliciclastic intercalations in their lower and/or upper part and are unconformably covered by open-shelf red (hematitic), nodular limestone Ammonitico Rosso facies). The sedimentary evolution of the two sequences appears to have been controlled by synsedimentary tectonics whose major effects are the end of the terrigenous input, the bank-and-basin morphology of the platform, the irregular distribution of the dolomitization, and the nodular fabric of the overlying facies. The end of the Bahamian-type system is marked by the karstification of the emerged blocks and is followed by their differential sinking and burial under red-nodular facies. From a geodynamic viewpoint, sequences composed of Bahamian-like platform carbonates followed by Ammonitico Rosso facies imply deposition along continental margins subjected to block-faulting during an extensional regime connected with the beginning of continental rifting. Moreover, the variation from sabkha to Bahamian conditions suggests the drifting of the continent from arid to humid, tropical areas.« less

Geology of natural gas reservoir: Upper Travis Peak Formation, western flank of Sabine Uplift, east Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fracasso, M.A.

The Travis Peak Formation (Lower Cretaceous) in the eastern East Texas basin represents a sand-rich, fluvial-deltaic depositional system. This lobate, high-constructive deltaic system prograded radially to the southeast from an Upshur County locus. Regional studies of the Travis Peak established a threefold internal stratigraphic framework: a middle sand-rich fluvial and delta-plain sequence is gradationally overlain and underlain by a marine-influenced delta-fringe zone with a higher mud content. The entire Travis Peak succession thins over the Bethany dome on the western flank of the Sabine uplift. However, the delta-fringe sequences are relatively thicker over the structure because of a disproportionately greatermore » thinning of the middle sandy fluvial-deltaic sequence. Lesser sand deposition over the Bethany dome reflects an active structural control over facies distribution. Gas production in the Bethany field and surrounding area is concentrated in thin zones (5-15 ft) of the upper delta-fringe sequence. This distribution probably reflects the increased abundance of mudstone beds in the upper delta-fringe interval, which may have served as source rocks or barriers to upward gas migration, or as both. The predominant trapping mechanism in this region is stratigraphic sand pinch-out in a structurally updip direction on the flanks of major structures. Studies of core and closely spaced electric logs west of the Bethany dome help define the depositional systems in the upper delta-fringe producing interval. This sequence comprises a complex mosaic of continental and marine facies, and exhibits an overall upward trend of increasing marine influence that spans a gradual transition into transgressive carbonates of the Sligo Formation.« less

Early Eocene biota (ostracoda, foraminifera) and paleoenvironment of the Blue Marls in the Corbieres Hills (Aude, France): building a framework for the identification of early Eocene hyperthermals in continental margin records.

NASA Astrophysics Data System (ADS)

Pirkenseer, C.; King, C.; Steurbaut, E.; Speijer, R.

2009-04-01

The Corbières Foreland Basin represents the southeastern-most extension of the Aquitanian Basin and is thus palaeo(bio)geographically related to the West-European Cenozoic Basin. During the Ypresian (‘Ilerdien') a succession of marine carbonates (e.g., Calcaires blancs à Alvéolines), marine marls (Blue Marls, Marnes à Térebratulides), brackish marls to sandstones and subsequent fluvio-lacustrine sediments (e.g., Montlaur Molasse) were deposited in the Corbières Hills (Aude, France) area in several depositional sequences. The present study focuses on the upper part of the open marine Blue Marls and the overlying brackish marls and sandstones spanning about 120m thickness close to the village Pradelles-en-Val. Over one hundred samples were collected in 1m intervals in order to document the early Eocene biogeographical and paleoenvironmental evolution of this open marine sequence, through a quantitative analysis of the ostracod assemblages. Furthermore, we aim at identifying anomalous environmental conditions that might be expected to be associated with the early Eocene hyperthermals known as Elmo- (ETM2) and X-event (ETM3). These events are subordinate to the best known hyperthermal, the Paleocene-Eocene thermal maximum, which has been recorded in deep-sea to non-marine depositional settings. ETM2 and ETM3, however, have until now only been demonstrated in deep-sea sequences, not in shelf deposits. In accordance with biostratigraphical data derived from other outcrops in the region, the sampled succession is attributed to the interval of calcareous nannofossil zones NP10-NP12. The occurrences of planktonic foraminifera of the Morozovella subbotinae-group are in agreement with this stratigraphic position (P6-7) for the lower part of the profile. Recorded fossil groups include generally abundant marine ostracoda, bryozoa, benthic and planktonic foraminifera, fragments of echinoderms including ophiuroidea, moulds of gastropods (often pyritised), large dinocysts, crab claws and few otoliths. The ostracod assemblages contain common shelf-dwelling genera, such as Acanthocythereis, Bairdoppilata, Cytherella, Echinocythereis, Eopaijenborchiella, Horrificiella, Krithe, Loxoconcha, Paracypris, Pterygocythereis throughout the section in variable numbers. Bairdoppilata and Horrificiella appear to represent the most abundant taxa. Towards the top of the section, an upward shallowing is recorded by the increase in clastic input and macrofossils sich as larger foraminifera, cerithid gastropoda and bryozoa and the disappearance of planktic foraminifera. Future work will focus on a high-resolution sampling of potential early Eocene hyperthermal events, including stable isotopic (d18O, d13C) analyses. This project is funded by the Swiss National Science Foundation (project-nr. PBFR22-116947) and further supported by the K.U.Leuven Research Fund.

The draft genome sequence and annotation of the desert woodrat Neotoma lepida.

PubMed

Campbell, Michael; Oakeson, Kelly F; Yandell, Mark; Halpert, James R; Dearing, Denise

2016-09-01

We present the de novo draft genome sequence for a vertebrate mammalian herbivore, the desert woodrat (Neotoma lepida). This species is of ecological and evolutionary interest with respect to ingestion, microbial detoxification and hepatic metabolism of toxic plant secondary compounds from the highly toxic creosote bush (Larrea tridentata) and the juniper shrub (Juniperus monosperma). The draft genome sequence and annotation have been deposited at GenBank under the accession LZPO01000000.

Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA

USGS Publications Warehouse

Elliott, J.G.; Parker, R.S.

2001-01-01

Stratigraphic and geomorphic evidence indicate floods that occur soon after forest fires have been intermittent but common events in many mountainous areas during the past several thousand years. The magnitude and recurrence of these post-fire flood events reflects the joint probability between the recurrence of fires and the recurrence of subsequent rainfall events of varying magnitude and intensity. Following the May 1996 Buffalo Creek, Colorado, forest fire, precipitation amounts and intensities that generated very little surface runoff outside of the burned area resulted in severe hillslope erosion, floods, and streambed sediment entrainment in the rugged, severely burned, 48 km2 area. These floods added sediment to many existing alluvial fans, while simultaneously incising other fans and alluvial deposits. Incision of older fans revealed multiple sequences of fluvially transported sandy gravel that grade upward into charcoal-rich, loamy horizons. We interpret these sequences to represent periods of high sediment transport and aggradation during floods, followed by intervals of quiescence and relative stability in the watershed until a subsequent fire occurred. An alluvial sequence near the mouth of a tributary draining a 0??82 km2 area indicated several previous post-fire flood cycles in the watershed. Dendrochronologic and radiocarbon ages of material in this deposit span approximately 2900 years, and define three aggradational periods. The three general aggradational periods are separated by intervals of approximately nine to ten centuries and reflect a 'millennium-scale' geomorphic response to a closely timed sequence of events: severe and intense, watershed-scale, stand-replacing fires and subsequent rainstorms and flooding. Millennium-scale aggradational units at the study site may have resulted from a scenario in which the initial runoff from the burned watershed transported and deposited large volumes of sediment on downstream alluvial surfaces and tributary fans. Subsequent storm runoff may have produced localized incision and channelization, preventing additional vertical aggradation on the sampled alluvial deposit for several centuries. Two of the millennium-scale aggradational periods at the study site consist of multiple gravel and loam sequences with similar radiocarbon ages. These closely dated sequences may reflect a 'multidecade-scale' geomorphic response to more frequent, but aerially limited and less severe fires, followed by rainstorms of relatively common recurrence. Published in 2001 by John Wiley and Sons, Ltd.

WikiGenomes: an open web application for community consumption and curation of gene annotation data in Wikidata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Putman, Tim E.; Lelong, Sebastien; Burgstaller-Muehlbacher, Sebastian

With the advancement of genome-sequencing technologies, new genomes are being sequenced daily. Although these sequences are deposited in publicly available data warehouses, their functional and genomic annotations (beyond genes which are predicted automatically) mostly reside in the text of primary publications. Professional curators are hard at work extracting those annotations from the literature for the most studied organisms and depositing them in structured databases. However, the resources don’t exist to fund the comprehensive curation of the thousands of newly sequenced organisms in this manner. Here, we describe WikiGenomes (wikigenomes.org), a web application that facilitates the consumption and curation of genomicmore » data by the entire scientific community. WikiGenomes is based on Wikidata, an openly editable knowledge graph with the goal of aggregating published knowledge into a free and open database. WikiGenomes empowers the individual genomic researcher to contribute their expertise to the curation effort and integrates the knowledge into Wikidata, enabling it to be accessed by anyone without restriction.« less

WikiGenomes: an open web application for community consumption and curation of gene annotation data in Wikidata

DOE PAGES

Putman, Tim E.; Lelong, Sebastien; Burgstaller-Muehlbacher, Sebastian; ...

2017-03-06

With the advancement of genome-sequencing technologies, new genomes are being sequenced daily. Although these sequences are deposited in publicly available data warehouses, their functional and genomic annotations (beyond genes which are predicted automatically) mostly reside in the text of primary publications. Professional curators are hard at work extracting those annotations from the literature for the most studied organisms and depositing them in structured databases. However, the resources don’t exist to fund the comprehensive curation of the thousands of newly sequenced organisms in this manner. Here, we describe WikiGenomes (wikigenomes.org), a web application that facilitates the consumption and curation of genomicmore » data by the entire scientific community. WikiGenomes is based on Wikidata, an openly editable knowledge graph with the goal of aggregating published knowledge into a free and open database. WikiGenomes empowers the individual genomic researcher to contribute their expertise to the curation effort and integrates the knowledge into Wikidata, enabling it to be accessed by anyone without restriction.« less

Neural correlates of nesting behavior in zebra finches (Taeniopygia guttata).

PubMed

Hall, Zachary J; Bertin, Marion; Bailey, Ida E; Meddle, Simone L; Healy, Susan D

2014-05-01

Nest building in birds involves a behavioral sequence (nest material collection and deposition in the nest) that offers a unique model for addressing how the brain sequences motor actions. In this study, we identified brain regions involved in nesting behavior in male and female zebra finches (Taeniopygia guttata). We used Fos immunohistochemistry to quantify production of the immediate early gene protein product Fos (a molecular indicator of neuronal activity) in the brain correlated this expression with the variation in nesting behavior. Using this technique, we found that neural circuitry involved in motor sequencing, social behavior, reward and motivation were active during nesting. Within pairs of nesting birds, the number of times a male picked up or deposited nesting material and the amount of time a female spent in the nest explained the variation in Fos expression in the anterior motor pathway, social behavior network, and reward neural circuits. Identification of the brain regions that are involved in nesting enables us to begin studying the roles of motor sequencing, context, and reward in construction behavior at the neural level. Copyright © 2014 Elsevier B.V. All rights reserved.

Neural correlates of nesting behavior in zebra finches (Taeniopygia guttata)

PubMed Central

Hall, Zachary J.; Bertin, Marion; Bailey, Ida E.; Meddle, Simone L.; Healy, Susan D.

2014-01-01

Nest building in birds involves a behavioral sequence (nest material collection and deposition in the nest) that offers a unique model for addressing how the brain sequences motor actions. In this study, we identified brain regions involved in nesting behavior in male and female zebra finches (Taeniopygia guttata). We used Fos immunohistochemistry to quantify production of the immediate early gene protein product Fos (a molecular indicator of neuronal activity) in the brain correlated this expression with the variation in nesting behavior. Using this technique, we found that neural circuitry involved in motor sequencing, social behavior, reward and motivation were active during nesting. Within pairs of nesting birds, the number of times a male picked up or deposited nesting material and the amount of time a female spent in the nest explained the variation in Fos expression in the anterior motor pathway, social behavior network, and reward neural circuits. Identification of the brain regions that are involved in nesting enables us to begin studying the roles of motor sequencing, context, and reward in construction behavior at the neural level. PMID:24508238

Accumulation and erosion of Mars' south polar layered deposits.

PubMed

Seu, Roberto; Phillips, Roger J; Alberti, Giovanni; Biccari, Daniela; Bonaventura, Francesco; Bortone, Marco; Calabrese, Diego; Campbell, Bruce A; Cartacci, Marco; Carter, Lynn M; Catallo, Claudio; Croce, Anna; Croci, Renato; Cutigni, Marco; Di Placido, Antonio; Dinardo, Salvatore; Federico, Costanzo; Flamini, Enrico; Fois, Franco; Frigeri, Alessandro; Fuga, Oreste; Giacomoni, Emanuele; Gim, Yonggyu; Guelfi, Mauro; Holt, John W; Kofman, Wlodek; Leuschen, Carlton J; Marinangeli, Lucia; Marras, Paolo; Masdea, Arturo; Mattei, Stefania; Mecozzi, Riccardo; Milkovich, Sarah M; Morlupi, Antonio; Mouginot, Jérémie; Orosei, Roberto; Papa, Claudio; Paternò, Tobia; Persi del Marmo, Paolo; Pettinelli, Elena; Pica, Giulia; Picardi, Giovanni; Plaut, Jeffrey J; Provenziani, Marco; Putzig, Nathaniel E; Russo, Federica; Safaeinili, Ali; Salzillo, Giuseppe; Santovito, Maria Rosaria; Smrekar, Suzanne E; Tattarletti, Barbara; Vicari, Danilo

2007-09-21

Mars' polar regions are covered with ice-rich layered deposits that potentially contain a record of climate variations. The sounding radar SHARAD on the Mars Reconnaissance Orbiter mapped detailed subsurface stratigraphy in the Promethei Lingula region of the south polar plateau, Planum Australe. Radar reflections interpreted as layers are correlated across adjacent orbits and are continuous for up to 150 kilometers along spacecraft orbital tracks. The reflectors are often separated into discrete reflector sequences, and strong echoes are seen as deep as 1 kilometer. In some cases, the sequences are dipping with respect to each other, suggesting an interdepositional period of erosion. In Australe Sulci, layers are exhumed, indicating recent erosion.

Off-platform Silurian sequences in the Ambler River quadrangle: A section in Geologic studies in Alaska by the U.S. Geological Survey during 1987

USGS Publications Warehouse

Dumoulin, Julie A.; Harris, Anita G.

1988-01-01

Lithofacies changes in coeval upper Paleozoic rocks have been used to unravel the tectonic history of northern Alaska (for example, Mayfield and others, 1983). Conodont biostratigraphy and detailed petrologic studies are now revealing facies differences in lower Paleozoic rocks that can also be used to constrain their tectono-sedimentary framework (Dumoulin and Harris, 1987). A basic element of basin analysis is the discrimination of shallow-water shelf and platform sequences from deeper water slope and basinal deposits. This report documents several new localities of deeper water, off-platform Silurian deposits in the Ambler River quadrangle and briefly outlines some of their paleogeographic implications.

Draft genome sequence of Anoxybacillus flavithermus KU2-6-11 isolated from hot-spring in Uzon caldera (Kamchatka, Russia).

PubMed

Rozanov, Aleksey S; Korzhuk, Anton V; Bryanskaya, Alla V; Peltek, Sergey E

2018-02-01

The Anoxybacillus flavithermus KU2-6-11 was isolated from sediments of a nameless hot spring. The hot spring is located in Uzon caldera (Kamchatka, Russia). The sequenced and annotated genome is 2,646,305 bp and encodes 2787genes. The draft genome sequence of the Anoxybacillus flavithermus KU2-6-11 has been deposited at DDBJ/EMBL/GenBank under the accession PEDM01000000 and the sequences could be found at the site https://www.ncbi.nlm.nih.gov/nuccore/PEDM01000000.

First-order and higher order sequence learning in specific language impairment.

PubMed

Clark, Gillian M; Lum, Jarrad A G

2017-02-01

A core claim of the procedural deficit hypothesis of specific language impairment (SLI) is that the disorder is associated with poor implicit sequence learning. This study investigated whether implicit sequence learning problems in SLI are present for first-order conditional (FOC) and higher order conditional (HOC) sequences. Twenty-five children with SLI and 27 age-matched, nonlanguage-impaired children completed 2 serial reaction time tasks. On 1 version, the sequence to be implicitly learnt comprised a FOC sequence and on the other a HOC sequence. Results showed that the SLI group learned the HOC sequence (η p ² = .285, p = .005) but not the FOC sequence (η p ² = .099, p = .118). The control group learned both sequences (FOC η p ² = .497, HOC η p 2= .465, ps < .001). The SLI group's difficulty learning the FOC sequence is consistent with the procedural deficit hypothesis. However, the study provides new evidence that multiple mechanisms may underpin the learning of FOC and HOC sequences. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Role Sequencing: Does Order Matter for Mental Health?

ERIC Educational Resources Information Center

Jackson, Pamela Braboy

2004-01-01

Role sequencing refers to the ordering of social roles. According to the normative order hypothesis, adults who follow a certain sequencing of their social roles will be better adjusted than their peers who follow other life course patterns. The normative order is defined as first entering the paid labor force, getting married, and later having…

Layered Deposits of Arabia Terra and Meridiani Planum: Keys to the Habitability of Ancient Mars

NASA Technical Reports Server (NTRS)

Allen, Carlton C.; Oehler, Dorothy Z.; Paris, Kristen N.; Venechuk, Elizabeth M.

2006-01-01

Understanding the habitability of ancient Mars is a key goal in the exploration of that planet. Evidence for conditions favorable to early life must be sought in ancient sedimentary rocks, such as those of Arabia Terra and Meridiani Planum. Arabia Terra, the northernmost extension of the ancient highlands, is dominated by cratered plains and minor ridged units. These plains extend south into the adjacent Meridiani Planum. The Opportunity rover landed in northern Meridiani, close to the border with Arabia. High resolution MOC images reveal extensive layered sequences across much of the Arabia and Meridiani region. These layers have been interpreted as eroded remnants of sedimentary rock deposits (Edgett, 2005). The layered sequences are concentrated in the SW quadrant of Arabia and in northern Meridiani. Preliminary mapping by Edgett (2005) distinguished four large scale layered sequences in the Arabia and Meridiani region. These have dimensions of hundreds to more than 1,000 km. MOLA altimetry shows that each of the sequences can attain a thickness of 200 to 400 m, with a total thickness greater than 1 km. The sequences are generally flat lying, with regional slopes of a few degrees. Much finer layering is evident within a number of craters. The plains and ridged units of the Arabia and Meridiani region were originally mapped as Noachian based on crater statistics, particularly the number of large craters (Scott and Carr, 1978). The layered sequences in the current study postdate many, but not all, of these large craters. The layered sequences have partially or totally filled a number of craters with diameters ranging from 20 to over 50 km. The topmost layered sequence, as well as the lower two sequences, have intermediate thermal inertia, as derived from THEMIS, indicative of moderate induration. The TES spectra from the lower sequences include features indicative of basalt. Some areas of the topmost sequence, which includes the Opportunity landing site, have TES spectra dominated by hematite. Just below this topmost sequence lies a sequence with higher thermal inertia, indicative of more indurated or coarser grained material. The TES spectra of this sequence lack distinctive mineral features, and the rocks may be obscured by a thin coating of dust. The layers have been extensively eroded. The uppermost sequences are characterized by deeply scalloped boundaries. Filled craters have been partially exhumed. Finely layered deposits within craters have been strongly dissected. Landforms uniquely attributable to wind erosion are rare, but erosive styles and geomorphology characteristic of water and possibly ice are present. The layered sequences in Arabia Terra and Meridiani Planum likely reflect an epoch when the planet was much more habitable than it is today. Several areas in these layered sequences are under intensive study as candidate landing sites for the 2009 Mars Science Laboratory.