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Sample records for south caspian basin

  1. Tectonic History and Modelling of South Caspian Basin

    NASA Astrophysics Data System (ADS)

    Korotaev, M.; Nikishin, A.; Ershov, A.; Brunet, M.-F.

    South Caspian Basin is situated to the east from Caucasus mountains, to the north from Alborz mountain and to the west from Turkmenia. Basin is underlyed by oceanic crust and has extremely high thickness of sediments - up to 22 km. Generally, sedi- ments of South Caspian are divided in 9 complexes (by seismic data): from Jurassic to Quaternary, mostly terrigenous sediments. Modern stress fields obtained from struc- tural data, earthquakes data and GPS data shows compressional environments in South Caspian Region. We propose that the South Caspian Basin was opened in Callovian- Late Jurassic. Callovian-Late Jurassic rapid subsidence event is well documented for the Pre-Caucasus area. We can conclude that a large back-arc deep water basin with very thinned to local oceanic crust originated during Callovian-Late Jurassic which in- cluded Great Caucasus Trough, South Caspian Basin and Kopet-Dagh Basin. It could be recognised the following main stages of the basin history: Callovian-Late Jurassic - that main rifting and crustal extension epoch; Cretaceous-Eocene - gentle thermal sub- sidence affected by stress events; Oligocene-Miocene - rapid subsidence with domi- nant clay deposition within the basin; Pliocene-Quaternary - unusual rapid subsidence of the South Caspian Basin coincided with mountain uplift of the Great Caucasus, Kopet-Dagh and Alborz. We made a backstripping reconstruction along the seismic profile in the central part of the south Caspian Basin. We obtained main peak of the tectonic subsidence for the South Caspian Basin in the Pliocene time - 2 km of the tectonic subsidence and tectonic subsidence rate up to 1200 m/Ma. Rapid subsidence of the basin was contemporaneous with increase of compression and orogenesis on the borders of the basin. We examine the hypothesis, explaining this rapid syncompres- sional subsidence by flexural response of the basin lithosphere to increase of imposed compressional force Lithosphere of the investigated South Caspian

  2. Anomalous wave propagation across the South Caspian Basin

    SciTech Connect

    Priestly, K.; Patton, H.J.; Schultz, C.

    1997-10-01

    The Caspian basin blocks the propagation of the regional seismic phase Lg and this has importance consequences for seismic discrimination in the Middle East. Intermediate period surface waves propagating across the basin are also severely affected. In a separate study we have developed a crustal model of the south Caspian basin and the surrounding region. The crust of the basin consists of 15-25 km of low velocity, highly attenuating sediments lying on high velocity crystalline crust. The Moho beneath the basin is at a depth of about 30 km as compared to about 50 km in the surrounding region. In this study we used an idealized rendition of this crustal model to compute hybrid normal mode finite difference synthetic seismograms to identify the features of the Caspian basin which lead to the seismic blockage. Of the various features of the basin, the thickness and attenuation of the sediments appear to be the dominant blocking mechanism.

  3. South Caspian Pliocene-Anthropogenic basin (summary of existing views)

    NASA Astrophysics Data System (ADS)

    Amrakhov, Rashad; Shiraliyeva, Sevinj; Kerimova, Nailya

    2016-04-01

    On the basis of long-time integrated sedimentology, paleogeographic and structural - formation studies covering Pliocene-Anthropogenic sediments of South Caspian Basin (SCB) and design of structural - formation, paleogeographic and catagenetic models applying geophysical studies in the region, the author has interred rift nature on this basin during Pliocene-Anthropogenic stage of its evolution. It is assumed that SCB is intercontinental with absence of continental crust. Evolution of SCR started from Miocene, continental stage of development Lesser and Great Caucasus and Kopetdag. At initial stage of South Caspian rift-graben evolution the crystal uplift of Caucasus, Kopetdag and Talysh organic system took place. Extension forces within their borders caused collapse of central part of South Caspian block. We assumed that at later stage folded blocks of Lesser Caucasus and Talysh on the other hand Alborz and Kopetdagh on the other were moving apart. As a result of these riftogene processes the contemporary structure of SCB Antropogene was formed. Starting from Miocene, subsidence of central part of SCB and later movements of folded blocks of Great and Lesser Caucasus, Talysh and Elbrus occurred along Western Caspian, Sangachal - Ogurcghy deep faults and Turkmenistan thrust. During rift generation within SCB, magmatic troughs emerged in the rift zone - South Absheron, Lower Kura. Enzaly and Western Turkmenistan. Structural-formation studies with application of geophysical data acquired in the region, allow assuming that massive Godina can be considered as interrift horst with large gravity anomaly. Its generation relates to Miocene-Pliocene ages and was formed due to South Caspian riftogenesis. The following are sedimentologic evidences of South Caspian rift basin: a) Avalanche sedimentation and development of large thickness (2.5-3 km/106 years) even within border of Lower Pliocene (Productive Series); b) Morphology of Lower Pliocene molasses formation covering 600

  4. Assessment of undiscovered oil and gas resources of the North Caspian Basin, Middle Caspian Basin, North Ustyurt Basin, and South Caspian Basin Provinces, Caspian Sea Area, 2010

    USGS Publications Warehouse

    Klett, T.R.; Schenk, Christopher J.; Charpentier, Ronald R.; Gautier, Donald L.; Brownfield, Michael E.; Pitman, Janet K.; Cook, Troy A.; Tennyson, Marilyn E.

    2010-01-01

    The U.S. Geological Survey estimated mean volumes of technically recoverable, conventional, undiscovered petroleum resources at 19.6 billion barrels of crude oil, 243 trillion cubic feet of natural gas, and 9.3 billion barrels of natural gas liquids for the Caspian Sea area, using a geology-based assessment methodology.

  5. Mitochondrial Genetic Differentiation of Spirlin (Actinopterigii: Cyprinidae) in the South Caspian Sea basin of Iran

    PubMed Central

    Seifali, Mahvash; Arshad, Aziz; Moghaddam, Faezeh Yazdani; Esmaeili, Hamid Reza; Kiabi, Bahram H.; Daud, Siti Khalijah; Aliabadian, Mansour

    2012-01-01

    Background Knowledge about Alburnoides remains lacking relative to many other species, resulting in a lack of a systematic position and taxonomic diagnosis. Basic biological information for Alburnoides has been constructed, and it is necessary to understand further and obtain more information about this species. Its phylogenetic relationships are still debated and no molecular data have been used to study this taxon in Iran. A holistic approach for genetic methods was adopted to analyze possible spirlin population differences at selected centers in the south Caspian Sea basin of Iran. Methods The phylogenetic relationships were determined based on 774 base pairs of the mitochondrial cytochrome b gene of 32 specimens of spirlin from nine locations in the south Caspian Sea drainage basin of Iran. The nucleotide sequences were subjected to phylogenetic analysis using the neighbor-joining, maximum parsimony, maximum likelihood, and Bayesian methods. Results The mitochondrial gene tree largely supports the existence of three major clades. The western populations (clade I) may be considered as Alburnoides eichwaldii, whereas the Talar river populations (clade II) are represented as Alburnoides sp.1 and the eastern populations (clade III) may be distinct taxa of Alburnoides sp.2. Conclusion This molecular evidence supports the hypothesis that A. bipunctatus does not exist in the south Caspian Sea basin of Iran, and that the western and eastern populations are distinct taxa. PMID:22654487

  6. A magnetostratigraphic time frame for Plio-Pleistocene transgressions in the South Caspian Basin, Azerbaijan

    NASA Astrophysics Data System (ADS)

    Van Baak, C. G. C.; Vasiliev, I.; Stoica, M.; Kuiper, K. F.; Forte, A. M.; Aliyeva, E.; Krijgsman, W.

    2013-04-01

    The isolation of the Caspian Sea took place in the latest Miocene coinciding with a significant lowering of sea level and the deposition of a massive lowstand deltaic system. This so-called Productive Series is the main reservoir unit of the South Caspian oil-province. The Productive Series is overlain by marine clays from the Akchagylian and Apsheronian regional stages. During the Plio-Pleistocene, the Caspian basin experienced several short periods of intermittent connectivity with other marine basins. This work aims to create integrated, high-resolution, bio-magnetostratigraphic dating of these regional transgressions in key sections of the South Caspian Basin in Azerbaijan. We sample two long sections, the Lokbatan section in the Palaeo-Volga delta and the Xocashen section in the Kura Basin. Palaeoenvironmental reconstructions are derived from characteristic ostracod species. Rock magnetic analyses combined with thermal demagnetisation data indicate that the magnetic signal is carried dominantly by the iron oxide magnetite in the Productive Series of Lokbatan section and in the Xocashen section. The marine Akchagylian and Apsheronian of Lokbatan are characterised by the iron sulphide greigite, which appears to be of (near-) primary origin. The most logical correlation of the magnetic polarity patterns to the Geomagnetic Polarity Time Scale dates the Akchagylian transgression at ~ 3.2 Ma, a major transgression during the Apsheronian at ~ 2.0 Ma and the Bakunian transgression at 0.85-0.89 Ma. Ostracod assemblages indicate increasing salinities during these transgressions, from fresh water lacustrine to brackish-marine species. This implies that marine connections have been created with an adjacent basin that has a higher salinity, most likely the Black Sea.

  7. Imaging lithospheric structure in northern Scotland and the South Caspian Basin

    NASA Astrophysics Data System (ADS)

    Asencio, Eugenio

    Passive- and active-source seismological studies of northern Scotland and the South Caspian Basin indicate: (1) pervasive and laterally heterogeneous velocity discontinuities within the upper mantle influenced by the localized tectonic and thermal history of northwest Scotland, and (2) growth fault-bend folds overriding a regional ductile detachment zone at a depth of about 13 to 16 km in response to a component of right-lateral simple shear of the underlying crust between the South Caspian Basin and the central and western Caucasus. Teleseismic earthquakes recorded by a small array of portable broadband stations and permanent short-period stations are used to ascertain the lateral extent of velocity discontinuities within the continental mantle lithosphere beneath Scotland. Radial receiver functions contain distinct P-to-S ( Ps) converted phases at about 3.1--3.2 s and at 4.5--5.2 s after the direct P-wave. These observations suggest that the upper mantle Ps phase originates from a high velocity and/or anisotropic layer within the upper mantle. At two stations, ORE and BACA, located along the northern shoreline of Scotland, these upper mantle phases can be correlated with the W-reflector, a bright, regionally extensive seismic reflector previously observed on marine deep seismic reflection and wide-angle refraction-reflection profiles. However, the variability in physical characteristics suggests the possibility that there may be multiple layered reflectors in the upper mantle beneath northern Scotland and revives debates on the regional and global significance of upper mantle layering. Deep seismic reflection profiles acquired in the deepwater of the South Caspian Sea, offshore Azerbaijan image a thick sequence of sediments (19--22 km thick) that structurally have been deformed into relatively symmetrical folds. These structures are interpreted as fault-bend growth folds overriding a regional ductile detachment zone at a depth of about 13 to 16 km. The analysis

  8. Structural evolution of the Kopet Dagh fold-and-thrust belt (North-East Iran) and interactions with the South Caspian Sea Basin and Amu Darya Basin

    NASA Astrophysics Data System (ADS)

    Robert, Alexandra M. M.; Letouzey, Jean; Kavoosi, Mohammad A.; Sherkati, Sharham; Müller, Carla; Vergés, Jaume

    2014-05-01

    We present a detailed stratigraphic and structural study of the Kopet Dagh fold-and-thrust belt in NE Iran, which is an investigation of the complex polyphased tectonic history of this belt and its links with the adjacent South Caspian Sea and Amu Darya basins. Based on numerous field surveys, a large amount of 2D and 3D seismic data, borehole data and more than 150 new biostratigaphic datings, a new detailed biostratigraphic chart and 4 main regional cross-sections illustrate the importance of lateral facies variations and structural inheritance in the present-day structure of the belt. After the Cimmerian orogeny corresponding to the closure of the Paleotethys Ocean in Late Triassic-Early Jurassic times, a post-collisional rifting event was associated with the deposition of one of the main source rocks of the Kopet Dagh and the Amu Darya Basin (Kashafrud Formation). Following this rifting event, over 7 km of sediments were accumulated until the Tertiary above a regional post-Triassic unconformity. The occurrence of local uplifts during the Late Cretaceous-Early Paleocene is interpreted as a consequence of regional-scale modification of plate-slab coupling in the Neotethys subduction zone. The structures associated with the Late Eocene/Oligocene folding phase are sealed in the western part of the belt by a major Eocene-Oligocene unconformity at the base of the thick sedimentary series belonging to the South Caspian Sea Basin. The rapid subsidence of the South Caspian Sea Basin is probably related to syn-compressional downward flexure of the resistant basement basin at the onset of the Alpine phase. In the eastern part of the Kopet Dagh, this deformation is characterized by Middle Jurassic graben inversion with evidences of forced-folding, short-cuts and present-day slip partitioning, and as well by larger scale basement uplift. In contrast, the northwestern part of the belt shows thrust faults involving basement and fault-propagation folds within the sedimentary

  9. Modeling anomalous surface - wave propagation across the Southern Caspian basin

    SciTech Connect

    Priestly, K.F.; Patton, H.J.; Schultz, C.A.

    1998-01-09

    The crust of the south Caspian basin consists of 15-25 km of low velocity, highly attenuating sediment overlying high velocity crystalline crust. The Moho depth beneath the basin is about 30 km as compared to about 50 km in the surrounding region. Preliminary modeling of the phase velocity curves shows that this thick sediments of the south Caspian basin are also under-lain by a 30-35 km thick crystalline crust and not by typical oceanic crust. This analysis also suggest that if the effect of the over-pressuring of the sediments is to reduce Poissons` ratio, the over-pressured sediments observed to approximately 5 km do not persist to great depths. It has been shown since 1960`s that the south Caspian basin blocks the regional phase Lg. Intermediate frequency (0.02-0.04 Hz) fundamental mode Raleigh waves propagating across the basin are also severely attenuated, but the low frequency surface waves are largely unaffected. This attenuation is observed along the both east-to-west and west-to-east great circle paths across the basin, and therefore it cannot be related to a seismograph site effect. We have modeled the response of surface waves in an idealized rendition of the south Caspian basin model using a hybrid normal mode / 2-D finite difference approach. To gain insight into the features of the basin which cause the anomalous surface wave propagation, we have varied parameters of the basin model and computed synthetic record sections to compare with the observed seismograms. We varied the amount of mantel up-warp, the shape of the boundaries, the thickness and shear wave Q of the sediments and mantle, and the depth of the water layer. Of these parameters, the intermediate frequency surface waves are most severely affected by the sediments thickness and shear wave attenuation. fundamental mode Raleigh wave phase velocities measure for paths crossing the basin are extremely low.

  10. The Lower Jurassic of the Eastern Caspian region and the Middle Caspian Basin: Lithology, facies, taphonomy

    NASA Astrophysics Data System (ADS)

    Kiritchkova, A. I.; Nosova, N. V.

    2014-09-01

    Lithofacies of the productive Upper Triassic-Lower Jurassic deposits of the Eastern Caspian region, studied in wells on the Caspian coast and exposed in the outcrops of the Mountainous Mangyshlak, are described and analyzed. The similarity of the structure of the Mesozoic sedimentary beds of the Middle Caspian Basin and of those of the land adjacent to its eastern coast is confirmed. Comparative analysis of lithofacies allowed the reconstruction of the paleogeographic setting and depositional environments in the studied region during the Early Jurassic. A unique fossil plant occurrence is discovered in the upper part of the Lower Jurassic series (in the lower subformation of the Kokala Formation; Eastern Caspian region). Fossil plant taphonomy and the lithology of host rocks in the occurrence resulted from unusual paleogeographic settings that existed in the Middle Caspian Basin at the time of the Early-Middle Jurassic boundary.

  11. From the Allerød to the mid-Holocene: palynological evidence from the south basin of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Leroy, Suzanne A. G.; Tudryn, Alina; Chalié, Françoise; López-Merino, Lourdes; Gasse, Françoise

    2013-10-01

    Pollen and dinoflagellate cysts have been analysed in a core from the south basin of the Caspian Sea, providing a picture of respectively past vegetation and water salinity for the Late Pleistocene to middle Holocene. A relatively sharp lithological change at 0.86 m depth reflects a shift from detrital silts to carbonates-rich fine silts. From this depth upwards, a Holocene chronology is built based on ten radiocarbon dates on ostracod shells and bulk carbonates. From the vegetation point of view, the Late Pleistocene deserts and steppes were partially replaced in the most sheltered areas by an open woodland with Pinus, Juniperus-Hippophae-Elaeagnus and even Alnus-Quercus-Pterocarya and Fraxinus, related to the Allerød palynozone. This was interrupted by the Younger Dryas palynozone when Artemisia reaches a maximum in a first instance followed by a very dry phase with only a slight return of Pinus and Quercus and the rare presence of Ulmus-Zelkova. From 11.5 to 8.4 cal. ka BP, an open landscape dominated by shrubs such as Ephedra and progressively increasing Quercus appeared. The final spread of diverse evergreen and deciduous trees is delayed and occurs after 8.4 cal. ka BP. It is suggested that this delay is caused by an arid climate in the Early Holocene linked to high insolation and perhaps to a lake effect. The dinocyst assemblages fluctuate between slightly brackish (Pyxidinopsis psilata and Spiniferites cruciformis, 7 psu and lower) and more brackish (Impagidinium caspienense, ˜13 psu). In the Lateglacial (Khvalynian highstand), the assemblages remained dominated by relative low salinity taxa. A late and brief increase of salinity occurred prior to 11.2 cal. ka BP associated with the Mangyshlak lowstand. It is suggested that it was caused by a brief drop in meltwater flow from both the north and the southeast (Uzboy) and a likely evaporation increase. This lowstand occurs quasi at the same time as the end of a longer lowstand in the Black Sea. The freshest

  12. Interpretation of fault-controlled ramp structures in sedimentary basins - example from Caspian Sea using Landsat TM data

    SciTech Connect

    Iranpanah, A.

    1989-03-01

    Lineaments on a series of edge-enhanced images (TM data) from a region around the Caspian Sea form a geomorphically significant linear trend along the major Caucasus-Kopeh Dagh fault line. This fault represents the line of collision between the Cimmerian continents and the Turan plate on the south and north, respectively. The lineament zone manifests a ramp structure that forms a relatively narrow topographic high in the Caspian Sea. Paleogeographic studies of the Caspian Sea suggest that the basin is part of the eastern Paratethys, which began to develop in the early Paleogene during the Alpine-Himalayan uplift. On the basis of the lineaments and associated geomorphic features, the Caspian Sea can be divided into southern, central, and the northern Caspian subbasins. The Caucasus-Kopeh Dagh fault line trends N80/degrees/W and separates the southern Caspian from the central subbasin, approximately along 40/degrees/N latitude. The boundary between the central and the northern subbasins is also a linear topographic high which trends N70/degrees/E and lies approximately at 44/degrees/N latitude. The southern and central subbasins have subequal areal extension covering 35.64% and the 36.63% of the whole sea, whereas the northern subbasin occupies only 27.73% of the basin.

  13. Mud Volcanism in the South East Caspian, Gorgon Plane, Iran

    NASA Astrophysics Data System (ADS)

    Mazzini, A.; Poludetkina, E. N.; Mehrabi, B.; Krueger, M.; Inguaggiato, S.; Etiope, G.

    2014-12-01

    Although numerous studies have been completed on the Western Caspian side (e.g. mainly Azerbaijan), very little is known about the hydrocarbon plumbing system of the deepest and southernmost basin. This region has great potentials for hydrocarbon exploration and the study of mud volcanoes located here represents the opportunity to access to an open window to better understand the stratigraphy and the mechanisms ongoing at great depth as well as the origin and signature of the seeping fluids. Three so far unexplored mud volcano structures (Sofikam, Gharniarigh, and Naftliche) have been mapped and sampled in the Golestan region in the south eastern Caspian Sea. All the structures have negative morphology (i.e. "pockmark like") with caldera collapse. A multidisciplinary workflow of analyses is being conducted including gas and water geochemistry, incubation of microbial colonies, petrography of the seeping mud and erupted mud breccia clasts. Sofikam consists of 5 distinct pools up to 4-5 m in diameter that forms an E-W oriented alignment. All of the pools display vigorous seepage of fluids and are either water- or denser mud-dominated. Gharniarigh is a large mud volcano up to ~600 m in diameter with a bulging island in the internal part of the crater where eroded gryphons ridges witness a palaeo vigorous activity. The outskirts of the "island" are almost entirely flooded with water and/or covered with salt crusts in the summer. Here are distributed several small water and gas seeps. Naftliche (~400 m wide) is filled with water with a main seep in the centre of the lake. Preliminary gas geochemistry indicates the seepage of methane-dominated gas in all structures with additional small portions of ethane and propane as well as iC4 in Gharniarigh and Naftliche. All samples collected for microbial colonies incubation reveal strong activity with CO2 production under aerobic and anaerobic conditions as well as production of biogenic methane. In particular, samples from

  14. Petroleum geology and resources of the middle Caspian Basin, Former Soviet Union

    USGS Publications Warehouse

    Ulmishek, Gregory F.

    2001-01-01

    The Middle Caspian basin occupies a large area between the Great Caucasus foldbelt and the southern edge of the Precambrian Russian craton. The basin also includes the central part of the Caspian Sea and the South Mangyshlak subbasin east of the sea. The basin was formed on the Hercynian accreted terrane during Late Permian?Triassic through Quaternary time. Structurally, the basin consists of the fold-and-thrust zone of the northern Caucasus foothills, the foredeep and foreland slope, the Stavropol-Prikumsk uplift and East Manych trough to the north of the slope, and the South Mangyshlak subbasin and slope of the Karabogaz arch east of the Caspian Sea. All these major structures extend offshore. Four total petroleum systems (TPS) have been identified in the basin. The South Mangyshlak TPS contains more than 40 discovered fields. The principal reserves are in Lower?Middle Jurassic sandstone reservoirs in structural traps. Source rocks are poorly known, but geologic data indicate that they are in the Triassic taphrogenic sequence. Migration of oil and gas significantly postdated maturation of source rocks and was related to faulting and fracturing during middle Miocene to present time. A single assessment unit covers the entire TPS. Largest undiscovered resources of this assessment unit are expected in the largely undrilled offshore portion of the TPS, especially on the western plunge of the Mangyshlak meganticline. The Terek-Caspian TPS occupies the fold-and-thrust belt, foredeep, and adjoining foreland slope. About 50 hydrocarbon fields, primarily oil, have been discovered in the TPS. Almost all hydrocarbon reserves are in faulted structural traps related to thrusting of the foldbelt, and most traps are in frontal edges of the thrust sheets. The traps are further complicated by plastic deformation of Upper Jurassic salt and Maykop series (Oligocene? lower Miocene) shale. Principal reservoirs are fractured Upper Cretaceous carbonates and middle Miocene sandstones

  15. Petroleum geology and resources of the North Caspian Basin, Kazakhstan and Russia

    USGS Publications Warehouse

    Ulmishek, Gregory F.

    2001-01-01

    The North Caspian basin is a petroleum-rich but lightly explored basin located in Kazakhstan and Russia. It occupies the shallow northern portion of the Caspian Sea and a large plain to the north of the sea between the Volga and Ural Rivers and farther east to the Mugodzhary Highland, which is the southern continuation of the Ural foldbelt. The basin is bounded by the Paleozoic carbonate platform of the Volga-Ural province to the north and west and by the Ural, South Emba, and Karpinsky Hercynian foldbelts to the east and south. The basin was originated by pre-Late Devonian rifting and subsequent spreading that opened the oceanic crust, but the precise time of these tectonic events is not known. The sedimentary succession of the basin is more than 20 km thick in the central areas. The drilled Upper Devonian to Tertiary part of this succession includes a prominent thick Kungurian (uppermost Lower Permian) salt formation that separates strata into the subsalt and suprasalt sequences and played an important role in the formation of oil and gas fields. Shallow-shelf carbonate formations that contain various reefs and alternate with clastic wedges compose the subsalt sequence on the 1 basin margins. Basinward, these rocks grade into deep-water anoxic black shales and turbidites. The Kungurian salt formation is strongly deformed into domes and intervening depressions. The most active halokinesis occurred during Late Permian?Triassic time, but growth of salt domes continued later and some of them are exposed on the present-day surface. The suprasalt sequence is mostly composed of clastic rocks that are several kilometers thick in depressions between salt domes. A single total petroleum system is defined in the North Caspian basin. Discovered reserves are about 19.7 billion barrels of oil and natural gas liquids and 157 trillion cubic feet of gas. Much of the reserves are concentrated in the supergiant Tengiz, Karachaganak, and Astrakhan fields. A recent new oil discovery

  16. Microseismicity and seismotectonics of the South Caspian Lowlands, NE Iran

    NASA Astrophysics Data System (ADS)

    Nemati, Majid; Hollingsworth, James; Zhan, Zhongwen; Bolourchi, Mohammad Javad; Talebian, Morteza

    2013-06-01

    This paper is concerned with the microseismicity and seismotectonics of the eastern South Caspian Sea region, where the East Alborz mountains descend to meet the South Caspian Lowlands of NE Iran. To better understand the present-day tectonics and seismicity of this region, which includes the cities of Gorgan and Gonbad-e-Qabus (combined population 500 000), we installed a temporary local seismic network across the area for 6 months between 2009 and 2010. We analysed the seismicity and focal mechanisms together with data from the permanent networks of the Institute of Geophysics, University of Tehran (IGUT) and the International Institute of Earthquake Engineering and Seismology (IIEES), based in Tehran. Microseismicity is focused primarily on the Shahrud fault system, which bounds the east Alborz range to the south. Relatively few earthquakes are associated with the Khazar thrust fault, which bounds the north side of the range. A cluster of shallow microseismicity (<15 km depth) occurs 40 km north of the Khazar fault (within the South Caspian Lowlands; SCL), an area typically thought to be non-deforming. This area coincides with the location of three relatively deep thrust earthquakes (Mw 5.3-5.5) which occurred in 1999, 2004 and 2005. Inversion of teleseismic body waveforms allows us to constrain the depth of these earthquakes at 26-29 km. Although significant sedimentation throughout the SCL obscures any expression of recent fault activity at the surface, focal mechanisms of well-located events from the shallow cluster of micro-seismicity show a significant component of left-lateral strike-slip motion (assuming slip occurs on NE-SW fault planes, typical of active faults in the region), as well as a small normal component. Inversion of traveltimes for well-located events in our network yields a velocity structure for the region, and a Moho depth of 41 km. The pattern of deep thrust and shallow normal seismicity could be explained by bending of the rigid South

  17. Genetic variation among agamid lizards of the trapelus agiliscomplex in the caspian-aral basin

    SciTech Connect

    Macey, J. Robert; Ananjeva, Natalia B.

    2004-05-19

    Allozyme variation is examined in eight populations of Trapelus from the Caspian-Aral Basin of the former USSR. Thirty-one loci (15 variable) exhibit remarkably low levels of genetic variation with only a Nei's genetic distance of 0.117 across 2500 km. An isolated population on the European side of the Caspian Sea is found to phenetically cluster inside the Asian populations examined, suggesting that it should not be considered taxonomically distinct.

  18. Special features of the hydrochemical conditions variability in the deep water basins of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Serebrennikova, E. A.; Sapozhnikov, V. V.; Dukhova, L. A.

    2015-03-01

    The features of the long-term variability of the hydrochemical characteristics of deep-water basins of the Caspian Sea are studied on the basis of information obtained during 18- year annual monitoring and supplemented with historical data. The effect of hypoxia and the hydrogen sulfide layer on the position of the nitrate-maximum layer and the content of nitrates in it are shown. Studying the variability of the vertical distribution of the hydrochemical indicators revealed several factors that determine the removal of nutrients from the photic layer and their accumulation in the bottom layer. Among other things, the latest data revealed the unique features of the Caspian coastal upwelling. This will help to avoid underestimation of the productivity of the waters in the Middle Caspian Basin.

  19. Terrestrial outdoor exposures in the south-west Caspian region.

    PubMed

    Khoshbinfar, S; Vahabi Moghaddam, M

    2010-12-01

    Natural radionuclides (40)K, (232)Th and (238)U present in soil and anthropogenic (137)Cs a fission product released to the environment mainly through atmospheric testing of nuclear arms and accidents in nuclear installations are the major contributors to terrestrial outdoor exposures. As part of a comprehensive study of environmental radioactivity in the south Caspian region, soil inventories of these radionuclides have been measured in more than 50 locations throughout Guilan, a northern province of Iran with the highest population density. In the case of natural radionuclides, outdoor absorbed dose rates in air have been inferred from concentrations of radionuclides in soil on the basis of which annual effective dose values have been estimated using the method described in UNSCEAR 2000. Calculation of (137)Cs contribution to dose has been performed by considering its soil inventory profiles and associated numerically estimated photon fluxes at 1 m above the ground. Maps representing the contribution of natural and anthropogenic radionuclides to annual effective dose in the study area have been produced using relevant geostatistical technique. Combined annual effective dose equivalent ranges from 33.1 ± 4.9 to 91.9 ± 16.5 μSv · y(-1) with a mean value of 64.7 ± 15.2 μSv · y(-1).

  20. Satellite Observation of Large Scale Changes in Climate and Land Use in the Caspian Sea Basin

    NASA Astrophysics Data System (ADS)

    Saatchi, S.; Nouri, A.; Asefi, S.; Shiklomanov, A.; Entekhabi, D.; Mohammadi, S.; Hedjazi, B.

    2012-04-01

    The Caspian Sea Basin (catchments) area occupies the vast European and Asian territory between approx. 330-580 N latitude and 300-620 E longitude. In comparison with other world great natural lakes, the Caspian Sea ranks first in watershed area (3660,000 km2) and also in a total annual rivers runoff (340 km3/year - long-term average value). The Caspian is a closed basin with the largest landlocked water body in the world in its center. As a result, the water and biogeochemical cycles over the sea and surrounding lands are intimately linked. Any changes in the hydrologic regime over land and any major shifts in land use and land ecosystem health will directly impact the overall water and energy cycle of the basin, as well as the water quality and aquatic biology of the Sea. The basin being a closed system, it can also exhibit feedback processes that reinforce excursions from normal and lead to large impacts on the surrounding regions. In this paper, we present results of the analysis of climate and vegetation observations over the past 30 years over the Caspian Sea Basin to document the changes of climate, and land use, the regional vegetation response. We focus our analysis using data from AVHRR, MODIS, QSCAT, and TRMM. The results indicate that the region has gone through major changes in land use accompanied by anomalies of temperature and rainfall that in turn has suppressed the vegetation cover and phenology. The results are corroborated by data from socio-economic changes in the region and ground observation of climate and vegetation.

  1. The Ponto-Caspian basin as a final trap for southeastern Scandinavian Ice-Sheet meltwater

    NASA Astrophysics Data System (ADS)

    Tudryn, Alina; Leroy, Suzanne A. G.; Toucanne, Samuel; Gibert-Brunet, Elisabeth; Tucholka, Piotr; Lavrushin, Yuri A.; Dufaure, Olivier; Miska, Serge; Bayon, Germain

    2016-09-01

    This paper provides new data on the evolution of the Caspian Sea and Black Sea from the Last Glacial Maximum until ca. 12 cal kyr BP. We present new analyses (clay mineralogy, grain-size, Nd isotopes and pollen) applied to sediments from the river terraces in the lower Volga, from the middle Caspian Sea and from the western part of the Black Sea. The results show that during the last deglaciation, the Ponto-Caspian basin collected meltwater and fine-grained sediment from the southern margin of the Scandinavian Ice Sheet (SIS) via the Dniepr and Volga Rivers. It induced the deposition of characteristic red-brownish/chocolate-coloured illite-rich sediments (Red Layers in the Black Sea and Chocolate Clays in the Caspian Sea) that originated from the Baltic Shield area according to Nd data. This general evolution, common to both seas was nevertheless differentiated over time due to the specificities of their catchment areas and due to the movement of the southern margin of the SIS. Our results indicate that in the eastern part of the East European Plain, the meltwater from the SIS margin supplied the Caspian Sea during the deglaciation until ∼13.8 cal kyr BP, and possibly from the LGM. That led to the Early Khvalynian transgressive stage(s) and Chocolate Clays deposition in the now-emerged northern flat part of the Caspian Sea (river terraces in the modern lower Volga) and in its middle basin. In the western part of the East European Plain, our results confirm the release of meltwater from the SIS margin into the Black Sea that occurred between 17.2 and 15.7 cal kyr BP, as previously proposed. Indeed, recent findings concerning the evolution of the southern margin of the SIS and the Black Sea, show that during the last deglaciation, occurred a westward release of meltwater into the North Atlantic (between ca. 20 and 16.7 cal kyr BP), and a southward one into the Black Sea (between 17.2 and 15.7 cal kyr BP). After the Red Layers/Chocolate Clays deposition in both seas

  2. Structural development and petroleum potential of the Dagestan foreland thrust belt, Terek-Caspian Basin, Russia

    SciTech Connect

    Sobornov, K. )

    1994-07-01

    The Dagestan foreland thrust belt represents a transition zone between the Terek-Caspian basin and Caucasus. Boreholes and seismic data obtained during the last decade in the course of petroleum exploration reveal considerable differences between the surface and subsurface structures of the area. The new data suggest that the allochthonous assemblage of the belt is formed mainly by stacked north-verging thrust sheets made up mostly of Mesozoic carbonates and sandstones bounded at the top and bottom by conjugate detachment surfaces. The thrust sheets are interpreted to be inserted into the clastic section of the Terek-Caspian foredeep along the base of Oligocene-early Miocene mudstones. The interpreted geometry of the thrust-belt front implies a shortening of about 20-50 km. The blind subsurface thrusts have been active since late Miocene and Holocene. The interpreted structural relationships between Mesozoic-Cenozoic stratigraphic units imply that principal thrusts were formed due to reactivation and inversion of low-angle normal faults, which were active in the Jurassic - early Miocene. Mechanical weakness and low density of the overpressured Oligocene - lower Miocene Maykop Formation aided subsurface thrusting. The new interpretation of the regional structure offers a petroleum exploration play consisting of structural traps within the buried antiformal stacks. Oil- and gas-bearing Upper Cretaceous and Upper Jurassic carbonate rocks involved in thrust sheets are considered primary prospecting targets.

  3. The Caspian megabasin: tectonics and evolution

    NASA Astrophysics Data System (ADS)

    Khain, V. E.; Bogdanov, N. A.

    2003-04-01

    The Caspian Sea occupies at longitudinally elongated depression, superimposed in the latest Miocene on different structural units, oriented in WNW-ESE direction and belonging to the southern edge of the East European Craton and to the Mediterranean mobile belt. The Caspian megabasin comprises three basins - Northern, Middle and Southern with different age of basement and sedimentary fill, structural style and recent tectonics. The evolution of the whole region could be followed from Neoproterozoic onwards. At that epoch, an oceanic basin-Prototethys appeared after the breakup of Rodinia between Baltica and Gondwana. Its volcano-sedimentary sequence outcrops in the Greater Caucasus and Dzirula massif in Transcaucasia. After the Baikalian (=Cadomian/Panafrican) orogeny the central and southern part of the region was cratonised and formed the northern rim of Gondwana, presumably separated from Baltica by a relic of Prototethys. In Ordovician two branches of the Paleotethys crossed the region - the northern passed through the Greater Caucasus, the southern through Talesh; they were separated by the Transcaucasian microcontinent. At the southern edge of Baltica the Donets-Karpinsky Ridge rift system was formed in mid-Devonian. The northern branch of the Paleotethys was severely deformed, intruded by granites and metamorphosed by the Hercynian orogeny; only a remnant marine basin persisted to the south of the orogen. It was deformed in its tour, along with the southern-Paleotethys branch by the Eocimmerian orogeny which also caused the final inversion of the Donets-Karpinsky rift system. After these events the Fore-Caucasus region became the young Scythian platform - part of the Eurasian continent. In the Early Jurassic rifting opened the Greater Caucasus basin, marginal in respect to the Neotethys, one of the main branch of which passed through the Lesser Caucasus and probably along the southern border of the Alborz Range, separating it from the Iranian microcontinent

  4. Trace element concentrations in feathers of five Anseriformes in the south of the Caspian Sea, Iran.

    PubMed

    Karimi, Mohammad-Hosein Sinka; Hassanpour, Mehdi; Pourkhabbaz, Ali-Reza; Błaszczyk, Martyna; Paluch, Joanna; Binkowski, Łukasz J

    2016-01-01

    Birds are susceptible to environmental changes, which make them particularly important as indicators of environmental contamination, including metal concentrations. In the present study, the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) in the tail and flight feathers of greylag goose, mallard, pintail, pochard, and wigeon were investigated from the south of the Caspian Sea in Iran by the electrothermal atomic absorption spectrometry (ET-AAS) method. The trend of metal concentrations in both types of feathers of all the examined species was as follows: Fe < Zn < Mn < Cd ∼ Cr ∼ Ni ∼ Pb < As. The interspecies variation in concentrations of almost all the studied metals was observed, as well as the significant differences between feather types. The only exception was Ni, the medians of which were comparable in tail and primaries. Correlations of concentrations of Cd, Mn, Ni, Pb, and Zn in primaries and tail feathers were positive and statistically significant. Elevated concentrations of Cd, Cr, Mn, and Pb were noted so the possibility of environmental contamination of the area is suspected.

  5. Use of leisure time in cardiovascular patients in Gorgan (south east of Caspian Sea).

    PubMed

    Marjani, A; Ramazani, M A; Khori, V; Jamshir, M; Alizadeh, F

    2009-01-01

    The aim of this study was to compare activity patterns and leisure time between matched groups of patients with cardiovascular disease and individuals without a heart disease. The study included 100 patients recruited from those referred to cardiology department of 5th Azar General Hospital of Golestan University of Medical Sciences in Gorgan (South East of Caspian Sea) and 100 matched control subjects during the period 2007-2008. Odds ratios (OR), together with 95% confidence intervals (95% CI), were calculated using logistic regression, as estimates of relative risks. Listening to music OR = 8.800 (95% CI: 2.717-28.499, p<0.05), meditation OR = 6.111 (95% CI; 2.616-14.274, p<0.05) were independent risk factors. Subjects who performed 2 h per week and 2-4 h per week physical activity, the odds ratios were 0.038 (95% CI: 0.012-0.124, p<0.05) and 0.079, (95% CI: 0.024-0.260, p<0.05), respectively. Low physical activity and use of long time relaxation are associated with cardiovascular disease in these patients. Regular participation in physical activity such as walking 2 h per week and 2-4 h per week, are associated with reduced risk of cardiovascular disease. This study suggests the importance of both leisure-time physical activity and sedentary behaviors in the prevention of CVD.

  6. Late Pleistocene and Holocene palaeoenvironments in and around the middle Caspian basin as reconstructed from a deep-sea core

    NASA Astrophysics Data System (ADS)

    Leroy, Suzanne A. G.; López-Merino, Lourdes; Tudryn, Alina; Chalié, Françoise; Gasse, Françoise

    2014-10-01

    Late Pleistocene and/or Holocene high-resolution palynological studies are available for the south basin of the Caspian Sea (CS), the world's largest lake. However, the north and middle basins have not been the object of high-resolution palynological reconstructions. This new study presents the pollen, spores and dinoflagellate cysts records obtained from a 10 m-long sediment core recovered in the middle basin, which currently has brackish waters and is surrounded by arid and semi-arid vegetation. An age-depth model built based on six radiocarbon dates on ostracod shells indicates that the sequence spans the period from 14.47 to 2.43 cal. ka BP. The present palaeoenvironmental study focuses on the top 666 cm, or from 12.44 to 2.43 cal. ka BP. At the vegetation level, the Younger Dryas is characterised by an open landscape dominated by desert vegetation composed by Amaranthaceae with shrubs and salt-tolerant plants. However, although the Early Holocene is also characterised by desert vegetation, it is enriched in various shrubs such as Ephedra and Calligonum, but tree expansion is not important at the Holocene onset. After a major shift at 8.19 cal. ka BP, the Middle Holocene displays now both the character of desert and of steppe, although some trees such as Quercus and Corylus slightly spread. The Late Holocene records steppe vegetation as dominant, with more tree diversity. Regarding the lacustrine signal, the dinocyst assemblage record fluctuates between slightly brackish conditions highlighted by Pyxidinopsis psilata and Spiniferites cruciformis, and more brackish ones - similar to the present day - with the dominance of Impagidinium caspienense. The Late Pleistocene is characterised by low salinities, related to the Khvalynian highstand. From 11.56 cal. ka BP, slightly more saline waters are reconstructed with an increase of I. caspienense for a period of 1000 years, which could be attributed to the Mangyshlak lowstand. From 10.55 cal. ka BP, low salinity

  7. Phylogenetic status of brown trout Salmo trutta populations in five rivers from the southern Caspian Sea and two inland lake basins, Iran: a morphogenetic approach.

    PubMed

    Hashemzadeh Segherloo, I; Farahmand, H; Abdoli, A; Bernatchez, L; Primmer, C R; Swatdipong, A; Karami, M; Khalili, B

    2012-10-01

    Interrelationships, origin and phylogenetic affinities of brown trout Salmo trutta populations from the southern Caspian Sea basin, Orumieh and Namak Lake basins in Iran were analysed from complete mtDNA control region sequences, 12 microsatellite loci and morphological characters. Among 129 specimens from six populations, seven haplotypes were observed. Based on mtDNA haplotype data, the Orumieh and southern Caspian populations did not differ significantly, but the Namak basin-Karaj population presented a unique haplotype closely related to the haplotypes of the other populations (0·1% Kimura two-parameter, K2P divergence). All Iranian haplotypes clustered as a distinct group within the Danube phylogenetic grouping, with an average K2P distance of 0·41% relative to other Danubian haplotypes. The Karaj haplotype in the Namak basin was related to a haplotype (Da26) formerly identified in the Tigris basin in Turkey, to a Salmo trutta oxianus haplotype from the Aral Sea basin, and to haplotype Da1a with two mutational steps, as well as to other Iranian haplotypes with one to two mutational steps, which may indicate a centre of origin in the Caspian basin. In contrast to results of the mtDNA analysis, more pronounced differentiation was observed among the populations studied in the morphological and microsatellite DNA data, except for the two populations from the Orumieh basin, which were similar, possibly due to anthropogenic causes.

  8. Geology, fossil fuel potential and environmental concerns of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Rabinowitz, P.; Yusifov, M.; Arnoldi, J.

    2003-04-01

    The fossil fuel producing areas of the Caspian region consists primarily of two basins, the Precaspian and South Caspian basins, both containing sediments in excess of 20km. The South Caspian Basin, a remnant of Tethys, was formed commencing in the Early-Middle Jurassic as a result of opening of back-arc basins behind volcanic arcs. The PreCaspian Basin extends onshore onto Kazakhstan and Russia and commenced its complicated geological evolution in the Middle Devonian. These basins are presently producing oil and gas in excess of one million barrels per day and two trillion cubic feet per day, respectively. They contain oil and gas reserves that are comparable to those of most other of the world's fossil fuel producing regions, excluding the Middle East. It is anticipated that within a decade these basins will produce over three million barrels of oil and four trillion cubic feet of gas per day. We review the economic, environmental, and geopolitical concerns with respect to exploration and recovery of the region’s fossil fuels. For one, the presence of mud volcanoes, gas hydrates, and earthquakes are a hazard for installation of oil platforms and other facilities. Pollution, attributed in large part to the fossil fuel industry, has created health and other environmental problems such as mass die-off of the Caspian seal, and in part to the large decrease in sturgeon population. Other important environmental concerns include the relatively rapid changes in sea level and desertification of the surrounding regions. There are also important legal questions with respect to ownership of resources beneath the seafloor. In addition, the transportation routes (pipelines) of fossil fuels that are anticipated to be recovered over the next decades have yet to be fully determined. Despite many of the political uncertainties, significant advances have been made in the short time since the breakup of the Soviet Union fueling optimism for the future of the region.

  9. A new fish-based multi-metric assessment index for cyprinid streams in the Iranian Caspian Sea Basin

    PubMed Central

    Mostafavi, Hossein; Schinegger, Rafaela; Melcher, Andreas; Moder, Karl; Mielach, Carina; Schmutz, Stefan

    2015-01-01

    A major issue for water resource management is the assessment of environmental degradation of lotic ecosystems. The overall aim of this study is to develop a multi-metric fish index for the cyprinid streams of the Caspian Sea Basin (MMICS) in Iran. As species diversity and composition as well as population structure in the studied streams are different to other regions, there is a substantial need to develop a new fish index. We sampled fish and environmental data of 102 sites in medium sized streams. We analysed human pressures at different spatial scales and determined applicable fish metrics showing a response to human pressures. In total, five structural and functional types of metrics (i.e. biodiversity, habitat, reproduction, trophic level and water quality sensitivity) were considered. In addition, we used 29 criteria describing major anthropogenic human pressures at sampling sites and generated a regional pressure index (RPI) that accounted for potential effects of multiple human pressures. For the MMICS development, we first defined reference sites (least disturbed) and secondly quantified differences of fish metrics between reference and impaired sites. We used a Generalised Linear Model (GLM) to describe metric responses to natural environmental differences in least disturbed conditions. By including impaired sites, the residual distributions of these models described the response range of each metric to human pressures, independently of natural environmental influence. Finally, seven fish metrics showed the best ability to discriminate between impaired and reference sites. The multi-metric fish index performed well in discriminating human pressure classes, giving a significant negative linear response to a gradient of the RPI. These methods can be used for further development of a standardised monitoring tool to assess the ecological status and trends in biological condition for streams of the whole country, considering its complex and diverse geology

  10. Use of Fatty Acid Analysis to Determine Dispersal of Caspian Terns in the Columbia River Basin, U.S.A.

    USGS Publications Warehouse

    Maranto, C.J.; Parrish, J.K.; Herman, D.P.; Punt, A.E.; Olden, J.D.; Brett, M.T.; Roby, D.D.

    2011-01-01

    Lethal control, which has been used to reduce local abundances of animals in conflict with humans or with endangered species, may not achieve management goals if animal movement is not considered. In populations with emigration and immigration, lethal control may induce compensatory immigration, if the source of attraction remains unchanged. Within the Columbia River Basin (Washington, U.S.A.), avian predators forage at dams because dams tend to reduce rates of emigration of juvenile salmonids (Oncorhynchus spp.), artificially concentrating these prey. We used differences in fatty acid profiles between Caspian Terns (Hydroprogne caspia) at coastal and inland breeding colonies and terns culled by a lethal control program at a mid-Columbia River dam to infer dispersal patterns. We modeled the rate of loss of fatty acid biomarkers, which are fatty acids that can be traced to a single prey species or groups of species, to infer whether and when terns foraging at dams had emigrated from the coast. Nonmetric multidimensional scaling showed that coastal terns had high levels of C20 and C22 monounsaturated fatty acids, whereas fatty acids of inland breeders were high in C18:3n3, C20:4n6, and C22:5n3. Models of the rate of loss of fatty acid showed that approximately 60% of the terns collected at Rock Island Dam were unlikely to have bred successfully at local (inland) sites, suggesting that terns foraging at dams come from an extensive area. Fatty acid biomarkers may provide accurate information about patterns of dispersal in animal populations and may be extremely valuable in cases where populations differ demonstrably in prey base. ??2011 Society for Conservation Biology.

  11. A study on distribution of chlorophyll-a in the coastal waters of Anzali Port, south Caspian Sea

    NASA Astrophysics Data System (ADS)

    Jamshidi, S.; Abu Bakar, N. Bin

    2011-02-01

    Phytoplankton as chlorophyll-containing organisms is the first step of production in most marine processes and food chains. Nutrient enhancement in the seawater due to the discharge of agricultural, industrial, and urban wastes threatens the Caspian Sea environment. Increasing concentrations of chlorophyll-a in seawater, in reaction to the elevation of nutrient supply can have severely damaging effects on the marine environment of the Caspian. In this research, seasonal variability of the chlorophyll-a concentrations in the western part of the southern coastal waters of the Caspian Sea near Iranian coast was examined using field observations. The data showed that the most chlorophyll-a was found below the sea surface. The thermal stratification in water column and outflow of the Anzali Lagoon affect the chlorophyll-a concentrations in the region. Concentrations of chlorophyll-a were recorded in midsummer in a range of 0.2-3.4 mg m-3.

  12. Plate Tectonics: Geodynamic models of evolution of oil and gas bearing basins of Kazakhstan

    SciTech Connect

    Zholtayev, G. )

    1994-07-01

    Five types of sedimentary basins in Kazakhstan have been recognized by using plate tectonics to reinterpret geological and geophysical data: (1) intracontinental, central pre-Caspian, above rift, south pre-Caspian; (2) passive margin, east pre-Caspian; (3) back-arc, Turgan and Sir-Daria; (4) intra-arc, north Kisil-Koum, interior, Tengis and Chu-Sarisiu; and (5) marginal, north Usturt. Paleozoic history of these basins was connected with the spreading and collision of two lithospheric plates: east European and Kazakhstanian, which were separated by the paleo-Ural Ocean. Different tectonic positions of sedimentary basins were the reason for their different oil and gas potential.

  13. Molecular resolution of the family Dreissenidae (Mollusca: Bivalvia) with emphasis on Ponto-Caspian species, including first report of Mytilopsis leucophaeata in the Black Sea basin.

    PubMed

    Therriault, Thomas W; Docker, Margaret F; Orlova, Marina I; Heath, Daniel D; MacIsaac, Hugh J

    2004-03-01

    Considerable uncertainty exists in determination of the phylogeny among extant members of the Dreissenidae, especially those inhabiting the Ponto-Caspian basin, as multiple systematic revisions based on morphological characteristics have failed to resolve relationships within this group of bivalves. In this study we use DNA sequence analyses of two mitochondrial gene fragments, 16S rRNA and cytochrome c oxidase subunit I (COI), to determine phylogenetic relationships among Dreissena rostriformis, D. bugensis, D. polymorpha, D. stankovici, Congeria kusceri, and Mytilopsis leucophaeata. Dreissena stankovici was determined to represent a sister taxa to D. polymorpha and both are more closely related to other extant Dreissena species than Congeria or Mytilopsis. Sequence divergence between D. rostriformis and D. bugensis was relatively low (0.3-0.4%), suggesting that these two taxa constitute a single species. However, environmental differences suggest two races of D. rostriformis, a brackish water race (rostriformis) and a freshwater race (bugensis). Spread of bugensis-type individuals into habitats in the Caspian Sea that are occupied by rostriformis-type individuals may create novel hybridization opportunities. Species-specific molecular markers also were developed in this study since significant intraspecific variation in morphological features complicates dreissenid identification. Using two gene fragments (nuclear 28S and 16S), we identified restriction fragment length polymorphisms (RFLPs) that distinguish among D. rostriformis/bugensis, D. polymorpha, and D. stankovici and revealed the presence of a cryptic invader to the Black Sea basin, Mytilopsis leucophaeata. This is the first report of this North American native in southern Europe.

  14. Municipal solid waste management on the south coastline of the Caspian Sea (Golestan, Mazandaran, and Guilan Provinces of Iran).

    PubMed

    Abduli, Mohammad Ali; Bidhendi, Gholamreza Nabi; Nasrabadi, Touraj; Hoveidi, Hassan

    2007-12-01

    The Caspian region (including the Golestan, Mazandaran, and Guilan provinces of Iran) occupies 58,678 square kilometers (22,651 square miles) and has a population of 6,270,192, according to the census of 1996. This part of Iran is attractive to tourists because of its proximity to the Caspian Sea. In addition, the region boasts invaluable forests and grasslands, and is the exclusive producer in the country of key agricultural crops like rice and tea. The lack of systematic solid waste management has put this region on the edge of irreparable environmental damage. The large number and dispersion of open-dumping landfills, as well as the faded role of functional elements like waste minimization and processing, have sped up the environmental deterioration. This article evaluates the current status of solid waste management in the Caspian region and suggests practical alternatives. As a result of a field and desk study, the authors offer some instructions for separation of putrescibles, paper and cardboard, plastics, and so forth. Finally, after considering all aspects of the environmental impact assessments for different alternatives, the authors recommend the construction of two compost-producing facilities in Golestan province with a combined capacity of 500 metric tons per day and a total cost of $60,000, and four incineration sites in southern and southwestern parts of the region (Mazandaran and Guilan provinces) with a total capacity of 2,000 metric tons per day and total cost of $75 million.

  15. Dietary habits of invasive Ponto-Caspian gobies in the Croatian part of the Danube River basin and their potential impact on benthic fish communities.

    PubMed

    Piria, Marina; Jakšić, Goran; Jakovlić, Ivan; Treer, Tomislav

    2016-01-01

    Invasive Ponto-Caspian (P-C(1)) gobies have recently caused dramatic changes in fish assemblage structures throughout the Danube basin. While their presence in the Croatian part of the basin has been noted and distribution studied, their dietary habits and impacts on native fish communities have, until now, been unknown. In 2011, 17 locations in the Sava River Basin were sampled for fish and 15 for benthic invertebrates. Fish population monitoring data, available for nine seasons (2003-2006 and 2010-2014) and 12 locations, were used to analyse the impacts of P-C gobies on benthic fish abundance. Gut content analysis indicates that the monkey goby Neogobius fluviatilis diet is very diverse, but dominated by Trichoptera, Chironomidae, Bivalvia and Odonata. The diet overlaps considerably with the round goby Neogobius melanostomus diet, although Gastropoda are dominant in the latter's diet. Small fish and Gammarus sp. dominate the bighead goby Ponticola kessleri diet. Comparison of gut content with the prey available in the environment indicates that monkey and round gobies exhibit preference for Trichoptera, Megaloptera and Coleoptera, and bighead goby for Trichoptera, Gammarus sp. and Pisces. P-C gobies in the Sava River are spreading upstream, towards the reaches with lower fish diversity. Analyses indicate potentially positive impacts of P-C gobies' presence on some fish populations: round and bighead goby on Balkan golden loach Sabanejewia balcanica and monkey goby on common carp Cyprinus carpio, crucian carp Carassius carassius, burbot Lota lota and Balkan loach Cobitis elongata. However, there are also indications that bighead and round goby could adversely impact the native chub Squalius cephalus and zingel Zingel zingel populations, respectively. As P-C gobies are still in the expansionary period of invasion and the ecosystem still adapting to new circumstances, continued monitoring of fish population dynamics in the Sava basin is needed to determine the

  16. Dietary habits of invasive Ponto-Caspian gobies in the Croatian part of the Danube River basin and their potential impact on benthic fish communities.

    PubMed

    Piria, Marina; Jakšić, Goran; Jakovlić, Ivan; Treer, Tomislav

    2016-01-01

    Invasive Ponto-Caspian (P-C(1)) gobies have recently caused dramatic changes in fish assemblage structures throughout the Danube basin. While their presence in the Croatian part of the basin has been noted and distribution studied, their dietary habits and impacts on native fish communities have, until now, been unknown. In 2011, 17 locations in the Sava River Basin were sampled for fish and 15 for benthic invertebrates. Fish population monitoring data, available for nine seasons (2003-2006 and 2010-2014) and 12 locations, were used to analyse the impacts of P-C gobies on benthic fish abundance. Gut content analysis indicates that the monkey goby Neogobius fluviatilis diet is very diverse, but dominated by Trichoptera, Chironomidae, Bivalvia and Odonata. The diet overlaps considerably with the round goby Neogobius melanostomus diet, although Gastropoda are dominant in the latter's diet. Small fish and Gammarus sp. dominate the bighead goby Ponticola kessleri diet. Comparison of gut content with the prey available in the environment indicates that monkey and round gobies exhibit preference for Trichoptera, Megaloptera and Coleoptera, and bighead goby for Trichoptera, Gammarus sp. and Pisces. P-C gobies in the Sava River are spreading upstream, towards the reaches with lower fish diversity. Analyses indicate potentially positive impacts of P-C gobies' presence on some fish populations: round and bighead goby on Balkan golden loach Sabanejewia balcanica and monkey goby on common carp Cyprinus carpio, crucian carp Carassius carassius, burbot Lota lota and Balkan loach Cobitis elongata. However, there are also indications that bighead and round goby could adversely impact the native chub Squalius cephalus and zingel Zingel zingel populations, respectively. As P-C gobies are still in the expansionary period of invasion and the ecosystem still adapting to new circumstances, continued monitoring of fish population dynamics in the Sava basin is needed to determine the

  17. South Fork Holston River basin 1988 biomonitoring

    SciTech Connect

    Saylor, C.F.; Ahlstedt, S.A.

    1990-06-01

    There is concern over the effects of shifts in land use use practices on the aquatic fauna of streams in the South Fork Holston River basin in northwestern North Carolina and southwestern Virginia. Trout reproduction has noticeably declined in the Watauga River subbasin. The Watauga River and Elk River subbasins have been subjected to commercial and resort development. The Middle fork Holston River and the upper South Fork Holston River subbasins have been affected by agricultural and mining activities, respectively (Cox, 1986). To aid reclamation and management of the South Fork Holston basin, Tennessee Valley Authority (TVA) biologists conducted biomonitoring--including index of biotic integrity and macroinvertebrate sampling--on the Middle Fork Holston, South Fork Holston, Watauga, and Elk Rivers to assess cumulative impairment related to changes in habitat and pollutant loading in these subbasins. Biomonitoring can detect environmental degradation, help document problem areas, and assist in development of strategies for managing water quality. This report discusses the methods and materials and results of the biomonitoring of South Fork Holston River Basin. 13 refs., 5 figs., 12 tabs.

  18. Comparison of methods to improve induction of spermiation in wild-caught carp (Cyprinus carpio carpio), a threatened species from the Caspian Sea basin.

    PubMed

    Vazirzadeh, Arya; Farhadi, Ahmad; Naseri, Mahmood; Jeffs, Andrew

    2016-07-01

    Wild carp (Cyprinus carpio carpio) forms the basis of an important fishery in the Southern Caspian Sea Basin which is increasingly underpinned by the release of cultured juveniles. A significant bottleneck to hatchery-rearing of juveniles is the spermiation of male broodstock. Therefore, four approaches to improving spermiation were investigated. The effectiveness of two delivery methods for the sustained release of salmon gonadotropin releasing hormone analogue (sGnRHa; i.e., via intramuscular cholesterol pellet vs emulsion injection) on the spermiation success and duration, sperm quality and quantity over 14days in wild-caught carp were compared to single injection of sGnRHa with Pimozide(®) (Linpe method) or carp pituitary extract (CPE). The consequence of the spermiation treatments on resulting embryonic quality was evaluated for subsequent fertilization and hatching success from wild male carp (mean weight±S.D. 1021±112g). All hormonal treatments, except for Linpe method, led to 100% spermiation of treated fish compared to only 25% in the control with no hormone intervention. The duration of spermiation, as well as the various quantitative variables of the sperm and the mean total sperm production were all generally improved with the sustained hormone delivery compared with the acute treatments. The GnRHa-FIA was the most effective method for improving spermiation. PMID:27133180

  19. Depositional cycles and Fe/Mn ratio in Upper Absheron substage succession in the western flank of the South Khazarian/Caspian depression of the Azerbaijan Republic

    NASA Astrophysics Data System (ADS)

    Amirov, Elnur

    2016-04-01

    The Caspian Sea, the largest land locked basin in the world, isolated from ParaTethys at the end of Messinian. Since that time sedimentation there took place under conditions of isolated basin temporarily connected with Black Sea in Upper Pliocene (Akchagyl). For the first time very detailed study (centimeter scale) of outcrop was carried out for stratigraphy and paleoecology of the Upper absheron substage deposits cropped out in the Western flank of the South Caspian depression (Shikhovo exposure) of the Azerbaijan Republic. The data obtained demonstrated the high-frequency cyclicity in sedimentation accompanied by rapid lateral and vertical depositional environment change. Most of these system tracts have not yet been studied in detail. The depositional setting during accumulation of this succession has changed within shore face-shelf environment. On the background of these cycles, the depositional series of a higher order containing sediments deposited during very small-scale sea level fall and rise occur. Some information contained in this document is the new data, due to more recent observations and interpretations. The results of the field works on exposures of the Eopleistocene deposits exposed in the Western flank of the South Caspian depression (Shikhovo outcrop) demonstrated the high-frequency cyclicity in sedimentation. It is possible to observe several full depositional sequences developed from transgressive system tract to low stand system tract, to high stand system tract and return to sedimentation under conditions of sea level rise. The studied successions are characterized by steep foresets, about 12°, which is evidence of steep slope existed during the sediment accumulation. On the background of above mentioned cycles, the depositional series of a higher order containing sediments formed during very small-scale sea level fall and rise occur. Below we give the lithofacial characteristics of one full depositional cycle and our interpretation of

  20. Palaeogeography of the Caspian Sea marine Pleistocene

    NASA Astrophysics Data System (ADS)

    Yanina, Tamara; Svitoch, Aleksander; Makshaev, Radik; Khomchenko, Denis

    2016-04-01

    Vertical succession of the fossil molluscs of Didacna genus along the Pleistocene sequence of the Caspian Sea area allows for detailed subdivision of the sediments. Zone, i.e. the Caspian Sea Pleistocene, is the highest stratigraphical unit of the regional Quaternary stratigraphic scale. It corresponds to the biozone of Didacna Eichwald subgenus. Based on the fossil groups of Didacna molluscs, the deposits are subdivided into the Baku, Urundzhik-Singil', lower and upper Khazarian, Khvalinian, and post-Khvalinian horizons. Further subdision is based on the changes in Didacna assemblages. Three big transgressive epochs are distinguished in the Pleistocene history of the Caspian Sea that were separated by deep and long regressions. These are the Baku, early Khazarian and Khvalinian transgressions. In transgressive sea basins, the sea level reached the height of 40-50 m and was regulated by the outflow of the Caspian waters into the Black Sea via the Manych depression. The areas of transgressive basins were similar. At the Caucasian coast, the extent of the Baku and early Khazarian transgressions exceeded that of the Khvalinian transgression, while in the Northern Caspian Sea Region the latter was slightly more extensive than the preceding ones. The Urundzhik, late Khazarian and New Caspian transgressions represented sea-level rise of lower rank. All of them were recorded within big regressive epochs being usually related to warm (interglacial) climatic conditions: Singil' (Likhvin), Mikulino and Holocene, respectively. Like at present, the Pleistocene Caspian Sea represented a self-regulating system. Maximal extent of ancient sea basins was dependent upon the height of the Manych sill (that was the main regulating factor), the amount of precipitation, river runoff, and decrease in evaporation. Minimal extent of the sea basin was dependent upon the area and capacity of its southern and middle depressions. At the same time, the rest states (extents) of the Caspian Sea

  1. Fossil facies of the Greater Caspian region

    NASA Astrophysics Data System (ADS)

    Svitoch, A. A.

    2015-05-01

    The Pliocene-Pleistocene marine sediments of the Great Caspian region host various lithological fossil facies, which reflect specific sedimentation conditions caused by different structural-geomorphologic settings, tectonic regimes, climates, and hydrologies. The facies of shelf, epicontinental basins, ingression gulfs and estuaries, intermontane and mountainous basins, and deep-sea depressions form a hierarchy of geological bodies from types to subtypes. Paragenetic associations of fossil facies, which form various series in space and along the section, are typical of marine sediments.

  2. Volga River Delta and Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This true-color MODIS image from May 10, 2002, captures Russia's Volga River (running south through the center) emptying into the northern portion of the Caspian Sea. The waters of the Caspian Sea are quite murky in this image, highlighting the water quality problems plaguing the sea. The sea is inundated with sewage and industrial and agricultural waste, which is having measurable impact on human health and wildlife. According reports from the Department of Energy, in less than a decade the sturgeon catch dropped from 30,000 tons to just over 2,000 tons. National and international groups are currently joining together to find strategies of dealing with the environmental problems of the Caspian Sea. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  3. Basin analysis of South Mozambique graben

    SciTech Connect

    Iliffe, J.; Lerche, I.; De Buyl, M.

    1987-05-01

    Basin analysis of the South Mozambique graben between latitudes 25/sup 0/ and 26/sup 0/ and longitudes 34/sup 0/ and 35/sup 0/ demonstrates how modeling techniques may help to assess the oil potential of a speculative basin with only minimal seismic data. Two-dimensional restoration of the seismic profiles, using a backstripping and decompaction program on pseudowells linked with structural reconstruction, assesses the rift's two-phase extensional history. Since no well or thermal indicator data exist within the basin, the thermal history had to be derived from extensional models. The best fit of observed subsidence curves and those predicted by the models results in values of lithospheric extension (gamma). The disagreement in observed and theoretical basement subsidence curves was minimized by taking a range of gamma for each model for each well. These extension factors were then used in each model's equations for paleoheat flux to derive the heat-flow histories. (It is noted that a systematic basinwide variance of gamma occurs.) The heat-flux histories were then used with a one-dimensional fluid flow/compaction model to calculate TTI values and oil windows. A Tissot generation model was applied to each formation in every well for kerogen Types I, II, and III. The results were contoured across the basin to assess possible oil- and gas-prone formations. The extensional, burial, and thermal histories are integrated into an overall basin development picture and provide an oil and gas provenance model. Thus they estimate the basinwide hydrocarbon potential and also gain insight into the additional data necessary to significantly decrease the uncertainty.

  4. Geology, prospects in Orange basin offshore western South Africa

    SciTech Connect

    Muntingh, A. Ltd., Parow )

    1993-01-25

    With the fast changing political situation in South Africa it has become possible for Soekor (Pty.) Ltd. To invite international companies to participate in oil and gas exploration in the South African part of the Orange basin. This paper reports on the Orange basin, which comprises a 130,000 sq km area off western South Africa that extends northwards into Namibia, represents a large frontier basin with known hydrocarbon accumulations and the potential for giant fields. Comprehensive seismic coverage and a recent deep-water seismic survey in the Orange basin indicate exciting opportunities in the form of shallow and deep-water plays.

  5. South Platte River Basin - Colorado, Nebraska, and Wyoming

    USGS Publications Warehouse

    Dennehy, Keuin F.; Litke, David W.; Tate, Cathy M.; Heiny, Janet S.

    1993-01-01

    The South Platte River Basin was one of 20 study units selected in 1991 for investigation under the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program. One of the initial tasks undertaken by the study unit team was to review the environmental setting of the basin and assemble ancillary data on natural and anthropogenic factors in the basin. The physical, chemical, and biological quality of the water in the South Platte River Basin is explicitly tied to its environmental setting. The resulting water quality is the product of the natural conditions and human factors that make up the environmental setting of the basin.

  6. Ovarian development and related changes in steroid hormones in female wild common carp (Cyprinus carpio carpio), from the south-eastern Caspian Sea.

    PubMed

    Vazirzadeh, A; Mojazi Amiri, B; Fostier, A

    2014-12-01

    Wild common carp (Cyprinus carpio carpio) is a native valuable but threatened species from the south-eastern Caspian Sea in which the endocrine control of its reproduction has not been studied. The objectives of this research were to study the reproductive strategy and changes in steroid hormones during ovarian development. From October 2009 to June 2010, 65 adult females were caught from the Golestan coast (Iran) and the ovarian histology, and gonadosomatic and hepatosomatic indices (GSI and HSI) were studied. Also, the plasma profiles of steroid hormones including testosterone (T), 17β-estradiol (E2) and 17α-, 20β-dihydroxyprogesterone (DHP) were measured by radioimmunoassay. The GSI increased gradually during sampling times and reached maximum value at the peak of reproduction season, but the HSI decreased during spawning season. All stages of ovarian development, except the stage of Balbiani bodies, were recorded macro- and microscopically. Spent fish were caught at six of nine sampling times. The peaks of spawning were at late winter and early spring. The results of this study showed that the majority of wild carp collected during the sampling period displayed asynchronous oocyte development. Plasma T showed no significant differences during sampling times or at different stages of ovarian development. The level of E2 decreased gradually during sampling times reached minimum value at the spawning season, and highest value was recorded at tertiary vitellogenesis stage. The plasma levels of DHP during late winter and early spring were significantly higher than those of other sampling periods and its maximum level associated with oocyte maturation stage.

  7. HIGH-RESOLUTION SEISMIC VELOCITY AND ATTENUATION MODELS OF THE CAUCASUS-CASPIAN REGION

    SciTech Connect

    Mellors, R; Gok, R; Pasyanos, M; Skobeltsyn, G; Teoman, U; Godoladze, T; Sandvol, E

    2008-07-01

    The southwest edge of Eurasia is a tectonically and structurally complex region that includes the Caspian and Black Sea basins, the Caucasus Mountains, and the high plateaus south of the Caucasus. Using data from 25 broadband stations located in the region, new estimates of crustal and upper mantle thickness, velocity structure, and attenuation are being developed. Receiver functions have been determined for all stations. Depth to Moho is estimated using slant stacking of the receiver functions, forward modeling, and inversion. Moho depths along the Caspian and in the Kura Depression are in general poorly constrained using only receiver functions due to thick sedimentary basin sediments. The best fitting models suggest a low velocity upper crust with Moho depths ranging from 30 to 40 km. Crustal thicknesses increase in the Greater Caucasus with Moho depths of 40 to 50 km. Pronounced variations with azimuth of source are observed indicating 3D structural complexity and upper crustal velocities are higher than in the Kura Depression to the south. In the Lesser Caucasus, south and west of the Kura Depression, the crust is thicker (40 to 50 km) and upper crustal velocities are higher. Work is underway to refine these models with the event based surface wave dispersion and ambient noise correlation measurements from continuous data. Regional phase (Lg and Pg) attenuation models as well as blockage maps for Pn and Sn are being developed. Two methods are used to estimate Q: the two-station method to estimate inter-station Q and the reversed, two-station, two event method. The results are then inverted to create Lg and Pg Q maps. Initial results suggest substantial variations in both Pg and Lg Q in the region. A zone of higher Pg Q extends west from the Caspian between the Lesser and Greater Caucasus and a narrow area of higher Lg Q is observed.

  8. View of former preliminary sedimentation basin, looking east from south ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of former preliminary sedimentation basin, looking east from south side of low-lift pumping station. - Robert B. Morse Water Filtration Plant, 10700 and 10701 Columbia Pike, Silver Spring, Montgomery County, MD

  9. Archean foreland basin tectonics from the Witwatersrand, South Africa

    SciTech Connect

    Burke, K.; Kidd, W.S.F.; Kusky, T.M.

    1985-01-01

    The Witwatersrand Basin of South Africa is the best-known of Archean sedimentary basins and contains some of the largest gold reserves in the world. Sediments in the basin include a lower flysch-type sequence and an upper molassic facies, both of which contain abundant silicic volcanic detritus. The strata are thicker and more proximal on the northwestern side of the basin which is, at least locally, bound by thrust faults. These and other features indicate that the Witwatersrand strata were deposited in a foreland basin. A regional geologic synthesis suggests that his basin developed initially on the cratonward side of an Andean-type arc. Remarkably similar Phanerozoic basins may be found in the southern Andes above zones of shallow subduction. We suggest that the continental collision between the Kaapvaal and Zimbabwe Cratons at about 2.7 Ga caused further subsidence and deposition in the Witwatersrand Basin. Regional uplift during this later phase of development placed the basin on the cratonward edge of a collision-related plateau, now represented by the Limpopo Province. Striking similarities are seen between this phase of Witwatersrand Basin evolution and active basins located north of the Tibetan Plateau. The geologic evidence is not so compatible with earlier suggestions that the Witwatersrand strata were deposited in a rift or half-graben.

  10. Archean foreland basin tectonics in the Witwatersrand, South Africa

    SciTech Connect

    Burke, K.; Kidd, W.S.F.; Kusky, T.M.

    1986-06-01

    The Witwatersrand Basin of South Africa is the best-known of Archean sedimentary basins and contains some of the largest gold reserves in the world. Sediments in the basin include a lower flysch-type sequence and an upper molassic facies, both of which contain abundant silicic volcanic detritus. The strata are thicker and more proximal on the northwestern side of the basin which is, at least locally, bound by thrust faults. These features indicate that the Witwatersrand strata may have been deposited in a foreland basin and a regional geologic synthesis suggests that this basin developed initially on the cratonward side of an Andean-type arc. Remarkably similar Phanerozoic basins may be found in the southern Andes above zones of shallow subduction. It is suggested that the continental collision between the Kaapvaal and Zimbabwe Cratons at about 2.7 Ga caused further subsidence and deposition in the Witwatersrand Basin. Regional uplift during this later phase of development placed the basin on the cratonward edge of a collision-related plateau, now represented by the Limpopo Province. Similarities are seen between this Phase of Witywatersrand Basin evolution and that of active basins north of the Tibetan Plateau. The geologic evidence does not agree with earlier suggestions that the Witwatersrand strata were deposited in a rift or half-graben. 64 references.

  11. Archean foreland basin tectonics in the Witwatersrand, South Africa

    NASA Technical Reports Server (NTRS)

    Burke, K.; Kidd, W. S. F.; Kusky, T. M.

    1986-01-01

    The Witwatersrand Basin of South Africa is the best-known of Archean sedimentary basins and contains some of the largest gold reserves in the world. Sediments in the basin include a lower flysch-type sequence and an upper molassic facies, both of which contain abundant silicic volcanic detritus. The strata are thicker and more proximal on the northwestern side of the basin which is, at least locally, bound by thrust faults. These features indicate that the Witwatersrand strata may have been deposited in a foreland basin and a regional geologic synthesis suggests that this basin developed initially on the cratonward side of an Andean-type arc. Remarkably similar Phanerozoic basins may be found in the southern Andes above zones of shallow subduction. It is suggested that the continental collision between the Kaapvaal and Zimbabwe Cratons at about 2.7 Ga caused further subsidence and deposition in the Witwatersrand Basin. Regional uplift during this later phase of development placed the basin on the cratonward edge of a collision-related plateau, now represented by the Limpopo Province. Similarities are seen between this Phase of Witywatersrand Basin evolution and that of active basins north of the Tibetan Plateau. The geologic evidence does not agree with earlier suggestions that the Witwatersrand strata were deposited in a rift or half-graben.

  12. Archean foreland basin tectonics in the Witwatersrand, South Africa

    NASA Technical Reports Server (NTRS)

    Burke, K.; Kidd, W. S. F.; Kusky, T. M.

    1986-01-01

    The Witwatersrand Basin of South Africa is the best-known of Archean sedimentary basins and contains some of the largest gold reserves in the world. Sediments in the basin include a lower flysch-type sequence and an upper molassic facies, both of which contain abundant silicic volcanic detritus. The strata are thicker and more proximal on the northwestern side of the basin which is, at least locally, bound by thrust faults. These features indicate that the Witwatersrand strata may have been deposited in a foreland basin and a regional geologic synthesis suggests that this basin developed initially on the cratonward side of an Andean-type arc. Remarkably similar Phanerozoic basins may be found in the southern Andes above zones of shallow subduction. It is suggested that the continental collision between the Kaapvaal and Zimbabwe Cratons at about 2.7 Ga caused further subsidence and deposition in the Witwatersrand Basin. Regional uplift during this later phase of development placed the basin on the cratonward edge of a collision-related plateau, now represented by the Limpopo Province. Similarities are seen between this phase of Witwatersrand Basin evolution and that of active basins north of the Tibetan Plateau. The geologic evidence does not agree with earlier suggestions that the Witwatersrand strata were deposited in a rift or half-graben.

  13. Full depositional cycles and Ca/Mg ratio in marine upper Baku regiostage succession in the Western flank of the South Caspian depression

    NASA Astrophysics Data System (ADS)

    Amirov, Elnur

    2010-05-01

    The results of the field works on exposures of the Lower Pleistocene deposits located in the Western flank of the South Caspian depression (Shikhov outcrop) demonstrated the high-frequency cyclicity in sedimentation accompanied by rapid lateral and vertical depositional environmental change. It is possible to observe several full depositional sequences developed from low stand system tract to transgressive system tract and high stand system tract. Return to sedimentation under conditions of sea level low stand marks beginning of the next depositional cycle. The depositional setting during accumulation of this succession has changed within shore face-shelf environment. On the background of these cycles, the depositional series of higher order containing sediments formed during very small-scale sea level fall and rise occur. Below I give the lithofacial characteristics of one full depositional cycle and our interpretation of depositional environment during its sedimentation. Bedset I is subdivided into 10 interbeds with total thickness 2m70cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone, organogenic limestone and shelly sandstone. We consider these series as high stand system tract. Bedset II is the massive and homogeneous, thickness 1m10cm. Lithologically represented by organogenic limestones. We consider these series as low stand system tract. Bedset III is subdivided into 7 interbeds with total thickness 1m5cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone, organogenic limestone and shelly sandstone. We consider these series as high stand system tract. Bedset IV is the massive and homogeneous, thickness 2m. Lithologically represented by organogenic limestones. We consider these series as low stand system tract. Bedset V is subdivided into 13 interbeds with total thickness 4m30cm. Lithologically represented by alternation of sand, sandstone, sandy organogenic limestone and

  14. Groundwater quality in the South Coast Interior Basins, California

    USGS Publications Warehouse

    Parsons, Mary C.; Belitz, Kenneth

    2014-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s untreated groundwater quality and increases public access to groundwater-quality information. The South Coast Interior Basins constitute one of the study units being evaluated.

  15. The monitoring system of the Kazakhstan sector of Caspian Sea

    NASA Astrophysics Data System (ADS)

    Shabanova, Luydmila; Khachaturov, Vladimir; Zlotov, Aleksandr

    2010-05-01

    The monitoring system of the Kazakhstan sector of Caspian Sea The Caspian Sea is the largest closed reservoir in the world, which washes the western part of Kazakhstan. The area of water territory is 371,000 sq km; the sea level is lower than the level of the ocean on 28.5 m (1971). Maximum depth is 1,025m (in the southern part); the Kazakhstan part is not deep, and the depth of the North Caspian sea is about 15-20 m. The Caspian Sea is divided according to physical and geographical conditions to 3 parts - North Caspian, Middle Caspian and South Caspian Sea. Fauna is represented by 1809 species, 415 of which belong to the vertebrates, 101 species of fish, it also has the majority of the world's sturgeon, freshwater fish - roach, carp, pike, saltwater fish - carp, mullet, sprats, Kutum, bream, salmon, perch, pike, mammal - caspian seal. The plant world is represented by 728 species, of which algae are dominated - blue-green, diatoms, red, brown, Stoneworts and others, from flowering - eelgrass and seagrass. Development of sea oil-and-gas deposits of the Kazakhstan sector of Caspian sea entails increase of anthropogenous pressure on the environment. According to preliminary estimates, the volume of recoverable hydrocarbon resources in the Kazakhstan sector of Caspian Sea is about 8.0 billion tons per year. The impact of terrestrial and marine infrastructure, oil and gas facilities on natural systems is reflected in discharges and emissions into the environment of gaseous, solid and liquid pollutants, consumption of natural resources for industrial, farm and household needs, and violation of coastal landscapes. Dangerous influence on the environment is burning natural oil gas on torches. In this regard, there is a need for a system of state monitoring. In a basis of environmental monitoring system of the Kazakhstan sector of Caspian Sea has been put an ecosystem approach, creation of an automated system on the basis of GIS technologies and modeling of forecasts of

  16. The geologically recent giant impact basins at Vesta's south pole.

    PubMed

    Schenk, Paul; O'Brien, David P; Marchi, Simone; Gaskell, Robert; Preusker, Frank; Roatsch, Thomas; Jaumann, Ralf; Buczkowski, Debra; McCord, Thomas; McSween, Harry Y; Williams, David; Yingst, Aileen; Raymond, Carol; Russell, Chris

    2012-05-11

    Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satellites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite-eucrite-diogenite meteorites.

  17. The geologically recent giant impact basins at Vesta's south pole.

    PubMed

    Schenk, Paul; O'Brien, David P; Marchi, Simone; Gaskell, Robert; Preusker, Frank; Roatsch, Thomas; Jaumann, Ralf; Buczkowski, Debra; McCord, Thomas; McSween, Harry Y; Williams, David; Yingst, Aileen; Raymond, Carol; Russell, Chris

    2012-05-11

    Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satellites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite-eucrite-diogenite meteorites. PMID:22582256

  18. VIEW OF SOUTH STORAGE BASIN NUMBER 1 OF FUEL STORAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SOUTH STORAGE BASIN NUMBER 1 OF FUEL STORAGE BUILDING (CPP-603). PHOTO TAKEN LOOKING NORTHEAST. INL PHOTO NUMBER HD-54-18-4. Mike Crane, Photographer, 8/2005 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

  19. RAINFALL-RUNOFF MECHANICS FOR DEVELOPED URBAN BASINS, SOUTH FLORIDA.

    USGS Publications Warehouse

    Miller, Robert A.

    1984-01-01

    Rainfall-runoff data, collected by the US Geological Survey as part of an urban hydrology study in south Florida, were analyzed to find relations between depths of rainfall and basin runoff. Data were collected for about 300 runoff events on four different urban land-use basins - commercial, highway, single-family residential, and apartment. These data were collected from sewers that carried only stormwater runoff. In analyzing the rainfall-runoff data, three types of relations were found. A one-curve, linear relation occurred for the commercial basin that has 98 percent of the basin as hydraulically effective impervious area. A two-curve, intercepted relation occurred for the highway basin - a linear curve for the low and medium events observed and a second-degree curve for high events observed. A two-curve, disjointed relation occurred for the remaining two basins - the residential basin and the apartment basin. This relation also contained a linear curve for low and medium events and a second-degree curve for the high events. However, the two curves do not intersect, but are disjointed.

  20. Sample return from the lunar South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Duke, M. B.

    2003-06-01

    Automated sample return missions to the South Pole — Aitken Basin on the lunar far side are proposed as the best means of addressing major problems concerning the early impact history of the inner solar system, the nature of very large impact events, and the early differentiation of rocky planets. The opportunity to propose such missions has been opened by the recommendations of the U. S. National Research Council's Decadal Study of Solar System Exploration and the creation by NASA of the New Frontiers Program, which will support missions of intermediate cost, between the Discovery Program and large missions. A proposal for a South Pole — Aitken Basin Sample Return Mission was submitted to the Discovery Program in 2000, but not fimded. The New Frontiers Program, with a somewhat less stringent budget constraint, should allow several of the potential risks associated with the Discovery proposal to be addressed, including scientific and programmatic risks. A principal goal of current mission studies is to determine whether, within the New Frontiers Program's cost constraints, two separate samples could be collected from areas of different post-Basin geological history. If accepted by the New Frontiers Program, a South Pole — Aitken Basin sample return mission could be flown as early as 2008-2009.

  1. South Atlantic sag basins: new petroleum system components

    SciTech Connect

    Henry, S.G. Mohriak, W.U.; Mello, M.R.

    1996-08-01

    Newly discovered pre-salt source rocks, reservoirs and seals need to be included as components to the petroleum systems of both sides of the South Atlantic. These new components lie between the pre-salt rift strata and the Aptian salt layers, forming large, post-rift, thermal subsidence sag basins. These are differentiated from the older rift basins by the lack of syn-rift faulting and a reflector geometry that is parallel to the base salt regional unconformity rather than to the Precambrian basement. These basins are observed in deep water regions overlying areas where both the mantle and the crust have been involved in the extension. This mantle involvement creates post-rift subsiding depocenters in which deposition is continuous while proximal rift-phase troughs with little or no mantle involvement are bypassed and failed to accumulate potential source rocks during anoxic times. These features have been recognized in both West African Kwanza Basin and in the East Brasil Rift systems. The pre-salt source rocks that are in the West African sag basins were deposited in lacustrine brackish to saline water environment and are geochemically distinct from the older, syn-rift fresh to brackish water lakes, as well as from younger, post-salt marine anoxic environments of the drift phase. Geochemical analyses of the source rocks and their oils have shown a developing source rock system evolving from isolated deep rift lakes to shallow saline lakes, and culminating with the infill of the sag basin by large saline lakes to a marginally marine restricted gulf. Sag basin source rocks may be important in the South Atlantic petroleum system by charging deep-water prospects where syn-rift source rocks are overmature and the post-salt sequences are immature.

  2. Implication of drainage basin parameters of a tropical river basin of South India

    NASA Astrophysics Data System (ADS)

    Babu, K. J.; Sreekumar, S.; Aslam, Arish

    2016-03-01

    Drainage morphometry provides quantitative description of the drainage system which is an important aspect of the characterisation of watersheds. Chalakudi River is one of the important rivers of the South India which has attracted attention of many environmental scientists recently because of the proposed Athirapally Hydel Project across the river. SRTM (Shuttle Radar Topographic Mission) data were used for preparing DEM (Digital Elevation Model), Aspect Map and Slope Map. Geographical Information System (GIS) was used for the evaluation of linear, areal and relief aspects of morphometric parameters. The study reveals that the terrain exhibits dentritic and trellis pattern of drainage. The Chalakudi River Basin has a total area of 1,448.73 km2 and is designated as seventh-order basin. The drainage density of the basin is estimated as 2.54 and the lower-order streams mostly dominate the basin. The high basin relief indicates high runoff and sediment transport. The elongation ratio of the Chalakudi Basin is estimated as 0.48 and indicates that the shape of the basin is elongated. The development of stream segments in the basin area is more or less effected by rainfall. Relief ratio indicates that the discharge capability of watershed is very high and the groundwater potential is meagre. The low value of drainage density in spite of mountainous relief indicates that the area is covered by dense vegetation and resistant rocks permeated by fractures and joints. These studies are helpful in watershed development planning and wise utilization of natural resources.

  3. Sampling South Pole-Aitken Basin: The Moonrise Approach

    NASA Technical Reports Server (NTRS)

    Jolliff, B. L.; Shearer, C. K.; Cohen, B. A.

    2012-01-01

    The South Pole-Aitken basin (SPA) is the largest of the giant impact basins in the inner Solar System, and its location on Earth s Moon makes it the most accessible. Exploration of SPA through direct collection and analysis of representative materials addresses issues as fundamental as the characteristics of the chemical reservoir from which the Moon originated, early differentiation and production of crust and development of global asymmetry, relationships between magmatic activity and internal thermal evolution, and effects of giant impact events on the terrestrial planets. Owing to its great size and superposition relationships with other lunar impact basins, SPA is the oldest and as such anchors the lunar chronology. Moreover, numerous large impact craters and basins are contained within it such that materials (rocks) of the SPA basin contain a record of the early impact chronology, one less likely to have been affected by the large, late nearside basins (e.g., Imbrium). Understanding the early basin chronology is key to deciphering the sequence and effects of early giant impact bombardment of the inner Solar System. That record exists on the Moon, and materials of the SPA basin will allow us to read that record. Knowledge of the early bombardment history will test - and may reshape - a key paradigm relating to early Solar System evolution. Did the planets form with the alignment of today, or was there a major reorientation of the giant planets that led to destabilization of asteroid orbits, and a cataclysmic bombardment of the inner Solar System hundreds of millions of years after accretion of the planets? Implications include understanding environments for early life-supporting habitats on Earth and Mars, and relationships to new observations of extra-solar planetary systems.

  4. Caspian Rapid Assessment Method: a localized procedure for assessment of wetlands at southern fringe of the Caspian Sea.

    PubMed

    Khorami Pour, Sanaz; Monavari, Seyed Masoud; Riazi, Borhan; Khorasani, Nematollah

    2015-07-01

    Although Iran is of founders of the Ramsar Convention, there is no comprehensive information available in the country on the status of wetlands in the past or at present. There is also no specific guideline for assessing the status of wetlands in the basin of the Caspian Sea as an ecosystem with unique ecological features. The main aim of this study was to develop a new procedure called "Caspian Rapid Assessment Method" (CRAM) for assessment of wetlands at southern fringe of the Caspian Sea. To this end, 16 rapid assessment methods analyzed by US EPA in 2003 were reviewed to provide an inventory of rapid assessment indices. Excluding less important indices, the inventory was short-listed based on Delphi panelists' consensus. The CRAM was developed with 6 main criteria and 12 sub-criteria. The modified method was used to assess three important wetlands of Anzali, Boojagh and Miyankaleh at the southern border of the Caspian Sea. According to the obtained results, the highest score of 60 was assigned to the Anzali Wetland. Obtaining the scores of 56 and 47, Miyankaleh and Boojagh wetlands were ranked in the next priorities, respectively. At final stage, the accuracy of CRAM prioritization values was confirmed using the Friedman test. All of the wetlands were classified into category II, which indicates destroyed wetlands with rehabilitation potentials. In recent years, serious threats have deteriorated the wetlands from class III (normal condition) to the class II.

  5. Basin modeling of Jambi Subbasin, South Sumatra, Indonesia

    SciTech Connect

    Halik, N. ); Wu, C. )

    1994-07-01

    The Jambi Subbasin is part of the South Sumatra Basin, a Tertiary back-arc basin formed by the collision between the Sundaland and Indian Plate. The Oligocene synrift Lahat Formation, and the Miocene postrift Talang Akar, Batu Raja, Gumai, and Air Benakat formations are stratigraphic intervals for potential hydrocarbon exploration. Most of the hydrocarbons have been produced from the Talang Akar and Air Benakat formations. Detailed age-depth relationship, paleobathymetry, and eustatic sea level were studied for 11 wells. Degrees of transgression and regression, and relative movement of fault blocks were predicted from rates of total and tectonic subsidence. The structural evolution of the Jambi Subbasin was reconstructed using the backstripping method. Results from the burial history modeling have helped in predicting thermal maturity, hydrocarbon generation, and structural development of the Jambi Subbasin. The timing of basement uplifting started from middle-late Miocene and reached the maximum in Pliocene-Pleistocene. Two hydrocarbon migration and accumulation mechanisms were proposed. In the depocenter, hydrocarbons were generated, migrated upward along faults, and trapped in the middle Miocene Air Benakat Formation, whereas in the basin flanks, hydrocarbons were migrated laterally from the depocenter and trapped in the Oligocene Talang Akar Formation. The methodology of this study can be applied to other subbasins in South Sumatra.

  6. Topographic-Compositional Relationships within the South Pole Aitken Basin

    NASA Astrophysics Data System (ADS)

    Lucey, P. G.; Holtzmann, J.; Blewett, D. T.; Taylor, G. J.; Hawke, B. R.

    1999-01-01

    The South Pole Aitken (SPA) Basin is an immense structure that dominates the geology of much of the farside of the Moon. Its floor is composed mostly of impact deposits, though it also has numerous relatively small regions of mare basalt. The basin floor exhibits a lower albedo and higher mafic mineral abundance than the surrounding highlands [ I ]. The origin of this mafic anomaly is a major question in lunar geology. Hypotheses for the presence of the mafic anomaly were briefly reviewed in [2] and include mare deposits mixed and obscured by basin or crater ejecta (cryptomaria), a large impact melt sheet that may have differentiated, exposed lower crustal material, and a significant component of excavated mantle. A study of mineralogy as revealed in Clementine UV-VIS imagery for limited portions of the basin found a predominantly low-Capyroxene (noritic) character [2], ruling out cryptomaria as an important contributor to the mafic enhancement. A few small cryptomaria, revealed by dark-halo impact craters and light plains units with high-FeO contents, have been found in SPA; however, it appears that extensive cryptomaria are lacking in this basin. The uniformly noritic lithology within SPA led to favor exposed lower crust or a homogenized melt sheet as the explanation for the mafic anomaly. Models of basin formation predict that a basin the size of SPA should have excavated through the entire lunar crust (assuming nonoblique impact), potentially exposing or mixing a large component of material from the mantle. Comparison of SPA floor FeO and Ti02 (derived from Clementine UV-VIS observations) and also Th (from Lunar Prospector) with model-mantle chemistries appears to be consistent with a mixture of approximately equal proportions of lower-crust and mantle material. In the present study, we examine the relationship between the basin's topography and composition in order to provide further insight on the origin of the basin floor material. Data: Clementine UV

  7. Riparian vegetation assessment of Cauvery River Basin of South India.

    PubMed

    Sunil, C; Somashekar, R K; Nagaraja, B C

    2010-11-01

    The Cauvery river basin of South India has a large phyto-floristic wealth, rightfully enough to constitute a separate phyto-geographic unit. Increase in the anthropogenic pressures within the river basin and surrounding landscapes have persistently stressed the riparian ecosystem structure adversely, besides altering its composition. The objective of this study was to examine the present status of riparian vegetation along the Cauvery river basin, in response to anthropogenic pressures. For vegetation analysis, the riparian forest coming in the middle stretch of Cauvery river was categorized into two zones, viz., forest zone covering ~54 km stretch and agroecosystem zone covering ~80 km stretch. In each zone, tree species were quantified using transects at 8-km interval. Overall tree species accounting for both forest and agroecosystem were recorded and compared. The results indicate that the mean density and basal area of trees per plot were higher in the forest zone than agroecosystem zone. The Shannon-Weiner diversity of forest zone is 4.6, which is higher than agroecosystem. In addition, species composition indicated a relatively low or poor similarity between the two zones. The vegetation density and site disturbance scores for all the study sites reveals that sand mining and grazing areas have exerted negative impact on riparian forest. The results of the present study clearly brought out the need for preparing and implementing site-specific conservation plans for riparian ecosystem.

  8. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations.

    PubMed

    Roshan, Gholamreza; Moghbel, Masumeh; Grab, Stefan

    2012-12-12

    The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively.

  9. The Caspian Sea water dynamics based on satellite imagery and altimetry

    NASA Astrophysics Data System (ADS)

    Kostianoy, Andrey G.; Lebedev, Sergey

    The Caspian Sea water dynamics is poorly known due to a lack of special hydrographic measurements. The known schemes of general circulation of the sea proposed by N.M. Knipovich in 1914-1915 and 1921, A.I. Mikhalevskiy (1931), G.N. Zaitsev (1935) and V.N. Zenin (1942) represent the basin-scale cyclonic gyres in the Middle and Southern Caspian, and no clear scheme for the shallow Northern Caspian. Later numerical models could move forward from these simple schemes of circulation to the more detailed seasonal or climatic schemes of currents, but different approaches and models give different results which significantly differ from each other (Trukhchev et al., 1995; Ibrayev et al., 2003, 2010; Popov, 2004, 2009; Knysh et al., 2008). Satellite monitoring of the Caspian Sea, we perform since 2000, is a useful tool for investigation of water dynamics in the Caspian Sea. To determine mesoscale water structure and dynamics, we used different kind of physical (SST and ice), chemical (suspended matter and water turbidity) and biological (chlorophyll concentration and algal bloom) tracers on satellite imagery. Satellite altimetry (sea level anomalies in combination with the mean dynamic level derived from numerical modeling) provides fields of currents in the whole Caspian Sea on a regular basis (every 10 days). Seasonal fields of currents derived from satellite altimetry also differ from those obtained in numerical models. Finally, we show the results of the first drifter experiment performed in the Caspian Sea in 2006-2008 in the framework of the MACE Project. Special attention is paid to the seasonal upwelling along the eastern coast of the sea, coastal currents, and a giant intrusion of warm water from the Southern to the Middle Caspian Sea.

  10. Modeling Caspian Sea water level oscillations under different scenarios of increasing atmospheric carbon dioxide concentrations

    PubMed Central

    2012-01-01

    The rapid rise of Caspian Sea water level (about 2.25 meters since 1978) has caused much concern to all five surrounding countries, primarily because flooding has destroyed or damaged buildings and other engineering structures, roads, beaches and farm lands in the coastal zone. Given that climate, and more specifically climate change, is a primary factor influencing oscillations in Caspian Sea water levels, the effect of different climate change scenarios on future Caspian Sea levels was simulated. Variations in environmental parameters such as temperature, precipitation, evaporation, atmospheric carbon dioxide and water level oscillations of the Caspian sea and surrounding regions, are considered for both past (1951-2006) and future (2025-2100) time frames. The output of the UKHADGEM general circulation model and five alternative scenarios including A1CAI, BIASF, BIMES WRE450 and WRE750 were extracted using the MAGICC SCENGEN Model software (version 5.3). The results suggest that the mean temperature of the Caspian Sea region (Bandar-E-Anzali monitoring site) has increased by ca. 0.17°C per decade under the impacts of atmospheric carbon dioxide changes (r=0.21). The Caspian Sea water level has increased by ca. +36cm per decade (r=0.82) between the years 1951-2006. Mean results from all modeled scenarios indicate that the temperature will increase by ca. 3.64°C and precipitation will decrease by ca. 10% (182 mm) over the Caspian Sea, whilst in the Volga river basin, temperatures are projected to increase by ca. 4.78°C and precipitation increase by ca. 12% (58 mm) by the year 2100. Finally, statistical modeling of the Caspian Sea water levels project future water level increases of between 86 cm and 163 cm by the years 2075 and 2100, respectively. PMID:23369617

  11. Potential Multi Canister Overpack (MCO) Cask Drop in the K West Basin South Loadout Pit

    SciTech Connect

    POWERS, T.B.

    1999-12-09

    This calculation note documents the probabilistic calculation of a potential drop of a multi-canister overpack (MCO) cask or MCO cask and immersion pail at the K West Basin south loadout pit. The calculations are in support of the cask loading system (CLS) subproject alignment of CLS equipment in the K West Basin south loadout pit.

  12. Floods of June 1965 in South Platte River basin, Colorado

    USGS Publications Warehouse

    Matthai, Howard Frederick

    1969-01-01

    Heavy, intense rains in three areas on three different days caused outstanding floods on many streams in the South Platte River basin from Plum Creek, just south of Denver, downstream to the Colorado-Nebraska State line. The flood-producing storms followed a relatively wet period, and rainfall of as much as 14 inches in a few hours was reported. The storms occurred over the Greeley-Sterling area on June 14-15, over the Plum Creek and Cherry Creek basins on June 16, and over the headwaters of Kiowa and Bijou Creeks on June 17 after heavy rains on June 15. The flood crest did not pass Julesburg, in the northeast corner of Colorado, until June 20. Previous record high discharges on many tributaries with drainage areas on the plains were exceeded, sometimes severalfold. The six principal tributaries carrying snowmelt runoff were contributing, but not significant, factors in the floods. The attenuation of the peak flow by channel storage as the flood passed through Denver was considerable; yet the peak discharge of 40,300 cfs (cubic feet per second) of the South Platte River at Denver was 1.8 times the previously recorded high of 22,000 cfs in a period of record starting in 1889. The 1965 peak would have been still higher except that all flow from Cherry Creek was stored in Cherry Creek Reservoir. Six persons were drowned, and two other deaths were attributed to the storms. The total damage amounted to $508.2 million, and about 75 percent of this occurred in the Denver metropolitan area. Descriptions of the storms and floods, detailed streamflow records, and information on damages, flood profiles, inundated areas, and flood frequency are included in this report. Several comparisons of the magnitude of the flood are made, and all indicate that an outstanding hydrologic event occurred.

  13. South Africa offers exploratory potential in variety of basins

    SciTech Connect

    Broad, D.S.; Mills, S.R. )

    1993-12-06

    While the future suspension of the oil embargo against South Africa will no doubt help revitalize the region's most powerful economy, a move away from dependence on coal as the major local energy source is also likely. This could be accomplished through regional cooperation and development were it not for the ongoing conflict in Angola, the only producer of oil and gas in the Southern African Development Community. Even with world oil prices in the doldrums, massive foreign exchange savings would result from a domestic source, and in line with world trends the possibility of harnessing the gas resources of the region is increasingly seen as a possibility. For the present, those resources remain to be defined. But ENH of Mozambique is pursuing an appraisal program for Pande field with World Bank funding, while Shell and its partners are considering possibilities of Kudu field in Namiba. And while South Africa's own national oil company, Soekor, has had limited success with its search for oil during the apartheid years, offshore F-A gas field is in production, and the potential for hydrocarbons-gas in particular--requires a great deal more investigation. The colleagues have prepared a series of articles on basins off South Africa. These articles were prepared in anticipation of the completion of political reform and of the start of a licensing round, possibly during 1994. This article draws together summaries of aspects thought to be most pertinent to petroleum exploration.

  14. Environmental settings of the South Fork Iowa River basin, Iowa, and the Bogue Phalia basin, Mississippi, 2006-10

    USGS Publications Warehouse

    McCarthy, Kathleen A.; Rose, Claire E.; Kalkhoff, Stephen J.

    2012-01-01

    Studies of the transport and fate of agricultural chemicals in different environmental settings were conducted by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program's Agricultural Chemicals Team (ACT) at seven sites across the Nation, including the South Fork Iowa River basin in central Iowa and the Bogue Phalia basin in northwestern Mississippi. The South Fork Iowa River basin is representative of midwestern agriculture, where corn and soybeans are the predominant crops and a large percentage of the cultivated land is underlain by artificial drainage. The Bogue Phalia basin is representative of corn, soybean, cotton, and rice cropping in the humid, subtropical southeastern United States. Details of the environmental settings of these basins and the data-collection activities conducted by the USGS ACT over the 2006-10 study period are described in this report.

  15. Sequence stratigraphy of the Orange basin, western offshore South Africa

    SciTech Connect

    Muntingh, A. )

    1991-03-01

    A seismic/sequence-stratigraphic framework for the siliciclastic fluvial to deepwater Cretaceous strata of the Orange basin has been constructed. Sequence-stratigraphic concepts developed by Exxon were used to interpret 10,000 km of seismic data and logs from 31 exploration boreholes within an area of 90,000 km{sup 2}. The sequence stratigraphy of the western margin exhibits 34 cyclical depositional sequences interpreted to document the response of the passive margin to cyclical changes in relative sea-level from Mid-Aptian to Late Maastrichtian times. All but one of the sequence boundaries are type 1 unconformities displaying intense erosion on the shelf and interpreted to develop during periods of rapid fall in relative sea-level. Basin-wide sequence boundaries (type 1 and 2 unconformities) were correlated with the third-order cycles of Exxon's global cycle chart utilizing SOEKOR's paleontological dating of a limited number of marine condensed sections. Higher-order cycles are recognized and best developed along the flanks of the structural arches where lower subsidence rates permitted impact of higher frequency cycles. Component depositional systems tracts inferred to have resulted from changes in relative sea level were interpreted and paleogeographic maps were constructed outlining incised valley systems on the shelf, shelf edge canyons, prograding wedges, basin floor fan, and slope fan systems. Distal marine shales and marine condensed sections provide both seal and hydrocarbon source. The chronostratigraphic and depositional framework being used to predict prospective play areas for hydrocarbon exploration on the western offshore of South Africa is also applicable to the Namibian offshore.

  16. Geodynamic evolution of southwestern Pre-Caspian region and neighboring areas of Northern Caucasus

    SciTech Connect

    Kleshchev K.; Shein, V.

    1995-08-01

    The study area includes two hydrocarbon-bearing basins. They are the southwestern Pre-Caspian basin and the eastern Northern Caucasus basin. They formed by the interaction of East-European, Aravia, Kazakhstan, Northern Caucasus, Guriev, and Ustyurt continental and sub-continental blocks. In the southwestern Pre-Caspian basin, sedimentation began at passive margins (Early-Middle Paleozoic), included salt deposition while the passive margins deformed in continental collisions (Late Paleozoic), and continued during isostatic compensation (Mesozoic-Cenozoic). Source rocks accumulated on upper Devonian to Carboniferous continental shelves and slopes. Oil and gas are trapped in sub-salt carbonate reservoirs and in clastic and carbonate rocks in complex post-salt structures. Devonian to Permian rocks, which accumulated on the margins of the Guriev continental block, are the most prospective reservoirs. The eroding Caucasus orogen produced the sediments in the Northern Caucasus basin. Clays (Oligocene-Miocene) deposited on the deep shelf in front of the orogen are the local source rocks. In the northern part of the basin, faulted anticlines are traps in the Mesozoic sequence. Traps are in thrust structures in the southern part of the basin. Carbonate and clastic rocks of the Tersko-Caspian trough are prospective in the basin.

  17. Post-breakup Basin Evolution along the South-Atlantic Margins

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2014-05-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  18. Oil and gas potential of the Pre-Caspian depression

    SciTech Connect

    Gabrieliants, G.A.; Zolotov, A.H.; Votsalebskii, E.S.; Soloviev, B.A. )

    1991-08-01

    The Pre-Caspian depression is one of the largest basin of the Soviet Union measured by sedimentary volume. The area of basin is more than 500,000 km{sup 2}, and the thickness of sedimentary mantle is 20 km in the central part of depression (Central-Pre-Caspian graben). About one-tenth of the initially recoverable hydrocarbons in the Soviet Union hook up with this basin. The sequence of sedimentary mantle of the depression is divided by salt massives of Kungarian age on subsalt (Riphean-Aptian) and supersalt (Upper Permian-Quaternary) structural-formational complexes. The first complex contain a large part (96%) of the initial recoverable hydrocarbons of the region; the remaining resources are in the supersalt complex. Deposits from Middle Devonian to Aptian age are productive in the subsalt complex. More than 30 fields of hydrocarbons (including giant fields: Astrakhan gas-condensate, Tengiz oil and gas-condensate, and Karachaganak oil and gas condensate) have been discovered in these deposits. Most commercial oil and gas reserved have been found in the carbonate reservoirs, but development of capacious terrigenous reservoirs have been predicted for the subsalt complex. Terrigenous reservoirs have received exceptional development in the supersalt complex, but large oil and gas accumulation areas are absent there. Discovered commercial oil fields (about 50) have, usually, small reservoirs in this complex. On the whole, the Pre-Caspian depression is characterized by poorly known oil and gas potential. This permits the authors to predict discoveries of new, hydrocarbon accumulations.

  19. Groundwater recharge to a sedimentary aquifer in the topographically closed Uley South Basin, South Australia

    NASA Astrophysics Data System (ADS)

    Ordens, Carlos M.; Werner, Adrian D.; Post, Vincent E. A.; Hutson, John L.; Simmons, Craig T.; Irvine, Benjamin M.

    2012-02-01

    The chloride mass balance (CMB) and water-table fluctuation (WTF) analysis methods were used to estimate recharge rates in the Uley South Basin, South Australia. Groundwater hydrochemistry and isotope data were used to infer the nature of recharge pathways and evapotranspiration processes. These data indicate that some combination of two plausible processes is occurring: (1) complete evaporation of rainfall occurs, and the precipitated salts are washed down and redissolved when recharge occurs, and (2) transpiration dominates over evaporation. It is surmised that sinkholes predominantly serve to by-pass the shallow soil zone and redistribute infiltration into the deeper unsaturated zone, rather than transferring rainfall directly to the water table. Chlorofluorocarbon measurements were used in approximating recharge origins to account for coastal proximity effects in the CMB method and pumping seasonality was accounted for in the WTF-based recharge estimates. Best estimates of spatially and temporally averaged recharge rates for the basin are 52-63 and 47-129 mm/year from the CMB and WTF analyses, respectively. Adaptations of both the CMB and WTF analyses to account for nuances of the system were necessary, demonstrating the need for careful application of these methods.

  20. Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Miller, J. R.; Mackin, G.; Lechler, P.; Lord, M.; Lorentz, S.

    2012-09-01

    The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of southeastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within both wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from the basin was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during low- to moderate flood events. The construction of a

  1. Geologic framework and petroleum systems of Cook Inlet basin, south-central Alaska

    USGS Publications Warehouse

    LePain, D.L.; Stanley, R.G.; Helmold, K.P.; Shellenbaum, D.P.

    2013-01-01

    This report provides a comprehensive overview of the stratigraphy, structure, tectonics, and petroleum systems of the Cook Inlet basin, an important oil- and gas-producing region in south-central Alaska.

  2. Drainage areas in the Vermillion River basin in eastern South Dakota

    USGS Publications Warehouse

    Benson, Rick D.; Freese, M.D.; Amundson, Frank D.

    1988-01-01

    Above-normal precipitation in the northern portion of the Vermillion River basin from 1982 through 1987 caused substantial rises in lake levels in the Lake Thompson chain of lakes, resulting in discharge from Lake Thompson to the East Fork Vermillion River. Prior to 1986, the Lake Thompson chain of lakes was thought to be a noncontributing portion of the Vermillion River basin. To better understand surface drainage, the map delineates all named stream basins, and all unnamed basins larger than approximately 10 sq mi within the Vermillion River basin in South Dakota and lists by stream name the area of each basin. Stream drainage basins were delineated by visual interpretation of contour information of U.S. Geological Survey 7 1/2 minute topographic maps. Two tables list areas of drainage basins and reaches, as well as drainage areas above gaging stations. (USGS)

  3. Can the South China Sea tell us anything about Canada Basin?

    NASA Astrophysics Data System (ADS)

    Stephenson, Randell; Li, Lu

    2016-04-01

    The Canada Basin (a sub-basin within the Amerasia Basin) and the South China Sea both preserve oceanic spreading centres and adjacent passive continental margins characterised by broad continent-ocean transition zones with hyper-extended continental crust. There are indications that hyper-extension in the South China Sea occurred mainly as a result of flow within a weak lower crustal layer and that it occurred both before and after plate break-up and the onset of ocean lithosphere formation at the sea-floor spreading axis. Available geophysical data from Canada Basin permit similar inferences. Both basins are about the same size and the oceanic segment in both is about the same size. Seafloor spreading in the South China Sea took place in the Cenozoic whereas in Canada Basin it is widely believed to have occurred during the Cretaceous. Widespread magmatism expressed as the High Arctic Large Igneous Province (HALIP) may or may not have played an intrinsic, linked, role in Canada Basin formation. No similar LIP is associated with the South China Sea although one mechanism proposed to have driven its formation is ascribed to mantle plume activity in its northernmost part. More conventionally the mechanism of opening of the South China Sea is considered to be "passive" rather than "active", related to plate reconfigurations in the southeast Asia region linked or not linked to the nearby collision of India and Eurasia and/or subduction of a "proto-South China Sea". The driving mechanism for opening of Canada Basin is poorly discussed in the literature but is generally ascribed to paleo-tectonic plate reconfigurations and subduction in the northern Pacific (Eurasia-North America plates) region in the Mesozoic. Can the South China Sea tell us anything about Canada Basin in terms of the pre-existing lithosphere of each and the geodynamic processes leading to its hyper-extension and eventual break-up?

  4. National assessment of oil and gas project; petroleum systems and assessment of the South Florida Basin

    USGS Publications Warehouse

    Pollastro, R. M.; Schenk, C.J.

    2001-01-01

    This CD-ROM contains coverages that define and outline the geographic boundaries of petroleum systems and assessment units and text that describes the geology and reasoning to support the assessment of undiscovered oil and gas resources in the South Florida Basin for a forecast period of 30 years. This assessment was performed by using the best geological information and scientific theory available to the USGS; however, the USGS did not have access to seismic survey data for the South Florida Basin.

  5. Comparative analysis of post-breakup basin evolution along the South-American and South-African margins, southern Atlantic

    NASA Astrophysics Data System (ADS)

    Strozyk, F.; Back, S.; Kukla, P. A.

    2012-04-01

    Recently, considerable attempts have been made to compare the sedimentary basin evolution and the associated tectonic framework on both sides of the South-Atlantic. However, yet there are still unresolved questions concerning the tectono-sedimentary styles of margin basin evolution that markedly differ from north to south. Amongst the most striking observations is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic margin segment on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. Adding to the heterogeneity of the system, the northernmost segment of the South Atlantic rift and salt basins is also characterized by a pronounced asymmetry, with the Brazilian margin now comprising narrower and deeper rift basins with less salt than the Congo-Gabon conjugate margin. This project deals with a large-scale comparison of this very different post-breakup tectono-stratigraphic development of the southern and northern South American and African continental margins that both record thick post-rift sedimentary successions. To gain detail of the basin margin evolution, we focus on a regional comparison between the post-breakup records archived in the large offshore southern Brazil basins (Pelotas, Santos, Campos) and the post-breakup continental margin successions of offshore Namibia (e.g. Orange Basin) and southern Angola (e.g. Kwanza Basin). A tectonic-stratigraphic comparison of representative geological transects provides a comprehensive basin-to-basin documentation of key factors influencing margin development which include the subsidence development through time, the sediment (in-)flux and storage patterns and the respective type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems). Data from the salt-prone areas offshore South America and southern

  6. Influence of basin connectivity on sediment source, transport, and storage within the Mkabela Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Miller, J. R.; Mackin, G.; Lechler, P.; Lord, M.; Lorentz, S.

    2013-02-01

    The management of sediment and other non-point source (NPS) pollution has proven difficult, and requires a sound understanding of particle movement through the drainage system. The primary objective of this investigation was to obtain an understanding of NPS sediment source(s), transport, and storage within the Mkabela Basin, a representative agricultural catchment within the KwaZulu-Natal Midlands of eastern South Africa, by combining geomorphic, hydrologic and geochemical fingerprinting analyses. The Mkabela Basin can be subdivided into three distinct subcatchments that differ in their ability to transport and store sediment along the axial valley. Headwater (upper catchment) areas are characterized by extensive wetlands that act as significant sediment sinks. Mid-catchment areas, characterized by higher relief and valley gradients, exhibit few wetlands, but rather are dominated by a combination of alluvial and bedrock channels that are conducive to sediment transport. The lower catchment exhibits a low-gradient alluvial channel that is boarded by extensive riparian wetlands that accumulate large quantities of sediment (and NPS pollutants). Fingerprinting studies suggest that silt- and clay-rich layers found within wetland and reservoir deposits of the upper and upper-mid subcatchments are derived from the erosion of fine-grained, valley bottom soils frequently utilized as vegetable fields. Coarser-grained deposits within these wetlands and reservoirs result from the erosion of sandier hillslope soils extensively utilized for sugar cane, during relatively high magnitude runoff events that are capable of transporting sand-sized sediment off the slopes. Thus, the source of sediment to the axial valley varies as a function of sediment size and runoff magnitude. Sediment export from upper to lower catchment areas was limited until the early 1990s, in part because the upper catchment wetlands were hydrologically disconnected from lower parts of the watershed during

  7. 75 FR 61414 - Basin Electric Power Cooperative: South Dakota PrairieWinds Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Rural Utilities Service Basin Electric Power Cooperative: South Dakota PrairieWinds Project AGENCY...) for the Environmental Impact Statement (EIS) for the proposed South Dakota PrairieWind Project...-megawatt wind-powered generation facility. ADDRESSES: To obtain copies of the ROD, or for...

  8. Genome Reconstruction from Metagenomic Data Sets Reveals Novel Microbes in the Brackish Waters of the Caspian Sea

    PubMed Central

    Mehrshad, Maliheh; Ghai, Rohit; Shahzadeh Fazeli, Seyed Abolhassan; Rodriguez-Valera, Francisco

    2016-01-01

    We present here the findings from a study of the microbiome of the southern basin of the Caspian Sea, the largest water body on Earth disconnected from any ocean and a brackish inland sea. By high-throughput metagenomics, we were able to reconstruct the genomes of representative microbes. The gross community structure (at the phylum level) was different from the structure of typical marine and freshwater communities in temperate open oceans, with the Caspian Sea having freshwater-like amounts of Actinobacteria and Alphaproteobacteria, while Gammaproteobacteria and Betaproteobacteria were present at intermediate levels. We assembled the genomes of several groups and provide detailed descriptions of partial genomes from Actinobacteria, Thaumarchaea, and Alphaproteobacteria. Most belonged to hitherto unknown groups, although they were related to either marine or freshwater groups. The phylogenetic placement of the Caspian genomes indicates that the organisms have multiple and separate phylogenetic origins and that they are related to organisms with both freshwater and marine lineages. Comparative recruitment from global aquatic metagenomes indicated that most Caspian microbes are endemic. However, some Caspian genomes were recruited significantly from either marine water (a member of the Alphaproteobacteria) or freshwater (a member of the Actinobacteria). Reciprocally, some genomes of other origins, such as the marine thaumarchaeon “ Candidatus Nitrosopelagicus” or the actinobacterium “Candidatus Actinomarina,” were recruited from the Caspian Sea, indicating some degree of overlap with the microbiota of other water bodies. Some of these microbes seem to have a remarkably widespread geographic and environmental distribution. PMID:26729711

  9. Metamorphism of Triassic sediments from the Dunbarton Basin, South Carolina

    SciTech Connect

    Snipes, D.S.; Warner, R.D. . Earth Sciences Dept.); Price, V. Jr. ); Thayer, P. . Geology Dept.)

    1993-03-01

    Modal analyses and microprobe studies were performed on eight core samples obtained from the US Geological Survey Well A1 324. The well is situated in the southern part of the buried Triassic Dunbarton Basin, about 1 km south of the US Department of Energy's Westinghouse Savannah River Company Site. The samples came from an interval of 407.0--413.4 m beneath the land surface. At the well site, Triassic red beds are overlain by Late Cretaceous and Tertiary sediments which have an aggregate thickness of 408 m. The sample from a depth of 407 m is a weathered, poorly sorted, clayey sandstone from the basal portion of the Late Cretaceous Cape Fear Formation. This specimen is not metamorphosed; whereas, the Triassic specimens taken from an interval of 411.6--413.4 m exhibit evidence of thermal metamorphism as well as hydrothermal alteration. In hand specimen, three of the samples (412.8--413.4 m) resemble hornfelses. These samples exhibit decussate texture. Results of modal analyses of the two deepest specimens follow: plagioclase (43-52%), quartz (9-23%), chlorite (22-29%), epidote (1-6%), hematite (3-4%), and magnetite (2-3%). Relict detrital quartz grains, especially the finer ones, are mostly angular-to-subangular and the grain boundaries show little evidence of rounding. The authors feel that hydrothermal alteration was the principal metamorphic process. This belief is supported by the fact that most of the plagioclase has undergone extensive sericitization. In addition, the presence of abundant chlorite together with a minor amount of epidote supports this interpretation. The alteration halo extends upward for 1.8 m. This interpretation is based on the observation that two Triassic arkose sandstone specimens (411.6 m, 412.2 m) contain clouded, slightly sericitized K-feldspar and plagioclase grains in a matrix of red-colored smectite.

  10. Comparative structural reconstruction of the post-breakup succession in conjugated salt and salt-free basins offshore South-America and South-Africa

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2013-04-01

    This project focuses on the post-breakup tectono-stratigraphic development of large offshore basins along the South American and African continental margins that record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. In this study we show a regional comparison between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin, etc). A sequential reconstruction of tectonic and stratigraphic elements of representative geological transects provides a comprehensive basin-to-basin documentation of the influence of key geological parameters controlling ocean and continental margin development. These include the subsidence development through time, sediment input, flux and storage patterns, salt vs. non-salt systems, carbonate-rich vs. clastics-dominated successions and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development.

  11. Spatiotemporal Assessment of Groundwater Resources in the South Platte Basin, Colorado

    NASA Astrophysics Data System (ADS)

    Ruybal, C. J.; McCray, J. E.; Hogue, T. S.

    2015-12-01

    The South Platte Basin is one of the most economically diverse and fastest growing basins in Colorado. Strong competition for water resources in an over-appropriated system brings challenges to meeting future water demands. Balancing the conjunctive use of surface water and groundwater from the South Platte alluvial aquifer and the Denver Basin aquifer system is critical for meeting future demands. Over the past decade, energy development in the basin has added to the competition for water resources, highlighting the need to advance our understanding of the availability and sustainability of groundwater resources. Current work includes evaluating groundwater storage changes and recharge regimes throughout the South Platte Basin under competing uses, e.g. agriculture, oil and gas, urban, recreational, and environmental. The Gravity Recovery and Climate Experiment satellites in conjunction with existing groundwater data is used to evaluate spatiotemporal variability in groundwater storage and identify areas of high water stress. Spatiotemporal data will also be utilized to develop a high resolution groundwater model of the region. Results will ultimately help stakeholders in the South Platte Basin better understand groundwater resource challenges and contribute to Colorado's strategic future water planning.

  12. Sample Return Mission to the South Pole Aitken Basin

    NASA Astrophysics Data System (ADS)

    Duke, M. B.; Clark, B. C.; Gamber, T.; Lucey, P. G.; Ryder, G.; Taylor, G. J.

    1999-01-01

    The South Pole Aitken Basin (SPA) is the largest and oldest observed feature on the Moon. Compositional and topographic data from Galileo, Clementine, and Lunar Prospector have demonstrated that SPA represents a distinctive major lunar terrane, which has not been sampled either by sample return missions (Apollo, Luna) or by lunar meteorites. The floor of SPA is characterized by mafic compositions enriched in Fe, Ti, and Th in comparison to its surroundings. This composition may represent melt rocks from the SPA event, which would be mixtures of the preexisting crust and mantle rocks. However, the Fe content is higher than expected, and the large Apollo basin, within SPA, exposes deeper material with lower iron content. Some of the Fe enrichment may represent mare and cryptomare deposits. No model adequately accounts for all of the characteristics of the SPA and disagreements are fundamental. Is mantle material exposed or contained as fragments in melt rock and breccias? If impact melt is present, did the vast sheet differentiate? Was the initial mantle and crust compositionally different from other regions of the Moon? Was the impact event somehow peculiar, (e.g., a low-velocity impact)? The precise time of formation of the SPA is unknown, being limited only by the initial differentiation of the Moon and the age of the Imbrium event, believed to be 3.9 b.y. The questions raised by the SPA can be addressed only with detailed sample analysis. Analysis of the melt rocks, fragments in breccias, and basalts of SPA can address several highly significant problems for the Moon and the history of the solar system. The time of formation of SPA, based on analysis of melt rocks formed in the event. would put limits on the period of intense bombardment of the Moon, which has been inferred by some to include a "terminal cataclysm." If close to 3.9 Ga, the presumed age of the Imbrium Basin, the SPA date would confirm the lunar cataclysm. This episode, if it occurred, would have

  13. HIGH-RESOLUTION SEISMIC VELOCITY AND ATTENUATION MODELS OF THE CAUCASUS-CASPIAN REGION

    SciTech Connect

    Mellors, R; Gok, R; Sandvol, E

    2007-07-10

    The southwest edge of Eurasia is a tectonically and structurally complex region that includes the Caspian and Black Sea basins, the Caucasus Mountains, and the high plateaus south of the Caucasus. Crustal and upper mantle velocities show great heterogeneity in this region and regional phases display variations in both amplitudes and travel time. Furthermore, due to a lack of quality data, the region has largely been unexplored in terms of the detailed lithospheric seismic structure. A unified high-resolution 3D velocity and attenuation model of the crust and upper mantle will be developed and calibrated. This model will use new data from 23 new broadband stations in the region analyzed with a comprehensive set of techniques. Velocity models of the crust and upper mantle will be developed using a joint inversion of receiver functions and surface waves. The surface wave modeling will use both event-based methods and ambient noise tomography. Regional phase (Pg, Pn, Sn, and Lg) Q model(s) will be constructed using the new data in combination with existing data sets. The results of the analysis (both attenuation and velocity modeling) will be validated using modeling of regional phases, calibration with selected events, and comparison with previous work. Preliminary analyses of receiver functions show considerable variability across the region. All results will be integrated into the KnowledgeBase.

  14. [The problem of invaders in the Caspian Sea in the context of the findings of new zoo- and phytoplankton species from the Black Sea].

    PubMed

    2005-01-01

    In April 2004, an expedition to the Caspian Sea discovered the species in the Middle Caspian not previously described in this sea. These species preliminary identified as Oithona similis Claus 1963, Sagitta setosa Muller 1847, and Calanus euxinus (Hulsemann) are the main representatives of edible plankton of the Black Sea; most likely they were introduced into the Caspian Sea with ballast waters of ships passing through the Volga-Don Canal. At present, it is difficult to say if these species will be established in the Caspian Sea; if so, they will clearly become a valuable food resource for planktophagous fish in the Caspian Sea. In addition, we discovered two diatom species typical for the Black Sea phytoplankton, Pseudo-nitschia seriata (Cleve) H. Peragullo and M. Peragullo and Cerataulina pelagica (Cleve) Hendey which invaded the Caspian Sea in recent years. Pseudo-nitschia seriata synthesizes a toxin (domoic acid) and can become harmful for the basin in the case of mass bloom. We discuss the problem of spontaneous invasion of alien species from the Black Sea and their effect on the Caspian ecosystem in the context of these findings.

  15. Joint Interpretation of Magnetotelluric and Gravimetric Data from the South American Paraná Basin

    NASA Astrophysics Data System (ADS)

    Santos, E. B.; Santos, H. B.; Vitorello, I.; Pádua, M. B.

    2013-05-01

    The Paraná Basin is a large sedimentary basin in central-eastern South America that extends through Brazil, Paraguay, Uruguay and Argentina. Evolved completely over the South American continental crust, this Paleozoic basin is filled with sedimentary and volcanic rocks deposited from the Silurian to the Cretaceous, when a significant basaltic effusion covered almost the entire area of the basin. A series of superposed sedimentary and volcanic rock layers were laid down under the influence of different tectonic settings, probably originated from distant collisional dynamics of continental boards that led to the amalgamation of Gondwanaland. The current boundaries of the basin can be the result of issuing erosional or of tectonic origin, such as the building up of large arches and faults. To evaluate the deep structural architecture of the lithosphere under a sedimentary basin is a great challenge, requiring the integration of different geophysical and geological studies. In this paper, we present the resulting Paraná Basin lithospheric model, obtained from processing and inversion of broadband and long-period magnetotelluric soundings along an E-W profile across the central part of the basin, complemented by a qualitative joint interpretation of gravimetric data, in order to obtain a more precise geoelectric model of the deep structure of the region.

  16. Basin fill evolution and paleotectonic patterns along the Samfrau geosyncline: the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) revisited

    NASA Astrophysics Data System (ADS)

    López-Gamundí, O. R.; Rossello, E. A.

    As integral parts of du Toit's (1927) ``Samfrau Geosyncline'', the Sauce Grande basin-Ventana foldbelt (Argentina) and Karoo basin-Cape foldbelt (South Africa) share similar paleoclimatic, paleogeographic, and paleotectonic aspects related to the Late Paleozoic tectono-magmatic activity along the Panthalassan continental margin of Gondwanaland. Late Carboniferou-earliest Permian glacial deposits were deposited in the Sauce Grande (Sauce Grande Formation) and Karoo (Dwyka Formation) basins and Falkland-Malvinas Islands (Lafonia Formation) during an initial (sag) phase of extension. The pre-breakup position of the Falkland (Malvinas) Islands on the easternmost part of the Karoo basin (immediately east of the coast of South Africa) is supported by recent paleomagnetic data, lithofacies associations, paleoice flow directions and age similarities between the Dwyka and the Lafonia glacial sequences. The desintegration of the Gondwanan Ice Sheet (GIS) triggered widespread transgressions, reflected in the stratigraphic record by the presence of inter-basinally correlatable, open marine, fine-grained deposits (Piedra Azul Formation in the Sauce Grande basin, Prince Albert Formation in the Karoo basin and Port Sussex Formation in the Falkland Islands) capping glacial marine sediments. These early postglacial transgressive deposits, characterised by fossils of the Eurydesma fauna and Glossopteris flora, represent the maximum flooding of the basins. Cratonward foreland subsidence was triggered by the San Rafael orogeny (ca. 270 Ma) in Argentina and propogated along the Gondwanan margin. This subsidence phase generated sufficient space to accommodate thick synorogenic sequences derived from the orogenic flanks of the Sauce Grande and Karoo basins. Compositionally, the initial extensional phase of these basins was characterized by quartz-rich, craton-derived detritus and was followed by a compressional (foreland) phase characterized by a paleocurrent reversal and dominance of

  17. Beyond water, beyond boundaries: spaces of water management in the Krishna river basin, South India.

    PubMed

    Venot, Jean-Philippe; Bharati, Luna; Giordano, Mark; Molle, François

    2011-01-01

    As demand and competition for water resources increase, the river basin has become the primary unit for water management and planning. While appealing in principle, practical implementation of river basin management and allocation has often been problematic. This paper examines the case of the Krishna basin in South India. It highlights that conflicts over basin water are embedded in a broad reality of planning and development where multiple scales of decisionmaking and non-water issues are at play. While this defines the river basin as a disputed "space of dependence", the river basin has yet to acquire a social reality. It is not yet a "space of engagement" in and for which multiple actors take actions. This explains the endurance of an interstate dispute over the sharing of the Krishna waters and sets limits to what can be achieved through further basin water allocation and adjudication mechanisms – tribunals – that are too narrowly defined. There is a need to extend the domain of negotiation from that of a single river basin to multiple scales and to non-water sectors. Institutional arrangements for basin management need to internalise the political spaces of the Indian polity: the states and the panchayats. This re-scaling process is more likely to shape the river basin as a space of engagement in which partial agreements can be iteratively renegotiated, and constitute a promising alternative to the current interstate stalemate.

  18. Paleogeography of the upper Paleozoic basins of southern South America: An overview

    NASA Astrophysics Data System (ADS)

    Limarino, Carlos O.; Spalletti, Luis A.

    2006-12-01

    The paleogeographic evolution of Late Paleozoic basins located in southern South America is addressed. Three major types of basins are recognized: infracratonic or intraplate, arc-related, and retroarc. Intraplate basins (i.e., Paraná, Chaco-Paraná, Sauce Grande-Colorado, and La Golondrina) are floored by continental or quasi-continental crust, with low or moderate subsidence rates and limited magmatic and tectonic activity. Arc-related basins (northern and central Chile, Navidad-Arizaro, Río Blanco, and Calingasta-Uspallata basins and depocenters along Chilean Patagonia) show a very complex tectonic history, widespread magmatic activity, high subsidence rates, and in some cases metamorphism of Late Paleozoic sediments. An intermediate situation corresponds to the retroarc basins (eastern Madre de Dios, Tarija, Paganzo, and Tepuel-Genoa), which lack extensive magmatism and metamorphism but in which coeval tectonism and sedimentation rates were likely more important than those in the intraplate region. According to the stratigraphic distribution of Late Paleozoic sediments, regional-scale discontinuities, and sedimentation pattern changes, five major paleogeographic stages are proposed. The lowermost is restricted to the proto-Pacific and retroarc basins, corresponds to the Mississippian (stage 1), and is characterized by shallow marine and transitional siliciclastic sediments. During stage 2 (Early Pennsylvanian), glacial-postglacial sequences dominated the infracratonic (or intraplate) and retroarc basins, and terrigenous shallow marine sediments prevailed in arc-related basins. Stage 3 (Late Pennsylvanian-Early Cisuralian) shows the maximum extension of glacial-postglacial sediments in the Paraná and Sauce Grande-Colorado basins (intraplate region), whereas fluvial deposits interfingering with thin intervals of shallow marine sediments prevailed in the retroarc basins. To the west, arc-related basins were dominated by coastal to deep marine conditions

  19. South China connected to north India in Gondwana: sedimentary basin and detrital provenance analyses

    NASA Astrophysics Data System (ADS)

    Yao, W.; Li, Z. X.; Li, W. X.; Li, X. H.; Yang, J. H.

    2015-12-01

    The paleoposition of South China during the Ediacaran-Silurian is important for understanding the assembly of Gondwana. We report here the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua foreland basin in South China, and discuss South China's connection with Gondwana and potential tectonic triggers for both the Wuyi-Yunkai orogeny in South China and the Bhimphedian orogeny in north India. The Nanhua basin was involved in a three-stage evolution, which are: Stage 1 (the Ediacaran-Cambrian) recording the start of tectonic subsidence with turbiditic marine clastic deposition, fed by exotic orogens outboard South China; Stage 2 (the Ordovician to earliest-Silurian) featured by migrating depocentres with dominant shallow marine to deltaic clastic deposition, fed by the local Wuyi-Yunkai orogen; and Stage 3 (the Silurian) showing the arrival of depocentre in the Yangtze Block during the waning stage of the Wuyi-Yunkai orogeny with deltaic deposition in the remanent foreland basin. Detrital zircon analyses of the Ediacaran-Silurian sandstones across the Nanhua basin reveal a prominent age population of 1100-900 Ma (with a peak age at ~980 Ma) and moderate populations of Archean-Paleozoic ages, grossly matching that of crystalline and sedimentary rocks in northern India. Zircon isotopes of the Stage 1 samples suggest three Precambrian episodes of juvenile crustal growth at 3.0 Ga, 2.5 Ga and 1.0 Ga, and a major crustal reworking at 580-500 Ma for the source areas, which are constraint to be northwestern India and its surrounding orogens. Together with other evidence, we propose that South China likely collided with northwestern India during the Gondwana assembly, generated the Bhimphedian orogeny in north India and formed two foreland basins on both the north India and South China sides. Far-field stress of the collision triggered the Ordovician-Silurian Wuyi-Yunkai orogeny in South China. The Stage 2-3 samples in the Nanhua basin of South China were shed

  20. The Effectiveness of Cattlemans Detention Basin, South Lake Tahoe, California

    USGS Publications Warehouse

    Green, Jena M.

    2006-01-01

    Lake Tahoe (Nevada-California) has been designated as an 'outstanding national water resource' by the U.S. Environmental Protection Agency, in part, for its exceptional clarity. Water clarity in Lake Tahoe, however, has been declining at a rate of about one foot per year for more than 35 years. To decrease the amount of sediment and nutrients delivered to the lake by way of alpine streams, wetlands and stormwater detention basins have been installed at several locations around the lake. Although an improvement in stormwater and snowmelt runoff quality has been measured, the effectiveness of the detention basins for increasing the clarity of Lake Tahoe needs further study. It is possible that poor ground-water quality conditions exist beneath the detention basins and adjacent wetlands and that the presence of the basins has altered ground-water flow paths to nearby streams. A hydrogeochemical and ground-water flow modeling study was done at Cattlemans detention basin, situated adjacent to Cold Creek, a tributary to Lake Tahoe, to determine whether the focusing of storm and snowmelt runoff into a confined area has (1) modified the ground-water flow system beneath the detention basin and affected transport of sediment and nutrients to nearby streams and (2) provided an increased source of solutes which has changed the distribution of nutrients and affected nutrient transport rates beneath the basin. Results of slug tests and ground-water flow modeling suggest that ground water flows unrestricted northwest across the detention basin through the meadow. The modeling also indicates that seasonal flow patterns and flow direction remain similar from year to year under transient conditions. Model results imply that about 34 percent (0.004 ft3/s) of the total ground water within the model area originates from the detention basin. Of the 0.004 ft3/s, about 45 percent discharges to Cold Creek within the modeled area downstream of the detention basin. The remaining 55 percent

  1. Potential sample sites for South Pole-Aitken basin impact melt within the Schrödinger basin

    NASA Astrophysics Data System (ADS)

    Hurwitz, Debra; Kring, David A.

    2015-10-01

    Determining the age of the South Pole-Aitken (SPA) basin ranks among the highest priorities in lunar science. This datum would constrain the timing of the oldest and largest basin-forming event on the Moon, information that is essential to any evaluation of the collisional evolution of the early Solar System. To locate material that preserves the age of SPA, a geochemical model of SPA impact melt is integrated with chemical and mineralogical analyses of the lunar surface determined from orbit. Results suggest the southern wall of Schrödinger basin contains material with the mineralogical and geochemical signatures of SPA melt and, thus, represents a candidate destination for sampling material that can constrain the age of the SPA impact.

  2. A record of Late Quaternary continental weathering in the sediment of the Caspian Sea: evidence from U-Th, Sr isotopes, trace element and palynological data

    NASA Astrophysics Data System (ADS)

    Pierret, M. C.; Chabaux, F.; Leroy, S. A. G.; Causse, C.

    2012-09-01

    This study presents combined mineralogical, chemical, isotopic (87Sr/86Sr and U-Th disequilibria series) and palynological analyses on bulk sediments and on distinct mineral phases (carbonates and clays) from a 10-m-long core drilled in the southern Caspian Sea and containing a Late Pleistocene and Early Holocene record. The data allowed identifying 1) the main variations in sedimentation, 2) the processes causing these variations, 3) the modification of erosion vs weathering, and 4) the influence of climatic and/or Caspian Sea level changes in the region since the Late Pleistocene. The chemical and mineralogical results allowed the division of the sedimentary sequence into three main units and a transition zone. The lower unit (unit U1) primarily consists of silicate and carbonate-rich detritus. Sedimentation characteristics, including observation of detritus in secular equilibrium, are relatively constant within this unit and reflect mechanical erosion in a cold climate. Unit U1 probably corresponds to a glacial period when the vegetation cover was sparse and wind and river transport of pollen were strong. Subsequently, global increase in temperatures has greatly modified the sedimentation in the Caspian Sea south basin. Biogenic sedimentation is higher in units U2 and U3, and detrital inputs varied from unit U1. Variations in detrital input are likely to be caused by decreasing aeolian contribution and by relative changes in river volumes and origins. The study of the bulk sediments, clays and carbonates reflects an increase in chemical weathering since about 10 14C ka BP ago (base of unit U2), in line with an increase in the vegetation cover. Our results suggest an evolution of continental weathering conditions in the catchment area of the Caspian Sea, from dominantly mechanical/physical erosion during the cold period to a continuous increase in weathering since the Lateglacial period, as climate improved, which illustrates the strong relation between climate

  3. Migration and isolation during the turbulent Ponto-Caspian Pleistocene create high diversity in the crustacean Paramysis lacustris.

    PubMed

    Audzijonyte, Asta; Baltrūnaitė, Laima; Väinölä, Risto; Arbačiauskas, Kęstutis

    2015-09-01

    The Ponto-Caspian brackish-water fauna inhabits estuaries and rivers of the Black, Azov and Caspian seas and is fragmented by higher salinity waters and a major interbasin watershed. The fauna is known for the high levels of endemism, complex zoogeographic histories, and as a recent source of successful invasive species. It remains debated whether the Black and Azov Sea brackish-water populations survived unfavourable Pleistocene conditions in multiple separate refugia or whether the two seas were (repeatedly) recolonized from the Caspian. Using microsatellite and mtDNA markers, we demonstrate deep among- and within-basin subdivisions in a widespread Ponto-Caspian mysid crustacean Paramysis lacustris. Five genetic clusters were identified, but their relationships did not reflect the geography of the region. The Azov cluster was the most distinct (4-5% COI divergence), despite its geographic position in the corridor between Black and Caspian seas, and may represent a new species. In the northern Black Sea area, the Dnieper cluster was closer to the Caspian cluster than to the neighbouring Danube-Dniester-Bug populations, suggesting separate colonizations of the Black Sea. Overall, the data implied a predominant gene flow from the east to the Black Sea and highlight the importance of Caspian Sea transgressions in facilitating dispersal. Yet, the presence of distinct lineages in the Black Sea points to the persistence of isolated refugial populations that have gained diagnostic differences under presumably high mutation rates and large population sizes. The unfavourable Pleistocene periods in the Black Sea therefore appear to have promoted diversification of the brackish-water lineages, rather than extirpated them.

  4. Tectonostratigraphic history of the Ediacaran-Silurian Nanhua foreland basin in South China

    NASA Astrophysics Data System (ADS)

    Yao, Wei-Hua; Li, Zheng-Xiang

    2016-04-01

    This paper presents the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua Basin in South China and explores the relationship between clastic sedimentation in the basin and evolution of the adjacent Wuyi-Yunkai orogen. Sedimentary facies in the basin comprises, in an ascending order, turbiditic marine, shallow marine, and fluvial-dominated deltaic facies, featuring a lateral migration from southeast to northwest. We interpret the Ediacaran-Silurian Nanhua Basin as a foreland basin with a three-stage evolution history. Stage 1: the Ediacaran-Cambrian stage, recording the start of tectonic subsidence with turbiditic marine siliciclastic deposition, fed by exotic orogens outboard South China; Stage 2: the Ordovician to earliest-Silurian stage, characterized by a migrating depocenter with dominant shallow marine and deltaic siliciclastic deposition, fed by the local and northwestward propagating Wuyi-Yunkai orogen; Stage 3: the Silurian stage, showing the arrival of depocenter in the Yangtze Block during the waning stage of the orogeny with deltaic deposition in the remanent foreland basin. The Wuyi-Yunkai orogen remained the dominant sedimentary source region during Stage 3. Stage 1 was likely related to the collision of the South China Block toward northern India during the assembly of Gondwana, whereas Stages 2 and 3 recorded sedimentation during the northwestward propagation and subsequent orogenic root delamination/collapse of the Wuyi-Yunkai orogen, respectively. The Wuyi-Yunkai orogeny in South China is interpreted to have resulted from the far-field stress of the collision between South China and Indian Gondwana.

  5. Sedimentary basins on the connugate margins of South America and Africa

    SciTech Connect

    Moore, G.T. )

    1990-05-01

    An Early Cretaceous spreading system formed the South Atlantic by separating South America from Africa along two subparallel major transform fault systems. The distribution of major sedimentary depocenters is controlled by the complex interplay of two factors: the late Mesozoic-Cenozoic cycle of sea-floor spreading and the legacy of a Precambrian collage of ancient cores that comprised western Gondwana. Three spreading modes created this configuration: rift, transform, and subduction. Each produces a different geometry and tectonic framework for the accumulation of sediment. Rifted margins (60%) contain basins that are elongate, form with their depocenter axes inboard of the ocean-continent transition, and rest on a tectonically complex, foundered basement. Transform margins have abrupt ocean-continent transitions. Such margins (30%) may be sediment starved or contain a thick sedimentary section controlled by the volcanic ridges of transform faults. Off Tierra del Fuego, Burdwood Bank is bounded on the north by a fossil (aseismic) subduction zone. The associated basin is an elongate, deformed accretionary prism of sediments on a gently dipping, faulted oceanic plate. The South Atlantic margins are divisible into 68 basins or segments that collectively contain over 33 {times} 106 km{sup 3} of syn- and postbreakup sediments. The South American margin contains 22 {times} 10{sup 6} km{sup 3} in 46 basins, and the African margin, 11 {times} 10{sup 6} km{sup 3} in 22 basins. Over 65% of the basins have a sediment column greater than 5 km with some depocenters that locally exceed 10 km. The source rock quality and character vary along both margins. The top of the oil generation window averages about 3.3 km; however, due to differing thermal histories, individual basins can depart significantly from this average.

  6. A basin on an unstable ground: Correlation of the Middle Archaean Moodies Basin, Barberton Greenstone Belt, South Africa

    NASA Astrophysics Data System (ADS)

    Ohnemueller, Frank; Heubeck, Christoph; Kirstein, Jens; Gamper, Antonia

    2010-05-01

    The 3.22 Ga-old Moodies Group, representing the uppermost part of the Barberton Supergroup of the Barberton Greenstone Belt (BGB), is the oldest well-exposed, relatively unmetamorphosed, quartz-rich sedimentary unit on Earth. Moodies facies (north of the Inyoka Fault) were thought to be largely of alluvial, fluvial, deltaic or shallow-marine origin (Anhaeusser, 1976; Eriksson, 1980; Heubeck and Lowe, 1994) and in its upper part syndeformational. However, units can only locally be correlated, and the understanding of the interplay between Moodies sedimentation and deformation is thus limited. We mapped and measured Moodies units in the northern BGB. They partly consist of extensive turbiditic deepwater deposits, including graded bedding, flame structures, and slumped beds, interbedded with jaspilites. These contrast with shallow-water environments, south-facing progressive unconformities and overlying alluvial-fan conglomerates along the northern margin of the Saddleback Syncline further south. The palaeogeographic setting in which late BGB deformation was initiated therefore appears complex and cannot be readily explained by a simple southward-directed shortening event. In order to constrain Moodies basin setting before and during late-Moodies basin collapse, we correlated ~15 measured sections in the northern and central BGB. Most units below the Moodies Lava (MdL, ca. 3230.6+-6 Ma) can be correlated throughout although facies variations are apparent. Above the Moodies Lava, coarse-grained units can only be correlated through the Eureka Syncline and the Moodies Hills Block but not with the Saddleback Syncline. Fine-grained and jaspilitic units can be correlated throughout the northern BGB. Moodies below-wavebase deposition occurred largely north of the Saddleback Fault. The observations are consistent with a pronounced basin compartmentalization event following the eruption of the MdL which appeared to have blanketed most of the Moodies basin(s) in middle Moodies

  7. South Pole-Aitken Basin: Evidence for Post-Basin Resurfacing from Lunar Orbiter Laser Altimeter (LOLA) Data

    NASA Astrophysics Data System (ADS)

    Head, J. W.; Fassett, C.; Kadish, S.; Smith, D. E.; Zuber, M. T.; Neumann, G. A.; Mazarico, E.

    2010-12-01

    The lunar farside South Pole-Aitken Basin is the largest and oldest documented basin on the Moon and is thus of interest from the point of view of the scale of production of impact melt at large basin-event sizes and its ring structure and potential depth of sampling at such a large diameter. We used new LOLA data from the Lunar Reconnaissance Orbiter 1) to characterize the basin interior topography, 2) to assess the nature of the nearby and relatively pristine Orientale basin and compare it to the SPA interior, and 3) to compile a new global crater database of all lunar craters ≥20 km in diameter and to assess the population of impact craters superposed on the SPA interior and exterior. We find that impact crater size-frequency distribution plots show that the exterior of the SPA basin is similar to the most heavily cratered regions of the Moon, but that the interior of the basin has a deficiency of craters in the 20-64 km diameter crater range. One interpretation of these data is that some resurfacing process (or processes) has modified the superposed crater population. Among the candidates are 1) impact crater proximity weathering/degradation by adjacent (e.g., Apollo) and nearby (e.g., Orientale) impact basin ejecta, 2) volcanic resurfacing by early non-mare volcanism, cryptomaria and/or maria, and 3) viscous relaxation removing crater topography. We consider viscous relaxation of crater topography to be the least likely due to the wavelength dependence of the process (rim-crests should be preserved and thus detected in our crater counts). Careful analysis of the impact ejecta thickness radial decay suggests that it is an important resurfacing mechanism within a basin radius from the rim crest, but is unlikely to be sufficient to explain the observed deficiency. Morphometric analysis of impact craters, modeling, and simulations of volcanic flooding suggest that the deficiency may be related to the patchy distribution of cryptomaria, suspected from mineralogic

  8. Application of Basin Morphometry Laws in catchments of the south-western quadrangle of south-eastern Nigeria

    NASA Astrophysics Data System (ADS)

    Aisuebeogun, A. O.; Ezekwe, I. C.

    2013-09-01

    The relationship between process and form has been at the core of research in fluvial geomorphology. Form-process relationships of a natural river basin are strongly influenced by its hydrologic and sedimentologic processes as basin morphometric properties of length, shape, and relief, change in response to various hydrologic stimuli from the environment, but usually in line with well established laws. In the four river basins (Orashi, Otamiri, Sombreiro, New Calabar) examined in this study, however, empirical evidence does not conform neatly with theoretical postulates. Remarkable variations are noted in the morphometric properties of the catchments, when compared with established morphometric laws. The most varied in conformity are the Orashi and New Calabar basins, although the Sombreiro and Otamiri catchments also show some level of variation. Prime explanation for the morphometric and topographic non-conformity is caused by the nature of surficial material and the profoundly shallow relief of much of the study area, especially the alluvial flood and deltaic plains to the south and south-west of the study area.

  9. Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam

    SciTech Connect

    Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J.

    1996-12-31

    Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motions have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.

  10. Structure, stratigraphy and petroleum geology of the south east Nam Con Son Basin, offshore Vietnam

    SciTech Connect

    Fraser, A.J.; Matthews, S.J.; Lowe, S.; Todd, S.P.; Simon, P. Peel, F.J. )

    1996-01-01

    Recent exploration of the south east Nam Con Son Basin, offshore Vietnam, by BP in alliance with Statoil has involved acquisition of new seismic and well data. These new data have allowed re-evaluation of the tectono-stratigraphic development and petroleum geology, and have provided additional constraints on the regional tectonic evolution. The offshore Vietnamese basins have evolved in response to the complex relative motions of Indochina, Peninsular Malaysia, Borneo and the South China Sea during the Cenozoic. On the regional scale these motions have been accommodated by strike-slip fault development, rifting and contraction. In the Nam Con Son Basin these motions have interacted in different ways from the Palaeogene to recent. Two rifting episodes are recognized; a Palaeogene phase dominated by E-W trending extensional faults, and a Miocene phase dominated by N-S to NE-SW trending faults. The structural evolution is complicated by a pulse of mild contraction during the Middle Miocene. The sedimentary fill of the basin evolves from continental fluvio-lacustrine in the Palaeogene through to fully marine following the second phase of rifting in the Miocene. This pulsed structural and stratigraphic evolution has resulted in basinwide deposition of source, reservoir and seal facies, and produced a variety of potential trapping styles. This paper describes the hydrocarbon habitat of the south east Nam Con Son Basin within the context of the regional tectono-stratigraphic model.

  11. Hydrogeochemical and isotopic investigations of the Han River basin, South Korea

    NASA Astrophysics Data System (ADS)

    Ryu, Jong-Sik; Lee, Kwang-Sik; Chang, Ho-Wan

    2007-10-01

    SummaryThe Han River, the largest river in South Korea draining approximately 26,000 km 2, comprises two major tributaries: the North and the South Han Rivers. Seasonal and spatial variations in the major ion chemistry and isotope compositions of the Han River were monitored for one year at 14-23 locations, covering about 80% of the entire drainage basin. Compared to the South Han River (SHR), the North Han River (NHR) was much lower in total dissolved solids (TDS), Sr, and major ion concentrations, but higher in Si concentration, δ 34S SO 4 values, and 87Sr/ 86Sr ratios. These observations suggest strong influence of prevailing rock types in the drainage basins on the chemical and isotopic compositions of the river waters. These are silicate rocks in the NHR basin and carbonate rocks in the SHR basin. The headwaters of the NHR basin, where several flood control dams have been constructed, show enrichment in deuterium and oxygen-18, indicating evaporative loss. The δ 34S SO 4 data suggest dissolved sulfates in the NHR and SHR are mostly derived from atmospheric deposition, and variable mixtures of atmospheric deposition and sulfide oxidation, respectively. The 87Sr/ 86Sr ratios are much higher in the NHR (0.71793-0.72722) than in the SHR (0.71495-0.71785) with one exception, indicating weathering of Precambrian and Mesozoic granitic rocks and marine carbonates, respectively.

  12. Caspian Sea MODU refurbished to western standards

    SciTech Connect

    Prince, P.K.; Yenzer, D.E.

    1997-05-05

    A consortium of eleven companies acquired and refurbished the semisubmersible drilling unit Kaspmorneft for drilling in the Azerbaijani sector of the Caspian Sea. This was the first such acquisition and refurbishment project in the region. The project cost $40 million and took 12 months. The paper discusses the Caspian Sea potential, existing fleet, option evaluation, contracting philosophy, drilling contractor selection, inspection survey, project scope, planned work, actual work, schedule, plan execution, implementation, work force, training, safety, environmental concerns, quality management, subcontractors, work site, logistics, and work completion.

  13. 72. (Credit LSU) Aerator in settling basin south of McNeil ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    72. (Credit LSU) Aerator in settling basin south of McNeil Pumping Station c1907. (Louisiana State University in Shreveport Archives, post card collection) - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  14. Watershed scale response to climate change--South Fork Flathead River Basin, Montana

    USGS Publications Warehouse

    Chase, Katherine J.; Hay, Lauren E.; Markstrom, Steven L.

    2012-01-01

    Fourteen basins for which the Precipitation Runoff Modeling System has been calibrated and evaluated were selected as study sites. Precipitation Runoff Modeling System is a deterministic, distributed parameter watershed model developed to evaluate the effects of various combinations of precipitation, temperature, and land use on streamflow and general basin hydrology. Output from five General Circulation Model simulations and four emission scenarios were used to develop an ensemble of climate-change scenarios for each basin. These ensembles were simulated with the corresponding Precipitation Runoff Modeling System model. This fact sheet summarizes the hydrologic effect and sensitivity of the Precipitation Runoff Modeling System simulations to climate change for the South Fork Flathead River Basin, Montana.

  15. Andean Basins Morphometry: Assesing South American Large Rivers' Source Areas

    NASA Astrophysics Data System (ADS)

    Bean, R. A.; Latrubesse, E. M.

    2014-12-01

    Presently there are no regional-scale morphometric analyses of Andean fluvial basins. Therefore, we created a continental-scale database of these basins. Our data covers over an area 1,000,000 km2 of the Andes, from Venezuela to Argentina. These basins are the source of some of the largest rivers in the world including the Amazon, Orinoco, Parana, and Magdalena. Morphometric parameters including shape factor, relief ratio, longitudinal profiles and different indices of basin elevation were calculated based on the CGIAR SRTM 4.1 DEM (~90 m resolution). FAO Hydrosheds were used to segment the DEM by major catchment and then manually cut at the Andean zone. In the North and Central Andes, this produced over 500,000 subcatchments, which we reduced to 619 by setting minimum catchment area to 100 km2. We then integrate lithologic data from DNPM geologic data. Our results indicate that sedimentary lithologies dominate Central Andean catchments (n=268,k=4), which cover an area 767,00 km2, while the Northern Andean catchments (covering 350,000 km2) are more varied, dominated by volcanics in the Pacific (n=78), a sedimentary (48%) dominant mix in the Caribbean (n=138) and 60% sedimentary in the Amazon-Orinoco subregion catchments (n=138). Elevation averages are smallest in the north Andes and average maximum elevations (6,026 m) in the Argentinian catchments (n=65) of the Central Andes are the highest. Shape factors range from 0.49 to 0.58 in the North and 0.52 to 0.58 in the Central Andes. There are clear differences in all categories between region and subregion, but that difference does not hinge on a single morphometric or geologic parameter. Morphometric parameters at a watershed scale (listed in Table) are analyzed and hydrologic data from gauging stations throughout the Andes (n=100) are used to compare morphometric parameters with lithology and characteristics from the basin hydrograph (peak discharge timing, minimum and maximum discharge, and runoff).

  16. Ozone trends in California`s South Coast Air Basin, 1976--1996

    SciTech Connect

    Cohanim, S.; Cassmassi, J.; Bassett, M.

    1998-12-31

    The South Coast Air Basin (Basin) of Southern California exhibits the worst air quality in the nation, as measured by the annual number of days exceeding the 1-hour National Ambient Air Quality Standard (NAAQS) for ozone. Hourly pollutant concentration data collected by the South Coast Air Quality Management District`s air monitoring network are compared to the existing 1-hour and new 8-hour federal ozone ambient air quality standards to depict ozone trends and compliance in the Basin. Results of trend analyses for the different areas of the Basin are presented for the 1-hour and 8-hour standards, and the relative stringency of the existing and new federal standards is examined. Based on an analysis of the effect of the recently adopted federal standard on ozone compliance in the Basin, ozone concentrations exceed the new federal 8-hour standard level more often than the existing 1-hour standard in most locations. However, examination of the trends in design values for the 1-hour and 8-hour ozone standards suggests that for most locations in the Basin the new standard probably should not be significantly more difficult to attain than the existing standard. The weather-adjusted ozone trend analysis in the Basin confirms the fact that the downtrends in ozone concentrations and number of days exceeding standards are real and independent of annual variation in weather. An analysis of weekday/weekend differences in exceedances for the existing 1-hour and new 8-hour ozone standards show a higher number of days exceeding both standards on weekends for most locations in the Basin, with differences being more evident in the 1990s than in the late 1970s and 1980s

  17. Rock types of South Pole-Aitken basin and extent of basaltic volcanism

    USGS Publications Warehouse

    Pieters, C.M.; Head, J. W.; Gaddis, L.; Jolliff, B.; Duke, M.

    2001-01-01

    The enormous pre-Nectarian South Pole-Aitken (SPA) basin represents a geophysically and compositionally unique region on the Moon. We present and analyze the mineralogical diversity across this basin and discuss the implications for basin evolution. Rock types are derived from Clementine multispectral data based on diagnostic characteristics of ferrous absorptions in fresh materials. Individual areas are characterized as noritic (dominated by low-Ca pyroxene), gabbroic/basaltic (dominated by high-Ca pyroxene), feldspathic (<3-6% FeO), and olivine-gabbro (dominated by high-Ca pyroxene and olivine). The anorthositic crust has effectively been removed from the interior of the basin. The style of volcanism within the basin extends over several 100 Myr and includes mare basalt and pyroclastic deposits. Several areas of ancient (pre-Orientale) volcanism, or cryptomaria, have also been identified. The nonmare mafic lithology that occurs across the basin is shown to be noritic in composition and is pervasive laterally and vertically. We interpret this to represent impact melt/breccia deposits derived from the lower crust. A few localized areas are identified within the basin that contain more diverse lithologies (gabbro, olivine-gabbro), some of which may represent material from the deepest part of the lower crust and perhaps uppermost mantle involved in the SPA event. Copyright 2001 by the American Geophysical Union.

  18. Preliminary interpretation of industry two-dimensional seismic data from Susitna Basin, south-central Alaska

    USGS Publications Warehouse

    Lewis, Kristen A.; Potter, Christopher J.; Shah, Anjana K.; Stanley, Richard G.; Haeussler, Peter J.; Saltus, Richard W.

    2015-07-30

    The eastern seismic lines show evidence of numerous short-wavelength antiforms that appear to correspond to a series of northeast-trending lineations observed in aeromagnetic data, which have been interpreted as being due to folding of Paleogene volcanic strata. The eastern side of the basin is also cut by a number of reverse faults and thrust faults, the majority of which strike north-south. The western side of the Susitna Basin is cut by a series of regional reverse faults and is characterized by synformal structures in two fault blocks between the Kahiltna River and Skwentna faults. These synforms are progressively deeper to the west in the footwalls of the east-vergent Skwentna and northeast-vergent Beluga Mountain reverse faults. Although the seismic data are limited to the south, we interpret a potential regional south-southeast-directed reverse fault striking east-northeast on the east side of the basin that may cross the entire southern portion of the basin.

  19. Post-breakup Basin Evolution along the South-Atlantic Margins in Brazil and Angola/Namibia

    NASA Astrophysics Data System (ADS)

    Kukla, P. A.; Strozyk, F.; Back, S.

    2013-12-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  20. Imaging the South Pole-Aitken basin in backscattered neutral hydrogen atoms

    NASA Astrophysics Data System (ADS)

    Vorburger, A.; Wurz, P.; Barabash, S.; Wieser, M.; Futaana, Y.; Bhardwaj, A.; Asamura, K.

    2015-09-01

    The lunar surface is very efficient in reflecting impinging solar wind ions as energetic neutral atoms (ENAs). A global analysis of lunar hydrogen ENAs showed that on average 16% of the solar wind protons are reflected, and that the reflected fraction can range from less than 8% to more than 24%, depending on location. It is established that magnetic anomalies reduce the flux of backscattered hydrogen ENAs by screening-off a fraction of the impinging solar wind. The effects of the surface properties, such as porosity, roughness, chemical composition, and extent of weathering, were not known. In this paper, we conduct an in-depth analysis of ENA observations of the South Pole-Aitken basin to determine which of the surface properties might be responsible for the observed variation in the integral ENA flux. The South Pole-Aitken basin with its highly variable surface properties is an ideal object for such studies. It is very deep, possesses strikingly elevated concentrations in iron and thorium, has a low albedo and coincides with a cluster of strong magnetic anomalies located on the northern rim of the basin. Our analysis shows that whereas, as expected, the magnetic anomalies can account well for the observed ENA depletion at the South Pole-Aitken basin, none of the other surface properties seem to influence the ENA reflection efficiency. Therefore, the integral flux of backscattered hydrogen ENAs is mainly determined by the impinging plasma flux and ENA imaging of backscattered hydrogen captures the electrodynamics of the plasma at the surface. We cannot exclude minor effects by surface features. We create two maps of surface reflected ENAs at the South Pole-Aitken basin. We compare these ENA maps to elevation, albedo, composition and magnetic field maps. The ENA maps only significantly correlate with the magnetic field map. ENA imaging captures solely the electrodynamics of the plasma at the surface.

  1. Surveying the South Pole-Aitken basin magnetic anomaly for remnant impactor metallic iron

    USGS Publications Warehouse

    Cahill, Joshua T.S.; Hagerty, Justin J.; Lawrence, David M.; Klima, Rachel L.; Blewett, David T.

    2014-01-01

    The Moon has areas of magnetized crust ("magnetic anomalies"), the origins of which are poorly constrained. A magnetic anomaly near the northern rim of South Pole-Aitken (SPA) basin was recently postulated to originate from remnant metallic iron emplaced by the SPA basin-forming impactor. Here, we remotely examine the regolith of this SPA magnetic anomaly with a combination of Clementine and Lunar Prospector derived iron maps for any evidence of enhanced metallic iron content. We find that these data sets do not definitively detect the hypothesized remnant metallic iron within the upper tens of centimeters of the lunar regolith.

  2. Seismic stratigraphy and stratigraphic modelling of the South-eastern German Molasse Basin

    SciTech Connect

    Aigner, T.; Jin, J.; Luterbacher, P.

    1995-08-01

    Although the German Molasse Basin can be regarded as a mature hydrocarbon province, no regional sequence stratigraphic analysis has been carried out so far. We have studied seismic lines and well data from the region between the Isar and Inn rivers (SE Germany) that have been generously supplied by German oil companies (DEE, BEB, Mobil, RWE-DEA and Wintershall). Initial work indicates that five major seismic sequences within three main depositional cycles are developed. The Alpine thrust belt to the south serves as the primary sediment source in the foreland basin. However, sedimentary infill mainly took place parallel to the basin axis. Our analysis suggests that the stratigraphic development of the Molasse Basin was mainly controlled by eustatic sea-level changes which caused the shoreline to shift in the W-E direction. The shifting of the depocenter axis in a N-S direction was controlled by the tectonic evolution of the thrust belt. The sea-level curve determined by seismic stratigraphy and well-derived subsidence curves have been used as input parameters for stratigraphic modelling, using the programs GeoMOD and PHIL. Basin-fill simulations with PHIL are in good agreement with the main features of the sequence stratigraphy and the distribution of the systems tracts observed in the study area. The qualitative sea-level curve for the German Molasse Basin derived from the seismostratigraphic analysis could be quantified by the stratigraphic exercises.

  3. Geomorphic Terrains and Evidence for Ancient Volcanism within Northeastern South Pole-Aitken Basin

    NASA Technical Reports Server (NTRS)

    Petro, Noah; Mest, Scott C.; Teich, Yaron

    2010-01-01

    The interior of the enigmatic South Pole-Aitken Basin has long been recognized as being compositionally distinct from its exterior. However, the source of the compositional anomaly has been subject to some debate. Is the source of the iron-enhancement due to lower-crustal/upper-mantle material being exposed at the surface, or was there some volume of ancient volcanism that covered portions of the basin interior? While several obvious mare basalt units are found within the basin and regions that appear to represent the original basin interior, there are several regions that appear to have an uncertain origin. Using a combination of Clementine and Lunar Orbiter images, several morphologic units are defined based on albedo, crater density, and surface roughness. An extensive unit of ancient mare basalt (cryptomare) is defined and, based on the number of superimposed craters, potentially represents the oldest volcanic materials within the basin. Thus, the overall iron-rich interior of the basin is not solely due to deeply derived crustal material, but is, in part due to the presence of ancient volcanic units.

  4. Hydrocarbon potential of the Lamu basin of south-east Kenya

    SciTech Connect

    Nyagah, K.; Cloeter, J.J.; Maende, A.

    1996-12-31

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  5. Hydrocarbon potential of the Lamu basin of south-east Kenya

    SciTech Connect

    Nyagah, K.; Cloeter, J.J.; Maende, A. )

    1996-01-01

    The Lamu basin occupies the coastal onshore and offshore areas of south-east Kenya. This fault bounded basin formed as a result of the Paleozoic-early Mesozoic phase of rifting that developed at the onset of Gondwana dismemberment. The resultant graben was filled by Karroo (Permian-Early Jurassic) continental siliciclastic sediments. Carbonate deposits associated with the Tethyan sea invasion, dominate the Middle to Late Jurassic basin fill. Cessation of the relative motion between Madagascar and Africa in the Early Cretaceous, heralded passive margin development and deltaic sediment progradation until the Paleogene. Shallow seas transgressed the basin in the Miocene when another carbonate regime prevailed. The basin depositional history is characterized by pulses of transgressive and regressive cycles, bounded by tectonically enhanced unconformities dividing the total sedimentary succession into discrete megasequences. Source rock strata occur within Megasequence III (Paleogene) depositional cycle and were lowered into the oil window in Miocene time, when the coastal parts of the basin experienced the greatest amount of subsidence. The tectono-eustatic pulses of the Tertiary brought about source and reservoir strata into a spatial relationship in which hydrocarbons could be entrapped. A basement high on the continental shelf has potential for Karroo sandstone and Jurassic limestone reservoirs. Halokinesis of Middle Jurassic salt in Miocene time provides additional prospects in the offshore area. Paleogene deltaic sands occur in rotated listric fault blacks. A Miocene reef Play coincides with an Eocene source rock kitchen.

  6. Mid-Pleistocene Acheulean-like stone technology of the Bose basin, South China.

    PubMed

    Yamei, H; Potts, R; Baoyin, Y; Zhengtang, G; Deino, A; Wei, W; Clark, J; Guangmao, X; Weiwen, H

    2000-03-01

    Stone artifacts from the Bose basin, South China, are associated with tektites dated to 803,000 +/- 3000 years ago and represent the oldest known large cutting tools (LCTs) in East Asia. Bose toolmaking is compatible with Mode 2 (Acheulean) technologies in Africa in its targeted manufacture and biased spatial distribution of LCTs, large-scale flaking, and high flake scar counts. Acheulean-like tools in the mid-Pleistocene of South China imply that Mode 2 technical advances were manifested in East Asia contemporaneously with handaxe technology in Africa and western Eurasia. Bose lithic technology is associated with a tektite airfall and forest burning.

  7. Mid-Pleistocene Acheulean-like stone technology of the Bose basin, South China.

    PubMed

    Yamei, H; Potts, R; Baoyin, Y; Zhengtang, G; Deino, A; Wei, W; Clark, J; Guangmao, X; Weiwen, H

    2000-03-01

    Stone artifacts from the Bose basin, South China, are associated with tektites dated to 803,000 +/- 3000 years ago and represent the oldest known large cutting tools (LCTs) in East Asia. Bose toolmaking is compatible with Mode 2 (Acheulean) technologies in Africa in its targeted manufacture and biased spatial distribution of LCTs, large-scale flaking, and high flake scar counts. Acheulean-like tools in the mid-Pleistocene of South China imply that Mode 2 technical advances were manifested in East Asia contemporaneously with handaxe technology in Africa and western Eurasia. Bose lithic technology is associated with a tektite airfall and forest burning. PMID:10698732

  8. Physical characteristics of stream subbasins in the Blue Earth River Basin, south-central Minnesota and north-central Iowa

    USGS Publications Warehouse

    Lorenz, D.L.; Payne, G.A.

    1992-01-01

    This report presents data describing the physical characteristics of stream basins upstream from selected points on streams in the Blue Earth River basin, located in south-central Minnesota and north-central Iowa. The physical characteristics are the drainage area of the basin, the percentage area of the basin covered only by lakes, the percentage area of the basin covered by both lakes and wetlands, the main-channel length, and the mainchannel slope. The points on the stream include outlets of subbasins of at least five square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey gaging stations.

  9. Regional elemental abundances within South Pole-Aitken basin as measured with lunar prospector gamma-ray spectrometer data.

    SciTech Connect

    Lawrence, David J. ,; Pieters, Carlé M.; Elphic, R. C.; Gasnault, O. M.; Prettyman, T. H.; Feldman, W. C.

    2003-01-01

    South Pole-Aitken (SPA) basin has been a target of intense study since it is one of the largest impact basins in the solar system. It is thought that SPA basin excavated deep into the lunar crust and possibly even the mantle. Such conclusions have been supported by the observed mafic and thorium composition anomalies seen across the entire basin. One of the major goals of lunar and planetary science has been to measure and understand the composition of the non-mare materials within SPA basin. It is expected that this information will help to increase our understanding of the formation and differentiation processes that occurred early on the Moon.

  10. Environmental inequality: Air pollution exposures in California's South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Marshall, Julian D.

    Environmental inequality is quantified here using linear regression, based on results from a recent mobility-based exposure model for 25,064 individuals in California's South Coast Air Basin [Marshall et al., 2006. Inhalation intake of ambient air pollution in California's South Coast Air Basin. Atmospheric Environment 40, 4381-4392]. For the four primary pollutants studied (benzene, butadiene, chromium particles, and diesel particles), mean exposures are higher than average for people who are nonwhite, are from lower-income households, and live in areas with high population density. For ozone (a secondary pollutant), the reverse holds. Holding constant attributes such as population density and daily travel distance, mean exposure differences between whites and nonwhites are 16-40% among the five pollutants. These findings offer a baseline to compare against future conditions or to evaluate the impact of proposed policies.

  11. Mesozoic tectonically driven climatic partitioning of the south Junggar and north Tarim basins, northwest China

    SciTech Connect

    Hendrix, M.S.; Graham, S.A.; Brassell, S.C. )

    1991-03-01

    Detailed basin analysis of Mesozoic strata exposed in the south Junggar and north Tarim foreland basin Mesozoic depocenters, northwest China, has documented periodic structural reactivation of the intervening Tian Shan during that era. Coarse alluvial pulses, contained in an otherwise relatively fine-grained section of fluvial lacustrine sediments, were shed off both the north and south flanks of the Tian Shan during the Late Triassic, Latest Jurassic, and late Cretaceous. The lofty modern Tian Shan and associated rain shadow cast over the Tarim basin to the south reflect deformation associated with the early Cenozoic Himalayan collision; so too were the two basins climatically partitioned during the Mesozoic in response to relief produced by orogenesis. During prolonged episodes of relative tectonic quiescence, it appears that Tian Shan relief was too low to confine moisture to the windward side of the range. Most notable is the Middle Jurassic section that is dominated in both basins by a relatively fine-grained series of organic-rich, meandering fluvial, and lacustrine sediments. Pyrolytic analyses of organic-rich mudstones associated with these sediments document high H.I. kerogens, suggesting algal-dominated organic matter typical of anoxic lacustrine settings. However, detailed GC-MS biomarker analysis of the alipaphatic fraction also suggests substantial input from higher land plants in addition to algal sources. Not only are n-alkane distributions typically dominated by high molecular weight compounds with an odd-over-even preference typical of higher land plants, but the abundance of specific diterpenoid biomarker compounds strongly suggests the development of widespread coniferous forests on either side of the range during the Middle Jurassic.

  12. An assessment of metal contamination in coastal sediments of the Caspian Sea.

    PubMed

    de Mora, Stephen; Sheikholeslami, Mohammad Reza; Wyse, Eric; Azemard, Sabine; Cassi, Roberto

    2004-01-01

    An assessment of marine pollution due to metals was made in the Caspian Sea based on coastal sediment collected in Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. Despite the high carbonate content, the distribution of most metals was largely controlled by terrigenous inputs. Several metals (As, Cr, Ni) exhibited concentrations that exceed sediment quality guidelines. Such metals have a high natural background but anthropogenic activities, notably mining, may further enhance concentrations. This would explain hot spots for Cu and Zn in Azerbaijan and Iran, and Cr at the mouth of the Ural River in Kazakhstan. Contamination by Hg was observed to the south of Baku Bay, Azerbaijan. Some anomalously high concentrations of Ba in the central Caspian are probably from offshore drilling operations, but the elevated U concentrations (up to 11.1 microg g(-1)) may be natural in origin. Several metals (Ag, Cd, Pb) have relatively low levels that pose no environmental concerns. PMID:14725876

  13. Cenozoic tectonic evolution and petroleum exploration in Perl River Mouth basin, South China Sea

    SciTech Connect

    Chi Yukun; Xu Shice )

    1990-06-01

    The Pearl River Mouth basin is a large Cenozoic continental margin basin that is rich in hydrocarbon potential. Fluvial-lake sequences were deposited before Oligocene, but all were covered by Miocene marine clastic and carbonate rocks. Both paleo-Pearl River delta system and reef/bank carbonate system were widely developed. At the early stage of the evolution, two subsidence belts and one uplift between them distributed in NE regional direction; grabens occurred in the north belt and depressions in the south belt. Tectonic movement was stronger in the east than the west. The main production zones have been drilled both in Miocene sandstone and carbonate rocks. As the exploration activities are developing, the basin will be one of the most significant China offshore oil production areas.

  14. Recognition of relict Mesozoic Dongsha Basin in the northern margin, South China Sea and its implication

    NASA Astrophysics Data System (ADS)

    Yan, Pin; Wang, Yanlin

    2015-04-01

    The Pearl River Mouth Basin (PRMB) is dominated by NE-trending rift architecture produced mainly during Cenozoic Era. It comprises a series of grabens built up with thick Paleogene and thick Neogene sediments, up to 12000 m, and dividing basement highs composing Yanshanian granitic rocks. Though previously considered as one constituent part of PRMB in the southeast, Dongsha Basin displays major differences in sedimentary architecture and tectonic framework. Firstly, Dongsha Basin is characterized by a prominent angular unconformity, interpreted as a spectacular planation or rough erosion surface which separates the sediment column into two distinct parts. It is interpreted with accumulating seismic and drill data that the underlying strata comprise Early Cretaceous terrestrial, Jurassic marine and possibly Triassic sedimentary rocks totaling to 4~9 km thick, whereas the overlying strata are very thin (usually 0.5~1 km in whole) composing mainly Neogene sediments. The major sedimentary hiatus between them corresponds to the Late Cretaceous to mid-Miocene Epoch, well during the rifting to spreading process when the PRMB developed. Secondly, unlike the PRMB, the Dongsha Basin has suffered considerably less extension except its boundary areas, and actually remained as a relatively stable block though Cenozoic Era. Moreover, there are a few compressive open fold structures within the buried Mesozoic strata over the central Dongsha Basin. These folds trend in NNE and are characterized mostly by few minor growing upthrust faults with offsets in the order of few tens to hundreds meter. The upthrust faults dipped mostly southeastward against the northwestward subduction of paleo-Pacific plate as postulated in other previous study. The blind folds featured more like back-thrust growth tectonics, formed a broad NNE-SSW trending belt, obviously oblique to the trend of northern margin of the South China Sea and the PRMB as well. In a few recent models, the most prominent

  15. Detrital provenance of Early Mesozoic basins in the Jiangnan domain, South China: Paleogeographic and geodynamic implications

    NASA Astrophysics Data System (ADS)

    Xu, Xianbing; Tang, Shuai; Lin, Shoufa

    2016-04-01

    Detrital provenance analysis is an effective way to understand paleogeographic change and geodynamics. In this paper, we present petrological, whole-rock geochemical and detrital zircon U-Pb geochronological analysis of Early and Middle Jurassic terrestrial clastic rocks in the Jingdezhen Basin and the Huangshan Basin in the Jiangnan domain, South China. Petrology and whole-rock geochemistry show that the source rocks are dominated by intermediate to acid component. The Chemical Index of Alteration ranges from 69 to 86, suggesting a moderate weathering history for the source rocks. The Early-Middle Jurassic sediments in the Jingdezhen and Huangshan basins were mostly sourced from magmatogenic greywackes and felsic magmatic rocks, respectively. Detrital zircons have seven age peaks at ~ 240 Ma, ~ 430 Ma, ~ 1390 Ma, ~ 1880 Ma, ~ 2500 Ma, -3200 Ma and 788-999 Ma (a wide peak). Provenance analysis indicates that the source rocks are in the Jiangnan domain, the Northwest Zhejiang Basin and the Wuyishan domain. Combining these with previous results and paleocurrent directions, we infer that the NE-trending Wuyishan and Xuefengshan domains and the nearly E-W-Jiangnan domain and Nanling tectonic belt were orogenic uplifts and watersheds during the Late Triassic to Middle Jurassic. The Early Mesozoic geodynamics in the South China Block was related to the westward subduction of the Paleo-Pacific Plate and the northward continent-continent collision following the closure of the Paleo-Tethys Ocean.

  16. Hydropower Ambitions of South Asian Nations: Ganges and Brahmaputra River basins

    NASA Astrophysics Data System (ADS)

    Mizanur Rahaman, Muhammad

    2010-05-01

    This paper analyses the current status of hydropower development in two major river basins in South Asia, the Ganges and the Brahmaputra. The total drainage area of the basins is about 1660,000 km2 shared by China, Nepal, India, Bhutan, and Bangladesh. The basins are blessed with ample water resources and huge hydropower potential. Hydropower development is strongly linked with the overall development framework of the region. The abundant hydropower potential of the Ganges and the Brahmaputra can help give riparian countries a safer energy future that is the key driving force behind the prospect of potential cooperation in the field of water. Based on four years research studies (2005-2009), this paper analyse the hydropower development plans and ambitions of riparian nations with special focus on China and India. The finding suggests that it is essential to develop an integrated hydropower development approach involving all riparian nations intended to foster regional development and overcome the prospect of severe conflict because of unilateral hydropower ambitions of China and India. The hydropower development cooperation between China and India could also become the positive turning point in the integration of South and South-East Asia.

  17. Volume of Impact Melt Generated by the Formation of the South Pole-Aitken Basin

    NASA Technical Reports Server (NTRS)

    Petro, Noah E.

    2011-01-01

    The South Pole-Aitken Basin (SPA) is the largest, deepest, and oldest identified basin on the Moon and as such contains surfaces that are unique due to their age, composition, and depth of origin in the lunar crust [1-5] (Figure 1). SPA has been a target of intense interest as an area for robotic sample return in order to determine the age of the basin and the composition and origin of its interior [6-8]. In response to this interest there have been several efforts to estimate the likely provenance of regolith material within central SPA [9-12]. These model estimates suggest that, despite the formation of basins and craters following SPA, the regolith within SPA is dominated by locally derived material. An assumption of these models has been that the locally derived material is primarily SPA impact-melt as opposed to local basement material (e.g. unmelted lower crust). However, the definitive identification of SPA derived impact melt on the basin floor, either by remote sensing [5, 13] or via photogeology [2, 14] is extremely difficult due to the number of subsequent impacts and volcanic activity [4].

  18. Benthic infaunal communities across the Weddell Sea Basin and South Sandwich Slope, Antarctica

    NASA Astrophysics Data System (ADS)

    Blake, James A.; Narayanaswamy, Bhavani E.

    2004-07-01

    The present study represents the first quantitative investigation of deep-sea benthic infauna in Antarctica. Box cores and multicores were used to collect sediment from 12 stations across the slope and abyssal basin of the Weddell Sea and the slope off the South Sandwich Islands, including sites in the South Sandwich Trench (6300 m). The multicore was a more efficient sampler than the box core. Nine phyla of invertebrates were found, dominated by annelids (67%), crustaceans (20%); other phyla (13%). A total of 117 taxa were identified to the species level: 72 were polychaetes; 45 were crustaceans. Many taxa are new to science. Highest densities were at the 1000 m depth on the western slope of the Weddell Sea (260 individuals per 0.1 m -2) and at ca. 2200 m on the South Sandwich Slope (132 individuals per 0.1 m -2); lowest densities were in the central Weddell Sea Basin (39 individuals per 0.1 m -2). Species richness and rarefaction analysis suggest that the fauna is undersampled. The 117 species identified in this study were represented by only 237 specimens, indicating that species were being added at a rate of one species for every two specimens collected. Rarefaction curves do not begin to reach an asymptote supporting high estimates of diversity. Some species appear to be limited to distinct zones in upper and middle slope depths, other species extend from the slope to the abyssal basin, and at least two species appear to be restricted to the abyssal basin. In general, the densities of infauna on the slopes surrounding the Weddell Sea Basin have lower densities than well-studied areas off North America. However, abyssal populations in Antarctica appear to have denser infaunal populations than those from off New England and the North Pacific Gyre. Productive surface waters of the Weddell Sea and subsequent sinking of phytoplankton to the seabed are probable reasons for the higher benthic productivity in Antarctic abyssal sediments. Similarity analyses were not

  19. Coastal dynamics of Garabogazköl bay of Caspian Sea

    NASA Astrophysics Data System (ADS)

    Kurbanov, Redzhep

    2016-04-01

    Garabogazköl is extremely interesting object for the study of coastal evolution and Caspian sea paleogeography. Bay plays an important role in evolution of the Caspian basin, as a major area of permanent loss of sea water, the volume of which varies in different years from 17 to 23 km3/year, averaging about 20.3 km3/year. Termination of runoff into the bay would provide annual Caspian Sea level rise of about 3 cm. Despite the large-scale research of the coast of the Caspian Sea during the Soviet era, Garabogazköl was generally poorly studied, mostly describing sedimentation patterns of salt deposits (associated with the production of sulfates). The basis of our study was the materials of remote sensing (satellite imagery), supported by field research, description of geomorphological structure of coasts. As known, the Caspian Sea level was at the lowest elevations from 1970 to 1985, ranging from -28.6 to -29.01 m. The creation of the dam in 1980 completely blocked Caspian water inflow into the Gulf, resulting even more drastic reduction in its area, which decreased by 3 times (from 18 to 6 thousand. km2), with depth less than 50 cm. In mid-1992, when the level of the Caspian Sea has risen by more than 2 meters over the level of 1978, the dam was destroyed. The obtained data allowed characterizing the peculiarities of the coast of the Gulf in these conditions. During the start of the coastal retreat first appeared drained relatively shallow northern and western parts. During this period the processes of accumulation were predominate. There was the deposition of thick (up to 1 m) salt horizon. Dominating wind-surge processes resulted relatively smoothed surface, filling rugged topography by terrigenous material and salt. After the explosion of the dam in 1992, the bay was quickly filled with water and in the next 3-4 years is completely covered the Gara-Bogaz depression. In general, a high stability of the coastline of the Gulf observed through analysis of the last

  20. Tectonic Subsidence Analysis of the Pearl River Mouth Basin, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, X.; Huang, S. S. X. E. C.; Zhuang, W.; LIU, Z.; Duan, W.; Hu, S.

    2015-12-01

    The Pearl River Mouth Basin (PRMB hereafter) in the northern margin of the South China Sea has attracted great attention not only because of its special tectonic location but also for its abundant hydrocarbon resources. Tectonic evolution controls the petroleum geological condition of hydrocarbon-bearing basins. Efforts have been made to understand the tectonic evolution of this basin. However, many issues about the tectonic features and the evolution process of this basin, such as the age of the breakup unconformities and the anomalously accelerated subsidence during the post-rifting stage, remain controversial. Here we employ tectonic subsidence analysis of sedimentary basins, a technique of removing isostatic loading and compaction effects by back-stripping, to investigate the tectonic controls on the basin formation of the PRMB. We performed the analysis on 4 drill wells and 43 synthetic wells constructed based on recently acquired seismic profiles. The result shows that tectonic subsidence in the eastern sags of the PRMB began to decrease at ~30Ma while in the western sags the onset was ~23.8Ma. This suggests that the break-up time i.e. the end of rifting in the PRMB is earlier in the eastern sags than in the western sags. Abnormally accelerated tectonic subsidence occurred between 17.5-16.4Ma during the post-rifting stage, at an average subsidence rate as high as 301.9m/Ma. This phenomenon discriminates the PRMB from the category of classical Atlantic passive continental marginal basins, of which the tectonic subsidence during the post-rifting stage decays exponentially. The main objective of this paper is to provide insights into the geological and geodynamic evolution of the PRMB. The result bears significance to hydrocarbon exploration in this region.

  1. Ground-water quality in alluvial basins that have minimal urban development, south-central Arizona

    USGS Publications Warehouse

    Gellenbeck, Dorinda J.; Coes, Alissa L.

    1999-01-01

    Ground-water quality data (1917-96) from 772 wells in 16 alluvial basins that have minimal urban development were used to determine the effect of nonurban factors on ground-water quality in south- central Arizona. Characterization of the spatial variability of ground-water quality within and among alluvial basins that have minimal urban development will provide a baseline to which water- quality problems associated with urbanization can be compared. Four water-type categories--calcium carbonate, calcium mixed anion, sodium carbonate, and sodium chloride--were used to classify the 13 alluvial basins for which adequate data were available. Ground-water quality was compared to U.S. Environmental Protaection Agency maximum contaminant levels for drinking water, depth of well, and depth to top of perforated interval for five alluvial basins that represented the four water-type categories. Exceedances of maximum contaminant levels for fluoride and nitrate occurred in three and four basins, respectively, of the five selected basins. Specific-conductance values for ground water in the five selected basins tend to increase in a northwesterly direction toward the central part of Arizona as the extent of evaporite deposits increases. The results of this study, which are part of the U.S. Geological Survey's National Water-Quality Assessment Program, can be used to determine the effects of urban land-use activities on ground-water quality in similar hydrogeologic conditions and may be the best indicator available for nonurban ground-water quality in the region.

  2. Nutrient concentrations in wastewater treatment plant effluents, South Platte River Basin

    USGS Publications Warehouse

    Pocernich, M.; Litke, D.W.

    1997-01-01

    Accurate data about nutrient concentrations in wastewater treatment plant effluents are needed for river basin water-quality studies. As part of the U.S. Geological Survey's National Water-Quality Assessment Program in the South Platte River Basin, nutrient data were requested from 31 wastewater-treatment plants located in the basin. This article describes the types of nutrient data available from the plants, examines the variability of effluent nutrient concentrations, and discusses methods for estimation of nutrient concentrations where data are lacking. Ammonia was monitored at 88 percent of the plants, nitrite plus nitrate was monitored at 40 percent of the plants, and organic nitrogen and phosphorus were monitored at less than 25 percent of the plants. Median total nitrogen concentrations and median total phosphorus concentrations were small compared to typical literature estimates for wastewater-treatment plants with secondary treatment. Nutrient concentrations in effluent from wastewater-treatment plants varied widely between and within plants. For example, ammonia concentrations varied as much as 5 mg/L during a day, as much as 10 mg/L from day to day, and as much as 30 mg/L from summer to winter within a plant. In the South Platte River Basin, estimates of median annual ammonia and nitrite plus nitrate concentrations can be improved based on plant processes; and nitrite plus nitrate and organic nitrogen concentrations can be estimated based on ammonia concentrations. However, to avoid large estimation errors, mere complete nutrient data from wastewater-treatment plants are needed for integration into river basin water quality studies. The paucity of data hinders attempts to evaluate the relative importance of point source and nonpoint source nutrient loadings to rivers.

  3. Seismic attribute analysis to enhance detection of thin gold-bearing reefs: South Deep gold mine, Witwatersrand basin, South Africa

    NASA Astrophysics Data System (ADS)

    Manzi, M. S. D.; Hein, K. A. A.; Durrheim, R.; King, N.

    2013-11-01

    The gold-bearing Upper Elsburg Reef clastic wedge (UER) in the South Deep gold mine in the Witwatersrand basin (South Africa) hosts the highly auriferous basal conglomerate known as the Elsburg Conglomerate (EC) reef. The reef is less than 20 m thick and together with quartzite and conglomerate beds in the UER (1-120 m thick) is below the seismic tuning thickness, or the dominant quarter wavelength. They are extremely difficult to identify on migrated seismic sections using traditional amplitude interpretations. In order to enhance the detection of the EC reef and its subcrop position against the overlying Ventersdorp Contact Reef (VCR), complex-trace seismic attributes, or instantaneous attributes and volume attribute analysis were applied on prestack time migrated (PSTM) seismic sections. In particular, the instantaneous phase and paraphase allowed the clear identification of the continuity of the EC reef, and overlapping and interfering wavelets produced by the convergence of VCR and the EC reef. In addition, these attributes increased confidence in the interpretation of the EC, in particular its offsets (faults), and its depth. A high correlation between the seismically determined depth of the EC reef and borehole intersections was observed, with several depth discrepancies below the vertical seismic resolution limit (~ 25 m). This information can now be incorporated into the current mine geological model, thus improving the resource evaluation of the Upper Elsburg Reef in the South Deep gold mine.

  4. The sound speed in southern deepwater zone of the Caspian Sea, off Anzali Port

    NASA Astrophysics Data System (ADS)

    Jamshidi, S.; Abu Bakar, N. B.

    2011-03-01

    Sound velocity determination in seawater is a key component of modern hydrographic surveying; however, little data exists on sound velocity characteristics of the southern Caspian Sea. Hence, a study was undertaken in 2008 to examine the seasonal variability of sound speed in deep-waters of the South Caspian Sea near the Iranian coast. The seasonal cycle of seawater temperature and thermal stratification in the Caspian Sea water created a wide range of spatial and temporal changes of sound speed with relevant differences between shallow water (over the continental shelf) and deep-water area. The collected data showed that seasonal variations of the sound speed were most important in the upper 100 m water depth, while below this level that is in deepwater the changes were small. The maximum values of sound speed were observed at the surface in midsummer around 1517-1519 m s-1 over the continental shelf while the speed of sound was about 1453 m s-1 between 450-470 m depths with no major seasonal variations. Variations in vertical structure of the sound speed were in agreement with temperature changes, while effects of the salinity on the sound speed were little.

  5. A review of stratigraphy and sedimentary environments of the Karoo Basin of South Africa

    NASA Astrophysics Data System (ADS)

    Smith, R. M. H.

    The Karoo Supergroup covers almost two thirds of the present land surface of southern Africa. Its strata record an almost continuous sequence of continental sedimentation that began in the Permo-Carboniferous (280 Ma) and terminated in the early Jurassic 100 million years later. The glacio-marine to terrestrial sequence accumulated in a variety of tectonically controlled depositories under progressively more arid climatic conditions. Numerous vertebrate fossils are preserved in these rocks, including fish, amphibians, primitive aquatic reptiles, primitive land reptiles, more advanced mammal-like reptiles, dinosaurs and even the earliest mammals. Palaeoenvironmental analysis of the major stratigraphic units of the Karoo sequence demonstrates the effects of more localised tectonic basins in influencing depositional style. These are superimposed on a basinwide trend of progressive aridification attributed to the gradual northward migration of southwestern Gondwanaland out of polar climes and accentuated by the meteoric drying effect of the surrounding land masses. Combined with progressive climatic drying was a gradual shrinking of the basin brought about by the northward migration of the subducting palaeo-Pacific margin to the south. Following deposition of the Cape Supergroup in the pre-Karoo basin there was a period of uplift and erosion. At the same time the southern part of Gondwana migrated over the South Pole resulting in a major ice-sheet over the early Karoo basin and surrounding highlands. Glacial sedimentation in both upland valley and shelf depositories resulted in the basal Karoo Dwyka Formation. After glaciation, an extensive shallow sea remained over the gently subsiding shelf fed by large volumes of meltwater. Black clays and muds accumulated under relatively cool climatic conditions (Lower Ecca) with perhaps a warmer "interglacial" during which the distinctive Mesosaurus-bearing, carbonaceous shales of the Whitehill Formation were deposited

  6. Techniques for estimating the magnitude and frequency of floods in rural basins of South Carolina, 1999

    USGS Publications Warehouse

    Feaster, Toby D.; Tasker, Gary D.

    2002-01-01

    Data from 167 streamflow-gaging stations in or near South Carolina with 10 or more years of record through September 30, 1999, were used to develop two methods for estimating the magnitude and frequency of floods in South Carolina for rural ungaged basins that are not significantly affected by regulation. Flood frequency estimates for 54 gaged sites in South Carolina were computed by fitting the water-year peak flows for each site to a log-Pearson Type III distribution. As part of the computation of flood-frequency estimates for gaged sites, new values for generalized skew coefficients were developed. Flood-frequency analyses also were made for gaging stations that drain basins from more than one physiographic province. The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, updated these data from previous flood-frequency reports to aid officials who are active in floodplain management as well as those who design bridges, culverts, and levees, or other structures near streams where flooding is likely to occur. Regional regression analysis, using generalized least squares regression, was used to develop a set of predictive equations that can be used to estimate the 2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence-interval flows for rural ungaged basins in the Blue Ridge, Piedmont, upper Coastal Plain, and lower Coastal Plain physiographic provinces of South Carolina. The predictive equations are all functions of drainage area. Average errors of prediction for these regression equations ranged from -16 to 19 percent for the 2-year recurrence-interval flow in the upper Coastal Plain to -34 to 52 percent for the 500-year recurrence interval flow in the lower Coastal Plain. A region-of-influence method also was developed that interactively estimates recurrence- interval flows for rural ungaged basins in the Blue Ridge of South Carolina. The region-of-influence method uses regression techniques to develop a unique

  7. Assessment of unconvential (tight) gas resources in Upper Cook Inlet Basin, South-central Alaska

    USGS Publications Warehouse

    Schenk, Christopher J.; Nelson, Philip H.; Klett, Timothy R.; Le, Phuong A.; Anderson, Christopher P.; Schenk, Christopher J.

    2015-01-01

    A geologic model was developed for the assessment of potential Mesozoic tight-gas resources in the deep, central part of upper Cook Inlet Basin, south-central Alaska. The basic premise of the geologic model is that organic-bearing marine shales of the Middle Jurassic Tuxedni Group achieved adequate thermal maturity for oil and gas generation in the central part of the basin largely due to several kilometers of Paleogene and Neogene burial. In this model, hydrocarbons generated in Tuxedni source rocks resulted in overpressure, causing fracturing and local migration of oil and possibly gas into low-permeability sandstone and siltstone reservoirs in the Jurassic Tuxedni Group and Chinitna and Naknek Formations. Oil that was generated either remained in the source rock and subsequently was cracked to gas which then migrated into low-permeability reservoirs, or oil initially migrated into adjacent low-permeability reservoirs, where it subsequently cracked to gas as adequate thermal maturation was reached in the central part of the basin. Geologic uncertainty exists on the (1) presence of adequate marine source rocks, (2) degree and timing of thermal maturation, generation, and expulsion, (3) migration of hydrocarbons into low-permeability reservoirs, and (4) preservation of this petroleum system. Given these uncertainties and using known U.S. tight gas reservoirs as geologic and production analogs, a mean volume of 0.64 trillion cubic feet of gas was assessed in the basin-center tight-gas system that is postulated to exist in Mesozoic rocks of the upper Cook Inlet Basin. This assessment of Mesozoic basin-center tight gas does not include potential gas accumulations in Cenozoic low-permeability reservoirs.

  8. Late Permian to Late Triassic basin evolution of North Vietnam: geodynamic implications for the South China and Indochina blocks

    NASA Astrophysics Data System (ADS)

    Rossignol, Camille; Bourquin, Sylvie; Hallot, Erwan; Poujol, Marc; Roger, Françoise

    2015-04-01

    The core of South East Asia is composed of a mosaic of continental blocks, among which the Indochina and the South China blocks (present day northern Vietnam), amalgamated during the Permian and/or the Triassic. Late Permian to Late Triassic geodynamic evolution of these two blocks remains controversial. The main discussion points concern the existence and the closure of an oceanic domain separating the Indochina and the South China blocks during this period. Especially, the polarity and the timing of the subduction zone that led to the collision between the blocks as well as the present location of the suture delimiting them are a matter of debate. Despite the valuable information they can provide, the sedimentary basins from northern Vietnam have been neglected in the previous studies dealing with the geodynamic evolution of South East Asia. To determine the geodynamic evolution of the area, the basins of Sam Nua and Song Da, presently located in North Vietnam, have been investigated using a combined approach involving sedimentology, geochronology (U-Pb/zircon) and geochemistry (whole-rock major and trace elements composition of both volcanic and volcaniclastic rocks). The palaeoenvironment evolution, the main unconformities, their age and the tectonic affinities of the interbedded volcanic and volcaniclastics series have been characterized for these two basins. Our results demonstrate (i) that the Song Da Basin exhibits a palaeogeographic affinity with the South China block, (ii) the occurrence of extensive calk-alkaline volcanism and associated volcaniclastic deposits in the Sam Nua Basin, related to the existence of an active magmatic arc during the Early and the lower Middle Triassic, (iii) a South dipping (present day coordinate) oceanic lithosphere beneath the Indochina block, deduced from the location of the magmatic arc south of the potential suture zones, (iv) that an angular unconformity postdates the lower Middle Triassic volcaniclastic deposits in the

  9. Thermal springs in the Boise River basin, south-central Idaho

    USGS Publications Warehouse

    Lewis, R.E.; Young, H.W.

    1982-01-01

    The Boise River Basin, characterized by steep, rugged mountains and narrow river valleys, drains an area of about 2,680 square miles in south-central Idaho. Granitic rocks of the Idaho batholith predominate in the basin. Temperature of waters from thermal springs in the basin range from 33 degrees to 87 degrees Celsius, are sodium carbonate type and are slightly alkaline. Dissolved-solids concentrations are less than 280 milligrams per liter. Estimated reservoir temperatures determined by the silica and sodium-potassium-calcium geothermometers range from 50 degrees to 98 degrees Celsius. Tritium concentrations in sampled thermal springs are near zero and indicate these waters were recharged prior to 1954. Stable-isotope data are not conclusive insofar as indicating a source area of recharge for the thermal springs in the basin. Thermal springs discharged at least 4,900 acre-feet of water in 1981, and the associated convective heat flux is 11,000,000 calories per second. (USGS)

  10. Morrowan sedimentation in the Orogrande basin, west Texas and south-central New Mexico

    SciTech Connect

    Connolly, W.M.; Stanton, R.J. Jr.

    1986-03-01

    Morrowan strata in the Hueco and Franklin Mountains reflect deposition within a shallow, gradually subsiding, carbonate shelf lagoon. Postulated environments fluctuated between open shelf lagoon with localized shoaling, restricted inner shelf lagoon, and peritidal settings. Variations in depth were slight, probably not exceeding several tens of meters within the photic zone. The La Tuna Formation (Franklin Mountains) was deposited near the axis (center) of the Orogrande basin; the lower division of the Magdalena limestone (Hueco Mountains), 30 mi east, was deposited 20-30 mi west of the paleoshoreline. Physiographically, the Orogrande sea was a small gulf, offering a certain degree of protection from the Morrowan seaway to the south. Sedimentologically, it was a wide expanse of predominantly quiet-water carbonate sedimentation with subordinate argillaceous influex and coarser peripheral clastics. The Orogrande basin, a stratigraphic feature, corresponds to a blanket deposit of shallow epeiric carbonates. Climatic and orographic effects are invoked to explain the contrasting style of clastic sedimentation in the Delaware and orogrande basins, east and west of the Pedernal uplift. Analysis of Morrowan carbonates reveals no evidence of cyclicity, major transgressions or regressions, or local tectonic activity. Deposition was stable and in equilibrium with a gradually subsiding shallow basin. Based on lithologic, faunal, biostratigraphic, and paleogeographic criteria, the lower division is both laterally and temporally equivalent with the La Tuna Formation. Accordingly, the latter term is advocated in favor of the former, which lacks both priority and formal status.

  11. Application of sequence stratigraphy to oil and gas exploration in Bredasdorp basin offshore South Africa

    SciTech Connect

    Van Wyk, N.J.S.

    1989-03-01

    For more than two decades, oil and gas exploration in offshore South African rift basins within structural synrift plays yielded limited success. After the first oil discovery in postrift sediments in the Bredasdorp basin in 1987, sequence-stratigraphic concepts were applied to the Lower Cretaceous postrift sequences to permit correlation of depositional systems tracts and related facies throughout the basin. Extensive high-resolution seismic coverage and borehole control supported the study. The interplay of diminishing rift tectonics, thermal cooling, and inferred eustatic variations in global sea level produced a distinctive series of repetitive cycle depositional sequences. As many as 10 cyclic sequences and megasequences, deposited between the mid-Valanginian and lower Santonian, can be recognized within resolution limits of regional seismic profiles. Various elements of lowstand systems tracts within these sequences appear to contain potential reservoirs. Highly erosional (type 1) unconformities, commonly exhibiting incised valleys and canyons, provide surfaces on which (1) mounded and sheetlike submarine/basin-floor fans, (2) submarine channel fill and associated mounds and fans, and (3) prograding deltaic/coastal lowstand wedges were deposited. These fans, channel fills, and wedges are top sealed and sourced by transgressive shales and marine condensed sections, deposited at a time of regional transgression of the shoreline. One discovery well and various reservoir-quality sandstones occurring at predicted stratigraphic levels in other wells support the application of the sequence-stratigraphic concepts to hydrocarbon exploration.

  12. Reconstruction of Caspian sea-level fluctuations: Radiocarbon dating coastal and bottom deposits

    SciTech Connect

    Karpytchev, Yu.A. )

    1993-01-01

    Owing to the large basin area of the Caspian Sea, fluctuations in its level reflect climatic changes in the northern hemisphere. To reconstruct these fluctuations, they collected mollusk shells, plant debris, carbonates and organic matter samples for [sup 14]C dating from deposits of ancient salt marshes, depressions and bars formed during significant sea-level decline they studied the impact of eolian sedimentation via parallel dating of carbonates and other materials. The data demonstrate that sea level rises during periods of cooling and falls during warming periods; this is true for both long-term (2--2.5 ka) and short-term climatic changes.

  13. Eddy-entrained Pearl River plume into the oligotrophic basin of the South China Sea

    NASA Astrophysics Data System (ADS)

    He, Xianqiang; Xu, Dongfeng; Bai, Yan; Pan, Delu; Chen, Chen-Tung Arthur; Chen, Xiaoyan; Gong, Fang

    2016-08-01

    The South China Sea (SCS) is the world's largest tropical marginal sea with an oligotrophic basin. In June 2015, a rare large phytoplankton bloom, which is ~500 km long, 100 km wide and lasting more than 19 days, was captured in the northern SCS basin by satellite daily chlorophyll images. Water within the bloom area had a feature of low salinity and high temperature measured by an accidental-passing cruise. Meanwhile, satellite sea level anomaly images and drifter trajectory proved there was a cyclonic eddy nearby. No typhoon and heavy rain happened in this period, so we believed the bloom was triggered by the injection of nutrient-rich Pearl River plume driven by eddy. This is the first report on eddy-entrained Pearl River plume into the SCS, which would raise a new view on irregular transportation of nutrient and carbon and its related biogeochemical influence on the oligotrophic ocean.

  14. Distortion and broadening of internal solitary wavefront in the northeastern South China Sea deep basin

    NASA Astrophysics Data System (ADS)

    Xie, Jieshuo; He, Yinghui; Lü, Haibin; Chen, Zhiwu; Xu, Jiexin; Cai, Shuqun

    2016-07-01

    Internal solitary waves (ISWs) with peculiar fronts are frequently observed in the world ocean by satellite images, though with quite few explanations. In this study a distorted and broadening ISW front across the northeastern South China Sea deep basin is presented by using synthetic aperture radar (SAR) image. To illustrate this peculiar front, a nonlinear refraction model is developed to simulate and evaluate the effects of realistic bottom topography, current, and stratification on its transformation. Simulated results in realistic oceanic environments show good agreements with this SAR-observed front. Based on separate and comparative results in different background environments, we demonstrate that the distortion is actually caused by the strong mesoscale currents at periphery of an anticyclonic eddy. Moreover, the broadening is due to the difference in change of wave half width at different rays, which is associated with the different transformation of ISWs across variable bottom topography in the deep basin.

  15. Redistribution and growth of the Caspian Tern population in the Pacific Coast region of north America, 1981-2000

    USGS Publications Warehouse

    Suryan, R.M.; Craig, D.P.; Roby, D.D.; Chelgren, N.D.; Collis, K.; Shuford, W.D.; Lyons, Donald E.

    2004-01-01

    We examined nesting distribution and demography of the Pacific Coast population of Caspian Terns (Sterna caspia) using breeding records and band recoveries spanning two decades since the first population assessment. Since 1980, population size has more than doubled to about 12 900 pairs, yet the proportion of the population nesting at inland (18%) versus coastal sites (82%) has remained constant. Although the breeding range of the Pacific Coast population has expanded northward into Alaska and farther south in Mexico, there was no net latitudinal shift in the distribution of breeding pairs or new colonies. The distribution of breeding birds among areas changed dramatically, however, with 69% of breeding terns now nesting in Oregon (primarily in the Columbia River estuary) versus 4% during the late 1970s. During the past 20 years, there has continued to be a greater proportion of Caspian Terns breeding at anthropogenic sites compared to natural sites. Estimated annual survival rates for hatch-year and after-third-year birds during 1981-1998 were greater than during 1955-1980, consistent with the higher rate of population increase in recent decades. Fecundity required to maintain a stable population (?? = 1) was estimated at 0.32-0.74 fledglings pair-1, depending on band recovery probabilities for sub-adults. Caspian Terns readily moved among breeding sites and rapidly colonized new areas; however, a greater concentration of breeding Caspian Terns among fewer colonies in response to anthropogenic factors is an important conservation concern for this species.

  16. AIR QUALITY IMPACTS OF LIQUEFIED NATURAL GAS IN THE SOUTH COAST AIR BASIN OF CALIFORNIA

    SciTech Connect

    Carerras-Sospedra, Marc; Brouwer, Jack; Dabdub, Donald; Lunden, Melissa; Singer, Brett

    2011-07-01

    The effects of liquefied natural gas (LNG) on pollutant emission inventories and air quality in the South Coast Air Basin of California were evaluated using recent LNG emission measurements by Lawrence Berkeley National Laboratory and the Southern California Gas Company (SoCalGas), and with a state-of-the-art air quality model. Pollutant emissions can be affected by LNG owing to differences in composition and physical properties, including the Wobbe index, a measure of energy delivery rate. This analysis uses LNG distribution scenarios developed by modeling Southern California gas flows, including supplies from the LNG receiving terminal in Baja California, Mexico. Based on these scenarios, the projected penetratino of LNG in the South Coast Air Basin is expected to be limited. In addition, the increased Wobbe index of delivered gas (resulting from mixtures of LNG and conventional gas supplies) is expected to cause increases smaller than 0.05 percent in overall (area-wide) emissions of nitrogen oxides (NOx). BAsed on the photochemical state of the South Coast Air Basin, any increase in NOx is expected to cause an increase in the highest local ozone concentrations, and this is reflected in model results. However, the magnitude of the increase is well below the generally accepted accuracy of the model and would not be discernible with the existing monitoring network. Modeling of hypothetical scenarios indicates that discernible changes to ambient ozone and particulate matter concentrations would occur only at LNG distribution rates that are not achievable with current or planned infrastructure and with Wobbe index vlaues that exceed current gas quality tariffs. Results of these hypothetical scenarios are presented for consideration of any proposed substantial expansion of LNG supply infrastructure in Southern California.

  17. Quantifying climate and pumping contributions to aquifer depletion using a highly parameterised groundwater model: Uley South Basin (South Australia)

    NASA Astrophysics Data System (ADS)

    Knowling, Matthew J.; Werner, Adrian D.; Herckenrath, Daan

    2015-04-01

    The relative contributions of climate and human stresses to aquifer depletion in real-world settings are rarely quantified, particularly where complex patterns of depletion arise from the spatial and temporal variability in aquifer stresses. These impacts can be assessed using calibration-constrained model predictions of disturbed (i.e., subject to human activity) and undisturbed (i.e., natural) conditions. Prior investigations that adopt this approach employ lumped-parameter or one-dimensional models. Here, we extend previous studies by using a highly parameterised, spatially distributed groundwater model to investigate the relative impacts of climate variability and pumping on aquifer depletion. The Uley South Basin (USB), South Australia, where there is conjecture surrounding the cause of declining groundwater levels, serves as a case study. The relative contributions of climate variability and pumping to USB depletion are shown to be highly variable in time and space. Temporal trends reflect variability in rainfall and pumping, as expected. Spatial trends are primarily dependent on the proximity to both the coastal boundary and pumping wells, and to the distribution of recharge and hydraulic properties. Results show that pumping impacts exceed those of climate between 1978 and 2012, and over the majority of the spatial extent of USB. The contribution of pumping to aquifer depletion is shown to be 2.9 and 1.4 times that of climate in terms of the time-averaged and maximum-in-time basin-scale water budget, respectively. Confidence in model predictions is enhanced by the outcomes of a linear predictive uncertainty analysis, which indicates that predictive uncertainty is lower than climatic and pumping impacts. This study demonstrates the application of a relatively simple analysis that can be used in combination with highly parameterised, spatially distributed groundwater models to differentiate causal factors of aquifer depletion.

  18. Magmatism, structure and age of Dove Basin (Antarctica): A key to understanding South Scotia Arc development

    NASA Astrophysics Data System (ADS)

    Galindo-Zaldívar, Jesús; Puga, Encarnación; Bohoyo, Fernando; González, Francisco Javier; Maldonado, Andrés; Martos, Yasmina M.; Pérez, Lara F.; Ruano, Patricia; Schreider, Anatoly A.; Somoza, Luis; Suriñach, Emma; Antonio, Díaz de Federico

    2014-11-01

    Dove Basin is situated in the south-central Scotia Sea, between Pirie and Bruce banks, and was formed during the development of the Scotia Arc. The basin has a roughly sigmoidal shape, with a prominent NNE-SSW elongated ridge located in its central part, the Dove Ridge, which is considered as an extinct spreading axis. A NE-SW elongated tectonic high, the Dove Seamount, is located in the north-eastern region of the basin, bounded by a normal fault dipping to the southeast. Dredged rocks and geophysical data were collected during the SCAN2004 and SCAN2008 cruises. Dredged samples were recovered from three positive features in the center of the basin, two from Dove Ridge, and one from Dove Seamount. Igneous rocks along the Dove Ridge are mainly tholeiitic basalts, derived from asthenospheric upper mantle within an extensional supra-subduction back-arc tectonic setting, which evolved over time from back-arc basin basalts (BABB) toward Mid Oceanic Ridge Basalts (MORBs). Altered olivine-bearing fine- and medium-grained basaltic rocks were also dredged from Dove Ridge and the seamount, together with minor oceanic island arc basalts and basaltic andesites. The mantle source was affected, up to early Miocene times, by a subducted oceanic slab related to an arc to the east, with Dove Basin forming in a back-arc position. Minor alkaline oceanic island basalts dredged at the seamount might represent a final extensional stage, genetically related with the dying Dove Ridge volcanism or, less probably, to a later, late Miocene-Pliocene extensional stage, producing incipient volcanism deriving from a deeper mantle source. 40Ar/39Ar dating of MORB samples dredged from the Dove Ridge provided ages of 20.4 ± 2.6 to 22.8 ± 3.1 Ma. These outcrops were later coated by Fe-Mn crusts with Co-Chronometer ages ranging from at least 12.6 Ma and probably up to 18 Ma. Analysis of magnetic anomaly profiles shows the best fit in the central profile, corresponding to chrons C6B (21.7 Ma) to C7

  19. Physical characteristics of stream subbasins in the lower Minnesota River basin, south-central Minnesota

    USGS Publications Warehouse

    Sanocki, C.A.

    1997-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Lower Minnesota River Basin, located in south-central Minnesota are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  20. Status and understanding of groundwater quality in the South Coast Interior groundwater basins, 2008: California GAMA Priority Basin Project

    USGS Publications Warehouse

    Parsons, Mary C.; Kulongoski, Justin T.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the approximately 653-square-mile (1,691-square-kilometer) South Coast Interior Basins (SCI) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The South Coast Interior Basins study unit contains eight priority groundwater basins grouped into three study areas, Livermore, Gilroy, and Cuyama, in the Southern Coast Ranges hydrogeologic province. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA South Coast Interior Basins study was designed to provide a spatially unbiased assessment of untreated (raw) groundwater quality within the primary aquifer system, as well as a statistically consistent basis for comparing water quality between basins. The assessment was based on water-quality and ancillary data collected by the USGS from 50 wells in 2008 and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined by the depth intervals of the wells listed in the CDPH database for the SCI study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as trace elements and minor ions. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifer system of the SCI study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration

  1. Status and understanding of groundwater quality in the South Coast Interior groundwater basins, 2008: California GAMA Priority Basin Project

    USGS Publications Warehouse

    Parsons, Mary C.; Kulongoski, Justin T.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the approximately 653-square-mile (1,691-square-kilometer) South Coast Interior Basins (SCI) study unit was investigated as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The South Coast Interior Basins study unit contains eight priority groundwater basins grouped into three study areas, Livermore, Gilroy, and Cuyama, in the Southern Coast Ranges hydrogeologic province. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The GAMA South Coast Interior Basins study was designed to provide a spatially unbiased assessment of untreated (raw) groundwater quality within the primary aquifer system, as well as a statistically consistent basis for comparing water quality between basins. The assessment was based on water-quality and ancillary data collected by the USGS from 50 wells in 2008 and on water-quality data from the California Department of Public Health (CDPH) database. The primary aquifer system was defined by the depth intervals of the wells listed in the CDPH database for the SCI study unit. The quality of groundwater in the primary aquifer system may be different from that in the shallower or deeper water-bearing zones; shallow groundwater may be more vulnerable to surficial contamination. The first component of this study, the status of the current quality of the groundwater resource, was assessed by using data from samples analyzed for volatile organic compounds (VOCs), pesticides, and naturally occurring inorganic constituents, such as trace elements and minor ions. This status assessment is intended to characterize the quality of groundwater resources within the primary aquifer system of the SCI study unit, not the treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentration

  2. Caspian games: A dynamic bargaining game

    NASA Astrophysics Data System (ADS)

    Michaud, Dennis Wright

    This Dissertation was written under the direction of Professor P.Terrence Hopmann. In this work, the author seeks to identify the independent variables affecting the outcome of three key decisions required of the international consortiums constructing Caspian oil export pipelines. The first of involves whether or not the enterprises developing the pipelines to export Kazakh oil, the Caspian Pipeline Consortium ("CPC"), and Azeri oil, the Azerbaijan International Operating Consortium ("CPC"), cooperate by utilizing the same route or utilize separate energy export corridors. Second, I analyzed how the actual Main Export Pipeline route ("MEP") for Azeri oil was selected by the AIOC. Finally, I tried to understand the factors driving the residual equity positions in each consortium. I was particularly interested in the equity position of Russian state and commercial interests in each consortium. I approached the puzzle as a multilevel bargaining problem. Hence, the preferences of each relevant actor (state and corporate levels) were assessed. The covering theory utilized was rational choice. An application of game theoretic modeling, particularly Bayesian analysis (used as a metaphor), accounted for the learning process resulting from the strategic interaction between actors. I sought to understand greater the refinement of each actor's perception of counterpart preferences. Additionally, the Gordon Constant Growth Model ("CGM") and the Sharp's Capital Asset Pricing Model ("CAPM") were utilized to relate multinational actors preferences, achieving a cost of capital based hurdle rate, to political risk. My end findings demonstrate this interrelationship and provide a clear argument for great power states to persuade newly developing Caspian states to adopt a more transparent, and credible approach to corporate governance. This revised state strategy will reduce multinationals' perception of political risk, lower firms' cost of capital (hurdle rate), and increase the

  3. What happens to nutrients in offstream reservoirs in the lower South Platte River basin?

    USGS Publications Warehouse

    Sprague, Lori A.; Kimbrough, Robert A.; Ranalli, Anthony J.

    2002-01-01

    The practice of storing South Platte River water in offstream reservoirs reduces nutrient concentrations but also contributes to the growth of algae, which may adversely affect the recreational use of the reservoirs. Results of a study of five offstream reservoirs in the lower South Platte River Basin during the 1995 irrigation season showed that the reservoirs trapped 20 to 88 percent of incoming nitrogen and phosphorus, except for phosphorus in one reservoir. Total nitrogen concentrations in the reservoirs were highest in March and decreased through September, largely as a result of uptake by algae and other aquatic life for growth. Total phosphorus concentrations in the reservoirs were more variable because of the recycling of phosphorus by aquatic life. Chlorophyll-a concentrations indicated that the amount of algae in all reservoirs increased during the summer and that all reservoirs were eutrophic. This study was done by the U.S. Geological Survey as part of the National Water-Quality Assessment (NAWQA) Program.

  4. Thin-skinned shortening geometries of the South Fork fault: Bighorn basin, Park County, Wyoming

    SciTech Connect

    Clarey, T.L. )

    1990-01-01

    This paper presents a new interpretation of the South Fork fault in light of thin-skinned thrust theory. Cross sections and seismic data are presented which indicate that the South Fork fault is an allochthonous salient which was emplaced in the Bighorn basin during the early to middle Eocene. All observed structural geometries can be interpreted as developing under a compressional regime, similar to the Wyoming-Utah-Idaho thrust belt. Faults either follow bedding-plane surfaces, cut up section in the direction of tectonic transport or form backthrusts. A single decollement within the Jurassic Gypsum Spring Formation appears to dominate. Tectonic transport was approximately southeast, parallel to tear faults in the allochthonous plate.

  5. Effects of landcover, water redistribution, and temperature on ecosystem processes in the South Plate Basin

    USGS Publications Warehouse

    Baron, J. S.; Hartman, M.D.; Kittel, T. G. F.; Band, L.E.; Ojima, D. S.; Lammers, R.B.

    1998-01-01

    Over one-third of the land area in the South Platte Basin of Colorado, Nebraska, and Wyoming, has been converted to croplands. Irrigated cropland now comprises 8% of the basin, while dry croplands make up 31%. We used the RHESSys model to compare the changes in plant productivity and vegetation-related hydrological processes that occurred as a result of either land cover alteration or directional temperature changes (−2°C, +4°C). Land cover change exerted more control over annual plant productivity and water fluxes for converted grasslands, while the effect of temperature changes on productivity and water fluxes was stronger in the mountain vegetation. Throughout the basin, land cover change increased the annual loss of water to the atmosphere by 114 mm via evaporation and transpiration, an increase of 37%. Both irrigated and nonirrigated grains became active earlier in the year than shortgrass steppe, leading to a seasonal shift in water losses to the atmosphere. Basin-wide photosynthesis increased by 80% due to grain production. In contrast, a 4°C warming scenario caused annual transpiration to increase by only 3% and annual evaporation to increase by 28%, for a total increase of 71 mm. Warming decreased basin-wide photosynthesis by 16%. There is a large elevational range from east to west in the South Platte Basin, which encompasses the western edge of the Great Plains and the eastern front of the Rocky Mountains. This elevational gain is accompanied by great changes in topographic complexity, vegetation type, and climate. Shortgrass steppe and crops found at elevations between 850 and 1800 m give way to coniferous forests and tundra between 1800 and 4000 m. Climate is increasingly dominated by winter snow precipitation with increasing elevation, and the timing of snowmelt influences tundra and forest ecosystem productivity, soil moisture, and downstream discharge. Mean annual precipitation of <500 mm on the plains below 1800 m is far less than potential

  6. Towards a South Asia Land Data Assimilation System: first results for transboundary basins

    NASA Astrophysics Data System (ADS)

    Zaitchik, B. F.; Ghatak, D.; Toll, D. L.; Searby, N. D.; Limaye, A. S.; Peters-Lidard, C. D.; Bajracharya, B.; Shrestha, B. R.; Iceland, C.; Narula, K.; Lee, S.; Mourad, B.; Doorn, B.

    2014-12-01

    South Asia faces a remarkably complex and diverse set of hydrologic stresses, including melting glaciers, variable snowpack, intensively utilized transboundary rivers, rapid groundwater depletion due to irrigation, flood and drought hazard, and rapidly changing land use/cover and climate conditions. The management and prediction challenges posed by these conditions are compounded by the sparseness of in situ monitoring sites, particularly in headwaters regions, and a lack of open sharing of hydrometeorological data across national boundaries. As a result, uncertainties in availability in a situation of rising demands are leading to increasing competing and exploitive use of a limited resource, being experienced at various scales. An open water information system for decision support is an absolute necessity. In order to provide an open and spatially complete water information system for decision support across the region, we are implementing a customized Land Data Assimilation System (LDAS) designed to provide best-available estimates of hydrologic states and fluxes across South Asia, both retrospectively and in near-real time. The LDAS merges advanced land surface models with satellite-derived and in situ observations. In the case of South Asia, multiple satellite-derived hydrological fields are relevant to complete water balance analysis, including precipitation from multiple sources (e.g., TRMM, CHIRPS, GPM), water storage anomalies from GRACE, thermal infrared evapotranspiration estimates, and snowpack characteristics from visible and microwave sensors. Each of these observation types can either be ingested to South Asia LDAS or used as an independent observation for comparison. Here we present the first results of this South Asian Land Data Assimilation System, with a focus on complete water balance analysis for selected river basins in South Asia.

  7. Comparative analysis of the Late Cretaceous to Recent post-breakup basin evolution of the South-American and South-African margin of the southern Atlantic

    NASA Astrophysics Data System (ADS)

    Kukla, Peter; Back, Stefan

    2010-05-01

    Recently, considerable attempts have been made to compare the sedimentary basin evolution and the associated tectonic framework on both sides of the South-Atlantic (e.g. Mohriak et al., 2008, and references therein). Yet there are still unresolved questions. Amongst the most striking observations is that multiple phases of volcanism, uplift and subsidence are recorded after the break-up of the southern South Atlantic margin segment on both sides of the Florianopolis - Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup continental margin successions. However, the tectono-sedimentary and magmatic styles markedly differ from south to north across the volcanic complex. In seismic reflection data, voluminous extrusives are manifested by the occurrence of large wedges of seaward dipping reflector sequences south of the volcanic complex, whilst large volumes of Cretaceous mafic alkaline rocks only occur north of the Florianopolis - Walvis Ridge complex. It can be expected that these differences are of a broad importance for the understanding of both break-up and post-breakup processes. This presentation focuses on a comparison of the post-breakup stratigraphic development of the South American and South African continental margins that both record thick post-rift sedimentary successions. Basins along the southern African margin are much narrower in comparison to their South American counterparts, constituting a pronounced margin asymmetry across the Atlantic. Adding to the heterogeneity of the system, the northernmost segment of the South Atlantic rift and salt basins is also characterized by a pronounced asymmetry, with the Brazilian margin now comprising narrower and deeper rift basins with less salt than the Congo-Gabon conjugate margin. In general, it seems that in the salt-prone areas both offshore South America and southern Africa, salt-related tectonics are amongst the key parameters

  8. Moonrise: Sampling the South Pole-Aitken Basin to Address Problems of Solar System Significance

    NASA Technical Reports Server (NTRS)

    Zeigler, R. A.; Jolliff, B. L.; Korotev, R. L.; Shearer, C. K.

    2016-01-01

    A mission to land in the giant South Pole-Aitken (SPA) Basin on the Moon's southern farside and return a sample to Earth for analysis is a high priority for Solar System Science. Such a sample would be used to determine the age of the SPA impact; the chronology of the basin, including the ages of basins and large impacts within SPA, with implications for early Solar System dynamics and the magmatic history of the Moon; the age and composition of volcanic rocks within SPA; the origin of the thorium signature of SPA with implications for the origin of exposed materials and thermal evolution of the Moon; and possibly the magnetization that forms a strong anomaly especially evident in the northern parts of the SPA basin. It is well known from studies of the Apollo regolith that rock fragments found in the regolith form a representative collection of many different rock types delivered to the site by the impact process (Fig. 1). Such samples are well documented to contain a broad suite of materials that reflect both the local major rock formations, as well as some exotic materials from far distant sources. Within the SPA basin, modeling of the impact ejection process indicates that regolith would be dominated by SPA substrate, formed at the time of the SPA basin-forming impact and for the most part moved around by subsequent impacts. Consistent with GRAIL data, the SPA impact likely formed a vast melt body tens of km thick that took perhaps several million years to cool, but that nonetheless represents barely an instant in geologic time that should be readily apparent through integrated geochronologic studies involving multiple chronometers. It is anticipated that a statistically significant number of age determinations would yield not only the age of SPA but also the age of several prominent nearby basins and large craters within SPA. This chronology would provide a contrast to the Imbrium-dominated chronology of the nearside Apollo samples and an independent test of

  9. South Sumatra Basin Province, Indonesia; the Lahat/Talang Akar-Cenozoic total petroleum system

    USGS Publications Warehouse

    Bishop, Michele G.

    2000-01-01

    Oil and gas are produced from the onshore South Sumatra Basin Province. The province consists of Tertiary half-graben basins infilled with carbonate and clastic sedimentary rocks unconformably overlying pre-Tertiary metamorphic and igneous rocks. Eocene through lower Oligocene lacustrine shales and Oligocene through lower Miocene lacustrine and deltaic coaly shales are the mature source rocks. Reserves of 4.3 billion barrels of oil equivalent have been discovered in reservoirs that range from pre-Tertiary basement through upper Miocene sandstones and carbonates deposited as synrift strata and as marine shoreline, deltaic-fluvial, and deep-water strata. Carbonate and sandstone reservoirs produce oil and gas primarily from anticlinal traps of Plio-Pleistocene age. Stratigraphic trapping and faulting are important locally. Production is compartmentalized due to numerous intraformational seals. The regional marine shale seal, deposited by a maximum sea level highstand in early middle Miocene time, was faulted during post-depositional folding allowing migration of hydrocarbons to reservoirs above the seal. The province contains the Lahat/Talang Akar-Cenozoic total petroleum system with one assessment unit, South Sumatra.

  10. Groundwater flow in an intermountain basin: Hydrological, geophysical, and geological exploration of South Park, Colorado

    NASA Astrophysics Data System (ADS)

    Ball, Lyndsay Brooke

    Groundwater in the intermountain basins of the American West is increasingly of interest with respect to water supply, ecosystem integrity, and contaminant and heat transport processes. These basins are defined by their heterogeneity through large topographic relief, substantial climatic variability, and permeability distributions made complex through variations in lithology and deformation over the orogenic history of these regions, leading to folded and faulted aquifers. This dissertation focuses on the influence of these heterogeneities on the groundwater flow system of the South Park basin in central Colorado, USA. The influence of faults on shallow groundwater flow was examined at two locations along the mapped trace of the Elkhorn fault, a Laramide reverse fault that juxtaposes crystalline and sedimentary rocks in eastern South Park. At the first location, electromagnetic, resistivity, self-potential, and hydraulic data were collected at an existing well field straddling the fault trace. Integrated analysis suggested the fault behaves as combined conduit barrier to groundwater in flow the upper 60 m. A second location along the mapped trace was selected through additional geophysical exploration. New boreholes were drilled to make direct geologic, hydrologic, and geophysical observations of the fault zone. However, these boreholes did not intersect the Elkhorn fault despite passing through rocks with similar electrical resistivity signatures to the first study location. Analyses of drill core and geophysical data indicate that the mineralogical composition of the crystalline rocks strongly influences their resistivity values, and the resistivity contrasts associated with the rock juxtaposition created by the Elkhorn fault is not unique. A steady-state, three-dimensional groundwater flow model of the South Park basin was developed to explore the influence of complex topography, recharge, and permeability structure on regional groundwater flow. Geologic

  11. Radiogenic heat production in sedimentary rocks of the Gulf of Mexico Basin, south Texas

    USGS Publications Warehouse

    McKenna, T.E.; Sharp, J.M.

    1998-01-01

    Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we calculate radiogenic heat production for Stuart City (Lower Cretaceous) limestones, Wilcox (Eocene) sandstones and mudrocks, and Frio (Oligocene) sandstones and mudrocks from south Texas. Heat production rates range from a low of 0.07 ?? 0.01 ??W/m3 in clean Stuart City limestones to 2.21 ?? 0.24??W/m3 in Frio mudrocks. Mean heat production rates for Wilcox sandstones, Frio sandstones, Wilcox mudrocks, and Frio mudrocks are 0.88, 1.19, 1.50, and 1.72 ??W/m3, respectively. In general, the mudrocks produce about 30-40% more heat than stratigraphically equivalent sandstones. Frio rocks produce about 15% more heat than Wilcox rocks per unit volume of clastic rock (sandstone/mudrock). A one-dimensional heat-conduction model indicates that this radiogenic heat source has a significant effect on subsurface temperatures. If a thermal model were calibrated to observed temperatures by optimizing basal heat-flow density and ignoring sediment heat production, the extrapolated present-day temperature of a deeply buried source rock would be overestimated.Radiogenic heat production within the sedimentary section of the Gulf of Mexico basin is a significant source of heat. Radiogenic heat should be included in thermal models of this basin (and perhaps other sedimentary basins). We calculate that radiogenic heat may contribute up to 26% of the overall surface heat-flow density for an area in south Texas. Based on measurements of the radioactive decay rate of ??-particles, potassium concentration, and bulk density, we

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

    SciTech Connect

    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 regressive 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.

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

    SciTech Connect

    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 regressive 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.

  14. Diagenesis and reservoir quality of Paleocoene sandstones in the Kupe South field, Taranaki Basin, New Zealand

    SciTech Connect

    Martin, K.R. ); Baker, J.C. ); Hamilton, P.J. ); Thrasher, G.P. )

    1994-04-01

    The Kupe South field, Taranaki basin, New Zealand is a gas condensate and oil field offshore in the southern Taranaki basin. Its Paleocene reservoir sandstones contain a diagenetic mineral assemblage that records major shifts in pore-water composition during the burial history of the basin. Early calcite formed a shallow burial largely from meteoric depositional pore waters, whereas later chlorite/smectic records the downward passage of marine pore waters into the sandstones from overlying, marine mudrocks prior to significant sandstone compaction during the late Miocene. Late calcite and ferroan carbonates may record the presence of connate meteoric water expelled upward from nonmarine sedimentary rocks of the underyling Cretaceous sequence, whereas later kaolinite and secondary porosity formation are related to localized meteoric influx resulting from late Miocene to early Pliocene uplift and erosion of the reservoir section. Hydrocarbon entrapment occurred during further Pliocene to Holocene sediment accumulation. Labile-grain alteration has been less severe in the lower part of the hydrocarbon-bearing section than in the upper sands with the result that the lower sands contain mainly chlorite/smectite and the upper sands contain mainly ferroan carbonates and kaolinite formed by extensive alteration of labile grains and earlier formed chlorite/smectite. Reservoir quality in the lower sands is controlled mostly by grain size and the presence of chlorite/smectite, but in the upper sands, the presence of kaolinite is the single most important cause of poor reservoir quality. 36 refs., 13 figs., 3 tabs.

  15. Rapid vertebrate recuperation in the Karoo Basin of South Africa following the End-Permian extinction

    NASA Astrophysics Data System (ADS)

    Botha, J.; Smith, R. M. H.

    2006-08-01

    The mass extinction that occurred at the end of the Permian Period approximately 251 Mya is widely accepted as the most devastating extinction event in Earth's history. An estimated 75-90% of global diversity from both marine and terrestrial realms disappeared synchronously within at most one million and perhaps as little as 100,000 years. To date, most research has focused on the marine record and it is only recently that a few fully preserved terrestrial Permo-Triassic boundary sequences have been discovered. The main Karoo Basin of South Africa hosts several well-preserved non-marine Permo-Triassic boundary sequences that have been the focus of intensive research into the nature of the extinction and its possible causes. This study uses sedimentological and biostratigraphic data from boundary sequences near Bethulie in the southern Karoo Basin to make assumptions about the rates and timing of recovery of the terrestrial fauna in this portion of southern Gondwana after the extinction event. The biostratigraphic data gathered from 277 in situ vertebrate fossils allows us to define more accurately the temporal ranges of several taxa. These data also confirm a more precise extinction rate in this part of the basin of 54% of latest Permian vertebrate taxa, followed by the onset of a relatively rapid recovery, within an estimated 40-50 thousand years (based on the calculation of floodplain aggradation rates and compaction ratios) that included the origination of at least 12 new vertebrate taxa from amongst the survivors.

  16. Mineralogy of the Mafic Anomaly in the South Pole-Aitken Basin: Implications for excavation of the lunar mantle

    NASA Technical Reports Server (NTRS)

    Pieters, C. M.; Tompkins, S.; Head, J. W.; Hess, P. C.

    1997-01-01

    Mineralogy of South Pole-Aitken Basin (SPA) (the largest confirmed impact basin on the Moon) is evaluated using five-color images from Clementine. Although olivine-rich material as well as basalts rich in clinopyroxene are readily identified elsewhere on the farside, the dominant rock type observed across the interior of SPA is of a very noritic composition. This mineralogy suggests that lower crust rather than the mantle is the dominant source of the mafic component at SPA. The lack of variation in observed noritic composition is probably due to basin formation processes, during which extensive melting and mixing of target materials are likely to occur.

  17. Geological and geochemical analysis of stratigraphic units in the South Pole - Aitken Basin

    NASA Astrophysics Data System (ADS)

    Borst, A.; Bexkens, F.; Foing, B.; Koschny, D.; Davies, G.; van Westrenen, W.

    2009-04-01

    The South Pole-Aitken (SPA) Basin, located on the Lunar far side, is one of the oldest and largest recognized impact structure in the solar system. This PreNectarian basin (>3.9 Ga) measures 2500 km in diameter with depths up to 13 km. A large mafic province was formed by the impact that effectively removed the upper crust [1]. Hence, deep-seated lower crustal and possibly even mantle materials are exposed in the severely modified Basin interior, providing the unique opportunity to probe and study the composition and structure of the Lunar interior. Consequently, the SPA Basin is a frequently proposed site for future sample return missions and detailed multispectral studies will required to aid landing site selection [2]. Previous studies on the multispectral dataset of Clementine (1994) by Pieters and Tompkins [1,3] revealed fresh mafic compositions of both low-Ca pyroxene or high-Ca pyroxene dominated rocks, referred to as norites and gabbros respectively. Some regions contained spectral features of olivine (troctolite), such as in Olivine Hill, which could suggest the presence of mantle derived deposits tapped during SPA impact. Using an algorithm developed by Pieters et al. [1] we have produced images for three subregions, covering the central and northern part of the SPA Basin. The algorithm is based on three diagnostic features in the UV/VIS spectrum of Clementine's 11 band multispectral dataset. The parameters are assigned to an RGB composite and allow distinction between mature soils, anorthosite (blue), norite (pink) and gabbro/troctolite compositions (green). Furthermore, we have used Clementine's Near Infrared database to produce a NIR band ratio image (2000 nm/1250 nm), as a parameter to distinguish between olivine and pyroxene-rich materials where we aim to detect traces of excavated mantle material (modified from LeMoeulic et al. [4]). Regretfully, we found that the NIR ratio method does not confirm olivine-rich material exposed in Olivine Hill as it

  18. Mesozoic carbonate-siliciclastic platform to basin systems of a South Tethyan margin (Egypt, East Mediterranean)

    NASA Astrophysics Data System (ADS)

    Tassy, Aurélie; Crouzy, Emmanuel; Gorini, Christian; Rubino, Jean-Loup

    2015-04-01

    The Mesozoïc Egyptian margin is the south margin of a remnant of the Neo-Tethys Ocean, at the African northern plate boundary. East Mediterranean basin developed during the late Triassic-Early Jurassic rifting with a NW-SE opening direction (Frizon de Lamotte et al., 2011). During Mesozoïc, Egypt margin was a transform margin with a NW-SE orientation of transform faults. In the Eastern Mediterranean basin, Mesozoïc margins are characterized by mixed carbonate-siliciclastics platforms where subsidence and eustacy are the main parameters controlling the facies distribution and geometries of the platform-to-basin transition. Geometries and facies on the platform-slope-basin system, today well constrained on the Levant area, where still poorly known on the Egyptian margin. Geometries and stratigraphic architecture of the Egyptian margin are revealed, thanks to a regional seismic and well data-base provided by an industrial-academic group (GRI, Total). The objective is to understand the sismostratigraphic architecture of the platform-slope-basin system in a key area from Western Desert to Nile delta and Levant margin. Mapping of the top Jurassic and top Cretaceous show seismic geomorphology of the margin, with the cartography of the hinge line from Western Desert to Sinaï. During the Jurassic, carbonate platform show a prograding profile and a distally thickening of the external platform, non-abrupt slope profiles, and palaeovalleys incisions. Since the Cretaceous, the aggrading and retrograding mixed carbonate-siliciclastic platform show an alternation of steep NW-SE oblique segments and distally steepened segments. These structures of the platform edge are strongly controlled by the inherited tethyan transform directions. Along the hinge line, embayments are interpreted as megaslides. The basin infilling is characterised by an alternation of chaotic seismic facies and high amplitude reflectors onlaping the paleoslopes. MTC deposits can mobilize thick sedimentary

  19. Imaging the South Pole - Aitken Basin in Backscattered Energetic Neutral Hydrogen Atoms

    NASA Astrophysics Data System (ADS)

    Vorburger, Audrey; Wurz, Peter; Barabash, Stas; Wieser, Martin; Futaana, Yoshifumi; Bhardwaj, Anil; Asamura, Kazushi

    2015-04-01

    The Moon, not being protected by a global magnetic field or an atmosphere, is constantly bombarded by solar wind ions. Until a few years ago, it was tacitly assumed that the impinging solar wind ions are almost completely absorbed ( < 1% reflection) by the lunar surface (e.g. Crider and Vondrak, Adv. Space Res., (2002); Feldman et al., J. Geophys. Res., (2000)). Recent observations by IBEX and the Sub-keV Atom Reflecting Analyzer (SARA) onboard Chandrayaan-1 invalidated this assumption, though: In fact, these measurements showed that the lunar surface very efficiently reflects impinging solar wind ions as energetic neutral atoms (ENAs) (e.g. McComas et al., GRL, 2009; Wieser et al., PSS, 2009). Most recently, a global analysis of lunar hydrogen ENAs measured by SARA showed that on average 16% of the solar wind protons are reflected, and that the reflected fraction can range from less than 8% to more than 24%, depending on location (Vorburger et al., J. Geophys. Res., 2013). Whereas it is established that magnetic anomalies reduce the flux of backscattered hydrogen ENAs by screening-off a fraction of the impinging solar wind ions (e.g. Wieser et al., Planet. Space Sci., (2009); Lue et al., Geophys. Res. Lett., (2011); Vorburger et al., J. Geophys. Res., (2012); Futaana et al., Geophys. Res. Lett., (2013)), the effects of other surface properties such as porosity, roughness, chemical composition, and extent of weathering, was not known. To investigate the effects of these surface properties on the properties of scattered ENAs, we conducted an in-depth analysis of ENA observations near the South Pole - Aitken basin using the complete dataset collected by SARA. The South Pole - Aitken basin is an ideal object for such a study, because it highly differs in many properties from the surrounding terrain. It is very deep (~13 km), possesses strikingly elevated concentrations in iron (~15 wt%) and thorium (~7 wt%), has a low albedo and coincides with a cluster of strong

  20. Volga Delta and the Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Russia's Volga River is the largest river system in Europe, draining over 1.3 million square kilometers of catchment area into the Caspian Sea. The brackish Caspian is Earth's largest landlocked water body, and its isolation from the world's oceans has enabled the preservation of several unique animal and plant species. The Volga provides most of the Caspian's fresh water and nutrients, and also discharges large amounts of sediment and industrial waste into the relatively shallow northern part of the sea. These images of the region were captured by the Multi-angle Imaging SpectroRadiometer on October 5, 2001, during Terra orbit 9567. Each image represents an area of approximately 275 kilometers x 376 kilometers.

    The left-hand image is from MISR's nadir (vertical-viewing) camera, and shows how light is reflected at red, green, and blue wavelengths. The right-hand image is a false color composite of red-band imagery from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras, displayed as red, green, and blue, respectively. Here, color variations indicate how light is reflected at different angles of view. Water appears blue in the right-hand image, for example, because sun glitter makes smooth, wet surfaces look brighter at the forward camera's view angle. The rougher-textured vegetated wetlands near the coast exhibit preferential backscattering, and consequently appear reddish. A small cloud near the center of the delta separates into red, green, and blue components due to geometric parallax associated with its elevation above the surface.

    Other notable features within the images include several linear features located near the Volga Delta shoreline. These long, thin lines are artificially maintained shipping channels, dredged to depths of at least 2 meters. The crescent-shaped Kulaly Island, also known as Seal Island, is visible near the right-hand edge of the images.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory

  1. Cenozoic magmatism in the South China Basin: Decompression melting and implications of an enriched mantle source

    SciTech Connect

    Flower, M.F.J.; Kan Tu; Ming Zhang ); Guanghong Xie )

    1990-06-01

    A widespread eposide of interplate volcanism followed the cessation of seafloor spreading in the South China Basin (SCB), affecting the South China Sea, and fringing areas of southern China and Indochina. Geochemical data for basalts from South China Sea islands and seamounts, Hainan Island, and Taiwan define an enriched (Dupal-like) mantle domain yielding oceanic island basalt (OIB) suites with {Delta}7/4Pb = 2-13, {Delta}8/4Pb = 45-73, {sup 87}Sr/{sup 86}Sr > {approximately}0.70325, Th/Ta > 2, and Th/Ba > 0.02. Opening of the SCB resulted from disaggregation of the South China block in response to the Indo-Eurasian collision, a process involving at least one seafloor spreading episode, terminated by collision of microcontinents with the Philippines and Borneo. The lack of precursive flood basalt suggests that active mantle upwelling was not involved and that melting was a passive effect of lithosphere stretching. However, while mantle decompression at ambient stretching factors ({approximately}1.7-2.5) appears to permit melting on the observed scale, the enriched source may preclude such a simple mantle dynamic. Three alternatives are considered: (1) passive melting of a mature metasomatised boundary layer, (2) active melting of thermally eroded subcontinental lithosphere (deep enrichment) or metasomatised boundary layer (shallow enrichment), and (3) relict diapirs of pre-SCB and/or Java trench subduction slabs (intermediate/deep enrichment). These models are evaluated in terms of chemical and isotopic mass balances associated with the generation and movement of small melt fractions in depleted, nondepleted, and enriched mantle.

  2. Assessment of Undiscovered Oil and Gas Resources of the Williston Basin Province of North Dakota, Montana, and South Dakota, 2008

    USGS Publications Warehouse

    Anna, Lawrence O.; Pollastro, Richard M.; Gaswirth, Stephanie B.; Lewan, Michael D.; Lillis, Paul G.; Roberts, Laura N.R.; Schenk, Christopher J.; Charpentier, Ronald R.; Cook, Troy A.; Klett, Timothy R.

    2008-01-01

    Using a geology-based assessment method, the U.S. Geological Survey estimated mean undiscovered volumes of 3.8 billion barrels of undiscovered oil, 3.7 trillion cubic feet of associated/dissolved natural gas, and 0.2 billion barrels of undiscovered natural gas liquids in the Williston Basin Province, North Dakota, Montana, and South Dakota.

  3. Seismic structure of the crust and uppermost mantle of South America and surrounding oceanic basins

    USGS Publications Warehouse

    Chulick, Gary S.; Detweiler, Shane; Mooney, Walter D.

    2013-01-01

    We present a new set of contour maps of the seismic structure of South America and the surrounding ocean basins. These maps include new data, helping to constrain crustal thickness, whole-crustal average P-wave and S-wave velocity, and the seismic velocity of the uppermost mantle (Pn and Sn). We find that: (1) The weighted average thickness of the crust under South America is 38.17 km (standard deviation, s.d. ±8.7 km), which is ∼1 km thinner than the global average of 39.2 km (s.d. ±8.5 km) for continental crust. (2) Histograms of whole-crustal P-wave velocities for the South American crust are bi-modal, with the lower peak occurring for crust that appears to be missing a high-velocity (6.9–7.3 km/s) lower crustal layer. (3) The average P-wave velocity of the crystalline crust (Pcc) is 6.47 km/s (s.d. ±0.25 km/s). This is essentially identical to the global average of 6.45 km/s. (4) The average Pn velocity beneath South America is 8.00 km/s (s.d. ±0.23 km/s), slightly lower than the global average of 8.07 km/s. (5) A region across northern Chile and northeast Argentina has anomalously low P- and S-wave velocities in the crust. Geographically, this corresponds to the shallowly-subducted portion of the Nazca plate (the Pampean flat slab first described by Isacks et al., 1968), which is also a region of crustal extension. (6) The thick crust of the Brazilian craton appears to extend into Venezuela and Colombia. (7) The crust in the Amazon basin and along the western edge of the Brazilian craton may be thinned by extension. (8) The average crustal P-wave velocity under the eastern Pacific seafloor is higher than under the western Atlantic seafloor, most likely due to the thicker sediment layer on the older Atlantic seafloor.

  4. Oxygenation of a Cryogenian ocean (Nanhua Basin, South China) revealed by pyrite Fe isotope compositions

    NASA Astrophysics Data System (ADS)

    Zhang, Feifei; Zhu, Xiangkun; Yan, Bin; Kendall, Brian; Peng, Xi; Li, Jin; Algeo, Thomas J.; Romaniello, Stephen

    2015-11-01

    The nature of ocean redox chemistry between the Cryogenian Sturtian and Marinoan glaciations (ca. 663-654 Ma) is important for understanding the relationship between environmental conditions and the subsequent emergence and expansion of early animals. The Cryogenian-to-Ediacaran stratigraphic succession of the Nanhua Basin in South China provides a nearly complete sedimentary record of the Cryogenian, including a continuous record of interglacial sedimentation. Here, we present a high-resolution pyrite Fe isotope record for a ∼120-m-long drill-core (ZK105) through Sturtian glacial diamictites and the overlying interglacial sediments in the Nanhua Basin to explore changes in marine chemistry during the late Cryogenian. Our pyrite Fe isotope profile exhibits significant stratigraphic variation: Interval I, comprising middle to upper Tiesi'ao diamictites (correlative with the Sturtian glaciation), is characterized by light, modern seawater-like Fe isotope compositions; Interval II, comprising uppermost Tiesi'ao diamictites and the basal organic-rich Datangpo Formation, is characterized by an abrupt shift to heavier Fe isotope compositions; and Interval III, comprising organic-poor grey shales in the middle Datangpo Formation, is characterized by the return of lighter, seawater-like Fe isotope compositions. We infer that Interval I pyrite was deposited in a predominantly anoxic glacial Nanhua Basin through reaction of dissolved Fe2+ and H2S mediated by microbial sulfate reduction (MSR). The shift to heavier pyrite Fe isotope values in Interval II is interpreted as partial oxidation of ferrous iron to ferric iron and subsequent near-quantitative reduction and transformation of Fe-oxyhydroxides to pyrite through coupling with oxidation of organic matter in the local diagenetic environment. In Interval III, near-quantitative oxidation of ferrous iron to Fe-oxyhydroxides followed by near-quantitative reduction and conversion to pyrite in the local diagenetic environment

  5. Hydrology and water resources in Caspian Sea

    NASA Astrophysics Data System (ADS)

    Haddadi Moghaddam, Kourosh

    2016-10-01

    Precipitation is the main driver of the water balance variability of the water over space and time, and changes in precipitation have very important implications for hydrology and water resources. Variations in precipitation over daily, seasonal, annual, and decadal time scales influence hydrological variability over time in a catchment. Flood frequency is affected by changes in the year-to-year variability in precipitation and by changes in short-term rainfall properties. Desiccation of the Caspian Sea is one of the world's most serious ecosystem catastrophes. The Persian Sturgeon (Acipenser persicus) caught under 10 m depth using bottom trawl net by research vessel during winter 2012, summer and winter 2013 and spring 2014 in east, central and west of southern parts of Caspian Sea, then, their diets were investigated. During 136 trawling in the aimed seasons, Persian sturgeon with 1 to 2 years old and 179.67 × 0.2 g (body weight) and 29.97 ± 0.4 cm (Total length) captured. Examination of stomach contents in the sturgeon specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp. and Clupeonella delicatula), invertebrates belonging to the family Ampharetidae polychaeta worms including (Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.). Investigation on stomach contents of sturgeon Acipenser persicus caught under 10 m depth in 2012 to 2013 surveys showed that there is significant difference in the consumed food. The most food diversity have been observed in winter 2013, also Polychaeta is the primary consumed food and crustacean is the secondary one (P > 0.05), no new types of food (such as bony fishes or benthics) have been observed on food chain of Acipenser persicus and shows no significant difference (P > 0.05).

  6. Organic Carbon from the Deep Subsurface: The Witwatersrand Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Pullin, M. J.; Hendrickson, S.; Kieft, T. L.; Clewett, C. F.; Onstott, T. C.

    2011-12-01

    This work describes the isolation, fractionation, and chemical analysis of dissolved organic carbon from groundwater at 4,000 m below the surface in the Witwatersrand Basin in South Africa. The groundwater was accessed through mining boreholes in ultradeep gold mine shafts. The organic carbon was collected on XAD-8 and XAD-4 adsorption resins in situ and then transported to the surface for removal and clean-up. This work will present the C-14 age and δC-13 of the organic carbon. Solid state NMR analysis of the organic carbon will also provide insight into its chemical structure. Finally, we will discuss probable sources of the organic carbon and its biogeochemical cycling in the subsurface.

  7. Thorium Anomalies in the NW Quadrant of the South Pole-Aitken Basin

    NASA Technical Reports Server (NTRS)

    Haskin, Larry A.; McKinnon, William B.; Benner, Lance A. M.; Jolliff, Bradley L.

    2004-01-01

    The relatively high concentrations of Th near the Imbrium antipode in the South Pole-Aitken (SPA) basin might represent Imbrium ejecta, a consequence of convergence of Th-rich material ejected by the Imbrium impact that occurred in the Th-rich Procellarum KREEP Terrane. Here, we present landing positions for 7500 fragments ejected from Imbrium obtained by three-body (Earth-Moon-fragment) numerical integration for uniformly selected azimuthal launch positions, ejection angles of 45 deg, and velocities from 0.95 to 0.99 lunar escape. This provides an estimate of the density of infalling ejecta fragments to be expected in the vicinity of the Imbrium antipode. Similar calculations for 35 and 50 deg leave large empty regions surrounding the antipode.

  8. The nature and origin of Mafic Mound in the South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Moriarty, Daniel P.; Pieters, Carle M.

    2015-10-01

    "Mafic Mound" is a distinctive and enigmatic feature 75 km across and 1 km high near the center of the vast South Pole-Aitken Basin (SPA). Using several modern data sets, we characterize the composition, morphology, and gravity signature of the structure in order to assess its origin. Mafic Mound is found to exhibit a perched circular depression and a homogeneous high-Ca pyroxene-bearing composition. Several formation hypotheses based on known lunar processes are evaluated, including the possibilities that Mafic Mound represents (1) uplifted mantle, (2) SPA-derived impact melt, (3) a basalt-filled impact crater, or (4) a volcanic construct. Individually, these common processes cannot fully reproduce the properties of Mafic Mound. Instead, we propose a hybrid origin in which Mafic Mound is an edifice formed by magmatic processes induced by the formation and evolution of SPA. This form of nonmare volcanism has not previously been documented on the Moon.

  9. Structural control on lithofacies in the Zhu 1 depression, Pearl River Mouth Basin, South China Sea

    SciTech Connect

    Carnes, J.B.; Novitsky-Evans, J.C.; Schunk, D.J. )

    1994-07-01

    The structural framework of the Zhu 1 depression, Pearl River Mouth Basin, South China Sea, is expressed in terms of a half-graben rifting model, providing foundation for a predictive model of synrift lacustrine source rock distribution. The Zhu 1 depression includes a northern series of linked half grabens, a southern series of linked half grabens, and a central chain of intrabasinal ridges. The central ridge chain includes both horst blocks (termed high-relief accommodation zones or isolation ridges in the model) and antiforms (termed low-relief accommodation zones or interference ridges in the model). Major fluvial input was from the north, funneled into Zhu 1 through gaps (termed platforms in the model) created by offsets in the border faults of the northern series of half grabens. The central ridge chain is interpreted to have controlled sediment distribution within Zhu 1, periodically confining coarse terrigenous clastics within northern half grabens while lacustrine shales accumulated in southern half grabens.

  10. Regional comparison of syn- and post-rift sequences in salt and salt-free basins offshore Brazil and Angola/Namibia, South Atlantic

    NASA Astrophysics Data System (ADS)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2015-04-01

    The large South Atlantic basins offshore South America and Africa record a highly variable syn- to post-breakup tectono-stratigraphic development. The present-day diversity in the structural and sedimentary architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are i) the structural configuration of each margin segment at the time of break-up, ii) the post break-up geodynamic history including tectonics and magmatism, and iii) variations in the type, quantity and distribution of sediment input to the respective margin segment. Particularly the basins around the Rio Grande Rise - Walvis Ridge volcanic complex show a pronounced tectono-stratigraphic asymmetry both along the respective continental margin and across the Atlantic. Only a few attempts exist to establish a regional tectono-stratigraphic correlation framework across the South Atlantic Ocean, mainly because of the lack of data across entire margin segments and limited resolution of basin wide geophysics. Still unresolved issues particularly concern the explanation of the basin-specific geological evolution of respective margin segments along the same continental margin, as well as the correlation of conjugate basins and margin segments across the Atlantic Ocean. In our study we present interpretations and first-pass restorations of regional 2D seismic-reflectivity data from the large basins offshore Brazil (Pelotas Basin, Santos Basin, Campos Basin, Espirito Santo Basin), and offshore Namibia and Angola (Walvis Basin, Namibe Basin, Benguela Basin, Kwanza Basin), which represent four adjacent pairs of conjugate basins on both sides of the South Atlantic. Results are used to document and compare on a basin-scale the contrasting styles of rift and post-rift settings during and after the continental breakup.

  11. Characterisation of Landing Sites at the Rim of the Lunar South Pole Aitken Basin

    NASA Astrophysics Data System (ADS)

    Koebel, David; Bonerba, Michele; Wieser, Matthias; Homeister, Maren; Borowy, Carsten

    The lunar South polar region is of high scientific interest and advantageous in many aspects for exploration missions. The polar terrain is located at the rim of the Aitken Basin, being the largest impact crater in the solar system, where material from the lunar mantle has been ejected to the surface. This basin features a diameter of 2,500 km and variations in altitude as large as 14 km. Since the solar elevation never exceeds 1.5 at the pole, there exist mountain peaks in this area that are characterised by near eternal illumination. These summits provide a benign thermal environment for any long-term robotic or manned lander mission, and ideal conditions for photovoltaic power generation. The smaller impact craters in the polar region, on the other hand, possess depths with constant darkness. These craters are evidently harbouring water resources that remain conserved through the cryogenic temperatures inside them. The ice originates from the bombardment of comets throughout the billions of years after the formation of the lunar crust. For this terrain updated analyses of the solar illumination and ground station visibility conditions have been performed. These are based on the refined lunar digital elevation model provided by the Japanese Kaguya/Selene mission, originating from its LASER altimeter instrument. The resulting maps for the South polar region will be presented in this paper. Some considerations on the geology of interesting locations within the SPA are complemented. With these prerequisites, several possible landing sites for a future lunar mission have been selected. A detailed analysis of illumination timelines will be presented for these sites.

  12. Saline water in the Little Arkansas River Basin area, south-central Kansas

    USGS Publications Warehouse

    Leonard, Robert B.; Kleinschmidt, Melvin K.

    1976-01-01

    Ground water in unconsolidated deposits of Pleistocene age in part of the Little Arkansas River basin has been polluted by the influx of saline water. The source of the saline water generally is oil-field brine that leaked from disposal ponds on the land surface. Locally, pollution by saline water also has been caused by upwelling of oil-field brine injected under pressure into the "lost-circulation zone" of the Lower Permian Wellington Formation and, possibly, by leakage of brine from corroded or improperly cased disposal wells. Anomalously high concentrations of chloride ion in some reaches of the Little Arkansas River probably can be attributed to pollution by municipal wastes rather than from inflow of saline ground water. Hydraulic connection exists between the "lost-circulation zone" and unconsolidated deposits, as evidenced by the continuing development of sinkholes, by the continuing discharge of saline water through springs and seeps along the Arkansas River south of the Little Arkansas River basin and by changes in the chloride concentration in water pumped from wells in the "lost-circulation zone." The hydraulic head in the "lost-circulation zone" is below the base of the unconsolidated deposits, and much below the potentiometric surface of the aquifer in those deposits. Any movement of water, therefore, would be downward from the "fresh-water" aquifer to the saline "lost-circulation zone."

  13. Last Glacial mammals in South America: a new scenario from the Tarija Basin (Bolivia).

    PubMed

    Coltorti, M; Abbazzi, L; Ferretti, M P; Iacumin, P; Rios, F Paredes; Pellegrini, M; Pieruccini, P; Rustioni, M; Tito, G; Rook, L

    2007-04-01

    The chronology, sedimentary history, and paleoecology of the Tarija Basin (Bolivia), one of the richest Pleistocene mammalian sites in South America, are revised here based on a multidisciplinary study, including stratigraphy, sedimentology, geomorphology, paleontology, isotope geochemistry, and (14)C geochronology. Previous studies have indicated a Middle Pleistocene age for this classic locality. We have been able to obtain a series of (14)C dates encompassing all the fossil-bearing sequences previously studied in the Tarija Basin. The dated layers range in age from about 44,000 to 21,000 radiocarbon years before present (BP), indicating that the Tarija fauna is much younger than previously thought. Glacial advances correlated to marine isotopic stages (MIS) 4 and 2 (ca. 62 and 20 ka BP, respectively) are also documented at the base and at the very top of the Tarija-Padcaya succession, respectively, indicating that the Bolivian Altiplano was not dry but sustained an ice cap during the Last Glacial Maximum. The results of this multidisciplinary study enable us to redefine the chronological limits of the Tarija sequence and of its faunal assemblage and to shift this paleontological, paleoclimatological, and paleoecological framework to the time interval from MIS 4 to MIS 2. PMID:17180614

  14. Magnetic Signature of the Lunar South Pole-Aitken Basin: Character, Origin, and Age

    NASA Technical Reports Server (NTRS)

    Purucker, Michael E.; Head, James W., III; Wilson, Lionel

    2012-01-01

    A new magnetic map of the Moon, based on Lunar Prospector (LP) magnetometer observations, sheds light on the origin of the South Pole-Aitken Basin (SPA), the largest and oldest of the recognized lunar basins. A set of WNW-trending linear to arcuate magnetic features, evident in both the radial and scalar observations, covers much of a 1000 km wide region centered on the NW portion of SPA. The source bodies are not at the surface because the magnetic features show no first-order correspondence to any surface topographic or structural feature. Patchy mare basalts of possible late Imbrianage are emplaced within SPA and are inferred to have been emplaced through dikes, directly from mantle sources. We infer that the magnetic features represent dike swarms that served as feeders for these mare basalts, as evident from the location of the Thomson/ Mare Ingenii, Van de Graaff, and Leeuwenhoek mare basalts on the two largest magnetic features in the region. Modeling suggests that the dike zone is between 25 and 50 km wide at the surface, and dike magnetization contrasts are in the range of 0.2 A/m. We theorize that the basaltic dikes were emplaced in the lunar crust when a long-lived dynamo was active. Based on pressure, temperature, and stress conditions prevalent in the lunar crust, dikes are expected to be a dominantly subsurface phenomenon, consistent with the observations reported here.

  15. Deltaic Depositional Systems, Evolution Characteristics, and Petroleum Potential, Palaeogene Sub-Basin, South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Wang, Hua; Zhang, Guotao

    2015-04-01

    Deltaic depositional systems are detailed characterized by morphology and facies in a Palaeogene continental sub-basin of Beibuwan Basin, South China Sea. Based on examination of 435 m of conventional cores from 30 wells, three major types of deltaic facies have been recognized: delta, beach and shoreface. Morphology and facies asymmetry between the down-drift and the up-drift sides present a typical asymmetric delta system:1) the down-rift, sourced primarily by the feeding river, are influenced by mixed river and wave processes. Deposits on this side are muddy and consist of barrier, bar, bay-fill, and bayhead delta facies with variable bioturbation intensity; 2)the up-rift, in contrast, is sourced by a second sediment source and typically consists of laterally continuous sandy beach and shoreface facies. Finally, two fundamentally different depositional models are established and reflect a different style of sequence stratigraphic patterns: 1) Multiple-stage faults slopes developed in the down-rift side feed fine grained sediment into two stages channelized front deltaic system; 2) Flexure slope break of the up-rift side, combining with deeper gradual slopes, conversely, feed coarser grained sediment from larger drainages into sandy beach and shoreface systems. Such a distinction has well explained the differentiation of the proven hydrocarbon reserves because the up-rift consists of well-sorted, mature, and laterally continuous homogeneous beach-shoreface reservoirs, whereas the down-rift, in contrast, is muddier and consists of less continuous, less mature, heterolithic reservoirs. The Delta asymmetry concepts and models don't only challenge the traditional definition of deltas in Fushan sub-basin, but also provides strong theoretical support for the future exploration. This process-based model may be applicable to many deep-water settings and provides a framework within which to interpret the stratigraphic and spatial distribution of these complex deposits.

  16. Late tectonic uplift of an inverted oceanic basin in South East Asia: the case of Palawan Island (western Philippines)

    NASA Astrophysics Data System (ADS)

    Meresse, F.; Savva, D.; Pubellier, M.; Steuer, S.; Franke, D.; Cordey, F.; Muller, C.; Sapin, F.; Mouly, B.; Auxiètre, J.-L.

    2012-04-01

    The elongated island of Palawan, bounded by two marginal basins, the South China Sea to the North and the Sulu Sea to the South is composed of remnants of an inverted basin (Proto-South China Sea) thrusted onto the margin of a continental terrane which rifted away from the Chinese-Vietnamese margin. Based on field observations coupled with seismic and drill-holes data, our study focuses on the structural architecture of the island in order to decipher the geodynamic evolution of the southern margin of the South China Sea. Structurally, the Palawan Island consists of: (i) the Palawan wedge, which extends towards the South China Sea is composed of deformed slope to deep ocean deposits of Cretaceous (north Palawan) to Tertiary (central and south Palawan) ages. This accretionnary wedge is characterized by small wavelength folds of mainly NE-SW trend. Offshore, the unconformable Middle-Late Miocene Tabon limestones unit postdates the last stages of the Palawan wedge growth/setting; (ii) On top of this wedge lie thrust slices of ophiolite bodies comprising ribbon cherts of Albian age as indicated by radiolarians.; these bodies are likely to be relicts of the now-subducted Proto South China Sea; (iii) The central and southern parts of the Palawan island are characterized by a large wavelength antiform of NE-SW trend. This structure is sealed by the slightly tilted Early Pliocene marls unit; (iv) The island also presents necking zones bordered by N-S trending transform faults. This area witnessed the geodynamic evolution of the South East Asia which consists of a succession of opening/closure of oceanic basins and block accretions. The Palawan Island therefore results of the closing of the Proto-South China Sea which once formed both the Palawan accretionary wedge and the overlying ophiolite tectonic slices. During a later compressive event, the rifted continental margin which composes the basement of the Island was inverted, inducing the uplift and the large scale folding

  17. U-Pb zircon ages from the southwestern Karoo Basin, South Africa - Implications for the Permian-Triassic boundary

    USGS Publications Warehouse

    Fildani, A.; Weislogel, A.; Drinkwater, N.J.; McHargue, T.; Tankard, A.; Wooden, J.; Hodgson, D.; Flint, S.

    2009-01-01

    U-Pb ages determined using sensitive high-resolution ion microprobe-reverse geometry on 205 single-grain zircons from 16 ash beds within submarine fan deposits of the Ecca Group provide the first evidence of a marine Permian-Triassic (P-T) boundary in the Karoo Basin of South Africa. These U-Pb ages provide an objective basis for correlating the deep-marine sediments of the southwest Karoo Basin with fluvial-deltaic deposits in the central and eastern parts of the basin where the P-T boundary is recorded in a diverse macrofauna. Furthermore, these new zircon ages and their correlation imply asymmetric subsidence and variable sedimentation rates across the basin. ?? 2009 Geological Society of America.

  18. Origin and interpretation of knickpoints in the Big South Fork River basin, Kentucky-Tennessee

    NASA Astrophysics Data System (ADS)

    Phillips, Jonathan D.; McCormack, Sarah; Duan, Jidan; Russo, Joseph P.; Schumacher, Anne M.; Tripathi, Ganesh N.; Brockman, Ruth B.; Mays, Adam B.; Pulugurtha, Sruti

    2010-01-01

    This study investigates the causes of knickpoints and knickzones in the bedrock-controlled streams of the Big South Fork River basin in Kentucky and Tennessee. Knickpoints in the Big South Fork River area vary in form and apparent origins. While some are likely related to base level change and incision in the Cumberland River drainage system, the locations and drainage relations of the knickpoints are not consistent with transmission of an incision signal throughout the network. Local controls predominate in forming steeper channel segments, with no single factor dominant. Knickpoints in the study area are characterized by polygenesis and multiple causality, though several archetypes can be identified. These include rock fall rapids, created by mass wasting from adjacent valley slopes; structurally controlled headwater cliffs; and lithological knickpoints. A fourth category, local incision knickpoints, may be attributable to a variety of factors influencing force:resistance relationships. These results imply that the simple presence of a knickpoint cannot be attributed to any particular cause or history without consideration of the local controls. This further implies that factors such as the spacing of knickpoints may not be an indication of migration rates or that migration has even occurred. However, the analysis of individual profile convexities can shed light on various controls (such as lithology and structure) and other processes (such as valley side mass wasting and local bed incision) important in evolution of fluvially dissected landscapes.

  19. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from analogue modelling

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao

    2016-10-01

    How the South China Sea rifted has long been a puzzling question that is still debated, particularly with reference to the Southwest Sub-basin (SWSB). Analogue modelling remains one of the most useful tools for testing rift models and processes. Here, we present and discuss a series of analogue modelling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical results were compiled to provide realistic constraints to test the experimental results and interpretations. A heterogeneous lithosphere model with a varied lithospheric structure showed tectono-morphological features similar to the natural case of the SWSB, indicating that the initial thermal condition and rheological stratification of the lithosphere should have a dominant effect on the rifting process of the SWSB. Rigid tectonic blocks existed in the continental margin, such as the Macclesfield Bank and the Reed Bank, and they played important roles in both the shaping of the continent-ocean boundary and the coupling between the crust and mantle. The initial thermal condition and rheological stratification of the lithosphere under the South China Sea controlled the propagated rifting process of the SWSB. Extension was centred on the deep troughs between the rigid blocks, and the break-up occurred in these areas between them. The westward rifting propagation is best explained with a heterogeneous lithosphere model characterized by varied lithospheric structure, and it was responsible for producing the V-shaped configuration of the SWSB.

  20. Extension and magmatism across the Suwanee Suture and South Georgia Basin from the SUGAR seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Shillington, D. J.; Lizarralde, D.; Harder, S. H.; Marzen, R.; Kaip, G.; Accardo, N. J.; Gibson, J. C.; Nauer, A.

    2015-12-01

    The South Georgia Basin was at the center of the most recent sequence of continental collision and rifting events to shape eastern North America. It is the largest of the failed Mesozoic rift basins that formed during the breakup of Pangea, and it straddles the Suwannee Suture, the only well-defined remnant of the Alleghenian suture that joined North America and Gondwana. The South Georgia Basin also lies at the center of the Central Atlantic Magmatic Province (CAMP). It is thus an excellent location to examine the importance of magmatism and pre-existing structures on continental extension. Here we present preliminary results from the SUwanee Suture and GA Rift basin (SUGAR) project, an active-source seismic refraction project to image the crustal structure across these features. In March 2014, we acquired data along SUGAR Line 1, a ~325-km-long, NW-SE oriented profile that crossed the Suwanee Suture and western part of South Georgia Basin. The profile was densely instrumented with 1193 single-channel RekTek 125A seismographs ("Texans") spaced at ~250 m. The sources were 100 to 1800 lb shots spaced at ~20-50 km. In August 2015, we will acquire data along SUGAR Lines 2 and 3. SUGAR Line 2 is a ~450-km-long profile spanning the eastern part of the South Georgia Basin and two possible locations for the Suwanee Suture. We will deploy 1983 "Texans" spaced at 250 m and detonate seventeen 400 to 1600 lb shots spaced at ~16-50 km. SUGAR Line 3 targets the Brunswick magnetic anomaly; we plan to instrument a 100-km-long profile with 700 Texans spaced at 150 m and eleven 200 lb shots spaced at ~10 km. Over 68 students participated in field work for SUGAR. Preliminary models of SUGAR Line 1 indicate that the crust thins to ~33 km beneath the South Georgia Basin. Anomalously high lower crustal velocities occur beneath the basin in the area of the greatest crustal thinning and may represent mafic intrusions from CAMP/synrift magmatism. We will present initial velocity models of

  1. Water resources in the Big Lost River Basin, south-central Idaho

    USGS Publications Warehouse

    Crosthwaite, E.G.; Thomas, C.A.; Dyer, K.L.

    1970-01-01

    The Big Lost River basin occupies about 1,400 square miles in south-central Idaho and drains to the Snake River Plain. The economy in the area is based on irrigation agriculture and stockraising. The basin is underlain by a diverse-assemblage of rocks which range, in age from Precambrian to Holocene. The assemblage is divided into five groups on the basis of their hydrologic characteristics. Carbonate rocks, noncarbonate rocks, cemented alluvial deposits, unconsolidated alluvial deposits, and basalt. The principal aquifer is unconsolidated alluvial fill that is several thousand feet thick in the main valley. The carbonate rocks are the major bedrock aquifer. They absorb a significant amount of precipitation and, in places, are very permeable as evidenced by large springs discharging from or near exposures of carbonate rocks. Only the alluvium, carbonate rock and locally the basalt yield significant amounts of water. A total of about 67,000 acres is irrigated with water diverted from the Big Lost River. The annual flow of the river is highly variable and water-supply deficiencies are common. About 1 out of every 2 years is considered a drought year. In the period 1955-68, about 175 irrigation wells were drilled to provide a supplemental water supply to land irrigated from the canal system and to irrigate an additional 8,500 acres of new land. Average. annual precipitation ranged from 8 inches on the valley floor to about 50 inches at some higher elevations during the base period 1944-68. The estimated water yield of the Big Lost River basin averaged 650 cfs (cubic feet per second) for the base period. Of this amount, 150 cfs was transpired by crops, 75 cfs left the basin as streamflow, and 425 cfs left as ground-water flow. A map of precipitation and estimated values of evapotranspiration were used to construct a water-yield map. A distinctive feature of the Big Lost River basin, is the large interchange of water from surface streams into the ground and from the

  2. Asynchronous timing of extension and basin formation in the South Rhodope core complex, SW Bulgaria, and northern Greece

    NASA Astrophysics Data System (ADS)

    Stübner, Konstanze; Drost, Kerstin; Schoenberg, Ronny; Böhme, Madelaine; Starke, Jessica; Ehlers, Todd A.

    2016-01-01

    Upper crustal extensional structures range from steep normal faults to shallow-dipping detachments. The relationship between extension and formation of synkinematic hanging wall basins including their relative timing is not well understood. The South Rhodope core complex, Southern Balkans, has experienced extension for >40 Ma leading to a number of extensional structures and Cenozoic sedimentary basins. We present new bedrock and basin detrital zircon and apatite (U-Th-Sm)/He ages from the Pirin and Rila Mountains and the Sandanski basin. Results identify three episodes of Cenozoic extension in SW Bulgaria accommodated by (1) the Eocene/Oligocene Mesta detachment; (2) the early to middle Miocene Gorno Spanchevo fault (circa 18-15 Ma), which is the northern prolongation of the Strymon low-angle detachment; and (3) the late Miocene West Pirin fault (≤10 Ma). Detachment faulting on the Strymon fault accommodated tens of kilometers of ENE-WSW extension and created ~1500 m topographic relief, but because the resulting hillslopes were gentle (≤10°), extension did not lead to enhanced footwall erosion or formation of a hanging wall basin. In contrast, the West Pirin normal fault resulted in mostly vertical motion of its footwall causing steep topography, rapid erosion, and formation of the synrift Sandanski basin. Digital topographic analysis of river channel profiles identifies the latest episodes of deformation including westward tilting of the Sandanski and Strymon basins and Quaternary N-S extension. This study demonstrates that basin formation in the South Rhodope core complex is related to normal faulting postdating the main episode of crustal stretching by detachment faulting.

  3. Basin-Scale Transport of Hydrothermal Iron, Manganese and Aluminum Across the Eastern South Pacific

    NASA Astrophysics Data System (ADS)

    Sedwick, P. N.; Resing, J. A.; Sohst, B. M.; Jenkins, W. J.; German, C. R.; Moffett, J. W.

    2014-12-01

    The U.S. GEOTRACES Eastern Pacific Zonal Transect cruise (GEOTRACES GP06) examined the water-column distribution of trace elements between Peru and Tahiti, crossing the southern East Pacific Rise (EPR) midway along the cruise track. Shipboard measurements made along this ocean section reveal the mid-depth lateral transport of hydrothermal dissolved iron (dFe), manganese (dMn) and aluminum (dAl) over a distance of more than 4,000 km, from the EPR westward into the deep South Pacific basin. Post-cruise measurements of the conservative hydrothermal tracer helium-3 indicate the loss of at least 85% of the hydrothermal dFe over a distance of ~80 km west from the ridge axis, presumably as a result of oxidation, scavenging and precipitation. Further west of the ridge axis, dFe and excess helium-3 (3Hexs) are linearly correlated (r2 = 0.99), showing a more than 4-fold conservative dilution of hydrothermal dFe over a distance of ~4000 km. This behavior may reflect the lateral transport of iron as relatively unreactive, colloidal oxyhydroxides; ongoing analyses of cruise samples by other groups will provide data to test this hypothesis. The loss of hydrothermal dMn relative to 3Hexs extends over a greater distance than for dFe, as far as ~250 km to the west of the ridge axis, beyond which dMn exhibits nearly conservative behavior. The hydrothermal dAl anomaly appears to extend over 3,000 km west of the EPR, and is not readily explained based on the known composition of ridge-axis vent fluids. The linear dFe versus 3Hexs relationship in the off-axis hydrothermal plume has a slope of 5.6 x 106 mol/mol, which falls roughly between values estimated for the western South Pacific and the South Atlantic basins. If we assume that our dFe and 3He data are generally representative of mid-ocean ridge hydrothermal emissions, then the estimated global hydrothermal 3He efflux of 530 mol/y yields an effective hydrothermal dFe input of 2.9 Gmol/y to the ocean interior.

  4. Mid-Cretaceous submarine fans of the southwest Bredasdorp basin, South Africa

    SciTech Connect

    Gilbert, C. )

    1991-03-01

    Mid-Cretaceous lowstand systems tracts, containing varying thicknesses of sandstone, have been identified in the E-G subbasin, south-central Bredasdorp basin, offshore South Africa. These lowstand tracts overlie a type 1 unconformity of Albian age, related to erosion of submarine channels into the lower continental slope. Five boreholes drilled in this area to date were located either at the break of continental slope on this unconformity or slightly distal thereto. Four wells were designed primarily to test Late Jurassic-Early Cretaceous rift-fill sequences beneath the drift onset (Gondwanaland breakup) unconformity. The fifth borehole tested mid-Cretaceous lowstand sandstones, following reappraisal of their reservoir quality and hydrocarbon shows, based on the earlier boreholes. Gamma-ray log motifs together with seismic interpretations, petrographic evidence from cores, and sidewall cores and cuttings permit the interpretation of various subenvironments, from proximal feeder channel to distal supra-fan lobe settings of a deep-marine fan or fans. It is proposed that these fans represent the first phase of sedimentation on the Albian type 1 unconformity surface during conditions of falling sea level. Sediment, possibly eroded from highstand fan deltas or shelf sands on a partially exposed shelf to the south, was transported down erosional submarine channels. A proximal source and high gradients favored the high sand:mud ratio encountered in these wells. Local tectonic activity of short duration along faults parallel to the Agulhas fracture zone may have contributed to gradient steepening. Latest drilling results have upgraded similar plays distal to erosional channels in the immediate area.

  5. Chemical quality of water in the Walnut River basin, south-central Kansas

    USGS Publications Warehouse

    Leonard, Robert B.

    1972-01-01

    Improper disposal of oil-field brine and other wastes has adversely affected the naturally diverse chemical quality of much of the water in the Walnut River basin, south-central Kansas. The basin is an area of about 2,000 square miles in the shape of a rough triangle with its apex toward the south. The Whitewater River, a principal tributary, and the Walnut River below its junction with the Whitewater River flow southward toward the Arkansas River along courses nearly coincident with the contact of the Chase and overlying Sumner Groups of Permian age. The courses of many minor tributaries are parallel to a well-developed joint system in the Permian rock. Thick interbedded limestone and shale of the Chase Group underlie the more extensive, eastern part of the basin. Natural waters are dominantly of the calcium bicarbonate type. Shale and subordinate strata of limestone, gypsum, and dolomite of the Sumner Group underlie the western part of the basin. Natural waters are dominantly of the calcium sulfate type. Inflow from most east-bank tributaries dilutes streamflow of the Walnut River; west-bank tributaries, including the Whitewater River, contribute most of the sulfate. Terrace deposits and alluvial fill along the stream channels are assigned to the Pleistocene and Holocene Series. Calcium bicarbonate waters are common as a result of the dissolution of nearly ubiquitous fragments of calcareous rock, but the chemical quality of the water in the discontinuous aquifers depends mainly on the quality of local recharge. Concentrations of dissolved solids and of one or more ions in most well waters exceeded recommended maximums for drinking water. Nearly all the ground water is hard to very hard. High concentrations of sulfate characterize waters from gypsiferous aquifers; high concentrations of chloride characterize ground waters affected by drainage from oil fields. Extensive fracture and dissolution of the Permian limestones facilitated pollution of ground water by oil

  6. Risk assessment of drain valve failure in the K-West basin south loadout pit

    SciTech Connect

    MORGAN, R.G.

    1999-06-23

    The drain valve located in the bottom of the K-West Basin South Loadout Pit (SLOP) could provide an additional leak path from the K Basins if the drain valve were damaged during construction, installation, or operation of the cask loading system. For the K-West Basin SLOP the immersion pail support structure (IPSS) has already been installed, but the immersion pail has not been installed in the IPSS. The objective of this analysis is to evaluate the risk of damaging the drain valve during the remaining installation activities or operation of the cask loading system. Valve damage, as used in this analysis, does not necessarily imply large amounts of the water will be released quickly from the basin, rather valve damage implies that the valve's integrity has been compromised. The analysis process is a risk-based uncertainty analysis where best engineering judgement is used to represent each variable in the analysis. The uncertainty associated with each variable is represented by a probability distribution. The uncertainty is propagated through the analysis by Monte Carlo convolution techniques. The corresponding results are developed as a probability distribution and the risk is expressed in terms of the corresponding complementary cumulative distribution function (''risk curve''). The total risk is the area under the ''risk curve''. The risk of potentially dropping a cask into or on the IPSS and damaging the drain valve is approximately 1 x 10{sup -4} to 2 x 10{sup -5} per year. The risk of objects falling behind the IPSS and damaging the valve is 3 x 10{sup -2} to 6 x 10{sup -3} per year. Both risks are expressed as drain value failure frequencies. The risk of objects falling behind the IPSS and damaging the valve can be significantly reduced by an impact limiter and/or installing a gating or plate over the area bounded by the back of the IPSS and the wall of the SLOP. With either of these actions there is a 90 percent confidence that the frequency of drain valve

  7. The Spatio-Temporal Variation of Hydrochemical Characteristics in Yamzhog Yumco Basin, South Tibet

    NASA Astrophysics Data System (ADS)

    Zhe, M.; Zhang, X.

    2015-12-01

    From 2009 to 2014, more than 300 water samples of 52 sites from the five lakes and seven inflow rivers of Yumzhog Yumco Basin, South Tibet have been collected, and the hydrochemical types, sources of ions, and the spatial-temporal variation in waters analyzed annually. The basin waters are slightly saline or fresh because of the different sources of water replenishment, and are hardest water with weak alkalinity. The hydrochemical types of Yamzhog Yum Co, Puma Yum Co, Bajiu Co, Kongmu Co, and Chen Co are SO42--HCO3--Mg2+-Na+, HCO3--SO42--Mg2+, SO42--Mg2+-Na+, SO42--HCO3--Ca2+, and SO42--Na+-Mg2+-Ca2+, respectively. As for rivers, HCO3- together with SO42- is the major anion, and Ca2+ is the dominant cation. The weathering of evaporites and carbonatites, along with the evaporation-crystallization plays a significant role in the difference of hydrochemical compositions. In addition, anthropogenic impacts, such as the rapid tourism development and the utilization of Yamzhog Yumco hydropower should not be ignored. Compared with the salinity in 1984, Puma Yum Co has been desalinated obviously during 2009-2014 as a result of the accelerated glacier melt caused by the global warming. Furthermore, the Cl- concentration has decreased consequently with the increased evaporation from 2009 to 2014. Yamzhog Yum Co, the largest lake in this basin with a complex zigzag bank and a different inflow river system, exhibits remarkable spatial variation for its surface waters. The mineralization degree, and the concentration of Mg2+ and (Na++K+) are low with high concentration of Ca2+ in the river mouth entering into Yamzhog Yum Co. Moreover, the irregular changes in vertical direction can be attributed to the strong wind and comparatively abundant rainfall during the sampling period. To sum up, the combined impacts of environmental changes and human activities can account for the spatial distribution and temporal evolution of hydrochemical characteristics in Yamzhog Yumco Basin.

  8. Reasons and Predictions of The Caspian Sea Water Level Fluctuations: Impact of Climate Factors and Man's Activities.

    NASA Astrophysics Data System (ADS)

    Erlich, M.; Shiklomanov, I.; Yezhov, A.; Georgievsky, V.; Shalygin, A.

    The Caspian Sea - the largest lake in the world - has no connection with the Ocean and is lower than its surface. Fluctuations of the Sea level are very significant: during the period of instrumental observations (since 1830) the level amplitude was 3.78 m with maximum of -25.22 m in 1882 and minimum of -29.00 m in 1978. These fluctuations lead to a great damage for the economy of five countries sharing its coast (Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan). Deep knowledge of hydrological and hydrodynamic Sea regime and scientifically justified forecasts of possible changes in its level, taking into account variability in climate and future climate change, are re- quired for undertaking urgent measures for protection of coastal territories. The inter- national research project CASSEAS, carried out in 1997-2000 within the framework of the INCO-COPERNICUS programme by the scientists of 5 countries: France, Rus- sia, Germany, Turkmenistan and UK, was devoted to these problems. Research made within the Project made it possible to get new precise data on all water balance com- ponents of the Caspian Sea for 1880-1996; moreover, all water balance components for 1940-1996 were computed independently. It was shown that the Sea level fluctua- tions depended on the water balance almost completely. Assessment of possible future runoff changes in the Caspian Sea basin was made using the mathematical model of runoff formation developed at the SHI. Several scenarios from a range of GCMs and on the basis of paleoclimatic reconstructions were used as the models of the future climate for the nearest 3 decades. Besides changes in climate characteristics, three variants were accepted for the future water use in the basins of rivers discharging to the Caspian Sea. All scenarios gave similar results for changes in annual river inflow to the Caspian Sea: its increase would be from 5% to 10% by 2030. The same scenarios, used to estimate changes in precipitation onto the Sea

  9. Sedimentary model for Eocene exotic blocks of carbonates and turbiditic carbonate deposits in the South Sistan Basin, SE Iran

    NASA Astrophysics Data System (ADS)

    Mohammadi, Ali; Burg, Jean-Pierre; Bernoulli, Daniel

    2016-04-01

    The N-S-trending Sistan Suture Zone in east Iran results from collision of the Lut Block to the west with the Afghan Block to the east. Extensive Eocene turbiditic sequences with numerous exotic carbonate olistholiths and carbonate debris flows in the southern part of the Sistan Basin (so-called Neh Accretionary Wedge) were deposited in a deep-marine environment. Litho-biostratigraphy of the exotic carbonate blocks and carbonate debris flows with surrounding sandstones aims to develop a paleoenvironmental model for the South Sistan sedimentary basin. The olistholiths, of Early to Middle Eocene age, are derived from one or more carbonate platforms including inner shelf (protected platform), shelf margin (coral reefs, skeletal sand bars) and upper slope deposits. In addition, the terrigenous turbidites that form the background sediments of the basinal deposits are interlayered with carbonate mass-flow deposits, lime turbidites and scarcer pelagic limestones with planktonic foraminifera of Eocene age showing that the mass-flow events contemporaneous with platform evolution. The absence of terrigenous detritus and of volcanic material in the platform limestones and related mass-flow deposits suggests that the carbonate platform was presumably located on the Kuh-e-Birk passive margin, to the southwest of the Sistan Basin. Key words: South Sistan Basin, sedimentary model, Eocene, olistostrome, carbonate platform

  10. Gazetteer of hydrologic characteristics of streams in Massachusetts; coastal river basins of the South Shore and Buzzards Bay

    USGS Publications Warehouse

    Wandle, S.W.; Morgan, M.A.

    1984-01-01

    The coastal river basins include the minor river basins draining into Massachusetts Bay along the South Shore or into Buzzards Bay. The larger of these basins are the North, South, Jones, Wareham, Weweantic, Mattapoisett, Acushnet, and Slocums River basins. Drainage areas, using the latest available 1:24,000 scale topographic maps, were computed for data collection sites. Statistics on streamflow characteristics computed with a new data base are presented for six gaged streams. Daily-flow records through 1982 were used to compute annual and monthly flow statistics, duration of daily flow values, and the annual 7-day mean low flow at the 2-year and 10-year recurrence intervals. Seven-day low-flow statistics are presented for 49 partial-record sites and procedures used to determine the hydrologic characteristics of the basin are summarized. This gazetteer will aid in the planning and siting of water-resources related activities and will provide a common data base for governmental agencies and the engineering and planning communities. (USGS)

  11. Lithospheric Velocity Structure of the Anatolain plateau-Caucasus-Caspian Regions

    SciTech Connect

    Gok, R; Mellors, R J; Sandvol, E; Pasyanos, M; Hauk, T; Yetirmishli, G; Teoman, U; Turkelli, N; Godoladze, T; Javakishvirli, Z

    2009-04-15

    Anatolian Plateau-Caucasus-Caspian region is an area of complex structure accompanied by large variations in seismic wave velocities. Despite the complexity of the region little is known about the detailed lithospheric structure. Using data from 29 new broadband seismic stations in the region, a unified velocity structure is developed using teleseismic receiver functions and surface waves. Love and Rayleigh surface waves dispersion curves have been derived from event-based analysis and ambient-noise correlation. We jointly inverted the receiver functions with the surface wave dispersion curves to determine absolute shear wave velocity and important discontinuities such as sedimentary layer, Moho, lithospheric-asthenospheric boundary. We combined these new station results with Eastern Turkey Seismic Experiment results (29 stations). Caspian Sea and Kura basin underlained by one of the thickest sediments in the world. Therefore, short-period surface waves are observed to be very slow. The strong crustal multiples in receiver functions and the slow velocities in upper crust indicate the presence of thick sedimentary unit (up to 20 km). Crustal thickness varies from 34 to 52 km in the region. The thickest crust is in Lesser Caucasus and the thinnest is in the Arabian Plate. The lithospheric mantle in the Greater Caucasus and the Kura depression is faster than the Anatolian Plateau and Lesser Caucasus. This possibly indicates the presence of cold lithosphere. The lower crust is slowest in the northeastern part of the Anatolian Plateau where Holocene volcanoes are located.

  12. A 500-year history of floods in the semi arid basins of south-eastern Spain

    NASA Astrophysics Data System (ADS)

    Sánchez García, Carlos; Schulte, Lothar; Peña, Juan Carlos; Carvalho, Filpe; Brembilla, Carla

    2016-04-01

    Floods are one of the natural hazards with higher incidence in the south-eastern Spain, the driest region in Europe, causing fatalities, damage of infrastructure and economic losses. Flash-floods in semi arid environments are related to intensive rainfall which can last from few hours to days. These floods are violent and destructive because of their high discharges, sediment transport and aggradation processes in the flood plain. Also during historical times floods affected the population in the south-eastern Spain causing sever damage or in some cases the complete destruction of towns. Our studies focus on the flood reconstruction from historical sources of the Almanzora, Aguas and Antas river basins, which have a surface between 260-2600 km2. We have also compiled information from the Andarax river and compared the flood series with the Guadalentín and Segura basins from previous studies (Benito et. al., 2010 y Machado et al., 2011). Flood intensities have been classified in four levels according to the type of damage: 1) ordinary floods that only affect agriculture plots; 2) extraordinary floods which produce some damage to buildings and hydraulic infrastructure; 3) catastrophic floods which caused sever damage, fatalities and partial or complete destruction of towns. A higher damage intensity of +1 magnitude was assigned when the event is recorded from more than one major sub-basin (stretches and tributaries such as Huércal-Overa basin) or catchment (e.g. Antas River). In total 102 incidences of damages and 89 floods were reconstructed in the Almanzora (2.611 km2), Aguas (539 km2), Antas (261 km2) and Andarax (2.100 km2) catchments. The Almanzora River was affected by 36 floods (1550-2012). The highest events for the Almanzora River were in 1580, 1879, 1973 and 2012 producing many fatalities and destruction of several towns. In addition, we identified four flood-clusters 1750-1780, 1870-1900, 1960-1977 and 1989-2012 which coincides with the periods of

  13. Pesticides in surface water from three agricultural basins in south-central Georgia, 1993-97

    USGS Publications Warehouse

    Hatzell, H.H.

    1996-01-01

    Twenty-two of 43 pesticides analyzed were detected in 128 water samples collected from Tucsawhatchee Creek, the Little River, and the Withlacoochee River. These streams drain agricultural basins in south-central Georgia and were sampled from March 1993 through June 1995. Herbicides were detected more frequently than insecticides. The most frequently detected herbicides were atrazineand metolachlor and the most frequently detected insecticide was carbaryl. Pesticide concentrations in the three streams were low and did not exceed U.S. Environmental Protection Agency drinking water standards. The maximum pesticide concentration was 2.6 ug/L (micrograms per liter) for propargite, a miticide detected in only one sample. The maximum concentrations of the remaining 21 pesticides were less than 0.25 ug/L. The median concentrations were equal to the method detection limit for all pesticides except atrazine (0.008 ug/L) and metolachlor (0.012 ug/L). The ratio of herbicidedetections to nondetections was largest in the planting season, smaller in the harvest season and smallest in the fallow season for the three basins.The same pattern existed for the insecticide ratios in the Little River and the Withlacoochee River. Pairwise correlations between concentrations of atrazine and metolachlor and four parameters (discharge, and concentrations of dissolved organiccarbon, suspended organic carbon, and suspended fine sediment) were evaluated for each stream. The strongest correlations existed between metolachlor and mean daily discharge and metolachlor and fine sediment in the Withlacoochee River. The only significant correlation for the Little River was between atrazine and suspended fine sediment.

  14. Testing orbital forcing in the Eocene deltaic sequences of the South-Pyrenean Foreland Basins.

    NASA Astrophysics Data System (ADS)

    Garcés, Miguel; López-Blanco, Miguel; Valero, Luis; Beamud, Elisabet; Pueyo-Morer, Emilio; Rodríguez-Pinto, Adriana

    2014-05-01

    Paleoclimate proxy records from marine pelagic sediments show that a link exists between long-period orbital cyclicity and the pattern of high latitude glaciations. Thus, a sound possibility exist that transgressive-regressive third-order sequences from shallow marine environments reflect long-period orbital (glacioeustatic) forcing, as suggested from a variety of shallow marine settings of different ages, from Mesozoic to Paleogene. In this study we aim at testing the role of the 400 kyr eccentricity cycle in the sequential organization of the Late Eocene deltaic sequences of the Belsue-Atares Formation, in the Jaca-Pamplona Basin. The overall record spans from latest Lutetian to early Priabonian and consists of nearly 1000 meters of siliciclastic deltaic to mixed platform sequences of various scales. Very notorious lateral changes in both stratigraphic thickness and sedimentary facies witness the synkinematic character of these sediments, deposited simultaneously to intrabasinal fold growth. A magnetostratigraphy based chronostratigraphic framework is used, first, to determine the age and duration of the sequences and, second, to establish a robust correlation with other deltaic sequences within the south-pyrenean foreland. The long-distance correlation exercise is used to discriminate between local (tectonic) and global (climatic) forcing factors, under the assumption that climate signature is synchronous, while tectonic forcing is prone to yield diachronic units at basin scale. Astronomical tuning with the 400-kyr cycle of the eccentricity solution of the Earth orbit is attempted on the basis of derived magnetostratigraphic age constrains. Our results suggest that transgressive (regressive) trends correlate with maxima (minima) of eccentricity cycle, a phase-relationship which is compatible with a base-level (accommodation) driven forcing.

  15. Salt-related tectonics in the eastern Sichuan Basin, South China

    NASA Astrophysics Data System (ADS)

    Gu, Zhidong; Yin, Jifeng; Yuan, Miao; Zhai, Xiufen

    2015-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze platform of South China, and East Sichuan is situated between Huaying Mountain fault and Qiyue Mountain fault. The surface Jura type folds are very famous with barrier parallel folds, but the cause of folds formation have not been completely understood. Stratigraphic units are composed of thick competent flexural layers separately by relatively thin incompetent ductile layers that can act as detachments.Multiple detachment layers are developed in the eastern Sichuan and result in distinct structural domains. In addition to the basal, Triassic and Silurian system detachment layers, we recognize a regionally extensive salt layer in the Middle and Lower Cambrian. The recognition of salt layer is by the synthetical studies of outcrop, drilling well, and chaotic seismic reflection configuration. The Middle and Lower Cambrian salt forms a tectonic domain boundary that can be observed by seismic reflection profile in subsurface. The stratigraphic intervals above and below the salt develop characteristic salt-related tectonics. And the folds formation is by flow in and flow out of salt movement of the Middle and Lower Cambrian and flexural slip and grouding of the overlying units. Above the salt, the thrust fault-related folds were generated by the contractional action from southeast to northwest, including the fault-bend fold, fault-propagation fold, and thrust wedge fold, and so on. Below the salt, the broad anticlines were formed due to the basal detachment. Hydrocarbon traps are formed above and below the salt, and they are potential gas exploration domains in the eastern Sichuan Basin.

  16. Lunar impact basins: New data for the western limb and far side (Orientale and South Pole-Aitken basins) from the first Galileo flyby

    NASA Astrophysics Data System (ADS)

    Head, James W.; Murchie, Scott; Mustard, John F.; Pieters, Carle M.; Neukum, Gerhard; McEwen, Alfred; Greeley, Ronald; Nagel, Engelbert; Belton, Michael J. S.

    1993-09-01

    Compositional aspects of impact basin materials can be analyzed using multispectral image data acquired by the Galileo solid state imaging (SSI) experiment during the December 1990 lunar encounter. These data provide important information on the spectral properties of the western lunar limb and parts of the far side. The SSI images cover the wavelength range 0.4-1.0 μm, allowing measurement of spectral slope and estimation of the strength of the 1 μm absorption due to iron in the mafic minerals olivine and pyroxene. Among deposits of the 930-km-diameter Orientale basin, exterior ejecta comprising the Hevelius Formation is relatively homogeneous and spectrally similar to mature Apollo 16 soils, suggesting an upper crustal source. The centrally located Maunder Formation is distinct from the younger mare basalts but comparable to the Hevelius Formation in its spectral reflectance properties, supporting an interpretation as basin impact melt. The Montes Rook Formation, located in an annulus between the Maunder and the Hevelius, shows a slightly stronger mafic absorption and may be the deepest crustal material excavated. The distal Orientale deposits show local mafic enhancements (in the Schiller-Schickard and Mendel-Rydberg regions) interpreted to represent pre-Orientale mare deposits, or cryptomaria, intermixed with overlying basin ejecta. In this case, maria of sizes comparable to those presently observed were widespread in this region before the Orientale impact. Mixing-model analyses are consistent with the ballistic erosion and sedimentation model for ejecta emplacement in the distal regions beyond the continuous ejecta deposit. On the southern lunar farside, a high area with an enhanced mafic absorption corresponds to the interior and rim of the pre-Nectarian South Pole-Aitken impact basin, 2000-2500 km in diameter. The anomaly is interpreted to be due to several factors, including excavation into the more mafic lower crust, and the presence of extensive early

  17. Hydraulic conductivity of near-surface alluvium in the vicinity of Cattlemans Detention Basin, South Lake Tahoe, California

    USGS Publications Warehouse

    Green, Jena M.; Henkelman, Katherine K.; Caskey, Rachel M.

    2004-01-01

    Cattlemans detention basin, South Lake Tahoe, California is designed to capture and reduce urban runoff and pollutants originating from developed areas before entering Cold Creek, which is tributary to Trout Creek and to Lake Tahoe. The effectiveness of the basin in reducing sediment and nutrient loads currently is being assessed with a five-year study. Hydraulic conductivity of the alluvium near the detention basin is needed to estimate ground-water flow and subsurface nutrient transport. Hydraulic conductivity was estimated using slug tests in 27 monitoring wells that surround the detention basin. For each test, water was poured rapidly into a well, changes in water-level were monitored, and the observed changes were analyzed using the Bouwer and Rice method. Each well was tested one to four times. A total of 24 wells were tested more than once. Of the 24 wells, the differences among the tests were within 10 percent of the average. Estimated hydraulic conductivities of basin alluvium range from 0.5 to 70 feet per day with an average of 17.8 feet per day. This range is consistent with the sandy alluvial deposits observed in the area of Cattlemans detention basin.

  18. Evaluation of PARIS performance in the South Central Coast Air Basin. Volume 2. Technical report. Final report

    SciTech Connect

    Douglas, S.G.; Daly, C.; Moore, G.E.; Myers, T.C.

    1991-12-01

    The primary goal of the study was to compare PARIS model performance in simulating ozone in the South Central Coast Air Basin (SCCAB) for 22-24 September 1985 using alternative wind fields. One wind field was generated by the Diagnostic Wind Model (DWM), and the other by the Colorado State University Mesoscale Model (CSUMM). The overall objective of the South Central Coast Cooperative Aerometric Monitoring Program (SCCCAMP) project was to develop a means of assessing the aggregate impact of offshore petroleum industry sources on onshore ozone (O3) and nitrogen dioxide (NO2) concentrations.

  19. Evaluation of PARIS performance in the South Central Coast Air Basin. Volume 1. Executive Summary. Final report

    SciTech Connect

    Douglas, S.G.; Daly, C.; Moore, G.E.; Myers, T.C.

    1991-12-01

    The primary goal of the study was to compare PARIS model performance in simulating ozone in the South Central Coast Air Basin (SCCAB) for 22-24 September 1985 using alternative wind fields. One wind field was generated by the Diagnostic Wind Model (DWM), and the other by the Colorado State University Mesoscale Model (CSUMM). The overall objective of the South Central Coast Cooperative Aerometric Monitoring Program (SCCCAMP) project was to develop a means of assessing the aggregate impact of offshore petroleum industry sources on onshore ozone (O3) and nitrogen dioxide (NO2) concentrations.

  20. Constraining the vertical surface motions of the Hampshire Basin, south England During the Cenozoic

    NASA Astrophysics Data System (ADS)

    Smith, Philip; England, Richard; Zalasiewicz, Jan

    2016-04-01

    The potential effect of rising sea level on the UK has received considerable attention in recent years. However, the ongoing long-term changes in surface topography of the UK driven by regional tectonics and the mechanisms responsible are not fully understood. It is thought that glacial loading/unloading is the primary influence. However, this is inconsistent with present-day vertical surface motions recorded from Continuous Global Positioning Stations (CGPS) across the UK. The lateral variations in the present day motions are too complex to be explained by glacial isostatic rebound. We are investigating the hypothesis that the vertical motions of SE England also reflect the long term tectonic history by backstripping the Cenozoic geological record. So far the Paleogene stratigraphic record of the Hampshire basin in southern England has been investigated and using a series of deep boreholes that reach the chalk basement, a 2-D backstripping method has been applied. Subsidence analysis of cliff sections and boreholes reveal the Hampshire Basin was tectonically subsiding at a steady rate from 56.5Ma and any major periods of uplift and denudation to the present day state must have occurred from the mid Oligocene onwards. At this time the northern and western regions of the UK were believed to be uplifting as evidenced by heavy mineral transport directionns and sediment drainage patterns. A rapid increase in tectonic subsidence from 42Ma recorded by the three Isle of Wight sections in close proximity to an existing Variscan fault, thought to reactivate as a thrust during the Cenozoic, suggests a compressional stress regime in this region. The stress pattern observed from the tectonic subsidence data and evidence from drainage patterns supports a model in which the UK was uplifting in the north and west while the south east was subsiding. As this pattern is similar to the present day vertical surface motions and pre-dates glaciation, we propose glacial unloading as a

  1. Geology, thermal maturation, and source rock geochemistry in a volcanic covered basin: San Juan sag, south-central Colorado

    USGS Publications Warehouse

    Gries, R.R.; Clayton, J.L.; Leonard, C.

    1997-01-01

    The San Juan sag, concealed by the vast San Juan volcanic field of south-central Colorado, has only recently benefited from oil and gas wildcat drilling and evaluations. Sound geochemical analyses and maturation modeling are essential elements for successful exploration and development. Oil has been produced in minor quantities from an Oligocene sill in the Mancos Shale within the sag, and major oil and gas production occurs from stratigraphically equivalent rocks in the San Juan basin to the south-west and in the Denver basin to the northeast. The objectives of this study were to identify potential source rocks, assess thermal maturity, and determine hydrocarbon-source bed relationships. Source rocks are present in the San Juan sag in the upper and lower Mancos Shale (including the Niobrara Member), which consists of about 666 m (2184 ft) of marine shale with from 0.5 to 3.1 wt. % organic carbon. Pyrolysis yields (S1 + S2 = 2000-6000 ppm) and solvent extraction yields (1000-4000 ppm) indicate that some intervals within the Mancos Shale are good potential source rocks for oil, containing type II organic matter, according to Rock-Eval pyrolysis assay. Oils produced from the San Juan sag and adjacent part of the San Juan basin are geochemically similar to rock extracts obtained from these potential source rock intervals. Based on reconstruction of the geologic history of the basin integrated with models of organic maturation, we conclude that most of the source rock maturation occurred in the Oligocene and Miocene. Little to no maturation took place during Laramide subsidence of the basin, when the Animas and Blanco Basin formations were deposited. The timing of maturation is unlike that of most Laramide basins in the Rocky Mountain region, where maturation occurred as a result of Paleocene and Eocene basin fill. The present geothermal gradient in the San Juan sag is slightly higher (average 3.5??C/100 m; 1.9??F/100 ft) than the regional average for southern Rocky

  2. Decadal biogeochemical history of the south east Levantine basin: Simulations of the river Nile regimes

    NASA Astrophysics Data System (ADS)

    Suari, Yair; Brenner, Steve

    2015-08-01

    The south eastern Mediterranean is characterized by antiestuarine circulation which leads to extreme oligotrophic conditions. The Nile river that used to transport fresh water and nutrients into the basin was dammed in 1964 which led to a drastic reduction of fresh water fluxes, and later, changes in Egyptian agriculture and diet led to increased nutrient fluxes. In this paper we present the results of simulations with a biogeochemical model of the south eastern Mediterranean. Four experiments were conducted: (1) present day without riverine inputs; (2) Nile before damming (pre-1964); (3) post-damming 1995 Nile; and (4) fresh water and nutrient discharges of Israeli coastal streams. The present day input simulation (control run) successfully reproduced measured nutrient concentrations, with the exception of simulated chlorophyll concentrations which were slightly higher than observed. The pre-1964 Nile simulation showed a salinity reduction of 2 psu near the Egyptian coast and 0.5 psu along the Israeli coast, as well as elevated chlorophyll a concentrations mostly east of the Nile delta and north to Cyprus. The spring bloom extended from its present peak during February-March to a peak during February-May. The 1995 Nile simulation showed increased chlorophyll a concentrations close to the Egyptian coast. The Israeli coastal stream simulation showed that the effect of the Israeli coastal stream winter flow on chlorophyll converged to control concentrations within about one month, demonstrating the stability and sensitivity of the model to external forcing. The results of this study demonstrate the significance of fresh water fluxes in maintaining marine productivity, which may have large scale effects on the marine ecosystem.

  3. Estimated water use and availability in the South Coastal Drainage Basin, southern Rhode Island, 1995-99

    USGS Publications Warehouse

    Wild, Emily C.; Nimiroski, Mark T.

    2005-01-01

    The South Coastal Drainage Basin includes approximately 59.14 square miles in southern Rhode Island. The basin was divided into three subbasins to assess the water use and availability: the Saugatucket, Point Judith Pond, and the Southwestern Coastal Drainage subbasins. Because there is limited information on the ground-water system in this basin, the water use and availability evaluations for these subbasins were derived from delineated surface-water drainage areas. An assessment was completed to estimate water withdrawals, use, and return flow over a 5-year study period from 1995 through 1999 in the basin. During the study period, one major water supplier in the basin withdrew an average of 0.389 million gallons per day from the sand and gravel deposits. Most of the potable water is imported (about 2.152 million gallons per day) from the adjacent Pawcatuck Basin to the northwest. The estimated water withdrawals from the minor water suppliers, which are all in Charlestown, during the study period were 0.064 million gallons per day. The self-supplied domestic, industrial, commercial, and agricultural withdrawals from the basin were 0.574 million gallons per day. Water use in the basin was 2.874 million gallons per day. The average return flow in the basin was 1.190 million gallons per day, which was entirely from self-disposed water users. In this basin, wastewater from service collection areas was exported (about 1.139 million gallons per day) to the Narragansett Bay Drainage Basin for treatment and discharge. During times of little to no recharge, in the form of precipitation, the surface- and ground-water system flows are from storage primarily in the stratified sand and gravel deposits, although there is flow moving through the till deposits at a slower rate. The ground water discharging to the streams, during times of little to no precipitation, is referred to as base flow. The PART program, a computerized hydrograph-separation application, was used at the

  4. Thorium Abundances of Basalt Ponds in South Pole-Aitken Basin: Insights into the Composition and Evolution of the Far Side Lunar Mantle

    NASA Astrophysics Data System (ADS)

    Hagerty, J. J.; Lawrence, D. J.; Hawke, B. R.

    2011-03-01

    We used forward modeling of Lunar Prospector thorium (Th) data derived from basalts in South Pole-Aitken basin to demonstrate that large expanses of basalt could be reliably used to obtain compositional information about the far side lunar mantle.

  5. Assessment of undiscovered oil and gas resources of the Williston Basin Province of North Dakota, Montana, and South Dakota, 2010

    USGS Publications Warehouse

    ,

    2011-01-01

    Using a geology-based assessment method, the U.S. Geological Survey estimated mean undiscovered volumes of 3.8 billion barrels of undiscovered oil, 3.7 trillion cubic feet of associated/dissolved natural gas, and 0.2 billion barrels of undiscovered natural gas liquids in the Williston Basin Province, North Dakota, Montana, and South Dakota. The U.S. Geological Survey (USGS) recently completed a comprehensive oil and gas assessment of the Williston Basin, which encompasses more than 90 million acres in parts of North Dakota, eastern Montana, and northern South Dakota. The assessment is based on the geologic elements of each total petroleum system (TPS) defined in the province, including hydrocarbon source rocks (source-rock maturation, hydrocarbon generation, and migration), reservoir rocks (sequence stratigraphy and petrophysical properties), and hydrocarbon traps (trap formation and timing). Using this geologic framework, the USGS defined 11 TPS and 19 Assessment Units (AU).

  6. What role does crustal heterogeneity play on continental break-up; the interplay of a foldbelt, rift system and ocean basin in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Paton, Douglas; Mortimer, Estelle; Hodgson, Neil

    2015-04-01

    Although extensively studied, two key questions remain unanswered regarding the evolution of the southern South Atlantic. Firstly, where is the Cape Foldbelt (CFB) in offshore South Africa? The CFB is part of the broader Gonwanian Orogeny that prior to South Atlantic rifting continued into the Ventana Foldbelt of Argentina but to date its location in the offshore part of South Africa remains enigmatic. Secondly, the conjugate rift basin to South Africa is the Colorado Basin in Argentina but why does it trend east-west despite its perpendicular orientation to the Atlantic spreading ridge? Current plate models and structural understands cannot explain these fundamental questions. We use newly acquired deep reflection seismic data in the Orange Basin, South Africa, to develop a new structural model for the southern South Atlantic. We characterise the geometry of the Cape Foldbelt onshore and for the first time correlate it into the offshore. We show that it has a north-south trend immediately to the north of the Cape Peninsula but then has a syntaxis (Garies syntaxis) that results in a change to an east-west orientation. This forms the missing jigsaw piece of the Atlantic reconstruction as this is directly beside the restored Colorado Basin. When considered within the pre-break up structural configuration our observations imply that prior to the main phase of Atlantic rifting in the Mezosoic there was significant variation in crustal geometry incorporating the Orange Basin of South Africa, the Colorado Basin and the Gariep Belt of Namibia. These faults were active during Gondwana rifting, but the Colorado rift failed resulting in the present day location of the South Atlantic. Not only do our results improve our understanding of the evolution of the South Atlantic ocean, they highlight the importance of differentiating between early rift evolution and strain localisation during the subsequent rift phase prior to seafloor spreading.

  7. Geologic Mapping of the Lunar South Pole, Quadrangle LQ-30: Volcanic History and Stratigraphy of Schroedinger Basin

    NASA Technical Reports Server (NTRS)

    Mest, S. C.; Berman, D. C.; Petro, N. E.

    2009-01-01

    In this study we use recent images and topographic data to map the geology and geomorphology of the lunar South Pole quadrangle (LQ-30) at 1:2.5M scale [1-4] in accordance with the Lunar Geologic Mapping Program. Mapping of LQ-30 began during Mest's postdoctoral appointment and has continued under the PG&G Program, from which funding became available in February 2009. Preliminary map-ping and analyses have been done using base materials compiled by Mest, but properly mosaicked and spatially registered base materials are being compiled by the USGS and should be received by the end of June 2009. The overall objective of this research is to constrain the geologic evolution of the lunar South Pole (LQ-30: 60deg -90deg S, 0deg - +/-180deg ) with specific emphasis on evaluation of a) the regional effects of basin formation on the structure and composition of the crust and b) the spatial distribution of ejecta, in particular resulting from formation of the South Pole-Aitken (SPA) basin and other large basins. Key scientific objectives include: 1) Constraining the geologic history of the lunar South Pole and examining the spatial and temporal variability of geologic processes within the map area. 2) Constraining the vertical and lateral structure of the lunar regolith and crust, assessing the distribution of impact-generated materials, and determining the timing and effects of major basin-forming impacts on crustal structure and stratigraphy in the map area. And 3) assessing the distribution of resources (e.g., H, Fe, Th) and their relationships with surface materials.

  8. Sedimentary record and climatic implications of recurrent deformation in the Tian Shan: Evidence from Mesozoic strata of the north Tarim, south Junggar, and Turpan basins, northwest China

    SciTech Connect

    Hendrix, M.S.; Graham, S.A.; Sobel, E.R.

    1992-01-01

    Detailed stratigraphic, sedimentologic, paleocurrent, and subsidence analyses were conducted on Mesozoic nonmarine sedimentary sections of the south Junggar, north Tarim, and Turpan basins, Xinjang Uygur Autonomous Region, northwest China. These three basins have been foreland basins throughout the Mesozoic and Cenozoic eras, as demonstrated by asymmetrically distributed basinwide sediment accumulations, foreland-style subsidence profiles, and a variety of outcrop and subsurface facies data. Mesozoic paleocurrent indicators measured in the south Junggar and north Tarim basins, as well as Mesozoic sandstone compositions from both basins, indicate that the intervening Tian Shan has existed as a positive physiographic feature partitioning the two basins throughout Mesozoic and Cenozoic time. Paleocurrent, facies, and subsurface isopach data suggest that the Turpan basin was established as a discrete feature by the Early Jurassic period. The timing and style of depositional systems within the north Tarim Mesozoic depocenter, the south Junggar Mesozoic depocenter, and the central Turpan basin are remarkably similar. Upper Triassic strata of each basin consist of alluvial conglomerate and associated braided-fluvial sandstone and siltstone which fine upward into lower through Middle Jurassic, locally organic-rich, meandering-fluvial, and lacustrine strata. Upper Jurassic braided-fluvial red beds in each basin are overlain by a distinct pulse of uppermost Jurassic alluvial conglomerate. Lower Cretaceous exposures consist of fine-grained red beds in north Tarim and Turpan and interbedded red and gray shale with local silty carbonates in south Junggar. Upper Cretaceous strata of the north Tarim and south Junggar basins are composed of alluvial conglomerate with associated braided-fluvial sandstone and siltstone. 94 refs., 17 figs.

  9. A paleomagnetic and relative paleointensity record from the Argentine Basin (western South Atlantic Ocean) for the last ~125 kyrs

    NASA Astrophysics Data System (ADS)

    Heil, C. W., Jr.; Stoner, J. S.; St-Onge, G.; King, J. W.

    2015-12-01

    The paucity of paleomagnetic records from the western South Atlantic Ocean presents a significant gap in our understanding of the spatial variations in geomagnetic field dynamics as they relate to the occurrence of geomagnetic excursions and changes in field strength. As such, high quality records from this region can help build upon Holocene observations and extend the geographic and temporal data coverage for spherical harmonic models. To that end, we present paleomagnetic directional (inclination) and strength (relative paleointensity) records from two cores from the Argentine Basin (RC11-49 and RC16-88). Although the cores were collected more than 40 years ago, the sediments appear to hold a stable remanence and reliable magnetic directions, as evidenced by their reproducibility between the two cores that are separated by ~25 km. The records show evidence of 4 excursional features in the uppermost 16-m of the sediments from the basin. A comparison of the relative paleointensity records from these cores to the South Atlantic Paleointensity Stack (SAPIS) (Stoner et al., 2002) and the relative paleointensity record from ODP Site 1089 (Stoner et al., 2003) indicate that the sediments reliably record relative changes in geomagnetic field intensity and suggests that the longest record (RC11-49) spans the last ~125 kyrs. Our results indicate that the sediments of the Argentine Basin are an important sedimentary archive of geomagnetic field behavior and strength at least through the Holocene and Late Pleistocene and highlight the need for further studies of cores within the basin.

  10. Mixed volcanogenic-lithogenic sources for Permian bauxite deposits in southwestern Youjiang Basin, South China, and their metallogenic significance

    NASA Astrophysics Data System (ADS)

    Yu, Wenchao; Algeo, Thomas J.; Du, Yuansheng; Zhang, Qilian; Liang, Yuping

    2016-07-01

    Bauxite deposits at the base of the Upper Permian Heshan Formation in the Youjiang Basin, South China, contain zircons with dominant age peaks at 263-262 Ma. During the Middle to Late Permian, the Youjiang Basin consisted of a number of isolated and attached carbonate platforms separated by inter-platform troughs. The bauxite deposits are limited to the isolated carbonate platform facies and are not present on attached carbonate platforms and inter-platform troughs. Discriminant plots based on the trace element composition of the zircons indicate a combination of within-plate/anorogenic and arc-related/orogenic sources. Geochemical and isotopic data suggest that the metallogenic materials of the bauxite deposit came from felsic volcanic rocks of the Emeishan Large Igneous Provence (ELIP) in South China and from the Truong Son volcanic arc located between the South China and Indochina cratons. The northwestern and southeastern parts of the Youjiang Basin received larger amounts of ELIP detritus and volcanic arc detritus, respectively. Coarser siliciclastic material in proximal attached carbonate platform and inter-platform trough settings was delivered by rivers, but finer siliciclastics that accumulated on distally located carbonate platforms in isolated deep-water areas was probably transported by wind.

  11. Heavy-duty truck emissions in the South Coast Air Basin of California.

    PubMed

    Bishop, Gary A; Schuchmann, Brent G; Stedman, Donald H

    2013-08-20

    California and Federal emissions regulations for 2007 and newer heavy-duty diesel engines require an order of magnitude reduction in particulate matter and oxides of nitrogen spurring the introduction of new aftertreatment systems. Since 2008, four emission measurement campaigns have been conducted at a Port of Los Angeles location and an inland weigh station in the South Coast Air Basin of California. Fuel specific oxides of nitrogen emissions at the Port have decreased 12% since 2010 while infrared opacity (a measure of particulate matter) remained low, showing no diesel particulate filter deterioration. The weigh station truck's fuel specific oxides of nitrogen emission reductions since 2010 (18.5%) almost double the previous three year's reductions and are the result of new trucks using selective catalytic reduction systems. Trucks at the weigh station equipped with these systems have a skewed oxides of nitrogen emissions distribution (half of the emissions were from 6% of the measurements) and had significantly lower emissions than similarly equipped Port trucks. Infrared thermographs of truck exhaust pipes revealed that the mean temperature observed at the weigh station (225 ± 4.5 °C) was 70 °C higher than for Port trucks, suggesting that the catalytic aftertreatment systems on trucks at our Port site were often below minimum operating temperatures.

  12. Microbial evidence for sulfur cycling in the deep subsurface of the Witwatersrand Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Gihring, T. M.; Moser, D. P.; Dollhopf, M.; Balkwill, D. L.; Davidson, M. M.; Onstott, T. C.; Pfiffner, S. M.; Macalady, J. L.

    2004-05-01

    The continental deep subsurface harbors a heterogeneous community of microorganisms that have yet to be well understood. The gold mines of the Witwatersrand Basin in South Africa provide relatively easy access to this environment and have been integral to recent attempts to characterize subsurface microbiology. Molecular evidence for the biogeochemical cycling of sulfur has been detected in fissure water from Merriespruit and Driefontein mines. PCR amplification, cloning, and sequencing of adenosine-5'-phosphosulfate reductase (APS) and 16S rRNA genes were used to assess the composition of sulfur metabolizing microbial populations. Sequences closely related to APS reductase genes of the sulfur-oxidizing bacterium Allochromatium vinosum were detected in the Merriespruit Mine sample. APS reductase gene libraries from the Driefontein Mine sample were dominated by sequences with high identity to known sulfate-reducing bacteria. Phylogenetic analyses of 16S rRNA sequences indicated the presence of Thiobacillus-related species (known S-oxidizing organisms) in the Merriespruit sample, while Driefontein 16S rRNA clone libraries were dominated by sequences with high identity to known sulfate-reducing organisms in the delta-Proteobacteria and Firmicutes lineages. This study provides some of the first environmental APS sequences from sulfur-oxidizing bacteria and sheds new light on the organisms participating in sulfur-cycling in the deep subsurface.

  13. Sulfur geochemistry across a terrestrial Permian-Triassic boundary section in the Karoo Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Maruoka, T.; Koeberl, C.; Hancox, P. J.; Reimold, W. U.

    2003-01-01

    Concentrations of sulfur and carbon, and isotopic compositions of sulfur were determined in sedimentary rocks from a section across the terrestrial Permian-Triassic (P-Tr) boundary in the northern Karoo Basin, South Africa. High concentrations of sulfide produced by sulfate-reducing bacteria were found in the sedimentary rocks at and just below the perceived P-Tr boundary. The ratios of organic carbon to sulfide of the sedimentary rocks with high concentrations of sulfide are relatively constant and similar to those of marine environments. This means that the enhanced accumulation of sulfide is a result of the enrichment of sulfate in the water. As the sulfide concentrations do not correlate with concentrations of any major elements indicative of weathering intensity, the supply of sulfate was independent of environmental factors, such as temperature and CO 2 concentrations in the atmosphere, which control weathering intensity. Therefore, it is reasonable to consider that the sulfate might have been supplied to the freshwater directly as acid rain by an event such as a bolide impact or a volcanic eruption. The absence of evidence for an impact event in the geological record, though, favors volcanic input as the cause of the acid rain.

  14. Development of a model-based flood emergency management system in Yujiang River Basin, South China

    NASA Astrophysics Data System (ADS)

    Zeng, Yong; Cai, Yanpeng; Jia, Peng; Mao, Jiansu

    2014-06-01

    Flooding is the most frequent disaster in China. It affects people's lives and properties, causing considerable economic loss. Flood forecast and operation of reservoirs are important in flood emergency management. Although great progress has been achieved in flood forecast and reservoir operation through using computer, network technology, and geographic information system technology in China, the prediction accuracy of models are not satisfactory due to the unavailability of real-time monitoring data. Also, real-time flood control scenario analysis is not effective in many regions and can seldom provide online decision support function. In this research, a decision support system for real-time flood forecasting in Yujiang River Basin, South China (DSS-YRB) is introduced in this paper. This system is based on hydrological and hydraulic mathematical models. The conceptual framework and detailed components of the proposed DSS-YRB is illustrated, which employs real-time rainfall data conversion, model-driven hydrologic forecasting, model calibration, data assimilation methods, and reservoir operational scenario analysis. Multi-tiered architecture offers great flexibility, portability, reusability, and reliability. The applied case study results show the development and application of a decision support system for real-time flood forecasting and operation is beneficial for flood control.

  15. The Noucaplac-1 Survey, South Fiji Basin: an International Collaboration Combining UNCLOS and Science Objectives

    NASA Astrophysics Data System (ADS)

    Roest, W. R.; Herzer, R.; Barker, D. H.; Lafoy, Y.

    2005-12-01

    The UN Convention on the Law of the Sea allows coastal states to claim a legal continental shelf beyond the 200 nautical miles that constitutes the Exclusive Economic Zone. One of the opportunities presented by UNCLOS article 76 is to align essential - and expensive - data acquisition in poorly mapped shelf regions with scientific research interests, thus maximising data value. The Noucaplac-1 survey that took place in August 2004 in the South Fiji Basin is an example of collaboration between neighboring states aiming to address both UNCLOS article 76 requirements and scientific objectives. The Noucaplac-1 survey was designed by the French EXTRAPLAC (reasoned extension of the continental shelf) program to identify the natural prolongation of the New Caledonian territory along the Loyalty Ridge. At the same time, the environs of the potential extended continental shelf claim was identified by the New Zealand collaborators as a key region for study to improve understanding of the regional tectonic evolution and the survey scope was modified accordingly. This contribution describes the data acquired on board the French RV L'Atalante during the Noucaplac-1 cruise. In addition to the multibeam bathymetric data collected with the EM-12 multibeam echo sounder and showing basement tectonic fabric at the sea floor, high-speed seismic data are of particular interest, as they allow the interpretation of basement morphology in this area that is covered by relatively sparse sediments. Regional magnetic data provide additional evidence for distinct morphotectonic regions that may help a New Caledonian extended continental shelf claim

  16. Potential for atmospheric-driven lead paint degradation in the South Coast Air Basin of California.

    PubMed

    Cohan, Alexander J; Edwards, Rufus D; Kleinman, Michael T; Dabdub, Donald

    2009-12-01

    Exposure to lead in paint or lead residues in house dust and soil is one of the leading environmental risks to the health of children in the United States. Components of photochemical smog can increase the degradation of binders in lead paint, leading to increased release of lead pigment granules to hands in surface contact or for deposition in house dust and soil. This study uses photochemical air quality modeling to map areas susceptible to increased lead paint degradation as a result of photochemical atmospheric pollutants to prioritize areas of concern. Typical air quality episodes in the South Coast Air Basin of California (SoCAB) are modeled for the 1970s, 1980s, and 1990s. Results indicate that large areas of the SoCAB were susceptible to atmospheric-driven accelerated lead paint degradation. Inner city urban areas from central Los Angeles to Azusa and most of Orange County had the highest susceptibility to accelerated lead paint degradation, followed by inland locations near the San Bernardino Mountains. This study identifies photochemical oxidant gases as contributors to greater lead release from indoor painted surfaces in urban areas.

  17. Drought effects on water quality in the South Platte River Basin, Colorado

    USGS Publications Warehouse

    Sprague, L.A.

    2005-01-01

    Twenty-three stream sites representing a range of forested, agricultural, and urban land uses were sampled in the South Platte River Basin of Colorado from July through September 2002 to characterize water quality during drought conditions. With a few exceptions, dissolved ammonia, Kjeldahl nitrogen, total phosphorus, and dissolved orthophosphate concentrations were similar to seasonal historical levels in all land use areas during the drought. At some agricultural sites, decreased dilution of irrigation return flow may have contributed to higher concentrations of some nutrient species, increased primary productivity, and higher dissolved oxygen concentrations. At some urban sites, decreased dilution of base flow and wastewater treatment plant effluent may have contributed to higher dissolved nitrite-plus-nitrate concentrations, increased primary productivity, and higher dissolved oxygen concentrations. Total pesticide concentrations in urban and agricultural areas were not consistently higher or lower during the drought. At most forested sites, decreased dilution of ground water-derived calcium bicarbonate type base flow likely led to elevated pH and specific-conductance values. Water temperatures at many of the forested sites also were higher, contributing to lower dissolved oxygen concentrations during the drought.

  18. Depositional Record of the Bagua Basin, Northern Peru: Implications for Climate and Tectonic Evolution of Tropical South America

    NASA Astrophysics Data System (ADS)

    Moreno, F.; George, S. W. M.; Williams, L. A.; Horton, B. K.; Garzione, C. N.

    2015-12-01

    The Andes Mountains exert critical controls on the climate, hydrology, and biodiversity of South America. The Bagua Basin, a low elevation (400-600 m) intermontane basin in northern Peru, offers a unique opportunity to study the ecological, climatic, and structural evolution of the western topographic boundary of the Amazonian foreland. Situated between the Marañon fold-thrust belt of the Western Cordillera and basement block uplifts of the Eastern Cordillera, the Bagua region contains a protracted, semi-continuous record of Triassic through Pleistocene sedimentation. Whereas Triassic-Cretaceous marine deposits were potentially related to extension and regional thermal subsidence, a Paleocene-Eocene shift to shallow marine and fluvial systems marks the onset of foreland basin conditions. Oligocene-Miocene sedimentation corresponds to a braided-meandering fluvial system with exceptional development of paleosols. In this study, we use new detrital zircon U-Pb geochronologic and oxygen stable isotopic datasets to establish a chronology of pre-Andean and Andean processes within the Bagua Basin. Detrital zircon geochronology provides constraints on when the Western and Eastern cordilleras shed sediments into the basin. Syndepositional zircons within Eocene, Oligocene and Miocene strata provide key age control for a previously poorly constrained depositional chronology. Preliminary results suggest a dramatic provenance shift in which Paleocene deposits contain almost exclusively cratonic populations (500-1600 Ma) whereas Eocene deposits show a mix of syndepositional zircons from the magmatic arc, recycled Mesozoic zircons, and cratonic zircon populations. Oxygen stable isotopes (δ18O) of carbonate nodules from Neogene paleosols will help elucidate when the Eastern Cordillera became an orographic barrier intercepting moisture from the Amazon basin to the east. Together, these records will help uncover the history of tectonics and climate interaction in tropical South

  19. Characteristics of hydrothermal sedimentation process in the Yanchang Formation, south Ordos Basin, China: Evidence from element geochemistry

    NASA Astrophysics Data System (ADS)

    He, Cong; Ji, Liming; Wu, Yuandong; Su, Ao; Zhang, Mingzhen

    2016-11-01

    Hydrothermal sedimentation occurred in the Triassic Yanchang Formation, Ordos Basin, China. However, their macroscopic features at the scale of the stratum and hydrothermal sources still lack correlational research. This paper performed element geochemical study on a large number of core samples collected from the Yanchang Formation of a new drilling well located in the south Ordos Basin. The SiO2/(K2O + Na2O) vs. MnO/TiO2 crossplot and Fe vs. Mn vs. (Cu + Co + Ni) × 10 ternary diagram demonstrate that the Yanchang stratum in the study area has, in general, hydrothermal components. The Al/(Al + Fe + Mn) and (Fe + Mn)/Ti ratios of the core samples range from 0.34 to 0.84 and 4.81 to 50.54, averaging 0.66 and 10.67, respectively, indicating that the stratum is a set of atypical hydrothermal sedimentation with much terrigenous input. Data analysis shows that the hydrothermal source in the study area was from the deep North Qinling Orogen around the south margin of the basin, where some active tectonic and volcanic activities took place, rather than from the relatively stable internal basin. Early Indosinian movement and volcanic activities activated basement faults around the southern margin of the basin, providing vents for the deep hydrothermal fluid upwelling. The hydrothermal indicators suggest that the study area experienced 4 episodes of relatively stronger hydrothermal activity, namely during the Chang 10, Chang 9-1, Chang 7-3 and Chang 6-2 periods. We also propose a new hydrothermal sedimentation model of hydrothermal fluids overflowing from basin margin faults, for the Yanchang Formation, which is reported here for the first time.

  20. Flood of August 11–16, 2010, in the South Skunk River Basin, central and southeast Iowa

    USGS Publications Warehouse

    Barnes, Kimberlee K.; Eash, David A.

    2012-01-01

    Severe thunderstorm activity during August 8–11, 2010 in central and southeast Iowa resulted in major flooding from August 11–16, 2010, in the South Skunk River Basin. Rain gages at Ames and Story City recorded 96-hour rainfall amounts of 9.61 and 8.70 inches, respectively. The majority of the rainfall occurred during a 52-hour period, beginning late at night on August 8. Within the South Skunk River Basin, peak discharges of 14,800 cubic feet per second (annual flood-probability estimate of 0.2 to 1 percent) at the 05470000 South Skunk River near Ames, Iowa streamgage; of 36,200 cubic feet per second (annual flood-probability estimate of less than 0.2 percent) at the 05471000 South Skunk River below Squaw Creek near Ames, Iowa streamgage (both on August 11, 2010); and of 24,000 cubic feet per second (annual flood-probability estimate of 0.2 to 1 percent) at 05471050 South Skunk River at Colfax, Iowa streamgage on August 14 are the largest floods on record for these sites. Peak discharges at 05470500 Squaw Creek at Ames, Iowa streamgage of 22,400 cubic feet per second (annual flood-probability estimate of less than 0.2 percent) on August 11; and at 05471500 South Skunk River near Oskaloosa, Iowa streamgage, of 25,200 cubic feet per second (annual flood- probability estimate of 1 to 2 percent) on August 16 are the second highest floods on record. This report provides a description of the watershed, the thunderstorms, the flooding, and a profile of high-water marks measured at 20 locations along the South Skunk River between County Road V67/280th Avenue, northeast of Ollie in Keokuk County and West Riverside Road in Ames, a distance of 128 river miles.

  1. Recent Mission Datasets Shed New Light on the Character and Fate of the South Pole-Aitken Basin Impact Melt Sheet

    NASA Astrophysics Data System (ADS)

    Jolliff, B. L.; Petro, N. E.; Shearer, C. K.; Pieters, C. M.; Head, J. W.

    2016-05-01

    Characterizing and accessing impact melt rocks of the South Pole-Aitken basin is of high priority for understanding the history of the Moon, the giant basin forming process, and establishing the chronology of giant impacts in the early solar system.

  2. Basin Analysis and Petroleum System Characterisation of Western Bredasdorp Basin, Southern Offshore of South Africa: Insights from a 3d Crust-Scale Basin Model - (Phase 1)

    NASA Astrophysics Data System (ADS)

    Sonibare, W. A.; Scheck-Wenderoth, M.; Sippel, J.; Mikeš, D.

    2012-04-01

    In recent years, construction of 3D geological models and their subsequent upscaling for reservoir simulation has become an important tool within the oil industry for managing hydrocarbon reservoirs and increasing recovery rate. Incorporating petroleum system elements (i.e. source, reservoir and trap) into these models is a relatively new concept that seems very promising to play/prospect risk assessment and reservoir characterisation alike. However, yet to be fully integrated into this multi-disciplinary modelling approach are the qualitative and quantitative impacts of crust-scale basin dynamics on the observed basin-fill architecture and geometries. The focus of this study i.e. Western Bredasdorp Basin constitutes the extreme western section of the larger Bredasdorp sub-basin, which is the westernmost depocentre of the four southern Africa offshore sub-basins (others being Pletmos, Gamtoos and Algoa). These basins, which appear to be initiated by volcanically influenced continental rifting and break-up related to passive margin evolution (during the Mid-Late Jurassic to latest Valanginian), remain previously unstudied for crust-scale basin margin evolution, and particularly in terms of relating deep crustal processes to depo-system reconstruction and petroleum system evolution. Seismic interpretation of 42 2D seismic-reflection profiles forms the basis for maps of 6 stratigraphic horizons which record the syn-rift to post-rift (i.e. early drift and late drift to present-day seafloor) successions. In addition to this established seismic markers, high quality seismic profiles have shown evidence for a pre-rift sequence (i.e. older than Late Jurassic >130 Ma). The first goal of this study is the construction of a 3D gravity-constrained, crust-scale basin model from integration of seismics, well data and cores. This basin model is constructed using GMS (in-house GFZ Geo-Modelling Software) while testing its consistency with the gravity field is performed using IGMAS

  3. Selected data for stream subbasins in the Watonwan River basin, south-central Minnesota

    USGS Publications Warehouse

    Lorenz, D.L.; Payne, G.A.

    1990-01-01

    This report presents selected data that describe the characteristics of stream basins upstream from selected points on streams in the Watonwan River basin. The points on the streams include outlets of subbasins of about five square miles, sewage treatment plant outlets, and U.S. Geological Survey streamflow-gaging stations in the basin.

  4. Selected data for stream subbasins in the Le Sueur River basin, south-central Minnesota

    USGS Publications Warehouse

    Lorenz, D.L.; Payne, G.A.

    1990-01-01

    This report presents selected data that describe the characteristics of stream basins upstream from selected points on streams in the Le Sueur River basin. The points on the streams include outlets of subbasins of about five square miles, sewage treatment plant outlets, and U.S. Geological Survey streamflow-gaging stations in the basin.

  5. Palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin, northern South China Sea.

    PubMed

    Li, Wenhao; Zhang, Zhihuan; Wang, Weiming; Lu, Shuangfang; Li, Youchuan; Fu, Ning

    2014-01-01

    The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter.

  6. Palaeoenvironment and Its Control on the Formation of Miocene Marine Source Rocks in the Qiongdongnan Basin, Northern South China Sea

    PubMed Central

    Li, Wenhao; Zhang, Zhihuan; Wang, Weiming; Lu, Shuangfang; Li, Youchuan; Fu, Ning

    2014-01-01

    The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter. PMID:25401132

  7. [IMPACT OF CASPIAN SEA LEVEL FLUCTUATIONS ON THE EPIZOOTIC ACTIVITY OF THE CASPIAN SANDY NATURAL PLAGUE FOCUS].

    PubMed

    Popov, N V; Udovikov, A I; Eroshenko, G A; Karavaeva, T B; Yakovlev, S A; Porshakov, A M; Zenkevich, E S; Kutyrev, V V

    2016-01-01

    There is evidence that in 1923-2014 the sharp aggravations of the epizootic situation of plague in the area of its Caspian sandy natural focus after long interepizootic periods are in time with the ups of the Caspian Sea in the extrema of 11-year solar cycles. There were cases of multiple manifestations of plague in the same areas in the epizootic cycles of 1946-1954, 1979-1996, 2001, and 2013-2014. The paper considers the possible role of amebae of the genus Acanthamoeba and nematodes, the representatives of the orders Rhabditida and Tylenchida in the microfocal pattern of plague manifestations. PMID:27029140

  8. [IMPACT OF CASPIAN SEA LEVEL FLUCTUATIONS ON THE EPIZOOTIC ACTIVITY OF THE CASPIAN SANDY NATURAL PLAGUE FOCUS].

    PubMed

    Popov, N V; Udovikov, A I; Eroshenko, G A; Karavaeva, T B; Yakovlev, S A; Porshakov, A M; Zenkevich, E S; Kutyrev, V V

    2016-01-01

    There is evidence that in 1923-2014 the sharp aggravations of the epizootic situation of plague in the area of its Caspian sandy natural focus after long interepizootic periods are in time with the ups of the Caspian Sea in the extrema of 11-year solar cycles. There were cases of multiple manifestations of plague in the same areas in the epizootic cycles of 1946-1954, 1979-1996, 2001, and 2013-2014. The paper considers the possible role of amebae of the genus Acanthamoeba and nematodes, the representatives of the orders Rhabditida and Tylenchida in the microfocal pattern of plague manifestations.

  9. The Permian Whitehill Formation (Karoo Basin, South Africa): deciphering the complexity and potential of an unconventional gas resource

    NASA Astrophysics Data System (ADS)

    Götz, Annette E.

    2014-05-01

    A key energy policy objective of the South African government is to diversify its energy mix from coal which constitutes 85% of the current mix. Gas will play a key role in the future South African economy with demand coming from electricity generation and gas-to-liquids projects. A study on world shale reserves conducted by the Energy Information Agency (EIA) in 2011 concluded that there could be as much as 485 Tcf recoverable reserves of shale gas in the South African Karoo Basin. However, the true extent and commercial viability is still unknown, due to the lack of exploration drilling and modern 3D seismic. The present study compiles existing data from literature review and new data from outcrop analogue studies on the Permian Whitehill Formation, the main target formation for future shale gas production, including thickness, depth, maturity, TOC, lithologies, sedimentary and organic facies, and dolerite occurrence to provide a first reference dataset for further investigations and resource estimates.

  10. Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

    PubMed

    Jiménez-Segura, L F; Galvis-Vergara, G; Cala-Cala, P; García-Alzate, C A; López-Casas, S; Ríos-Pulgarín, M I; Arango, G A; Mancera-Rodríguez, N J; Gutiérrez-Bonilla, F; Álvarez-León, R

    2016-07-01

    The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries.

  11. Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

    PubMed

    Jiménez-Segura, L F; Galvis-Vergara, G; Cala-Cala, P; García-Alzate, C A; López-Casas, S; Ríos-Pulgarín, M I; Arango, G A; Mancera-Rodríguez, N J; Gutiérrez-Bonilla, F; Álvarez-León, R

    2016-07-01

    The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries. PMID:27401480

  12. Sediment supply, tectonic subsidence, and basin-filling patterns across the southwestern South China Sea during Pliocene to recent time

    NASA Astrophysics Data System (ADS)

    Murray, Mychal R.; Dorobek, Steven L.

    Sediment flux to southwestern parts of the South China Sea (SCS) during late Cenozoic time reflects contributions from eastern Tibet, western Borneo, and smaller drainages of central Indochina, Vietnam, the Malay Peninsula, and western Indonesia, although little work has been done to evaluate the significance of each source. Regional seismic-reflection data and well logs from the southwestern SCS were used in this study to evaluate sediment flux and dispersal across the area. Regional seismic-stratigraphic patterns across the southwestern SCS, however, show that Pliocene to Recent sediment accumulation within individual basins was also strongly influenced by long-term changes in tectonic subsidence. More updip basins (e.g., Malay, Cuu Long, and West Natuna basins) became filled after Miocene inversion and an abrupt slowing of tectonic subsidence. Once they became filled, sediment could bypass the updip basins. In contrast, the eastern part of the Nam Con Son Basin (NCSB) has experienced much greater subsidence since early Miocene time and continues to receive sediment that bypasses the updip basins. The paleo-Mekong River and a second depositional system with probable headwaters on the Malay Peninsula began supplying large volumes of sediment to the NCSB during late Miocene and Pliocene time, respectively. Filling of updip basins allowed Pliocene to Recent fluvial and shelf facies to shift progressively eastward across the southwestern SCS. This study shows that Pliocene to Recent sediment dispersal and paleogeographic evolution of the southwestern SCS are as strongly influenced by subsidence patterns as they are by sediment supply from continental drainage systems.

  13. GRAIL Investigation of the Subsurface Structure of South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Ertel, A.; Nimmo, F.; Besserer, J.; Hurwitz, D. M.

    2014-12-01

    The GRAIL mission [1] has revealed a lunar crust that is globally less dense and presumably more porous [2] than anticipated. Measurements of the inferred (effective) density as a function of wavelength provide a way of probing the vertical density structure of the crust. Both the mean vertical density stratification [3] and spatial variations in the density structure [4] have been determined. Here we used an admittance approach [4] to investigate the subsurface structure of South Pole-Aikten (SPA) Basin. The SPA-forming impact was large enough to generate enormous quantities of melt [5,6] and a global ejecta layer [7]. The pre-existing crust was probably completely removed [8]; GRAIL data indicate a depth to the base of the crust (or other density interface) at a depth of about 13-20 km beneath the basin center [2]. Cooling and crystallization of the melt pool will have generated a distinct stratigraphy and density structure [6,5]. This predicted density structure can then be compared to that inferred from the GRAIL observations. We determined the effective density spectrum of SPA using a localized multitaper approach [4]. The effective density decreases from 2.7 g/cc at spherical harmonic degree l=250 to 2.6 g/cc at l=550, indicating an increase in density with depth. Two model predictions from [5] yield effective densities in the range 3.0-3.2 g/cc. The discrepancy between the predictions and the observations could be explained by 1) incorporations of large volumes of crustal material into the recrystallizing melt-sheet; or 2) ~20% fracture porosity extending to depths of 10 km or more. The latter possibility is more likely given SPA early formation and subsequent reprocessing and delivery of low-density material by impacts. [1] Zuber et al. 2013 [2] Wieczorek et al. 2013 [3] Han et al. 2013 [4] Besserer et al. 2014 [5] Hurwitz and Kring 2014 [6] Vaughan and Head 2013 [7] Petro and Pieters 2004 [8] Potter et al. 2012

  14. A geochemical investigation of crude oils from Eastern Pearl River Mouth Basin, South China Sea

    NASA Astrophysics Data System (ADS)

    Jiamo, Fu; Cunmin, Pei; Guoying, Sheng; Dehan, Liu; Sizhong, Chen

    A thorough petroleum exploration of the Pearl River Mouth Basin (PRMB), South China Sea, began in 1983. At present, several oilfields have been found in the PRMB, mainly distributed in Dongsha Massif, Huizhou and Xijiang Depressions as well as Huilu Lowhigh, and one of them has been developed recently. The crude oils found in the basin can be classified into two types. One is normal waxy type, and the other is cyclic type, which may be caused by minor biodegration and is restricted to the Liuhua District of Dongsha Massif. However, on the basis of geochemical characteristics, all the crude oils are thermally mature, indicating that they are derived from source rocks which have entered the main oil generation period but their maturity is not high enough to reach the overmature stage. Moreover, in the biomarker distribution, the oils also share many similarities. Almost all the oils contain abundant C 30 4-methylsteranes with 24-ethyl side chain, ubiquitous oleanane and lower concentration of gammacerane, and possess high ratios of Ni/V, pristane to phytane and C 30 hopane over total C 29 steranes as well as high paraffin wax and low sulphur content, indicating that they originated from terrestrial organic matter deposited in lacustrine and marsh coal-forming environments. However, some characteristics resemble Brazilian offshore oils of salinewater lacustrine environment. The oils found in the PRMB can also be classified into three main genetic types based on the relative values of pristane over phytane ratio, C 29 sterane preference and the composition of the carbon isotope. Type I oils occurred in the Huizhou and the Xijiang Depressions and their adjacent Dongsha Massif. It has higher ratios of pristane to phytane (1.80-5.54 and 3.21 on the average scale) and heavier carbon isotopic composition, indicating that their source rocks contain much more abundant terrestrial higher plant input. Type II, encountered in Huilu Lowhigh and its bounding area of Dongsha Massif

  15. Variability of mineral dust deposition in the western Mediterranean basin and south-east of France

    NASA Astrophysics Data System (ADS)

    Vincent, Julie; Laurent, Benoit; Losno, Rémi; Bon Nguyen, Elisabeth; Roullet, Pierre; Sauvage, Stéphane; Chevaillier, Servanne; Coddeville, Patrice; Ouboulmane, Noura; di Sarra, Alcide Giorgio; Tovar-Sánchez, Antonio; Sferlazzo, Damiano; Massanet, Ana; Triquet, Sylvain; Morales Baquero, Rafael; Fornier, Michel; Coursier, Cyril; Desboeufs, Karine; Dulac, François; Bergametti, Gilles

    2016-07-01

    Previous studies have provided some insight into the Saharan dust deposition at a few specific locations from observations over long time periods or intensive field campaigns. However, no assessment of the dust deposition temporal variability in connection with its regional spatial distribution has been achieved so far from network observations over more than 1 year. To investigate dust deposition dynamics at the regional scale, five automatic deposition collectors named CARAGA (Collecteur Automatique de Retombées Atmosphériques insolubles à Grande Autonomie in French) have been deployed in the western Mediterranean region during 1 to 3 years depending on the station. The sites include, from south to north, Lampedusa, Majorca, Corsica, Frioul and Le Casset (southern French Alps). Deposition measurements are performed on a common weekly period at the five sites. The mean dust deposition fluxes are higher close to the northern African coasts and decrease following a south-north gradient, with values from 7.4 g m-2 year-1 in Lampedusa (35°31' N, 12°37' E) to 1 g m-2 year-1 in Le Casset (44°59' N, 6°28' E). The maximum deposition flux recorded is of 3.2 g m-2 wk-1 in Majorca with only two other events showing more than 1 g m-2 wk-1 in Lampedusa, and a maximum of 0.5 g m-2 wk-1 in Corsica. The maximum value of 2.1 g m-2 year-1 observed in Corsica in 2013 is much lower than existing records in the area over the 3 previous decades (11-14 g m-2 year-1). From the 537 available samples, 98 major Saharan dust deposition events have been identified in the records between 2011 and 2013. Complementary observations provided by both satellite and air mass trajectories are used to identify the dust provenance areas and the transport pathways from the Sahara to the stations for the studied period. Despite the large size of African dust plumes detected by satellites, more than 80 % of the major dust deposition events are recorded at only one station, suggesting that the dust

  16. The potential of pesticides to contaminate the groundwater resources of the Axios river basin. Part II. Monitoring study in the south part of the basin.

    PubMed

    Papadopoulou-Mourkidou, E; Karpouzas, D G; Patsias, J; Kotopoulou, A; Milothridou, A; Kintzikoglou, K; Vlachou, P

    2004-04-01

    A monitoring study was conducted during 1992-1994 in the south part of the Axios river basin, which constitutes one of the main rice-cultivated basins of Greece. The potential of pesticides to contaminate groundwater resources was assessed under realistic agricultural conditions using suction lysimeters. Pesticide residues were also measured in local drainage canals, the phreatic horizon and Axios river. Carbofuran, atrazine, alachlor, prometryne and propanil were regularly detected at concentrations exceeding 1 microg/l in the soil water of deeper soil layers and in the phreatic horizon of the fields. Residues of those pesticides were measured in the soil water and the phreatic horizon of all the studied fields even though they had only been applied in certain fields. This almost uniform distribution of pesticide residues across the whole of the studied area was attributed to rice cultivation. Soil water and its pesticidal content was horizontally transported from saturated soil conditions beneath rice paddies to adjacent corn or cotton-cultivated fields with lower soil moisture contents. The presence of high pesticide concentrations in the water of the Axios river, which was used for the irrigation of the studied area, had probably contributed to the generalized pesticide contamination of the soil water in the studied area. These results suggest that there is a high risk for groundwater contamination in the basin.

  17. Macrophytobenthos of the Caspian Sea: Diversity, distribution, and productivity

    NASA Astrophysics Data System (ADS)

    Stepanian, O. V.

    2016-05-01

    In the Russian sector of the northern and middle Caspian Sea, 36 species of macroalgae have been identified. The green and red algae from the mesosaprobic group are dominant. An increase in the number of green algae species is revealed. The distribution of macroalgae is inhomogeneous. It is confined to the solid substrate and epiphyton. The biomass of seaweeds reaches 1.5 kg/m2. Climate change has little influence on the appearance of new species in the northern Caspian Sea, but new invaders can appear in the Middle and Southern Caspian. The distribution of aquatic and coastal hygrophytic vegetation shows considerable spatial dynamics due to fluctuations in the level and salinity of the Caspian Sea. The biomass of aquatic vegetation varies in a wide range from 0.5 to 10.0 kg/m2. Spatially detailed mathematical models adequately reflect the changes in key species of aquatic plants in space and time. It is shown that expansion of the zone of the seagrass Zostera noltii to shallow water areas is occurring at present, as well as shrinkage of the range of the dominant littoral aquatic plant Phragmites australis.

  18. Hydrocarbon-mediated gold and uranium concentration in the Witwatersrand Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Fuchs, Sebastian; Williams-Jones, Anthony; Schumann, Dirk; Couillard, Martin; Murray, Andrew

    2016-04-01

    The Witwatersrand deposits in South Africa represent the largest repository of gold in the World and a major resource of uranium. The genesis of the gold and uranium ores in the quartz-pebble conglomerates (reefs), however, is still a matter of considerable discussion. Opinion has been divided over whether they represent paleo-placers that have been partly remobilised by hydrothermal fluids or if the mineralisation is entirely hydrothermal in origin. In addition, recently published models have proposed a syngenetic origin for the gold involving bacterially-mediated precipitation from meteoric water and shallow seawater. An important feature of the gold and uranium mineralisation in the reefs is the strong spatial association with organic matter. In some reefs, up to 70% of the gold and almost the entire uranium resource is spatially associated with pyrobitumen seams, suggesting a genetic relationship of the gold-uranium mineralisation with hydrocarbons. Here we report results of a study of the Carbon Leader Reef, using high-resolution scanning and transmission electron microscopy (SEM / TEM) and LA-ICP-MS that provide new insights into the role of hydrocarbons in the concentration of the gold and uranium. A detailed examination revealed gold monocrystals containing numerous rounded or elliptical inclusions filled with pyrobitumen. We interpret these inclusions to record the crystallisation of the gold around droplets of a hydrocarbon liquid that migrated through the Witwatersrand basin, and was converted to pyrobitumen by being heated. We propose that the gold was transported in a hydrothermal fluid as a bisulphide complex and that this fluid mixed with the hydrocarbon liquid to form a water-oil emulsion. The interaction between the two fluids caused a sharp reduction in fO2 at the water-oil interface, which destabilised the gold-bisulphide complexes, causing gold monocrystals to precipitate around the oil droplets. In contrast to the gold, uraninite, the principal

  19. Air pollution source/receptor relationships in South Coast Air Basin, CA

    SciTech Connect

    Gao, N.

    1993-12-31

    This research project includes the application of some existing receptor models to study the air pollution source/receptor relationships in the South Coast Air Basin of southern California, the development of a new receptor model and the testing and the modifications of some existing models. These existing receptor models used include principal component factor analysis, potential source contribution function analysis, Kohonen`s neural network combined with Prim`s minimal spanning tree, and direct trilinear decomposition followed by a matrix reconstruction. The ambient concentration measurements used in this study are a subset of the data collected during the 1987 field exercise of Southern California Air Quality Study. It consists of a number of gaseous and particulate pollutants analyzed from samples collected by SCAQS samplers at eight sampling sites. Based on the information of emission inventories, meterology and ambient concentrations this receptor modeling study has revealed mechanisms that influence the air quality in SoCAB. Some of the mechanisms affecting the air quality in SoCAB that were revealed during this study include the following aspects. The SO{sub 2} collected at sampling sites is mainly contributed by refineries in the coastal area and the ships equipped with oil-fired boilers off shore. Combustion of fossil fuel by automobiles dominates the emission of NO{sub x} that is subsequently transformed and collected at sampling sites. Electric power plants also contribute HNO{sub 3} to the sampling sites. A large feedlot in the eastern region of SoCAB has been identified as the major source of NH{sub 3}. Possible contributions from other industrial sources such as smelters and incenerators were also revealed. The results of this study also suggest the possibility of DMS (dimethylsuflide) and NH{sub 3} emissions from off-shore sediments that have been contaminated by waste sludge disposal.

  20. Geochemistry of the early Cretaceous Gunbuk-Jindong granitoids in the Gyeongsang basin, South Korea

    NASA Astrophysics Data System (ADS)

    Wee, Soo-Meen

    2014-05-01

    The Gunbuk-Jindong granitoids are located in the southwestern part of the Gyeongsang Basin in South Korea. The granitoids consists of gabbro, quartz diorite, granodiorite and granite that are intruded into Cretaceous sedimentary rocks of the Jindong formation. Gunbuk granitoids exhibit relatively high Al2O3,MgO, Cr and Sr contents, high Sr/Y and La/Yb ratios, but low Y and Yb contents, similar to adakites produced by slab melting associated with ridge subduction. In contrast, the Jindong granitoids have low Sr and high Y contents and are typical of calc-alkaline I-type granitoids. The Rb-Sr isotopic age of 97.0±8.4Ma with an initial Sr ratio of 0.7046 recommend that the magma has mantle signature and intruded during Early Cretaceous. The geochemical and tectonic features reveal that adakite-like signatures of the Gunbuk granitoids were generated by the interaction of slab-derived adakitic melts(caused by the thermal effect of ridge subduction) and mantle peridotite. The Gunbuk granitoids have similar geochemical characteristics, paleotectonic environments and intrusion ages to those of the Shiraishino granodiorites of Kyushu Island and the Tamba granitoids of San'yo belt located on southwestern Japanese arc. Chondrite normalized REE patterns show generally enriched LREEs and slight negative to flat Eu anomalies. On the ANK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite(VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of the Izanagi plate beneath the northeastern part of the Eurasian plate.

  1. Geochemistry of the Early Cretaceous Gunbuk-Jindong granitoids in the Gyeongsang basin, South Korea

    NASA Astrophysics Data System (ADS)

    Wee, S. M.

    2013-12-01

    The Gunbuk-Jindong granitoids are located in the southwestern part of the Gyeongsang Basin in South Korea. The granitoids consists of gabbro, quartz diorite, granodiorite and granite that are intruded into Cretaceous sedimentary rocks of the Jindong formation. Gunbuk granitoids exhibit relatively high Al2O3, MgO, Cr and Sr contents, high Sr/Y and La/Yb ratios, but low Y and Yb contents, similar to adakites produced by slab melting associated with ridge subduction. In contrast, the Jindong granitoids have low Sr and high Y contents and are typical of calc-alkaline I-type granitoids. The Rb-Sr isotopic age of 97.0×8.4Ma with an initial Sr ratio of 0.7046 recommend that the magma has mantle signature and intruded during Early Cretaceous. The geochemical and tectonic features reveal that adakite-like signatures of the Gunbuk granitoids were generated by the interaction of slab-derived adakitic melts(caused by the thermal effect of ridge subduction) and mantle peridotite. The Gunbuk granitoids have similar geochemical characteristics, paleotectonic environments and intrusion ages to those of the Shiraishino granodiorites of Kyushu Island and the Tamba granitoids of San'yo belt located on southwestern Japanese arc. Chondrite normalized REE patterns show generally enriched LREEs and slight negative to flat Eu anomalies. On the ANK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite(VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of the Izanagi plate beneath the northeastern part of the Eurasian plate.

  2. Groundwater potential zoning of a peri-urban wetland of south Bengal Basin, India.

    PubMed

    Sahu, Paulami; Sikdar, Pradip K

    2011-03-01

    Demand for groundwater for drinking, agricultural, and industrial purposes has increased due to rapid increase in population. Therefore, it is imperative to assess the groundwater potential of different areas, especially in a fragile wetland ecosystem to select appropriate sites for developing well fields to minimize adverse environmental impacts of groundwater development. This study considers East Calcutta Wetlands (ECW)--a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems developed by local people through ages, using wastewater of the city. The subsurface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades, and sand mixed with occasional gravels and thin intercalations of silty clay. Groundwater occurs mostly under confined condition except in those places where the top aquitard has been obliterated due to scouring action of past channels. The groundwater in the study area is being over-extracted at the rate of 65 × 10(3) m(3)/day. Overlay analysis in Geographic Information System platform using multiple criteria such as water quality index, hydraulic conductivity, groundwater velocity, and depth to piezometric surface reveals that in and around ECW, there are five groundwater potential zones. About 74% of the aquifer of this area shows very poor to medium groundwater potential. Management options such as minimization of groundwater abstraction by introducing the treated surface water supply system and the implementation of rainwater harvesting and artificial recharge in high-rise buildings and industries are suggested for different potential zones.

  3. Postbreeding resource selection by adult black-footed ferrets in the Conata Basin, South Dakota

    USGS Publications Warehouse

    Eads, D.A.; Millspaugh, J.J.; Biggins, D.E.; Livieri, T.M.; Jachowski, D.S.

    2011-01-01

    We investigated postbreeding resource selection by adult black-footed ferrets (Mustela nigripes) on a 452-ha black-tailed prairie dog (Cynomys ludovicianus) colony in the Conata Basin of South Dakota during 20072008. We used resource selection functions (RSFs) to evaluate relationships between numbers of ferret locations and numbers of prairie dog burrow openings (total or active), distances to colony edges, and connectivity of patches of burrow openings. In both years ferrets selected areas near edges of the prairie dog colony where active burrow openings were abundant. In the interior of the colony ferrets selected areas with low abundance of active burrow openings. At times, prairie dog productivity (i.e., pup abundance) might be greatest at colony edges often characterized by grasses; ferrets are likely to select areas where refuge and vulnerable prey are abundant. Ferrets could have used interior areas with few active burrow openings as corridors between edge areas with many active burrow openings. Also, in areas with few active burrow openings ferrets spend more time aboveground during movements and, thus, are likely to be more easily detected. These results complement previous studies demonstrating importance of refuge and prey in fine-scale resource selection by ferrets and provide insight into factors that might influence edge effects on ferret space use. Conservation and restoration of colonies with areas with high densities of burrow openings and prairie dogs, and corridors between such areas, are needed for continued recovery of the black-footed ferret. RSFs could complement coarse-scale habitat evaluations by providing finer-scale assessments of habitat for the black-footed ferret. ?? 2011 American Society of Mammalogists.

  4. Groundwater potential zoning of a peri-urban wetland of south Bengal Basin, India.

    PubMed

    Sahu, Paulami; Sikdar, Pradip K

    2011-03-01

    Demand for groundwater for drinking, agricultural, and industrial purposes has increased due to rapid increase in population. Therefore, it is imperative to assess the groundwater potential of different areas, especially in a fragile wetland ecosystem to select appropriate sites for developing well fields to minimize adverse environmental impacts of groundwater development. This study considers East Calcutta Wetlands (ECW)--a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems developed by local people through ages, using wastewater of the city. The subsurface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades, and sand mixed with occasional gravels and thin intercalations of silty clay. Groundwater occurs mostly under confined condition except in those places where the top aquitard has been obliterated due to scouring action of past channels. The groundwater in the study area is being over-extracted at the rate of 65 × 10(3) m(3)/day. Overlay analysis in Geographic Information System platform using multiple criteria such as water quality index, hydraulic conductivity, groundwater velocity, and depth to piezometric surface reveals that in and around ECW, there are five groundwater potential zones. About 74% of the aquifer of this area shows very poor to medium groundwater potential. Management options such as minimization of groundwater abstraction by introducing the treated surface water supply system and the implementation of rainwater harvesting and artificial recharge in high-rise buildings and industries are suggested for different potential zones. PMID:20437269

  5. Light Plains in the South-Pole Aitken Basin: Surface Ages and Mineralogical Composition

    NASA Astrophysics Data System (ADS)

    Thiessen, F.; Hiesinger, H.; van der Bogert, C. H.; Pasckert, J. H.; Robinson, M. S.

    2012-04-01

    We studied light plains in the north-eastern South-Pole Aitken basin to investigate their origin, ages, and mineralogical composition. Light plains, also known as the Cayley Formation, occur on the near- and farside of the Moon. Due to their smooth texture, lower crater densities, and occurrence as crater fills, they were thought to be of volcanic origin [e.g., 1]. However, Apollo 16 samples of light plains deposits were in fact highly brecciated rocks [2]. Therefore, the Imbrium and Orientale impacts were thought to have formed light plains because they reshaped the surface thousands of kilometers from their impact sites. Subsequent studies revealed varying surface ages of light plains [e.g., 3] and different mineralogical compositions, which are in some cases more highland-like and in others more mare-like. Hence, an origin solely from the Imbrium and/or Orientale impacts is unlikely. Thus, the question whether light plains formed due to large impacts or regional cratering, or through endogenic processes remains open. We performed crater size-frequency measurements [e.g., 4] on Lunar Reconnaissance Orbiter Wide Angle Camera images and obtained absolute model ages between 3.43 and 3.81 Ga. We observed neither a distinctive peak of light plains ages nor clustering of similar ages in any specific regions of the studied area. Due to the fact that the derived ages vary as much as 380 Ma, an origin by a single event seems unlikely. Moreover, some ages even post-date the Imbrium and Orientale impacts, and thus an origin related to those impacts is not likely. Examination of multispectral data from Clementine [5] shows that the Ti abundances vary between 0.2 and 3 wt % and Fe abundances between 12.5 and 19 wt %. We observed a regional difference in distribution: light plains units within the Apollo basin have lower Fe and Ti values and are more highland-like, whereas light plains outside the Apollo basin show higher Fe and Ti values and are more mare-like. Furthermore, M

  6. Statistical summaries of water-quality data for selected streamflow-gaging stations in the Red River of the North basin, North Dakota, Minnesota, and South Dakota

    USGS Publications Warehouse

    Macek-Rowland, Kathleen M.; Dressler, Valerie M.

    2002-01-01

    The quantity and quality of current and future water resources in the Red River of the North Basin in North Dakota, Minnesota, and South Dakota are concerns of people who reside within the basin. Additional water resources are needed because of recent growth in population, industry, and agriculture. How the management of current and future water-resources will impact water quality within the basin is a critical issue. Water-quality data, particularly for surface-water sources, will help water-resources managers make decisions about current and future water resources in the Red River of the North Basin. Statistical summaries of water-quality data for 43 streamflow-gaging stations in the Red River of the North Basin in North Dakota, Minnesota, and South Dakota are presented in this report. Statistical summaries include sample size, maximum, minimum, mean, and values for the 95th, 75th, 50th, 25th, and 5th percentiles.

  7. Initial constraints on crustal structure across the Suwanee Suture and South Georgia Basin from the SUGAR seismic refraction experiment

    NASA Astrophysics Data System (ADS)

    Shillington, D. J.; Lizarralde, D.; Harder, S. H.

    2014-12-01

    Some of the most important unresolved questions in plate tectonics concern the formation and rupture of continents. How does the accretion of terranes contribute to the construction of continental lithosphere, and what processes enable continental lithosphere to rupture? The South Georgia Basin was at the center of the most recent sequence of continental collision and rifting events to shape eastern North America. It is the largest of the failed Mesozoic rift basins that formed during the breakup of Pangea. It straddles the Suwannee Suture, the only well-defined remnant of the Alleghenian suture that joined North America and Gondwana, forming Pangea. The South Georgia Basin also lies at the center of the Central Atlantic Magmatic Province (CAMP). Here we present initial results from the first phase of the SUwanee Suture and GA Rift basin (SUGAR) project, an active-source seismic refraction project to image the crustal structure across these features. During March 2014, we acquired data along a ~325-km-long, NW-SE oriented profile that crossed the Suwanne Suture and western part of South Georgia Basin, extending from north of Columbus, GA to northernmost Florida east of Jasper, FL. The profile was densely instrumented with single-channel RekTek 125A seismometers ("Texans") spaced at ~250 m and deployed along state and country roads, yielding a total of 1193 seismometers along the profile. Thirty-three students and young scientists were involved in the deployment and recovery. The sources were 100 to 1800 lb shots spaced at ~20-50 km. The data are of exceptionally high quality. On nearly all shots, we observe arrivals out to the largest shot-receiver offsets. Within the basin, refractions through the sedimentary section with apparent velocities of ~3-4 km/s are observed to maximum offsets of 7 km. Crustal refractions are observed at a wide-range of offsets with apparent velocities increasing from ~5.5 km/s to as high as ~7.25 km/s. At offsets greater than 150-180 km

  8. Porosity and Permeability of Jurassic-Triassic Formations of the South Georgia Rift Basin: Potential Implications for CO2 Storage

    NASA Astrophysics Data System (ADS)

    Akintunde, O. M.; Knapp, C. C.; Knapp, J. H.; Prasad, M.; Olsen, P. E.

    2011-12-01

    Porosity and permeability are critical for evaluating reservoir injectivity and seal integrity for subsurface CO2 storage. Both properties are needed to determine the effective CO2 storage capacity. In addition, the ability to model and understand the physical interactions of the CO2 reservoir systems under in situ conditions is dependent on the reservoir porosity. We present results of rock physics evaluation of the porosity and permeability of the buried Jurassic-Triassic formations of the South Georgia Rift (SGR) basin using existing well and new experimental data. The SGR basin covers parts of South Carolina, Georgia, Alabama, and Florida and is buried beneath Cretaceous and younger Coastal Plain sediments. We focused our study on the South Carolina portion of the basin that has been identified in the Carbon Sequestration Atlas of United States and Canada as containing saline formations suitable for subsurface CO2 storage. Results of our rock physics analysis confirm the presence of porous reservoir units capped by low-porosity diabase sills. These potential reservoirs appear to have the capacity (pore volume and porosity) to store significant quantities of supercritical CO2. Our analysis further suggests that the SGR basin may contain distinct porosity-permeability regimes (geo-hydrologic systems) that are influenced by depositional environments. These regimes are: (1) high-porosity, low/medium permeability, as observed in the Norris Lightsey well with Triassic formation porosity of 20 - 32.5 percent and core-derived permeability of 1.5 - 8.9 mD, and (2) low-porosity, low-permeability, based on the average total porosity of 6.3 percent and permeability of 6.6 (E-5) - 1.6 (E-2) mD reported in the literature for the Dunbarton Triassic sediments. The Norris Lightsey sedimentary rocks are primarily lacustrine deposits and consist of fine-grained Triassic sandstone with interbedded layers of siltstone and mudstone, while the Dunbarton basin is dominated by fluvial

  9. Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of "de la Plata" River Basin (South America).

    PubMed

    Perbiche-Neves, Gilmar; Boxshall, Geoffrey Allan; Previattelli, Daniel; Nogueira, Marcos Gomes; da Rocha, Carlos Eduardo Falavigna

    2015-01-01

    An identification guide is presented for species of calanoid copepod family Diaptomidae from "de la Plata" River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region.

  10. Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of “de la Plata” River Basin (South America)

    PubMed Central

    Perbiche-Neves, Gilmar; Boxshall, Geoffrey Allan; Previattelli, Daniel; Nogueira, Marcos Gomes; da Rocha, Carlos Eduardo Falavigna

    2015-01-01

    Abstract An identification guide is presented for species of calanoid copepod family Diaptomidae from “de la Plata” River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region. PMID:25931959

  11. Integrated numerical modeling for basin-wide water management: The case of the Rattlesnake Creek basin in south-central Kansas

    NASA Astrophysics Data System (ADS)

    Sophocleous, M. A.; Koelliker, J. K.; Govindaraju, R. S.; Birdie, T.; Ramireddygari, S. R.; Perkins, S. P.

    1999-01-01

    The objective of this article is to develop and implement a comprehensive computer model that is capable of simulating the surface-water, ground-water, and stream-aquifer interactions on a continuous basis for the Rattlesnake Creek basin in south-central Kansas. The model is to be used as a tool for evaluating long-term water-management strategies. The agriculturally-based watershed model SWAT and the ground-water model MODFLOW with stream-aquifer interaction routines, suitably modified, were linked into a comprehensive basin model known as SWATMOD. The hydrologic response unit concept was implemented to overcome the quasi-lumped nature of SWAT and represent the heterogeneity within each subbasin of the basin model. A graphical user-interface and a decision support system were also developed to evaluate scenarios involving manipulation of water rights and agricultural land uses on stream-aquifer system response. An extensive sensitivity analysis on model parameters was conducted, and model limitations and parameter uncertainties were emphasized. A combination of trial-and-error and inverse modeling techniques were employed to calibrate the model against multiple calibration targets of measured ground-water levels, streamflows, and reported irrigation amounts. The split-sample technique was employed for corroborating the calibrated model. The model was run for a 40 y historical simulation period, and a 40 y prediction period. A number of hypothetical management scenarios involving reductions and variations in withdrawal rates and patterns were simulated. The SWATMOD model was developed as a hydrologically rational low-flow model for analyzing, in a user-friendly manner, the conditions in the basin when there is a shortage of water.

  12. Integrated numerical modeling for basin-wide water management: The case of the Rattlesnake Creek basin in south-central Kansas

    USGS Publications Warehouse

    Sophocleous, M.A.; Koelliker, J.K.; Govindaraju, R.S.; Birdie, T.; Ramireddygari, S.R.; Perkins, S.P.

    1999-01-01

    The objective of this article is to develop and implement a comprehensive computer model that is capable of simulating the surface-water, ground-water, and stream-aquifer interactions on a continuous basis for the Rattlesnake Creek basin in south-central Kansas. The model is to be used as a tool for evaluating long-term water-management strategies. The agriculturally-based watershed model SWAT and the ground-water model MODFLOW with stream-aquifer interaction routines, suitably modified, were linked into a comprehensive basin model known as SWATMOD. The hydrologic response unit concept was implemented to overcome the quasi-lumped nature of SWAT and represent the heterogeneity within each subbasin of the basin model. A graphical user-interface and a decision support system were also developed to evaluate scenarios involving manipulation of water fights and agricultural land uses on stream-aquifer system response. An extensive sensitivity analysis on model parameters was conducted, and model limitations and parameter uncertainties were emphasized. A combination of trial-and-error and inverse modeling techniques were employed to calibrate the model against multiple calibration targets of measured ground-water levels, streamflows, and reported irrigation amounts. The split-sample technique was employed for corroborating the calibrated model. The model was run for a 40 y historical simulation period, and a 40 y prediction period. A number of hypothetical management scenarios involving reductions and variations in withdrawal rates and patterns were simulated. The SWATMOD model was developed as a hydrologically rational low-flow model for analyzing, in a user-friendly manner, the conditions in the basin when there is a shortage of water.

  13. Influence of Extrinsic and Intrinsic Controls on the Architecture of Basin Floor to Shelf Edge Stratigraphy, Laingsburg Karoo Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Hodgson, D. M.; Flint, S. S.; Brunt, R.; van der Merwe, W.; Prelat, A.; Figueiredo, J.

    2009-12-01

    The initial filling of a high latitude proto-foreland basin during an icehouse climate is recorded in a well-exposed 1.3 km thick basin-floor to shelf-edge succession of late Permian siliciclastic deposits in the Laingsburg depocentre of the SW Karoo basin, South Africa,. Uniformly fine-grained sandstones were derived from far-field granitic sources (Patagonia?), although the coeval staging and delivery systems (fluvial and shelfal) are not preserved. Initial mud-prone basin floor turbidites of the Vischkuil Formation contain three regionally developed zones of soft sediment deformation related to emplacement of major debris-flows that mark the initiation of a major sand delivery system. The overlying 300 m thick sand-prone basin floor fan system (Fan A) and 150 m thick base-of-slope channel/levee system (Unit B) are divisible into four composite sequences that show long term forward stepping, aggradation and backstepping stacking patterns, followed by basinwide pelagic mud deposition. The overlying 500 m thick mud-dominated submarine slope succession is characterized by 60 - 120 m thick sand-prone to heterolithic packages that show abrupt lateral and down-dip changes in thickness and lithofacies, which are separated by extensive 30 - 70 m thick claystone packages. On the largest scale the slope stratigraphy is defined by two major cycles, each comprising three composite sequences of repeating architectural style. Each composite sequence comprises three sequences. The lower cycle comprises lithostratigraphic Units B/C, C and D while the upper cycle includes Units E/F, E and F. In each case a sandy basal sequence is dominated by intraslope lobe deposits (Units B/C and E/F). The second composite sequence in each cycle (Unit C and Unit E) is characterized by slope channel-levee complexes that feed lobes down dip. The uppermost composite sequence in each cycle (Units D and F) comprises deeply entrenched slope valley/canyon systems. Although complicated in detail, the

  14. Mesozoic hydrocarbon source rock studies of north Tarim, south Junggar, and Turpan basins, Xinjiang Uygur autonomous region, northwestern China

    SciTech Connect

    Hendrix, M.S.; Xiao, Z.; Liang, Y.; Graham, S.A.; Carroll, A.R.; Chu, J.; McKnight, C.

    1989-03-01

    Ongoing outcrop and accompanying pyrolysis studies of Mesozoic strata of the north Tarim, south Junggar, and Turpan retroarc foreland basins, northwestern China, have demonstrated the existence of potential oil-prone and gas-prone petroleum source rocks. Lithologies include Jurassic coals from all three basins and Triassic coals from Tarim. Jurassic coals collected from the Mesozoic depocenters of the Junggar and Tarim basins are oil prone, yielding S/sub 2//S/sub 2+3/ values that range from 0.80 to 0.99 and average 0.96, hydrogen index (HI) values that range from 117.9 to 213.4 and average 150.8, and oxygen index (OI) values that range from 1.1 to 31.6 and average 7.67. In contrast, Triassic coals of Tarim and Jurassic coals of Turpan contain more conventional type III gas-prone kerogens and yield S/sub 2//S/sub 2+3/ values ranging from 0.04 to 0.52 and averaging 0.22, HI values ranging from 3.2 to 130.2 with a mean of 33.6, and OI values ranging from 30.9 to 223.7 and averaging 115.9. Coals of all three basins are slightly immature to mature with respect to oil generation, as indicated by T/sub max/ values ranging from 425/degrees/ to 449/degrees/C (average = 343/degrees/C) and vitrinite reflectance values ranging from 0.51 to 0.64 (average = 0.57). Thus, given the widespread abundance and significant thicknesses of Mesozoic and especially Jurassic coals in all three basins, it is very likely that Mesozoic contributions to Xinjiang's oil and gas reserves are significant. This is particularly important in the north Tarim basin, where recent Chinese oil and gas discoveries have been made and the existence of significant pre-Mesozoic source beds remains unproven.

  15. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    NASA Astrophysics Data System (ADS)

    Mattingly, Kyle S.; Mote, Thomas L.

    2016-03-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  16. sRecovery Act: Geologic Characterization of the South Georgia Rift Basin for Source Proximal CO2 Storage

    SciTech Connect

    Waddell, Michael

    2014-09-30

    This study focuses on evaluating the feasibility and suitability of using the Jurassic/Triassic (J/TR) sediments of the South Georgia Rift basin (SGR) for CO2 storage in southern South Carolina and southern Georgia The SGR basin in South Carolina (SC), prior to this project, was one of the least understood rift basin along the east coast of the U.S. In the SC part of the basin there was only one well (Norris Lightsey #1) the penetrated into J/TR. Because of the scarcity of data, a scaled approach used to evaluate the feasibility of storing CO2 in the SGR basin. In the SGR basin, 240 km (~149 mi) of 2-D seismic and 2.6 km2 3-D (1 mi2) seismic data was collected, process, and interpreted in SC. In southern Georgia 81.3 km (~50.5 mi) consisting of two 2-D seismic lines were acquired, process, and interpreted. Seismic analysis revealed that the SGR basin in SC has had a very complex structural history resulting the J/TR section being highly faulted. The seismic data is southern Georgia suggest SGR basin has not gone through a complex structural history as the study area in SC. The project drilled one characterization borehole (Rizer # 1) in SC. The Rizer #1 was drilled but due to geologic problems, the project team was only able to drill to 1890 meters (6200 feet) instead of the proposed final depth 2744 meters (9002 feet). The drilling goals outlined in the original scope of work were not met. The project was only able to obtain 18 meters (59 feet) of conventional core and 106 rotary sidewall cores. All the conventional core and sidewall cores were in sandstone. We were unable to core any potential igneous caprock. Petrographic analysis of the conventional core and sidewall cores determined that the average porosity of the sedimentary material was 3.4% and the average permeability was 0.065 millidarcy. Compaction and diagenetic studies of the samples determined there would not be any porosity or permeability at depth in SC. In Georgia there appears to be porosity in

  17. Study plan for the regional aquifer-system analysis of alluvial basins in south-central Arizona and adjacent states

    USGS Publications Warehouse

    Anderson, T.W.

    1980-01-01

    The U.S. Geological Survey has started a 4-year study of the alluvial basins in south-central Arizona and parts of California , Nevada, and New Mexico to describe the hydrologic setting, available groundwater resources, and effects of historical development on the groundwater system. To aid in the study, mathematical models of selected basins will be developed for appraising local and regional flow systems. Major components necessary to accomplish the study objectives include the accumulation of existing data on groundwater quantity and quality, entering the data into a computer file, identification of data deficiencies, and development of a program to remedy the deficiencies by collection of additional data. The approach to the study will be to develop and calibrate models of selected basins for which sufficient data exist and to develop interpretation-transfer techniques whereby general predevelopment and postdevelopment conceptual models of the hydrologic system in other basins may be synthesized. The end result of the project will be a better definition of the hydrologic parameters and a better understanding of the workings of the hydrologic system. The models can be used to study the effects of management alternatives and water-resources development on the system. (USGS)

  18. Geothermal energy from the Main Karoo Basin (South Africa): An outcrop analogue study of Permian sandstone reservoir formations

    NASA Astrophysics Data System (ADS)

    Campbell, Stuart A.; Lenhardt, Nils; Dippenaar, Matthys A.; Götz, Annette E.

    2016-04-01

    The geothermal potential of the South African Main Karoo Basin has not been addressed in the past, although thick siliciclastic successions in geothermal prone depths are promising target reservoir formations. A first assessment of the geothermal potential of the Karoo Basin is based on petro- and thermophysical data gained from an outcrop analogue study of Permian sandstones in the Eastern Cape Province, and evaluation of groundwater temperature and heat flow values from literature. A volumetric approach of the sandstones' reservoir potential leads to a first estimation of 2240 TWh (8.0 EJ) of power generation within the central and southern part of the basin. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Karoo for future geothermal resource exploration, development and production. The mainly low permeability lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas auto-convective thermal water circulation might be expected and direct heat use becomes reasonable. The data presented here serve to identify exploration areas and are valuable attributes for reservoir modeling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization.

  19. Rock-Eval pyrolysis and vitrinite reflectance results from the Sheep Creek 1 well, Susitna basin, south-central Alaska

    USGS Publications Warehouse

    Stanley, Richard G.; Lillis, Paul G.; Pawlewicz, Mark J.; Haeussler, Peter J.

    2014-01-01

    We used Rock-Eval pyrolysis and vitrinite reflectance to examine the petroleum source potential of rock samples from the Sheep Creek 1 well in the Susitna basin of south-central Alaska. The results show that Miocene nonmarine coal, carbonaceous shale, and mudstone are potential sources of hydrocarbons and are thermally immature with respect to the oil window. In the samples that we studied, coals are more organic-rich and more oil-prone than carbonaceous shales and silty mudstones, which appear to be potential sources of natural gas. Lithologically similar rocks may be present in the deeper parts of the subsurface Susitna basin located west of the Sheep Creek 1 well, where they may have been buried deeply enough to generate oil and (or) gas. The Susitna basin is sparsely drilled and mostly unexplored, and no commercial production of hydrocarbons has been obtained. However, the existence of potential source rocks of oil and gas, as shown by our Rock-Eval results, suggests that undiscovered petroleum accumulations may be present in the Susitna basin.

  20. Seismic expression of depositional systems tracts and application to hydrocarbon exploration in Bredasdorp basin, offshore South Africa

    SciTech Connect

    Beamish, G.W.J.

    1989-03-01

    Postrift Cretaceous sequences of Bredasdorp basin, offshore South Africa, were rigorously analyzed using the unified application of the latest seismic-stratigraphic, sequence-stratigraphic, and depositional systems concepts. Using 101 seismic profiles totaling 5600 km, the authors identified ten cyclic depositional sequences bounded by nine type 1 and two type 2 unconformities. Component depositional systems tracts exhibit a distinct seismic expression and can be delineated using truncation and lap-out relationships. Lowstand systems tracts developed on type 1 unconformities, which resulted from relative sea level fall below the shelf edge. In a terrigenous clastic basin such as Bredasdorp, these tracts are interpreted as being composed of basin-floor turbidite fans, channels, and/or sheets. These features formed contemporaneously with the erosion of incised valleys and submarine canyons, followed by channelized slope fans and deltaic/coastal lowstand wedges that prograded during a relative sea level rise. Subsequent flooding of the shelf as relative sea level rise accelerated resulted in poorly defined transgressive systems tracts. With the relative sea level at a highstand, extensively developed deltaic/coastal systems prograded basinward exhibiting well-defined clinoforms. The major hydrocarbon plays in the lowstand tracts occur as mounded basin-floor turbidite fans, channel fills, and draped sheets and are found in the updip pinch-out of deltaic/coastal sandstones.

  1. Seismic Reflection Moho Structure of Southwest Sub-basin of South China Sea and Implications for Continental Break-up and Seafloor Spreading Mechanisms

    NASA Astrophysics Data System (ADS)

    Zhang, Jinchang; Yan, Pin

    2016-04-01

    Across-basin Moho structure of South China Sea is important for understanding crustal evolution mechanisms of both continental break-up and seafloor spreading processes. Among all the basins in South China Sea, southwest sub-basin opened up the latest and has the closest continental margins, making it the best to study the across-basin structure. Multichannel seismic (MCS) reflection data of NH973-1 line that crosses southwest sub-basin in NW-SE direction were reprocessed in order to image Moho structure. In MCS data Moho reflectors are observed in places, which were not revealed in prior researches. The Moho generally shows symmetric structure on the both sides of the central rift valley. Beneath the oceanic crust in the middle of the basin, the Moho is ~2 seconds depth in two-way travel time (TWTT), which corresponds to ~7 km depth, showing normal oceanic crustal accretion during the seafloor spreading process. When getting close to continent-ocean boundary (COB), the Moho becomes shallow to <1 second depth in TWTT (~3.5 km), implying strongly crustal thinning. At south COB, the Moho depth almost reaches zero, which implies nearly no crust exists and probably the upper mantle could be exhumed. In addition, two low-angle, deep-penetrating normal faults are observed at south COB. The faults cut across the Moho into the upper mantle, which may have been caused by lithospheric hyper-stretching at COB during the continental break-up process.

  2. Reprint of "Magmatism, structure and age of Dove Basin (Antarctica): A key to understanding South Scotia Arc development"

    NASA Astrophysics Data System (ADS)

    Galindo-Zaldívar, Jesús; Puga, Encarnación; Bohoyo, Fernando; González, Francisco Javier; Maldonado, Andrés; Martos, Yasmina M.; Pérez, Lara F.; Ruano, Patricia; Schreider, Anatoly A.; Somoza, Luis; Suriñach, Emma; Antonio, Díaz de Federico

    2014-12-01

    Dove Basin is situated in the south-central Scotia Sea, between Pirie and Bruce banks, and was formed during the development of the Scotia Arc. The basin has a roughly sigmoidal shape, with a prominent NNE-SSW elongated ridge located in its central part, the Dove Ridge, which is considered as an extinct spreading axis. A NE-SW elongated tectonic high, the Dove Seamount, is located in the north-eastern region of the basin, bounded by a normal fault dipping to the southeast. Dredged rocks and geophysical data were collected during the SCAN2004 and SCAN2008 cruises. Dredged samples were recovered from three positive features in the center of the basin, two from Dove Ridge, and one from Dove Seamount. Igneous rocks along the Dove Ridge are mainly tholeiitic basalts, derived from asthenospheric upper mantle within an extensional supra-subduction back-arc tectonic setting, which evolved over time from back-arc basin basalts (BABB) toward Mid Oceanic Ridge Basalts (MORBs). Altered olivine-bearing fine- and medium-grained basaltic rocks were also dredged from Dove Ridge and the seamount, together with minor oceanic island arc basalts and basaltic andesites. The mantle source was affected, up to early Miocene times, by a subducted oceanic slab related to an arc to the east, with Dove Basin forming in a back-arc position. Minor alkaline oceanic island basalts dredged at the seamount might represent a final extensional stage, genetically related with the dying Dove Ridge volcanism or, less probably, to a later, late Miocene-Pliocene extensional stage, producing incipient volcanism deriving from a deeper mantle source. 40Ar/39Ar dating of MORB samples dredged from the Dove Ridge provided ages of 20.4 ± 2.6 to 22.8 ± 3.1 Ma. These outcrops were later coated by Fe-Mn crusts with Co-Chronometer ages ranging from at least 12.6 Ma and probably up to 18 Ma. Analysis of magnetic anomaly profiles shows the best fit in the central profile, corresponding to chrons C6B (21.7 Ma) to C7

  3. Stable isotope distribution in continental Maastrichtian vertebrates from the Haţeg Basin, South Carpathians

    NASA Astrophysics Data System (ADS)

    Bojar, Ana-Voica; Csiki, Zoltan; Grigorescu, Dan

    2010-05-01

    The oxygen isotopic compositions of biogenic apatite from crocodiles, turtles and dinosaurs, and their relationship to climate and physiology have been evidenced by several studies (Barrick and Showers, 1995; Kolodny et al., 1996; Barrick et al., 1999; Fricke and Rogers, 2000; Stoskopf et al., 2001; Straight et al., 2004; Amiot et al., 2007). To date, few attempts have been made to correlate the enamel d13C to dietary resources of dinosaurs (Bocherens et al., 1988; Stanton Thomas and Carlson, 2004; Fricke and Pearson, 2008; Fricke, et al., 2008). One additional complication is that for dinosaurs, the d18O of enamel phosphate depends on both body water and variations in body temperature. Several studies addressed the issue of endothermy vs. ectothermy of fossil vertebrates by studying inter- and intra-bone and enamel isotopic variability (Barrick and Showers, 1994, 1995; Barrick et al., 1996; 1998; Fricke and Rogers, 2000). More recent investigations provided evidence for inter-tooth temporal variations and related them to seasonality and/or changes in physiology (Straight et al., 2004; Stanton Thomas and Carlson, 2004). The main objectives of this study are to extract palaeoclimatic information considering, beside lithofacial characteristics and the isotopic distribution of carbonates formed in paleosols, the stable isotope composition of vertebrate remains from the Haţeg Basin. We also sampled several teeth along their growth axis in order to get further information about growth rates and the amplitude of isotopic variation. Located in the South Carpathians in Romania, the Haţeg Basin contains a thick sequence of Maastrichtian continental deposits yielding a rich dinosaur and mammalian fauna. Stable isotope analyses of both calcretes and dinosaur, crocodilian and turtle remains from two localities (Tuştea and Sibişel) were integrated in order to reconstruct environmental conditions during the Maastrichtian time and to gain further insights into the metabolism

  4. Phosphorus geochemistry of recent sediments in the South Basin of Lake Winnipeg

    USGS Publications Warehouse

    Mayer, T.; Simpson, S.L.; Thorleifson, L.H.; Lockhart, W.L.; Wilkinson, Philip M.

    2006-01-01

    Lake Winnipeg supports the largest commercial fishery on Canadian Prairies. It has been influenced by a variety of environmental forces and anthropogenic activities. To gain a better understanding of recent changes in nutrient status of the lake, it is important to reconstruct its previous history from sedimentary records. Lacustrine sediments are known to be an important sink of many dissolved and suspended substances, including phosphorus, hence, they provide a permanent historical record of changes occurring in the lake. These changes may be induced by natural factors or by anthropogenic activities in the watershed. Phosphorus profiles from dated sediment cores collected in 1999 and 1994 from the South Basin of Lake Winnipeg were investigated to determine phosphorus enrichment in recent sediments. To interpret the nutrient status and depositional conditions responsible for the trends in total phosphorus, three operationally defined forms of phosphorus (P) were determined: non-apatite inorganic P, apatite P, and organic P. Significant increases in sediment phosphorus concentrations were observed in the uppermost 20 cm of the cores and several anomalies were observed at depth. A doubling in total phosphorus relative to aluminum over the last fifty years is largely due to increases in the non-apatite inorganic fraction, suggesting that much of sedimentary phosphorus increase is attributable to changes in the nutrient status of the water column related to anthropogenic inputs. Organic phosphorus exhibits a subtle increase in the upper 20 cm of the gravity cores, likely due to increases in the primary productivity of the lake. Except for the slight increase in deeper sediments, apatite phosphorus, which is thought to be of detrital origin, remained fairly constant over the length of the cores. Anomalous spikes in phosphorus concentrations deeper in the cores, comprised mainly of the non-apatite inorganic phosphorus fraction, likely resulted from natural variation in

  5. Basins and the South Polar Terrain of Enceladus: Hotspots vs. Coldspots, and More Evidence for Crustal Spreading and Convergence

    NASA Astrophysics Data System (ADS)

    McKinnon, William B.; Schenk, P. M.

    2009-09-01

    Stereo-derived topographic mapping of 50% of Enceladus reveals at least 6 large-scale, ovoid depressions (basins) 90-175 km across and 800-to-1500 m deep and uncorrelated with geologic boundaries (Schenk and McKinnon, GRL, in press). Their shape and scale are inconsistent with impact, geoid deflection, or with dynamically supported topography. Isostatic thinning of Enceladus’ ice shell associated with upwellings (and tidally-driven ice melting) can plausibly account for the basins. Thinning implies upwarping of the base of the shell of 10-20 km beneath the depressions, depending on total shell thickness; loss of near-surface porosity due to enhanced heat flow may also contribute to basin lows. Alternatively, the basins may overly cold, inactive, and hence denser ice, but thermal isostasy alone requires thermal expansion more consistent with clathrate hydrate than water ice. In contrast to the basins, the south polar depression (SPD) is larger ( 350 wide) and shallower ( 0.4-to-0.8 km deep) and correlates with the area of tectonic deformation and active resurfacing. The SPD also differs in that the floor is relatively flat (i.e., conforms roughly to the global triaxial shape, or geoid) with broad, gently sloping flanks. The relative flatness across the SPD suggests that it is in or near isostatic equilibrium, and underlain by denser material, supporting the polar sea hypothesis of Collins and Goodman [2007]. Near flatness is also predicted by a crustal spreading origin for the "tiger stripes” [e.g., Barr, 2008]; the extraordinary, high CIRS heat flows imply half-spreading rates in excess of 10 cm/yr, a very young surface age ( 250,000 yr), and a rather thin lithosphere (hence modest thermal topography). Topographic rises in places along the outer margin of the SPD correlate with parallel ridges and deformation along the edge of the resurfaced terrain, consistent with a compressional, imbricate thrust origin for these ridges, driven by the spreading.

  6. Deep water deposits of the Tanqua and Laingsburg subbasins, southwest Karoo Basin, South Africa: Analog for the Gulf of Mexico

    SciTech Connect

    Scott, E.D.

    1995-10-01

    The Tanqua and Laingsburg subbasins in South Africa had near-contemporaneous formation and filling and contain Permian-age basin-floor and slope fans that display characteristics similar to deposits in the northern Gulf of Mexico. Outcrop area for each subbasin is about 650 km{sup 2} and individual fans range from 150 to 450 km{sup 2} with lateral continuity of individual fans up to 34 km. Both subbasins were influenced in their formation and in the architecture of their deposits by structures and events associated with the Cape Fold Belt. These fans most likely had a single point source which migrated over the time of basin fill. Unrestricted deposition suggests an open basin depositional setting. The Laingsburg subbasin was strongly influenced by the tectonism associated with the Cape Fold Belt. Deposition occurred in a deeper and narrower basin and the deposits, except for the overlying deltaics cannot be correlated with those of the Tanqua subbasin. The two subbasins, while associated with an active margin, were likely filled at slightly different times. Both had a distant source area which led to deposits exhibiting characteristics of a passive margin depositional environment. Understanding the evolution of the subbasins and the tectonic conditions under which the submarine fans were deposited leads to the determination of the mechanisms that influenced the formation of the fans and their resulting architecture. These fans permit detailed studies on their architecture necessary to (1) increase our understanding of fine-grained, {open_quotes}low{close_quotes} sandstone/shale ratio fans, (2) determine influences of paleostructures and tectonics on basin fill, (3) carry out detailed reservoir simulation programs, and (4) make predictive models of deep-water sands in the northern Gulf of Mexico.

  7. The linkage between longitudinal sediment routing systems and basin types in the northern South China Sea in perspective of source-to-sink

    NASA Astrophysics Data System (ADS)

    Su, Ming; Hsiung, Kan-Hsi; Zhang, Cuimei; Xie, Xinong; Yu, Ho-Shing; Wang, Zhenfeng

    2015-11-01

    Using bathymetric and seismic data, this study describes the morpho-sedimentary features in Qiongdongnan basin and southwest Taiwan collision basin, northern South China Sea and reveals the linkages between sediment routing system and basin types. The modern Central Canyon in the Qiongdongnan basin is located along the rift margin, and subparallel to the shelf-break southeast of Hainan Island. The modern Central Canyon develops along the basin axis (i.e., Xisha Trough) and longitudinally transports sediments eastward which are mainly supplied by northern continental slope. The Penghu Canyon in the southwest Taiwan collision basin is located along the collision boundary parallel to the strike of the adjacent uplifted Taiwan orogen. The Penghu Canyon develops along the tilting basin axis transporting sediments longitudinally southward to the deep-sea basin and Manila Trench. The Penghu Canyon is supplied with sediments from both flank Kaoping and South China Sea slopes where tributary canyons and channels transport sediments down-slope and feed the axial canyon. The certain basin types may be occupied by particular styles of sediment routing system. By comparing the morpho-sedimentary features and basin characteristics associated with the modern Central Canyon to that of the Valencia Channel in NW Mediterranean Sea, the longitudinal sediment routing system in rift basin type can be determined. In contrast, the longitudinal sediment routing systems in collision setting can be represented by the comparable examples of Penghu Canyon in southwest Taiwan collision basin and Markham Canyon in western Solomon Sea. The rift type sediment routing system is characterized by an axial canyon with a single sediment supply from land drainage margin. In contrast, sediment routing system in collision type basins consists of an axial canyon and dual sediment supplies from flank adjacent slopes. The axial canyons in collision basins are more active than that of the rift basin due to

  8. Bedrock morphology and structure, upper Santa Cruz Basin, south-central Arizona, with transient electromagnetic survey data

    USGS Publications Warehouse

    Bultman, Mark W.; Page, William R.

    2016-10-31

    susceptibilities of rocks found in the study area, and estimated natural remanent magnetic intensities and directions, reasonable geologic models can be built. This indicates that the depth to bedrock map is reason-able and geologically possible.Finally, CDTs derived from the 1998 Santa Cruz Basin transient electromagnetic survey were used to help identify basin structure and some physical properties of the basin fill in the study area. The CDTs also helped to confirm depth to bedrock estimates in the Santa Cruz Basin, in particular a region of elevated bedrock in the area of Potrero Canyon, and a deep basin in the location of the Arizona State Highway 82 microbasin. The CDTs identified many concealed faults in the study area and possibly indicate deep water-saturated clay-rich sediments in the west-central portion of the study area. These sediments grade to more sand-rich saturated sediments to the south with relatively thick, possibly unsaturated, sediments at the surface. Also, the CDTs may indicate deep saturated clay-rich sediments in the Highway 82 microbasin and in the Mount Benedict horst block from Proto Canyon south to the international border.

  9. Geology of the Williston basin, North Dakota, Montana, and South Dakota, with reference to subsurface disposal of radioactive wastes

    USGS Publications Warehouse

    Sandberg, C.A.

    1962-01-01

    The southern Williston basin, which underlies about 110,000 square miles #n North Dakota, South Dakota, and eastern Montana, is part of a large structural and sedimentary basin. Its surface is a flat to gently rolling plain, standing about 1,500 to 3,500 feet above sea level and locally studded by a few high buttes. The sedimentary sequence that fills the basin has a maximum thickness of about 16,700 feet and rests on Precambrian metamorphic rocks at depths of 500 to 13,900 feet below sea level. It contains rocks of every geologic system, from Cambrian to Quaternary. Rocks of Middle Cambrian through Middle Ordovician age are largely shale and sandstone, as much as 1,200 feet thick; rocks of Late Ordovician through Pennsylvanian age are largely limestone and dolomite, as much as 7,500 feet thick; and rocks of Permian through Tertiary age are predominantly shale and siltstone, as much as 8,000 feet thick. Pleistocene glacial drift mantles the northern and eastern parts of the area. Rocks of the Williston basin are gently folded and regional dips are 1? or less from the margins to the basin center. Dips on the flanks of the major anticlinal folds, the Nesson and cedar Creek anticlines and the Poplar and Bowdoin domes, generally are about 1? to 3? except on the steep west limb of the Cedar Creek anticline. The basin was shaped by Laramide orogeny during latest Cretaceous and early Tertiary time. Most of the present structural features, however, were initiated during the Precambrian and reactivated by several subsequent orogenies, of which the latest was the Laramide. The most important mineral resource of the area is oil, which is produced predominantly from the Paleozoic carbonate sequence and largely on three of the major anticlinal folds, and lignite, which is present near the surface in Paleocene rocks. The subsurface disposal of radioactive wastes at some places in the Williston basin appears to be geographically and geologically feasible. Many sites, at which

  10. Central South Atlantic kinematics: a 3D ocean basin-scale model of the Walvis Ridge and Rio Grande Rise

    NASA Astrophysics Data System (ADS)

    Bird, D. E.; Hall, S. A.

    2009-12-01

    Prior to the breakup of western Gondwana, ca. 130 Ma, the Tristan da Cuhna mantle plume produced the eastern South American Parana, and western African Etendeka, flood basalts. As the South Atlantic basin opened, the ridge-centered plume produced seaward extending hotspot tracks: Rio Grande Rise on the South American Plate, and Walvis Ridge on the African Plate. Several ocean floor edifices on the hotspot trends appear to produce lower than expected amplitude free air gravity anomalies, suggesting that they are composed of lower density material. We have constructed a 3D gravity model of the South Atlantic basin to examine variations in crustal density associated with the hot spot trends. The model, which encompasses a region that extends from 46°S to 10 °S and from 20°E to 60°W, comprises the following layers: water, sediment, crust, and upper mantle. Variable density sediment and upper mantle layers are incorporated to estimate density changes related to sediment thickness and compaction, and upper mantle temperatures, respectively. The initial Moho horizon is estimated from isostatic equilibrium calculations; however the isostatic effect is scaled away from the seafloor spreading center to simulate the active spreading center. Three open-file grids were used to generate the model: satellite-derived free air gravity, global topography, and sediment thickness of the world. Inverting the model for crustal density reveals a distribution of low-density areas: along the coasts, the seafloor spreading axis, and along the Rio Grande Rise and Walvis Ridge hotspot trends. Coastal and spreading axis low density areas are thought to be related to continental crust and high temperature upper mantle. Hotspot track low density areas might be related to variable densities within the volcanic edifices, variations in their crustal thickness, or upper mantle densities beneath them. Detailed 2D models approximate reasonable density and geometry limits along select transects

  11. Development of clarity model for Caspian Sea using MERIS data

    NASA Astrophysics Data System (ADS)

    Taheri Shahraini, Hamid; Sharifi, Hosein; Sanaeifar, Melika

    2011-11-01

    Secchi disc is often used to measure the clarity of water in oceans and lakes. In this study, an empirical model is developed for the monitoring of secchi disc depth (SD) in the Caspian Sea using satellite images. In situ measurements of secchi disc depth have been performed in the Caspian Sea between July and October 2005. The in situ water samples were taken during 25 one-day campaigns at different distances to the coast. Totally 37 secchi depth data of Caspian Sea were gathered. The database was divided to 25 and 12 data for training and testing of empirical models, respectively. A total of 25 Level 1B and 25 Level 2 MERIS images acquired over the Caspian Sea between July and October 2005 were used in this study. The level 1b and level 2 data are containing of remote sensing reflectance (Rrs) data of TOA (Top Of Atmosphere) and BOA (Bottom Of Atmosphere), respectively. The relation between secchi depth and Rrs, logarithm of Rrs, ratio of Rrs data and logarithm of ratio of Rrs data in different wavelengths for TOA and BOA data were investigated and then the highest correlation coefficient between secchi depth and mentioned Rrs parameters were selected and some empirical models were developed using them. The results showed that the modeling using BOA data can lead to better results than TOA. The best developed model using BOA data is as 1/SD=-0.138 +2.08*[Rrs(681nm)/Rrs(560nm)] with 28% error and with correlation coefficient equal to 0.86.

  12. Groundwater quality in the South Coast Range Coastal groundwater basins, California

    USGS Publications Warehouse

    Burton, Carmen A.; Belitz, Kenneth

    2013-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project (PBP) of the GAMA Program provides a comprehensive assessment of the State’s untreated groundwater quality and increases public access to groundwater-quality information. The coastal basins in the Southern Coast Ranges constitute one of the study units being evaluated.

  13. Constraining the sedimentology and stratigraphy of submarine intraslope lobe deposits using exhumed examples from the Karoo Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Spychala, Y. T.; Hodgson, D. M.; Flint, S. S.; Mountney, N. P.

    2015-06-01

    Intraslope lobe deposits provide a process record of the infill of accommodation on submarine slopes and their recognition enables the accurate reconstruction of the stratigraphic evolution of submarine slope systems. Extensive exposures of discrete sand-prone packages in Units D/E and E, Fort Brown Formation, Karoo Basin, South Africa, permit analysis of the sedimentology and stacking patterns of three intraslope lobe complexes and their palaeogeographic reconstruction via bed-scale analysis and physical correlation of key stratal surfaces. The sand-prone packages comprise tabular, aggradationally to slightly compensationally stacked lobe deposits with constituent facies associations that can be attributed to lobe axis, lobe off-axis, lobe-fringe and distal lobe-fringe environments. Locally, intraslope lobe deposits are incised by low aspect ratio channels that mark basinward progradation of the deepwater system. The origin of accommodation on the slope for lobe deposition is interpreted to be due to differential compaction or healing of scars from mass wasting processes. The stacking patterns and sedimentary facies arrangement identified in this study are distinct from those of more commonly recognized basin-floor lobe deposits, thereby enabling the establishment of recognition criteria for intraslope lobe deposits in other less well exposed and studied fine-grained systems. Compared to basin floor lobes, intraslope lobes are smaller in volume, influenced by higher degrees of confinement, and tend to show aggradational stacking patterns.

  14. The river basin game as a tool for collective water management at community level in South Africa

    NASA Astrophysics Data System (ADS)

    Magombeyi, M. S.; Rollin, D.; Lankford, B.

    Water scarcity in semi-arid catchments presents challenges on achieving equitable sharing of available water resources and avoiding social tensions among small-holder farmers. This paper explores the implementation of a river basin game as a tool to facilitate negotiations and rules of equal access among upstream and downstream irrigation water users in Ga-Sekororo, Olifants river basin in South Africa. The various stages of the game playing methodology are presented in a progressive manner and the outcomes are discussed. Through the application of this game, farmers were able to better relate to their catchment and accepted the board’s schematic representation of their reality. They were able to understand top-tail inequities of water supply and to appreciate that solutions lie in the community. The coming together of the small-holder farmers to share knowledge and set agreements on equitable water sharing results in higher benefits such as community harmony, transparency, acceptance of operating rules and improved knowledge to the community as a whole. The collective negotiation exercise produces more acceptable water allocation rules, thereby improving the security of water supply to the irrigation schemes. The paper concludes that local level management of tensions and conflicts through participation as facilitated by the river basin games can be sustainable provided there is proactive support from higher level institutions such as water committees, government and research.

  15. Extensional salt tectonics in the partially inverted Cotiella post-rift basin (south-central Pyrenees): structure and evolution

    NASA Astrophysics Data System (ADS)

    López-Mir, Berta; Muñoz, Josep Anton; García-Senz, Jesús

    2015-03-01

    The Cotiella Massif in the south-central Pyrenees hosts upper Cretaceous gravity-driven extensional faults which were developed in the Bay of Biscay-Pyrenean paleorift margin of the Atlantic Ocean. They accommodate up to 6 km of post-rift carbonates above relict upper Triassic salt. Subsequent Pyrenean contractional deformation preserved the main extensional features, but most of the upper Triassic salt was expulsed and then dissolved, leaving little indications of the original salt volume. Nonetheless, several distinctive salt-related features are still recognizable both at outcrop and at basin scale, providing an exposed analogue for salt-floored extensional basins developed on passive margins. Based on field research, we re-interpret the tectonic evolution of the area and suggest that passive diapirs were coeval with gravity-driven extension during the development of the Cotiella basin. The given interpretations are supported with detailed geological maps, original structural data, cross sections and outcrop photographs. The discovery of previously unknown post-rift salt structures in the Cotiella Massif is an extra element to consider in the paleogeographic reconstructions of the upper Cretaceous passive margin of the Bay of Biscay-Pyrenean realm and consequently helps in our understanding of the evolution of current Atlantic-type margins.

  16. Diversity and distribution of diazotrophic communities in the South China Sea deep basin with mesoscale cyclonic eddy perturbations.

    PubMed

    Zhang, Yao; Zhao, Zihao; Sun, Jun; Jiao, Nianzhi

    2011-12-01

    The South China Sea (SCS) is an oligotrophic subtropical marginal ocean with a deep basin and a permanently stratified central gyre. Upwelling and nitrogen fixation provide new nitrogen for primary production in the SCS. This study was aimed at an investigation of phylogenetic diversity and quantification of the diazotroph community in the SCS deep basin, which is characterized by frequent mesoscale eddies. The diazotroph community had a relatively low diversity but a distinct spatial heterogeneity of diversity in the SCS deep basin. The potential for nitrogen fixation consistently occurred during cyclonic eddies, although upwelling of nutrient-replete deep water might have alleviated nitrogen limitation in the SCS. However, diazotrophic proteobacteria were dominant, but neither Trichodesmium nor heterocystous cyanobacterial diatom symbionts. Quantitative PCR analysis using probe-primer sets developed in this study revealed that the nif H gene of the two dominant alpha- and gammaproteobacterial groups was at the highest abundance (up to 10(4) to 10(5)  copies L(-1) ). Trichodesmium thiebautii was detected with an average density of 10(2)  trichomes L(-1) in the euphotic waters, while Richelia intracellularis was observed sporadically under the microscope. The unicellular cyanobacterial groups A and B were not detected in our libraries. Our results suggested that diazotrophic proteobacteria were significant components potentially contributing to nitrogen fixation in this oligotrophic marginal ocean ecosystem.

  17. Fluid transport by solitary waves along growing faults. A field example from the South Eugene Island Basin, Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Revil, A.; Cathles, L. M.

    2002-09-01

    The Red Fault system is one of the main growth faults found in the South Eugene Island Basin, a salt withdrawal minibasin located offshore Louisiana, in the Gulf of Mexico. This fault system corresponds to a lateral boundary between fluid overpressured compartments. In addition, there is a set of observations indicating that the Red Fault system exhibits rapid episodic migration of fluids. This fault represents an example of preferential pathway for the upward episodic migration of overpressured hydrocarbons from deep, heavily pressured, compartments on time scales of years. The migrations of fluids into active growing faults could take the form of propagating surges (solitary waves) that propagate upward along the fault planes in a wave-like manner at km/yr. Solitary waves represent a very efficient mechanism for the upward transport of fluids along growth faults in sedimentary basins generating its own permeability. In addition, this mechanism is compatible with the fact that the fault plane is observed to sustain a static pore fluid pressure difference between its two sides. The propagation of solitary waves in active growth faults appears as a fundamental mechanism to understand the nature of upward fast migration of fluids along active growth faults in compartimentalized sedimentary basins.

  18. Breccia pipes in the Karoo Basin, South Africa, as conduits for metamorphic gases to the Early Jurassic atmosphere

    NASA Astrophysics Data System (ADS)

    Silkoset, Petter; Svensen, Henrik; Planke, Sverre

    2014-05-01

    The Toarcian (Early Jurassic) event was manifested by globally elevated temperatures and anoxic ocean conditions that particularly affected shallow marine taxa. The event coincided with the emplacement of the vast Karoo-Ferrar Large Igneous Province. Among the suggestions for trigger mechanisms for the climatic perturbation is metamorphic methane generation from black shale around the sills in the Karoo Basin, South Africa. The sill emplacement provides a mechanism for voluminous in-situ production and emission of greenhouse gases, and establishes a distinct link between basin-trapped and atmospheric carbon. In the lower stratigraphic levels of the Karoo Basin, black shales are metamorphosed around sills and the sediments are cut by a large number of pipe structures with metamorphic haloes. The pipes are vertical, cylindrical structures that contain brecciated and baked sediments with variable input of magmatic material. Here, we present borehole, petrographic, geochemical and field data from breccia pipes and contact aureoles based on field campaigns over a number of years (2004-2014). The metamorphism around the pipes show equivalent metamorphic grade as the sediments around nearby sills, suggesting a more prominent phreatomagmatic component than previously thought. The stratigraphic position of pipes and the breccia characteristics strengthens the hypothesis of a key role in the Toarcian carbon isotope excursion.

  19. The structure and sedimentary sequence of intracratonic rift from Late Sinian to Early Cambrian in the Sichuan Basin, South China

    NASA Astrophysics Data System (ADS)

    Gu, Zhidong; Zhang, Baomin; Lu, Weihu; Zhai, Xiufen; Jiang, Hua

    2016-04-01

    Sichuan Basin is located in the northwest of Upper Yangtze craton of South China, and there is developed an intracratonic rift from Late Sinian to Early Cambrian in the middle of Sichuan Basin, and the paper systematically discusses the structure and sedimentary sequence of the intracratonic rift based on the fields, drilling and seismic data, and so on. Detailed structural interpretation of 2D and 3D seismic profiles displays the development of two stages of intracratonic rift due to regional extension with the depth of 2000m, and plane distribution of intracratonic rift presents the V-pattern from the northwest to the southeast in the middle of Sichuan Basin with the width from 100km to 20km. The drilling data from the intracratonic rift shows the obvious thinning of Upper Sinian and thickening of Lower Cambrian. And field outcrops situated in the intracratonic rift reveal that the Upper Sinian is mainly composed of siliceous rock, shale and carbonate, with the thickness of less than 100m, but the thickness of Upper Sinian on the platform reaches 1000m by contrast; They also reveals that Lower Cambrian is mainly composed of shale, mudstone, and siltstone with the development of gravity current, and the thickness of Lower Cambrian reaches 2000m. The formation of intracratonic rift may be initiated by pre-existing basement weakness zone and deep mantle dynamics.

  20. Local Lunar Gravity Field Analysis over the South Pole-aitken Basin from SELENE Farside Tracking Data

    NASA Technical Reports Server (NTRS)

    Goossens, Sander Johannes; Ishihara, Yoshiaki; Matsumoto, Koji; Sasaki, Sho

    2012-01-01

    We present a method with which we determined the local lunar gravity field model over the South Pole-Aitken (SPA) basin on the farside of the Moon by estimating adjustments to a global lunar gravity field model using SELENE tracking data. Our adjustments are expressed in localized functions concentrated over the SPA region in a spherical cap with a radius of 45deg centered at (191.1 deg E, 53.2 deg S), and the resolution is equivalent to a 150th degree and order spherical harmonics expansion. The new solution over SPA was used in several applications of geophysical analysis. It shows an increased correlation with high-resolution lunar topography in the frequency band l = 40-70, and admittance values are slightly different and more leveled when compared to other, global gravity field models using the same data. The adjustments expressed in free-air anomalies and differences in Bouguer anomalies between the local solution and the a priori global solution correlate with topographic surface features. The Moho structure beneath the SPA basin is slightly modified in our solution, most notably at the southern rim of the Apollo basin and around the Zeeman crater

  1. Probability of Potential Multi-Canister Overpack Loading System Drop of Proof Load in the K West Basin South Loadout Pit

    SciTech Connect

    SHULTZ, M.V.

    2000-01-20

    This document presents the results of a probabilistic analysis of the potential for load drop during the load test of the K West Basin South Loadout Pit Gantry. The calculations are in support of the cask loading system (CLS) subproject load test of the gantry. The purpose of this calculation note is to document the probabilistic calculation of the per lift potential for drop of a test load by the Multi-Canister Overpack (MCO) Loading System (MLS) during load testing at the K West Basin south loadout pit. The MLS subproject needs to load test the MLS in the K West Basin south loadout pit. To perform this test, a basket mockup weighing approximately 4,500 lb (125% of a fully loaded MCO basket accounting for water displacement) needs to be used for one or more load tests. The test load will comprise a standard basket lifting attachment with several ring-shaped steel segments to provide the required weight. The test load will exceed the K Basin Safety Analysis Report (WHC-SD-WM-SAR-062) (SAR) allowances for load drop in the K West Basin south loadout pit. This probabilistic calculation will be used as part of the basis for seeking U.S. Department of Energy approval to use an MLS test weight that exceeds SAR allowances.

  2. The effect of plate movements in the northern region of South America on tectonics and sedimentation in the Eastern Llanos Basin

    SciTech Connect

    Pena, L.E. )

    1993-02-01

    The geological configuration of the Eastern Llanos pericratonic mega-basin has been directly affected by the overall tectonic regime experienced in the Northern part of South America. Interaction between the Pacific (Cocos), South American and Caribbean Plates generated a regional compressional dextral rotational force expressed as a regional North-South striking structural trend in the southern part of the basin and an east-west striking trend in portion nearest the Caribbean Plate Boundary. Nearly 90% of the strike-slip faults in this northern area show right lateral displacement. The majority of the structures in the East Llanos basin are related to the Late Miocene uplift of the Eastern Andes. Nevertheless we can subdivide the structures into two major groups: pre-Miocene and post-Miocene. By being able to recognize pre-Miocene Cretaceous age structures, much altered by later movements, we can envision remigration of hydrocarbons out of early traps into those created more recently. Plate tectonic events in the north of South America have produced a general regional structure strike directional through time. Sedimentary-tectonic relationships depend upon regional phenomena which, if interpreted correctly, help to sub-divide the mega-basin into genetically related parts. By understanding the mechanism that creates large scale structural features, the geologist is thus provided with an important tool that can aid him in exploring the Eastern Llanos basin.

  3. Microbial community composition and diversity in Caspian Sea sediments

    PubMed Central

    Mahmoudi, Nagissa; Robeson, Michael S.; Castro, Hector F.; Fortney, Julian L.; Techtmann, Stephen M.; Joyner, Dominique C.; Paradis, Charles J.; Pfiffner, Susan M.; Hazen, Terry C.

    2014-01-01

    The Caspian Sea is heavily polluted due to industrial and agricultural effluents as well as extraction of oil and gas reserves. Microbial communities can influence the fate of contaminants and nutrients. However, insight into the microbial ecology of the Caspian Sea significantly lags behind other marine systems. Here we describe microbial biomass, diversity and composition in sediments collected from three sampling stations in the Caspian Sea. Illumina sequencing of 16S rRNA genes revealed the presence of a number of known bacterial and archaeal heterotrophs suggesting that organic carbon is a primary factor shaping microbial communities. Surface sediments collected from bottom waters with low oxygen levels were dominated by Gammaproteobacteria while surface sediments collected from bottom waters under hypoxic conditions were dominated by Deltaproteobacteria, specifically sulfate-reducing bacteria. Thaumarchaeota was dominant across all surface sediments indicating that nitrogen cycling in this system is strongly influenced by ammonia-oxidizing archaea. This study provides a baseline assessment that may serve as a point of reference as this system changes or as the efficacy of new remediation efforts are implemented. PMID:25764536

  4. Microbial community composition and diversity in Caspian Sea sediments.

    PubMed

    Mahmoudi, Nagissa; Robeson, Michael S; Castro, Hector F; Fortney, Julian L; Techtmann, Stephen M; Joyner, Dominique C; Paradis, Charles J; Pfiffner, Susan M; Hazen, Terry C

    2015-01-01

    The Caspian Sea is heavily polluted due to industrial and agricultural effluents as well as extraction of oil and gas reserves. Microbial communities can influence the fate of contaminants and nutrients. However, insight into the microbial ecology of the Caspian Sea significantly lags behind other marine systems. Here we describe microbial biomass, diversity and composition in sediments collected from three sampling stations in the Caspian Sea. Illumina sequencing of 16S rRNA genes revealed the presence of a number of known bacterial and archaeal heterotrophs suggesting that organic carbon is a primary factor shaping microbial communities. Surface sediments collected from bottom waters with low oxygen levels were dominated by Gammaproteobacteria while surface sediments collected from bottom waters under hypoxic conditions were dominated by Deltaproteobacteria, specifically sulfate-reducing bacteria. Thaumarchaeota was dominant across all surface sediments indicating that nitrogen cycling in this system is strongly influenced by ammonia-oxidizing archaea. This study provides a baseline assessment that may serve as a point of reference as this system changes or as the efficacy of new remediation efforts are implemented. PMID:25764536

  5. The geology of Northern Sabah, Malaysia: Its relationship to the opening of the South China Sea Basin

    NASA Astrophysics Data System (ADS)

    Tongkul, F.

    1994-07-01

    The northern part of Sabah, consisting of sedimentary and igneous rocks of Early Cretaceous to Pliocene age, has experienced three major episodes of deformation associated with NW-SE and N-S oriented compressions. The earliest episode deformed and uplifted an oceanic basement (Chert-Spilite Formation) to form an elongate basin, trending approximately NE-SW, during the Late Cretaceous to Early Eocene. This elongate basin became the site for the deposition of middle Eocene to Early Miocene quartzose sediments of the Crocker and Kudat formations, sourced from continental basement towards the southwest and north, respectively. These sediments were subsequently deformed by a second episode of deformation associated with NW-SE and N-S oriented compressions, during the latter part of the late Oligocene and the early Middle Miocene, to form a series of imbricate thrust slices. The N-S trending compressive direction controlled the development of approximately E-W trending basins during the deposition of the Upper Miocene sediments of the South Banggi and Bongaya formations. The continuation of N-S compression, which represents the third episode of deformation, gently deformed these sediments. The three episodes of deformation were related to the differential southward movements of continental blocks separated from the southern margin of China during the intermittent opening of the South China Sea subbasins. The first episode was related to the opening of the Southwest Subbasin, while the second episode was related to both the opening of the Southwest and East subbasins. The third episode was related to continued opening in the East Subbasins.

  6. Tectonothermal history of an exhumed thrust-sheet-top basin: An example from the south Pyrenean thrust belt

    NASA Astrophysics Data System (ADS)

    Labaume, Pierre; Meresse, Florian; Jolivet, Marc; Teixell, Antonio; Lahfid, Abdeltif

    2016-05-01

    This paper presents a new balanced structural cross section of the Jaca thrust-sheet-top basin of the southern Pyrenees combined with paleothermometry and apatite fission track (AFT) thermochronology data. The cross section, based on field data and interpretation of industrial seismic reflection profiles, allows refinement of previous interpretations of the south directed thrust system, involving the identification of new thrust faults, and of the kinematic relationships between basement and cover thrusts from the middle Eocene to the early Miocene. AFT analysis shows a southward decrease in the level of fission track resetting, from totally reset Paleozoic rocks and lower Eocene turbidites (indicative of heating to Tmax > ~120°C), to partially reset middle Eocene turbidites and no/very weak resetting in the upper Eocene-lower Oligocene molasse (Tmax < ~60°C). AFT results indicate a late Oligocene-early Miocene cooling event throughout the Axial Zone and Jaca Basin. Paleomaximum temperatures determined by vitrinite reflectance measurements and Raman spectroscopy of carbonaceous material reach up to ~240°C at the base of the turbidite succession. Inverse modeling of AFT and vitrinite reflectance data with the QTQt software for key samples show compatibility between vitrinite-derived Tmax and the AFT reset level for most of the samples. However, they also suggest that the highest temperatures determined in the lowermost turbidites correspond to a thermal anomaly rather than burial heating, possibly due to fluid circulation during thrust activity. From these results, we propose a new sequential restoration of the south Pyrenean thrust system propagation and related basin evolution.

  7. Structure of pre-Caspian depression and major oil and gas fields of the region

    SciTech Connect

    Krylov, N.A. ); Avrov, V.P. ); Lisovsky, N.N.

    1991-03-01

    As a single unified depression, the pre-Caspian basin has been formed from Paleozoic to Cenozoic time. The basin is superimposed on two large pre-Permian depressions. On the Astrakhan-Aktyubinsk zone of uplifts between them is found sharply reduced Carboniferous and Devonian sections. Modern structural plan clearly displays two major structural stages: Subsalt (Paleozoic) and post (post-Kungurian). The post-salt stage is characterized by wide development of salt dome tectonics. It corresponds with its own petroliferous stage containing numerous, mostly small oil accumulations in terrigenous Mesozoic reservoirs. Large recent discoveries-Astrakhan condensate, Karachaganak and Kanazhol-Sinelnikov oil/condensate, Tengiz oil, and other fields-are associated with the Subsalt Paleozoic complex ranging from Lower Permian to the top of Upper Devonian. The Subsalt stage has its own regularities in hydrocarbon phase differentiation; large reserves concentration; dominantly productive carbonates with various reservoirs; and presence of structural, depositional, and erosional factors controlling formation of oil and gas traps. The paper describes major distributional features of the various arc-and-type Permian and Carboniferous formations, which in conjunction with Subsalt paleotemperature data and geochemistry of organic matter represents a basis for the forecast of new discoveries.

  8. Vitrinite reflectance data for Cretaceous marine shales and coals in the Bighorn Basin, north-central Wyoming and south-central Montana

    USGS Publications Warehouse

    Pawlewicz, Mark J.; Finn, Thomas M.

    2012-01-01

    The Bighorn Basin is a large Laramide (Late Cretaceous through Eocene) structural and sedimentary basin that encompasses about 10,400 square miles in north-central Wyoming and south-central Montana. The purpose of this report is to present new vitrinite reflectance data collected from Cretaceous marine shales and coals in the Bighorn Basin to better characterize the thermal maturity and petroleum potential of these rocks. Ninety-eight samples from Lower Cretaceous and lowermost Upper Cretaceous strata were collected from well cuttings from wells stored at the U.S. Geological Survey (USGS) Core Research Center in Lakewood, Colorado.

  9. Development of a precipitation-runoff model to simulate unregulated streamflow in the South Fork Flathead River Basin, Montana

    USGS Publications Warehouse

    Chase, K.J.

    2011-01-01

    This report documents the development of a precipitation-runoff model for the South Fork Flathead River Basin, Mont. The Precipitation-Runoff Modeling System model, developed in cooperation with the Bureau of Reclamation, can be used to simulate daily mean unregulated streamflow upstream and downstream from Hungry Horse Reservoir for water-resources planning. Two input files are required to run the model. The time-series data file contains daily precipitation data and daily minimum and maximum air-temperature data from climate stations in and near the South Fork Flathead River Basin. The parameter file contains values of parameters that describe the basin topography, the flow network, the distribution of the precipitation and temperature data, and the hydrologic characteristics of the basin soils and vegetation. A primary-parameter file was created for simulating streamflow during the study period (water years 1967-2005). The model was calibrated for water years 1991-2005 using the primary-parameter file. This calibration was further refined using snow-covered area data for water years 2001-05. The model then was tested for water years 1967-90. Calibration targets included mean monthly and daily mean unregulated streamflow upstream from Hungry Horse Reservoir, mean monthly unregulated streamflow downstream from Hungry Horse Reservoir, basin mean monthly solar radiation and potential evapotranspiration, and daily snapshots of basin snow-covered area. Simulated streamflow generally was in better agreement with observed streamflow at the upstream gage than at the downstream gage. Upstream from the reservoir, simulated mean annual streamflow was within 0.0 percent of observed mean annual streamflow for the calibration period and was about 2 percent higher than observed mean annual streamflow for the test period. Simulated mean April-July streamflow upstream from the reservoir was about 1 percent lower than observed streamflow for the calibration period and about 4

  10. Origin of andesitic rocks: Geochemical constraints from Mesozoic volcanics in the Luzong basin, South China

    NASA Astrophysics Data System (ADS)

    Chen, Long; Zhao, Zi-Fu; Zheng, Yong-Fei

    2014-03-01

    A combined study of whole-rock major-trace elements and Sr-Nd-Pb-Hf isotopes as well as zircon U-Pb ages and Hf-O isotopes was carried out for Mesozoic andesitic-basaltic volcanics from the Luzong basin in the Middle-Lower Yangtze River Belt, South China. The results provide insights into the origin of mantle sources above fossil Andes-type oceanic subduction zone and thus into the petrogenesis of andesitic rocks on fossil and modern continental margins. These volcanics are primarily composed of basaltic trachyandesite and trachyandesite, with small amounts of trachybasalt and trachyte. They exhibit variable contents of SiO2 (48.66-63.43 wt.%), MgO (0.39-4.85 wt.%), Na2O (1.22-6.07 wt.%) and K2O (2.53-10.10 wt.%), with highly variable K2O/Na2O ratios from 0.45 to 7.39. They are characterized by arc-like trace element distribution patterns, with significant enrichment of LILE, Pb and LREE but depletion of HFSE. They exhibit relatively enriched Sr-Nd-Pb-Hf isotope compositions, with initial 87Sr/86Sr ratios of 0.7050 to 0.7066, negative ɛNd(t) values of - 8.0 to - 3.1, negative ɛHf(t) values of - 11.1 to - 1.1, and elevated 207Pb/204Pb and 208Pb/204Pb ratios at given 206Pb/204Pb ratios. Zircon U-Pb dating yields consistent ages of 127 ± 2 to 137 ± 1 Ma for magma emplacement through volcanic eruption. The zircon exhibits slightly high δ18O values of 5.3 to 7.6‰ and variable ɛHf(t) values of - 13.1 to 2.6. An integrated interpretation of all these geochemical data leads to the conclusion that the Luzong andesitic-basaltic volcanics were primarily derived from partial melting of fertile and enriched, mafic-ultramafic mantle sources that are similar to those of continental arc andesites. Such mantle sources are hypothesized to form by reaction of the mantle wedge peridotite not only with hydrous felsic melts derived from partial melting of seafloor sediment but also with aqueous fluid derived from metamorphic dehydration of altered oceanic basalt during

  11. High Resolution Mapping of the Lunar South Pole-Aitken Basin Interior

    NASA Astrophysics Data System (ADS)

    Archinal, B. A.; Gaddis, L. R.; Hare, T. M.; Rosiek, M.; Howington-Kraus, E.; Lee, E.; Weller, L.; Kirk, R. L.; Edmundson, K.; Becker, T.; Jolliff, B. L.; Tran, T.; Robinson, M.; LROC Science Team

    2010-12-01

    We are making geodetically controlled high-resolution digital terrain models (DTMs) and image orthomosaics of the Constellation (Cx) Program region of interest (ROI) in the lunar South Pole-Aitken Basin interior (“SAB”) (center at 200.06° E, 60.00° S). This work is part of the Lunar Mapping and Modeling Program (LMMP), a NASA-funded effort to create useful cartographic products from past and current lunar datasets and to serve them on a web portal. The SAB is one of 50 ROIs chosen by Cx as potential sites for future robotic or human landings or analogs thereof. Source data for our products includes publically released ~50 cm/pixel Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera images and Lunar Orbiter Laser Altimeter (LOLA) spot elevation measurements and preliminary global 16 posts/° DTM. Products generated so far include: a) a preliminary stereo DTM covering ~25% of the center 20 km square area of the ROI, with post spacing (resolution) of 1.5 m and ~86x10^6 posts; b) a preliminary mosaic of 90% of the 40 km square ROI, with a resolution of 2 m, orthorectified with LOLA data or, where possible, the stereo DTM; c) preliminary DTMs generated via the use of photoclinometry (“shape from shading”), covering small areas with post spacing of 50 cm; and d) slope and roughness maps derived from a and c. All products are in the lunar mean Earth/polar axis coordinate system and the preliminary global reference frame of the current LOLA DTM. The absolute accuracy of these products is limited by the horizontal and vertical accuracy of the LOLA DTM, to which they are tied (DTMs and mosaics) or on which they are projected (mosaics). The expected vertical precision of the stereo DTM is ~20 cm. The products will soon be publically available via the LMMP portal and also via the USGS planetary GIS site, http://webgis.wr.usgs.gov/. Final versions tied to the LOLA nominal mission global DTM will be available in 2011 October. Preliminary analyses of these

  12. Simulation of ground-water flow in the basin-fill aquifer of the Tularosa Basin, south-central New Mexico, predevelopment through 2040

    USGS Publications Warehouse

    Huff, Glenn F.

    2005-01-01

    the agricultural area near Tularosa and decreasingly sensitive to the south. Declines in simulated water levels near Tularosa between 1948 and 1995 were as large as 30 meters under the zero return-flow scenario and 15 meters under the maximum return-flow scenario. Declines in simulated water levels between 1995 and 2040 were as large as 25 meters under the zero return-flow scenario and 15 meters under the maximum return-flow scenario. Comparison of water levels measured near Tularosa in 1991 and water levels simulated under the maximum return-flow scenario for 1991 suggests that declines in simulated water levels near Tularosa may be overestimated under the zero return-flow scenario. Declines in simulated water levels near the City of Alamogordo well field between 1948 and 1995 were as large as 15 meters under the zero return-flow scenario and 10 meters under the maximum return-flow scenario. Simulated declines in water levels between 1995 and 2040 were nearly 15 meters under both return-flow scenarios assuming that all projected increases in withdrawal came from existing City of Alamogordo public-supply wells and all withdrawal from the wells came from the basin-fill aquifer. Declines in simulated water levels near the Holloman Air Force Base well fields between 1948 and 1995 and between 1995 and 2040 were less than 5 meters under both the zero and maximum return-flow scenarios. In 1995 under the zero return-flow scenario, an estimated 56,000 cubic meters of water per day was removed from aquifer storage. Of the approximately 199,000 cubic meters of water per day that left the aquifer under 1995 conditions, 40 percent left the basin-fill aquifer as ground-water withdrawal, 51 percent as evapotranspiration, 7 percent by interbasin ground-water flow into the Hueco Bolson, and 2 percent by flow into creeks and springs. Generalized directions of ground-water flow were simulated for 1948, 1995, and 2040 for much of the eastern part of the Tularosa Basin. Localized

  13. BOLIVAR and GULFREX MCS Data Constrain Closure of the Grenada Backarc Basin During Oblique Collision Between the Lesser Antilles Arc System and Northern South America

    NASA Astrophysics Data System (ADS)

    Aitken, T. J.; Mann, P.; Christeson, G.

    2004-12-01

    The Lesser Antilles evolved from the mid-Cretaceous as an extensional arc system formed above a steeply dipping slab of Atlantic oceanic crust. The arc became extensional during the Paleocene - early Eocene along normal faults at the eastern edge of the basin as the present-day Lesser Antilles chain rifted away from the Aves Ridge. Backarc rifting ceased during the early Eocene, leaving the 140 km wide 3 km deep Grenada backarc basin. Sediment accumulation reached nearly 8 km during the Paleogene with another 1.5 km of sediments accumulating during the Neogene. In this presentation, we combine newly acquired MCS lines from the BOLIVAR study with existing GULFREX data collected in 1975 to document the structural and stratigraphic effects of closure of the Grenada backarc basin because of the progressive, oblique collision between the Lesser Antilles arc system and northern South America. The southern end of the Grenada basin has been narrowed from an undeformed width of approximately 100 km to a deformed width of 30 km, and rotated nearly 90 degrees to the west as the arc system obliquely collides with the South American margin. Shortening of the colliding backarc basin is mainly accommodated by inversion of Paleogene normal faults on the eastern edge of the basin, folding, low-angle thrust faults, and possibly shale diapirism. We propose that this closure in the area is a backthrusting response during Oligocene - late Miocene closure along the leading edge of the oblique arc-continent collision in the Eastern Venezuelan basin.

  14. Future water resources for food production in five South Asian river basins and potential for adaptation--a modeling study.

    PubMed

    Biemans, H; Speelman, L H; Ludwig, F; Moors, E J; Wiltshire, A J; Kumar, P; Gerten, D; Kabat, P

    2013-12-01

    The Indian subcontinent faces a population increase from 1.6 billion in 2000 towards 2 billion around 2050. Therefore, expansion of agricultural area combined with increases in productivity will be necessary to produce the food needed in the future. However, with pressure on water resources already being high, and potential effects of climate change still uncertain, the question rises whether there will be enough water resources available to sustain this production. The objective of this study is to make a spatially explicit quantitative analysis of water requirements and availability for current and future food production in five South Asian basins (Indus, Ganges, Brahmaputra, Godavari and Krishna), in the absence or presence of two different adaptation strategies: an overall improvement in irrigation efficiency, and an increase of reservoir storage capacity. The analysis is performed by using the coupled hydrology and crop production model LPJmL. It is found that the Godavari and Krishna basins will benefit most from an increased storage capacity, whereas in the Ganges and the Indus water scarcity mainly takes place in areas where this additional storage would not provide additional utility. Increasing the irrigation efficiency will be beneficial in all basins, but most in the Indus and Ganges, as it decreases the pressure on groundwater resources and decreases the fraction of food production that would become at risk because of water shortage. A combination of both options seems to be the best strategy in all basins. The large-scale model used in this study is suitable to identify hotspot areas and support the first step in the policy process, but the final design and implementation of adaptation options requires supporting studies at finer scales. PMID:23928370

  15. Heat flow in Railroad Valley, Nevada and implications for geothermal resources in the south-central Great Basin

    USGS Publications Warehouse

    Williams, C.F.; Sass, J.H.

    2006-01-01

    The Great Basin is a province of high average heat flow (approximately 90 mW m-2), with higher values characteristic of some areas and relatively low heat flow (<60 mW m-2) characteristic of an area in south-central Nevada known as the Eureka Low. There is hydrologie and thermal evidence that the Eureka Low results from a relatively shallow, hydrologically controlled heat sink associated with interbasin water flow in the Paleozoic carbonate aquifers. Evaluating this hypothesis and investigating the thermal state of the Eureka Low at depth is a high priority for the US Geological Survey as it prepares a new national geothermal resource assessment. Part of this investigation is focused on Railroad Valley, the site of the largest petroleum reservoirs in Nevada and one of the few locations within the Eureka Low with a known geothermal system. Temperature and thermal conductivity data have been acquired from wells in Railroad Valley in order to determine heat flow in the basin. The results reveal a complex interaction of cooling due to shallow ground-water flow, relatively low (49 to 76 mW m-2) conductive heat flow at depth in most of the basin, and high (up to 234 mW m-2) heat flow associated with the 125??C geothermal system that encompasses the Bacon Flat and Grant Canyon oil fields. The presence of the Railroad Valley geothermal resource within the Eureka Low may be reflect the absence of deep ground-water flow sweeping heat out of the basin. If true, this suggests that other areas in the carbonate aquifer province may contain deep geothermal resources that are masked by ground-water flow.

  16. Effects of urbanization on agricultural lands and river basins: case study of Mersin (South of Turkey).

    PubMed

    Duran, Celalettin; Gunek, Halil; Sandal, Ersin Kaya

    2012-04-01

    Largely, Turkey is a hilly and mountainous country. Many rivers rise from the mountains and flow into the seas surrounding the country. Mean while along fertile plains around the rivers and coastal floodplains of Turkey were densely populated than the other parts of the country. These characteristics show that there is a significant relationship between river basins and population or settlements. It is understood from this point of view, Mersin city and its vicinity (coastal floodplain and nearby river basins) show similar relationship. The city of Mersin was built on the southwest comer of Cukurova where Delicay and Efrenk creeks create narrow coastal floodplain. The plain has rich potential for agricultural practices with fertile alluvial soils and suitable climate. However, establishment of the port at the shore have increased commercial activity. Agricultural and commercial potential have attracted people to the area, and eventually has caused rapid spatial expansion of the city, and the urban sprawls over fertile agricultural lands along coastal floodplain and nearby river basins of the city. But unplanned, uncontrolled and illegal urbanization process has been causing degradation of agricultural areas and river basins, and also causing flooding in the city of Mersin and its vicinity. Especially in the basins, urbanization increases impervious surfaces throughout watersheds that increase erosion and runoff of surface water. In this study, the city of Mersin and its vicinity are examined in different ways, such as land use, urbanization, morphology and flows of the streams and given some directions for suitable urbanization.

  17. Applied velocity versus offset (VVO) to validated & characterized fracturing zone in intra Baturaja Formation, South Sumatera Basin

    NASA Astrophysics Data System (ADS)

    Mardiyan, Hilman; Rusli, Saifatur

    2016-01-01

    The velocity versus offset (VVO) as new geophysical method can be applied to detect some geological phenomenon, such as hydrocarbon trap, structural-fracture anomaly, facies changes, etc. The VVO method is data driven, based on the normal move out equation (NMO) and measuring the local event correlation between adjacent traces to get velocity gradient attributes which is derived from cross-plotting the velocity versus offset (VVO). This paper is describing applied VVO model that controlled by well data which indicated fracture from logs data, especially Resistivity Imager Logs or Formation Micro Imager (FMI). Images FMI logs data at Intra-Baturaja Carbonate Formation (BRF) in South Palembang Sub-basin (SPB), South Sumatera, shows vugs with fractures which orientation is roughly NNW-SSE. Meanwhile, the 2D NMO seismic gathers indicated those all as hockey stick at far offset. By applying VVO method, hockey stick can be identified and then used to validated, characterized and localized where the fracturing zone in intra-Baturaja Formation is. Laterally, VVO quantified as velocity gradient attribute which associated with geological model as the fracturing zone in study area. Characterization fracturing zone in Intra Baturaja Formation as geological lateral model by design is a challenging task for most exploration and production. In term of exploration where limited data is available, it can be used step ahead as carbonate fracture reservoir candidate in proven area and adjacent, especially in SPB South Sumatra.

  18. The geochemistry characteristic and dating of cold seepage carbonates of the Pearl River Mouth Basin, eastern of South China Sea

    NASA Astrophysics Data System (ADS)

    Fang, Yunxin; Fu, Shaoying

    2015-04-01

    Cold seepage carbonates are usually formed by the interaction of methane oxidizing archaea, sulfate reducing bacteria and cold seepage which contain abundant venting hydrocarbon gases. The presence of cold seepage carbonates on the seabed is one of the evidences that the area exist venting hydrocarbon gases, which are usually result by the dissociation of gas hydrate. The cold seepage property and fluid flow rate can influence the oxidation-deoxidation environment of the bottom water and sediment. Many previous studies focused on the mineral composition, microstructure, elemental composition, isotope composition of the cold seepage carbonates and isotopic dating for the cold seepage carbonates. The isotopic dating for the cold seepage carbonates can provide the information of the gas hydrate formation and dissociation in some area of the South China Sea. High precision TIMS-U dating and 14C dating are used as routine method for the dating of the Quaternary carbonates and fossils. The cold seepage carbonates in the study include the samples collected by ROV on the seabed and the drilling for gas hydrate in the Pearl River Mouth Basin, eastern of the South China Sea. The authigenic carbonate occurred in different depth in the A, B and C drilling site. They may be represent different events of gas hydrate formation and dissociation in the Quaternary. The dating study for all the cold seepage carbonates can provide the relative accurate eras of the gas hydrate dissociation events in certain area of the South China Sea.

  19. Major controlling factors on hydrocarbon generation and leakage in South Atlantic conjugate margins: A comparative study of Colorado, Orange, Campos and Lower Congo basins

    NASA Astrophysics Data System (ADS)

    Marcano, Gabriela; Anka, Zahie; di Primio, Rolando

    2013-09-01

    We present a supra-regional comparative study of the major internal and external factors controlling source rock (SR) maturation and hydrocarbon (HC) generation and leakage in two pairs of conjugate margins across the South Atlantic: the Brazil (Campos Basin)-Angola (Lower Congo Basin) margins located in the "central segment", and the Argentina (Colorado Basin)-South Africa (Orange Basin) in the "southern segment". Our approach is based on the analysis and integration of borehole data, 1D numerical modeling, 2D seismic reflection data, and published reports. Coupling of modeling results, sedimentation rate calculation and seal-bypass system analysis reveal that: (1) oil window is reached by syn-rift SRs in the southern segment during the Early to Late Cretaceous when thermal subsidence is still active, while in the central segment they reach it in Late-Cretaceous-Neogene during a salt remobilization phase, and (2) early HC generation from post-rift SRs in the southern segment and from all SRs in the central segment appears to be controlled mainly by episodes of increased sedimentation rates. The latter seems to be associated with the Andes uplift history for the western South Atlantic basins (Campos and Colorado) and to a possibly climate-driven response for the eastern South Atlantic basins (Orange and Lower Congo). Additionally, we observe that the effect of volcanism on SR maturation in the southern segment is very local. The comparison of Cretaceous mass transport deposit (MTD) episodes with HC peak of generation and paleo-leakage indicators in the southern segment revealed the possible causal effect that HC generation and leakage have over MTD development. Interestingly, Paleogene leakage indicators, which were identified in the Argentina-South Africa conjugate margins, occur contemporaneously to low sedimentation rate periods. Nonetheless, present-day leakage indicators which were also identified in both pairs of conjugate margins might be related to seal

  20. Chapter A. Effects of urbanization on stream ecosystems in the South Platte River basin, Colorado and Wyoming

    USGS Publications Warehouse

    Sprague, Lori A.; Zuellig, Robert E.; Dupree, Jean A.

    2006-01-01

    This report describes the effects of urbanization on physical, chemical, and biological characteristics of stream ecosystems in 28 basins along an urban land-use gradient in the South Platte River Basin, Colorado and Wyoming, from 2002 through 2003. Study basins were chosen to minimize natural variability among basins due to factors such as geology, elevation, and climate and to maximize coverage of different stages of urban development among basins. Because land use or population density alone often are not a complete measure of urbanization, land use, land cover, infrastructure, and socioeconomic variables were integrated in a multimetric urban intensity index to represent the degree of urban development in each study basin. Physical characteristics studied included stream hydrology, stream temperature, and habitat; chemical characteristics studied included nutrients, pesticides, suspended sediment, sulfate, chloride, and fecal bacteria concentrations; and biological characteristics studied included algae, fish, and invertebrate communities. Semipermeable membrane devices (SPMDs), passive samplers that concentrate trace levels of hydrophobic organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), also were used. The objectives of the study were to (1) examine physical, chemical, and biological responses along the gradient of urbanization; (2) determine the major physical, chemical, and landscape variables affecting the structure of aquatic communities; and (3) evaluate the relevance of the results to the management of water resources in the South Platte River Basin. Commonly observed effects of urbanization on instream physical, chemical, and biological characteristics, such as increased flashiness, higher magnitude and more frequent peak flows, increased concentrations of chemicals, and changes in aquatic community structure, generally were not observed in this study. None of the hydrologic, temperature, habitat

  1. Application of sequence stratigraphy to carbonate reservoir prediction, Early Palaeozoic eastern Warburton basin, South Australia

    SciTech Connect

    Xiaowen S.; Stuart, W.J.

    1996-01-01

    The Early Palaeozoic Warburton Basin underlies the gas and oil producing Cooper and Eromanga Basins. Postdepositional tectonism created high potential fracture porosities, complicating the stratigraphy and making reservoir prediction difficult. Sequence stratigraphy integrating core, cuttings, well-log, seismic and biostratigraphic data has recognized a carbonate-dominated to mixed carbonate/siliciclastic supersequence comprising several depositional sequences. Biostratigraphy based on trilobites and conodonts ensures reliable well and seismic correlations across structurally complex areas. Lithofacies interpretation indicates sedimentary environments ranging from carbonate inner shelf, peritidal, shelf edge, deep outer shelf and slope to basin. Log facies show gradually upward shallowing trends or abrupt changes indicating possible sequence boundaries. With essential depositional models and sequence analysis from well data, seismic facies suggest general reflection configurations including parallel-continuous layered patterns indicating uniform neuritic shelf, and mounded structures suggesting carbonate build-ups and pre-existing volcanic relief. Seismic stratigraphy also reveals inclined slope and onlapping margins of a possibly isolated platform geometry. The potential reservoirs are dolomitized carbonates containing oomoldic, vuggy, intercrystalline and fracture porosities in lowstand systems tracts either on carbonate mounds and shelf crests or below shelf edge. The source rock is a deep basinal argillaceous mudstone, and the seal is fine-grained siltstone/shale of the transgressive system tract.

  2. Application of sequence stratigraphy to carbonate reservoir prediction, Early Palaeozoic eastern Warburton basin, South Australia

    SciTech Connect

    Xiaowen S.; Stuart, W.J.

    1996-12-31

    The Early Palaeozoic Warburton Basin underlies the gas and oil producing Cooper and Eromanga Basins. Postdepositional tectonism created high potential fracture porosities, complicating the stratigraphy and making reservoir prediction difficult. Sequence stratigraphy integrating core, cuttings, well-log, seismic and biostratigraphic data has recognized a carbonate-dominated to mixed carbonate/siliciclastic supersequence comprising several depositional sequences. Biostratigraphy based on trilobites and conodonts ensures reliable well and seismic correlations across structurally complex areas. Lithofacies interpretation indicates sedimentary environments ranging from carbonate inner shelf, peritidal, shelf edge, deep outer shelf and slope to basin. Log facies show gradually upward shallowing trends or abrupt changes indicating possible sequence boundaries. With essential depositional models and sequence analysis from well data, seismic facies suggest general reflection configurations including parallel-continuous layered patterns indicating uniform neuritic shelf, and mounded structures suggesting carbonate build-ups and pre-existing volcanic relief. Seismic stratigraphy also reveals inclined slope and onlapping margins of a possibly isolated platform geometry. The potential reservoirs are dolomitized carbonates containing oomoldic, vuggy, intercrystalline and fracture porosities in lowstand systems tracts either on carbonate mounds and shelf crests or below shelf edge. The source rock is a deep basinal argillaceous mudstone, and the seal is fine-grained siltstone/shale of the transgressive system tract.

  3. Subsurface geometry and growth history of the Warfield Structure in South-Central West Virginia, Central Appalachian basin

    SciTech Connect

    Gao, D.; Shumaker, R.C. )

    1994-08-01

    The Warfield structure is located at the eastern margin of Rome trough in south-central West Virginia, an intersection area between the 38th parallel and the Burning Springs lineaments in the central Appalachian basin. Using SURFACE III and MCS contouring packages, structure maps of upper Paleozoic horizons were completed by retrieving, editing, and contouring over 6000 shallow wells from the database of the DEAM (Data Editing and Management) software package. The Warfield anticline is horizontal at the Mississippian horizons, with a generally northeast-trending closure and a northwest-dipping axial plane, but at the Devonian level the closure is lost as the fold plunges northeastward. Structures from the Oriskany horizon to the basement were interpolated based on seismic and well data with a multisurface STACK procedure of the MCS package, and demonstrate a constrained half graben underneath the Warfield anticline with a 38th parallel and the north-south-trending Burning Springs lineaments. Based on preliminary results from subsurface mapping, digitization, and quantitative analysis of seismic time sections as well as computer modeling for the magnetic/gravity anomalies, the authors postulate that the geometry and growth history of the Warfield structure were genetically controlled by a wedge-shaped basement fault system in which the strike-slip displacement along both the eastwest-trending and the north-south-trending faults, and the dip-slip displacement on the northeast-trending faults occurred synchronously in response to the episodic movement of a wedge-shaped basement block bounded by the east-west-trending 38th parallel and the north-south-trending Burning Springs lineaments as well as the northeast-trending trough-margin faults throughout the Paleozoic.

  4. New Vitrinite Reflectance Data for the Bighorn Basin, North-Central Wyoming and South-Central Montana

    USGS Publications Warehouse

    Finn, Thomas M.; Pawlewicz, Mark J.

    2007-01-01

    Introduction The Bighorn Basin is a large Laramide (Late Cretaceous through Eocene) structural and sedimentary basin that encompasses about 10,400 mi2 in north-central Wyoming and south-central Montana (fig. 1). Important conventional oil and gas resources have been discovered and produced from reservoirs ranging in age from Cambrian through Tertiary (Fox and Dolton, 1989, 1996a, b; De Bruin, 1993). In addition, a potential unconventional basin-centered gas accumulation may be present in Cretaceous reservoirs (Johnson and Finn, 1998; Johnson and others, 1999). The purpose of this report is to present new vitrinite reflectance data to be used in support of the U.S Geological Survey's assessment of undiscovered oil and gas resources of the Bighorn Basin. These new data supplement previously published data by Nuccio and Finn (1998), and Yin (1997), and lead to a better understanding and characterization of the thermal maturation and burial history of potential source rocks. Eighty-nine samples of Cretaceous and Tertiary strata (fig. 2) were collected and analyzed - 15 samples were from outcrops around the margins of the basin and 74 samples were well cuttings (fig. 1). Forty-one of the samples were shale, two were carbonaceous shale, and the remainder from coal. All samples were analyzed by vitrinite reflectance to determine levels of thermal maturation. Preparation of samples for reflectance analysis required (1) crushing the larger pieces into 0.25-to 1-mm pieces, (2) casting the pieces with epoxy in pre-cut and drilled plugs, and (3) curing the samples overnight. Subsequently, a four-step grinding and polishing process was implemented that included sanding with progressively finer sandpaper (60 and 600 grit) followed with a two-step polishing process (0.3 and 0.05 micron). Vitrinite reflectance measurements were determined at 500 X magnification using plane-polarized incident white light and a 546-nm monochromatic filter in immersion oil. For samples containing

  5. Knowledge and Understanding of the Hydrogeology of the Salt Basin in South-Central New Mexico and Future Study Needs

    USGS Publications Warehouse

    Huff, G.F.; Chace, D.A.

    2006-01-01

    The Salt Basin covers about 2,400 square miles of south-central New Mexico and extends across the State line into Texas. As much as 57 million acre-feet of ground water may be stored within the New Mexico part of the Salt Basin of which 15 million acre-feet are potentially potable and recoverable. Recent work suggests that the volume of ground water in storage within the New Mexico portion of the Salt Basin may be substantially greater than 57 million acre-feet. In this report, aquifers contained in the San Andres, Bone Spring, and Victorio Peak Limestones and in the Yeso, Hueco, and Abo Formations are collectively referred to as the carbonate aquifer. Porosity and permeability of the major aquifer are primarily determined by the density and interconnectedness of fractures and karstic solution channels. The spatial variability of these fractures and karstic features leads to a large spatial variability in hydraulic properties in the carbonate aquifer. Ground water generally moves southward away from recharge areas along the northern border of the Salt Basin and generally moves eastward to southeastward away from areas of distributed recharge on the Otero Mesa and the Diablo Plateau. Ground water originating from these recharge areas generally moves toward the central valley. Present day discharge is mostly through ground-water withdrawal for agricultural irrigation. A zone of relatively low hydraulic gradient, corresponding to the location of the Otero Break, extends from near the Sacramento River watershed southward toward Dell City, Texas. Ground water in the carbonate aquifer generally is very hard and has dissolved-solids concentrations ranging from 500 to 6,500 milligrams per liter. Substantial variability exists in current estimates of (1) ground-water recharge, (2) natural ground-water discharge, (3) the volume of ground water in storage, (4) the volume of recoverable ground water, (5) the conceptual model of ground-water flow, (6) the distribution of ground

  6. Geophysical anomalies and quartz microstructures, Eastern Warburton Basin, North-east South Australia: Tectonic or impact shock metamorphic origin?

    NASA Astrophysics Data System (ADS)

    Glikson, Andrew Y.; Uysal, I. Tonguç; Fitz Gerald, John D.; Saygin, Erdinc

    2013-03-01

    The Eastern Warburton Basin, Northeast South Australia, features major geophysical anomalies, including a magnetic high of near-200 nT centred on a 25 km-wide magnetic low (< 100 nT), interpreted in terms of a magmatic body below 6 km depth. A distinct seismic tomographic low velocity anomaly may reflect its thick (9.5 km) sedimentary section, high temperatures and possible deep fracturing. Scanning electron microscope (SEM) analyses of granites resolves microbreccia veins consisting of micron-scale particles injected into resorbed quartz grains. Planar and sub-planar elements in quartz grains (Qz/PE) occur in granites, volcanics and sediments of the > 30,000 km-large Eastern Warburton Basin. The Qz/PE include multiple intersecting planar to curved sub-planar elements with relic lamellae less than 2 μm wide with spacing of 4-5 μm. Qz/PE are commonly re-deformed, displaying bent and wavy patterns accompanied with fluid inclusions. U-stage measurements of a total of 243 planar sets in 157 quartz grains indicate dominance of ∏{10-12}, ω{10-13} and subsidiary §{11-22}, {22-41}, m{10-11} and x{51-61} planes. Transmission Electron Microscopy (TEM) analysis displays relic narrow ≤ 1 μm-wide lamellae and relic non-sub grain boundaries where crystal segments maintain optical continuity. Extensive sericite alteration of feldspar suggests hydrothermal alteration to a depth of 500 m below the unconformity which overlies the Qz/PE-bearing Warburton Basin terrain. The data are discussed in terms of (A) Tectonic-metamorphic deformation and (B) impact shock metamorphism producing planar deformation features (Qz/PDF). Deformed Qz/PE are compared to re-deformed Qz/PDFs in the Sudbury, Vredefort, Manicouagan and Charlevoix impact structures. A 4-5 km uplift of the Big Lake Granite Suite during 298-295 Ma is consistent with missing of upper Ordovician to Devonian strata and possible impact rebound. The occurrence of circular seismic tomography anomalies below the east

  7. Detection and Extent of Ancient, Buried Mare Deposits in South Pole-Aitken Basin (SPA):Implications for Robotic Sampling

    NASA Astrophysics Data System (ADS)

    Petro, N. E.; Jolliff, B. L.; Gaddis, L. R.; Pieters, C. M.

    2010-12-01

    The origin of the large mafic anomaly associated with the interior of the South Pole-Aitken Basin has been inferred to be largely the result of iron-rich lower crustal/upper mantle material exposed at the surface and/or a combination of ancient mare basalts covered by younger crater/basin ejecta (cryptomare) interspersed with younger basalts [1-3]. However, the relative influence of either source is poorly constrained, due in part to the unknown abundance of cryptomare within SPA. Early geologic mapping of the interior of SPA identified several plains units, thought to represent basin ejecta deposits [4, 5]. Newer remotely sensed VIS-NIR wavelength data suggested the presence of more extensive deposits of ancient, buried basalts [2, 3, 6]. Mare basalts, when mantled by non-local, low-FeO material may appear to be non-mare plains units [7, 8]. Within SPA, because the regional basement material is inherently enriched in FeO, the mantling material imparts a dark, FeO-enriched, signature. In a survey of rock types within SPA, Pieters et al. [3] identified such a plains unit south of the Apollo Basin with a surface that is both dark and that contains an FeO-rich spectral signature. However, several small craters in the plains unit expose underlying basaltic materials or cryptomaria in this extensive (>75,000 km2), ancient (~3.89 Ga) unit [6, 9]. The positive identification and characterization of cryptomaria within SPA are facilitated by high-spatial and spectral resolution data from recent orbital missions (e.g., Kaguya, Chandrayaan-1, LRO). Hyperspectral data from the Moon Mineralogy Mapper and Multiband Imager for SPA show the presence of two primary mafic materials; a high-Ca pyroxene (gabbroic) signature is pervasive across the center of the basin and a noritic signature is present across the rest of SPA. High spatial resolution (10-0.5 m) images from the Kaguya Terrain Camera and LRO Narrow Angle Camera facilitate surface age dating and morphologic assessment of

  8. Physical characteristics of stream subbasins in the Middle Minnesota - Little Cottonwood River Basin, south-central Minnesota

    USGS Publications Warehouse

    Sanocki, Christopher A.

    1997-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Middle Minnesota-Little Cottonwood River Basin, located in south-central Minnesota are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  9. Physical characteristics of stream subbasins in the Lac qui Parle River basin, southwestern Minnesota and eastern South Dakota

    USGS Publications Warehouse

    Lorenz, D.L.; Sanocki, C.A.; Winterstein, Thomas A.

    1994-01-01

    Data describing the physical characteristics of stream subbasins upstream from selected points on streams in the Lac qui Parle River basin, located in southwestern Minnesota and eastern South Dakota, are presented in this report. The physical charac- teristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length. and the main-channel slope. The points on the stream include outlets of subbasins of at least 5 square miles, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  10. Ecological data collected in the Santee River basin and coastal drainages, North and South Carolina, 1996-98

    USGS Publications Warehouse

    Abrahamsen, Thomas A.

    2001-01-01

    As part of the National Water-Quality Assessment Program, ecological investigations were conducted in 23 reaches of 16 streams in the Santee River Basin and Coastal Drainages study unit in North and South Carolina during 1996-98. Habitat characteristics, such as stream width and depth, bank composition, bank vegetative cover, stream shading by overhanging vegetation, and streambed composition were recorded. Algal and benthic invertebrate communities were sampled using quantitative and qualitative techniques. These data will provide information needed to: (1) support findings of the effects of human landuse activities on water quality by augmenting or enhancing physical and chemical water-quality data, (2) provide a basic overview of aquatic community structure in selected stream reaches in the study unit, and (3) provide a means for comparing aquatic communities in subsequent years of the assessment program.

  11. Physical characteristics of stream subbasins in the Hawk Creek-Yellow Medicine River basin, southwestern Minnesota and eastern South Dakota

    USGS Publications Warehouse

    Sanocki, Christopher A.

    1996-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Hawk Creek-Yellow Medicine River Basin, located in southwestern Minnesota and eastern South Dakota are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, outlets of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  12. Geohydrology of the Aucilla-Suwannee-Ochlockonee River Basin, south-central Georgia and adjacent parts of Florida

    USGS Publications Warehouse

    Torak, Lynn J.; Painter, Jaime A.; Peck, Michael F.

    2010-01-01

    Major streams and tributaries located in the Aucilla-Suwannee-Ochlockonee (ASO) River Basin of south-central Georgia and adjacent parts of Florida drain about 8,000 square miles of a layered sequence of clastic and carbonate sediments and carbonate Coastal Plain sediments consisting of the surficial aquifer system, upper semiconfining unit, Upper Floridan aquifer, and lower confining unit. Streams either flow directly on late-middle Eocene to Oligocene karst limestone or carve a dendritic drainage pattern into overlying Miocene to Holocene sand, silt, and clay, facilitating water exchange and hydraulic connection with geohydrologic units. Geologic structures operating in the ASO River Basin through time control sedimentation and influence geohydrology and water exchange between geohydrologic units and surface water. More than 300 feet (ft) of clastic sediments overlie the Upper Floridan aquifer in the Gulf Trough-Apalachicola Embayment, a broad area extending from the southwest to the northeast through the center of the basin. These clastic sediments limit hydraulic connection and water exchange between the Upper Floridan aquifer, the surficial aquifer system, and surface water. Accumulation of more than 350 ft of low-permeability sediments in the Southeast Georgia Embayment and Suwannee Strait hydraulically isolates the Upper Floridan aquifer from land-surface hydrologic processes in the Okefenokee Basin physiographic district. Burial of limestone beneath thick clastic overburden in these areas virtually eliminates karst processes, resulting in low aquifer hydraulic conductivity and storage coefficient despite an aquifer thickness of more than 900 ft. Conversely, uplift and faulting associated with regional tectonics and the northern extension of the Peninsular Arch caused thinning and erosion of clastic sediments overlying the Upper Floridan aquifer southeast of the Gulf Trough-Apalachicola Embayment near the Florida-Georgia State line. Limestone dissolution in

  13. Causality analysis of groundwater dynamics based on a Vector Autoregressive model in the semi-arid basin of Gundal (South India)

    NASA Astrophysics Data System (ADS)

    Mangiarotti, S.; Sekhar, M.; Berthon, L.; Javeed, Y.; Mazzega, P.

    2012-08-01

    Causal relationships existing between observed levels of groundwater in a semi-arid sub-basin of the Kabini River basin (Karnataka state, India) are investigated in this study. A Vector Auto Regressive model is used for this purpose. Its structure is built on an upstream/downstream interaction network based on observed hydro-physical properties. Exogenous climatic forcing is used as an input based on cumulated rainfall departure. Optimal models are obtained thanks to a trial approach and are used as a proxy of the dynamics to derive causal networks. It appears to be an interesting tool for analysing the causal relationships existing inside the basin. The causal network reveals 3 main regions: the Northeastern part of the Gundal basin is closely coupled to the outlet dynamics. The Northwestern part is mainly controlled by the climatic forcing and only marginally linked to the outlet dynamic. Finally, the upper part of the basin plays as a forcing rather than a coupling with the lower part of the basin allowing for a separate analysis of this local behaviour. The analysis also reveals differential time scales at work inside the basin when comparing upstream oriented with downstream oriented causalities. In the upper part of the basin, time delays are close to 2 months in the upward direction and lower than 1 month in the downward direction. These time scales are likely to be good indicators of the hydraulic response time of the basin which is a parameter usually difficult to estimate practically. This suggests that, at the sub-basin scale, intra-annual time scales would be more relevant scales for analysing or modelling tropical basin dynamics in hard rock (granitic and gneissic) aquifers ubiquitous in south India.

  14. Surface water of Beaver Creek Basin, in South-Central Oklahoma

    USGS Publications Warehouse

    Laine, L.L.; Murphy, J.J.

    1962-01-01

    Annual discharge from Beaver Creek basin is estimated to have averaged 217,000 acre-feet during a 19-year base period, water years 1938-56, equivalent to an average annual runoff depth of 4.7 inches over the 857 square-mile drainage area. About 55,000 acre-feet per year comes from Little Beaver Creek basin, a tributary drainage of 195 square miles. Yearly streamflow is highly variable. The discharge of Little Beaver Creek near Duncan during 13-year period of record (water years 1949-61) has ranged from 86,530 acre-feet in calendar year 1957 to 4,880 acre-feet in 1956, a ratio of almost 18 to 1. Highest runoff within a year tends to occur in the spring months of May and June, a 2-month period that, on the average, accounts for more than half of the annual discharge of Little Beaver Creek near Duncan. The average monthly runoff during record was lowest in January. Variation in daily streamflow is such that while the average discharge for the 13-year period of record was 50.1 cfs (cubic feet per second), the daily discharge was more than 6 cfs only about half of the time. There was no flow at the site 19 percent of the time during the period. Some base runoff usually exists in the headwaters of Beaver and Little Beaver Creeks, and in the lower reaches of Beaver Creek. Low flow in Cow Creek tends to be sustained by waste water from Duncan, where water use in 1961 averaged 4 million gallons per day. In the remainder of the basin, periods of no flow occur in most years. The surface water of Beaver Creek basin is very hard but in general is usable for municipal, agricultural and industrial purposes. The chemical character of the water is predominantly a calcium, magnesium bicarbonate type of water in the lower three quarters of the basin, except in Cow Creek where oil-field brines induce a distinct sodium, calcium chloride characteristic at low and medium flows. A calcium sulfate type of water occurs in most of the northern part of the basin except in headwater areas

  15. Land-Use Change Impacts on Intensity, Duration, and Frequency of Precipitation in the South Platte River Basin

    NASA Astrophysics Data System (ADS)

    Pina, A.; Denning, A. S.

    2014-12-01

    The Westward Expansion of the mid-1800s directly impacted the distribution of moisture in the South Platte River Basin (SPRB) by changing land surfaces from natural rangelands, grasslands, and shrublands to a disturbed state of urbanized cities, livestock pastures, and irrigated croplands. Changing land surfaces repartitions latent and sensible energy surface fluxes and inadvertently results in changes to the regional climate. In this study, we examined the impacts of land-use change on the meteorology and climate in the South Platte River Basin, a region sensitive to water-use management. WRF-ARW v3.4.1 was used to downscale the reanalysis of a climatologically normal summer (2010) to 0.5 km horizontal resolution over the SPRB. To analyze meteorological and climatological effects of land-use changes in northeastern Colorado, a control run where no changes to the input data was compared with a run which changed land-use index from anthropogenic-influenced landscapes back to their original vegetative land cover. Notable changes in the Bowen ratio around urban and irrigated lands as well as an enhancement of the mountain-valley circulation east of the Rocky Mountains were observed due to land-use changes. Output from the control run of the WRF simulation were used as a baseline for running a simulation to 2100 using a newly-developed multi-scale modeling framework based on the Community Earth System Model, which explicitly resolves convection in global climate model grid cells. Results of changing IDF curves over the 21st century can be compared with results shown in national and international documents such as the National Climate Assessment and Intergovernmental Panel on Climate Change reports and used as planning tools for optimizing the balance of water management between agriculture communities and municipalities in Colorado.

  16. Surface water of Muddy Boggy River basin in south-central Oklahoma

    USGS Publications Warehouse

    Westfall, A.O.; Cummings, T. Ray

    1963-01-01

    This report summarizes basic hydrologic data of the surface water resources of Muddy Boggy River basin, and by analysis and interpretation, presents certain streamflow characteristics at specified points in the basin. Muddy Boggy River has a drainage area of 2,429 square miles. The climate is moist subhumid and the annual precipitation averages about 39 inches. Gross annual lake evaporation averages 54 inches. The average annual discharge at the gaging stations for the period 1938-62 was 24,000 acre-feet for Chickasaw Creek near Stringtown; 72,000 acre-feet for McGee Creek near Stringtown; 671,800 acre-feet for Muddy Boggy Creek near Farris; and 358,200 acre-feet for Clear Boggy Creek near Caney. Flow-duration curves of daily discharge have been developed to show the percentage of time various rates of discharge have been equaled or exceeded. Procedures for determining the frequency of annual floods at any point in the basin are given. Low-flow frequency curves that define the recurrence intervals of 7, 14, 30, 60, and 120 day mean flows have been prepared for two gaging stations. Curves showing the relation of measured discharge at the low-flow partial-record stations to the daily mean discharge at a base gaging station are presented. Discharge measurements made in February 1963 at selected sites show the areal distribution of low flow. The storage requirements to supplement natural flows have been prepared for two gaging-stations sites. The chemical quality of surface water of Muddy Boggy River basin varies from place-to-place during base flow periods. Limestone and dolomite outcrops and oilfield brines affect water quality in some areas. Water of North Boggy Creek, McGee Creek, and their tributaries contains less than 100 ppm (parts per million) dissolved solids. Water of other streams in Muddy Boggy River basin has a higher dissolved-solids content, but the content does not exceed 500 ppm. Water of Muddy Boggy River basin is usable for domestic, irrigation, and

  17. Landscape Level Carbon and Water Balances and Agricultural Production in Mountainous Terrain of the Haean Basin, South Korea

    NASA Astrophysics Data System (ADS)

    Lee, B.; Geyer, R.; Seo, B.; Lindner, S.; Walther, G.; Tenhunen, J. D.

    2009-12-01

    The process-based spatial simulation model PIXGRO was used to estimate gross primary production, ecosystem respiration, net ecosystem CO2 exchange and water use by forest and crop fields of Haean Basin, South Korea at landscape scale. Simulations are run for individual years from early spring to late fall, providing estimates for dry land crops and rice paddies with respect to carbon gain, biomass and leaf area development, allocation of photoproducts to the belowground ecosystem compartment, and harvest yields. In the case of deciduous oak forests, gas exchange is estimated, but spatial simulation of growth over the single annual cycles is not included. Spatial parameterization of the model is derived for forest LAI based on remote sensing, for forest and cropland fluxes via eddy covariance and chamber studies, for soil characteristics by generalization from spatial surveys, for climate drivers by generalizing observations at ca. 20 monitoring stations distributed throughout the basin and along the elevation gradient from 500 to 1000 m, and for incident radiation via modelling of the radiation components in complex terrain. Validation of the model is being carried out at point scale based on comparison of model output at selected locations with observations as well as with known trends in ecosystem response documented in the literature. The resulting modelling tool is useful for estimation of ecosystem services at landscape scale, first expressed as kg ha-1 crop yield, but via future cooperative studies also in terms of monetary gain to individual farms and farming cooperatives applying particular management strategies.

  18. Clay mineralogical evidence of a bioclimatically-affected soil, Rouge River basin, South-Central Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Mahaney, W. C.

    2015-01-01

    Holocene soils in drainage basins of South-Central Ontario, Canada, are generally Fluvisols (Entisols) in floodplains transitioning to Brunisols (Inceptisols), Luvisols (Alfisols) and Podzols (Spodosols) in older terraces and in the glaciated tableland. A single landslide sourced from the highest fluvial terrace in the Rouge basin, with a rubble drop of ~ 12 m emplaced a lobe-shaped mass of reworked stream gravel, glaciolacustrine sediment and till, emplaced approximately 6 m above mean water level at a height roughly equivalent to previously dated mid-Holocene terraces and soils. Clay mineralogy of the soil formed in this transported regolith produced the usual semi-detrital/pedogenic distribution of 1:1 (Si:Al = 1:1), 2:1 and 2:1:1 clay minerals as well as primary minerals consisting of plagioclase feldspar, quartz, mica and calcite. Unexpectedly, the presence of moderate amounts of Ca-smectite in the Bk and Ck horizons, relative to a clay-mineral depleted parent material (Cuk), argues for a soil hydrological change affecting the wetting depth in the deposit. The presence of the uncommon 'maidenhair fern' (Adiantum pedantum) in the mass wasted deposit, a plant capable of high evapotranspiration, is interpreted as producing a bioclimatic disruption limiting soil water penetration to near root depth (wetting depth), thus producing a clay mineral anomaly.

  19. The coal-forming plants of the upper part of the Lower Cretaceous Starosuchan Formation (Partizansk Basin, South Primorye region)

    NASA Astrophysics Data System (ADS)

    Bugdaeva, E. V.; Markevich, V. S.; Volynets, E. B.

    2014-05-01

    The plant remains and palynological assemblages are studied in detail in the section of the coal-bearing upper part of the Aptian Starosuchan Formation near the village of Molchanovka (Partizansk Basin, South Primorye region). On the basis of the light and electron microscopic study of the disperse cuticles, it was established that the coals are mostly composed of remains of taxodialean Elatides asiatica (Yok.) Krassil., subordinate Miroviaceae, rare ginkgoalean Pseudotorellia sp., and bennettite Nilssoniopteris rithidorachis (Krysht.) Krassil. The spores Gleicheniidites and pollen Taxodiaceaepollenites are dominant in the palynospectrum of the coal interlayer. It was found that dominant taxodialeans and gleicheniaceous ferns with less abundant Miroviaceae, ginkgoaleans, and rare bennettites occurred in the Aptian swamp communities of the Partizansk basin. Shoots and leaves of Elatides asiatica, fronds of Birisia onychioides (Vassil. et K.-M.) Samyl., are dominant in the burials of plants from the clastic rocks. The fragments of leaves of Nilssoniopteris, scale-leaved conifers, and Ginkgo ex gr. adiantoides are rare. The disperse cuticle of these layers mostly includes Pseudotorellia sp.; however, its remains in burials were not found. The spores Laevigatosporites are dominant in the palynospectra from the clastic interlayers. Ginkgocycadophytus and taxa close to Pinaceae are plentiful among the pollen of gymnosperms.

  20. The formation of the South Tharsis Ridge Belt: Basin and Range-style extension on early Mars?

    NASA Astrophysics Data System (ADS)

    Karasözen, Ezgi; Andrews-Hanna, Jeffrey C.; Dohm, J. M.; Anderson, R. C.

    2016-06-01

    The South Tharsis Ridge Belt (STRB) is located along the northeastern edge of Terra Sirenum and partially surrounds the southwestern part of Tharsis in an arc. It consists of 29 large ridges separated by distances 130 to 260 km, with average relief of 1.5 km above the surrounding plains. Because the STRB is among the oldest tectonic features associated both spatially and developmentally with Tharsis, it may provide key information on the early evolution of Tharsis and possibly pre-Tharsis processes. Earlier studies concluded that the ridges formed through compressional tectonism. However, the shape, size, and separation of the ridges support the interpretation that the STRB resembles the extensional Basin and Range Province on Earth. Both regions are characterized by series of parallel mountain ranges separated by broad valleys. In this study, we evaluate both extensional and compressional hypotheses for the origin of the ridges using evidence from topography, deformed craters, crustal thickness models, and strain modeling. Though neither interpretation explains all aspects of the ridges, the topography of the ridges and crustal thinning associated with the western part of the ridge belt support an extensional origin. Strain models predict that Basin and Range-style wide rifting would be expected for early Martian conditions. This extension may have been initiated by plume-induced uplift in the early stages of Tharsis formation, but the large amount of extensional strain inferred in the western STRB must have been accommodated by compression elsewhere, possibly in the heavily deformed craters of western Terra Sirenum.

  1. Hydrogeochemistry and groundwater quality assessment of lower part of the Ponnaiyar River Basin, Cuddalore district, South India.

    PubMed

    Jeevanandam, M; Kannan, R; Srinivasalu, S; Rammohan, V

    2007-09-01

    The Lower Ponnaiyar River Basin forms an important groundwater province in South India constituted by Tertiary formations dominated by sandstones and overlain by alluvium. The region enjoyed artesian conditions 50 years back but at present frequent failure of monsoon and over exploitation is threatening the aquifer. Further, extensive agricultural and industrial activities and urbanization has resulted in the increase in demand and contamination of the aquifer. To identify the sources and quality of groundwater, water samples from 47 bore wells were collected in an area of 154 km2 and were analysed for major ions and trace metals. The results reveal that the groundwater in many places is contaminated by higher concentrations of NO3, Cl, PO4 and Fe. Four major hydrochemical facies Ca-Mg-Cl, Na-Cl, Ca-HCO3 and Na-HCO3 were identified using Piper trilinear diagram. Salinity, sodium adsorption ratio, and sodium percentage indicate that most of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standards. The most serious pollution threat to groundwater is from nitrate ions, which are associated with sewage and fertilizers application. The present state of the quality of the lower part of Ponnaiyar River Basin is of great concern and the higher concentration of toxic metals (Fe and Ni) may entail various health hazards.

  2. Flood-tracking chart for the Withlacoochee and Little River Basins in south-central Georgia and northern Florida

    USGS Publications Warehouse

    Gotvald, Anthony J.; McCallum, Brian E.; Painter, Jaime A.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with other Federal, State, and local agencies, operates a flood-monitoring system in the Withlacoochee and Little River Basins. This system is a network of automated river stage stations (ten are shown on page 2 of this publication) that transmit stage data through satellite telemetry to the USGS in Atlanta, Georgia and the National Weather Service (NWS) in Peachtree City, Georgia. During floods, the public and emergency response agencies use this information to make decisions about road closures, evacuations, and other public safety issues. This Withlacoochee and Little River Basins flood-tracking chart can be used by local citizens and emergency response personnel to record the latest river stage and predicted flood-crest information along the Withlacoochee River, Little River, and Okapilco Creek in south-central Georgia and northern Florida. By comparing the current stage (water-surface level above a datum) and predicted flood crest to the recorded peak stages of previous floods, emergency response personnel and residents can make informed decisions concerning the threat to life and property.

  3. Characterization of gas hydrate distribution using conventional 3D seismic data in the Pearl River Mouth Basin, South China Sea

    USGS Publications Warehouse

    Wang, Xiujuan; Qiang, Jin; Collett, Timothy S.; Shi, Hesheng; Yang, Shengxiong; Yan, Chengzhi; Li, Yuanping; Wang, Zhenzhen; Chen, Duanxin

    2016-01-01

    A new 3D seismic reflection data volume acquired in 2012 has allowed for the detailed mapping and characterization of gas hydrate distribution in the Pearl River Mouth Basin in the South China Sea. Previous studies of core and logging data showed that gas hydrate occurrence at high concentrations is controlled by the presence of relatively coarse-grained sediment and the upward migration of thermogenic gas from the deeper sediment section into the overlying gas hydrate stability zone (BGHSZ); however, the spatial distribution of the gas hydrate remains poorly defined. We used a constrained sparse spike inversion technique to generate acoustic-impedance images of the hydrate-bearing sedimentary section from the newly acquired 3D seismic data volume. High-amplitude reflections just above the bottom-simulating reflectors (BSRs) were interpreted to be associated with the accumulation of gas hydrate with elevated saturations. Enhanced seismic reflections below the BSRs were interpreted to indicate the presence of free gas. The base of the BGHSZ was established using the occurrence of BSRs. In areas absent of well-developed BSRs, the BGHSZ was calculated from a model using the inverted P-wave velocity and subsurface temperature data. Seismic attributes were also extracted along the BGHSZ that indicate variations reservoir properties and inferred hydrocarbon accumulations at each site. Gas hydrate saturations estimated from the inversion of acoustic impedance of conventional 3D seismic data, along with well-log-derived rock-physics models were also used to estimate gas hydrate saturations. Our analysis determined that the gas hydrate petroleum system varies significantly across the Pearl River Mouth Basin and that variability in sedimentary properties as a product of depositional processes and the upward migration of gas from deeper thermogenic sources control the distribution of gas hydrates in this basin.

  4. Thermal evolution, fluid flow, and fracture development related to the structuration of the South Pyrenean Foreland Basin

    NASA Astrophysics Data System (ADS)

    Crognier, N.; Hoareau, G.; Aubourg, C.; Branellec, M.; Dubois, M.; Lahfid, A.; Lacroix, B.; Labaume, P.; Suarez-Ruiz, I.

    2015-12-01

    The E-W trending South Pyrenean Foreland Basin, formed during the upper Cretaceous and the early Miocene due to the collision between Iberian and European plates, is filled by marine to continental deposits affected by a set of successive southvergent thrusts. In order to constrain the links between fracture development, thermal regime, and fluid flow in the basin, we estimated temperatures of formation and C-O isotope signatures of fracture-filling minerals (veins), maximum paleo-temperatures of sediments, and the timing and orientation of major fracture sets. The isotopic composition of 150 veins and sediment samples has been measured. Peak temperatures of 100 bulk rocks and veins have been estimated, using Raman spectroscopy, vitrinite reflectance, fluid inclusion microthermometry and mass-47 clumped isotopes. The orientation of ~5000 joints and veins has been used to link major tectonic events to fracture development. Most primary fluid inclusions show moderate salinities (~2.5 wt%), compatible with connate or evolved meteoric waters. Fluids were generally in thermal and isotopic equilibrium with host sediments, suggesting a low fluid-rock ratio, and thus a limited impact of fractures on fluid-flow. Peak temperatures (T max) decrease southward, from ~240°C in Cretaceous to Eocene sediments close to the axial zone, to ~60°C. In a same location dominant compaction joints were mineralized close to T max, ~40°C higher than tectonic shear veins. All fracture orientations were likely controlled by Pyrenean shortening. Genetic relationships between fracture sets are currently under investigation. Finally, temperatures of 240°C measured in Eocene sediments cannot be explained by balanced cross sections using geothermal gradient expected in foreland basins (20-25°C/km). 1D thermal modeling is being performed to explain this thermal anomaly, which could result from high heat flow following mid-Cretaceous extension, the ingress of hot fluids, or undocumented tectonic

  5. Comparison of Methylmercury Production and Accumulation in Sediments of the Congaree and Edisto River Basins, South Carolina, 2004-06

    USGS Publications Warehouse

    Bradley, Paul M.; Chapelle, Francis H.; Journey, Celeste A.

    2009-01-01

    Fish-tissue mercury concentrations (approximately 2 micrograms per gram) in the Edisto River basin of South Carolina are among the highest recorded in the United States. Substantially lower mercury concentrations (approximately 0.2 microgram per gram) are reported in fish from the adjacent (about 30 kilometer) Congaree River basin and the Congaree National Park. In contrast, concentrations of total mercury were statistically higher in sediments from the Congaree River compared with those in sediments from the Edisto River. Furthermore, no statistically significant difference was observed in concentrations of methylmercury or net methylation potential in sediments collected from various Edisto and Congaree hydrologic settings. In both systems, the net methylation potential was low (0-0.17 nanogram per gram per day) for in-stream sediments exposed to continuously flowing water but substantially higher (about 1.8 nanograms per gram per day) in wetland sediments exposed to standing water. These results are not consistent with the hypothesis that differences in fish-tissue mercury between the Edisto and Congaree basins reflect fundamental differences in the potential for each system to methylate mercury. Rather, the significantly higher ratios of methylmercury to total mercury observed in the Edisto system suggest that the net accumulation and(or) preservation of methylmercury are greater in the Edisto system. The marked differences in net methylation potential observed between the wetland and in-stream settings suggest the hypothesis that methylmercury transport from zones of production (wetlands) to points of entry into the food chain (channels) may contribute to the observed differences in fish-tissue mercury concentrations between the two river systems.

  6. Tectonic significance of porosity and permeability regimes in the red beds formations of the South Georgia Rift Basin

    NASA Astrophysics Data System (ADS)

    Akintunde, Olusoga M.; Knapp, Camelia C.; Knapp, James H.

    2014-09-01

    A simple, new porosity/permeability-depth profile was developed from available laboratory measurements on Triassic sedimentary red beds (sandstone) from parts of the South Georgia Rift (SGR) basin in order to investigate the feasibility for long-term CO2 storage. The study locations were: Sumter, Berkeley, Dunbarton, Clubhouse Crossroad-3 (CC-3) and Norris Lightsey wells. As expected, both porosity and permeability show changes with depth at the regional scale that was much greater than at local scale. The significant changes in porosity and permeability with depth suggest a highly compacted, deformed basin, and potentially, a history of uplift and erosion. The permeability is generally low both at shallow (less than 1826 ft/556.56 m) and deeper depths (greater than 1826 ft/556.56 m). Both porosity and permeability follow the normal trend, decreasing linearly with depth for most parts of the study locations with the exception of the Norris Lightsey well. A petrophysical study on a suite of well logs penetrating the Norris Lightsey red beds at depths sampled by the core-derived laboratory measurements shows an abnormal shift (by 50%) in the acoustic travel time and/or in the sonic-derived P-wave velocity that indicates possible faulting or fracturing at depth. The departure of the Norris Lightsey's porosities and permeabilities from the normal compaction trend may be a consequence of the existence of a fault/fracture controlled abnormal pressure condition at depth. The linear and non-linear behaviors of the porosity/permeability distribution throughout the basin imply the composition of the SGR red beds, and by extension analog/similar Triassic-Jurassic formations within the Eastern North American Margin have been altered by compaction, uplift, erosion and possible faulting that have shaped the evolution of these Triassic formations following the major phase of rifting.

  7. Physical stratigraphy and sedimentology of an alluvial fan delta complex (south Pyrenean basin, Spain)

    SciTech Connect

    Crumeyrolle, P.

    1988-08-01

    The Santa Liestra is comprised of four main stratigraphic units with a major stratigraphic unconformity separating unit 2 from unit 3. This unconformity is expressed by an abrupt facies change and large-scale shelf instability features, and it probably represents a depositional sequence boundary related to a phase of thrust movement within the Santa Liestra sequence. Field correlations on transverse cross sections through the basin show a typical foreland asymmetrical clastic wedge; these correlations also illustrate the sheet-like geometry of the fan delta-front deposits. This study of a large fan delta-front system furnishes insight into the complex interactions governing the geometry and sedimentological characteristics of potential petroleum reservoirs in foreland basin settings.

  8. Computation of groundwater resources and recharge in Chithar River Basin, South India.

    PubMed

    Subramani, T; Babu, Savithri; Elango, L

    2013-01-01

    Groundwater recharge and available groundwater resources in Chithar River basin, Tamil Nadu, India spread over an area of 1,722 km(2) have been estimated by considering various hydrological, geological, and hydrogeological parameters, such as rainfall infiltration, drainage, geomorphic units, land use, rock types, depth of weathered and fractured zones, nature of soil, water level fluctuation, saturated thickness of aquifer, and groundwater abstraction. The digital ground elevation models indicate that the regional slope of the basin is towards east. The Proterozoic (Post-Archaean) basement of the study area consists of quartzite, calc-granulite, crystalline limestone, charnockite, and biotite gneiss with or without garnet. Three major soil types were identified namely, black cotton, deep red, and red sandy soils. The rainfall intensity gradually decreases from west to east. Groundwater occurs under water table conditions in the weathered zone and fluctuates between 0 and 25 m. The water table gains maximum during January after northeast monsoon and attains low during October. Groundwater abstraction for domestic/stock and irrigational needs in Chithar River basin has been estimated as 148.84 MCM (million m(3)). Groundwater recharge due to monsoon rainfall infiltration has been estimated as 170.05 MCM based on the water level rise during monsoon period. It is also estimated as 173.9 MCM using rainfall infiltration factor. An amount of 53.8 MCM of water is contributed to groundwater from surface water bodies. Recharge of groundwater due to return flow from irrigation has been computed as 147.6 MCM. The static groundwater reserve in Chithar River basin is estimated as 466.66 MCM and the dynamic reserve is about 187.7 MCM. In the present scenario, the aquifer is under safe condition for extraction of groundwater for domestic and irrigation purposes. If the existing water bodies are maintained properly, the extraction rate can be increased in future about 10% to 15%.

  9. GIS/RS-based Integrated Eco-hydrologic Modeling in the East River Basin, South China

    NASA Astrophysics Data System (ADS)

    Wang, Kai

    Land use/cover change (LUCC) has significantly altered the hydrologic system in the East River (Dongjiang) Basin. Quantitative modeling of hydrologic impacts of LUCC is of great importance for water supply, drought monitoring and integrated water resources management. An integrated eco-hydrologic modeling system of Distributed Monthly Water Balance Model (DMWBM), Surface Energy Balance System (SEBS) was developed with aid of GIS/RS to quantify LUCC, to conduct physically-based ET (evapotranspiration) mapping and to predict hydrologic impacts of LUCC. To begin with, in order to evaluate LUCC, understand implications of LUCC and provide boundary condition for the integrated eco-hydrologic modeling, firstly the long-term vegetation dynamics was investigated based on Normalized Difference Vegetation Index (NDVI) data, and then LUCC was analyzed with post-classification methods and finally LUCC prediction was conducted based on Markov chain model. The results demonstrate that the vegetation activities decreased significantly in summer over the years. Moreover, there were significant changes in land use/cover over the past two decades. Particularly there was a sharp increase of urban and built-up area and a significant decrease of grassland and cropland. All these indicate that human activities are intensive in the East River Basin and provide valuable information for constructing scenarios for studying hydrologic impacts of LUCC. The physically-remote-sensing-based Surface Energy Balance System (SEBS) was employed to estimate areal actual ET for a large area rather than traditional point measurements . The SEBS was enhanced for application in complex vegetated area. Then the inter-comparison with complimentary ET model and distributed monthly water balance model was made to validate the enhanced SEBS (ESEBS). The application and test of ESEBS show that it has a good accuracy both monthly and annually and can be effectively applied in the East River Basin. The results of

  10. Distribution of organic carbon and petroleum source rock potential of Cretaceous and lower Tertiary carbonates, South Florida Basin: preliminary results

    USGS Publications Warehouse

    Palacas, James George

    1978-01-01

    Analyses of 134 core samples from the South Florida Basin show that the carbonates of Comanchean age are relatively richer in average organic carbon (0.41 percent) than those of Coahuilan age (0.28 percent), Gulfian age (0.18 percent) and Paleocene age (0.20 percent). They are also nearly twice as rich as the average world, wide carbonate (average 0.24 percent). The majority of carbonates have organic carbons less than 0.30 percent but the presence of many relatively organic rich beds composed of highly bituminous, argillaceous, highly stylolitic, and algal-bearing limestones and dolomites accounts for the higher percentage of organic carbon in some of the stratigraphic units. Carbonate rocks that contain greater than 0.4 percent organic carbon and that might be considered as possible petroleum sources were noted in almost each subdivision of the Coahuilan and Comanchean Series but particularly the units of Fredericksburg 'B', Trinity 'A', Trinity 'F', and Upper Sunniland. Possible source rocks have been ascribed by others to the Lower Sunniland, but lack of sufficient samples precluded any firm assessment in this initial report. In the shallower section of the basin, organic-rich carbonates containing as much as 3.2 percent organic carbon were observed in the lowermost part of the Gulfian Series and carbonate rocks with oil staining or 'dead' and 'live oil' were noted by others in the uppermost Gulfian and upper Cedar Keys Formation. It is questionable whether these shallower rocks are of sufficient thermal maturity to have generated commercial oil. The South Florida basin is still sparsely drilled and produces only from the Sunniland Limestone at an average depth of 11,500 feet (3500 m). Because the Sunniland contains good reservoir rocks and apparently adequate source rocks, and because the success rate of new oil field discoveries has increased in recent years, the chances of finding additional oil reserves in the Sunniland are promising. Furthermore, the

  11. Ectoparasites in black-footed ferrets (Mustela nigripes) from the largest reintroduced population of the Conata Basin, South Dakota, USA.

    PubMed

    Harris, Nyeema C; Livieri, Travis M; Dunn, Robert R

    2014-04-01

    The black-footed ferret, Mustela nigripes, is an endangered carnivore endemic to the grasslands of North America. We present the first investigation of ectoparasites associated with black-footed ferrets since reintroduction. We sampled more than 200 individuals from one of the largest and most successful reintroduced populations located in the Conata Basin of South Dakota, USA. We compared our findings with ectoparasite assemblages of sympatric carnivores and historic ferret records. We collected more than 1,000 ectoparasites consisting mainly of three flea and tick species, two of which were known historically from South Dakota. Despite our extensive sampling efforts, we did not detect any lice. This is notable because a putative host-specific louse, Neotrichodectes sp., was presumed to have gone extinct when black-footed ferrets were extirpated from the wild. The ectoparasite assemblage on black-footed ferrets comprised only generalist parasites, particularly those found on their prey such as prairie dogs (Cynomys sp.). Oropsylla hirsuta was the most abundant ectoparasite, representing 57% of all ectoparasites detected; a flea vector important in the persistence and transmission of plague. Black-footed ferrets like other endangered species undergo repeated parasite removal and vaccination efforts to facilitate population recovery, which may have unintentionally contributed to their depauperate ectoparasite community. PMID:24499333

  12. EFFECTS OF HABITAT DEGRADATION ON BIOLOGICAL ENDPOINTS IN THE SOUTH FORK BROAD RIVER BASIN, GEORGIA

    EPA Science Inventory

    Many of the streams of the lower Piedmont ecoregion in Georgia have been negatively impacted to some degree by habitat degradation due primarily to sedimentation. The South Fork of the Broad River watershed has been designated as sediment impacted under Section 303(d) of the Clea...

  13. Seismic interpretation and Structural analysis of a pull-apart basin: El Hamma grabens system (Gabes area, South of Tunisia)

    NASA Astrophysics Data System (ADS)

    Houssin, Mouna; Abbes, Chedly; bouzid, wajih

    2015-04-01

    The graben system of El Hamma, west of Gabes in Tunisia, represents an extensive relay ramp between two Principal Shear Zones (PSZ) with dextral N 120 sliding. These PSZ corresponds to two segments of the south-Atlasic shear corridor, which extends from Chott Hodna in Algeria, in the NW, to the Libyan Djeferra in SE. This extensive zone considered as a pull-apart basin, containing two grabens 40 Km long and 15 Km wide, each separated by a horst structure 4 Km large. Stratigraphic and structural analysis of the field outcrops, correlated with the tectonic events reconstitutions and paleostress showed two main phases in the structuring of this basin: - In Upper Turonian, under a regional N80 extensive stress, the PSZ were re-mobilized in dextral transtensional displacement inducing the opening of the graben system by extension of the relay zone. - The NW-SE shortening, installed since Tortonian, re-mobilize the PSZ in dextral transpressive displacement, further reactivating the opening of the basin. In this work, we present a description of the style and the structural architecture of this graben system based on the interpretation of transverse seismic sections and both seismic and field map data. To the junction of the stepover with the north PSZ in the vertical plane, the structure corresponds to an asymmetrical unique graben with a maximal subsidence in its eastern boundary. In this side, it is bounded by a major listric fault with a sub-vertical dip at the surface and lowered in dip angle to approximately 50° at its base. On the other hand, its Western edge is characterized by a beam of antithetic normal faults of lower dip, inclined towards the major fault. At its northern margin, the structural system contains two grabens separated by a horst. The first, which is the main graben, is an extension of the graben described at the junction stepover with north PSZ, and shows the same geometry. The second, developed in the east, is rather symmetrical and bounded by

  14. Part I: Neoacadian to Alleghanian foreland basin development and provenance in the central appalachian orogen, pine mountain thrust sheet Part II: Structural configuration of a modified Mesozoic to Cenozoic forearc basin system, south-central Alaska

    NASA Astrophysics Data System (ADS)

    Robertson, Peter Benjamin

    Foreland and forearc basins are large sediment repositories that form in response to tectonic loading and lithospheric flexure during orogenesis along convergent plate boundaries. In addition to their numerous valuable natural resources, these systems preserve important geologic information regarding the timing and intensity of deformation, uplift and erosion history, and subsidence history along collisional margins, and, in ancient systems, may provide more macroscopic information regarding climate, plate motion, and eustatic sea level fluctuations. This thesis presents two studies focused in the Paleozoic Appalachian foreland basin system along the eastern United States and in the Mesozoic to Cenozoic Matanuska forearc basin system in south-central Alaska. Strata of the Appalachian foreland basin system preserve the dynamic history of orogenesis and sediment dispersal along the east Laurentian margin, recording multiple episodes of deformation and basin development during Paleozoic time. A well-exposed, >600 m thick measured stratigraphic section of the Pine Mountain thrust sheet at Pound Gap, Kentucky affords one of the most complete exposures of Upper Devonian through Middle Pennsylvanian strata in the basin. These strata provide a window into which the foreland basin's development during two major collisional events known as the Acadian-Neoacadian and the Alleghanian orogenies can be observed. Lithofacies analysis of four major sedimentary successions observed in hanging wall strata record the upward transition from (1) a submarine deltaic fan complex developed on a distal to proximal prodelta in Late Devonian to Middle Mississippian time, to (2) a Middle to Late Mississippian carbonate bank system developed on a slowly subsiding, distal foreland ramp, which was drowned by (3) Late Mississippian renewed clastic influx to a tidally influenced, coastal deltaic complex to fluvial delta plain system unconformably overlain by (4) a fluvial braided river complex

  15. Recently active reverse faulting in the Atacama Basin area, northern Chile: Implications for the distribution of convergence across the western South America plate boundary

    NASA Astrophysics Data System (ADS)

    Shyu, J. H.; Gonzalez, G.; Simons, M.; Aron, F.; Veloso, A.

    2007-12-01

    The western South American margin is one of the most active continental plate boundaries in the world. The ongoing convergence between the Nazca plate, or formerly the Farallon plate, and the South American plate produced the wide deformation belt of the Andes. In order to obtain more information about the active deformations in the central Andean belt to better understand the current distribution of convergence across the orogen, we attempted to map major structures that appear to be active recently by their topographic expressions using SRTM DEM and Landsat satellite images, followed by field observations. Results of our mapping show that there are many reverse faults that may be recently active in the area surrounding the Atacama Basin, in the Preandean Depression in northern Chile. These include a series of active reverse faults and related folds at the southeastern corner of the Atacama Basin, a major fold system that may be produced by an underlying fault just east of the basin, and a series of folds that forms the Cordillera de la Sal in the northern and western part of the basin. At the southeastern corner of the Atacama Basin, several geomorphic features indicate that at least some of the structures there have been active quite recently, including small drainages that cut through the folds and form active alluvial fans. Similar features of active river incision across folds are also present in the northern part of the basin. The fold system east of the basin may be one of the most important structures in the area. Deformed lava flows and deflected drainages indicate that this structure has been active recently, and growth strata near the fold suggest that it has been active for several myr. If so, the structure may be a major reverse fault system that defines the eastern boundary of the Atacama Basin, and may thus be an important onland structure that is responsible for absorbing part of the plate convergence.

  16. Prospective air pollutant emissions inventory for the development and production of unconventional natural gas in the Karoo basin, South Africa

    NASA Astrophysics Data System (ADS)

    Altieri, Katye E.; Stone, Adrian

    2016-03-01

    The increased use of horizontal drilling and hydraulic fracturing techniques to produce gas from unconventional deposits has led to concerns about the impacts to local and regional air quality. South Africa has the 8th largest technically recoverable shale gas reserve in the world and is in the early stages of exploration of this resource. This paper presents a prospective air pollutant emissions inventory for the development and production of unconventional natural gas in South Africa's Karoo basin. A bottom-up Monte Carlo assessment of nitrogen oxides (NOx = NO + NO2), particulate matter less than 2.5 μm in diameter (PM2.5), and non-methane volatile organic compound (NMVOC) emissions was conducted for major categories of well development and production activities. NOx emissions are estimated to be 68 tons per day (±42; standard deviation), total NMVOC emissions are 39 tons per day (±28), and PM2.5 emissions are 3.0 tons per day (±1.9). NOx and NMVOC emissions from shale gas development and production would dominate all other regional emission sources, and could be significant contributors to regional ozone and local air quality, especially considering the current lack of industrial activity in the region. Emissions of PM2.5 will contribute to local air quality, and are of a similar magnitude as typical vehicle and industrial emissions from a large South African city. This emissions inventory provides the information necessary for regulatory authorities to evaluate emissions reduction opportunities using existing technologies and to implement appropriate monitoring of shale gas-related activities.

  17. Genetic analysis of South American eastern equine encephalomyelitis viruses isolated from mosquitoes collected in the Amazon Basin region of Peru.

    PubMed

    Kondig, John P; Turell, Michael J; Lee, John S; O'Guinn, Monica L; Wasieloski, Leonard P

    2007-03-01

    Identifying viral isolates from field-collected mosquitoes can be difficult and time-consuming, particularly in regions of the world where numerous closely related viruses are co-circulating (e.g., the Amazon Basin region of Peru). The use of molecular techniques may provide rapid and efficient methods for identifying these viruses in the laboratory. Therefore, we determined the complete nucleotide sequence of two South American eastern equine encephalomyelitis viruses (EEEVs): one member from the Peru-Brazil (Lineage II) clade and one member from the Argentina-Panama (Lineage III) clade. In addition, we determined the nucleotide sequence for the nonstructural P3 protein (nsP3) and envelope 2 (E2) protein genes of 36 additional isolates of EEEV from mosquitoes captured in Peru between 1996 and 2001. The 38 isolates were evenly distributed between lineages II and III virus groupings. However, analysis of the nsP3 gene for lineage III strongly suggested that the 19 isolates from this lineage could be divided into two sub-clades, designated as lineages III and IIIA. Compared with North American EEEV (lineage I, GA97 strain), we found that the length of the nsP3 gene was shorter in the strains isolated from South America. A total of 60 nucleotides was deleted in lineage II, 69 in lineage III, and 72 in lineage IIIA. On the basis of the sequences we determined for South American EEEVs and those for other viruses detected in the same area, we developed a series of primers for characterizing these viruses.

  18. Biochemical characterization of hemoglobins from Caspian Sea sturgeons (Acipenser persicus and Acipenser stellatus).

    PubMed

    Ariaeenejad, Shohreh; Habibi-Rezaei, Mehran; Jamili, Shahla; Fatemi, Mohammad Reza; Poursasan, Najmeh; Ahmad, Faizan; Sheibani, Nader; Kavousi, Kaveh; Moosavi-Movahedi, Ali A

    2012-01-01

    Hemoglobin (Hb) variability is a commonly used index of phylogenetic differentiation and molecular adaptation in fish enabling them to adapt to different ecological conditions. In this study, the characteristics of Hbs from two Sturgeon species of the Southern Caspian Sea Basin were investigated. After extraction and separation of hemoglobin from whole blood, the polyacrylamide gel electrophoresis (SDS-PAGE), cellulose acetate electrophoresis, and isoelectric focusing (IEF) were used to confirm Hb variabilities in these fishes. We showed that although both species have variable Hbs with different isoelectric points, their dominant Hbs can be identified. Ion exchange on CM-cellulose chromatography was used for purification of the dominant Hbs from these fishes. The accuracy of the methods was confirmed by IEF and SDS-PAGE. Spectral studies using fluorescence spectrophotometery indicated that although the Hbs from these fishes had similar properties they exhibited clear differences with human Hb. A comparative study of Hbs alpha-helix secondary substructures was performed by circular dichroism spectropolarimetry (CD) analysis. UV-vis spectrophotometery was also utilized to measure oxygen affinity of Hbs by sodium dithionite. Oxygen affinities of these Hbs were compared using Hb-oxygen dissociation curves. Together, these results demonstrate a significant relationship between oxygen affinity of fish hemoglobins and environmental partial pressure of oxygen.

  19. Modeling relationships between catchment attributes and river water quality in southern catchments of the Caspian Sea.

    PubMed

    Hasani Sangani, Mohammad; Jabbarian Amiri, Bahman; Alizadeh Shabani, Afshin; Sakieh, Yousef; Ashrafi, Sohrab

    2015-04-01

    Increasing land utilization through diverse forms of human activities, such as agriculture, forestry, urban growth, and industrial development, has led to negative impacts on the water quality of rivers. To find out how catchment attributes, such as land use, hydrologic soil groups, and lithology, can affect water quality variables (Ca(2+), Mg(2+), Na(+), Cl(-), HCO 3 (-) , pH, TDS, EC, SAR), a spatio-statistical approach was applied to 23 catchments in southern basins of the Caspian Sea. All input data layers (digital maps of land use, soil, and lithology) were prepared using geographic information system (GIS) and spatial analysis. Relationships between water quality variables and catchment attributes were then examined by Spearman rank correlation tests and multiple linear regression. Stepwise approach-based multiple linear regressions were developed to examine the relationship between catchment attributes and water quality variables. The areas (%) of marl, tuff, or diorite, as well as those of good-quality rangeland and bare land had negative effects on all water quality variables, while those of basalt, forest land cover were found to contribute to improved river water quality. Moreover, lithological variables showed the greatest most potential for predicting the mean concentration values of water quality variables, and noting that measure of EC and TDS have inversely associated with area (%) of urban land use. PMID:25395322

  20. Modeling relationships between catchment attributes and river water quality in southern catchments of the Caspian Sea.

    PubMed

    Hasani Sangani, Mohammad; Jabbarian Amiri, Bahman; Alizadeh Shabani, Afshin; Sakieh, Yousef; Ashrafi, Sohrab

    2015-04-01

    Increasing land utilization through diverse forms of human activities, such as agriculture, forestry, urban growth, and industrial development, has led to negative impacts on the water quality of rivers. To find out how catchment attributes, such as land use, hydrologic soil groups, and lithology, can affect water quality variables (Ca(2+), Mg(2+), Na(+), Cl(-), HCO 3 (-) , pH, TDS, EC, SAR), a spatio-statistical approach was applied to 23 catchments in southern basins of the Caspian Sea. All input data layers (digital maps of land use, soil, and lithology) were prepared using geographic information system (GIS) and spatial analysis. Relationships between water quality variables and catchment attributes were then examined by Spearman rank correlation tests and multiple linear regression. Stepwise approach-based multiple linear regressions were developed to examine the relationship between catchment attributes and water quality variables. The areas (%) of marl, tuff, or diorite, as well as those of good-quality rangeland and bare land had negative effects on all water quality variables, while those of basalt, forest land cover were found to contribute to improved river water quality. Moreover, lithological variables showed the greatest most potential for predicting the mean concentration values of water quality variables, and noting that measure of EC and TDS have inversely associated with area (%) of urban land use.

  1. Assessment of the environmental conditions of the Sarno river basin (south Italy): a stream sediment approach.

    PubMed

    Albanese, Stefano; Iavazzo, Pietro; Adamo, Paola; Lima, Annamaria; De Vivo, Benedetto

    2013-06-01

    The Sarno river basin covers an area of 500 km(2) collecting the waters of Solofrana and Cavaiola tributaries. Originally it manly represents a source of livelihood for inhabitants by fishing and transporting goods; currently, the Sarno river, still partially used for irrigation, is affected by an extreme environmental degradation as a result of uncontrolled outflow of industrial waste. Within the framework of a wider geochemical prospecting project aiming at characterizing the whole territory of the Campania region, 89 stream sediment samples with a sampling density of 1 sample per 5 km(2) were collected in the river basin and analyzed by means of inductively coupled plasma-mass spectrometry in order to assess the environmental conditions at a regional scale. A GIS-aided technique, based on both the actual distribution of potentially harmful elements and their regional background values, was used to generate the maps of the contamination factors and of the contamination degrees for As, Cd, Cr, Cu, Hg, Pb and Zn. Furthermore, a factor analysis was performed to assess the nature and the extent of contamination sources for the river sediments. Results showed that the Sarno river basin could be divided in two "environmental status" units: one, low contaminated, corresponding to the hilly and mountain areas, and the second, from moderately to very highly contaminated, corresponding to the economically developed areas of the valley floor characterized by a high population density. This work was developed within a project that aims to investigate the relationships between environmental pollution and human health by analyzing environmental media (stream sediments, water, soil and vegetation) together with human hair of resident population. In this context, the spatial correlation between the extremely compromised environmental conditions of developed areas and the incidence rate of liver cancer in the same area was also explored posing the need of a careful costs

  2. Identification, mapping, and analysis of possible evidences of active petroleum systems in the Colorado Basin, offshore Argentina, South America

    NASA Astrophysics Data System (ADS)

    Loegering, Markus; Anka, Zahie; Rodriguez, Jorge; Marchal, Denis; di Primio, Rolando; Vallejo, Eduardo; Kohler, Guillermina; Pangaro, Francisco

    2010-05-01

    The analysis of a dense 2D seismic reflection dataset and 12 exploration wells data, allowed us to reconstruct the geological evolution of the Colorado Basin, offshore Argentina. We identified and mapped the major syn- and post-rift seismic sequences, and their boundaries such as unconformities and regional seismic markers, present on the continental shelf and slope (water depths from 50 to 1800 m) of the Colorado Basin. Seismic-to-well log correlations, as well as integration with biostratigraphic data provided a chrono-stratigraphic framework for the interpreted horizons. The construction of isochronal (twt) maps provided a 3D spatial visualisation of the stratigraphic relationship among the sequences. The maps show a change in configuration from the break-up unconformity (130 Ma) to the present-day seafloor. The break-up unconformity displays a central EW-elongated graben which prevails on the overlying sequences up to the Miocene. The EW Colorado basin turns NW-SE towards the East, going perpendicular to the present-day continental margin (oriented NE-SW). The strong obliquity of the basin orientation related to the direction corresponding to the opening of the South Atlantic (NE-SW) suggests a structural control from the pre-rift basement on the rift and post-rift sequences. Starting from the break-up unconformity, the history of basin filling is illustrated up to the flat seafloor. The basin sag phase is represented by the sequences deposited between the break-up unconformity and the Colorado discontinuity (Aptian to Campanian). The Campanian to Eocene successions are more or less parallel- layered suggesting sequence aggradation. The distribution of liquid/gas hydrocarbon-leakage features (i.e. gas chimneys, mud volcanoes, and seabed pockmarks) should allow the definition of potential migration pathways. In this sense, a systematic mapping of these paleo- and present-day features observed in the seismic profiles has been performed and their distribution was

  3. Development of Paleogene depressions and deposition of Lacustrine source rocks in the Pearl River Mouth basin, northern margin of the South China Sea

    SciTech Connect

    Wang, Chunxiu; Sun, Yuxiao

    1994-11-01

    A more accurate, integrated chronostratigraphic framework is applied to the analysis of the development of Paleogene depressions in the Pearl River Mouth basin. The results of our study show that the development of these depressions was characterized by at least three rifting or basin-forming phases occurring during these periods: late Paleocene (Late Cretaceous?)-middle Eocene, late Eocene-early Oligocene, and middle-Oligocene-late Oligocene. The transition from rifting stage to postrifting stage in the basin is about 10 m.y. later than the initial spreading of the South China Sea. The prologue of the spreading of the South China Sea began as early as the end of the middle Eocene. Lacustrine source rocks deposited during the basin`s first rifting phase are thick and of good quality; source rocks deposited during the last two phases, which had a sharp increase in sedimentation rate, are of lesser quality, with the exception being those areas where deposits were out of reach of sediment from the northern mainland.

  4. Estimating the GIS-based soil loss and sediment delivery ratio to the sea for four major basins in South Korea.

    PubMed

    Lee, S E; Kang, S H

    2013-01-01

    This paper describes a sediment delivery ratio (SDR) using the Geographic Information System (GIS)-based Revised Universal Soil Loss Equation (RUSLE), to calculate the soil loss and sediment rating curve (SRC) basis of measured data in the six basins of Four Rivers, South Korea. The data set for calculating SDR was prepared during 3 years from 2008 to 2010. Mean soil loss in the six basins of Four Rivers was 515-869 t km(-2) yr(-1) and mean specific sediment yield (SSY) was 20-208 t km(-2) yr(-1) with basin size. The SDR ranged from 0.03 to 0.33 in the six rivers. Most sediment flows in the monsoon period from June to September (mean Max.: >97%; mean Min.: >84%), but SDR is lower than those of similar continental river basins. This is due to environmental factors, for example rainfall characteristics and associated run-off, soil characteristics and cultivated patterns with increasing basin size. This research provides the first application of SDR based on the observed field data in South Korea.

  5. A brief lithostratigraphic review of the Abrahamskraal and Koonap formations of the Beaufort Group, South Africa: Towards a basin-wide stratigraphic scheme for the Middle Permian Karoo

    NASA Astrophysics Data System (ADS)

    Day, Michael Oliver; Rubidge, Bruce Sidney

    2014-12-01

    The basal strata of the Beaufort Group of the South African Karoo Basin, comprising the western Abrahamskraal and eastern Koonap formations, contain the most time extensive record of Middle Permian fossil tetrapods and hold the key to understanding Middle Permian biodiversity change in the continental realm. To determine faunal stratigraphic ranges a reliable lithostratigraphic framework for Middle Permian Beaufort deposits is essential. Until now this has proved difficult to achieve, largely due to the homogeneity of the fluvial succession coupled with structural complexity as a result of Cape Fold Belt orogenesis. Accordingly, the Abrahamskraal Formation has been only locally subdivided on the basis of sandstone packages but regional stratigraphic subdivision has not yet achieved satisfactorily. Collation of stratigraphic sections from around the Karoo Basin for this study demonstrates the presence of four sandstone packages are present within the Abrahamskraal Formation in the south-western corner of the basin. These sandstone packages are given member status, based upon the nomenclature of Le Roux (1985) with the addition of the newly recognised Grootfontein Member. The Combrinkskraal and Grootfontein Members occur in the lower half of the Abrahamskraal Formation and are laterally persistent along the southern margin of the basin. The Koornplaats Member is more restricted to the south west corner of the basin, where it quite thick, suggesting the narrowing of the highly channelized area. The overlying Moordenaars Member, more extensive towards the north than underlying packages, indicates subsequent northwesterly expansion of the locus of active channelization with time. Although thin sandstone packages in the more easterly positioned and stratigraphically equivalent Koonap Formation, this does not facilitate lithostratigraphic subdivision of this part of the stratigraphic succession and may indicate a different form of fluvial architecture. Our study provides

  6. Sediment flux history of Pearl River mouth basin, North margin of South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, S.

    2004-12-01

    This work estimates the solid sediment flux in Pearl River mouth basin from Cenozoic (42Ma). The estimates were derived from isopach maps, seismic reflection profiles and drill holes. Average solid sediment fluxes were calculated for six epochs approximately corresponding to geological periods: Eocene-Lower Oligocene (42-29.3), Upper Oligocene (29.3-23.8), Lower Miocene (23.8-16.4), Middle Miocene (16.4-11.2), Upper Miocene (11.2-5.32), and Pliocene-Pleistocene (5.32-0). The total sediment flux from 42 Ma is 392071.3 km3 and 0.89 km of erosion formed from the onshore drainage basin area. The average erosion rate is 22 m/ Ma. The sediment flux curve shows 3 episodes massive increase in sediment supply, i.e. Upper Oligocene, Middle Miocene and Pliocene-Pleistocene. The first increase related to the break up activity and is the product of elevated rift shoulder. The other two increase peak link to the changing of climate.

  7. Tectonics and types of riftogenic basins of the Scotia Sea, South Atlantic

    NASA Astrophysics Data System (ADS)

    Dubinin, E. P.; Kokhan, A. V.; Teterin, D. E.; Grokhol'sky, A. L.; Kurbatova, E. S.; Sushchevskaya, N. M.

    2016-01-01

    Western, central, and eastern provinces are recognized in the Scotia Sea. They are distinguished by their bottom topography, geophysical characteristics, and crustal structure, which record their different origin and evolution. The western province is characterized by the oceanic crust that formed on the West Scotia Ridge, where active spreading may have ceased as a result of a collision between propagating rift and the structural barrier of the thick continental lithosphere of the Falkland Plateau. The central province is a series of blocks mainly composed of continental crust that subsided to various depths depending on the degree of extension in the course of rifting. These blocks are separated by local areas with oceanic crust formed due to the breakup of the continental crust and diffusive spreading. These areas are characterized by deep bottom and high values of Bouguer anomalies. The southern framework of the central province consists of subsided continental blocks and microcontinents divided by small spreading-type basins formed by lithospheric extension complicated by strike-slip faulting. The eastern province is composed of oceanic crust formed on the backarc spreading East Scotia Ridge. The results of density analysis, analog, and numerical simulations allowed us to explain some features of the structure and evolution of these provinces. The insight into tectonic structure of the provinces and their evolution allowed us to recognize several types of riftogenic basins differing in geodynamics, age, and geological and geophysical characteristics.

  8. Water quality characteristics of Densu River basin in south-east Ghana.

    PubMed

    Amoako, J; Karikari, A Y; Ansa-Asare, O D; Adu-Ofori, E

    2010-01-01

    Water quality of the Densu River was studied by determining the levels of various physico-chemical parameters including trace metals for planning of the basin. The pH range (7.40-8.22) fell within the natural background level 6.5-8.5. The river was moderately hard with high turbidity due to poor farming practices, which result in large quantities of topsoil ending up in the river after rains. The river waters were well oxygenated with a mean DO concentration of 6.3 mg/l. Nitrogen and phosphorus levels were below their natural background values. The Densu River showed an overall ionic dominance pattern of Na > Ca > K > Mg and Cl > HCO(3) > SO(4), a pattern which is an intermediate between fresh and sea water systems. The mean concentrations of metals for the basin followed the order: Fe > Mn > Zn > Pb > Cu > Cd. 84.6% of the sampling sites exceeded the background values of 0.3 mg/l and 0.1 mg/l for Fe and Mn respectively. Other metals Zn, Pb, Cu and Cd were all below their background levels indicating the river is unpolluted with respect to these metals. Water Quality index performed on the data depicted that River Densu is of poor to fairly good water quality. Regular water quality monitoring is recommended.

  9. Geophysical Investigations of Crustal Structure of Cenozoic Rifting Basin in Passive Continental Margin: The Pearl River Mouth Basin, South China Sea

    NASA Astrophysics Data System (ADS)

    Qiu, N.

    2015-12-01

    The Pearl River Mouth Basin (PRMB) initiated in the Cenozoic with rifting, and became a part of the South China Sea (SCS) rifted passive continental margin. Decades of industrial exploration in this proliferous region have produced lots of geological and geophysical data. In order to get the first order crustal scale structure, we integrate well data, multi channel seismic reflection, and the observed gravity field for a joint inversion. The Cenozoic sediment of PRMB comprises of several stratigraphic sequences, including the terrestrial facies, the marine facies and the transitional facies. The sedimentary model takes into account of two main parts that refer to the Paleogene to Neogene unit and the Neogene to Quaternary unit, which were respectively formed during the intercontinental rifting stage and the passive continental margin post-rifting stage. By integrating long cable seismic profiles, interval velocity and performing gravity modelling, we have modelled the sub-sedimentary basement. There are some high-density bodies in the lower part of crust (ρ> 2.8 g/cm3), most of which were probably made up by emplacement from the upper mantle into the lower crust. The crystalline continental crust spans from unstretched domains (as thick as about 25 km) near the continental shelf to extremely thinned domains (of less than 6 km thickness) in the sag center. The presented crust-scale structural model shows that the crystalline crust of the Liwan Sag (LWS) and Baiyun sag (BYS) are thinner than other parts of PRMB, especially, the crystalline crust thickness in BYS is even less than 6 km. we could preliminary infer that the crystalline crust may be more easily stretched and be thinned by the existence of hot and soft substances at the lower crust.

  10. Chapter A. Effects of urbanization on stream ecosystems in the South Platte River basin, Colorado and Wyoming

    USGS Publications Warehouse

    Sprague, Lori A.; Zuellig, Robert E.; Dupree, Jean A.

    2006-01-01

    This report describes the effects of urbanization on physical, chemical, and biological characteristics of stream ecosystems in 28 basins along an urban land-use gradient in the South Platte River Basin, Colorado and Wyoming, from 2002 through 2003. Study basins were chosen to minimize natural variability among basins due to factors such as geology, elevation, and climate and to maximize coverage of different stages of urban development among basins. Because land use or population density alone often are not a complete measure of urbanization, land use, land cover, infrastructure, and socioeconomic variables were integrated in a multimetric urban intensity index to represent the degree of urban development in each study basin. Physical characteristics studied included stream hydrology, stream temperature, and habitat; chemical characteristics studied included nutrients, pesticides, suspended sediment, sulfate, chloride, and fecal bacteria concentrations; and biological characteristics studied included algae, fish, and invertebrate communities. Semipermeable membrane devices (SPMDs), passive samplers that concentrate trace levels of hydrophobic organic contaminants like polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), also were used. The objectives of the study were to (1) examine physical, chemical, and biological responses along the gradient of urbanization; (2) determine the major physical, chemical, and landscape variables affecting the structure of aquatic communities; and (3) evaluate the relevance of the results to the management of water resources in the South Platte River Basin. Commonly observed effects of urbanization on instream physical, chemical, and biological characteristics, such as increased flashiness, higher magnitude and more frequent peak flows, increased concentrations of chemicals, and changes in aquatic community structure, generally were not observed in this study. None of the hydrologic, temperature, habitat

  11. Hydrocarbon- and ore-bearing basinal fluids: a possible link between gold mineralization and hydrocarbon accumulation in the Youjiang basin, South China

    NASA Astrophysics Data System (ADS)

    Gu, X. X.; Zhang, Y. M.; Li, B. H.; Dong, S. Y.; Xue, C. J.; Fu, S. H.

    2012-08-01

    The Youjiang basin, which flanks the southwest edge of the Yangtze craton in South China, contains many Carlin-type gold deposits and abundant paleo-oil reservoirs. The gold deposits and paleo-oil reservoirs are restricted to the same tectonic units, commonly at the basinal margins and within the intrabasinal isolated platforms and/or bioherms. The gold deposits are hosted by Permian to Triassic carbonate and siliciclastic rocks that typically contain high contents of organic carbon. Paragenetic relationships indicate that most of the deposits exhibit an early stage of barren quartz ± pyrite (stage I), a main stage of auriferous quartz + arsenian pyrite + arsenopyrite + marcasite (stage II), and a late stage of quartz + calcite + realgar ± orpiment ± native arsenic ± stibnite ± cinnabar ± dolomite (stage III). Bitumen in the gold deposits is commonly present as a migrated hydrocarbon product in mineralized host rocks, particularly close to high grade ores, but is absent in barren sedimentary rocks. Bitumen dispersed in the mineralized rocks is closely associated and/or intergrown with the main stage jasperoidal quartz, arsenian pyrite, and arsenopyrite. Bitumen occurring in hydrothermal veins and veinlets is paragenetically associated with stages II and III mineral assemblages. These observations suggest an intimate relationship between bitumen precipitation and gold mineralization. In the paleo-petroleum reservoirs that typically occur in Permian reef limestones, bitumen is most commonly observed in open spaces, either alone or associated with calcite. Where bitumen occurs with calcite, it is typically concentrated along pore/vein centers as well as along the wall of pores and fractures, indicating approximately coeval precipitation. In the gold deposits, aqueous fluid inclusions are dominant in the early stage barren quartz veins (stage I), with a homogenization temperature range typically of 230°C to 270°C and a salinity range of 2.6 to 7.2 wt% NaCl eq

  12. Water-quality conditions and streamflow gain and loss of the South Prong of Spavinaw Creek basin, Benton County, Arkansas

    USGS Publications Warehouse

    Joseph, Robert L.; Green, W. Reed

    1994-01-01

    A study of the South Prong of Spavinaw Creek Basin conducted baween July 14 and July 23. 1993. described the surface- and ground-water quality of the basin and the streamflow gain and loss. Water samples were collected from 10 sites on the mainstem of the South Prong of Spavinaw Creek and from 4 sites on tributaries during periods of low to moderate streamflow (less than 11 cubic feet per second). Water samples were collected from 4 wells and 10 springs located in the basin. In 14 surface-water samples, nitrite plus nitrate concentrations ranged from 0.75 to 4.2 milligrams per liter as nitrogen (mg/L). Orthophosphorus concentrations ranged from 0 03 to O. 15 mg/L as phosphorus. Fecal coliform bacteria counts ranged from 61 to 1,400 colonies per 100 milliliters (col/lOO mL), with a median of 120 col/100 mL. Fecal streptococci bacteria counts ranged from 70 to greater than 2,000 col/100 mL with a median of 185 col/lOO mL. Analysis for selected metals collected at one surface-water sites indicates that concentrations were usually below the reporting limit. Diel dissolved oxygen concentrations and temperatures were measured at an upstream and downstream site on the mainstem of the stream. At the upstream site, dissolved oxygen concentrations ranged from 7.2 to 83 mg/L and temperatures ranged from 15.5 to 17.0 C. Dissolved oxygen concentrations were higher and temperature values were lower at lhe upstream site, which is located close to two springs that produce all of the flow at that site. Dissolved nitrite plus nitrate was present in all four wells sampled in the basin with concentrations ranging from 0.04 to 3.5 mg/L as nitrogen. Orthophosphorus was present in concentrations ranging from less than 0.01 to 0.07 mg/L as phosphorus. Volatile organic compound analyses in two wells indicate that toluene was present in both wells and chloroform was present in one well. All other volatile organic compounds were found to be below the reporting limits. Analysis for common

  13. Winged Fruits of Deviacer in the Oligocene from the Ningming Basin in Guangxi, South China

    PubMed Central

    Chen, Yunfa; Manchester, Steven R.

    2015-01-01

    Deviacer guangxiensis Chen & Manchester sp. nov. is described based on asymmetric samaras from the Oligocene Ningming Formation in Guangxi, South China, representing the first documentation of Deviacer fossils in Asia. The Oligocene species, with relatively large fruits, represents the youngest record of the genus so far known; all other records are from the Paleocene and Eocene, or late Eocene—early Oligocene in western North America and Europe. It indicates that the extinct genus, Deviacer, was widely distributed in the northern hemisphere during the Paleogene. PMID:26624897

  14. Winged Fruits of Deviacer in the Oligocene from the Ningming Basin in Guangxi, South China.

    PubMed

    Chen, Yunfa; Manchester, Steven R

    2015-01-01

    Deviacer guangxiensis Chen & Manchester sp. nov. is described based on asymmetric samaras from the Oligocene Ningming Formation in Guangxi, South China, representing the first documentation of Deviacer fossils in Asia. The Oligocene species, with relatively large fruits, represents the youngest record of the genus so far known; all other records are from the Paleocene and Eocene, or late Eocene-early Oligocene in western North America and Europe. It indicates that the extinct genus, Deviacer, was widely distributed in the northern hemisphere during the Paleogene. PMID:26624897

  15. Geochemical Characterisation as a means of Distinguishing between Deep and Shallow Groundwater in the Karoo Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Swana, K.

    2015-12-01

    Although heralded as the solution to the world's energy shortage, shale-gas is proving to be extremely problematic from an environmental perspective. Fracking has in many instances led to the contamination of shallow groundwater resources in the vicinity of extraction sites. South Africa has significant energy issues and fracking has many attractions for the country as whole from an alternative energy supply perspective and also from a development perspective. However, the target region, the Karoo Basin, is a very water stressed region with significant ecological and agricultural value. The aim of this project was to establish whether it is possible to distinguish between deep and shallow groundwater throughout the Karoo using a wide variety of geochemical tracers. However, it is not possible to access groundwater located at depths of > 2500m. Therefore, waters derived from thermal springs and boreholes were used as proxies for deep groundwater. Eight locations within the Karoo Basin were chosen for sampling. Two sites were sampled at each location, one from a thermal spring or borehole and one from a shallow borehole in close proximity to the deep site. All of the samples were measured for temperature, pH, EC and alkalinity in the field and collected for major cations and anions, trace elements, O and H isotopes, Sr, B, Ra, Rn and CDIC isotopes, carbon 14, tritium, chlorine 36, He 4, and noble gases. From these analyses it was possible to differentiate thermal groundwater from shallow groundwater. The thermal groundwaters are interpreted to be deep because of their low carbon 14 content and further work, such as comparison of residence times using applicable tracers, is being completed to confirm this. A provisional list of tracers most reliable in identifying deep and shallow groundwater in the area has been developed and this can be used for monitoring programmes to assess the interaction of deep and shallow groundwater should fracking commence in the Karoo.

  16. Structural relationship of the Beartooth Mountains and Big Horn basin in south-central Montana and northwestern Wyoming

    SciTech Connect

    Clark, D.M. )

    1991-06-01

    Geologic structure along the Beartooth Mountain front and adjacent Big Horn basin in south-central Montana and northwestern Wyoming has been the subject of considerable debate for many years. Directional drilling by Amoco Production Company, located on the northeast corner of the Beartooth block, indicates three things. (1) Western Big Horn basin Paleozoic and Mesozoic sections recumbently folded 2 mi (3.2 km) under the northeast corner of the Beartooth block, measured horizontally from the surface exposure of the Beartooth fault. (2) The main Beartooth fault dips 19{degrees} northwest at a depth of 8,300 to 8,400 ft (2,530 to 2,560 km), 1 mi (1.6 km) from the surface exposure of the main Beartooth fault. (3) The main Beartooth fault appears to be a component of a complex fault system which horizontally displaces and faults-out formations in both the Paleozoic and Mesozoic section on the upper limb of the recumbent fold. In addition to the drilling data, interior Beartooth Mountain faults, with dominant northeast and east-west structural orientation, show reactivation of left-lateral movement, intersecting the Beartooth front and offsetting Paleozoic and Mesozoic sections 1-2 mi (1.6-3.2 km) horizontally. Reactivation of some of these faults seems to coincide with the intrusion of Tertiary (Eocene ) igneous bodies along some of the same structural trends. Beartooth front fold orientation and fault movement correlated with a reexamination of internal block fault systems lend additional weight to the argument of horizontal compression as a major factor in late Laramide formation of geologic structure along the northeast face of the Beartooth Mountains.

  17. Occurrence of authigenic beidellite in the Eocene transitional sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Robin, Valentin; Hebert, Benoit; Beaufort, Daniel; Sardini, Paul; Tertre, Emmanuel; Regnault, Olivier; Descostes, Michael

    2015-05-01

    This paper describes the petrographic properties and the clay mineralogy of Eocene sandy sediments of the Chu-Saryssu basin (South-Central Kazakhstan), in which dioctahedral smectite formed during shallow burial diagenesis (eogenesis). Evidence from petrography and clay mineralogy supports the successive occurrence of kaolinite and dioctahedral smectite during the eogenetic processes, which may have resulted from a change from wet and humid to semi-arid or arid climatic conditions. An original result of this study is the predominantly beidellitic nature of the authigenic smectite, which was determined via X-ray diffraction (XRD, using the Hofmann-Klemen test) and Fourier transform infrared spectroscopy (FTIR) investigations and chemical microanalysis. The crystal-chemical investigations indicate a rather homogeneous chemical composition of the smectite at the regional scale, and the following unit formula is proposed: (Si4 +3.65Al3 +0.35)(Al3 +1.65Fe3 +0.21Mg2 +0.14)O10(OH)2Na+0.10Mg2 +0.11Ca2 +0.04K+0.07. This type of smectite has been interpreted as representative of mixed layers of montmorillonite and beidellite. The fact that the smectite that formed primarily in the unconsolidated sandy sediments is close to beidellite, rather than montmorillonite, may have a major impact on the rate of further illitization in the Chu-Saryssu basin. Indeed, the crystal chemistry of beidellite is more favorable to illitization, and the presence of this mineral provides new insights concerning the different rates of illitization between sandstones and shale formations observed worldwide.

  18. Remagnetization of lower Silurian black shale and insights into shale gas in the Sichuan Basin, south China

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Jia, Dong; Yin, Hongwei; Liu, Mancang; Xie, Wuren; Wei, Guoqi; Li, Yongxiang

    2016-02-01

    The organic-rich lower Silurian shale of the Longmaxi Formation in the Sichuan Basin is the most important target for shale-gas exploration in China. Most Paleozoic rocks of the Sichuan Basin have experienced extraordinarily pervasive remagnetizations. To test a hypothesized connection between hydrocarbon generation and remagnetization and contribute to shale-gas exploration in the region, we undertook an integrated magnetic, geochemical, and petrographic study of 160 specimens from the shale. The results suggest that the shale contains a reliable remanent magnetization (Dec = 41.4°, Inc = 40.8°, and α95 = 6.8°). The magnetization predates tilting, and the paleopole plots close to the Late Triassic segment of the south China apparent polar wander path. The rock magnetic data and scanning electron microscope (SEM) observations confirm that framboidal magnetites carry the bulk of the magnetization, which suggest a Late Triassic chemical remanent magnetization in the shale. 87Sr/86Sr and magnetic analyses indicate that the amount of magnetite was unaffected by fluid alterations around the veins but is strongly covariant with the amount of total organic matter. Moreover, SEM observations reveal possible evidence of the replacement of pyrite framboids by magnetite, probably in the presence of organic acids. These analyses, therefore, suggest that the remagnetization was caused by organic maturation rather than orogenic fluids and that the maturation occurred in the Late Triassic. This timing of organic maturation has been validated by independent modeling studies and provides important constraints on the complex thermal history of the Longmaxi Shale as well as contributing to shale-gas exploration efforts.

  19. Petrogenesis of Mesoproterozoic lamproite dykes from the Garledinne (Banganapalle) cluster, south-western Cuddapah Basin, southern India

    NASA Astrophysics Data System (ADS)

    Rao, N. V. Chalapathi; Atiullah; Kumar, Alok; Sahoo, Samarendra; Nanda, Purnendu; Chahong, Ngazimpi; Lehmann, B.; Rao, K. V. S.

    2016-04-01

    We report mineral chemistry and whole-rock major and trace-element geochemistry for a recent find of Mesoproterozoic (~1.4 Ga) lamproites from the Garledinne (Banganapalle) cluster, south-western part of the Paleo-Mesoproterozoic Cuddapah Basin, southern India. The Garledinne lamproites occur as WNW-ESE-trending dykes that have undergone varying degree of pervasive silicification and carbonate alteration. Nevertheless, their overall texture and relict mineralogy remain intact and provide important insights into the nature of their magmas. The lamproite dykes have porphyritic to weakly porphyritic textures comprising pseudomorphed olivine macrocrysts and microphenocrysts, titanian phlogopite microphenocrysts, spinel having a compositional range from chromite to rarely magnesiochromite, Sr-rich apatite and niobian rutile. The Garledinne and other Cuddapah Basin lamproites (Chelima and Zangamarajupalle) collectively lack sanidine, clinopyroxene, potassic richterite, and titanite and are thus mineralogically distinct from the nearby Mesoproterozoic lamproites (Krishna and Ramadugu) in the Eastern Dharwar Craton, southern India. The strong correlation between various major and trace elements coupled with high abundances of incompatible and compatible trace elements imply that alteration and crustal contamination have had a limited effect on the whole-rock geochemistry (apart from K2O and CaO) of the Garledinne lamproites and that olivine fractionation played an important role in their evolution. The Garledinne lamproites represent small-degree partial melts derived from a refractory (previously melt extracted) peridotitic mantle source that was subsequently metasomatised (enriched) by carbonate-rich fluids/melts within the garnet stability field. The involvement of multiple reservoirs (sub-continental lithospheric mantle and asthenosphere) has been inferred in their genesis. The emplacement of the Garledinne lamproites is linked to extensional events, across the various

  20. Anastomosing river deposits, sedimentation rates and basin subsidence, Magdalena River, northwestern Colombia, South America

    NASA Astrophysics Data System (ADS)

    Smith, Derald G.

    1986-02-01

    Situated in a tectonically active foreland basin, the Magdalena River consists of vertically accreting, levee-confined channels and adjacent extensive wetlands, which are interpreted as an anastomosing river sedimentary system. Equivalent rates of basin filling and subsidence average 3.8 mm yr -1 based on 18 14C dates from five bore holes drilled to depths of 55 m and sediment transport budgets from 35 years of measurement. Located in a savanna-tropical climate, anastomosing river deposits of the Magdalena are remarkably similar to the anastomosing deposits of the upper Columbia River in a temperate-cold climate in western Canada, suggesting that climate is not a controlling factor of anastomosis. The geometry of anastomosing channel-fills in the Magdalena consists of stratigraphically non-uniform, low sinuous, narrow stringers of sand up to 30 m thick by 600 m wide, a width-depth ratio of 20. Thin (1-2 m) off-channel crevasse-splay sand sheets extend laterally up to 10 km distance. When buried, both sand deposits become encased by lacustrine or marsh mud to form stratigraphic traps. While there are few modern anastomosing river systems as compared to braiding and meandering, there may be a disproportionately large number of ancient anastomosed fluvial rock sequences due to the rapid rate of vertical accretion. Such a different depositional style and geometry of sand bodies have considerable significance in the interpretation of some ancient fluvial rock sequences because it provides an alternative to the meandered and braided-river deposition models.

  1. Chemical weathering inferred from riverine water chemistry in the lower Xijiang basin, South China.

    PubMed

    Sun, Huiguo; Han, Jingtai; Li, Dong; Zhang, Shurong; Lu, Xixi

    2010-09-15

    Seasonal sampling was conducted on 13 sites involving the lower stem of the Xijiang river and its three tributaries to determine the spatial patterns of the riverine water chemistry and to quantify the chemical weathering rates of carbonate and silicate of the bedrock. Results indicate that the major ions in the Xijiang river system are dominated by Ca(2+) and HCO(3)(-) with a higher concentration of total dissolved solids, characteristic of the drainages developed on typical carbonate regions. Obvious spatial variations of major ion concentrations are found at various spatial scales, which are dominantly controlled by the lithology particularly carbonate distribution in the region. The four selected rivers show similar seasonal variations in major ions, with lower concentrations during the rainy season. Runoff is the first important factor for controlling the weathering rate in the basin, although increasing temperature and duration of water-rock interaction could make positive contributions to the enhancement of chemical weathering. The chemical weathering rates range from 52.6 to 73.7 t/km(2)/yr within the lower Xijiang basin and carbonate weathering is over one order of magnitude higher than that of silicates. CO(2) consumption rate by rock weathering is 2.0 x 10(11) mol/yr, of which more than 60% is contributed by carbonate weathering. The flux of CO(2) released to the atmosphere-ocean system by sulfuric acid-induced carbonate weathering is 1.1 x 10(5) mol/km(2)/yr, comparable with the CO(2) flux consumed by silicate weathering.

  2. RECONNAISSANCE ASSESSMENT OF CO2 SEQUESTRATION POTENTIAL IN THE TRIASSIC AGE RIFT BASIN TREND OF SOUTH CAROLINA, GEORGIA, AND NORTHERN FLORIDA

    SciTech Connect

    Blount, G.; Millings, M.

    2011-08-01

    A reconnaissance assessment of the carbon dioxide (CO{sub 2}) sequestration potential within the Triassic age rift trend sediments of South Carolina, Georgia and the northern Florida Rift trend was performed for the Office of Fossil Energy, National Energy Technology Laboratory (NETL). This rift trend also extends into eastern Alabama, and has been termed the South Georgia Rift by previous authors, but is termed the South Carolina, Georgia, northern Florida, and eastern Alabama Rift (SGFAR) trend in this report to better describe the extent of the trend. The objectives of the study were to: (1) integrate all pertinent geologic information (literature reviews, drilling logs, seismic data, etc.) to create an understanding of the structural aspects of the basin trend (basin trend location and configuration, and the thickness of the sedimentary rock fill), (2) estimate the rough CO{sub 2} storage capacity (using conservative inputs), and (3) assess the general viability of the basins as sites of large-scale CO{sub 2} sequestration (determine if additional studies are appropriate). The CO{sub 2} estimates for the trend include South Carolina, Georgia, and northern Florida only. The study determined that the basins within the SGFAR trend have sufficient sedimentary fill to have a large potential storage capacity for CO{sub 2}. The deeper basins appear to have sedimentary fill of over 15,000 feet. Much of this fill is likely to be alluvial and fluvial sedimentary rock with higher porosity and permeability. This report estimates an order of magnitude potential capacity of approximately 137 billion metric tons for supercritical CO{sub 2}. The pore space within the basins represent hundreds of years of potential storage for supercritical CO{sub 2} and CO{sub 2} stored in aqueous form. There are many sources of CO{sub 2} within the region that could use the trend for geologic storage. Thirty one coal fired power plants are located within 100 miles of the deepest portions of

  3. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene

    PubMed Central

    Padmalal, Damodaran; Limaye, Ruta B.; S., Vishnu Mohan; Jennerjahn, Tim; Gamre, Pradeep G.

    2016-01-01

    Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic—rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub—coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon—lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0–3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of

  4. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

    PubMed

    Kumaran, Navnith K P; Padmalal, Damodaran; Limaye, Ruta B; S, Vishnu Mohan; Jennerjahn, Tim; Gamre, Pradeep G

    2016-01-01

    Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land

  5. Discovery of South American suckermouth armored catfishes (Loricariidae, Pterygoplichthys spp.) in the Santa Fe River drainage, Suwannee River basin, USA

    USGS Publications Warehouse

    Nico, Leo G.; Butt, Peter L.; Johnston, Gerald R.; Jelks, Howard L.; Kail, Matthew; Walsh, Stephen J.

    2012-01-01

    We report on the occurrence of South American suckermouth armored catfishes (Loricariidae) in the Suwannee River basin, southeastern USA. Over the past few years (2009-2012), loricariid catfishes have been observed at various sites in the Santa Fe River drainage, a major tributary of the Suwannee in the state of Florida. Similar to other introduced populations of Pterygoplichthys, there is high likelihood of hybridization. To date, we have captured nine specimens (270-585 mm, standard length) in the Santa Fe River drainage. One specimen taken from Poe Spring best agrees with Pterygoplichthys gibbiceps (Kner, 1854) or may be a hybrid with either P. pardalis or P. disjunctivus. The other specimens were taken from several sites in the drainage and include seven that best agree with Pterygoplichthys disjunctivus (Weber, 1991); and one a possible P. disjunctivus x P. pardalis hybrid. We observed additional individuals, either these or similar appearing loricariids, in Hornsby and Poe springs and at various sites upstream and downstream of the long (> 4 km) subterranean portion of the Santa Fe River. These specimens represent the first confirmed records of Pterygoplichthys in the Suwannee River basin. The P. gibbiceps specimen represents the first documented record of an adult or near adult of this species in open waters of North America. Pterygoplichthys disjunctivus or its hybrids (perhaps hybrid swarms) are already abundant and widespread in other parts of peninsular Florida, but the Santa Fe River represents a northern extension of the catfish in the state. Pterygoplichthys are still relatively uncommon in the Santa Fe drainage and successful reproduction not yet documented. However, in May 2012 we captured five adult catfish (two mature or maturing males and three gravid females) from a single riverine swallet pool. One male was stationed at a nest burrow (no eggs present). To survive the occasional harsh Florida winters, these South American catfish apparently use

  6. Tropical Peat and Peatland Development in the Floodplains of the Greater Pamba Basin, South-Western India during the Holocene.

    PubMed

    Kumaran, Navnith K P; Padmalal, Damodaran; Limaye, Ruta B; S, Vishnu Mohan; Jennerjahn, Tim; Gamre, Pradeep G

    2016-01-01

    Holocene sequences in the humid tropical region of Kerala, South-western (SW) India have preserved abundance of organic-rich sediments in the form of peat and its rapid development in a narrow time frame towards Middle Holocene has been found to be significant. The sub-coastal areas and flood plains of the Greater Pamba Basin have provided palaeorecords of peat indicating that the deposits are essentially formed within freshwater. The combination of factors like stabilized sea level and its subsequent fall since the Middle Holocene, topographic relief and climatic conditions led to rapid peat accumulation across the coastal lowlands. The high rainfall and massive floods coupled with a rising sea level must have inundated > 75% of the coastal plain land converting it into a veritable lagoon-lake system that eventually led to abrupt termination of the forest ecosystem and also converted the floodplains into peatland where accumulation of peat almost to 2.0-3.0 m thickness in coastal lowlands and river basins during the shorter interval in the Middle Holocene. Vast areas of the coastal plains of Kerala have been converted into carbon rich peatland during the Middle Holocene and transforming the entire coastal stretch and associated landforms as one of the relatively youngest peatlands in the extreme southern tip of India. Unlike the uninterrupted formation of peatlands of considerable extent during the Holocene in Southeast Asia, the south Peninsular Indian region has restricted and short intervals of peatlands in the floodplains and coastal lowlands. Such a scenario is attributed to the topographic relief of the terrain and the prevailing hydrological regimes and environmental conditions as a consequence of monsoon variability since Middle Holocene in SW India. Considering the tropical coastal lowlands and associated peatlands are excellent repositories of carbon, they are very important for regional carbon cycling and habitat diversity. The alarming rate of land

  7. Influence of orogenesis in basin evolution in the central Asian republics of the CIS

    SciTech Connect

    Otto, S.

    1995-08-01

    A regional synthesis of the structural geology of the central Asia region of the CIS is presented, the study area lying between the Caspian Sea and China and stretching from the Aral Sea south to Afghanistan. Structural analysis of central Asia illustrates the creation of major regional faults that have acted as planes of weakness during the evolution of the region. These faults were repeatedly reactivated in phases of orogenesis, some of which were centred far from the study area. It is shown that the Eurasian Plate did not act as a rigid, unyielding lithospheric unit, but deformed internally as a response to compression at its margins. The influence of these orogenic events on the evolution of basins in the area is described by means of maps and serial sections. The role of major faults in governing the spatial distribution of structural traps in petroleum basins within the study area is also examined. These basins are largely gas-prone, and have ultimate recoverable reserves estimated at over 290 trillion cubic feet of gas and 27 billion barrels of liquids.

  8. New insight on the opening of the South China Sea basin

    NASA Astrophysics Data System (ADS)

    Hsu, Shu-Kun; Armada, Leo; Doo, Wen-Bin; Yeh, Yi-Ching

    2016-04-01

    The tectonic evolution of the South China Sea (SCS) plays an important role on the geodynamics of Southeast Asia. Recent results from the International Ocean Discovery Program (IODP) Expedition 349 confirmed that the SCS seafloor spreading stopped in the middle Miocene. However, the definite mechanism for the SCS opening is still enigmatic. Using multi-beam bathymetric data, seismic reflection profiles and geomagnetic modeling, we have analyzed the seafloor-spreading pattern and geomagnetic stripes of the SCS. Our results show that an excessive magma supply affecting the SCS occurred at the Early Miocene Climatic Optimum (EMCO). Consequently, four major tectonic events ensued. Firstly, the East Subbasin of the SCS dramatically changed its seafloor spreading direction from north-south to northwest-southeast. Secondly, a northeastward propagating rift occurred in the East Subbasin but stopped in the middle Miocene, just before the cessation of the SCS seafloor spreading. Thirdly, the opening of the SCS extended southwestward and created the Southwest Subbasin. Fourthly, the initiation of the southeastward subduction of the SCS lithosphere occurred and the Manila Trench was formed.

  9. Hydrogeologic framework and groundwater/surface-water interactions of the South Fork Nooksack River Basin, northwestern Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.

    2014-01-01

    A hydrogeologic framework of the South Fork (SF) Nooksack River Basin in northwestern Washington was developed and hydrologic data were collected to characterize the groundwater-flow system and its interaction with surface‑water features. In addition to domestic, agricultural, and commercial uses of groundwater within the SF Nooksack River Basin, groundwater has the potential to provide ecological benefits by maintaining late-summer streamflows and buffering stream temperatures. Cold-water refugia, created and maintained in part by groundwater, have been identified by water-resource managers as key elements to restore the health and viability of threatened salmonids in the SF Nooksack River. The SF Nooksack River drains a 183-square mile area of the North Cascades and the Puget Lowland underlain by unconsolidated glacial and alluvial sediments deposited over older sedimentary, metamorphic, and igneous bedrock. The primary aquifer that interacts with the SF Nooksack River was mapped within unconsolidated glacial outwash and alluvial sediment. The lower extent of this unit is bounded by bedrock and fine-grained, poorly sorted unconsolidated glaciomarine and glaciolacustrine sediments. In places, these deposits overlie and confine an aquifer within older glacial sediments. The extent and thickness of the hydrogeologic units were assembled from mapped geologic units and lithostratigraphic logs of field-inventoried wells. Generalized groundwater-flow directions within the surficial aquifer were interpreted from groundwater levels measured in August 2012; and groundwater seepage gains and losses to the SF Nooksack River were calculated from synoptic streamflow measurements made in the SF Nooksack River and its tributaries in September 2012. A subset of the field-inventoried wells was measured at a monthly interval to determine seasonal fluctuations in groundwater levels during water year 2013. Taken together, these data provide the foundation for a future groundwater

  10. Future Water Management in the South Platte River Basin: Impacts of Hydraulic Fracturing, Population, Agriculture, and Climate Change in a Semi-Arid Region.

    NASA Astrophysics Data System (ADS)

    Walker, E. L.; Hogue, T. S.; Anderson, A. M.; Read, L.

    2015-12-01

    In semi-arid basins across the world, the gap between water supply and demand is growing due to climate change, population growth, and shifts in agriculture and unconventional energy development. Water conservation efforts among residential and industrial water users, recycling and reuse techniques and innovative regulatory frameworks for water management strive to mitigate this gap, however, the extent of these strategies are often difficult to quantify and not included in modeling water allocations. Decision support systems (DSS) are purposeful for supporting water managers in making informed decisions when competing demands create the need to optimize water allocation between sectors. One region of particular interest is the semi-arid region of the South Platte River basin in northeastern Colorado, where anthropogenic and climatic effects are expected to increase the gap between water supply and demand in the near future. Specifically, water use in the South Platte is impacted by several high-intensity activities, including unconventional energy development, i.e. hydraulic fracturing, and large withdrawals for agriculture; these demands are in addition to a projected population increase of 100% by 2050. The current work describes the development of a DSS for the South Platte River basin, using the Water Evaluation and Planning system software (WEAP) to explore scenarios of how variation in future water use in the energy, agriculture, and municipal sectors will impact water allocation decisions. Detailed data collected on oil and gas water use in the Niobrara shale play will be utilized to predict future sector use. We also employ downscaled climate projections for the region to quantify the potential range of water availability in the basin under each scenario, and observe whether or not, and to what extent, climate may impact management decisions at the basin level.

  11. Canadian groundwater inventory: Regional hydrogeological characterization of the south-central part of the maritimes basin

    USGS Publications Warehouse

    Rivard, C.; Michaud, Y.; Deblonde, C.; Boisvert, V.; Carrier, C.; Morin, R.H.; Calvert, T.; Vigneault, H.; Conohan, D.; Castonguay, S.; Lefebvre, R.; Rivera, A.; Parent, M.

    2008-01-01

    The Maritimes Groundwater Initiative (MGWI) is a large, integrated, regional hydrogeological study focusing on a representative area of the Maritimes Basin in eastern Canada. The study area covers a land surface of 10 500 km2, of which 9 400 km2 are underlain by sedimentary rocks. This sedimentary bedrock is composed of a sequence of discontinuous strata of highly variable hydraulic properties, and is generally overlain by a thin layer of glacial till(mostly 4-8 m thick, but can reach 20 m). Depending on the area, 46 to 100% of the population relieson groundwater for water supply, either from municipal wells or from private residential wells. The main objectives of this project were to improve the general understanding of groundwater-flow dynamics and to provide baseline information and tools for a regional groundwater-resource assessment. This bulletin presents the current state of understanding of this hydrogeological system, along with the methodology used to characterize and analyze its distinct behaviour at three different scales. This regional bedrock aquifer system contains confined and unconfined zones, and each of its lenticular permeable strata extends only a few kilometres. Preferential groundwater recharge occurs where sandy till is present. The mean annual recharge rate to the bedrock is estimated to range between 130 and 165 mm/a. Several geological formations of this basin provide good aquifers, with hydraulic conductivity in the range 5x10-6 to 10-4m/s. Based on results of numerical flow modelling, faults were interpreted to have a key role in the regional flow. Pumping-test results revealed that the fractured aquifers can locally be very heterogeneous and anisotropic, but behave similarly to porous media. Work performed at the local scale indicated that most water-producing fractures seem to be subhorizontal and generally oriented in a northeasterly direction, in agreement with regional structures and pumping-test results. Almost all residential

  12. Assessment of undiscovered oil resources in the Bakken and Three Forks Formations, Williston Basin Province, Montana, North Dakota, and South Dakota, 2013

    USGS Publications Warehouse

    Gaswirth, Stephanie B.; Marra, Kristen R.; Cook, Troy A.; Charpentier, Ronald R.; Gautier, Donald L.; Higley, Debra K.; Klett, Timothy R.; Lewan, Michael D.; Lillis, Paul G.; Schenk, Christopher J.; Tennyson, Marilyn E.; Whidden, Katherine J.

    2013-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean undiscovered volumes of 7.4 billion barrels of oil, 6.7 trillion cubic feet of associated/dissolved natural gas, and 0.53 billion barrels of natural gas liquids in the Bakken and Three Forks Formations in the Williston Basin Province of Montana, North Dakota, and South Dakota.

  13. Petroleum potential and over-pressuring in the molassic deposits of the south-eastern part of the South Adriatic Basin

    SciTech Connect

    Gjoka, M.; Dulaj, A.

    1995-08-01

    The southeastern portion of the South Adriatic basin extends onshore in Albania and is filled with a sequence of interbedded clays, sandstones and siltstones of Cenozoic age accumulated under turbiditic, slope, shelf, deltaic and, rarely, continental depositional conditions. Geochemical data suggest a fairly uniform vertical and lateral distribution of organic matter, with TOC values ranging from 0.1 to 0.4 wt%. Average organic matter content is 0.28 wt%. Kerogen is predominantly gas-prone, Type IIIa (Huminite-Inertinite) and IIIb (Inertinite-Huminite), and is thermally immature to marginally mature, even at depths of 6000 m. Vitrinite reflectance (Ro) values range from 0.3 to 0.5; the average geothermal gradient of the region is about 16{degrees}C/100 m. Three main gas zones can be recognized in the Pliocene to Middle Miocene (Serravallian) sequence: (1) a biogenic gas zone at depths of 1200-1500 m; (2) a mixed biogenic-thermogenic zone between 1500 and 4500-W m, and, (3) a thermogenic gas zone below 4500-5000 m. Gas is indigenous and has migrated into the sandstone reservoirs from adjacent shales (syngenetic) or deeper sources (syngenetic-long migration). Gas fields discovered to date are associated with crestal culminations and with the eastern flank of structures. The normal hydrostatic gradient for the Neogene sediments is 0.437 Psi/ft, but overpressures have been encountered in numerous wells and are considered a regional phenomenon. The top of the overpressures crosses stratigraphic boundaries. The gradient is gradual and seem to increase in sequences with sandstone content of 15 to 20%. Steep pressure gradients are found on flanks and plunges of structures. Overpressuring is attributed to the very high sedimentation rate (760 m per million year) during the Neogene and resulting undercompacted shales.

  14. Identifying potential gas accumulation sites from Oligocene overpressure data in the Qiongdongnan basin, offshore South China

    SciTech Connect

    Liu Funing )

    1993-05-01

    Overpressure in Oligocene formations in southern Qiongdongnan basin, offshore China, can be determined either by actual measurements in wells or by calculations using data derived from well logs and seismic surveys. The overpressure is mainly the result of undercompaction of Oligocene rocks during rapid loading by Pliocene and Quaternary sedimentation and of the subsequent thermal expansion of fluids in the Oligocene strata. Every formation possesses its own normal compaction trend (plot of shale-interval acoustic transit times vs. depth). The actual fluid pressures and potential pressures can be computed by the equilibrium-depth method. This method must be corrected for the thermal expansion of fluid. The pressure corrections are based on shale-interval transit times from well logs, interval velocities interpreted from vertical seismic profile (VSP) surveys, and stacking velocity from sonic log data of nearby wells. Gas generated from source rocks is assumed to have moved vertically from strata of higher hydraulic pressure potential to those of lower potentials and to have moved laterally and accumulated within areas where the contour closures of a gas equipotential hydraulic-pressure surface (U curves) have lower values. In the study area, the vicinity of the Yacheng gas field, the potential maps (U, gas, and V, water, maps) and hydraulic head profiles can be plotted from values derived either from actual pressure measurements or from calculations. These maps and profiles show prospective areas of gas accumulation. 5 refs., 10 figs., 1 tab.

  15. Early Triassic calcimicrobial mounds and biostromes of the Nanpanjiang basin, south China

    NASA Astrophysics Data System (ADS)

    Lehrmann, Daniel J.

    1999-04-01

    Early Triassic framestones were discovered in the interior of an isolated, marine carbonate platform in the Nanpanjiang basin. The framestones occur in two horizons: (1) the lowermost Triassic (Griesbachian), as biostromes as much as 15 m thick, and (2) the upper part of the Lower Triassic (Smithian or Spathian) as isolated domal or inverted conical mounds as much as 1.5 m thick. The mounds and biostromes consist of a rigid calcimicrobial framework enclosing a network of internal cavities, 1 to 3 cm across, filled with peloidal-skeletal sediment. The framework is made of irregular-to-tufted masses of chambered-to-clotted micrite structures referable to Renalcis, a calcified coccoid cyanobacteria. The framework is reinforced by microbial induced micritic crusts as well as marine cement. Metazoan fossils within the framework include gastropods, bivalves, ostracodes, spirorbids, and brachiopods. The Early Triassic is widely considered to have been a global gap in reef and reef mound development. The global reef gap concept has formed the foundation of models of reef evolution and of the reorganization of reef ecosystems after the end-Permian extinction. These models should be revised to account for the existence of Early Triassic calcimicrobial mounds and biostromes discussed herein.

  16. Human exposure to mercury in San Jorge river basin, Colombia (South America).

    PubMed

    Olivero, Jesus; Johnson, Boris; Arguello, Eduardo

    2002-04-22

    During May-September 1999 human hair samples were collected from the village of Caimito, a fishing community of the state of Sucre (Colombia), in the San Jorge River basin area, and analyzed for total mercury (t-Hg) by cold vapor atomic absorption spectroscopy. T-Hg was measured in both male and female people aged 15-65 years, whose diet mainly consists of fish collected in nearby marshes. Average hair t-Hg concentration in people from Caimito was 4.91 +/- 0.55 microg/g (n = 94), similar to the value previously detected in fishermen living in the gold mining area, 50 km east. Males had similar t-Hg concentrations (4.31 +/- 0.42 microg/g; n = 56) to females (5.78 +/- 1.21 microg/g; n = 38) and there was no difference in t-Hg levels between groups of different age. Mercury content in hair was weakly but significantly associated (R = 0.20, P = 0.05) with fish consumption. PMID:12049405

  17. Mesozoic deformation in the Chaoshan Depression of the Pearl River Mouth Basin, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Jiangyang; Sun, Zhen; Zhang, Yunfan; Li, Fucheng

    2016-05-01

    Newly collected, high resolution multi-beam sonar data are combined with previous bathymetry data to produce an improved bathymetric map of Shatsky Rise oceanic plateau. Bathymetry data show that two massifs within Shatsky Rise are immense central volcanoes with gentle flank slopes declining from a central summit. Tamu Massif is a slightly elongated, dome-like volcanic edifice; Ori Massif is square shaped and smaller in area. Several down-to-basin normal faults are observed on the western flank of the massifs but they do not parallel the magnetic lineations, indicating that these faults are probably not related to spreading ridge faulting. Moreover, the faults are observed only on one side of the massifs, which is contrary to expectations from a mechanism of differential subsidence around the massif center. Multi-beam data show many small secondary cones with different shapes and sizes that are widely-distributed on Shatsky Rise massifs, which imply small late-stage magma sources scattered across the surface of the volcanoes in the form of lava flows or explosive volcanism. Erosional channels occur on the flanks of Shatsky Rise volcanoes due to mass wasting and display evidence of down-slope sediment movement. These channels are likely formed by sediments spalling off the edges of summit sediment cap.

  18. Noblegas Radionuclide (KR-85, AR-39, KR-81) Concentrations in Deep Fracture Waters of the Withwatersrand Basin South Africa

    NASA Astrophysics Data System (ADS)

    Purtschert, R.; Onstott, T. C.; Jiang, W.; Lu, Z.; Müller, P.; van Heerden, E.; Erasmus, M.; Borgonie, G.; Linage, B.; Kuloyo, O.; Kipfer, R.; Brennwald, M. S.

    2013-12-01

    81Kr has been proposed since many years an ideal tracer for dating subsurface fluids on timescales up to 2 million years. However, only recently the method became practicable for real case investigations due to significant analytical improvements [1]. In this study radioactive noble gas isotopes (81Kr, 85Kr and 39Ar) were applied for the characterisation of fracture waters in the deep gold mines of the Witwatersrand Basin, South Africa [2]. Those waters catalyzed interest because of deep microbial communities that persists to depths of over 3 km [3]. The key objective of the present study is to further constrain the origin of the fluids, to determine the timing of deep subsurface life and to test the 81Kr method in all kinds of environments. In contrast to expectations [4] we discovered that underground production of 81Kr is a significant process in the rocks of the Withwatersrand and Ventersdorp Supergroups. All measured 81Kr activities from fracture water were significantly higher than in atmospheric equilibrium. This is most likely related to elevated U/Th concentrations in the rock strata. Radiometric decay dating is complicated in such cases. [1].W. Jiang et al., Geochim. Cosmochim. Acta 91, 1 (2012). [2].T. C. Onstott et al., Geomicrobiology J. 26, 269 (2009). [3].G. Borgonie et al., Nature 474, 79. [4]. B. Lehmann et al, WRR. 29, 2027 (1993).

  19. Seasonal and genotypic changes in escherichia coli phylogenetic groups in the Yeongsan River basin of South Korea.

    PubMed

    Jang, Jeonghwan; Di, Doris Y W; Lee, Anna; Unno, Tatsuya; Sadowsky, Michael J; Hur, Hor-Gil

    2014-01-01

    With 3,480 E. coli strains isolated from the Yeongsan River basin, South Korea, correlations between phylogenetic groups and horizontal fluorophore enhanced rep-PCR (HFERP) genotypes were examined, and environmental factors affecting E. coli phylogenetic groups in the river water were determined. Interestingly, multidimentional scaling (MDS) analyses based on HFERP DNA fingerprint data indicated that E. coli in phylogenetic groups A and B1 were uniquely clustered. Results of self-organized maps (SOMs) analyses also indicated that E. coli phylogenetic groups were seasonally affected by water temperature, with greater occurrences of phylogenetic groups A and B1 in low and high temperature seasons, respectively. The presence of E. coli in phylogenetic groups A and B1 were inversely related. Furthermore, redundancy analysis (RDA) revealed that phylogenetic group B1 correlated positively with temperature, strain diversity, and biochemical oxygen demand (BOD) but negatively with phylogenetic group A. Results of this study indicated that while E. coli strains could be clustered based on their genotypes and environment conditions, their phylogenetic groups did not change in relation to the same conditions. The distributional differences of phylogenetic groups among E. coli populations in different environments may be caused by different genomic adaptability and plasticity of E. coli strains belonging to each phylogenetic group. Although several previous studies have reported different E. coli ecological structures depending on their origins, this study is a first description of the specific environmental factors affecting E. coli phylogenetic groups in river water. PMID:24999864

  20. Construction and preliminary analysis of a deep-sea sediment metagenomic fosmid library from Qiongdongnan Basin, South China Sea.

    PubMed

    Hu, Yongfei; Fu, Chengzhang; Yin, Yeshi; Cheng, Gong; Lei, Fang; Yang, Xi; Li, Jing; Ashforth, Elizabeth Jane; Zhang, Lixin; Zhu, Baoli

    2010-11-01

    Preliminary characterization of the microbial phylogeny and metabolic potential of a deep-sea sediment sample from the Qiongdongnan Basin, South China Sea, was carried out using a metagenomic library approach. An effective and rapid method of DNA isolation, purification, and library construction was used resulting in approximately 200,000 clones with an average insert size of about 36 kb. End sequencing of 600 individual clones from the fosmid library generated 1,051 sequences with an average sequence length of 619 bp. Phylogenetic ascription indicated that this library was dominated by Bacteria, predominantly Proteobacteria, though Planctomycetes were also relatively abundant. Sulfate-reducing and anaerobic ammonium-oxidizing bacteria, which play important roles in the cycling of sedimentary nutrients, were abundant in the library. Cluster of orthologous groups category analysis showed that most of the genes contained in the end sequences were related to metabolism, and with cellular processes and signaling. Functional groups assigned by SEED (subsystems-based annotations) highlighted the existence of 'one-carbon' metabolism within this community as well as identifying functional genes involved in methanogenesis. Furthermore, diverse genes involved in the biodegradation of xenobiotics were found using Kyoto Encyclopedia of Genes and Genomes metabolic pathway analysis. PMID:20514504

  1. Impacts of increased CO2 on the hydrologic response over the Xijiang (West River) basin, South China

    NASA Astrophysics Data System (ADS)

    Niu, Jun; Sivakumar, Bellie; Chen, Ji

    2013-11-01

    Increases in atmospheric carbon dioxide (CO2) concentration levels may affect terrestrial hydrologic processes through changes in evapotranspiration. This study assesses the hydrologic response to the elevated CO2 levels for the Xijiang (West River) basin in South China by applying the Variable Infiltration Capacity (VIC) model. The standard VIC model is modified by incorporating a mechanistic description of vegetation-type specific responses of both stomatal resistance and leaf area increase based on plant physiological studies. The dynamic (monthly) rises of CO2 concentration are introduced to estimate the historical impacts of increased CO2 over the past two decades (1991-2010). The cropland is identified as the most important contributor in the response of streamflow increase for the region. For a doubled atmospheric CO2 concentration scenario (660 ppm), the streamflow might rise about 3% (i.e. 21.8 mm/yr) under the baseline climatic conditions. Decreases in evapotranspiration and associated streamflow increases in response to ambient CO2 exposures are expected to episodically increase the frequency and severity of flood and affect flow-dependent aquatic biota in forested watersheds.

  2. Modeling the oxidative capacity of the atmosphere of the south coast air basin of California. 2. HOx radical production.

    PubMed

    Griffin, Robert J

    2004-02-01

    The production of HOx radicals in the South Coast Air Basin of California is investigated during the smog episode of September 9, 1993 using the California Institute of Technology (CIT) air-quality model. Sources of HOx(hydroxyl, hydroperoxy, and organic peroxy radicals) incorporated into the associated gas-phase chemical mechanism include the combination of excited-state singlet oxygen (formed from ozone (O3) photolysis (hv)) with water, the photolysis of nitrous acid, hydrogen peroxide (H2O2), and carbonyl compounds (formaldehyde (HCHO) or higher aldehydes and ketones), the consumption of aldehydes and alkenes (ALK) by the nitrate radical, and the consumption of alkenes by O3 and the oxygen atom (O). At a given time or location for surface cells and vertical averages, each route of HOx formation may be the greatest contributor to overall formation except HCHO-hv, H2O2-hv, and ALK-O, the latter two of which are insignificant pathways in general. The contribution of the ALK-O3 pathway is dependent on the stoichiometric yield of OH, but this pathway, at least for the studied smog episode, may not be as generally significant as previous research suggests. Future emissions scenarios yield lower total HOx production rates and a shift in the relative importance of individual pathways.

  3. Structural characteristic and origin of intra-continental fold belt in the eastern Sichuan basin, South China Block

    NASA Astrophysics Data System (ADS)

    Li, Chuanxin; He, Dengfa; Sun, Yanpeng; He, Jinyou; Jiang, Zaixing

    2015-11-01

    The fold-and-thrust belt in the eastern Sichuan basin is represented by a series of subparallel chevron anticlines. Under the orogenic tectonic setting within the South China Block in Meso-Cenozoic period and the influence of the multi-layer detachment fault, the deformation of the thrust belt exhibits remarkably layered and large-scale intracontinental thrusting structural characteristics. In this paper, we focus on the structural geometry and deformational mechanisms using the latest two-dimensional (2D) and three-dimensional (3D) seismic reflection data in combination with well and outcrop data. The multi-layer detachment faults, especially the upper gypsum-bearing detachment in the Middle Triassic Jialingjiang Formation and lower detachment with gypsum or shale in the Lower-Middle Cambrian system, directly control the deformational styles of the study area. Interpretation of seismic sections indicates that the fold-and-thrust belt has various deformational styles during folding, including fault-propagation fold, fault-bend fold, and detachment fold with box-fold or pop-up structural geometry. Regional location and structural boundaries play significant roles in controlling the deformational styles, and distinct differences exist among the different anticlines. The Huayingshan anticline located at the front of the thrust belt shows intense structural deformation with northwestward thrusting direction and a relatively weak opposite southeastward thrusting. In addition, the anticlines exhibit structural differences along strike and the fold-and-thrust belt in the northern segment is influenced by the North China Block.

  4. Modeling the oxidative capacity of the atmosphere of the south coast air basin of California. 2. HOx radical production.

    PubMed

    Griffin, Robert J

    2004-02-01

    The production of HOx radicals in the South Coast Air Basin of California is investigated during the smog episode of September 9, 1993 using the California Institute of Technology (CIT) air-quality model. Sources of HOx(hydroxyl, hydroperoxy, and organic peroxy radicals) incorporated into the associated gas-phase chemical mechanism include the combination of excited-state singlet oxygen (formed from ozone (O3) photolysis (hv)) with water, the photolysis of nitrous acid, hydrogen peroxide (H2O2), and carbonyl compounds (formaldehyde (HCHO) or higher aldehydes and ketones), the consumption of aldehydes and alkenes (ALK) by the nitrate radical, and the consumption of alkenes by O3 and the oxygen atom (O). At a given time or location for surface cells and vertical averages, each route of HOx formation may be the greatest contributor to overall formation except HCHO-hv, H2O2-hv, and ALK-O, the latter two of which are insignificant pathways in general. The contribution of the ALK-O3 pathway is dependent on the stoichiometric yield of OH, but this pathway, at least for the studied smog episode, may not be as generally significant as previous research suggests. Future emissions scenarios yield lower total HOx production rates and a shift in the relative importance of individual pathways. PMID:14968860

  5. Seismic features and evolution of a late Miocene submarine channel system in the Yinggehai basin, northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Sun, H.; Jiang, T.; Wang, Z.; Zhang, Y.

    2014-12-01

    Submarine channel is one of key conduits for coarse terrigenous clastic sediments to abyssal plain, which provides the possibility for deepwater hydrocarbon exploration. Recently, a new high-quality 3D seismic data is acquired in south Yinggehai basin (YGHB) and the detailed interpretations on those seismic profiles as well as RMS amplitude attributes and variance slices reveal a submarine channel system developed in late Miocene, which could be supplied from Hainan Island via turbidity currents so that it would be filled with sand-rich turbidites as good hydrocarbon reservoir. Based on the integration between regional seismic survey and some boreholes, the investigations on its infilling architectures and depositional processes are carried out. The results show that it composes two converged submarine channels with two channelized submarine fans to their west and the main submarine channel (MSC) is characterized by a downstream increasing width and is infilled by sediments with high amplitude seismic facies, which could be originated from channelized submarine fans. Furthermore, the complicated depositional processes around the confluence region of these two channels are pointed out and the interactions between the submarine channel system and nearby channelized submarine fans are discussed. The detailed illustration on the seismic features and depositional processes of the subsurface submarine system provides us better understanding deepwater sedimentary dynamics and would be more benefit for the hydrocarbon exploration in similar deepwater area around the world.

  6. Seasonal and Genotypic Changes in Escherichia coli Phylogenetic Groups in the Yeongsan River Basin of South Korea

    PubMed Central

    Jang, Jeonghwan; Di, Doris Y. W.; Lee, Anna; Unno, Tatsuya; Sadowsky, Michael J.; Hur, Hor-Gil

    2014-01-01

    With 3,480 E. coli strains isolated from the Yeongsan River basin, South Korea, correlations between phylogenetic groups and horizontal fluorophore enhanced rep-PCR (HFERP) genotypes were examined, and environmental factors affecting E. coli phylogenetic groups in the river water were determined. Interestingly, multidimentional scaling (MDS) analyses based on HFERP DNA fingerprint data indicated that E. coli in phylogenetic groups A and B1 were uniquely clustered. Results of self-organized maps (SOMs) analyses also indicated that E. coli phylogenetic groups were seasonally affected by water temperature, with greater occurrences of phylogenetic groups A and B1 in low and high temperature seasons, respectively. The presence of E. coli in phylogenetic groups A and B1 were inversely related. Furthermore, redundancy analysis (RDA) revealed that phylogenetic group B1 correlated positively with temperature, strain diversity, and biochemical oxygen demand (BOD) but negatively with phylogenetic group A. Results of this study indicated that while E. coli strains could be clustered based on their genotypes and environment conditions, their phylogenetic groups did not change in relation to the same conditions. The distributional differences of phylogenetic groups among E. coli populations in different environments may be caused by different genomic adaptability and plasticity of E. coli strains belonging to each phylogenetic group. Although several previous studies have reported different E. coli ecological structures depending on their origins, this study is a first description of the specific environmental factors affecting E. coli phylogenetic groups in river water. PMID:24999864

  7. Construction and preliminary analysis of a deep-sea sediment metagenomic fosmid library from Qiongdongnan Basin, South China Sea.

    PubMed

    Hu, Yongfei; Fu, Chengzhang; Yin, Yeshi; Cheng, Gong; Lei, Fang; Yang, Xi; Li, Jing; Ashforth, Elizabeth Jane; Zhang, Lixin; Zhu, Baoli

    2010-11-01

    Preliminary characterization of the microbial phylogeny and metabolic potential of a deep-sea sediment sample from the Qiongdongnan Basin, South China Sea, was carried out using a metagenomic library approach. An effective and rapid method of DNA isolation, purification, and library construction was used resulting in approximately 200,000 clones with an average insert size of about 36 kb. End sequencing of 600 individual clones from the fosmid library generated 1,051 sequences with an average sequence length of 619 bp. Phylogenetic ascription indicated that this library was dominated by Bacteria, predominantly Proteobacteria, though Planctomycetes were also relatively abundant. Sulfate-reducing and anaerobic ammonium-oxidizing bacteria, which play important roles in the cycling of sedimentary nutrients, were abundant in the library. Cluster of orthologous groups category analysis showed that most of the genes contained in the end sequences were related to metabolism, and with cellular processes and signaling. Functional groups assigned by SEED (subsystems-based annotations) highlighted the existence of 'one-carbon' metabolism within this community as well as identifying functional genes involved in methanogenesis. Furthermore, diverse genes involved in the biodegradation of xenobiotics were found using Kyoto Encyclopedia of Genes and Genomes metabolic pathway analysis.

  8. Controls of asymmetrical opening on rift and sag basins of South Atlantic conjugate margins: Insights from gravity transects and mapping using grids of seismic reflection data

    NASA Astrophysics Data System (ADS)

    Loureiro, P.; Mann, P.

    2015-12-01

    A recent model by Brune et al. (2014) explains the asymmetrical, conjugate margins of the South Atlantic as the result of passive rift migration with sequential normal faulting during early continental breakup. The onset of continental rifting in the South Atlantic began in the Valanginian about 138 Ma. Flood basalts - originating from the eruption of the Tristan Da Cunha plume on both conjugate margins - have been dated between 138-128 Ma and indicating a transition from passive rifting controlled by plate motions to active rifting controlled by a mantle plume. Using seven 2D gravity transects ranging from 200-1000 km in length, we identify variations in crustal thickness and depth to Moho for conjugate margins in Brazil and Angola. Low pass filters applied to a regional satellite derived gravity grid reveal now inactive, sequential normal faults. The modeled gravity transects refine the extent of hyperextended continental crust and allow for the identification of hanging-wall/ footwall relationships. For the Santos-Namibe conjugate margin, we propose that the Santos basin is the footwall of an asymmetrical rift system spanning a 200-km-wide zone and that the Namibe basin is the hanging wall with a 125-km-wide rift. For the Campos-Benguela conjugate margin 400 km to the north, we propose the Campos basin is the hanging wall with a 150-km-wide rift zone. Well data shows that a thicker carbonate sag basin (135- 325 m) and overlying salt basin (up to 2 km) are associated with the footwall blocks of Kwanza and Santos while thinner carbonate sag basins (15-75 m) and overlying salt (up to 1.5 km) are associated with hanging wall blocks in accord with model predictions for early opening.

  9. Modelling of INTER-Linkages Between LAND Cover Pattern and Socio-Economic Factors in the Idemili River Basin of South Eastern Nigeria

    NASA Astrophysics Data System (ADS)

    Maduekwe, N. I.; Adesina, F. A.

    2014-12-01

    This study explores the inter-relationships between socio-economic factors and land cover pattern in the Idemili River Basin of South Eastern Nigeria. It is based on the concept of coupled human environment systems and focuses on the modelling of community scale relationships between critical land cover parameter and socio-demographic, economic and cultural factors in the basin. The modelling was implemented with pixel level NDVI indicators of vegetation cover density developed from NigeriaSat image with 32m resolution linked to eight indicators of socio-economic factors developed from a household survey of the basin. NDVI and socio-economic data were matched for 25 sampled localities in the basin and their relationships modelled with correlation, regression and Principal Component Analysis statistics. NDVI based image analysis showed a high level of human impact on vegetation. The Model output shows that bivariate relationships between vegetation cover dynamics and socio-demographic variables were the most significant, with R Square values > 0.60 for linear and non linear models. Vegetation cover density has high inverse correlations with population, urbanization levels and number of households in localities. Population/urbanization status of localities was also the most significant Principal Component or underlying dimension linked to spatial dynamics of vegetation cover in the basin accounting for 50% of factor variations. Relationships between vegetation cover densities and economic factors (occupational and household energy patterns) and socio-cultural factors (environmental knowledge, values and governance) were weaker and less significant. The study captured the linkages between landcover- represented by vegetation cover- and socio-economic parameters. It demonstrates that socio-economic factors are major drivers of change in the basin. Key Words: Socio-economic factors, Vegetation Cover, NDVI, Socio-ecological Systems, State Variables, South Eastern Nigeria

  10. Investigation of the seasonal spatial variability of the Caspian Sea level by satellite altimetry.

    NASA Astrophysics Data System (ADS)

    Safarov, Elnur; Mammadov, Ramiz; Cretaux, Jean-Francois; Arsen, Adalbert; Safarov, Said; Amrahov, Elvin

    2016-07-01

    Sea level fluctuations are among the most outstanding and debated issues of the Caspian Sea. Precipitation, underground water and river input are consistent parts of the inflow of the Caspian Sea water balance. The river input is also considered to be the main driver of the seasonal level changes of the Caspian Sea. Sufficiently large amount of this input is provided by the Volga. Although there is a good network of sea level stations covering the coastline of the sea, these facilities are not capable to reflect the sea level variations over the all surface. Meanwhile, the Caspian Sea is well observed by satellites Jason 1, Jason 2 and ENVISAT. Altimetric data taken from these satellites covers the surface of the sea much better than the data from the in-situ network stations. In this paper we investigate the spatial variability of the sea level that could provide more insight into the influence of river input (especially the Volga river), precipitation and other hydro-meteorological parameters on the Caspian Sea level.The altimetric data was averaged per every 10 square kilometers through all the tracks by means of the pre-prepared program made especially for this work. Also new maps of seasonal spatial variability of amplitude and phase of the annual signal of the Caspian Sea level for each investigated satellite were created by employing ARCGIS software. Moreover, these peaks of sea level amplitude and phase of annual signal results were comparatively analyzed with the corresponding river discharge of the Volga.

  11. Holocene deposits in the Mangyshlak Peninsula, North Caspian Sea region

    NASA Astrophysics Data System (ADS)

    Bezrodnykh, Yu. P.; Deliya, S. V.; Romanyuk, B. F.; Fedorov, V. I.; Sorokin, V. M.; Luksha, V. L.

    2014-07-01

    Comprehensive analysis of the data of high-precision seismoacoustic profiling, drilling and sampling of deposits using seabed corers, biostratigraphic studies, and radiocarbon age data was performed for the first time for Mangyshlak sediments in several bottom sites of the North Caspian. It was found that the Mangyshlak sediments comprise numerous linearly stretched depressions of 5-10 m in depth (morphologically similar to modern substeppe ilmen areas in the Volga River delta), which are covered by the Novocaspian sedimentary cover, and river incisions (among them the largest Volga River valley). In addition, the Mangyshlak sediments comprise the deltaic alluvial fans of different sizes along the shelf zone of the North Caspian. Analysis of mollusks and biogenic remains indicates that accumulation of the Mangyshlak sediments occurred in freshwater and slightly salty water environments under various hydrodynamic and hydrochemical conditions. According to radiocarbon dating of organic matter, the Mangyshlak sediments formed during sea regression in the range of 10-8 ka (isotopic age) or 11.5-8.5 ka (calendar age). Several types of sediments are distinguished: clayey-carbonate sediments, enriched with organic matter up to the formation of sapropel and peat, accumulated at the lowest sea level; weakly calcareous silty-clayey silts, formed during the subsequent intense filling of paleodepressions with terrigenous material. The features of the mineral composition of sediments are as follows: polymineral composition of clayey material with a high proportion of hydromica and disordered mixed-layered formations, a high content of minerals of the epidote group, amphiboles, and other accessory minerals. All of this indicates a genetic relationship between the Mangyshlak sediments and the Volga terrigenous material.

  12. Ice in Caspian Sea and Aral Sea, Kazakhstan

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this MODIS image from December 3, 2001, winter sea ice can be seen forming in the shallow waters of the northern Caspian (left) and Aral (upper right) Seas. Despite the inflow of the Volga River (upper left), the northern portion of the Caspian Sea averages only 17 ft in depth, and responds to the region's continental climate, which is cold in winter and hot and dry in the summer. The southern part of the Sea is deeper and remains ice-free throughout the winter. The dirty appearance of the ice may be due to sediment in the water, but may also be due to wind-driven dust. The wind in the region can blow at hurricane-force strength and can cause the ice to pile up in hummocks that are anchored to the sea bottom. The eastern portion of the Aral Sea is also beginning to freeze. At least two characteristics of the Aral Sea 'compete' in determining whether its waters will freeze. The Sea is shallow, which increases the likelihood of freezing, but it is also very salty, which means that lower temperatures are required to freeze it than would be required for fresh water. With average December temperatures of 18o F, it's clearly cold enough to allow ice to form. As the waters that feed the Aral Sea continue to be diverted for agriculture, the Sea becomes shallower and the regional climate becomes even more continental. This is because large bodies of water absorb and retain heat, moderating seasonal changes in temperature. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  13. A Concept for a Long Term Hydrologic Observatory in the South Platte River Basin

    NASA Astrophysics Data System (ADS)

    Ramirez, J. A.

    2004-12-01

    The intersection between: (1) the Rocky Mountains and developments occurring in high altitude fragile environments; (2) the metropolitan areas emerging at the interface of the mountains and the plains; (3) the irrigation occurring along rivers as they break from the mountains and snake across the Great Plains; and (4) the grasslands and the dryland farming that covers the vast amount of the Great Plains, represents a dynamic, complex, highly integrated ecosystem, stretching from Montana and North Dakota to New Mexico and Texas. This swath of land, and the rivers that cross it (headwaters of the Missouri , the Yellowstone, the North Platte , the South Platte, the Arkansas , the Cimarron, the Red and the Pecos Rivers ), represent a significant percentage of the landmass of the United States. Within this large area, besides tremendous increases in population in metropolitan areas, there are new energy developments, old hard rock mining concerns, new recreation developments, irrigation farms selling water to meet urban demands, new in-stream flow programs, struggling rural areas, and continued "mining" of ground water. The corresponding impacts are creating endangered and threatened species conflicts which require new knowledge to fully understand the measures needed to mitigate harmful ecosystem conditions. Within the Rocky Mountain/Great Plains interface, water is limiting and land is plentiful, presenting natural resource managers with a number of unique problems which demand a scale of integrated science not achieved in the past. For example, water is imported into a number of the streams flowing east from the Rocky Mountains. Nitrogen is deposited in pristine watersheds that rise up high in the Rocky Mountains. Cities capture spring runoff in reservoirs to use at a steady rate over the entire year, putting water into river systems normally moving low flows in the winter. Irrigation of both urban landscapes and farm fields may be at a scale that impacts climate

  14. Petroleum systems of Zhu III depression in Pearl River Mouth Basin, South China Sea

    SciTech Connect

    Weilin, Zhu; Li Mingbi; Wu Peikang

    1996-12-31

    Zhu III depression is located in the west part of Pearl River Mouth Basin, and covers an area of 11,000 sq km. Until now more than twenty wells have been drilled in the depression and its surrounding area, and all oil-gas fields and oil-gas discoveries are concentrated inside the depression. Integrated study indicates that there are two petroleum systems in Zhu III depression. One is Wenchang - Zhuhai, Zhujiang oil system which is mainly distributed in Wenchang B sag in the southwest part of the depression. Its source rock, the Wenchang formation is mainly composed of dark mudstone of lacustrine facies, with thicknesses up to more than 1000 m. Its reservoir includes tidal sandstone of transitional facies of Zhuhai formation and neritic sandstone of the lower part of Zhujiang formation. Through bounding faults and margin coarse sediment zone, oil generated from the Wenchang formation migrated into overlying sandstone of Zhuhai formation, which was overlaid by mudstone beds of bay facies of Zhuhai formation or neritic facies of Zhujiang formation, and formed oil accumulations. The other system is Enping - Zhuhai gas system, distributed in Wenchang A sag in the northeast part of the depression, whose source rock in the Enping formation deposited in the contracting stage of the lake, dominated by swamp coal measure in lithology and terrestrial plant clastics in kerogen components. The gas generated from Enping formation directly migrated into overlying tidal sandstone of Zhuhai formation and formed gas accumulations. Therefore, exploration in Wenchang A sag in the northeast part of the depression is for gas accumulations, and oil accumulations in Wenchang B sag in the southwest part of the depression, while oil-gas mixed accumulations are likely to be found in the transitional area of two systems.

  15. Petroleum systems of Zhu III depression in Pearl River Mouth Basin, South China Sea

    SciTech Connect

    Weilin, Zhu; Li Mingbi; Wu Peikang )

    1996-01-01

    Zhu III depression is located in the west part of Pearl River Mouth Basin, and covers an area of 11,000 sq km. Until now more than twenty wells have been drilled in the depression and its surrounding area, and all oil-gas fields and oil-gas discoveries are concentrated inside the depression. Integrated study indicates that there are two petroleum systems in Zhu III depression. One is Wenchang - Zhuhai, Zhujiang oil system which is mainly distributed in Wenchang B sag in the southwest part of the depression. Its source rock, the Wenchang formation is mainly composed of dark mudstone of lacustrine facies, with thicknesses up to more than 1000 m. Its reservoir includes tidal sandstone of transitional facies of Zhuhai formation and neritic sandstone of the lower part of Zhujiang formation. Through bounding faults and margin coarse sediment zone, oil generated from the Wenchang formation migrated into overlying sandstone of Zhuhai formation, which was overlaid by mudstone beds of bay facies of Zhuhai formation or neritic facies of Zhujiang formation, and formed oil accumulations. The other system is Enping - Zhuhai gas system, distributed in Wenchang A sag in the northeast part of the depression, whose source rock in the Enping formation deposited in the contracting stage of the lake, dominated by swamp coal measure in lithology and terrestrial plant clastics in kerogen components. The gas generated from Enping formation directly migrated into overlying tidal sandstone of Zhuhai formation and formed gas accumulations. Therefore, exploration in Wenchang A sag in the northeast part of the depression is for gas accumulations, and oil accumulations in Wenchang B sag in the southwest part of the depression, while oil-gas mixed accumulations are likely to be found in the transitional area of two systems.

  16. Sediment Quality and Comparison to Historical Water Quality, Little Arkansas River Basin, South-Central Kansas, 2007

    USGS Publications Warehouse

    Juracek, Kyle E.; Rasmussen, Patrick P.

    2008-01-01

    The spatial and temporal variability in streambed-sediment quality and its relation to historical water quality was assessed to provide guidance for the development of total maximum daily loads and the implementation of best-management practices in the Little Arkansas River Basin, south-central Kansas. Streambed-sediment samples were collected at 26 sites in 2007, sieved to isolate the less than 63-micron fraction (that is, the silt and clay), and analyzed for selected nutrients (total nitrogen and total phosphorus), organic and total carbon, 25 trace elements, and the radionuclides beryllium-7, cesium-137, lead-210, and radium-226. At eight sites, streambed-sediment samples also were collected and analyzed for bacteria. Particulate nitrogen, phosphorus, and organic carbon concentrations in the streambed sediment varied substantially spatially and temporally, and positive correlations among the three constituents were statistically significant. Along the main-stem Little Arkansas River, streambed-sediment concentrations of particulate nitrogen and phosphorus generally were larger at and downstream from Alta Mills, Kansas. The largest particulate nitrogen concentrations were measured in samples collected in the Emma Creek subbasin and may be related to livestock and poultry production. The largest particulate phosphorus concentrations in the basin were measured in samples collected along the main-stem Little Arkansas River downstream from Alta Mills, Kansas. Particulate nitrogen, phosphorus, and organic carbon content in the water and streambed-sediment samples typically decreased as streamflow increased. This inverse relation may be caused by an increased contribution of sediment from channel-bank sources during high flows and (or) increased particle sizes transported by the high flows. Trace element concentrations in the streambed sediment varied from site to site and typically were less than threshold-effects guidelines for possible adverse biological effects

  17. Groundwater-Quality Data in the South Coast Interior Basins Study Unit, 2008: Results from the California GAMA Program

    USGS Publications Warehouse

    Mathany, Timothy M.; Kulongoski, Justin T.; Ray, Mary C.; Belitz, Kenneth

    2009-01-01

    Groundwater quality in the approximately 653-square-mile South Coast Interior Basins (SCI) study unit was investigated from August to December 2008, as part of the Priority Basins Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basins Project was developed in response to Legislative mandates (Supplemental Report of the 1999 Budget Act 1999-00 Fiscal Year; and, the Groundwater-Quality Monitoring Act of 2001 [Sections 10780-10782.3 of the California Water Code, Assembly Bill 599]) to assess and monitor the quality of groundwater used as public supply for municipalities in California, and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). SCI was the 27th study unit to be sampled as part of the GAMA Priority Basins Project. This study was designed to provide a spatially unbiased assessment of the quality of untreated groundwater used for public water supplies within SCI, and to facilitate statistically consistent comparisons of groundwater quality throughout California. Samples were collected from 54 wells within the three study areas [Livermore, Gilroy, and Cuyama] of SCI in Alameda, Santa Clara, San Benito, Santa Barbara, Ventura, and Kern Counties. Thirty-five of the wells were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 19 were selected to aid in evaluation of specific water-quality issues (understanding wells). The groundwater samples were analyzed for organic constituents [volatile organic compounds (VOCs), pesticides and pesticide degradates, polar pesticides and metabolites, and pharmaceutical compounds], constituents of special interest [perchlorate and N-nitrosodimethylamine (NDMA)], naturally occurring inorganic constituents [trace elements, nutrients, major and minor ions, silica, total dissolved solids (TDS), and alkalinity

  18. Flood Inundation Analysis Considering Mega Floods in PyeonChang River Basin of South Korea

    NASA Astrophysics Data System (ADS)

    Kim, D.; Han, D.; Choi, C.; Lee, J.; Kim, H. S.

    2015-12-01

    Recently, abnormal climate has frequently occurred around the world due to global warming. In South Korea, more than 90% of damage due to natural disasters has been caused by extreme events like strong wind and heavy rainfall. Most studies regarding the impact of extreme events on flood damage have focused on a single heavy rainfall event. But several heavy rainfall events can be occurred continuously and these events will affect occurring huge flood damage. This study explores the impact of the continuous extreme events on the flood damage. Here we call Mega flood for this type of flood which is caused by the continuous extreme events. Inter Event Time Definition (IETD) method is applied for making Mega flood scenarios depending on independent rainfall event scenarios. Flood inundations are estimated in each situation of the Mega flood scenarios and the flood damages are estimated using a Multi-Dimensional Flood Damage Analysis (MD-FDA) method. As a result, we expect that flood damage caused by Mega flood leads to much greater than damage driven by single rainfall event. The results of this study can be contributed for making a guideline and design criteria in order to reduce flood damage.This work was supported by the National Research Foundation of Korea (NRF) and grant funded by the Korean government (MEST; No. 2011-0028564).

  19. The formation of deep basins in High Arctic from metamorphism in continental crust

    NASA Astrophysics Data System (ADS)

    Artyushkov, Eugene; Belyaev, Igor; Chekhovich, Peter; Petrov, Eugene; Poselov, Viktor

    2014-05-01

    In the East Barents and North Chukchi basins, 16-20 km deep, the crystalline crust is attenuated to 12-18 km (reference profiles 2-AR, 4-AR and 5-AR). P-wave velocities and densities in this layer are characteristic of the oceanic crust. However, the subsidence history in the basins is quite different from that typical of the oceanic crust. In both basins the subsidence continued for several hundred million years and one half of the deposits or more was formed long after the start of the subsidence when cooling of the oceanic plate would be already over. Moreover, the basins are 4-5 km deeper than it could be expected according to the thickness of the crystalline crust above the Moho boundary. In the absence of large free-air gravity anomalies, joint analysis of the gravity and seismic data indicates the existence under the Moho of thick layers of high-density and high-velocity eclogites. As can be seen in high resolution seismic profiles, the intensity of crustal stretching did not exceed 10% in the basins, and their formation can be predominantly attributed to a high-grade metamorphism in the mafic lower part of continental crust. At some episodes, strong increase in the rate of subsidence occurred in the basins. This indicates acceleration of metamorphism catalyzed by infiltration of mantle fluids. A set of the above features, abnormally large depth, long subsidence history with its acceleration at the late stages, and episodes of pronounced acceleration of the subsidence represent characteristic features of some other large hydrocarbon basins, e.g., of the North and South Caspian basins. These features can be used for prospecting new prolific provinces on the Arctic shelf. The Lomonosov ridge, Mendeleev high and the Makarov basin pertain to the same structural type. In the Oligocene they underwent erosion near to sea level with the formation of pronounced unconformity. Then at the end of Oligocene deep-water basins were formed in these regions. Rapid crustal

  20. Part I: Neoacadian to Alleghanian foreland basin development and provenance in the central appalachian orogen, pine mountain thrust sheet Part II: Structural configuration of a modified Mesozoic to Cenozoic forearc basin system, south-central Alaska

    NASA Astrophysics Data System (ADS)

    Robertson, Peter Benjamin

    Foreland and forearc basins are large sediment repositories that form in response to tectonic loading and lithospheric flexure during orogenesis along convergent plate boundaries. In addition to their numerous valuable natural resources, these systems preserve important geologic information regarding the timing and intensity of deformation, uplift and erosion history, and subsidence history along collisional margins, and, in ancient systems, may provide more macroscopic information regarding climate, plate motion, and eustatic sea level fluctuations. This thesis presents two studies focused in the Paleozoic Appalachian foreland basin system along the eastern United States and in the Mesozoic to Cenozoic Matanuska forearc basin system in south-central Alaska. Strata of the Appalachian foreland basin system preserve the dynamic history of orogenesis and sediment dispersal along the east Laurentian margin, recording multiple episodes of deformation and basin development during Paleozoic time. A well-exposed, >600 m thick measured stratigraphic section of the Pine Mountain thrust sheet at Pound Gap, Kentucky affords one of the most complete exposures of Upper Devonian through Middle Pennsylvanian strata in the basin. These strata provide a window into which the foreland basin's development during two major collisional events known as the Acadian-Neoacadian and the Alleghanian orogenies can be observed. Lithofacies analysis of four major sedimentary successions observed in hanging wall strata record the upward transition from (1) a submarine deltaic fan complex developed on a distal to proximal prodelta in Late Devonian to Middle Mississippian time, to (2) a Middle to Late Mississippian carbonate bank system developed on a slowly subsiding, distal foreland ramp, which was drowned by (3) Late Mississippian renewed clastic influx to a tidally influenced, coastal deltaic complex to fluvial delta plain system unconformably overlain by (4) a fluvial braided river complex

  1. Low Angle Normal Fault System Controls the Structure Evolution of Baiyun Deepwater Basin and Its Lithosphere Thinning, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Ren, J.; Yang, L.

    2015-12-01

    The discovery of the transition area from ~30 km to weakly thinned continental crust (<12 km) in Baiyun deepwater basin, Northern South China Sea leads to two questions: What controls extreme crustal thinning and what is the nature of Baiyun basin. The 3D seismic data newly acquired show that Baiyun basin is an asymmetric half graben mainly controlled by a set of north-dipping normal faults converging in deep. By employing the principle of back-stripping, we estimate the fault dips and slip amount would be in the absence of post-rift sediments and seawater loading. Results show these Middle Eocene faults were extremely active, with a high accumulation horizontal displacement (> 10 km) and an initial very low angle (<7°), followed by a rotated into sub-horizontal. A general scenario for extension of the uppermost continental crust probably includes simultaneous operation of low angle normal fault (F1) as well as parallel arrays of step-faults (domino-faults, f2-f9). Under such a scenario, it shows no obvious extension discrepancy in Baiyun basin. Our results indicate that Baiyun sag preserves information recording the continent thinning before the seafloor spreading, and it could be an abandoned inner rifted basin.

  2. Continuous hydrologic simulation of runoff for the Middle Fork and South Fork of the Beargrass Creek basin in Jefferson County, Kentucky

    USGS Publications Warehouse

    Jarrett, G. Lynn; Downs, Aimee C.; Grace-Jarrett, Patricia A.

    1998-01-01

    The Hydrological Simulation Pro-gram-FORTRAN (HSPF) was applied to an urban drainage basin in Jefferson County, Ky to integrate the large amounts of information being collected on water quantity and quality into an analytical framework that could be used as a management and planning tool. Hydrologic response units were developed using geographic data and a K-means analysis to characterize important hydrologic and physical factors in the basin. The Hydrological Simulation Program FORTRAN Expert System (HSPEXP) was used to calibrate the model parameters for the Middle Fork Beargrass Creek Basin for 3 years (June 1, 1991, to May 31, 1994) of 5-minute streamflow and precipitation time series, and 3 years of hourly pan-evaporation time series. The calibrated model parameters were applied to the South Fork Beargrass Creek Basin for confirmation. The model confirmation results indicated that the model simulated the system within acceptable tolerances. The coefficient of determination and coefficient of model-fit efficiency between simulated and observed daily flows were 0.91 and 0.82, respectively, for model calibration and 0.88 and 0.77, respectively, for model confirmation. The model is most sensitive to estimates of the area of effective impervious land in the basin; the spatial distribution of rain-fall; and the lower-zone evapotranspiration, lower-zone nominal storage, and infiltration-capacity parameters during recession and low-flow periods. The error contribution from these sources varies with season and antecedent conditions.

  3. Quantity and location of groundwater recharge in the Sacramento Mountains, south-central New Mexico (USA), and their relation to the adjacent Roswell Artesian Basin

    NASA Astrophysics Data System (ADS)

    Rawling, Geoffrey C.; Newton, B. Talon

    2016-06-01

    The Sacramento Mountains and the adjacent Roswell Artesian Basin, in south-central New Mexico (USA), comprise a regional hydrologic system, wherein recharge in the mountains ultimately supplies water to the confined basin aquifer. Geologic, hydrologic, geochemical, and climatologic data were used to delineate the area of recharge in the southern Sacramento Mountains. The water-table fluctuation and chloride mass-balance methods were used to quantify recharge over a range of spatial and temporal scales. Extrapolation of the quantitative recharge estimates to the entire Sacramento Mountains region allowed comparison with previous recharge estimates for the northern Sacramento Mountains and the Roswell Artesian Basin. Recharge in the Sacramento Mountains is estimated to range from 159.86 × 106 to 209.42 × 106 m3/year. Both the location of recharge and range in estimates is consistent with previous work that suggests that ~75 % of the recharge to the confined aquifer in the Roswell Artesian Basin has moved downgradient through the Yeso Formation from distal recharge areas in the Sacramento Mountains. A smaller recharge component is derived from infiltration of streamflow beneath the major drainages that cross the Pecos Slope, but in the southern Sacramento Mountains much of this water is ultimately derived from spring discharge. Direct recharge across the Pecos Slope between the mountains and the confined basin aquifer is much smaller than either of the other two components.

  4. Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean.

    PubMed

    Resing, Joseph A; Sedwick, Peter N; German, Christopher R; Jenkins, William J; Moffett, James W; Sohst, Bettina M; Tagliabue, Alessandro

    2015-07-01

    Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.

  5. Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Resing, Joseph A.; Sedwick, Peter N.; German, Christopher R.; Jenkins, William J.; Moffett, James W.; Sohst, Bettina M.; Tagliabue, Alessandro

    2015-07-01

    Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.

  6. Early Triassic conodonts of Jiarong, Nanpanjiang Basin, southern Guizhou Province, South China

    NASA Astrophysics Data System (ADS)

    Chen, Yanlong; Jiang, Haishui; Lai, Xulong; Yan, Chunbo; Richoz, Sylvain; Liu, Xiaodan; Wang, Lina

    2015-06-01

    Jiarong (Huishui County, Guizhou Province, South China) is a key locality for the study of the Early Triassic recovery after the end-Permian mass extinction. The size reduction of conodonts at the Smithian/Spathian transition was first documented in Jiarong, and it is also a locality that contributes to the documentation of the Early Triassic paleo-seawater temperatures. In the Jiarong sections, thirteen conodont zones were identified for the Early Triassic; in ascending order, they are Hindeodus parvus Zone, Hindeodus sosioensis Zone, Clarkina krystyni Zone, Neoclarkina discreta Zone, Neospathodus cristagalli-Eurygnathodus costatus assemblage zone, Novispathodus waageni eowaageni Zone, Novispathodus waageni waageni Zone, Discretella discreta Zone, Pachycladina-Parachirognathus assemblage zone, Novispathodus pingdingshanensis Zone, Icriospathodus collinsoni Zone, Triassospathodus homeri Zone, Triassospathodus triangularis Zone. These conodont zones in the Jiarong sections improve the global correlation of Early Triassic sections and also provide better regional age constraints in an area that is important for studies of recovery from the extinction. Based on the first appearance of Nv. waageni eowaageni, the Induan/Olenekian boundary is recognized at 3.6 m above the base of the Jiarong III Section. The dominance of blade-shaped (segminate) conodonts was replaced by gondola-shaped (segminiplanate) conodonts twice; the first time was in the late Griesbachian, and the second time was in the early Spathian. The dominance of segminiplanate conodonts probably indicates that the deeper seawater environment became more oxygenated during the late Griesbachian and early Spathian for short time intervals, as it is believed that the Griesbachian segminiplanate conodonts favored deeper oxygenated water habitats. A new genus, Spathogondolella gen. nov., and a new species, Spathogondolella jiarongensis sp. nov., have been recognized.

  7. Strain partitioning of the Red River fault system explains the initiation of the Yinggehai Basin in the northwest region of South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, X.; He, J.; Ding, L.; Gao, R.; Ai, C.; Wang, X.; Pan, Z.

    2012-12-01

    The NW-trending Yinggehai Basin (YGHB), located around the Red River fault system (RRFS) in the northwest area of South China Sea (SCS), is an important petroleum-bearing province and characterized by a maximum sedimentation thickness of up to 17 km, a strong upwelling of Moho at 22-23 km depth, an average heat flow of 86 mW/m2, and diapirs structure. The YGHB is suggested to be closely related to the crustal deformation associated with displacements of the RRFS and the formation of the SCS, but the basin differs in its formation from the NE-trending Pearl River Mouth Basin and Qingdongnan Basin on the northern continental margin of SCS and the Yuanjiang Basin and Midu Basin along the RRFS. Based on a first-order estimate of the rheology and boundary condition of the YGHB, we developed a 2.5 dimensional finite element model to investigate the origin of the YGHB and the relationships between motions on the RRFS and the spreading of the SCS. The crustal rheology is simplified as an elasto-plastic upper crust and a visco-elastic lower crust. Possible lateral variations of viscosity in the lower crust are tested according to the tectonic setting of the basin region. Results show that associated with the regional crustal movements, deformation of the RRFS could be responsible for upper crustal extension on both its sides. Further, the style of extensional faulting around the RRFS is largely controlled by the rheology of the lower crust. This means that strain partitioning induced both by the transtensional loading of strike-slip fault system and by the lateral changes in rheology of the lower crust can result in normal faulting on both sides near the RRFS, and may be involved in the formation of the YGHB.

  8. Formation of South Pole-Aitken Basin as the Result of an Oblique Impact: Implications for Melt Volume and Source of Exposed Materials

    NASA Technical Reports Server (NTRS)

    Petro, N. E.

    2012-01-01

    The South Pole-Aitken Basin (SPA) is the largest, deepest, and oldest identified basin on the Moon and contains surfaces that are unique due to their age, composition, and depth of origin in the lunar crust [1-3] (Figure 1). SPA has been a target of interest as an area for robotic sample return in order to determine the age of the basin and the composition and origin of its interior [3-6]. As part of the investigation into the origin of SPA materials there have been several efforts to estimate the likely provenance of regolith material in central SPA [5, 6]. These model estimates suggest that, despite the formation of basins and craters following SPA, the regolith within SPA is dominated by locally derived material. An assumption inherent in these models has been that the locally derived material is primarily SPA impact-melt as opposed to local basement material (e.g. unmelted lower crust). However, the definitive identification of SPA derived impact melt on the basin floor, either by remote sensing [2, 7] or via photogeology [8] is extremely difficult due to the number of subsequent impacts and volcanic activity [3, 4]. In order to identify where SPA produced impact melt may be located, it is important to constrain both how much melt would have been produced in a basin forming impact and the likely source of such melted material. Models of crater and basin formation [9, 10] present clear rationale for estimating the possible volumes and sources of impact melt produced during SPA formation. However, if SPA formed as the result of an oblique impact [11, 12], the volume and depth of origin of melted material could be distinct from similar material in a vertical impact [13].

  9. Seismic Characteristics and Evolution of Intrusion in Qiongdongnan Basin: Implications for the Rifting of South China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Ren, J.; Yang, L.; Huang, C.

    2014-12-01

    The South China Sea (SCS) formed by magma-poor rifting in the Paleogene. The Qiongdongnan basin (QDNB) located at the north margin was thought to completely lack magma activities. Due to the limited amount of deepwater drills, magmas in deepwater area had been ignored in petroleum exploration, and thus our knowledge of basin analysis is far from complete. Based on a comprehensive study on seismic profiles and P wave velocity data, 12 intrusion-related seismic reflection anomalies in QDNB have been recognized. In the southwest of QDNB, gas chimneys and gas clouds have been found with a low velocity (<3.4 km/s). In the center area, the intensively deformed strata passing towards the diapir flanks suggest the existence of magma diapirs. However, the velocity within diapirs is neither too high nor too low (3.7-4.6 km/s), and there has been no obvious magnetic anomaly or gravity anomaly be found. Previous researches prove that the temperatures of the crustal melt layers at the time that the basalt solidifies are high (900-950 °C) so that the process can produce magmas representing large degrees of partial fusion of the crust. To judge from the evidence, in the center area these could be mixed magmas. Further east, the diapirs possess typical features of basaltic magma intrusions with a high seismic velocity (>6 km/s), a positive magnetic anomaly and a high gravity anomaly. In addition, according to different dips of marginal facies, three phases of diapirism can be identified (32 Ma, 15.5 Ma and 10.5 Ma). Along a narrow area with hyper-extended crust, those intrusions document the opening of SCS at 32 Ma and the volcanic activities afterwards. The results are corresponding to the fact that all of the intrusions in QDNB occurred during the extreme crustal thinning process and after the cessation of seafloor spreading, and thus the intrusion evolved with time would have major implications for post-rift emplacement.

  10. Organochlorine compounds in bed sediment and fish tissue in the South Platte River Basin, USA, 1992-1993

    USGS Publications Warehouse

    Tate, C.M.; Heiny, J.S.

    1996-01-01

    Bed-sediment and fish-tissue samples were collected in the South Platte River Basin to determine the occurrence and distribution of organochlorine compounds in the basin. During August-November 1992 and August 1993, bed sediment (23 sites) and fish tissue (subset of 19 sites) were sampled and analyzed for 32 organochlorine compounds in bed sediment and 27 compounds in fish tissue. More types of organochlorine compounds were detected in fish tissue than in bed sediment. Total DDT, p,p???-DDE, o,p???-DDE, p,p???-DDD, total PCS, Dacthal??, dieldrin, cis-chlordane, cis-nonachlor, trans-nonachlor, and p,p???-DDT were detected in fish tissue at >25% of the sites; p,p???-DDE, total DDT, cis-chlordane, and trans-chlordane were detected in bed sediment at >25% of the sites. Organochlorine concentrations in bed sediment and fish tissue were related to land-use settings. Few organochlorine compounds were detected at minimally impacted sites located in rangeland, forest, and built-up land-use settings. Chlordane-related compounds and p,p???-methoxychlor in bed sediment and fish tissue, endrin in fish tissue, and endosulfan I in bed sediment were associated with urban and mixed (urban and agricultural) sites. Dacthal?? in bed sediment and fish tissue was associated with agricultural sites. The compounds HCB, ??-HCH, PCA, and toxaphene were detected only at mixed land-use sites. Although DDT and DDT-metabolites, dieldrin, and total PCB were detected in urban, mixed, and agricultural land-use settings, highest mean concentrations were detected at mixed land-use sites. Mixed land-use sites had the greatest number of organochlorine compounds detected in fish tissue, whereas urban and mixed sites had the greatest number of organochlorine compounds detected in bed sediment. Measuring concentrations of organochlorine compounds in bed sediment and fish tissue at the same site offers a more complete picture of the persistence of organochlorine compounds in the environment and their

  11. A combined chemical, isotopic and microstructural study of pyrite from roll-front uranium deposits, Lake Eyre Basin, South Australia

    NASA Astrophysics Data System (ADS)

    Ingham, Edwina S.; Cook, Nigel J.; Cliff, John; Ciobanu, Cristiana L.; Huddleston, Adam

    2014-01-01

    The common sulfide mineral pyrite is abundant throughout sedimentary uranium systems at Pepegoona, Pepegoona West and Pannikan, Lake Eyre Basin, South Australia. Combined chemical, isotopic and microstructural analysis of pyrite indicates variation in fluid composition, sulfur source and precipitation conditions during a protracted mineralization event. The results show the significant role played by pyrite as a metal scavenger and monitor of fluid changes in low-temperature hydrothermal systems. In-situ micrometer-scale sulfur isotope analyses of pyrite demonstrated broad-scale isotopic heterogeneity (δ34S = -43.9 to +32.4‰VCDT), indicative of complex, multi-faceted pyrite evolution, and sulfur derived from more than a single source. Preserved textures support this assertion and indicate a genetic model involving more than one phase of pyrite formation. Authigenic pyrite underwent prolonged evolution and recrystallization, evidenced by a genetic relationship between archetypal framboidal aggregates and pyrite euhedra. Secondary hydrothermal pyrite commonly displays hyper-enrichment of several trace elements (Mn, Co, Ni, As, Se, Mo, Sb, W and Tl) in ore-bearing horizons. Hydrothermal fluids of magmatic and meteoric origins supplied metals to the system but the geochemical signature of pyrite suggests a dominantly granitic source and also the influence of mafic rock types. Irregular variation in δ34S, coupled with oscillatory trace element zonation in secondary pyrite, is interpreted in terms of continuous variations in fluid composition and cycles of diagenetic recrystallization. A late-stage oxidizing fluid may have mobilized selenium from pre-existing pyrite. Subsequent restoration of reduced conditions within the aquifer caused ongoing pyrite re-crystallization and precipitation of selenium as native selenium. These results provide the first qualitative constraints on the formation mechanisms of the uranium deposits at Beverley North. Insights into

  12. Seismic interpretation of the post-Middle Miocene section of the northeastern Northern South Sea Yellow Basin, Yellow Sea

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonju; Lee, Gwang H.; Kim, Han J.; Yi, BoYeon

    2016-04-01

    The Yellow Sea is a very shallow (< 90 m), semi-enclosed epicontinental sea, lying between China and the Korean Peninsula. The Yellow Sea has undergone gradual, regional subsidence since the Middle Miocene when the major plate reorganization in East Asia led to regional uplift and subsequent erosion in many parts of the marginal basins of the western Pacific, including the Yellow Sea. In this study, we analyzed about 2500 km of 2-D multi-channel seismic data from the northeastern part of the Northern South Yellow Sea Basin to investigate the post-Middle Miocene geologic history of the area. We identified and mapped the Middle Miocene unconformity (MMU) and two horizons (H1 and H2) which are correlatable over much of the area. H1 and H2 were inferred to be of the early Late Miocene (ca. 10 Ma) and of the late Late Miocene (ca. 6.7 Ma), respectively, assuming a constant sediment accumulation rate. MMU forms the top of the basement except for the southwestern corner of the area and is interrupted by numerous volcanic bodies, suggesting active post-Middle Miocene volcanism. The volcanic bodies are oriented largely parallel to the basement faults. H1 and H2 are also affected by volcanic bodies in the northern part of the area, suggesting continued volcanism until the late Late Miocene. The depth of MMU increases southwestward from about 250 m to over 750 m, indicating progressive tilting (i.e., differential subsidence) of the basement toward the depocenter in the southwest. The depths of H1 and H2 increase west- and southwestward from about 200 m to over 450 m and from about 150 m to over 300 m, respectively. Detailed seismic facies were not analyzed due to poor data quality; nevertheless, continuous reflectors, suggesting uniform and thus marine deposition, appear to increase upward and northeastward. This, together with the amount of subsidence estimated from the depth of MMU, strongly suggests that subsidence has been dominant in the area over the global sea

  13. Rock Magnetic Properties of the Latest Permian to Earliest Triassic Beaufort Group, Tweefontein area, Karoo Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Lycka, B.; Geissman, J. W.; Gastaldo, R.; Neveling, J.

    2013-12-01

    Over the past decade, terrestrial records of the end Permian mass extinction have received increased attention to better understand the absolute age of these deposits and their synchronicity with their marine counterparts. One of the best preserved terrestrial records of the Permian-Triassic boundary (PTB) is in the Eastern Cape of the Karoo Basin of South Africa. Study of the rock magnetic properties of Beaufort Group strata deposited across the vertebrate-defined PTB (Palingkloof member of the Balfour Formation and Katberg Formation) is part of an ongoing investigation to better understand the magnetic polarity stratigraphy across the PTB in the Karoo Basin. The definition of a magnetic polarity stratigraphy in these strata is predicated on the recognition of primary or early-acquired magnetizations. However, almost the entire region where Permian and Lower Triassic strata crop out is intruded by Early Jurassic (ca. 186-183 Ma) Karoo sills and related rocks, whose remanence is almost exclusively of normal polarity. Preliminary paleomagnetic results from the Tweefontein area (West Lootsberg Pass) suggest that Beaufort Group strata are overprinted by a normal polarity remanence similar in direction to Karoo sills sampled in a regional context. To better characterize the remanence in these rocks and assess the preservation of a primary remanence, a systematic rock magnetic stratigraphy is being obtained from a nearly continuously exposed, sub-horizontal section (~150 m) of upper Permian (Elandberg and Palingkloof members of the Balfour Formation) to lower Triassic strata (Katberg Formation) Preliminary anisotropy of magnetic susceptibility (AMS) data shows that a well-developed sedimentary fabric is preserved, with K3 directions near vertical and of low dispersion (e.g., decl/inc [confid estimates] 170/77 [ 5.1/4.1]; 228/85 [7.2/3.5] and 164/84 [9.3/3.0]). In general, bulk magnetic susceptibility data group at ~2.3x10-4 or ~4.8x10-4 SI volume and do not suggest

  14. Fast Deposition of Small River Particles on the NE South China Sea Slope Basin Since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Lin, S.; Cheng, W. Y.; Hsieh, I. C.

    2015-12-01

    Huge quantities of small rivers derived suspended particles are exporting to the ocean from oceanic islands at the present time. Depending on location and proportion of shelf/slope area, a major fraction of small river particles may by-pass the shelf region, transport and deposit on the deep ocean basin. Major mechanisms driving those huge quantities of small river derived particles to the ocean are quantity of precipitation from monsoon and those from short period of tropical cyclone. Although data demonstrate that deeper part of the South China Sea, SCS, is the major final burial location of the river derived particles from the island of Taiwan, it is not sure if this was the same during the glaciation when monsoon and climatic conditions were drastic different from the present time. The purpose of this study is to understand history of small river derived sediment export and deposition during climatic change. A long piston core with length of ~35 meter was taken on r/v Marion DuFresne on a slope basin offshore SW Taiwan. We have measured density, magnetic susceptibility with multi-sensor core logger, MSCL, and organic, inorganic carbon, C/N ratio, biogenic silica as well as grain sizes. Foraminifera (Orbulina universa, Globigerinoides sacculifer and Globigerinoides conglobatus) were picked and measured carbon 14 for age determination. Two different types of processes control sediment deposition in our study site, steady state and event driven sedimentation. Our results demonstrated that sedimentation rates were consistent during each major periods, the Holocene (present to 10k year) and the transition (10-20 k year) period, but, difference existed in between the two. Sedimentation rate was about twice faster during the transition period (20-10k year) than that at the Holocene (10-present time) at our study site. A number of spikes existed in our study site, probably a result of turbidite overflow from the adjacent canyon. Frequency and total thickness of event

  15. An integrated modelling framework to aid smallholder farming system management in the Olifants River Basin, South Africa

    NASA Astrophysics Data System (ADS)

    Magombeyi, M. S.; Taigbenu, A. E.

    Computerised integrated models from science contribute to better informed and holistic assessments of multifaceted policies and technologies than individual models. This view has led to considerable effort being devoted to developing integrated models to support decision-making under integrated water resources management (IWRM). Nevertheless, an appraisal of previous and ongoing efforts to develop such decision support systems shows considerable deficiencies in attempts to address the hydro-socio-economic effects on livelihoods. To date, no universal standard integration method or framework is in use. For the existing integrated models, their application failures have pointed to the lack of stakeholder participation. In an endeavour to close this gap, development and application of a seasonal time-step integrated model with prediction capability is presented in this paper. This model couples existing hydrology, agronomy and socio-economic models with feedbacks to link livelihoods of resource-constrained smallholder farmers to water resources at catchment level in the semi-arid Olifants subbasin in South Africa. These three models, prior to coupling, were calibrated and validated using observed data and participation of local stakeholders. All the models gave good representation of the study conditions, as indicated by the statistical indicators. The integrated model is of general applicability, hence can be extended to other catchments. The impacts of untied ridges, planting basins and supplemental irrigation were compared to conventional rainfed tillage under maize crop production and for different farm typologies. Over the 20 years of simulation, the predicted benefit of untied ridges and planting basins versus conventional rainfed tillage on s