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Sample records for south caspian basin

  1. 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

  2. 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.

  3. 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

  4. The reefal margin of the south Caspian basin and its petroleum prospects (Southwestern Turkmenia). [USSR

    SciTech Connect

    Grachevskiy, M.M.; Kucheruk, Y.V.; Skvortsov, I.A.; Zyubko, A.K.

    1982-07-01

    By analogy with the extremely rich Mexican petroliferous barrier-reef La Reforma trend, and on the basis of a paleogeomorphic analysis of geologic-geophysical data, the reefal edge of the South Caspian Basin of Neocomian age has been recognized in Southwestern Turkmenia; this is promising with respect to oil and gas exploration in combined (structural-reefal) traps. The extent of the reefal scarp is about 400 km in the terrestrial part, with an amplitude of up to 1500-2000 m, the width of the crest is about 5 km, and the depth of occurrence is 3000-4500 m. In its sublatitudinal part, the reef coincides with the Near-Balkhan zone of structures, productive in the Pliocene sequence. In its submeridional part, it corresponds to the so-called Shordzha-Gekcha fault and has been built over by a Cretaceous diapiric clay swell. The paleogeomorphic plan in the South Caspian petroliferous basin, apart from Southwestern Turkmenia, suggests the distribution of the marginal barrier-reef scarp beyond the water area of the Caspian Sea and the Kura Basin.

  5. Fundamental challenges of the location of oil and gas in the South Caspian Basin

    NASA Astrophysics Data System (ADS)

    Guliev, I. S.; Kerimov, V. Yu.; Mustaev, R. N.

    2016-11-01

    Subvertical and subhorizontal bodies were identified in the South Caspian Basin. They are a new class of geological structures with a complicated form, which can serve as migration pathways and hydrocarbon accumulation zones. The basin incorporates a few autonomous sources of oil and gas occurrences with their own distribution areas and spatial-temporal evolution. HC generation sources are displaced relative to each other. The lower boundary of the oil and gas occurrence reaches depths of more than 12-15 km, while the upper boundary of the "oil window" is confined to hypsometric depths of 5-7 km.

  6. 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.

  7. 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

  8. Ejected Sedimentary Rocks of Mud Volcanoes as Indicators of Depositional Environments and of Hydrocarbon Generation within the South Caspian Basin, Azerbaijan

    NASA Astrophysics Data System (ADS)

    Berner, U.; Scheeder, G.; Kus, J.; Köthe, A.; Movsumova, U.

    2009-04-01

    Mud volcanoes are prominent geological features of the South Caspian Basin of Azerbaijan, one of the oldest oil producing regions worldwide. The basin is characterized by extreme sedimentation rates, which lead to the accumulation of large volumes of Mesozoic and Cenozoic sediments. These mostly unconsolidated strata reach thicknesses of up to 20 km and overlay a continental basement in the onshore part. Tectonic forces control the occurrences of mud volcanoes in regions with over-pressured subsurface sediments as mud volcanoes are closely linked to fault systems. The mud volcanoes of Azerbaijan are a surface expression of vertical hydrocarbon migration and offer the chance to investigate the subsurface by means of ejected rocks transported to the surface. These rocks of Mesozoic and Cenozoic sedimentary sequences are potential indicators of the regional hydrocarbon generation. The mud of nineteen volcano cones contained numerous ejected rock fragments, which we use to identify environmental and depositional parameters of the sediments of the Caspian Basin. We also intended to estimate the depth range from which the mud was transported to the surface using organic geochemical parameters. Mircopalaeontological investigations (calcareous nannoplankton) have been performed on selected samples. These analyses suggest that the investigated sediments are of Late Cretaceous to Palaeogene ages and relate to the stratigraphic interval during which the main hydrocarbon source rocks of Azerbaijan have been deposited. Organic geochemical, organic petrographical and mircopalaeontological investigations have been performed on selected samples of nineteen mud volcanoes. Analyses total organic carbon and total sulphur were performed on an elemental analyzer. These analyses suggest that the sediments can be classified as anoxic marine deposits whereas only few are sediments of a lacustrine environment. Bulk source rock information were obtained from RockEval pyrolysis. Resulting

  9. Contribution to the molecular systematics of the genus Capoeta from the south Caspian Sea basin using mitochondrial cytochrome b sequences (Teleostei: Cyprinidae)

    PubMed Central

    Zareian, Halimeh; Esmaeili, Hamid Reza; Heidari, Adeleh; Khoshkholgh, Majid Reza; Mousavi-Sabet, Hamed

    2016-01-01

    Traditionally, Capoeta populations from the southern Caspian Sea basin have been considered as Capoeta capoeta gracilis. Study on the phylogenetic relationship of Capoeta species using mitochondrial cytochrome b gene sequences show that Capoeta population from the southern Caspian Sea basin is distinct species and receive well support (posterior probability of 100%). Based on the tree topologies obtained from Bayesian and Maximum Likelihood methods, three main groups for the studied Capoeta were detected: Clade I) Capoeta trutta group (the Mesopotamian Capoeta group) including closely related taxa (e.g. trutta, turani, barroisi) characterized by having numerous irregular black spots on the dorsal half of the body. This clade was the sister group to all other Capoeta species and its separation occurred very early in evolution possess, so we considered it as O ld Evolutionary Group. Clade II) comprises highly diversified and widespread group, Capoeta damascina complex group (small scale capoeta group), the Anatolian-Iranian group (e.g. banarescui, buhsei, damascina, saadii), characterized by small scales and plain body (absence of irregular black spots on the dorsal half of the body, except in some juveniles) with significantly later speciation event so called Young Evolutionary Group. Clade III) Capoeta capoeta complex group (large scale capoeta group, the Aralo-Caspian group) comprises very closely related taxa characterized by large scales and plain body (absence of irregular black spots on the dorsal half of the body) distributed in Aralo-Caspian water bodies (capoeta, ekmekciae, heratensis, gracilis, sevangi) that has been recently diverged and could be considered as Very Young Evolutionary Group. PMID:28097160

  10. Regional correlations in the South Caspian Sea -implications for stratigraphic nomenclature

    SciTech Connect

    Murphy, J. Rukhsara, K.

    1995-08-01

    Regional Correlations in the South Caspian Sea - Implications for Stratigraphic Nomenclature Detailed sequence boundary correlations in the South Caspian sea have led to a better understanding of the relationships between stratigraphic units identified in wells throughout the basin. With the aid of synthetic seismograms, used to tie the logs to the seismic data, lithologic units have been identified seismically and have been mapped across the basin. The synthetic seismograms were created from pseudo-sonic logs which were transformed from resistivity logs with the Faust equation. Checkshots and VSP surveys supplied the velocity control. The sequence boundary correlations revealed substantial facies changes across the basin and led to the creation of a new stratigraphic correlation chart which relates local formation names to their time correlative boundaries. A recognition of these facies changes has led to a better understanding of the lithologic relationships within the basin, the depositional history of the basin, and the source and distribution of potential reservoir sands. Previous well log correlations, made primarily by matching tops of sand and shale sequences, frequently crossed sequence boundaries mapped from seismic data. Lithologic units, deposited under similar geologic conditions, often looked the same but were not time equivalent. Seismic sequence analyses have shown that tectonic movements, as evidenced by rising domes, created barriers to sediment distribution and led to pronounced thickness changes on opposite sides of a high. New log correlations, incorporating these concepts, are helping to unravel the complex structural and stratigraphic history of the South Caspian Sea.

  11. 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

  12. 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

  13. 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

  14. 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.

  15. Geodynamical Nature of the Formation of Large Plates of Platforms, Jointed in North Caspian Oil and Gas Basin

    ERIC Educational Resources Information Center

    Seitov, Nassipkali; Tulegenova, Gulmira P.

    2016-01-01

    This article addresses the problems of tectonic zoning and determination of geodynamical nature of the formation of jointed tectonic structures within the North Caspian oil and gas basin, represented by Caspian Depression of Russian platform of East European Pre-Cambrian Craton and plate ancient Precambrian Platform stabilization and Turan…

  16. 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

  17. Responding to Environmental Challenges in Central Asia and the Caspian Basin

    DTIC Science & Technology

    2001-03-01

    cyanide spill that followed a tailings pond burst in Baia 1-13 Responding to Environmental Challenges in Central Asia and the Caspian Basin Mare ...Valdez Oil Spill Vice Admiral Clyde Robbins, USCG (Retired) Mozambique Floods Mr. L.J. Buys iii v ix xi 1-1 1-2 1-3 1-6 1-9 2-1 2-3 2-25...dimensions (Chapter 2). The Panel also examined case studies on the Exxon- Valdez Oil Spill and the Mozambique floods. The accepted definition of

  18. South American sedimentary basins

    SciTech Connect

    Urien, C.M.

    1984-04-01

    More than 64 sedimentary basins have been identified on the South American continent. According to their regional structural character and tectonic setting, they are classified in 4 super groups. About 20 interior or intracratonic basins occur on South American cratons (Guayanas, Brazilian, and Patagonian). In most cases, their sedimentary fill is Paleozoic or early Mesozoic. Rift or transverse grabens resulting from incipient sea floor spreading extend towards the continental margin. Seventeen basins are located along the Atlantic stable margin, and consist primarily of half grabens with downfaulted seaward blocks. These rifts (or pull-apart basins) were separated as results of the migration of the African and American continental blocks. Therefore the sedimentation is chiefly Cretaceous and Tertiary. On the western edge of South American cratons, almost 20 basins of downwarped blocks extend from Orinoco down to the Malvinas plateau in a relatively uninterrupted chain of retroarc basins, bordered by the Andean orogen. They lie on a flexured Precambrian and Paleozoic basement, and are highly deformed in the west (Subandean belt) due to the action of compressional forces caused by the tectonic influence of the Mesozoic Andean batholith. Westward, the Pacific margin is bordered by 27 foreland and forearc basins, which alternate from north to south on an unstable or quasistable margin, fringed by a trench and slope complex where the ocean crust is subducted beneath the continental plate.

  19. Active Tectonics of Western Turkmenistan; Implications for the Onset of South Caspian Subduction

    NASA Astrophysics Data System (ADS)

    Hollingsworth, J.; Jackson, J.; Priestley, K.

    2007-12-01

    The Kopeh Dagh and Balkan mountain ranges of West Turkmenistan are actively deforming as a result of Arabia- Eurasia collision. We combine observations of the geomorphology made from satellite and topographic data, with historical and recent seismicity to identify major active faults, and how they contribute to regional shortening. Between 55--57.5°E, partitioned (north-vergent) thrust and right-lateral strike-slip fault segments, comprising the Ashkabad fault zone, accommodate regional shortening and the westward-extrusion of the NW Kopeh Dagh-South Caspian block, relative to Central Iran and Eurasia. Reconstruction of displaced geology indicates 35~km total right-lateral motion across the Ashkabad fault zone. The Balkan region lies along-strike of the Ashkabad fault zone, west of 55°E. Fault plane solutions indicate shortening is partitioned onto the Balkan thrust and right-lateral Kum-Dagh fault zones. Thrust earthquakes are relatively deep (30--45~km) and lie along a north-dipping plane which extends 40±5~km north beneath the Balkan anticline. Receiver function data from Turkmenbashi and Nebit Dagh indicate these earthquakes occur in the base of the crust, and may therefore be related to bending of the NW Kopeh Dagh-South Caspian lithosphere as it is overthrust by Eurasia. Movement on a north-dipping blind thrust fault is consistent with the broad asymmetric (south-vergent) fold structure of the Balkan range. Recent uplift is also indicated by extensional faults which displace Quaternary geomorphology along the range crest. South of the Balkan range, right-lateral shear occurs across the Kum-Dagh fault zone which is expressed as a series of right-stepping anticlines (affecting Pliocene Red Series and younger sediments), forming important traps for hydrocarbons. An important structural change occurs near 55°E. To the west, Eurasia overthrusts the NW Kopeh Dagh- South Caspian block, while to the east the polarity of thrusting changes and the Kopeh Dagh

  20. Isotope composition (C, H, O) and gas potential assessment in the South Caspian depression (Azerbaijan)

    NASA Astrophysics Data System (ADS)

    Poletayev, A. V.

    2009-04-01

    The large amount of HC isotope composition material of over 330 samples allows to study gas potential assessment within the South Caspian depression. Maps of isotope composition changes according to area extent, as well as graphs of HC distribution depending upon stratigraphic age including rocks, graphs of isotope composition change on sampling depth were compiled for HC study and oil-gas deposits formation. Comparison of mud volcanoes gases, oil and gas fields, gas-hydrates and bottom sediments was conducted. Gases genesis according to M. Shoelle and A. James methodic was studied. Model of area paleoconstruction was studied. Comparison of mud volcanoes gases with gases of oil fields within South Caspian depression shows that their isotope composition varies within the same ranges. Their difference is observed in chemical composition. Mud volcanoes gases are sharply impoverished by amount of heavy hydrocarbons. Study of isotope gases composition distribution in extent area allowed to distinguish zones and areas with different composition of heavy isotope. For example, in the deep-seated areas of the South Caspian depression toward flank zones of Low Kura depression as well some areas of Baku archipelago and Absheron peninsula gradually one can observe zones with a low content of heavy carbon isotope etc. Isotope gases composition depending upon stratigraphic age of including rocks has a certain peculiarities. From low to the upper section of PS as well as deposits of Cretaceous system toward chokrak regiostage (underlying PS deposits) one can observe increase of light carbon isotope. This fact allows to suppose that there exits two stages of HC formation. Comparison of HC gases isotope composition with sampling depth allowed to conclude that in the near-flank zones oil-gas deposits were re-formed by a large gas volumes the source of which was there same deposits within new thermobaric conditions. Gases of biochemical, diagenetic and thermocatalytic genesis etc

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. Evaluating the efficiency of sediment metal pollution indices in interpreting the pollution of Haraz River sediments, southern Caspian Sea basin.

    PubMed

    Nasrabadi, Touraj; Bidhendi, Gholamreza Nabi; Karbassi, Abdolreza; Mehrdadi, Nasser

    2010-12-01

    The Haraz River is one of the most significant rivers in the southern Caspian Sea basin. Towards the estuary, the river receives discharges of industrial, agricultural, and urban wastes. In the present investigation, bulk concentrations of Cu, Zn, As, Cd, Pb, Fe, Ni, Cr, Co, and Sr in Haraz River (Iran) bed sediments were measured from several sample locations. In addition, association of studied metals with various sedimentary phases was assessed to determine the proportions of metals in different forms. The intensity of sediment contamination was evaluated using an enrichment factor (EF), geo-accumulation index (I(geo)), and a newly developed pollution index (I(poll)). Both EF and I(geo) formulae compare present concentrations of metals to their background levels in crust and shale, respectively. In a specific area with its own geological background like Haraz River water basin where naturally high concentrations of metals may be found, such a comparison may lead to biased conclusions regarding levels of anthropogenic contamination. Accordingly, chemical partitioning results are substituted for the mean crust and shale levels in the new index (I(poll)). The Pearson correlation coefficient between the anthropogenic portion of metallic pollution in Haraz river-bed sediments with I(poll) showed much more value in comparison with those of geochemical accumulation index and enrichment factor. The order of metals introduced by anthropogenic activities are as follows: Sr > Pb > Co > Cd > Zn > Cu > Ni > As > Cr > Fe. The results showed relatively higher concentrations of Cd, As, Sr, and Pb in comparison with those of shale. However, based on the chemical partitioning of metals, it is found that Sr, Pb, Co, and Cd are the most mobile metals. In spite of the high As concentrations in sediments, it is not likely that this element is a major hazard for the aquatic environment since it is found mainly in the residual fraction. Also, Fe, Cr, and Ni are present in the greatest

  7. 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.

  8. 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.

  9. 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.

  10. Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In this Moderate-resolution Imaging Spectroradiometer (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 feet 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 18oF, 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. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  11. 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.

  12. 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.

  13. South Pole-Aitken Basin Mission (SPAM)

    NASA Astrophysics Data System (ADS)

    Weitz, C. M.; Yingst, R. A.; Minitti, M.; Head, J. W., III; Prockter, L.; Dahl, J. M.; Cooper, C. D.; Crumpler, L.; Gershman, R.; Welch, R.; Jet Propulsion LABORATORY Team

    1997-03-01

    Recent Clementine data of the farside of the moon has shown high resolution details of the South Pole-Aitken basin. The basin is over 2500 km in diameter, making it the largest impact basin thus far identified in our solar system. Estimates for the excavation depth from the basin suggest that the lower crust/upper mantle may have been reached. Clementine UVVIS data show noritic compositions and high FeO wt pct compositions, supporting that at least the lower crust may have been excavated. Because the geology of the area offers a unique opportunity to study the stratigraphy of the lunar crust at depth as well as the composition of rocks from the lunar farside, we have selected a site in the South Pole-Aitken basin for a sample return mission. Although the mission described below is currently unsuitable as a Discovery class mission, other scenarios are still possible that will reduce the mass and make the mission more feasible.

  14. 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

  15. 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

  16. 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

  17. Zaliv Kara-Bogaz-Gol, Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The large eastern embayment of the Caspian Sea, the Zaliv Kara-Bogaz-Gol, provides astronauts the chance to observe several oceanographic phenomena. This view taken by the STS-111 crew from the Space Shuttle in June 2002 shows the sun reflecting off the surface waters that surround the spit that defines the Zaliv Kara-Bogaz-Gol from the open Caspian Sea. The sunglint reveals the flow of fresher water through the spit channel and into the bay. Old shorelines and accretionary features can be seen on the spit, as well as the dam that was constructed in 1980 to stop the flow into the lower Kara-Bogaz-Gol basin. The Caspian Sea has experienced dramatic changes in water levels throughout the past 100 years. From the 1930s until 1978, the water levels in the Caspian had dropped nearly 3 m. In 1980, in response to the rapidly dropping sea level, a dam was constructed to prevent water from flowing into the shallow and restricted Kara-Bogaz-Gol basin, resulting in the drying up of the bay. The dam was partially opened a few years later, and completely opened in 1992 when Caspian water levels started to rise quickly. Today, sea levels are more than 2.6 m higher than the 1978 levels, and, as shown here, water flows freely into the salty waters of the Zaliv Kara-Bogaz-Gol. Astronauts have also been documenting the coastlines around the Caspian Sea that have been impacted by the large sea level fluctuations. Astronaut photograph STS111-E-5485 was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  18. 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

  19. Power and Energy: Geopolitical Aspects of the Transnational Natural Gas Pipelines from the Caspian Sea Basin to Europe

    DTIC Science & Technology

    2010-06-01

    this strategy, the mountains —the Carpathians , the Caucasus and the Tien Shan—continue to play a key role. The Carpathians , which incorporate Ukraine...involved.”74 However, Kyrgyzstan has no strategic resources, but its importance to Russia lies in its geostrategic position. The Tien Shan Mountains in...Central Asia act as a natural barrier between Russia, and South Asia and China. Within the Tien Shan Mountains lies the core of Central Asia—the

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. The Caspian Sea Environment

    NASA Astrophysics Data System (ADS)

    Kostianoy, Andrey; Kosarev, A.

    The systematic description of the knowledge accumulated on the physical oceanography, marine chemistry and pollution, and marine biology of the Caspian Sea forms the basis of this book. It presents the principal characteristic features of the environmental conditions of the sea and their changes in the second half of the 20th century. At present, the principal problems of the Caspian Sea are related to the interannual sea level changes and their forecast and to the estimation of the intensity of the chemical pollution of the sea and its impact upon the biota.

  6. 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.

  7. Soekor, partners explore possibilities in Bredasdorp basin off South Africa

    SciTech Connect

    Burden, P.L.A. Ltd., Parow, )

    1992-12-21

    This paper reports on the Bredasdorp basin, situated off the south coast of the Republic of South Africa, southeast of Cape Town and west-southwest of Port Elizabeth. Both cities have modern deepwater harbor facilities. Infrastructure along the coast includes well developed road, air, and rail links. A petrochemical plant for the conversion of off-shore gas and condensate to hydrocarbon fuels as well as certain chemical feedstocks has recently been completed at Mossel Bay about 100 km north of the Bredasdorp basin. Refineries are situated at Cape Town and Durban.

  8. 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

  9. Isotope studies in the Caspian Sea.

    PubMed

    Froehlich, K; Rozanski, K; Povinec, P; Oregioni, B; Gastaud, J

    1999-09-30

    Oceanographic and isotopic investigations in the Caspian Sea and the analyses of the available data on the discharge to the sea and the observed sea level changes suggest that climatically caused changes of river inflow are the major cause of the sea level fluctuations over the last century. Hydrogen-3 and 3H-3He data indicate that the deep basins of the sea are rapidly ventilated, although the hydraulic turnover time of the sea is approximately 200 years. The concentration levels of the anthropogenic radionuclides 90Sr, 137Cs and 239,240Pu in the water column can be explained by global fallout and therefore, at the sampling sites visited, there were no signs of dumping of radioactive wastes. The anthropogenic radionuclide data support the idea of fast exchange of water masses in the Caspian Sea. The isotopic and oceanographic data collected during the cruises have shown potential to allow for a better understanding of the water circulation in the Caspian Sea.

  10. 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

  11. Petroleum Systems of South Kara Basin: 3D stratigraphic simulation and basin modeling results

    NASA Astrophysics Data System (ADS)

    Malysheva, S.; Vasilyev, V.; Verzhbitsky, V.; Ananyev, V.; Murzin, R.; Komissarov, D.; Kosenkova, N.; Roslov, Yu.

    2012-04-01

    Petroleum systems of South Kara Basin are still poorly studied and hydrocarbon resource estimates vary depending on geological models and understanding of the basin evolution. The main purpose of the regional studies of South Kara Basin was to produce a consistent model, which would be able to explain the existence of the fields discovered in the area as well as to determine the most favorable hydrocarbon accumulation zones in the study area for further exploration. In the study 3D stratigraphic simulation and basin modeling of South Kara Basin was carried out. The stratigraphic simulation results, along with geological, geophysical and geochemical data for the inland areas of Yamal and Gydan peninsulas and South Kara islands enabled to predict the lithological composition and distribution of source rocks, reservoirs and seals in the Kara Sea offshore area. Based on the basin modeling results hydrocarbon accumulations may occur in the reservoir facies of the wide stratigraphic range from Jurrasic to Cretaceous. The main source for the hydrocarbons, accumulated in the South Kara Basin Neocomian and Cenomanian reservoirs are the J3-K1 (the northward extension of Bazhenov Formation and its analogs of West Siberia), as well as J1 and probably J2 shales with predominantly marine type of kerogen (type II). Thermal and burial history restorations show that Lower Cretaceous (Aptian-Albian) sediments enriched with terrigenous organic matter (kerogen of type III) and containing coaly layers could not produce the hydrocarbon volumes to fill the giant Rusanovskoye and Leningradskoye gas-condensate fields as the K1 source rocks are not mature enough. The modeling results, in particular, suggest that the geologic conditions in the South Kara Basin are favorable for further discoveries of giant fields. Although gas accumulations are predominating in the basin, oil-and-gascondensate fields (not a pure oil fields though) with sufficient part of liquid hydrocarbons might be present

  12. 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.

  13. 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.

  14. What is the South Pole-Aitken basin hiding?

    NASA Astrophysics Data System (ADS)

    Garrick-Bethell, I.; Nimmo, F.; Wieczorek, M. A.

    2010-12-01

    The South Pole-Aitken (SP-A) basin is remarkable because of its great age, size, elliptical structure, and asymmetrical depth of excavation. Recent studies have elucidated its general shape (e.g. [1]), but questions still remain about what processes influenced the distribution of topography and crustal thickness inside the basin. There are emerging indications that SP-A may have impacted into a unique terrain, and that there is a remaining signature of that terrain imbedded in the details of the SP-A topography and crustal thickness. A recent study of the lunar farside highlands north of the basin [2] demonstrated that their crustal structure and shape can be described by a degree-2 harmonic that extends over about a quarter of the lunar surface. The process that generated this terrain would have likely once extended into the southern half of the farside and its characteristic degree-2 shape would have been obscured by the South Pole-Aitken impact. If so, the low topography in the southern central part of the basin, which is the lowest on the Moon, would be partially the result of the superposition of the SP-A excavation cavity over a preexisting degree-2 terrain that decreases in elevation and crustal thickness towards the south pole. We tested this hypothesis in several ways, including fitting degree-2 harmonics to the farside highlands and extrapolating them across the basin, “removing” the expected degree-2 signal from SP-A, and measuring the degree-2 character of the interior basin topography and crustal thickness. In all cases, there is evidence that the preexisting terrain was degree-2 in character, and that it controlled portions of the basin topography and crustal structure we see now. There are three implications of these results. The first is that the north-south asymmetry in the depth of SP-A [1] is not likely due to some asymmetry in the impact process that develops at very large scales. The second is that knowledge of the preexisting crustal

  15. 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.

  16. Classification and features of single-well flow units in a carbonate reservoir - Taking the NT oil field at the eastern edge of Pre-Caspian Basin as an example

    NASA Astrophysics Data System (ADS)

    Fan, Zifei; Wang, Shuqin; Liu, Lingli; Li, Jianxin; Zhao, Wenqi; Sun, Meng

    2017-01-01

    Identifying the carbonate reservoirs has always been a challenge to geological exploration, while reasonable classification of flow units is the bottleneck in this exploitation. While taking the NT oil field at the eastern edge of Pre-Caspian Basin as an example, this paper proposes the classification of flow units into five categories based on previous flow-unit classification theory and actual oilfield features by using the pore throat radius at the mercury injection saturation of 35% as the main judging criterion. In this paper, the features of various flow units have also been analyzed. The type-I flow units, mainly found in dolomite and algal reef limestone reservoirs, have the highest production capacity. Given the existence of corrosion and dolomitization, they are mainly fracture-cave composite reservoirs or fracture pore reservoirs. As far as the type-I flow units are concerned, the flow index is > 1.42 for KT-I stratum and > 1.55 for KT-II stratum. The production capacity and reservoir quality of type-II-IV flow units would decline in turn. The type-V flow units are argillaceous limestone, with a very low production capacity and a flow index being 0.01-0.05 for KT-I and 0.03-0.05 for KT-II.

  17. Edisto River Basin, South Carolina Feasibility Report for Water Resources Development.

    DTIC Science & Technology

    BASINS (GEOGRAPHIC), DRAINAGE, FLOOD CONTROL, HYDROELECTRICITY, OUTDOOR, PLANNING, POWER, QUALITY CONTROL, RECREATION, RIVERS , SOUTH CAROLINA, STREAMS, WATER QUALITY, WATER RESOURCES, WATER SUPPLIES, WIDTH

  18. Tsunamis in the central part of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Kulikov, E. A.; Kuzin, I. P.; Yakovenko, O. I.

    2014-07-01

    This paper describes the geotectonics of the Caspian Sea basin and the seismicity of its central part. The seismicity analysis enables us to identify the most probable zones of tsunami generation. We also present a brief review of the historical records of tsunamis in the Caspian Sea. In order to estimate the tsunami risk, we used the method of numerical hydrodynamic simulation while taking into account the real topography of the Caspian Sea. The computation of the wave field for the possible tsunamis occurring in the central part of the Caspian Sea allowed us to estimate the maximum expected heights of the waves along the coast of the CIS countries (Russia, Azerbaijan, Kazakhstan, and Turkmenistan). On the basis of the earthquake statistics in the region and the results of numerical experiments, we show that the extreme wave heights can reach 10 m at certain parts of the coast. Such extreme events correspond to extended (up to 200 km) seismic sources with M S ˜ 8 and a recurrence period of T ≈ 1600 years. The tsunami wave heights are expected to be as high as 3 m for sources of lesser extent (<50 km) with earthquake magnitudes of M S ˜ 7 and a recurrence period of 200 years.

  19. 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.

  20. Pulsed basin development on northern margin of South China Sea

    SciTech Connect

    Ru, K.; Pigott, J.D.

    1987-05-01

    Detailed analysis of the geothermal gradients, structural architecture, genetic stratigraphy, and subsidence rate history of the sedimentary basins on the northern margin of the South China Sea (NMSC) reveal three temporally distinct but regionally correlative tectonic extensional episodes. The timing of these pulsed episodes of basin development are: Episode One, Late Cretaceous to Paleocene; Episode Two, late Eocene to early Oligocene; and Episode Three, middle Miocene. Each initiating episode on the NMSC is characterized by an ephemeral (< 10 m.y.) increase in heat flow (> 3 HFU), formation of regionally en echelon grabens or half-grabens, ensuing transgression, and high subsidence rate (> 50 m/m.y.). Trends of basin boundaries and major fault trends evolved from predominantly northeast for Episode One, to northeast and east-west for Episode Two, and to northwest and east-west and for Episode Three. Tectonically, the northeast and east-west trends resulted primarily from rifting along northwest and north-south extensional directions, respectively. The orientation, sense of displacement and time of activation of the Red River fault, Vietnam fracture zone, and the northeast-east-west and northwest-east-west multiple sets of fractures may be explained as responses to episodic changes in the regional stress field utilizing the guidance of inherited zones of crustal weakness. The timing and extent of the hydrocarbon maturation, reservoir development, and stratigraphic-structural closure in the NMSC were directly affected by this pulsed tectonic activity. Therefore, exploration strategies based purely upon the NMSC being a passive rifted margin are both inappropriate and misleading.

  1. 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.

  2. 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.

  3. Heavy metals relationship with water and size-fractionated sediments in rivers using canonical correlation analysis (CCA) case study, rivers of south western Caspian Sea.

    PubMed

    Vosoogh, Ali; Saeedi, Mohsen; Lak, Raziyeh

    2016-11-01

    Some pollutants can qualitatively affect aquatic freshwater such as rivers, and heavy metals are one of the most important pollutants in aquatic fresh waters. Heavy metals can be found in the form of components dissolved in these waters or in compounds with suspended particles and surface sediments. It can be said that heavy metals are in equilibrium between water and sediment. In this study, the amount of heavy metals is determined in water and different sizes of sediment. To obtain the relationship between heavy metals in water and size-fractionated sediments, a canonical correlation analysis (CCA) was utilized in rivers of the southwestern Caspian Sea. In this research, a case study was carried out on 18 sampling stations in nine rivers. In the first step, the concentrations of heavy metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, and Cd) were determined in water and size-fractionated sediment samples. Water sampling sites were classified by hierarchical cluster analysis (HCA) utilizing squared Euclidean distance with Ward's method. In addition, for interpreting the obtained results and the relationships between the concentration of heavy metals in the tested river water and sample sediments, canonical correlation analysis (CCA) was utilized. The rivers were grouped into two classes (those having no pollution and those having low pollution) based on the HCA results obtained for river water samples. CCA results found numerous relationships between rivers in Iran's Guilan province and their size-fractionated sediments samples. The heavy metals of sediments with 0.038 to 0.125 mm size in diameter are slightly correlated with those of water samples.

  4. Caspian Sea Environmental Security Game: 16-17 November 1998

    DTIC Science & Technology

    1999-07-01

    markets. Russia to the north, Iran and Iraq to the south and southwest, Afghanistan to the southeast—all effectively block the way. 21 Which means...historic petroleum industry, post-Soviet burgeoning oil and gas development, and corresponding incidents of oil pollution. Some effects are seen in the...pollution potential of such activities. Increased production in the Caspian region could increase the above effects , no matter which pipeline route is

  5. Drainage areas in the Big Sioux River basin in eastern South Dakota

    USGS Publications Warehouse

    Amundson, Frank D.; Koch, Neil C.

    1985-01-01

    The Big Sioux River basin of eastern South Dakota contains an important surface water supply and a sizeable aquifer system of major importance to the economy of South Dakota. The aquifers are complex, consisting of many small aquifers that are hydrologically associated with several large aquifers and the Big Sioux River. The complexity and interrelation of the surface water/groundwater systems has already created management problems. As development continues and increases, the problems will increase in number and complexity. To aid in planning for future development, an accurate determination of drainage areas for all basins, sub-basins, and noncontributing areas in the Big Sioux River basin is needed. All named stream basins, and all unnamed basins > 10 sq mi within the Big Sioux River basin in South Dakota are shown and are listed by stream name. Stream drainage basins in South Dakota were delineated by visual interpretation of contour information shown on U.S. Geological Survey 77-1/2 minute topographic maps. One table lists the drainage areas of major drainage basins in the Big Sioux River basin that do not have a total drainage area value > 10 sq mi. Another shows the drainage area above stream gaging stations in the Big Sioux River basin. (Lantz-PTT)

  6. 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.

  7. 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

  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. 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

  10. 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.

  11. 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.; Stone, D.M.; Hite, D.M.

    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.

  12. Assessment of coalbed gas resources of the Central and South Sumatra Basin Provinces, Indonesia, 2016

    USGS Publications Warehouse

    Schenk, Christopher J.; Klett, Timothy R.; Tennyson, Marilyn E.; Mercier, Tracey J.; Brownfield, Michael E.; Pitman, Janet K.; Gaswirth, Stephanie B.; Finn, Thomas M.

    2016-12-09

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 20 trillion cubic feet of undiscovered, technically recoverable coalbed gas resource in the Central and South Sumatra Basin Provinces of Indonesia.

  13. Lithospheric velocity structure of the Anatolian plateau-Caucasus-Caspian region

    SciTech Connect

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

    2011-05-07

    The Anatolian plateau-Caucasus-Caspian region is an area of complex lithospheric 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 31 new, permanent broadband seismic stations along with results from a previous 29 temporary seismic stations and 3 existing global seismic stations in the region, a 3-D velocity model is developed using joint inversion of teleseismic receiver functions and surface waves. Both group and phase dispersion curves (Love and Rayleigh) were derived from regional and teleseismic events. Additional Rayleigh wave group dispersion curves were determined using ambient noise correlation. Receiver functions were calculated using P arrivals from 789 teleseismic (30°–90°) earthquakes. The stacked receiver functions and surface wave dispersion curves were jointly inverted to yield the absolute shear wave velocity to a depth of 100 km at each station. The depths of major discontinuities (sediment-basement, crust-mantle, and lithosphere-asthenosphere) were inferred from the velocity-depth profiles at the location of each station. Distinct spatial variations in crustal and upper mantle shear velocities were observed. The Kura basin showed slow (~2.7–2.9 km/s) upper crustal (0–11 km) velocities but elevated (~3.8–3.9 km/s) velocities in the lower crust. The Anatolian plateau varied from ~3.1–3.2 in the upper crust to ~3.5–3.7 in the lower crust, while velocities in the Arabian plate (south of the Bitlis suture) were slightly faster (upper crust between 3.3 and 3.4 km/s and lower crust between 3.8 and 3.9 km/s). The depth of the Moho, which was estimated from the shear velocity profiles, was 35 km in the Arabian plate and increased northward to 54 km at the southern edge of the Greater Caucasus. Moho depths in the Kura and at the edge of the Caspian showed more spatial variability but ranged between 35 and 45 km

  14. Lithospheric velocity structure of the Anatolian plateau-Caucasus-Caspian region

    DOE PAGES

    Gök, R.; Mellors, R. J.; Sandvol, E.; ...

    2011-05-07

    The Anatolian plateau-Caucasus-Caspian region is an area of complex lithospheric 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 31 new, permanent broadband seismic stations along with results from a previous 29 temporary seismic stations and 3 existing global seismic stations in the region, a 3-D velocity model is developed using joint inversion of teleseismic receiver functions and surface waves. Both group and phase dispersion curves (Love and Rayleigh) were derived from regional and teleseismic events. Additional Rayleigh wave group dispersion curves weremore » determined using ambient noise correlation. Receiver functions were calculated using P arrivals from 789 teleseismic (30°–90°) earthquakes. The stacked receiver functions and surface wave dispersion curves were jointly inverted to yield the absolute shear wave velocity to a depth of 100 km at each station. The depths of major discontinuities (sediment-basement, crust-mantle, and lithosphere-asthenosphere) were inferred from the velocity-depth profiles at the location of each station. Distinct spatial variations in crustal and upper mantle shear velocities were observed. The Kura basin showed slow (~2.7–2.9 km/s) upper crustal (0–11 km) velocities but elevated (~3.8–3.9 km/s) velocities in the lower crust. The Anatolian plateau varied from ~3.1–3.2 in the upper crust to ~3.5–3.7 in the lower crust, while velocities in the Arabian plate (south of the Bitlis suture) were slightly faster (upper crust between 3.3 and 3.4 km/s and lower crust between 3.8 and 3.9 km/s). The depth of the Moho, which was estimated from the shear velocity profiles, was 35 km in the Arabian plate and increased northward to 54 km at the southern edge of the Greater Caucasus. Moho depths in the Kura and at the edge of the Caspian showed more spatial variability but ranged between 35

  15. 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?

  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. 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.

  18. 78 FR 77644 - Black Hills National Forest, South Dakota; Thunder Basin National Grassland, Wyoming; Teckla...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... Forest Service Black Hills National Forest, South Dakota; Thunder Basin National Grassland, Wyoming... Dakota and portions of the Thunder Basin National Grasslands, private lands, BLM lands, and state lands... Grasslands in Douglas, WY at (307) 358- 4690. Individuals who use telecommunication devices for the deaf...

  19. 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

  20. Tectonic subsidence of the Zhu 1 Sub-basin in the Pearl River Mouth Basin, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, Xiaoyin; Yang, Shuchun; Zhu, Junzhang; Long, Zulie; Jiang, Guangzheng; Huang, Shaopeng; Hu, Shengbiao

    2017-01-01

    The Pearl River Mouth Basin, which is situated on the northern margin of the South China Sea, has attracted great attention not only because of its tectonic setting but also because of its abundant hydrocarbon resources. We have analyzed the Cenozoic tectonic subsidence history of 4 drilled wells and 43 artificial wells from the Zhu 1 Sub-basin of the Pearl River Mouth Basin by back-stripping, using newly interpreted seismic profiles. We also calculated the average tectonic sub-sidence rates of the four sags in the Zhu 1 Sub-basin. The rifting and post-rifting stages are separated by abrupt changes in the tectonic subsidence curves and average subsidence rates. In the eastern sags of the Zhu 1 Sub-basin, tectonic subsidence started to slow at ca. 30 Ma, compared with ca. 23.8 Ma in the western sags. This probably corresponds to the timing of break-up and suggests that rifting in the Pearl River Mouth Basin ended earlier in the eastern sags than in the western sags. Anomalously accelerated tectonic subsidence occurred at 17.5-16.4 Ma during the post-rifting stage, with average subsidence rates as high as 301.9 m/Myr. This distinguishes the Pearl River Mouth Basin from classical Atlantic passive continental marginal basins, which demonstrate exponentially decaying post-rift tectonic subsidence.

  1. 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...

  2. 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.

  3. 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.

  4. 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

  5. 137Cs inventory in semi-isolated basins of the western South Pacific

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Wang, Z.

    2007-12-01

    The main introduction routes of 137Cs into the Pacific Ocean are worldwide global fallout from atmospheric nuclear weapons testing and close-in fallout from U. S. tests conducted on the Bikini and Enewetak Atolls. The objectives of this study are to measure the 137Cs activities in water columns of the western South Pacific Ocean and to discuss the processes controlling the 137Cs inventory. The 137Cs activities were determined for seawater samples from the East Caroline, Coral Sea, New Hebrides, South Fiji and Tasman Sea Basins of the western South Pacific Ocean. The 137Cs activities in surface waters ranged from 1.7 Bq m- 3 in the Tasman Sea Basin to 2.3 Bq m-3 in the East Caroline Basin. The latitudinal 137Cs distributions in surface waters showed the opposite trend to the expected deposition density from global fallout. The distribution profiles of 137Cs activity at these six western South Pacific Ocean stations did not differ from each other significantly. The total 137Cs inventories in the western South Pacific Ocean ranged from 850 Bq m-2 in the Coral Sea Basin to 1270 Bq m-2 in the South Fiji Basin. Higher 137Cs inventories were observed at middle latitude stations in the subtropical gyre than at low latitude stations. The 137Cs inventories were 1.9 - 4.5 times higher than that of the expected deposition density of atmospheric global fallout at the same latitude. The possible sources of excess 137Cs inventories in the western South Pacific Ocean might be attributable to both the inter-hemisphere dispersion of the atmospheric nuclear weapons testing 137Cs from the northern stratosphere to the southern one and its subsequent deposition, and water- bearing transport of 137Cs from the North Pacific Ocean to the South Pacific.

  6. 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.

  7. 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.

  8. A cytogenetic study of the Caspian pony.

    PubMed

    Hatami-Monazah, H; Pandit, R V

    1979-11-01

    The group of Caspian ponies studied contained some animals with 65 chromosomes and others with 64 chromosomes. The morphology and G-banding pattern of the chromosomes resembled those of Equus caballus and E. przewalskii. The karyogram of animals with 65 chromosomes was identical to that of the cross between E. caballus and E. przewalskii. It is suggested that the Caspian pony is the product of natural hybridization between E. caballus and E. prezwalskii. Low reproductive effeciency of the Caspian pony is suggested as the cause of decline in the population of these animals.

  9. Abrupt and gradual extinction among Late Permian land vertebrates in the Karoo basin, South Africa.

    PubMed

    Ward, Peter D; Botha, Jennifer; Buick, Roger; De Kock, Michiel O; Erwin, Douglas H; Garrison, Geoffrey H; Kirschvink, Joseph L; Smith, Roger

    2005-02-04

    The Karoo basin of South Africa exposes a succession of Upper Permian to Lower Triassic terrestrial strata containing abundant terrestrial vertebrate fossils. Paleomagnetic/magnetostratigraphic and carbon-isotope data allow sections to be correlated across the basin. With this stratigraphy, the vertebrate fossil data show a gradual extinction in the Upper Permian punctuated by an enhanced extinction pulse at the Permian-Triassic boundary interval, particularly among the dicynodont therapsids, coinciding with negative carbon-isotope anomalies.

  10. Chemical quality of water and sedimentation in the Moreau River drainage basin, South Dakota

    USGS Publications Warehouse

    Colby, Bruce R.; Hembree, C.H.; Jochens, E.R.

    1953-01-01

    The Moreau River drainage basin is a narrow basin in northwestern South Dakota that covers about 5, 360 square miles of rolling, grassy plains, which are broken by buttes and by some small areas of badlands. It is underlain by shales, sandstones, siltstones, and limestones that are primarily of Cretaceous age. Precipitation averages about 16 inches per year. Average annual runoff is about 0. 7 inch but varies widely from year to year.

  11. 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

  12. Tectonic evolution of the north depression of the south Yellow Sea basin since late Cretaceous

    NASA Astrophysics Data System (ADS)

    Li, Nan; Li, Weiran; Long, Haiyan

    2016-12-01

    On the basis of subsidence history analysis and balanced cross-section analysis, the vertical uplift/subsidence history and horizontal extension/compression history of the north depression of the south Yellow Sea basin are quantitatively studied. The results show that the tectonic evolution of the north depression of the south Yellow Sea basin since late Cretaceous can be divided into a rifting phase (late Cretaceous to Paleogene) and a post-rifting phase (Neogene to Quaternary). The rifting phase can be further subdivided into an initial rifting stage (late Cretaceous), an intensive rifting stage (Paleocene), a rifting termination stage (Eocene), and an inversion-uplifting stage (Oligocene). Together, this division shows the characteristics of an episodic-evolved intracontinental rift-depression basin. The deformation of the north depression of the south Yellow Sea basin since late Cretaceous was mainly fault-related. The horizontal extension and tectonic subsidence were controlled by the activity of faults. The differential evolution of faults also caused variations in local uplift/subsidence movements and the regional heterogeneity in extension. The late Cretaceous initial rifting of the north depression of the south Yellow Sea basin is related to the Pacific-Eurasia convergence. From the Paleocene intensive rifting stage to present, the Pacific-Eurasia convergence and India-Eurasia convergence have played important roles in the evolution of this region.

  13. Divergence with gene flow between Ponto-Caspian refugia in an anadromous cyprinid Rutilus frisii revealed by multiple gene phylogeography.

    PubMed

    Kotlík, Petr; Marková, Silvia; Choleva, Lukás; Bogutskaya, Nina G; Ekmekçi, F Guler; Ivanova, Petya P

    2008-02-01

    The Black and Caspian Seas have experienced alternating periods of isolation and interconnection over many Milankovitch climate oscillations and most recently became separated when the meltwater overflow from the Caspian Sea ceased at the end of the last glaciation. Climate-induced habitat changes have indisputably had profound impacts on distribution and demography of aquatic species, yet uncertainties remain about the relative roles of isolation and dispersal in the response of species shared between the Black and Caspian Sea basins. We examined these issues using phylogeographical analysis of an anadromous cyprinid fish Rutilus frisii. Bayesian coalescence analyses of sequence variation at two nuclear and one mitochondrial genes suggest that the Black and Caspian Seas supported separate populations of R. frisii during the last glaciation. Parameter estimates from the fitted isolation-with-migration model showed that their separation was not complete, however, and that the two populations continued to exchange genes in both directions. These analyses also suggested that majority of migrations occurred during the Pleistocene, showing that the variation shared between the Black and Caspian Seas is the result of ancient dispersal along the temporary natural connections between the basins, rather than of incomplete lineage sorting or recent human-mediated dispersal. Gene flow between the refugial populations was therefore an important source of genetic variation, and we suggest that it facilitated the evolutionary response of the populations to changing climate.

  14. 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.

  15. 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

  16. A Re-Assessment of the Structure of the Southern Caspian Region From Teleseismic Receiver Functions

    NASA Astrophysics Data System (ADS)

    Raven, K. J.

    2002-12-01

    We have made teleseismic receiver function measurements at two new broadband seismograph stations in Turkmenistan in the vicinity of the south Caspian basin, and analyze an enlarged data set for three of the seismograph stations previously considered by Mangino and Priestley (1998). The new data help better constrain the crustal structure across the region and provide a better azimuthal distribution of receiver function measurements to discriminate between dipping, isotropic structure and crustal anisotropy beneath each of the sites. Along the trend of the Apshceron-Balkhan Sill-Kopet Dag Mountains the crust is 45+/-5 km thick. There is moderately strong tangential energy on all sites along the northern front of the Kopet Dag. Where sufficient azimuthal coverage of receiver functions is available, the tangential energy appears to arise from shallow dipping structure striking WNW, in agreement with the structure of the Kopet Dag Mountains. If anisotropy is present in the crust at these sites, its signal is weak with respect to that of the dipping interfaces. Receiver function analysis of data from one new site in the Turkmenian Lowlands confirms that the crust in this region is about 35 km thick.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Assessment of continuous oil and gas resources of the South Sumatra Basin Province, Indonesia, 2016

    USGS Publications Warehouse

    Schenk, Christopher J.; Tennyson, Marilyn E.; Klett, Timothy R.; Finn, Thomas M.; Mercier, Tracey J.; Gaswirth, Stephanie B.; Marra, Kristen R.; Le, Phuong A.; Hawkins, Sarah J.

    2016-12-09

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 689 million barrels of continuous shale oil and 3.9 trillion cubic feet of shale gas in the South Sumatra Basin Province in Indonesia.

  2. Understanding sedimentation in the Song Hong-Yinggehai Basin, South China Sea

    NASA Astrophysics Data System (ADS)

    Yan, Yi; Carter, Andrew; Palk, Carl; Brichau, StéPhanie; Hu, Xiaoqiong

    2011-06-01

    The Cenozoic Song Hong-Yinggehai Basin in the South China Sea contains a large volume of sediment that has been used in previous studies, together with regional geomorphology, to argue for the existence of a large palaeodrainage system that connected eastern Tibet with the South China Sea. To test this and to understand the significance of sediment volumes deposited in the Song Hong-Yinggehai Basin, this study compared erosion histories of source regions with sediment volumes deposited during the two main stages in basin evolution spanning active rifting and subsidence (30-15.5 Ma) and postrift sedimentation (15.5 Ma to present). The study of basin provenance by detrital zircon U-Pb dating revealed Hainan was an important and continuous source of sediment, and a bedrock thermochronological study quantified its overall contribution to basin sedimentation. Comparison between the accumulated mass of basin sediment and volumes of eroded bedrock, calculated from apatite thermochronometry across the modern Red River drainage in northern Vietnam as well as Hainan Island, accounted for the bulk of sediment deposited since 30 Ma. Consequently, if an expanded paleodrainage ever existed it must have predated the Oligocene.

  3. Biogeographic classification of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Fendereski, F.; Vogt, M.; Payne, M. R.; Lachkar, Z.; Gruber, N.; Salmanmahiny, A.; Hosseini, S. A.

    2014-11-01

    Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the hierarchical agglomerative clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow nearshore waters from those offshore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (one-way ANOVA, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence-absence patterns of 25 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.

  4. 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).

  5. 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.

  6. Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, Y.

    2009-12-01

    Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

  7. Exploration of drought evolution using numerical simulations over the Xijiang (West River) basin in South China

    NASA Astrophysics Data System (ADS)

    Niu, Jun; Chen, Ji; Sun, Liqun

    2015-07-01

    The knowledge of drought evolution characteristics may aid the decision making process in mitigating drought impacts. This study uses a macro-scale hydrological model, Variable Infiltration Capacity (VIC) model, to simulate terrestrial hydrological processes over the Xijiang (West River) basin in South China. Three drought indices, namely standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture anomaly index (SMAI), are employed to examine the spatio-temporal and evolution features of drought events. SPI, SRI and SMAI represent meteorological drought, hydrological drought and agricultural drought, respectively. The results reveal that the drought severity depicted by SPI and SRI is similar with increasing timescales; SRI is close to that of SPI in the wet season for the Liu River basin as the high-frequency precipitation is conserved more by runoff; the time lags appear between SPI and SRI due to the delay response of runoff to precipitation variability for the You River basin. The case study in 2010 spring drought further shows that the spatio-temporal evolutions are modulated by the basin-scale topography. There is more consistency between meteorological and hydrological droughts for the fan-like basin with a converged river network. For the west area of the Xijiang basin with the high elevation, the hydrological drought severity is less than meteorological drought during the developing stage. The recovery of hydrological and agricultural droughts is slower than that of meteorological drought for basins with a longer mainstream.

  8. 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.

  9. 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.

  10. Thermal basin modelling of the Arauco forearc basin, south central Chile — Heat flow and active margin tectonics

    NASA Astrophysics Data System (ADS)

    Kuhn, Philipp P.; Echtler, Helmut; Littke, Ralf; Alfaro, Guillermo

    2010-11-01

    The Arauco basin is part of the coastal forearc domain in South-Central Chile. During its evolution since the Late Cretaceous it was subject to multiple deposition cycles and the erosion of lower bathyal to beach and lagoon sediments. These different environments were established in alternating accretional and erosive subduction tectonic settings along the South Andean active margin. Whereas the general development is well understood, inconsistencies arise regarding the origin of the high thermal maturity of Eocene coals and the estimates of vertical movements of the whole area during the Cenozoic. Thermal modelling of this forearc basin provides new insights regarding its thermal evolution and evaluation of the magnitudes of subsidence and inversion. Results are based on the analysis of coal samples from surface outcrops, mines and drill cores of ten onshore wells from ENAP/Sipetrol. Newly derived vitrinite reflectance (VR r) measurements indicated a temperature in the range of 135-150 °C for the oldest sediment unit of the Arauco basin, which was reached in post Eocene times. Furthermore, 1D basin modelling techniques indicate scenarios that could explain the coalification values in the basin's sediments. The models were calibrated against VR r data from drill core samples supplied by ENAP/Sipetrol. A Miocene and an Oligocene subsidence/inversion scenario were considered, while neither could be securely discarded based on the modelling results. Furthermore, it can be shown that the current thermal maturity was not reached by an increased heat flow (HF) or a deep subsidence only. Consequently, a structural inversion accompanied by the erosion of ~ 3.0 ± 0.4 km depending on the locality in combination with a high HF of ~ 64 ± 4 mW/m 2 is the best explanation of the available data. The HF, which is high for a forearc setting, can be attributed to the increased temperature of the relatively young subducted Nazca Plate and an additional influence of ascending hot

  11. Tectonic and depositional model of the North Louisiana-South Arkansas basin

    SciTech Connect

    Sullivan, N.M. ); Lowrie, A. ); Krotzer, C.J.; Carter, J.; Lerche, I.; Petersen, K. )

    1993-09-01

    A tectonic and depositional model is presented for the North Louisiana-South Arkansas (NL-SA) basin. This area is defined as extending from the updip sedimentary outcrop limit of the Mississippi Embayment, to the Sabine uplift and its possible eastward extension to the Wiggens arch in the south, and lying between the Sabine and Monroe uplifts. Included in this designation is the North Louisiana Salt basin. Geohistory modeling of basin subsidence with time has been correlated to sediment deposition, as well as to regional climatic and oceanographic information. In each instance, quantification and/or ranges of the natural processes are provided. The objective is to develop a dynamic model framework accurate enough to underpin individual prospects with regional understanding. The tectonic chronology begins with (1) subduction in the lower Paleozoic, followed by (2) incipient and interrupted rifting that is possibly part of mantle plume rising in the upper Paleozoic. A second episode of magmatic intrusion associated with Upper Jurassic sea-floor spreading south of the Sabine uplift. Regional subsidence occurred from the edge of the Mississippi Embayment through the North Louisiana Salt basin, including the proto-Sabine uplift. Lower Cretaceous cessation of the central Gulf of Mexico spreading was accompanied by initiation of tectonic subsidence and the beginning of the South Louisiana Salt basin. A continued regional downdip existed from the edge of the Mississippi Embayment through the proto-Sabine uplift region. Middle Cretaceous subsidence rate in the NL-SA area, also impacted the evolution of sedimentary fill and associated structural evolution.

  12. 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.

  13. Simulating multi-decadal variability of Caspian Sea level changes using regional climate model outputs

    NASA Astrophysics Data System (ADS)

    Elguindi, N.; Giorgi, F.

    2006-02-01

    The Caspian Sea is the largest enclosed body of water on earth, covering approximately 4×105 km2 and sharing its coast with five countries (Iran, Azerbaijan, Kazakhstan, Russia and Turkmenistan). Because it has no outlet to the ocean the Caspian Sea level (CSL) has undergone rapid shifts in response to climatic forcings, and these have been devastating for the surrounding countries. In this paper we present the initial results of a modeling effort aimed at building a regional climate model for the Caspian Sea basin suitable to study the response of the CSL to interdecadal climate variability and anthropogenic climate change. Simulations are performed using the International Centre for Theoretical Physics (ICTP) regional climate model RegCM at a 50 km grid spacing for the period 1948 1990. During this period an abrupt shift occurred in the sea level after 1977, when the CSL rose about two meters until the early 1990s. Using a simple equation of hydrologic balance for the Caspian Sea basin to predict the CSL, we show that the model is able to reproduce the observed CSL changes at interannual to multidecadal scales. The correlation coefficient between the simulated and observed annual CSL changes is 0.91 and the model is able to reproduce the abrupt shift in CSL which occurred after 1977. Analysis of the climatologies before and after 1977 indicate that the CSL rise was mostly due to an increase in precipitation over the northern basin and a decrease in evaporation over the sea, primarily during the warm season. We plan to apply our model to the investigation of the response of the CSL to anthropogenic climate forcings.

  14. 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.

  15. Prospects for Dating the South Pole-Aitken Basin through Impact-Melt Rock Samples

    NASA Technical Reports Server (NTRS)

    Cohen, B. A.; Coker, R. F.; Petro, N. E.

    2016-01-01

    Much of the present debate about the ages of the nearside basins arises because of the difficulty in understanding the relationship of recovered samples to their parent basin. The Apollo breccias are from basin ejecta formations, which are ballistically-emplaced distal deposits that have mixed provenances. The Nectaris, Imbrium, and Serenitatis basins all have mare-basalt fill obscuring their original melt sheets, so geochemical ties are indirect. Though the geological processes acting to vertically and laterally mix materials into regolith are the same as at the Apollo sites, the SPA interior is a fundamentally different geologic setting than the Apollo sites. The South Pole-Aitken basin was likely filled by a large impact melt sheet, possibly differentiated into cumulate horizons. It is on this distinctive melt sheet that the regolith has formed, somewhat diluting but not erasing the prominent geochemical signature seen from orbital assets. By analogy to the Apollo 16 site, a zeroth-order expectation is that bulk samples taken from regolith within SPA will contain abundant samples gardened from the SPA melt sheet. However, questions persist as to whether the SPA melt sheet has been so extensively contaminated with foreign ejecta that a simple robotic scoop sample of such regolith would be unlikely to yield the age of the basin.

  16. 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.

  17. 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.

  18. 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.

  19. Recreational water quality in the Caspian Sea.

    PubMed

    Pond, Katherine R; Cronin, Aidan A; Pedley, Steve

    2005-06-01

    Health-based monitoring of the Caspian Sea in Turkmenistan and Iran suggests that bathers are intermittently subject to increased levels of faecal pollution which may lead to gastrointestinal illness. This is the first co-ordinated monitoring programme of recreational waters in the Caspian region and highlights the need to extend such a programme to all countries bordering the Caspian Sea. The novel approach of monitoring that combines risk assessment (water quality monitoring plus a sanitary survey) and risk management, as applied here, allows the identification of possible sources of pollution and the levels of microbiological risk that bathers are subject to. Hence, this allows suitable management interventions to be identified and implemented in the long-term.

  20. 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.

  1. 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.

  2. 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

    2000-03-03

    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.

  3. A new scheme for the opening of the South Atlantic Ocean and the dissection of an Aptian salt basin

    NASA Astrophysics Data System (ADS)

    Torsvik, Trond H.; Rousse, Sonia; Labails, Cinthia; Smethurst, Mark A.

    2009-06-01

    We present a revised model for the opening of the South Atlantic Ocean founded on a remapping of the continent-ocean boundaries and Aptian salt basins, the chronology of magmatic activity in and around the ocean basin and on the timing and character of associated intraplate deformation in Africa and South America. The new plate tectonic model is internally consistent and consistent with globally balanced plate motion solutions. The model includes realistic scenarios for intraplate deformation, pre-drift extension and seafloor spreading. Within the model, Aptian salt basins preserved in the South American (Brazilian) and African (Angola, Congo, Gabon) continental shelves are reunited in their original positions as parts of a single syn-rift basin in near subtropical latitudes (10°S-27°S). The basin was dissected at around 112 Ma (Aptian-Albian boundary) when the model suggests that seafloor spreading commenced north of the Walvis Ridge-Rio Grande Rise.

  4. The Canada Basin compared to the southwest South China Sea: Two marginal ocean basins with hyper-extended continent-ocean transitions

    NASA Astrophysics Data System (ADS)

    Li, Lu; Stephenson, Randell; Clift, Peter D.

    2016-11-01

    Both the Canada Basin (a sub-basin within the Amerasia Basin) and southwest (SW) South China Sea preserve oceanic spreading centres and adjacent passive continental margins characterized by broad COT zones with hyper-extended continental crust. We have investigated strain accommodation in the regions immediately adjacent to the oceanic spreading centres in these two basins using 2-D backstripping subsidence reconstructions, coupled with forward modelling constrained by estimates of upper crustal extensional faulting. Modelling is better constrained in the SW South China Sea but our results for the Canada Basin are analogous. Depth-dependent extension is required to explain the great depth of both basins because only modest upper crustal faulting is observed. A weak lower crust in the presence of high heat flow and, accordingly, a lower crust that extends far more the upper crust are suggested for both basins. Extension in the COT may have continued even after seafloor spreading has ceased. The analogous results for the two basins considered are discussed in terms of (1) constraining the timing and distribution of crustal thinning along the respective continental margins, (2) defining the processes leading to hyper-extension of continental crust in the respective tectonic settings and (3) illuminating the processes that control hyper-extension in these basins and more generally.

  5. Sources and summaries of water-quality information for the Rapid Creek basin, western South Dakota

    USGS Publications Warehouse

    Zogorski, John S.; Zogorski, E.M.; McKallip, T.E.

    1990-01-01

    This report provides a compilation of water quality information for the Rapid Creek basin in western South Dakota. Two types of information are included: First, past and current water quality monitoring data collected by the South Dakota Department of Water and Natural Resources, U.S. Forest Service, U.S. Geological Survey, and others are described. Second, a summary is included for all past water quality reports, publications, and theses that could be located during this study. A total of 62 documents were abstracted and included journal articles, abstracts, Federal agency reports and publications, university and State agency reports, local agency reports, and graduate theses. The report should be valuable to water resources managers, regulators, and others contemplating water quality research, monitoring, and regulatory programs in the Rapid Creek basin. (USGS)

  6. 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.

  7. On the origin age of the Southwest Basin in the South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Zhao-Shu; Yan, Pin; Liu, Hai-Ling

    1997-09-01

    This paper propounds that the origin and evolution of the Southwest Basin (SWB) in the South China Sea (SCS) are closely related with those of the SCS, reviews various viewpoints on its origin age with a large gap between the oldest age and the youngest age, offers some suggestions on the SWB’s origin age and gives some proposals to ascertain satisfactorily the origin and evolution, and multi-phasal and multiaxial spreading of the SCS and SWB.

  8. Ages for hominin occupation in Lushi Basin, middle of South Luo River, central China.

    PubMed

    Lu, Huayu; Sun, Xuefeng; Wang, Shejiang; Cosgrove, Richard; Zhang, Hongyan; Yi, Shuangwen; Ma, Xiaolin; Wei, Ming; Yang, Zhenyu

    2011-05-01

    A newly discovered Paleolithic site in loess deposits in the Lushi Basin, South Luo River, central China, is dated using pedostratigraphic analysis, optically stimulated luminescence (OSL) and magnetostratigraphic analysis. This region is regarded as an important place for hominin occupation and settlement during the early to middle Pleistocene. Results indicate that the archaeological site dates from 600ka to 620ka, reinforcing the view that Homo erectus had occupied a large area of eastern Asia by 620ka. The lithic assemblages of Lushi Basin is a flake and core technology, typical for this time period in north-central China. It may be compared with that at the Zhoukoudian locality 1 in north China and some sites in the Luonan Basin, and provides important data for understanding the behavior and stone tool technology of early Chinese hominins.

  9. 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.

  10. 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

  11. Radionuclides in plankton from the South Pacific Basin

    SciTech Connect

    Marsh, K.V.; Buddemeier, R.W.

    1984-03-23

    We have initiated an investigation of the utility of marine plankton as bioconcentrating samplers of low-level marine radioactivity in the southern hemisphere. A literature review has shown that both freshwater and marine plankton have trace element and radionuclide concentration factors (relative to water) of up to 10/sup 4/. We participated in Operations Deepfreeze 1981 and 1982, collecting a total of 48 plankton samples from the USCGC Glacier on its Antarctic cruises. Battelle Pacific Northwest Laboratories sampled air, water, rain, and fallout. We were able to measure concentrations in plankton of the naturally-occurring radionuclides /sup 7/Be, /sup 40/K, and the U and Th series, and we believe that we have detected low levels of /sup 144/Ce and /sup 95/Nb in seven samples ranging as far south as 68/sup 0/. Biological identification of the plankton suggests a possible correlation between radionuclide concentration and the protozoa content of the samples. 7 references, 5 figures.

  12. 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.

  13. 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.

  14. Long-term variability of extreme waves in the Caspian, Black, Azov and Baltic Seas

    NASA Astrophysics Data System (ADS)

    Arkhipkin, Victor; Dobroliubov, Sergey

    2013-04-01

    In order to study extreme storm waves in the Caspian, Black, Azov and Baltic Sea we used the spectral wave model SWAN. Significant wave height, swell and sea height, direction of propagation, their length and period were calculated with the NCEP/NCAR (1,9°x1,9°, 4-daily) reanalysis wind forcing from 1948 to 2010 in the Caspian, Black and Baltic Seas and with the NCEP/CFSR (0,3°x0,3°, 1 hour) for the period from 1979 to 2010 in the Azov Sea. The calculations were performed on supercomputers of Lomonosov Moscow State University (MSU). The spatial resolution of the numerical grid was of order 5 km for the Caspian, Baltic and Black Seas, 2 km for the Azov Sea. These model wave hindcasts were used to calculate interannual and seasonal variability of the storm frequency, location and duration. The Initial Distribution Method and Annual Maxima Series Methods were used to study probable waves of a century reoccurrence. The long-term variability of extreme waves revealed different trends in the investigated seas. The Caspian and Azov seas decreased the storm activity, while in the Baltic Sea the number of storm cases increased and the Black Sea showed no significant trend. The of more than 12 m were observed in two centers in the middle part of the Caspian Sea and in the center of the Baltic Sea. In the Black Sea the extreme waves of the same probability of more than 14 m were found in the region to the south of the Crimean peninsula. In the Azov Sea the highest waves of a century reoccurrence do not exceed 5 m. The work was done in Natural Risk Assessment Laboratory, MSU under contract G.34.31.0007.

  15. 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.

  16. New data on mantle seismicity of the Caspian region and their geological interpretation

    NASA Astrophysics Data System (ADS)

    Kovachev, S. A.; Kaz'min, V. G.; Kuzin, I. P.; Lobkovsky, L. I.

    2009-05-01

    The results of detailed seismological observations with bottom recording systems carried out in 2004 and 2006 near the Dagestan coast of the Middle Caspian are considered. The records of more than 550 micro- and weak earthquakes with ML = 0.1-4.7 (MLH = -0.7 to 4.3) were obtained during 165 days of recording; a fifth of these earthquakes occurred in the upper mantle at a depth of 50-200 km. Over the entire period of instrumental recording since the 1930s, only 10 mantle earthquakes with MLH = 3.5-6.3 have been recorded by on-land systems. The highest density of earthquake epicenters with source depths down to 50 km is established on the Middle Caspian coast between Derbent and Izberbash and in the adjacent water area. The mantle earthquakes with hypocenters at a depth of 60-80 km cluster beneath the western wall of the Derbent Basin, whereas deeper hypocenters are located beneath both the wall of this basin and the Middle Caspian coast. The sporadic mantle earthquakes recorded in 2004 (about 30 shocks), determined by a network of systems with a small aperture, depicted a zone plunging beneath the Greater Caucasus with indications of a peculiar “subduction” of the Scythian Plate beneath the Caucasus. Subsequent observations based on a more extensive network were carried out in 2006. They substantially changed the pattern of mantle earthquake hypocenters. According to this evidence, the sources of mantle earthquakes make up a dispersed cloud extended in the vertical direction beneath the Middle Caspian coast and water area, which may be regarded as a relic of tectonic activity of a bygone tectonic epoch. A comprehensive tectonic interpretation of the detected seismological phenomenon is given.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. Sedimentary successions and the onset of the Neoproterozoic Jiangnan sub-basin in the Nanhua rift, South China

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Zhou, Xiaolin; Deng, Qi; Fu, Xiugen; Duan, Taizhong; Guo, Xiumei

    2015-04-01

    Recent results of research from a regional geological survey have demonstrated that the Neoproterozoic Nanhuan strata in the Jiangnan sub-basin in the Nanhua rift in South China are built up of "wedge-shaped strata", which rest transgressively on the metamorphic basement. These strata are grouped, as indicated by our sedimentary facies analysis, into the following four depositional successions (with ten related sedimentary facies associations): (1) continental volcanic depositional succession; (2) continental siliciclastic depositional succession; (3) marine siliciclastic depositional succession; and (4) glacial depositional succession. Compared with the Hunan-Guangxi sub-basin and the Northern Zhejiang sub-basin, the sedimentary processes in the Jiangnan sub-basin are dominated by continental rather than marine facies. However, similar sedimentary successions with identical facies trends can be recognized in all these sub-basins. All the Neoproterozoic basin fills in South China are characterized by a deepening water trend leading from continental to fully marine facies, recording the evolution of a typical rift basin related to the break-up of Rodinia. The crystalline zircons from a rhyolite sample taken from the base part of the first succession in the Jiangnan sub-basin give a mean SHRIMP U-Pb age of 803 ± 9 Ma. The occurrence of the ca. 803 Ma volcanic rocks and the volcaniclastic rocks marks the onset of a new phase of depositional cycles in the Jiangnan sub-basin.

  5. 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)

  6. Evaluation of Drought Occurrence and Climate Change in the Pearl River Basin in South China

    NASA Astrophysics Data System (ADS)

    DU, Y.; Chen, J.; Wang, K.; Shi, H.

    2015-12-01

    This study uses the Variable Infiltration Capacity (VIC) Model to simulate the hydrological processes over the Pearl River basin in South China. The observed streamflow data in the Pearl River Basin for the period 1951-2000 are used to evaluate the model simulation results. Further, in this study, the 55 datasets of climate projection from 18 General Circulation Models (GCMs) for the IPCC AR4 (SRES A2/A1B/B1) and AR5 (RCP 2.6/4.5/6.0/8.5) are used to drive the VIC model at 0.5°× 0.5°spatial resolution and daily temporal resolution. Then, the monthly Standard Precipitation Index (SPI) and standardized runoff index (SRI) are generated to detect the drought occurrence. This study validates the GCMs projection through comparing the observed precipitation for the period of 2000-2013. Then, spatial variation of the frequency change of moderate drought, severe drought and extreme drought are analyzed for the 21st century. The study reveals that the frequencies of severe drought and extreme drought occurrences over the Pearl River Basin increase along with time. Specifically, for the scenario of AR5 RCP 8.5, the east and west parts of the Pearl River Basin most likely suffer from severe drought and extreme drought with an increased frequency throughout the 21st century.

  7. 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.

  8. Geological evolution of the West Luzon Basin (South China Sea, Philippines)

    NASA Astrophysics Data System (ADS)

    Arfai, J.; Franke, D.; Gaedicke, C.; Lutz, R.; Schnabel, M.; Ramos, E. G.

    2010-05-01

    Interpretation of new multichannel seismic data sheds insights into the geologic evolution of the West Luzon Basin (WLB), Philippines. The basin stretches for about 200 km in north-south direction and for up to 50 km in east-west direction. The West Luzon Basin is a sediment-filled trough that is located between the island of Luzon and the outer arc high of the eastward directed subduction of the South China Sea oceanic crust at the Manila Trench. However, at the southern end of the Manila Trench, where its trend changes from N-S to NW-SE and projects towards Mindoro, continental collision occurs (e.g. Lewis & Hayes, 1985). In 2008 approximately 1000 line-kilometres of regional multichannel seismic (MCS) data were obtained in the area of the WLB during a cruise with the German research vessel SONNE. In our MCS data six major unconformities in the WLB separate major stratigraphic units. We interpret high-amplitude, low-frequency reflection bands as acoustic basement that is dissected by normal faults. In the deep parts (4.5-5 s; TWT) of our E-W running seismic profiles we can trace a major fault system with a fault offset of 1-1.5 s (TWT). We suggest an initial development of the structure as a normal fault system, which later was inverted locally. A major change in the depositional regime occurs in the lower part of the sedimentary infill. A distinct bottom simulating reflector (BSR) is commonly observed. Grid calculations of the sediment thickness of the lower stratigraphic units give detailed values of deposition shifts and reveal variations in subsidence of the basin. Based on the depth of bottom simulating reflectors (BSR) heat flow values of 35-40 mW/m2 were calculated, which are typical for forearc basins. Two peculiarities of the WLB are not well in accordance with a forearc setting: The acoustic basement was affected by extensional deformation resulting in normal faulting with fault offsets up to 400 ms (TWT) but extension did not affect sedimentary layers

  9. Seismic Stratigraphy of the Central South China Sea Basin and Implications for Neotectonics

    NASA Astrophysics Data System (ADS)

    Li, C. F.; Ding, W.; Franke, D.; Yao, Y.; Pang, X.; Shi, H.; Li, J.; Cao, Y.

    2014-12-01

    International Ocean Discovery Program (IODP) Expedition 349 drilled five sites in the central South China Sea Basin. Three sites (U1431 in the East Subbasin, and U1433 and U1434 in the Southwest Subbasin) reached basalt interpreted to be igneous basement of the oceanic crust. Site U1435 on the northern continent-ocean boundary recovered pre-Oligocene sedimentary rocks deposited prior to the opening of the South China Sea. Furthermore, a full suite of geophysical logging was also carried out at Sites U1431 and U1433. These coring and logging data and physical property measurements are integrated with, and correlated to, regional reflection seismic data to map regional sequence stratigraphic boundaries and seismic facies of the central basin and the continent-ocean transition zone. With our carefully selected seismic profiles, stratigraphic correlation is possible even between the continent-ocean transition zone and the central basin, circumventing preexisting basement highs near the continent-ocean boundary that often prevent direct correlation. We interpret four sequence boundaries, which are Oligocene/Miocene, middle Miocene/late Miocene, Miocene/Pliocene, and Pliocene/Pleistocene boundaries. Seismic facies between sequence boundaries are often characteristic and distinctive, allowing relatively straightforward regional correlation. For example, massive Miocene carbonate deposits, if well consolidated, are readily distinguishable by strong seismic reflectivities, caused by their relatively higher density and velocity in contrast to those of interbedded turbidite clastic sediments. However, we found abrupt seismic facies changes both temporally and spatially. In particular, the fossil spreading ridge and the Zhongnan ridge between the East and Southwest Subbasins acted as major sedimentary barriers, across which seismic facies changes sharply and cannot be easily correlated. The well-constrained seismic sequence boundaries also allow us to estimate the timing of

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Selecting and Certifying a Landing Site for Moonrise in South Pole-Aitken Basin

    NASA Technical Reports Server (NTRS)

    Jolliff, B.; Watkins, R.; Petro, N.; Moriarty, D.; Lawrence, S.; Head, J.; Pieters, C.; Hagerty, J.; Fergason, R.; Hare, T.; Gaddis, L.; Hayne, P.

    2017-01-01

    MoonRise is a New Frontiers mission concept to land in the South Pole-Aitken (SPA) basin, collect samples, and return the samples to Earth for detailed mineral, chemical, petrologic, geochronologic, and physical properties analyses to address science questions relevant to the early evolution of the Solar System and the Moon. Science associated with this mission concept is described elsewhere; here we discuss selection of sites within SPA to address science objectives using recent scientific studies (orbital spectroscopy, gravity, topography), and the use of new data (LRO) to certify safe landing sites for a robotic sample return mission such as MoonRise.

  15. Construction Foundation Report, South Platte River Basin, Bear Creek Lake, Colorado. Volume 1. Text and Photos.

    DTIC Science & Technology

    1983-02-01

    Creek Project is on the east slope of the Colorado Front Range, just 2 miles east of the Dakota Hogback which forms the first prominent ridge of the...Rocky Mountains. Bear and Turkey Creeks flow eastward from their catchment areas in the mountains through gaps in the Dkota Hogback , across upturned...by the Dakota hogback , and on the south by a series of east-vest running knobs. * 3.11. Ground Water: Ground water in the Bear Creek Lake basin can be

  16. 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

  17. 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.

  18. 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

  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. A comparison of the South China Sea and Canada Basin: two small marginal ocean basins with hyper-extended margins and central zones of sea-floor spreading.

    NASA Astrophysics Data System (ADS)

    Li, L.

    2015-12-01

    Both the South China Sea and Canada Basin preserve oceanic spreading centres and adjacent passive continental margins characterized by broad COT zones with hyper-extended continental crust. We have investigated the nature of strain accommodation in the regions immediately adjacent to the oceanic spreading centres in these two basins using 2-D backstripping subsidence reconstructions, coupled with forward modelling constrained by estimates of upper crustal extensional faulting. Modelling is better constrained in the South China Sea but our results for the Beaufort Sea are analogous. Depth-dependent extension is required to explain the great depth of both basins because only modest upper crustal faulting is observed. A weak lower crust in the presence of high heat flow is suggested for both basins. Extension in the COT may continue even after sea-floor spreading has ceased. The analogous results for the two basins considered are discussed in terms of (1) constraining the timing and distribution of crustal thinning along the respective continental margins, (2) defining the processes leading to hyper-extension of continental crust in the respective tectonic settings and (3) illuminating the processes that control hyper-extension in these basins and more generally.

  1. Rift-related Devonian sedimentation and basin development in South China

    NASA Astrophysics Data System (ADS)

    Xun, Zhao; Allen, Mark B.; Whitham, Andrew G.; Price, Simon P.

    During Devonian times South China lay to the north of the Palaeo-Tethyan ocean, the boundary being a passive continental margin. A shallow sea covered the southern parts of the continent while northern areas, forming the Huanan Landmass, were emergent. At the beginning of the Devonian most of South China was above sea level. Subsequent transgression from the south gave rise to an irregular coastline with the development of many fault-controlled gulfs. Further transgression led to the development of an epicontinental sea with reefs forming along the margins of the submerged gulfs and black shales deposited within them. By Emsian time a widespread carbonate platform was established, while anoxic deposition continued in the troughs. The marine transgression peaked in the Frasnian Stage. During Famennian time widespread regression occurred and much of South China became once more emergent. Peneplanation of the Huanan Landmass led to the partial infilling of many of the older fault-bounded depressions. Throughout the Devonian the local distribution of sediments was strongly controlled by NE-SW trending transtensional faults that bounded NW-SE trending normal faults. These structures continued to influence sedimentation in the Late Palaeozoic, the Mesozoic and possibly the Tertiary in the offshore Beibu Gulf Basin.

  2. Seismicity in Azerbaijan and Adjacent Caspian Sea

    SciTech Connect

    Panahi, Behrouz M.

    2006-03-23

    So far no general view on the geodynamic evolution of the Black Sea to the Caspian Sea region is elaborated. This is associated with the geological and structural complexities of the region revealed by geophysical, geochemical, petrologic, structural, and other studies. A clash of opinions on geodynamic conditions of the Caucasus region, sometimes mutually exclusive, can be explained by a simplified interpretation of the seismic data. In this paper I analyze available data on earthquake occurrences in Azerbaijan and the adjacent Caspian Sea region. The results of the analysis of macroseismic and instrumental data, seismic regime, and earthquake reoccurrence indicate that a level of seismicity in the region is moderate, and seismic event are concentrated in the shallow part of the lithosphere. Seismicity is mostly intra-plate, and spatial distribution of earthquake epicenters does not correlate with the plate boundaries.

  3. 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.

  4. A fully-coupled atmosphere-ocean-wave model of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Bruneau, Nicolas; Toumi, Ralf

    2016-11-01

    Located in the mid-latitudes, the Caspian Sea is the largest enclosed basin in the world. A fully-coupled atmosphere-ocean-wave model of the Caspian Sea at high resolution (8 km) for a period of three years is presented. After validating each component of the modelling platform, the wave state of the Caspian Sea is studied. Results show very different wave regimes between the three different basins, a strong seasonality and an almost swell-free state. It is shown here that waves modify the horizontal eddy viscosity and vertical heat diffusion. However, due to a reasonably weak annual wave state, these effects are restricted to the upper-ocean layer (< 30 m) except during the most severe events (100 m). Three main experiments are conducted: 1) the ROMS ocean model forced by atmospheric reanalysis (CFSR), 2) ROMS coupled with the atmospheric model WRF and 3) the impact of wave-induced processes. The seasonality of the Caspian Sea is accurately captured in each experiment which highlights a rapid warming of the sea surface temperature (SST) in spring while the mixed layer depths (MLD) become very rapidly shallow (shifting from over 100 m to 15 m in two months). Contrarily, a gentle cooling of the SST accompanied with a deepening of the MLD is modelled during autumn and winter. The results also show a significant improvement of the model skill in the representation of the dynamics when ROMS is coupled to WRF. Finally, as ocean surface waves imply feedback at the interface atmosphere-ocean through the transfer of momentum, mass and heat, we investigate their potential effects on the Caspian Sea dynamics. Results are mixed and show a reasonably weak impact of wave-induced processes. While waves have a negligible effect during the winter as wave-induced mixing is confined to the MLD, the summer global SST are less accurately modelled due to the enhancement of mixing in shallow MLDs. However the SST bias, temperature at a subsurface location are improved.

  5. 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

  6. 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.

  7. Palynological and paleobotanical investigations of Paleogene sections in the Maoming basin, South China

    NASA Astrophysics Data System (ADS)

    Aleksandrova, G. N.; Kodrul, T. M.; Jin, J. H.

    2015-05-01

    The complex paleobotanical investigations carried out in the Maoming sedimentary basin (Guangdong Province, South China) yielded first data on the taxonomic composition and ecological properties of two large paleofloras from the Youganwo and Huangniuling formations. The palynomorph assemblages from these formations indicate their middle-late Eocene age (Lutetian-Bartonian and Priabonian for the former and latter, respectively). It is shown that sediments of the Youganwo Formation were deposited in an intermittently swamped lacustrine-fluvial plain, which gave way to a freshwater lake. Vegetation of this period was represented by wet subtropical forests with evergreen Fagaceae, Lauraceae, and Palmae. The Huangniuling flora reflects the biome of seasonal tropical forests developed in a broad fluvial plain and its margins. The Eocene floras of the Maoming Basin are marked by the appearance of several recent plant genera, which is also evident from finds of remains of their reproductive structures. The Eocene flora from low latitudes of South China exhibits a notable share of floral elements from middle and high latitudes of East Asia.

  8. 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

  9. 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

  10. Regolith in the South Pole-Aitken Basin is Mainly Indigenous Material

    NASA Technical Reports Server (NTRS)

    Haskin, L. A.; Gillis, J. J.; Jolliff, B. L.; Korotev, R. L.

    2003-01-01

    This abstract is concerned with the probability that a mission to a site within the South Pole-Aitken basin (SPA) would yield a meaningful sample of typical SPA floor material. The probability seems favorable, barring a highly atypical landing site, because the chemical composition of the SPA interior, as determined remotely from orbit, is different from that of the surrounding lunar surface. How representative would the sample be? To what extent have lateral transport or later events compromised the original chemical and mineralogical composition of the floor material? Where or in what kind of deposit should the mission land to provide the best example? We address these questions from the point of view of modeling of impact ejecta deposits. SPA is the largest lunar impact basin. Shallow for its diameter, it has a subdued gravity signature, a lower albedo, and a more Th- and Ferich interior than the surrounding highlands (the Feldspathic Highlands Terrane, FHT). Its floor may represent noritic or perhaps (but less abundant) gabbroic lower crust of the FHT, the upper crust stripped away by the basin-forming impact, possibly an oblique one.

  11. 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.

  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. )

    1996-01-01

    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.

  13. Monthly variations of the Caspian sea level and solar activity.

    NASA Astrophysics Data System (ADS)

    Romanchuk, P. R.; Pasechnik, M. N.

    The connection between 11-year cycle of solar activity and the Caspian sea level is investigated. Seasonal changes of the Caspian sea level and annual variations of the sea level with variations of solar activity are studied. The results of the verifications of the sea level forecasts obtained with application of the rules discovered by the authors are given.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  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. Structures of the northeasternmost South China Sea continental margin and ocean basin: geophysical constraints and tectonic implications

    NASA Astrophysics Data System (ADS)

    Li, Chun-Feng; Zhou, Zuyi; Li, Jiabiao; Hao, Hujun; Geng, Jianhua

    2007-03-01

    The northeastern part of the South China Sea is a special region in many aspects of its tectonics. Both recent drilling into the Mesozoic and new reflection seismic surveys in the area provide a huge amount of data, fostering new understanding of the continental margin basins and regional tectonic evolution. At least four half-grabens are developed within the Northern Depression of the Tainan Basin, and all are bounded on their southern edges by northwestward-dipping faults. One of the largest half-grabens is located immediately to the north of the Central Uplift and shows episodic uplift from the late Oligocene to late Miocene. Also during that period, the Central Uplift served in part as a material source to the Southern Depression of the Tainan Basin. The Southern Depression of the Tainan Basin is a trough structure with deep basement (up to 9 km below sealevel or 6 km beneath the sea bottom) and thick Cenozoic sedimentation (>6 km thick). Beneath the Southern Depression we identified a strong landward dipping reflector within the crustal layer that represents a significant crustal fault. This reflector coincides with a sharp boundary in crustal thicknesses and Moho depths. We show that the northeasternmost South China Sea basin, which may have undergone unique evolution since the late Mesozoic, is markedly different from the central South China Sea basin and the Huatung Basin, both geologically and geophysically. The Cenozoic evolution of the region was largely influenced by pre-existing weaknesses due to tectonic inheritance and transition. The South China Sea experienced multiple stages of Cenozoic extension.

  20. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. I.

    2010-03-01

    A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December-January; Eckman south-, south-westward drift in February-July embedded by western and eastern southward coastal currents and transition type in August-November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. The model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  1. Seasonal variability of the Caspian Sea three-dimensional circulation, sea level and air-sea interaction

    NASA Astrophysics Data System (ADS)

    Ibrayev, R. A.; Özsoy, E.; Schrum, C.; Sur, H. İ.

    2009-09-01

    A three-dimensional primitive equation model including sea ice thermodynamics and air-sea interaction is used to study seasonal circulation and water mass variability in the Caspian Sea under the influence of realistic mass, momentum and heat fluxes. River discharges, precipitation, radiation and wind stress are seasonally specified in the model, based on available data sets. The evaporation rate, sensible and latent heat fluxes at the sea surface are computed interactively through an atmospheric boundary layer sub-model, using the ECMWF-ERA15 re-analysis atmospheric data and model generated sea surface temperature. The model successfully simulates sea-level changes and baroclinic circulation/mixing features with forcing specified for a selected year. The results suggest that the seasonal cycle of wind stress is crucial in producing basin circulation. Seasonal cycle of sea surface currents presents three types: cyclonic gyres in December-January; Eckman south-, south-westward drift in February-July embedded by western and eastern southward coastal currents and transition type in August-November. Western and eastern northward sub-surface coastal currents being a result of coastal local dynamics at the same time play an important role in meridional redistribution of water masses. An important part of the work is the simulation of sea surface topography, yielding verifiable results in terms of sea level. Model successfully reproduces sea level variability for four coastal points, where the observed data are available. Analyses of heat and water budgets confirm climatologic estimates of heat and moisture fluxes at the sea surface. Experiments performed with variations in external forcing suggest a sensitive response of the circulation and the water budget to atmospheric and river forcing.

  2. The Hydrologic Regime of the La Plata Basin in South America

    NASA Astrophysics Data System (ADS)

    Berbery, E. H.; Barros, V. R.

    2002-12-01

    The main components of the hydrologic cycle of the La Plata basin in southeastern South America are investigated using a combination of observations, satellite products and National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) global reanalyses. La Plata basin is second only to the Amazon basin in South America, and plays a critical role in the economies of the region. It is a primary factor in energy production, water resources, transportation, agriculture and livestock. Of particular interest was to evaluate the annual cycle of the hydrologic cycle components. The La Plata annual-mean river discharge is about 21,000 m3 s-1, and the amplitude of the mean annual cycle of La Plata River discharge is small: it is slightly larger during late summer, but continues with large volumes even during winter. The reason is that different precipitation regimes over different locations contribute to the total river discharge. One regime is found toward the northern boundary, where precipitation peaks during summer in association with the southernmost extension of the monsoon system. A second one is found over the central part of the basin, where precipitation peaks at different times in the seasonal cycle. Further analysis of the main tributaries of La Plata (Paran , Uruguay and Paraguay) reveals that each has a well defined annual cycle, but with different phases that can be traced primarily to each basin's physiography and precipitation regime. The upper and middle portions of the Paran River are most influenced by the summer monsoon regime, thus the river has a maximum discharge in late summer. The annual cycle of precipitation over the Uruguay River basin has two maxima, one in late autumn and the second one in spring and, consistently, the river discharge is largest in winter and spring. The smooth annual cycle of the Paraguay River discharge, with a maximum in winter, is the result of the Pantanal, a large wetland that

  3. LRO Camera Imaging of Potential Landing Sites in the South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Jolliff, B. L.; Wiseman, S. M.; Gibson, K. E.; Lauber, C.; Robinson, M.; Gaddis, L. R.; Scholten, F.; Oberst, J.; LROC Science; Operations Team

    2010-12-01

    We show results of WAC (Wide Angle Camera) and NAC (Narrow Angle Camera) imaging of candidate landing sites within the South Pole-Aitken (SPA) basin of the Moon obtained by the Lunar Reconnaissance Orbiter during the first full year of operation. These images enable a greatly improved delineation of geologic units, determination of unit thicknesses and stratigraphy, and detailed surface characterization that has not been possible with previous data. WAC imaging encompasses the entire SPA basin, located within an area ranging from ~ 130-250 degrees east longitude and ~15 degrees south latitude to the South Pole, at different incidence angles, with the specific range of incidence dependent on latitude. The WAC images show morphology and surface detail at better than 100 m per pixel, with spatial coverage and quality unmatched by previous data sets. NAC images reveal details at the sub-meter pixel scale that enable new ways to evaluate the origins and stratigraphy of deposits. Key among new results is the capability to discern extents of ancient volcanic deposits that are covered by later crater ejecta (cryptomare) [see Petro et al., this conference] using new, complementary color data from Kaguya and Chandrayaan-1. Digital topographic models derived from WAC and NAC geometric stereo coverage show broad intercrater-plains areas where slopes are acceptably low for high-probability safe landing [see Archinal et al., this conference]. NAC images allow mapping and measurement of small, fresh craters that excavated boulders and thus provide information on surface roughness and depth to bedrock beneath regolith and plains deposits. We use these data to estimate deposit thickness in areas of interest for landing and potential sample collection to better understand the possible provenance of samples. Also, small regions marked by fresh impact craters and their associated boulder fields are readily identified by their bright ejecta patterns and marked as lander keep-out zones

  4. 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.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

    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.

  7. 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.

  8. 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

  9. Simulation of Atmospheric CO2 Concentrations in California’s South Coast Basin

    NASA Astrophysics Data System (ADS)

    Costigan, K. R.; Dubey, M. K.

    2009-12-01

    Verification of green house gas emission control treaties will require the coupling of measurements and models that can account for sources, sinks, and transport of these gasses. This paper presents an application of the Weather Research and Forecasting Chemistry model (WRF-Chem) to study CO2 transport in California’s South Coast Basin. The model is run for the week of 23-29 March 2008 to correspond with the atmospheric CO2 abundances measured with a ground-based Fourier transform spectrometer (FTS) and reported by Wunch et al. (2009). CO2 emissions used as input for the model are estimated from the Vulcan CO2 inventory (Gurney et al., 2009) and CO2 is treated as a passive tracer in the simulation. In particular, this paper addresses details of the simulation and analysis of the simulated meteorological conditions that may explain some of the observed day-to-day variations in CO2 concentrations.

  10. 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.

  11. 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.

  12. Small satellites with micro-propulsion for communications with the Lunar South Pole Aitkens Basin

    NASA Astrophysics Data System (ADS)

    Haque, Samudra E.; Straub, Jeremy; Whalen, David

    A lunar sample return mission to the Lunar South-Pole Aitkens Basin (LSPAB) has been highlighted as a high priority objective of the most recent (2011) Decadal Survey for Planetary Science, by the National Research Council. This class of mission, however, faces a dramatic communications limitation, due to the lack of a frequent, or continuous, line-of-sight communications path to Earth-based ground stations. Brunner and others have proposed a communications system utilizing Low Lunar Polar Orbits (LLPO) and Lunar Halo orbits for this purpose. Ely and others have outlined proposals for using several communication satellites to form a relay network using LLPO, taking into account the Lunar masscon's that would perturb such orbits. However, any relay network of communication satellites would still have to connect back to a suitable Earth-based ground station (Near Earth Network, or otherwise), or a tracking and data relaying satellite (e.g., TDRS).

  13. 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.

  14. 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.

  15. Contrasting Permo - Carboniferous Evolution of Resita and Sirinia - Presacina Basins (South Carpathians, Romania); an overview.

    NASA Astrophysics Data System (ADS)

    Tatu, M.; Seghedi, I.; Nutu, L. M.; Nicolae, I.

    2009-04-01

    Two important Permo-Carboniferous molasses basins Resita and Sirinia - Presacina occur in Romanian Banat (south-western part of Carpathian chain), unconformable overlie the Getic and Danubian domains with different pre-Variscan and Variscan geodynamic history. They show differences in their lithology reflecting various geotectonic settings and evolutions. In the Resita domain the Upper Carboniferous deposits (Westphalian - Stephanian in age, according to the previous paleobotanic and palynological data) are important in volume and they contain terrigeneous siliciclastic rocks represented by sandy - conglomerate and argillaceous - sandy rocks variable in thickness with siltstone, carbonaceous shale and coal beds interlayering. There are not volcanic rocks present in Upper Carboniferous of Resita domain. In contrast with Resita in the Sirinia - Presacina basins the Upper Carboniferous deposits are volumetrically more restrictive. These deposits transgresively overlie pre-Sudetian formations and consist of continental - lacustrine terrigeneous formations, rarely associated with limnic carbonatic rocks. In this association the alternating conglomerate, siliceous sandstone, siltstone and clay with lens - like coal inter-layers prevails. In two small areas Dragosela - Tulinecea - Camenita (in the western part) and Baia Noua - Cucuiova (in the eastern part) the terrigeneous deposits are associated with basaltic andesite and andesite rocks with alkaline affinity. In both of these basins the Lower Permian deposits (according to the paleobotanic data) unconformably overlie the Upper Carboniferous formations and/or pre-Sudetian basements. The Lower Permian deposits in the Resita basin occur in two superposed formations (Nastaseanu, 1987): (1) Walchia Beds dominated by black argillaceous shales, slightly bituminous with rare sandy-conglomerate interlayers and (2) Red Beds composed by sandy-conglomerate deposits with some argillaceous intercalations, all red in color, with

  16. Food Web Structure at South Su, Solwara 1 and Solwara 8 Hydrothermal Vent Sites (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Honig, D. L.; Hsing, P.; Jones, R.; Schultz, T.; Sobel, A.; Thaler, A.; van Dover, C. L.

    2008-12-01

    A robust understanding of food webs in chemoautotrophically based hydrothermal vent ecosystems requires quantifying the input of local bacterial chemoautoptrophic production vs. photosynthetically derived debris from surface waters. As an initial step towards this goal for vent communities in Papua New Guinea's Manus Basin, we use isotopic ratios of carbon, nitrogen and sulfur to describe trophic relations among 17 invertebrate genera collected in July 2008 at the Solwara 1, Solwara 8 and South Su hydrothermal vent beds. Prior stable isotope work by Erickson, Macko and Van Dover (unpublished) at Manus Basin vent sites suggests that we will see relatively depleted ä13C and ä15N values for the primary consumers Ifremeria, Alviniconcha and Olgasolaris compared to secondary consumers like the mobile, scavenging genera Munidopsis, Austinograea, Alvinocaris and Chorocaris, sessile suspension feeders of the genera Eochinolasmus and Vulcanolepas, and the predatory sponge Abyssocladia. We further hypothesize that mobile fauna will exhibit greater within-genus variance of ä13C, ä15N and ä34S values than sessile genera due to mobile organisms' ability to forage for photosynthetically derived detritus.

  17. 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.

  18. Weakening of the weekend ozone effect over California's South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Baidar, S.; Hardesty, R. M.; Kim, S.-W.; Langford, A. O.; Oetjen, H.; Senff, C. J.; Trainer, M.; Volkamer, R.

    2015-11-01

    We have observed lower nitrogen dioxide (NO2) and ozone (O3) during a hot weekend (summer 2010) from aircraft over the entire South Coast Air Basin (SoCAB). Surface concentrations of NO2, O3, and temperature from 1996 to 2014 corroborate that this lower O3 on weekends is increasingly likely in recent years. While higher surface O3 on the weekends (weekend ozone effect, WO3E) remains widespread, the spatial extent and the trend in the probability of WO3E occurrences (PWO3E) have decreased significantly compared to a decade ago. This decrease is mostly the result of lower O3 on hot weekends in recent years. PWO3E is lowest in the eastern SoCAB. The major decrease happened during the 2008 economic recession, after which PWO3E has stabilized at a 15-25% lower level throughout most of the basin. Future NOx reductions are likely to be increasingly effective at reducing O3 pollution initially under hot conditions in the coming decade.

  19. Magnetic signature of the lunar South Pole-Aitken basin: Character, origin, and age

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    A new magnetic map of the Moon, based on Lunar Prospector 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 Imbrian-age 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.

  20. 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.

  1. 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."

  2. Tectonic evolution of the South Fiji Basin: UNCLOS helps tackle regional tectonics

    NASA Astrophysics Data System (ADS)

    Herzer, R.; Roest, W.; Barker, D.; Mortimer, N.; Mauffret, A.; Lafoy, Y.

    2005-12-01

    Marine surveys to study the evolution of remnant arcs and backarc basins north of New Zealand have been complemented by UNCLOS surveys by three countries - France, New Zealand and Australia - with potential extended continental shelf claims in the region. The UNCLOS factor allowed 9 cruises to focus on the region in the past 9 years, collecting approximately 30,000 km of seismic reflection (5,000 deep crustal), 263,700 sq km of swath bathymetry, and 70 dredge samples. Feedback through sharing or publishing data and joint participation allowed efficient planning and deployment of academic and UNCLOS cruises. Two models for South Fiji (SFB) and Norfolk (NB) basin evolution arise from current studies: at the level of the Three Kings Ridge - NB - southern SFB both involve Pacific trench roll-back and southward propagating spreading, but one also uses two subduction systems and arc-continent collision. Linked spreading of the NB and SFB is invoked in both models, but the veracity and geodynamics of the link are not investigated. A growing body of petrological and radiometric evidence and the tectonics of the New Zealand continental margin point to tandem Early Miocene spreading of the SFB and NB despite published magnetic interpretations that would confine SFB spreading to the Oligocene. The Franco-NZ NOUCAPLAC-1 cruise, the last cruise relevant to UNCLOS in this region, included a scientific objective to investigate the SFB-NB link in the critical area bounded by the Loyalty Ridge (LR), the Cook Fracture Zone (CFZ), the Bounty spreading centre (BSC) and the Julia Lineament (JL) with swath mapping, magnetics and seismic reflection. Initial results show a complex bathymetry where a possible link between the BSC and the CFZ involves ridge propagation, overlapping spreading centres, rift blocks and overprinting volcanoes. The link to the JL was not adequately tested due to sparse coverage. Closer to the LR, a thick, faulted sedimentary basin was found.

  3. 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.

  4. 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

  5. Bio-geographic classification of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Fendereski, Forough; Vogt, Meike; Payne, Mark R.; Lachkar, Zouhair; Salman Mahini, AbdolRassoul; Hosseini, Seyyed Abbas; Gruber, Nicholas

    2013-04-01

    Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during the last few decades. However, due to the lack of a comprehensive archive of environmental observations for this area, the scientific understanding of this water body remains poor. In this study, an ecogeographical classification of the CS based on physical and biological information derived from space is developed. We applied self-organizing maps (SOMs) to satellite-derived physical data sets for sea surface temperature, wind speed, sea ice, photosynthetically active radiation and total suspended matter together with bathymetry and sea surface salinity data for clustering. As many of these variables are collinear, a subset of four independent variables was selected as input for the algorithm, including sea surface temperature, bathymetry, sea ice and the seasonal variation of sea surface salinity. Derived physically-based ecoregions were then compared with the annual mean climatology of remotely-sensed chlorophyll a, validated against a limited set of in situ chlorophyll data, as a means of cross validating the physically-based classifications. A good agreement between the physically-based and chlorophyll-based regimes was observed. The classification results showed a robust separation between the northern and the middle/southern basins. This differentiation can be seen in all of the individual physical variables as well as in the chlorophyll a distribution pattern and can be attributed to the great influence of the Volga River inflow. The second major pattern obtained was the separation of the shallow near-shore waters from the off-shore waters of the CS. The obtained classes also parallel the surrounding land biomes and climatic zones such as the continental climate, sub-tropical climate and the steppe zones. These results can assist policy makers and managers with a general outlook on the different major ecosystems of the surface pelagic

  6. The collision of South China with NW India to join Gondwanaland in the Cambrian: Provenance constraints from foreland basins

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    The paleogeographic position of the South China Block (SCB) during the early Paleozoic is important for understanding its affinity with Gondwanaland and addressing potential tectonic trigger for both the early Paleozoic Wuyi-Yunkai orogeny in South China and similar-aged orogenic events along Gondwanan margins. Detrital zircon U-Pb ages of Cambrian sandstones/metasandstones from the southwestern SCB reveal a predominant population at 1100¬-950 Ma, and zircon Hf-O isotopic results suggest three Precambrian episodes of juvenile crustal growth for the source provenance (ca. 3.0 Ga, ca. 2.5 Ga and ca. 1.0 Ga), with major crustal reworking at 0.58-0.50 Ga. This provenance record is distinctly different from the known tectonomagmatic record of the SCB, but matches well with the provenance record of Cambrian sandstones and Cambro-Ordovician tectonomagmatic events in the NW Indian Himalaya. Such a provenance linkage between the two continents appears to have started from the Ediacaran. We thus propose that the SCB likely collided with NW India during the assembling of Gondwanaland between the Ediacaran and the Cambrian. The collisional event propagated to eastern Himalaya during Cambro-Ordovician time as South China rotated relative to India to close the remnant ocean, causing the Cambro-Ordovician North India orogeny (also known as the Kurgiakh orogeny) along the Himalaya, as well as the intraplate Wuyi-Yunkai orogeny (>460-415 Ma) in South China. This collisional event also generated two peripheral foreland basins on both the Indian Gondwanaland and the South China sides. The foreland basin on the South China side (the Nanhua foreland basin), started as a failed Neoproterozoic continental rift, and appears to have experienced two stage of development. During the first stage between the Ediacaran and the Cambrian, the basin likely shared the same detrital sources as the foreland basin in NW India, with sediments predominantly derived from the East Africa orogen and the

  7. 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.

  8. 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

  9. High-Resolution Detrital Zircon Geo- and Thermochronometry of the Eocene Ainsa Basin, South Central Pyrenees, Spain

    NASA Astrophysics Data System (ADS)

    Thomson, K. D.; Stockli, D. F.; Clark, J. D.; Puigdefabregas, C.; Fildani, A.

    2015-12-01

    Foreland basin deposits in the South Central Pyrenees provide a natural laboratory for investigating the interplay between tectonic and sedimentary processes. Early Cenozoic foreland basin deposits preserve the record of hinterland erosion throughout Pyrenean collision. This study uses high-resolution detrital zircon (DZ) geo- and thermochronometry to investigate the progressive evolution of sediment provenance and paleodrainages through the stratigraphic record and across different depozones of the foreland basin. The Ainsa Basin in the South Central Pyrenees contains a secession of Eocene turbidite packages sampled in detail to examine the transition from fluvial to shelf-slope to deep marine environments. New data are congruent with previous DZ studies showing the turbidites are mixed from two main sources, Hercynian plutons from the Pyrenean axial zone and Cadomian/Caledonian plutonic and metamorphic rocks exposed in the Eastern Pyrenees. Although many of the turbidite packages yield similar DZ U-Pb signatures, detailed DZ U-Pb-He double dating resolves subtle differences between stratigraphic packages. These differences likely reflect varying degrees of mixing of multiple sources, or autogenic sorting during transport. Some units yield anomalous DZ U-Pb distributions, which potentially indicate an additional source region. Studying these anomalies will better our understanding of processes such as sediment bypass in marine canyons and fluvio-deltaic depozones as well as axial vs transverse paleodrainages. Also these anomalous signals can be traced throughout depozones in the basin and used to refine stratigraphic correlations between different parts of the basin. The data, Interpreted in the context of the structural and stratigraphic framework of the Pyrenean foreland basin, provide insights into processes during sediment delivery, paleodrainage networks, and the interplay between tectonic deformation and basin sedimentation.

  10. 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.

  11. 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

  12. 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.

  13. 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)

  14. Reconstruction of the Mesozoic subduction in the South China Sea and its implications on the opening of the South China Sea basins

    NASA Astrophysics Data System (ADS)

    Li, F.; Sun, Z.; Yang, H.

    2013-12-01

    Reconstruction of the Mesozoic subduction system in the South China Sea (SCS) can improve our understanding of the tectonic evolution in the region and holds important implications on the opening of the SCS basins. Here we report the locations of the Mesozoic volcanic arc and trench in the SCS based on satellite-derived magnetic and gravimetric data, as well as drilling data from the China National Offshore Oil Corporation. The magnetic data allows us to identify the volcanic arc, which is characterized as high positive magnetic anomaly (HPMA) due to serpentinization. Furthermore, the volcanic arc is verified by distributions of intermediate rocks that are determined from the drilling data. The gravimetric data is used to determine the locations of the Mesozoic trench. Our preliminary results show two distinct HPMA belts along the two sides of the SCS basins. The first one locates northwest to the ridge axis of the SCS basins and extends from Taiwan in the northeast to the Xisha Island in the southwest. The second one locates on the Nansha-Dangerous Ground, southeast to the opening axis of the southwest sub-basin of the SCS, and is nearly parallel to the orientation of the first one. In addition, the distribution of intermediate rocks within the two HPMA belts indicates that the two belts represent the present locations of the Mesozoic volcanic arc. Furthermore, we recognize the corresponding Mesozoic trench by peak gross horizontal gradient of bouguer gravity anomaly in the northeastern SCS. It is located northwest to the ridge axis of the SCS basins and southeast to the Mesozoic arc. Moreover, drilling sample MZ-1-1 from the area between the Mesozoic arc and trench has shown clear signatures of forearc basin sediments, providing additional support to our arc and trench locations. Based on the opening direction of the SCS basins, we interpret that the two HPMA belts belong to the same Mesozoic volcanic arc that is located on the Eurasia continental crust. The arc

  15. 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

  16. 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.

  17. Spatial analysis of water quality trends in the Han River basin, South Korea.

    PubMed

    Chang, Heejun

    2008-07-01

    Spatial patterns of water quality trends for 118 sites in the Han River basin of South Korea were examined for eight parameters-temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended sediment (SS), total phosphorus (TP), and total nitrogen (TN). A non-parametric seasonal Mann-Kendall's test determined the significance of trends for each parameter for each site between 1993 and 2002. There are no significant trends in temperature, but TN concentrations increased for the majority of the monitoring stations. DO, BOD, COD, pH, SS, and TP show increasing or decreasing trends with approximately half of the stations exhibiting no trends. Urban land cover is positively associated with increases in water pollution and included as an important explanatory variable for the variations in all water quality parameters except pH. Topography and soil factors further explain the spatial variations in pH, COD, BOD, and SS. BOD, COD, SS, and TP variations are consistently better explained by 100m buffer scale analysis, but DO are better explained by the whole basin scale analysis. Local water quality management or geology could further explain some variations of water quality. Non-point-source pollution exhibits strong positive spatial autocorrelation as measured by Moran's I, indicating that the incorporation of spatial dimensions into water quality assessment enhances our understanding of spatial patterns of water quality. The spatial regression models, compared to ordinary least square (OLS) models, always better explain the variations in water quality. This study suggests that spatial analysis of watershed data at different scales should be a vital part of identifying the fundamental spatio-temporal distribution of water quality.

  18. 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.

  19. 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

  20. Sedimentary Record of the Back-Arc Basins of South-Central Mexico: an Evolution from Extensional Basin to Carbonate Platform.

    NASA Astrophysics Data System (ADS)

    Sierra-Rojas, M. I.; Molina-Garza, R. S.; Lawton, T. F.

    2015-12-01

    The Lower Cretaceous depositional systems of southwestern Oaxaquia, in south-central Mexico, were controlled by tectonic processes related to the instauration of a continental arc and the accretion of the Guerrero arc to mainland Mexico. The Atzompa Formation refers to a succession of conglomerate, sandstone, siltstone, and limestone that crop out in southwestern Mexico with Early Cretaceous fauna and detrital zircon maximum depositional ages. The sedimentary record shows a transition from early fluvial/alluvial to shallow marine depositional environments. The first stage corresponds to juvenile fluvial/alluvial setting followed by a deep lacustrine depositional environment, suggesting the early stages of an extensional basin. The second stage is characterized by anabranched deposits of axial fluvial systems flowing to the NE-SE, showing deposition during a period of rapid subsidence. The third and final stage is made of tidal deposits followed, in turn, by abrupt marine flooding of the basin and development of a Barremian-Aptian carbonate ramp. We interpret the Tentzo basin as a response to crustal extension in a back-arc setting, with high rates of sedimentation in the early stages of the basin (3-4 mm/m.y), slower rates during the development of starved fluvial to tidal systems and carbonate ramps, and at the top of the Atzompa Formation an abrupt deepening of the basin due to flexural subsidence related to terrane docking and attendant thrusting to the west. These events were recorded in the back-arc region of a continental convergent margin (Zicapa arc) where syn-sedimentary magmatism is indicated by Early Cretaceous detrital and volcanic clasts from alluvial fan facies west of the basin. Finally, and as a response to the accretion of the Guerrero superterrane to Oaxaquia during the Aptian, a carbonate platform facing toward the Gulf of Mexico was established in central to eastern Oaxaquia.

  1. Hydrological impact of rainwater harvesting in the Modder river basin of central South Africa

    NASA Astrophysics Data System (ADS)

    Welderufael, W. A.; Woyessa, Y. E.; Edossa, D. C.

    2011-05-01

    Along the path of water flowing in a river basin are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves harnessing of water in the upstream catchment. Increased water usage at upstream level is an issue of concern for downstream water availability to sustain ecosystem services. The upstream Modder River basin, located in a semi arid region in the central South Africa, is experiencing intermittent meteorological droughts causing water shortages for agriculture, livestock and domestic purpose. To address this problem a technique was developed for small scale farmers with the objective of harnessing rainwater for crop production. However, the hydrological impact of a wider adoption of this technique by farmers has not been well quantified. In this regard, the SWAT hydrological model was used to simulate the hydrological impact of such practices. The scenarios studied were: (1) Baseline scenario, based on the actual land use of 2000, which is dominated by pasture (combination of natural and some improved grass lands) (PAST); (2) Partial conversion of Land use 2000 (PAST) to conventional agriculture (Agri-CON); and (3) Partial conversion of Land use 2000 (PAST) to in-field rainwater harvesting which was aimed at improving the precipitation use efficiency (Agri-IRWH). SWAT was calibrated using observed daily mean stream flow data of a sub-catchment (419 km2) in the study area. SWAT performed well in simulating the stream flow giving Nash and Sutcliffe (1970) efficiency index of 0.57 for the monthly stream flow calibration. The simulated water balance results showed that the highest peak mean monthly direct flow was obtained on Agri-CON land use (18 mm), followed by PAST (12 mm) and Agri-IRWH land use (9 mm). These were 19 %, 13 % and 11 % of the mean annual rainfall, respectively. The Agri-IRWH scenario reduced direct flow by 38 % compared to Agri-CON. On the other hand it was found that the

  2. 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

  3. 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

  4. 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

  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. Structural differences between the western and eastern Qiongdongnan Basin: evidence of Indochina block extrusion and South China Sea seafloor spreading

    NASA Astrophysics Data System (ADS)

    Zhang, Cuimei; Wang, Zhenfeng; Sun, Zhipeng; Sun, Zhen; Liu, Jianbao; Wang, Zhangwen

    2013-12-01

    Located at the intersection between a NW-trending slip system and NE-trending rift system in the northern South China Sea, the Qiongdongnan Basin provides key clues for us to understand the proposed extrusion of the Indochina Block along with Red River Fault Zone and extensional margins. In this paper we for the first time systematically reveal the striking structural differences between the western and eastern sector of the Qiongdongnan Basin. Influenced by the NW-trending slip faults, the western Qiongdongnan Basin developed E-W-trending faults, and was subsequently inverted at 30-21 Ma. The eastern sector was dominated by faults with NE orientation before 30 Ma, and thereafter with various orientations from NE, to EW and NW during the period 30-21 Ma; rifting display composite symmetric graben instead of the composite half graben or asymmetric graben in the west. The deep and thermal structures in turn are invoked to account for such deformation differences. The lithosphere of the eastern Qiongdongnan Basin is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed and the faults varied with the basal plate boundary. However, the Southern and Northern Uplift area and middle of the central depression is located on normal lithosphere and formed half grabens or simple grabens. The lithosphere in the western sector is transitional from very hot to normal. Eventually, the Paleogene tectonic development of the Qiongdongnan Basin may be summarized into three stages with dominating influences, the retreat of the West Pacific subduction zone (44-36 Ma), slow Indochina block extrusion together with slab-pull of the Proto-South China Sea (36-30 Ma), rapid Indochina block extrusion together with the South China Sea seafloor spreading (30-21 Ma).

  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. 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).

  10. 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.

  11. 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.

  12. 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

  13. 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.

  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. 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.

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

    USGS Publications Warehouse

    Sprague, Lori 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.

  17. Compositional heterogeneity of central peaks within the South Pole-Aitken Basin

    NASA Astrophysics Data System (ADS)

    Moriarty, D. P.; Pieters, C. M.; Isaacson, P. J.

    2013-11-01

    high-spectral and -spatial resolution Moon Mineralogy Mapper data, we investigate compositional variations across the central peak structures of four impact craters within the South Pole-Aitken Basin (SPA). Two distinct causes of spectral diversity are observed. Spectral variations across the central peaks of Bhabha, Finsen, and Lyman are dominated by soil development, including the effects of space weathering and mixing with local materials. For these craters, the central peak structure is homogeneous in composition, although small compositional differences between the craters are observed. This group of craters is located within the estimated transient cavity of SPA, and their central uplifts exhibit similar mafic abundances. Therefore, it is plausible that they have all uplifted material associated with melts of the lower crust or upper mantle produced during the SPA impact. Compositional differences observed between the peaks of these craters reflect heterogeneities in the SPA subsurface, although the origin of this heterogeneity is uncertain. In contrast to these craters, Leeuwenhoek exhibits compositional heterogeneity across its central peak structure. The peak is areally dominated by feldspathic materials, interspersed with several smaller exposures exhibiting a mafic spectral signature. Leeuwenhoek is the largest crater included in the study and is located in a region of complex stratigraphy involving both crustal (feldspathic) and SPA (mafic melt and ejecta) materials. The compositional diversity observed in Leeuwenhoek's central peak indicates that kilometer-scale heterogeneities persist to depths of more than 10 km in this region.

  18. 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.

  19. 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

  20. Ammonia sources in the California South Coast Air Basin and their impact on ammonium nitrate formation

    NASA Astrophysics Data System (ADS)

    Nowak, J. B.; Neuman, J. A.; Bahreini, R.; Middlebrook, A. M.; Holloway, J. S.; McKeen, S. A.; Parrish, D. D.; Ryerson, T. B.; Trainer, M.

    2012-04-01

    Observations from the NOAA WP-3D aircraft during CalNex in May and June 2010 are used to quantify ammonia (NH3) emissions from automobiles and dairy facilities in the California South Coast Air Basin (SoCAB) and assess their impact on particulate ammonium nitrate (NH4NO3) formation. These airborne measurements in the SoCAB are used to estimate automobile NH3 emissions, 62 ± 24 metric tons day-1, and dairy facility NH3 emissions, 33 ± 16 to 176 ± 88 metric tons day-1. Emission inventories agree with the observed automobile NH3:CO emission ratio, but substantially underpredict dairy facility NH3 emissions. Conditions observed downwind of the dairy facilities were always thermodynamically favorable for NH4NO3 formation due to high NH3 mixing ratios from the concentrated sources. Although automobile emissions generated lower NH3 mixing ratios, they also can thermodynamically favor NH4NO3 formation. As an aerosol control strategy, addressing the dairy NH3 source would have the larger impact on reducing SoCAB NH4NO3 formation.

  1. 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.

  2. 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.

  3. 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

  4. BASINS

    EPA Pesticide Factsheets

    Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) is a multipurpose environmental analysis system designed to help regional, state, and local agencies perform watershed- and water quality-based studies.

  5. Palynostratigraphy of the Chapada Group and its significance in the Devonian stratigraphy of the Paraná Basin, south Brazil

    NASA Astrophysics Data System (ADS)

    Grahn, Yngve; Mauller, Paula Mendlowicz; Pereira, Egberto; Loboziak, Stanislas

    2010-03-01

    The Alto Garças Sub-basin in the northern part of the Paraná Basin evolved differently from the Apucarana Sub-basin in the south. The marine environment was shallower in the Alto Garças Sub-basin, which contains proportionately more silty and arenaceous rocks. The formations and members defined in the Apucarana Sub-basin are therefore difficult to apply in the Alto Garças Sub-basin, where the Chapada Group (units 1-4) is more applicable. An integrated miospore and chitinozoan biozonation of the Chapada Group facilitates direct correlation between the Chapada Group's units and the classical formations of the Paraná Basin as defined in the Apucarana Sub-basin. The Furnas Formation and Chapada unit 1 constitute the same lithostratigraphic unit. Beds with rhyniophytes in the uppermost part of the Furnas Formation contain palynomorphs representative of the Si phylozone within the MN spore Zone (late Lochkovian), and the rhyniophyte beds occupy the same stratigraphic interval within Chapada unit 1 (the Lochkovian of the Paraná Basin lacks chitinozoans). The lower part of Chapada unit 2 contains spores of the PoW Su spore Zone and chitinozoans of the Ramochitina magnifica and Ancyrochitina pachycerata zones, together indicating a late Pragian-early Emsian age-span. The upper part of Chapada unit 2 corresponds to the GS (AP) and Per (AD pre-Lem) spore Zones, and chitinozoans of the Ancyrochitina parisi, the informal Ancyrochitina varispinosa and Alpenachitina eisenacki chitinozoan zones, thus suggestive of a late Emsian - earliest Givetian age-span. Unit 3 is a proximal and lateral facies equivalent of the upper part of unit 2. The lower part of unit 4 includes spores typical of the early Givetian Lli (AD Lem) spore Zone and chitinozoans of the Ramochitina stiphrospinata chitinozoan Zone; the uppermost (early late Frasnian) part contains spores of the lower BMu (IV) spore Zone and chitinozoans of the Lagenochitina avelinoi chitinozoan Zone. The sandstones of unit 3

  6. 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.

  7. Bio-geographic classification of the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Fendereski, F.; Vogt, M.; Payne, M. R.; Lachkar, Z.; Gruber, N.; Salmanmahiny, A.; Hosseini, S. A.

    2014-03-01

    Like other inland seas, the Caspian Sea (CS) has been influenced by climate change and anthropogenic disturbance during recent decades, yet the scientific understanding of this water body remains poor. In this study, an eco-geographical classification of the CS based on physical information derived from space and in-situ data is developed and tested against a set of biological observations. We used a two-step classification procedure, consisting of (i) a data reduction with self-organizing maps (SOMs) and (ii) a synthesis of the most relevant features into a reduced number of marine ecoregions using the Hierarchical Agglomerative Clustering (HAC) method. From an initial set of 12 potential physical variables, 6 independent variables were selected for the classification algorithm, i.e., sea surface temperature (SST), bathymetry, sea ice, seasonal variation of sea surface salinity (DSSS), total suspended matter (TSM) and its seasonal variation (DTSM). The classification results reveal a robust separation between the northern and the middle/southern basins as well as a separation of the shallow near-shore waters from those off-shore. The observed patterns in ecoregions can be attributed to differences in climate and geochemical factors such as distance from river, water depth and currents. A comparison of the annual and monthly mean Chl a concentrations between the different ecoregions shows significant differences (Kruskal-Wallis rank test, P < 0.05). In particular, we found differences in phytoplankton phenology, with differences in the date of bloom initiation, its duration and amplitude between ecoregions. A first qualitative evaluation of differences in community composition based on recorded presence-absence patterns of 27 different species of plankton, fish and benthic invertebrate also confirms the relevance of the ecoregions as proxies for habitats with common biological characteristics.

  8. The bly creek ecosystem study: Phosphorus transport within a euhaline salt marsh basin, North Inlet, South Carolina

    NASA Astrophysics Data System (ADS)

    Dame, Richard F.; Wolaver, Thomas G.; Williams, Thomas M.; Spurrier, John D.; Miller, Anne B.

    Phosphorus transport through the tidal creek linking the Bly Creek basin (North Inlet, South Carolina) and the surrounding water body was studied on 34 tidal cycles between 20 June 1983 and 19 June 1984. Annual estimates of phosphorus input to the basin via streamwater, groundwater, and via streamwater, groundwater, and rain totalled 19.6 kg P·y -1; PO 4 export from the basin was not significant. Within the basin, the salt marsh was shown to be an important sink for PO 4 (207 kg P·y -1) while the oyster reef community exported a statistically insignificant 7.7 kg P·y -1. The data suggest that the source of the PO 4 to the salt marsh is the water column or benthic sediments of the tidal creek. The salt marsh was a significant sink for particulate phosphorus, but those uptakes were less than the error on the insignificant fluxes into the basin via the water column. The oyster reef community was a statistically significant sink for total phosphorus (98 kg P·y -1).

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Seismic Stratigraphy around Continent-Ocean Boundary in the NW Sub-basin, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Chang, S. P.; Liu, C. S.; Hsu, H. H.; Chang, J. H.

    2015-12-01

    The northern continental margin of the South China Sea (SCS) is a passive margin, and have experienced rifting and seafloor spreading. From continental shelf to deep sea basin, the nature of the crust gradually changes from continental crust to oceanic crust. Many studies use a term "continent-ocean boundary (COB)", to describe the boundary between these two kinds of crust. This boundary is roughly located along the boundary between slope and deep sea basin, and roughly parallels to the 3000 m isobath in the northern SCS. This study analyzes many multiple channel seismic reflection profiles in the northern continental margin of the SCS, and has identified an angular unconformity between the slope and deep sea basin deposits at the COB in the NW sub-basin area. This unconformity extends from continental slope to NW sub-basin near the COB. Strata beneath the unconformity downlap to the basement. Furthermore, there is a strong reflector beneath the unconformity, and this strong reflector, called "Tom", represents a hiatus which was recognized by biostratigraphic analyses from Site 1148 of ODP Leg 184. The strata between the unconformity surface and reflector Tom pinch toward deep sea basin, and then the unconformity and reflector Tom merge into one reflector. Therefore, the unconformity might be an erosional surface. The strata covered the unconformity onlap the unconformity. Some portions of the COB have intrusions forming basement high, and the unconformity and strata are coherent with basement relief. The unconformity has been interpreted as a normal fault in some previous studies, but our study distinguishes it as an erosional surface. Besides, some previous studies consider the bottom of the sedimentary layers in the NW sub-basin as the onset of depositing deep sea environment, and suggested that it is related to the onset of seafloor spreading. However, we interpret the angular unconformity as the onset of deep sea environment, and it differs from the onset of

  15. 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

  16. 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

  17. A detrital record of continent-continent collision in the Early-Middle Jurassic foreland sequence in the northern Yangtze foreland basin, South China

    NASA Astrophysics Data System (ADS)

    Qian, Tao; Liu, Shaofeng; Wang, Zongxiu; Li, Wangpeng; Chen, Xinlu

    2016-12-01

    The Mesozoic northern Yangtze foreland basin system was formed by continental collision between the North China and South China plates along the Mianlue suture. Synorogenic stratigraphic sequences of Late Triassic to Early-Middle Jurassic age were developed in the northern Yangtze foreland basin. The upper Middle Jurassic Shaximiao Formation consists mainly of thick-bedded terrestrial successions that serve as the main body of the basin-filling sequences, suggesting intense tectonism in the peripheral orogeny of the foreland basin. Laser-ICP-MS U-Pb analysis of 254 detrital zircon grains from sandstone samples and several published Lower-Middle Jurassic samples, detrital compositions, petrofacies, and paleocurrent reconstructions in the northern Yangtze foreland basin indicate that discrete source areas included the Qinling-Dabieshan ranges and the Mianlue suture zone to the north, and the South China plate to the south. The stratigraphic succession and sediment provenance of the foreland basin imply that the early Mianlue oceanic basin, magmatic arc, and nonmarine molasse foreland basin during the period of deposition were modified or buried by the subsequent continent-continent collision between the North China-Qinling-Dabieshan plate and the Yangtze plate during the Jurassic, which followed the oblique amalgamation between these plates during the Middle-Late Triassic.

  18. Ammonia sources and ammonium nitrate formation in the California South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Nowak, J. B.; Neuman, J.; Bahreini, R.; Middlebrook, A. M.; Holloway, J. S.; Cai, C.; Kaduwela, A.; McKeen, S. A.; Parrish, D. D.; Ryerson, T. B.; Trainer, M.

    2011-12-01

    The South Coast Air Basin (SoCAB) of California is designated by the US Environmental Protection Agency (EPA) as being in non-attainment of the National Ambient Air Quality Standards (NAAQS) for both PM2.5 and PM10. Formation of fine aerosol nitrates (e.g., ammonium nitrate (NH4NO3)) from gas-phase ammonia (NH3) and nitric acid (HNO3) accounts for a significant fraction of the PM2.5 mass. Quantifying the sources of NH3 in the SoCAB is important for developing aerosol control strategies. Fast-time resolution observations of NH3, particulate ammonium (NH4+), and carbon monoxide (CO) made aboard the NOAA WP-3D aircraft during the CalNex 2010 campaign are used to quantify and compare the major NH3 sources to the SoCAB atmosphere: automobiles and dairy farms. From the automobile NH3:CO emission ratio inferred from the WP-3D observations and CO inventory data the NH3 automobile emissions in the SoCAB are estimated at 38 ± 15 metric tons day-1. Atmospheric mass fluxes are calculated for observed NH3 plumes from dairy farms to estimate the NH3 dairy farm emissions at 27 ± 14 to 120 ± 60 metric tons day-1. Comparison with two emission inventories show good agreement for the automobile NH3:CO emission ratio, however, both inventories under predict NH3 emissions from the dairy farms. The observations suggest that automobiles and dairy farms contributed similar amounts of NH3 to the SoCAB in May 2010. However, observed particle mass was greater downwind from dairy farms, where high NH3 mixing ratios from more concentrated sources shift the NH4NO3 equilibrium toward favorable thermodynamic conditions for the condensation of NH4NO3 onto particles.

  19. Mediterranean shelf-edge muddy contourites: examples from the Gela and South Adriatic basins

    NASA Astrophysics Data System (ADS)

    Verdicchio, Giuseppe; Trincardi, Fabio

    2008-06-01

    We present new evidence of shallow-water muddy contourite drifts at two distinct locations in the central Mediterranean characterized by a relatively deep shelf edge (between 170 and 300 m below sea level): the south-eastern Adriatic margin and the north-western Sicily Channel. The growth of these shelf-edge contourite drifts is ascribed to the long-term impact of the Mediterranean themohaline circulation. The Levantine Intermediate Water flows continuously, with annual or inter-annual variations, and affects the shelf edge and the upper slope in both study areas. In addition, the SW Adriatic margin is impinged by the seasonally modulated off-shelf cascading of North Adriatic Dense Water. This water mass has formed ever since the large Adriatic continental shelf was drowned by the post-glacial sea-level rise. It energetically sweeps the entire slope from the shelf edge to the deep basin. These bottom currents flow parallel or oblique to the depth contours, and are laterally constricted along markedly erosional moats aligned parallel to the shelf edge where they increase in flow velocity. The internal geometry and growth patterns of the shelf-edge contourites reflect changes in oceanographic setting affecting the whole Mediterranean Sea. In particular, seismic correlation with published sediment cores documents that these deposits are actively growing and migrating during the present interglacial, implying an enhancement in bottom-water formation during intervals of relative sea-level rise and highstand. Regardless of the specific mechanisms of formation, sediment drifts in both study areas have been affected by widespread thin-skinned mass-wasting events during post-glacial times. Repeated mass-transport processes have affected in particular the downslope flank of the shelf-edge contourite drifts, indicating that these muddy deposits are prone to failure during, or soon after, their deposition.

  20. Inhalation intake of ambient air pollution in California's South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Marshall, Julian D.; Granvold, Patrick W.; Hoats, Abigail S.; McKone, Thomas E.; Deakin, Elizabeth; W Nazaroff, William

    Reliable estimates of inhalation intake of air pollution and its distribution among a specified population are important for environmental epidemiology, health risk assessment, urban planning, and environmental policy. We computed distributional characteristics of the inhalation intake of five pollutants for a group of ˜25,000 people (˜29,000 person-days) living in California's South Coast Air Basin. Our approach incorporates four main inputs: temporally resolved information about people's location (latitude and longitude), microenvironment, and activity level; temporally and spatially explicit model determinations of ambient concentrations; stochastically determined microenvironmental adjustment factors relating the exposure concentration to the ambient concentration; and, age-, gender-, and activity-specific breathing rates. Our study is restricted to pollutants of outdoor origin, i.e. it does not incorporate intake in a microenvironment from direct emissions into that microenvironment. Median estimated inhalation intake rates (μg d -1) are 53 for benzene, 5.1 for 1,3-butadiene, 8.7×10 -4 for hexavalent chromium in fine particulate matter (Cr-PM 2.5), 30 for diesel fine particulate matter (DPM 2.5), and 68 for ozone. For the four primary pollutants studied, estimated median intake rates are higher for non-whites and for individuals in low-income households than for the population as a whole. For ozone, a secondary pollutant, the reverse is true. Accounting for microenvironmental adjustment factors, population mobility and temporal correlations between pollutant concentrations and breathing rates affects the estimated inhalation intake by 40% on average. The approach presented here could be extended to quantify the impact on intakes and intake distributions of proposed changes in emissions, air quality, and urban infrastructure.

  1. 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.

  2. 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.

  3. 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.

  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.

  5. Reductions in human benzene exposure in the California South Coast Air Basin

    NASA Astrophysics Data System (ADS)

    Fruin, Scott A.; Denis, Michael J. St; Winer, Arthur M.; Colome, Steven D.; Lurmann, Frederick W.

    Benzene typically contributes a significant fraction of the human cancer risk associated with exposure to urban air pollutants. In recent years, concentrations of benzene in ambient air have declined in many urban areas due to the use of reformulated gasolines, lower vehicle emissions, and other control measures. In the California South Coast Air Basin (SoCAB) ambient benzene concentrations have been reduced by more than 70% since 1989. To estimate the resulting effect on human exposures, the Regional Human Exposure (REHEX) model was used to calculate benzene exposures in the SoCAB for the years 1989 and 1997. Benzene concentration distributions in 14 microenvironments (e.g. outdoor, home, vehicle, work) were combined with California time-activity patterns and census data to calculate exposure distributions for 11 demographic groups in the SoCAB. For 1997, the calculated average benzene exposure for nonsmoking adults in the SoCAB was 2 ppb, compared to 6 ppb for 1989. For nonsmokers, about half of the 1997 exposure was due to ambient air concentrations (including their contributions to other microenvironments), but only 4% for smokers. Passive tobacco smoke contributed about one-fourth of all exposure for adult nonsmokers. In-transit microenvironments and attached garages contributed approximately 15 and 10%, respectively. From 1989 to 1997, decreases in passive smoke exposure accounted for about one-sixth of the decrease in exposure for nonsmoking adults, with the remainder due to decreases in ambient concentrations. The reductions in exposure during this time period indicate the effectiveness of reformulated fuels, more stringent emission standards, and smoking restrictions in significantly reducing exposure to benzene.

  6. 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

  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. Simulation Oil Background Pollution of the Caspian Sea Based on Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergey

    At present time scales of oil pollution of the seas constantly increase. Such critical juncture of things is characteristic for the Caspian Sea at the expense of increase of oil extraction and transportation. However pure oil (crude oil) is rare. Most spills are formed as a result of an oil tanker cracking or an oil platform problem. Oil products or surfactants (synthetic surfactants) are the most common reasons for the creation of oil slicks of man-made origin. These products get into the sea in most different ways: with river runoff, with ship wastes, with sewage water. A separate issue is the oil seeping from natural mud springs on the sea bottom - it forms thin oil films that, generally speaking, are not man-made pollutions. Nonetheless, they contribute to the total level of pollution, especially on the south-western part of the Caspian Sea. Remote radar sensing from space (SAR imagery) allow conducting diagnostics and observation of movement and transformation of oil pollution on sea surface. However they do not give an estimation of oil spills influence on values of oil content in water and the forecast of their transfer. In the report the model of distribution, destruction, evaporation and sedimentation of oil hydrocarbons is suggested for time interval 1993-2007. Oil hydrocarbons pollutions values of river runoff (more than 90This study was supported by the grant of the Russian Foundation for Basic Research (06-05-64871), and by the INTAS Project "ALTImetry for Coastal REgions" (ALTICORE).

  9. 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

  10. Investigation of spatio-temporal water level and mass oscillations by using satellite gravimetry, altimetry and thermal data in Caspian Sea

    NASA Astrophysics Data System (ADS)

    Moradi, A.; de Viron, O.; Metivier, L.

    2012-12-01

    As Caspian Sea does not communicate with the world oceans, its dynamics are very different from the global water. Although -as for the world ocean- its level presents regular annual oscillations, estimations from last century and new more precise measurements shows large interannual fluctuations. Changes in the Caspian Sea water volume are investigated using space altimetry, whereas the GRACE satellite gravimetry mission allows monitoring the change of the surface mass distribution. Under the hypothesis that the change in water mass is the only cause of gravity change, it is possible to convert the mass distribution change into volume change, using a steric equation for the sea water. Combinations of multi-mission gridded altimetry data from AVISO with mono mission time series were used in order to analyze the local fluctuations of the lake, revealing a significant tilt between north and south. Large differences in the surface mass distribution rate of change in the basin and in the lake are evidenced in the GRACE data, as well as small differences in phase, which are due to delayed snow melting. Ignoring the short-term changes in water level due to winds, the main reason to cause periodic spatial water level disuniformity is spatial disuniformity in water density. Steric effect was calculated by interfering 2 factors of temperature and salinity. Steric anomaly maps show that it is able to change water level up to 17 cm. As the northern part of the lake has the least salinity in summers the largest effect would be expected to occur in the northern part, but the opposite is observed, probably due to the fact that this part is the shallowest. For the steric anomaly the lake presents spatially variations of 3 cm in winter but 7 cm in the summers. Generally, the largest steric induced fluctuations are observed in the middle of the lake, mostly in the north and east parts of the lake center. We used altimetry and space gravity data jointly, in order to build an improved

  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. 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.

  14. 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.

    2017-01-01

    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.

  15. Propagated rifting in the Southwest Sub-basin, South China Sea: Insights from 3D analogue modeling

    NASA Astrophysics Data System (ADS)

    Ding, Weiwei; Li, Jiabiao

    2015-04-01

    Most of earth scientists agree that the South China Sea is a rifted marginal sea in the western Pacific. How and when the South China Sea rifted has long been a puzzling question and still debated, especially in the Southwest Sub-basin (SWSB). Analog modeling remains one of the useful tools for testing rift model and process. Here we present and discuss a series of analog modeling experiments designed to investigate the rifting process of the SWSB. Convincing geophysical data were compiled to provide truthful constraints to test the experimental results and interpretations. The results show that rigid tectonic blocks existed in the continental margin, such as the Zhongsha Islands and the Reed Bank, and played an important role in shaping up the continent-ocean boundary (COB) and the coupling between the crust and mantle. Our data suggest that the initial thermal condition and rheologial stratification of the lithosphere under the South China Sea controlled the rifting process of the SWSB. The first-stage seafloor spreading has weakened the lithosphere surrounding the East Sub-basin, and the extension was centered on the deep troughs between the rigid blocks. Rifting bagan in these deep troughs in the east part of the SWSB, and the break-up occurred in localized areas between the rigid blocks. The V-shaped configuration of the SWSB also argues for a propagated rifting model.

  16. 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.

  17. 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.

  18. Comparison of the Geologic Setting of the South Pole-Aitken Basin Interior with Apollo 16: Implications for Regolith Components

    NASA Technical Reports Server (NTRS)

    Petro, N. E.; Pieters, C. M.

    2004-01-01

    The interior of the South Pole-Aitken Basin (SPA) contains ancient cratered terrain that is possibly remnant of the original interior of the basin. This terrain has been modified by the addition of and mixing with foreign material introduced by later basins and craters of all sizes (lateral and vertical mixing). Since much of our thinking about ancient regolith is based on detailed analysis of samples from one nearside ancient heavily cratered highland site, Apollo 16 (Ap16), it is instructive to compare the interior of SPA with the Ap16 landing site. For this comparison we use a central location within SPA (SPA-1 at 60 deg. S, 160 deg. W). Two models have recently been presented that allow estimation of the amount of original SPA interior material likely to remain in the regolith of SPA. Although the details of each model are different, results consistently range from 50-82% original material in the regolith. The models also allow the contribution from individual basins to be predicted.

  19. 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.

  20. 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.

  1. 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

  2. The extreme 2014 flood in south-western Amazon basin: the role of tropical-subtropical South Atlantic SST gradient

    NASA Astrophysics Data System (ADS)

    Carlo Espinoza, Jhan; Marengo, José Antonio; Ronchail, Josyane; Molina Carpio, Jorge; Noriega Flores, Luís; Loup Guyot, Jean

    2014-12-01

    Unprecedented wet conditions are reported in the 2014 summer (December-March) in South-western Amazon, with rainfall about 100% above normal. Discharge in the Madeira River (the main southern Amazon tributary) has been 74% higher than normal (58 000 m3 s-1) at Porto Velho and 380% (25 000 m3 s-1) at Rurrenabaque, at the exit of the Andes in summer, while levels of the Rio Negro at Manaus were 29.47 m in June 2014, corresponding to the fifth highest record during the 113 years record of the Rio Negro. While previous floods in Amazonia have been related to La Niña and/or warmer than normal tropical South Atlantic, the 2014 rainfall and flood anomalies are associated with warm condition in the western Pacific-Indian Ocean and with an exceptionally warm Subtropical South Atlantic. Our results suggest that the tropical and subtropical South Atlantic SST gradient is a main driver for moisture transport from the Atlantic toward south-western Amazon, and this became exceptionally intense during summer of 2014.

  3. Dust deposits in Souss?Massa basin, South-West of Morocco: granulometrical, mineralogical and geochemical characterisation

    NASA Astrophysics Data System (ADS)

    Khiri, F.; Ezaidi, A.; Kabbachi, K.

    2004-08-01

    Samples of dust deposits were periodically collected from July 1, 1997 to January 30, 1999, at Souss-Massa basin, in the South of Morocco. Granulometrical, geochemical and mineralogical characterisations show that quartz, calcite and feldspars dominate the mineral contents of the dust deposit with a minor clay fraction. It indicates the mineralogical composition of dust collected in peri-Saharan regions. The material collected in the summer period is dominated by local dust against a mixture of local and proximal dusts in the winter period.

  4. 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

  5. Remote Sensing of Subsurface Fractures in the Otway Basin, South Australia

    NASA Astrophysics Data System (ADS)

    Bailey, Adam; King, Rosalind; Holford, Simon; Hand, Martin

    2013-04-01

    A detailed understanding of naturally occurring fracture networks within the subsurface is becoming increasingly important to the energy sector, as the focus of exploration has expanded to include unconventional reservoirs such as coal seam gas, shale gas, tight gas, and engineered geothermal systems. Successful production from such reservoirs, where primary porosity and permeability is often negligible, is heavily reliant on structural permeability provided by naturally occurring and induced fracture networks, permeability, which is often not provided for through primary porosity and permeability. In this study the Penola Trough, located within the onshore Otway Basin in South Australia, is presented as a case study for remotely detecting and defining subsurface fracture networks that may contribute to secondary permeability. This area is prospective for shale and tight gas and geothermal energy. The existence and nature of natural fractures is verified through an integrated analysis of geophysical logs (including wellbore image logs) and 3D seismic data. Wellbore image logs from 11 petroleum wells within the Penola Trough were interpreted for both stress indicators and natural fractures. A total of 507 naturally occurring fractures were identified, striking approximately WNE-ESE. Fractures which are aligned in the in-situ stress field are optimally oriented for reactivation, and are hence likely to be open to fluid flow. Fractures are identifiable as being either resistive or conductive sinusoids on the resistivity image logs used in this study. Resistive fractures, of which 239 were identified, are considered to be cemented with electrically resistive cements (such as quartz or calcite) and thus closed to fluid flow. Conductive fractures, of which 268 were identified, are considered to be uncemented and open to fluid flow, and thus important to geothermal exploration. Fracture susceptibility diagrams constructed for the identified fractures illustrate that the

  6. Basin-Scale nd Isotope Gradients in South Atlantic Marine Sedimentary Records

    NASA Astrophysics Data System (ADS)

    Ran, W.; Abouchami, W.; Zahn, R.; Masque, P.

    2012-12-01

    radiogenic ɛNd values, whereas variable Holocene Pa/Th are combined to less radiogenic ɛNd values. The radiogenic seawater Nd isotope signature is entirely consistent with a predominance at the site during the LGM of a water body different from present-day NADW (ɛNd=-13). Together with existing Nd isotope records [3, 4, 5] this demonstrates the existence of a basin scale North-South Nd isotope gradient consistent with the contention, previously drawn from meridional 231Pa/230Th offsets [1], of a more prominent northward advection of southern component water. The combined 231Pa/230Th - Nd isotope systematics of existing marine sedimentary records has important implication for the significance and interpretation of these proxies as tracers of the dynamics of the Atlantic MOC which will be discussed in view of existing models. [1] Negre et al., Nature, 2010, 468, 84-88. [2] Galer et al., Mineral. Mag., 2011, 75, 883. [3] Rutberg et al., Nature, 2000, 405, 935-938. [4] Piotrowski et al., 2005, Science, 307: 1933-1938. [5] Roberts et al., 2010, Science, 327: 75-77.

  7. 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

  8. Air Pollution Source/receptor Relationships in South Coast Air Basin, CA

    NASA Astrophysics Data System (ADS)

    Gao, Ning

    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 (SoCAB) 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 (PCA), potential source contribution function (PSCF) analysis, Kohonen's neural network combined with Prim's minimal spanning tree (TREE-MAP), 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 (SCAQS). It consists of a number of gaseous and particulate pollutants analyzed from samples collected by SCAQS samplers at eight sampling sites, Anaheim, Azusa, Burbank, Claremont, Downtown Los Angeles, Hawthorne, Long Beach, and Rubidoux. Based on the information of emission inventories, meteorology 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_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_{rm x} that is subsequently transformed and collected at sampling sites. Electric power plants also contribute HNO_3 to the sampling sites. A large feedlot in the eastern region of SoCAB has been identified as the major source of NH_3. Possible contributions from other industrial sources such as smelters and incinerators were also revealed. The results of this study also suggest the possibility of DMS (dimethylsulfide) and NH_3 emissions from off-shore sediments

  9. [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.

  10. 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

  11. 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.

  12. Timing, Structural Styles, and Tectonic Significance of Neogene Basin Inversion Across the South China Sea and Indonesian Back-Arc Region

    NASA Astrophysics Data System (ADS)

    Dorobek, S. L.; Olson, C. C.

    2005-12-01

    Basin inversion is a common phenomenon in many intracontinental extensional or transtensional settings that are subjected to later contractional deformation. Numerous examples of inverted Paleogene rift basins are found in the Indonesian back-arc region and southern and western parts of the South China Sea. Inversion was widespread across the broad region, mainly began in latest Oligocene-early Miocene time, and locally continues to the present day. Most basins were fully inverted in less than 15 Myr and inversion typically involved reactivation of preexisting extensional fault systems that formed during Paleogene rifting. We examined the tectonic styles and regional timing of basin inversion across this region in order to understand the tectonic and geodynamic reasons for the inversion. The timing of regional inversion and structural styles associated with inversion reflect roughly N-S to NNW-SSE oriented intraplate compressive stress, which suggests that incipient collision of Australian continental crust along the eastern Indonesian archipelago and `South Chinese/Vietnamese' crust along the Borneo/South Palawan margin were responsible for the widespread inversion. A fundamental change from uncoupled to coupled subduction along the Indonesian trench and Borneo/South Palawan margin, coincident with the incipient subduction of continental crust along these convergent margins during latest Oligocene-early Miocene time, may explain why intraplate compressive stress was transmitted across the Indonesian back-arc and southern South China Sea (Sunda Shelf) region. Prior to late Oligocene time, subduction was essentially uncoupled and Paleogene rift basins across the Indonesian backarc and Sunda Shelf region were thermally subsiding. The rheology of Sundaland and offshore Southeast Asian continental lithosphere also was especially conducive to widespread, nearly synchronous basin inversion during Neogene time, which likely reflects the low viscosity nature of the mantle

  13. 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

  14. Geodynamic models assist in determining the South Loyalty Basin's slab location and its implications for regional topography

    NASA Astrophysics Data System (ADS)

    Clark, Stuart R.

    2010-05-01

    In the Western Pacific, two competing kinematic reconstructions exist: one with wholly westward subduction of the Pacific plate at what is now the Tonga-Kermadec trench and one combining a degree of eastward subduction under what has been termed the New Caledonia trench. New seismological observations indicate that eastward subduction could explain the existence of a fast anomaly, the hyothesised South Loyalty Basin slab, below the 660km transition zone distinct from the fast anomaly aligned with the Tonga-Kermadec slab. A plate reconstruction dated from the suggested initiation of New Caledonia subduction in the Eocene has been developed. This reconstruction is then used to predict the thermal history of the region and together provide kinematic and thermal boundary conditions for a regional mantle convection model. The model-predicted location of the South Loyalty Basin slab's location will be presented along with the location's dependence on the mantle rheological parameters and the hotspot reference frame. The implications for the topography of the region will also be discussed.

  15. Stress distribution and seismicity patterns of the 2011 seismic swarm in the Messinia basin, (South-Western Peloponnesus), Greece

    NASA Astrophysics Data System (ADS)

    Chouliaras, G.; Drakatos, G.; Pavlou, K.; Makropoulos, K.

    2013-01-01

    In this investigation we examine the local stress field and the seismicity patterns associated with the 2011-2012 seismicity swarm in the Messinia basin, south-western Peloponnesus, Greece, using the seismological data of the National Observatory of Athens (NOA). During this swarm more than 2000 events were recorded in a 12 month period by the Hellenic Unified Seismological Network (HUSN) and also by the additional local installation of four portable broadband seismographic stations by NOA. The results indicate a Gaussian distribution of swarm activity and the development of a seismicity cluster in a pre-existing seismic gap within the Messinia basin. Centroid Moment Tensor solutions demonstrate a normal fault trending northwest-southeast and dipping to the southwest primarily due to an extensional stress field. During this seismicity swarm an epicentre migration of the three largest shocks is observed, from one end of the rupture zone in the north-western part of the cluster, towards the other edge of the rupture in the south-eastern part of the cluster. This migration is found to follow the Coulomb failure criterion that predicts the advancement and retardation of the stress field and the patterns of increases and decreases of the seismicity rate (b-value) of the frequency-magnitude relation.

  16. Assessment of Permian coalbed gas resources of the Karoo Basin Province, South Africa and Lesotho, 2016

    USGS Publications Warehouse

    Schenk, Christopher J.; Brownfield, Michael E.; Tennyson, Marilyn E.; Klett, Timothy R.; Mercier, Tracey J.; Hawkins, Sarah J.; Gaswirth, Stephanie B.; Marra, Kristen R.; Finn, Thomas M.; Le, Phuong A.; Leathers-Miller, Heidi M.

    2017-02-21

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 5.27 trillion cubic feet of coalbed gas in the Karoo Basin Province.

  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. 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.

  19. 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.

  20. 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.

  1. The Palaeoproterozoic Woodlands Formation of eastern Botswana-northwestern South Africa: lithostratigraphy and relationship with Transvaal Basin inversion structures

    NASA Astrophysics Data System (ADS)

    Eriksson, P. G.; Van Der Merwe, R.; Bumby, A. J.

    1998-11-01

    The Woodlands Formation (uppermost Pretoria Group) of eastern Botswana overlies thick quartzites of the Sengoma Formation (Magaliesberg Formation) and comprises a lower unit of interbedded mudrocks and fine-grained recrystallised quartzitic sandstones, succeeded by chaotic and very coarse-grained inferred slump deposits. Within the adjacent western region of South Africa, interbedded mudrocks and quartzitic sandstones stratigraphically overlying the Magaliesberg Formation are now assigned to the lower Woodlands Formation. Within the entire region, interference folding produced by northeast-southwest (F 1 and F 3) and northwest-southeast (F 2) compression, and concomitant faulting characterised inversion of the Pretoria Group basin. This deformation is of pre-Bushveld age and affected all units in the Pretoria Group, including the uppermost Silverton, Magaliesberg and Woodlands Formations, and intrusive Marico Hypabyssal Suite (pre-Bushveld) mafic sills. The Nietverdiend lobe of the Bushveld Complex, intrusive into this succession, was not similarly deformed. Movement along the major Mannyelanong Fault in the northwest of the study area post-dated Transvaal Basin inversion, after which the "upper Woodlands" chaotic slump deposits were formed. The latter must thus belong to a younger stratigraphical unit and is possibly analogous to apparently syntectonic sedimentary rocks (Otse Group) in the Otse Basin of eastern Botswana.

  2. 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.

  3. 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.

  4. 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

  5. Formation mechanism of the Qiongdongnan basin northwest of the South China Sea-dating the sinistral slip of the Red River Fault Zone

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Jiang, J.; Xie, W.

    2010-12-01

    Locating on the northwestern margin of the South China Sea, the Qiongdongnan basin is a NE-trending rift zone in general. Bounding with the NW-trending Yinggehai basin and the Red River- East Vietnam Fault Zone to the west, the evolution of the Qiongdongnan basin bears large amounts of information about the slip of the Red River Fault zone. Combined the geological analysis with analogue modeling experiments, we suggest that the evolution of the Qiongdongnan is controlled not only by the southeastward to south southeastward extension, but also by the sinistral slip of the Red River Fault zone. The central depression of the Qiongdongnan basin is controlled mainly by the southeastward to south southeastward extension, while the southern depression developed under the combined stress filed of southeastward extension and the dextral slip along the NNW-trending Red River fault zone. The northern depression was formed by the combined effect of the sinistral slip along the Red River Fault Zone and the southeastward extension. According to the age of the shear fault starting to develop in the southwest of the Qiongdongnan basin, as well as the age for the northwestern part to develop, the sinistral slip of the Red River Fault zone began around early oligocene, later than the rifting of the Qiongdongnan basin. The sinistral slip rate of the Red River Fault zone during early Oligocene may be smaller than the displacement rate of the Qiongdongnan basin, but become reversed thereafter, which in turn caused tectonic inversion and folding along the western segment of the Qiongdongnan basin, and NW- to NNW-trending Rediel faults from late Oligocene to middle Miocene. Through the deformation history of the Qiongdongnan basin, we defined the sinistral slip stage Indochina along the Red River Fault zone from about 36Ma to 16Ma, and further a rapid slip occurring after 30Ma.

  6. A wavelet perspective on variabilities of hydrological processes in conjunction with geomorphic analysis over the Pearl River basin in South China

    NASA Astrophysics Data System (ADS)

    Niu, Jun; Chen, Ji

    2016-11-01

    Basin response to precipitation variability by terrestrial hydrological processes may be manifested at different timescales and vary from one basin to another. A quantitative grasp of natural variability modulation is desirable for characterizing basin tendency or vulnerability on floods and droughts; quantification is not always straightforward, however. Using a macro-scale hydrological model, the Variable Infiltration Capacity (VIC) model, the hydrological time series (runoff, soil moisture, and evapotranspiration) were obtained for the 10 sub-basins over the Pearl River basin in South China for the period 1952-2000. A continuous wavelet transform was used to identify the characteristics of the temporal scales of basin-featured extreme events and related multiple-scale variabilities. By use of wavelet coherence analysis and rank correlation method, the cross correlations of monthly anomalies of hydrological processes were examined. The results showed that the runoff correlated most with, and the evapotranspiration had less response to, the precipitation variability. The analyzed results revealed that the attenuation effect of runoff in response to precipitation variability was mainly within the timescale of 2 yr in the Pearl River basin. The soil moisture variability can extend precipitation variation along with timescales. With understanding of the variability features of the terrestrial hydrological processes, this paper showed one geomorphic index, a basin form factor (FF), can represent the wavelet-based indices for high- and low-frequency responses to precipitation variability. It was found that, for a sub-basin with a higher FF value, precipitation variability can be represented more by runoff variability at less than 2-yr timescales; such a sub-basin is apt to have serious floods. With a lower FF value, a sub-basin has longer memory of soil moisture, leading to severe droughts during dry periods. This finding would be valuable to evaluate the tendency on

  7. 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.

  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. 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.

  11. 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

  12. 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

  13. Late Quaternary loess landscape evolution on an active tectonic margin, Charwell Basin, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Hughes, Matthew W.; Almond, Peter C.; Roering, Joshua J.; Tonkin, Philip J.

    2010-10-01

    Loess deposits constitute an important archive of aeolian deposition reflecting wider patterns of glacial atmospheric circulation, and more localised interactions between riverine source areas, loess trapping efficiency and geomorphic controls on erosion rate. Conceptual models have been formulated to explain the coeval evolution of loess mantles and associated landscapes (loess landscape models) but none apply to areas of tectonically induced base-level lowering. This study uses an age sequence of alluvial fill terraces in the Charwell Basin, north-eastern South Island New Zealand, which straddles the transpressive Hope Fault, to investigate geomorphic controls on loess landscape evolution in an active tectonic region. We hypothesize that the more evolved drainage networks on older terraces will more effectively propagate base-level lowering by way of a greater areal proportion of steep and convex hillslopes and a smaller proportion of non-eroding interfluves. Eventually, as the proportion of interfluves diminishes and hillslope convexity increases, terraces shift from being net loess accumulators to areas of net loess erosion. We investigate the nature of erosion and the geomorphic thresholds associated with this transition. Morphometric analysis of alluvial terraces and terrace remnants of increasing age demonstrated geomorphic evolution through time, with a decrease in extent of original planar terrace tread morphology and an increase in frequency of steeper slopes and convexo-concave land elements. The number of loess sheets and the thickness of loess increased across the three youngest terraces. The next oldest (ca. 150 ka) terrace remnant had the greatest maximum number of loess sheets (3) and loess thickness (8 m) but the loess mantle was highly variable. A detailed loess stratigraphic analysis and the morphometric analysis place this terrace in a transition between dominantly planar, uniformly loess-mantled landforms and loess-free ridge and valley terrain

  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.

  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. 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.

  18. 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.

  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. MoonRise: Sampling South Pole-Aitken Basin as a Recorder of Solar System Events (Invited)

    NASA Astrophysics Data System (ADS)

    Jolliff, B. L.; Shearer, C., Jr.; Gaddis, L. R.; Pieters, C. M.; Head, J. W.; Haruyama, J.; Jaumann, R.; Ohtake, M.; Osinski, G.; Papanastassiou, D. A.; Petro, N. E.; Moonrise Science Team

    2010-12-01

    The MoonRise mission, now in a phase A concept study, would launch in 2016 and return samples from the Moon’s South Pole-Aitken basin (SPA) in 2017. These samples would be used to (1) determine the chronology of SPA and test the “cataclysm” hypothesis for bombardment of the inner Solar System some hundreds of millions of years following planetary accretion, (2) investigate the deep crust and upper mantle of the Moon to better understand planetary differentiation, and (3) provide ground truth for orbital remote sensing and geophysics of the SPA basin to better understand giant basin-forming impact processes and the effects of such impacts on an early-formed planetary crust. The key objective that drives site selection for the MoonRise mission is to obtain rock samples that crystallized from the SPA impact-melt complex to date the formation of the basin. Many large impacts, however, occurred subsequent to SPA formation, and volcanic lavas erupted into the interior of SPA over several hundred million years, producing a complex set of geologic formations. Fortunately, the very same impact process also generates a rich diversity of rock types in the regolith that provide a record of all these events. Our focus for landing site selection is in the interior of SPA where the distinctive geochemical signature is strongest. This compositional signature, coupled with modeling of impact ejecta ballistic sedimentation and distribution, ensures that landing sites and sampling locations in the interior of SPA will contain abundant rock fragments derived from the original SPA melt sheet. The wealth of recent remote sensing data provides context to evaluate geologic formations and to establish provenance for the samples. Admixture of impactites derived from younger basins such as Apollo, Poincaré, Planck, Ingenii, Orientale and Schrödinger, as well as other large impact craters, will contribute to a chronology that is bounded by the earliest and the latest of the recognized

  1. Impacts of Freshwater on the Seasonal Variations of Surface Salinity in the Caspian Sea

    DTIC Science & Technology

    2010-01-01

    surface salinity and circulation in the Caspian Sea A. Birol Karaa, Alan J. Wallcraft3*, E.Joseph Metzgera, Murat Gunduz5 * Oceanography Division...term climatic effects are of particular importance in the Caspian Sea as well. For example, Rodinov(1994) relates variations in sea level to cycles...much finer horizontal resolution products is of particular importance. In addition, the general circulation in the Caspian Sea is reported to be

  2. The water quality of the River Thame in the Thames Basin of south/south-eastern England.

    PubMed

    Neal, Colin; Neal, Margaret; Hill, Linda; Wickham, Heather

    2006-05-01

    The water quality of the River Thame, a tributary of the River Thames in the Thames basin, is described in relation to point and diffuse contaminant inputs and runoff from permeable and impermeable bedrock geology with their own characteristic water quality. The data is examined to see if the market town of Aylesbury in the upper part of the catchment influences water quality. Previous studies highlighted the influence of Aylesbury sewage treatment works (STW) on soluble reactive phosphorus (SRP) concentrations in the river before and after phosphorus (P) stripping at the STW. Variations in water quality along the river are described and the study indicates that, apart from SRP, water quality determinants seem to be relatively unaffected by Aylesbury. The Thame water quality is compared with other catchment typologies and it is very similar to that of the main stem of the Thames even though the Thames is mainly Chalk groundwater fed. Differences in water quality largely link to the amount of STW effluent within the rivers and to the endmember compositions of the groundwater and near surface water sources.

  3. 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

  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. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Processing and interpretation of aeromagnetic data for the Santa Cruz Basin - Patagonia Mountains area, south-central Arizona

    USGS Publications Warehouse

    Phillips, Jeffrey D.

    2002-01-01

    In 1997, the U.S. Geological Survey (USGS) contracted with Sial Geosciences Inc. for a detailed aeromagnetic survey of the Santa Cruz basin and Patagonia Mountains area of south-central Arizona. The contractor's Operational Report is included as an Appendix in this report. This section describes the data processing performed by the USGS on the digital aeromagnetic data received from the contractor. This processing was required in order to remove flight line noise, estimate the depths to the magnetic sources, and estimate the locations of the magnetic contacts. Three methods were used for estimating source depths and contact locations: the horizontal gradient method, the analytic signal method, and the local wavenumber method. The depth estimates resulting from each method are compared, and the contact locations are combined into an interpretative map showing the dip direction for some contacts.

  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. Hydrocarbon source potential of the Tanezzuft Formation, Murzuq Basin, south-west Libya: An organic geochemical approach

    NASA Astrophysics Data System (ADS)

    El Diasty, W. Sh.; El Beialy, S. Y.; Anwari, T. A.; Batten, D. J.

    2017-06-01

    A detailed organic geochemical study of 20 core and cuttings samples collected from the Silurian Tanezzuft Formation, Murzuq Basin, in the south-western part of Libya has demonstrated the advantages of pyrolysis geochemical methods for evaluating the source-rock potential of this geological unit. Rock-Eval pyrolysis results indicate a wide variation in source richness and quality. The basal Hot Shale samples proved to contain abundant immature to early mature kerogen type II/III (oil-gas prone) that had been deposited in a marine environment under terrigenous influence, implying good to excellent source rocks. Strata above the Hot Shale yielded a mixture of terrigenous and marine type III/II kerogen (gas-oil prone) at the same maturity level as the Hot Shale, indicating the presence of only poor to fair source rocks.

  13. 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

  14. The formation and inversion of the western Greater Caucasus Basin and the uplift of the western Greater Caucasus: Implications for the wider Black Sea region

    NASA Astrophysics Data System (ADS)

    Vincent, Stephen J.; Braham, William; Lavrishchev, Vladimir A.; Maynard, James R.; Harland, Melise

    2016-12-01

    The western Greater Caucasus formed by the tectonic inversion of the western strand of the Greater Caucasus Basin, a Mesozoic rift that opened at the southern margin of Laurasia. Subsidence analysis indicates that the main phase of rifting occurred during the Aalenian to Bajocian synchronous with that in the eastern Alborz and, possibly, the South Caspian Basin. Secondary episodes of subsidence during the late Tithonian to Berriasian and Hauterivian to early Aptian are tentatively linked to initial rifting within the western, and possibly eastern, Black Sea and during the late Campanian to Danian to the opening of the eastern Black Sea. Initial uplift, subaerial exposure, and sediment derivation from the western Greater Caucasus occurred at the Eocene-Oligocene transition. Oligocene and younger sediments on the southern margin of the former basin were derived from the inverting basin and uplifted parts of its northern margin, indicating that the western Greater Caucasus Basin had closed by this time. A predominance of pollen representing a montane forest environment (dominated by Pinacean pollen) within these sediments suggests that the uplifting Caucasian hinterland had a paleoaltitude of around 2 km from early Oligocene time. The closure of the western Greater Caucasus Basin and significant uplift of the range at approximately 34 Ma is earlier than stated in many studies and needs to be incorporated into geodynamic models for the Arabia-Eurasia region.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Reservoir storage and hydrologic responses to droughts in the Paraná River basin, south-eastern Brazil

    NASA Astrophysics Data System (ADS)

    Melo, Davi de C. D.; Scanlon, Bridget R.; Zhang, Zizhan; Wendland, Edson; Yin, Lei

    2016-11-01

    Droughts are particularly critical for Brazil because of impacts on water supply and because most (70 %) of its electricity is derived from hydroelectric generation. The Paraná basin (PB), a major hydroelectric producing region with 32 % (60 million people) of Brazil's population, recently experienced the most severe drought since the 1960s, compromising the water supply for 11 million people in São Paulo. The objective of this study is to quantify linkages between meteorological and hydrological droughts based on remote sensing, modelling, and monitoring data using the Paraná River basin in south-eastern Brazil as a case study. Two major meteorological droughts were identified in the early 2000s and 2014, with precipitation 20-50 % below the long-term mean. Total water storage change estimated from the Gravity Recovery and Climate Experiment (GRACE) satellites declined by 150 km3 between April 2011 and April 2015. Simulated soil moisture storage declined during the droughts, resulting in decreased runoff into reservoirs. As a result, reservoir storage decreased by 30 % relative to the system's maximum capacity, with negative trends ranging from 17 (May 1997-April 2001) to 25 km3 yr-1 (May 2011-April 2015). Storage in upstream reservoirs is mostly controlled by natural climate forcing, whereas storage in downstream reservoirs also reflects dam operations. This study emphasizes the importance of integrating remote sensing, modelling, and monitoring data to evaluate droughts and to establish a preliminary understanding of the linkages between a meteorological and hydrological drought for future management.

  1. Persistent organic pollutants in the Olifants River Basin, South Africa: Bioaccumulation and trophic transfer through a subtropical aquatic food web.

    PubMed

    Verhaert, Vera; Newmark, Nadine; D'Hollander, Wendy; Covaci, Adrian; Vlok, Wynand; Wepener, Victor; Addo-Bediako, Abraham; Jooste, Antoinette; Teuchies, Johannes; Blust, Ronny; Bervoets, Lieven

    2017-05-15

    This study investigates the trophic transfer of persistent organic pollutants (POPs: PCBs, PBDEs, OCPs and PFASs) in the subtropical aquatic ecosystem of the Olifants River Basin (South Africa) by means of trophic magnification factors (TMFs). Relative trophic levels were determined by stable isotope analysis. POP levels in surface water, sediment and biota were low. Only ∑DDTs levels in fish muscle (1, indicating biomagnification of all detected POPs. Calculated TMFs for PCBs were comparable to TMF values reported from the tropical Congo River basin and lower than TMFs from temperate and arctic regions. For p,p'-DDT, a higher TMF value was observed for the subtropical Olifants River during the winter low flow season than for the tropical Congo river. TMFs of DDTs from the present study were unexpectedly higher than TMFs from temperate and arctic aquatic food webs. The fish species in the aquatic ecosystem of the Olifants River can be consumed with a low risk for POP contamination.

  2. 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.

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

    SciTech Connect

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

    1997-07-01

    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 southwest 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 (S{sub 1} + S{sub 2} = 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

    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.

  8. 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

  9. 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.

  10. Organochlorine and organotin compounds in Caspian seals (Phoca caspica) collected during an unusual mortality event in the Caspian Sea in 2000.

    PubMed

    Kajiwara, N; Niimi, S; Watanabe, M; Ito, Y; Takahashi, S; Tanabe, S; Khuraskin, L S; Miyazaki, N

    2002-01-01

    Polychlorinated biphenyls (PCBs), organochlorine pesticides and organotin compounds were determined in the blubber and liver of Caspian seals (Phoca caspica) found stranded on the coast of the Caspian Sea during an outbreak of canine distemper virus (CDV) in 2000. Among organochlorines analyzed, DDTs were the most dominant contaminants with concentrations ranging from 6.3 to 470 microg/g on a lipid-weight basis. Caspian seals collected in 2000 during the epizootic had higher concentrations of organochlorines than healthy individuals sampled in 1998. However, the blubber layer was generally thinner in the seals collected in 2000 than those in the previous surveys. Although compositions of organochlorine pesticides in seals suggested that the contamination status in the Caspian Sea is improving, the levels found in Caspian seals in 2000 were comparable to those in other marine mammals that have suffered from epizootics. This implies that the present status of contamination found in Caspian seals poses a risk of immunosuppression. Concentrations of butyltin compounds in livers of seals ranged from 0.49 to 17 ng/g on a wet-weight basis and octyltin compounds were below limit of detection in all the samples analyzed, suggesting less contamination by organotin compounds in the Caspian Sea.

  11. 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.

  12. Platform margins, reef facies, and microbial carbonates; a comparison of Devonian reef complexes in the Canning Basin, Western Australia, and the Guilin region, South China

    NASA Astrophysics Data System (ADS)

    Shen, Jian-Wei; Webb, Gregory E.; Jell, John S.

    2008-05-01

    Devonian reef complexes were well developed in Western Australia and South China, but no detailed direct comparison has been made between reef building in the two regions. The regions differ in several respects, including tectonic, stratigraphic and palaeoceanographic-palaeogeographic settings, and the reef building styles reflect minor differences in reef builders and reef facies. Similarities and differences between the two reef complexes provide insights into the characteristics of platform margins, reef facies and microbial carbonates of both regions. Here we present a comparison of platform margin types from different stratigraphic positions in the Late Devonian reef complex of the Canning Basin, Western Australia and Middle and Late Devonian margin to marginal slope successions in Guilin, South China. Comparisons are integrated into a review of the reefal stratigraphy of both regions. Reef facies, reef complex architecture, temporal reef builder associations, 2nd order stratigraphy and platform cyclicity in the two regions were generally similar where the successions overlap temporally. However, carbonate deposition began earlier in South China. Carbonate complexes were also more widespread in South China and represent a thicker succession overall. Platforms in the Canning Basin grew directly on Precambrian crystalline basement or early Palaeozoic sedimentary rocks, but in South China, carbonate complexes developed conformably on older Devonian siliciclastic strata. Pre-Frasnian reef facies in South China had more abundant skeletal frameworks than in Canning Basin reefs of equivalent age, and Famennian shoaling margins containing various microbial reefs may have been more common and probably more diverse in South China. However, Late Devonian platform margin types have been documented more completely in the Canning Basin. Deep intra-platform troughs (deep depressions containing non-carbonate pelagic sediments — Nandan-type successions) that developed along

  13. Lower Cretaceous anoxic conditions IN the Austral basin, south-western Gondwana, Patagonia Argentina

    NASA Astrophysics Data System (ADS)

    Richiano, Sebastián

    2014-10-01

    The reconstruction of palaeo-oxygenation levels in marine deposits from the Cretaceous has obtained a huge interest all around the world in recent years. This fascinating topic is here pointed out for the first time in the Austral Basin using the information provided by the black shales of the Río Mayer Formation, Patagonia, Argentina. The combination of sedimentology, ichnology and geochemistry (TOC, Ce anomaly and MnO content) allow the identification of three major intervals respecting the oxygen content. During the Berriasian and early Valanginian anoxic conditions prevail in the outer shelf. After that, between the late Valanginian and Hauterivian dysoxic palaeoenvironments were developed. Finally, a more oxygenated palaeoenvironment occurred since Aptian associated with a progradation of a proximal deltaic system. The identification of anoxic conditions is of much interest for the hydrocarbon research in this stratigraphical unit, which represents the most significant source rock of the Austral Basin.

  14. Modeling the Effects of Transbasin Nonlinear Internal Waves Through the South China Sea Basin

    DTIC Science & Technology

    2013-06-01

    SCS basin in the presence of an internal ocean soliton was modeled and examined. The modeling entailed the integration of a raytracing program...presence of an internal ocean soliton was modeled and examined. The modeling entailed the integration of a raytracing program with an eigenray search...Joseph. Next, I would like to acknowledge Dr. Y. T. Lin, WHOI, for sharing his three-dimensional raytracing MATLAB program. Next, I would like to

  15. 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%.

  16. 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

  17. 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.

  18. Black Sea and Caspian Sea, Symposium II, Constanta, Romania

    DTIC Science & Technology

    2007-05-01

    research on intelligence issues that distills lessons and improves Intelligence Community capabilities for policy-level and operational consumers . Th...ese proceedings are from the Second Symposium on Black Sea and Caspian Sea Security Issues conducted 18-23 May 2007 in Constanta, Romania. Th is...participants with a better understanding of the security issues . Th is publication is almost the entirety of their presentations, and the views expressed

  19. 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.

  20. Monitoring of emerging pollutants in Guadiamar River basin (South of Spain): analytical method, spatial distribution and environmental risk assessment.

    PubMed

    Garrido, Eva; Camacho-Muñoz, Dolores; Martín, Julia; Santos, Antonio; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

    2016-12-01

    Guadiamar River is located in the southwest of the Iberian Peninsula and connects two protected areas in the South of Spain: Sierra Morena and Doñana National Park. It is sited in an area affected by urban, industrial and agriculture sewage pollution and with tradition on intensive mining activities. Most of the studies performed in this area have been mainly focused on the presence of heavy metals and, until now, little is known about the occurrence of other contaminants such as emerging organic pollutants (EOPs). In this work, an analytical method has been optimized and validated for monitoring of forty-seven EOPs in surface water. The analytical method has been applied to study the distribution and environmental risk of these pollutants in Guadiamar River basin. The analytical method was based on solid-phase extraction and determination by liquid chromatography-triple quadrupole-tandem mass spectrometry. The 60 % of the target compounds were found in the analyzed samples. The highest concentrations were found for two plasticizers (bisphenol A and di(2-ethyhexyl)phthalate, mean concentration up to 930 ng/L) and two pharmaceutical compounds (caffeine (up to 623 ng/L) and salicylic acid (up to 318 ng/L)). This study allowed to evaluate the potential sources (industrial or urban) of the studied compounds and the spatial distribution of their concentrations along the river. Environmental risk assessment showed a major risk on the south of the river, mainly due to discharges of wastewater effluents.

  1. 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

  2. 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.

  3. Analysis of South China Sea Shelf and Basin Acoustic Transmission Data

    DTIC Science & Technology

    2011-09-01

    this region ( Marburger , 2004, and Bernotavicius et al., 2010). The noise was then calculated as the sum of the distributed contributors (shipping... Marburger , J.M., “Estimation of geoacoustic properties in the South China Sea shelf using a towed source and vertical line hydrophone array,” Naval

  4. 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...

  5. Magma genesis and mantle flow at a subducting slab edge: the South Sandwich arc-basin system

    NASA Astrophysics Data System (ADS)

    Leat, P. T.; Pearce, J. A.; Barker, P. F.; Millar, I. L.; Barry, T. L.; Larter, R. D.

    2004-10-01

    The intra-oceanic South Sandwich subduction system is distinctive in having a narrow slab with slab edges at its northern and southern ends. We present new geochemical data to investigate magma genesis beneath the parts of the arc and back-arc segments that lie close to the two slab edges: Kemp and Nelson seamounts at the southern edge of the South Sandwich arc, and segments E1 and E2 in the south, plus segments E9 and E10 in the north, of the East Scotia Sea. In the arc, Kemp and Nelson seamounts exhibit enhanced subduction fluxes compared to the remainder of the arc. The southernmost (Nelson) has the isotope (low Nd and high Sr isotope ratios) and elemental (ultra-high Th and Ba and high Hf/Nd ratios) characteristics of a sediment melt, or supercritical aqueous fluid, component. The more northerly (Kemp) has the same characteristics as the remainder of the arc (high Nd and slightly raised Sr isotope ratios, high Nd/Hf ratios, high Ba/Th ratios), indicative of a fluid component derived mainly from subducted crust, but has a greater mass fraction of that component than the rest of the arc. In the back-arc basin, the slab-edge segments are generally fed by more fertile mantle (E-MORB in all but E1) than the segments in the centre of the basin (N-MORB). At the edges, segments furthest from the trench (E2, E9) have small subduction components while those nearer to the trench (E1, E10) have larger subduction components and slightly more depleted mantle. We argue that several processes were important at the slab edges: roll-back of the slab, forcing sideways flow of relatively enriched mantle into the mantle wedge; convergence of the arc with the back-arc spreading centre, imparting a greater subduction component into the back-arc lavas; and anomalous heating of the subducting slab, increasing subduction fluxes and the contribution of sediment melts to the subduction component.

  6. 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.

  7. Dietary exposure to toxic and essential trace elements by consumption of wild and farmed carp (Cyprinus carpio) and Caspian kutum (Rutilus frisii kutum) in Iran.

    PubMed

    Heshmati, Ali; Karami-Momtaz, Javad; Nili-Ahmadabadi, Amir; Ghadimi, Sabah

    2017-04-01

    This study was conducted to determine and compare the concentrations of mercury (Hg), cadmium (Cd), arsenic (As), lead (Pb), nickel (Ni), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), cobalt (Co), and selenium (Se) in the muscle of wild and farmed carp (Cyprinus carpio) and wild and farmed Caspian kutum (Rutilus frisii kutum) collected from south-western Caspian Sea areas of Iran between December 2014 and March 2015. In addition, risk assessment of consumers to exposure to metals through fish consumption was estimated. In all the samples, the arsenic concentration was lower than the detection limit. The Pb, Cd, Hg and Mn concentrations were significantly higher in the wild fish samples compared to the farmed fish samples. There was no significant difference in the Fe, Zn, Cu, Co, Ni and Se concentrations of the wild and farmed carp and the wild and farmed Caspian kutum. Iron displayed the highest concentration of all the analysed metals in both the wild and farmed fish, followed by Zn and Cu. The highest Hg, Cd, Pb, Ni, Fe, Zn, Cu, Mn, Co and Se concentrations were 0.056, 0.011, 0.065, 0.120, 4.151, 3.792, 2.948, 2.690, 0.037 and 0.162 μg g(-1), respectively. The estimated daily intake of all metals was acceptable, and the hazard quotient values showed that consumption of the analysed fish posed no health risk to consumers.

  8. The heart and its valves in Caspian miniature horse: a topographic study.

    PubMed

    Paryani, M R; Gilanpour, H

    2009-02-01

    The Caspian miniature horse is one of the rare small breeds in the north of Iran. In the present study, the position of the heart and its valves were determined topographically in 4 miniature horses. We found that Caspian miniature horses have general similarities, with certain topographical variability, with other horses.

  9. 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

  10. 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

  11. Reconnaissance Waccamaw River Basin North Carolina and South Carolina. Flood Control and Related Purposes.

    DTIC Science & Technology

    1981-09-01

    compound growth rate of 0.94% as compared to a predicted compound growth rate of 0.875% for North Carolina and 0.69% for South Carolina. Projected Series E...utilization rates , food habits, age and growth , and relative abundance of selected streams and rivers. Their findings indicate the potential damage...by the nearly level topography, moderate soil infiltration rates , and seasonal high water tables. All major tributaries are broad, heavily timbered

  12. 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.

  13. Characterization of reactants, mechanisms, and species in South Coast Air Basin cloudwater. Final report

    SciTech Connect

    Richards, L.W.; Anderson, J.A.; Alexander, N.L.; Blumenthal, D.L.; Knuth, W.R.

    1987-01-01

    Sonoma Technology, Inc. (STI) conducted a study in 1985 for the California Air Resources Board in which an aircraft was used to collect cloud water, aerosol, and gas samples and to make other air-quality and meteorological measurements in stratus clouds in the Los Angeles Basin. The study continued the research on Los Angeles Basin stratus begun in 1981. The ambient concentrations of most non-volatile dissolved species in the cloud water usually decreased with time, showing that removal processes were important. Increases with time in lead and ammonia concentrations in the cloud water showed that vertical mixing was important. There was a slight tendency for nitrate concentrations to increase with time, but sulfate concentrations were relatively constant because of the very small sulfur concentrations in the clouds. The settling of droplets out of stratus clouds through air below the clouds containing ammonia and the evaporation of these relatively large droplets is suggested as a significant mechanism for the formation of large, nitrate-containing aerosol particles below the clouds.

  14. Hydrogeological typologies of the Indo-Gangetic basin alluvial aquifer, South Asia

    NASA Astrophysics Data System (ADS)

    Bonsor, H. C.; MacDonald, A. M.; Ahmed, K. M.; Burgess, W. G.; Basharat, M.; Calow, R. C.; Dixit, A.; Foster, S. S. D.; Gopal, K.; Lapworth, D. J.; Moench, M.; Mukherjee, A.; Rao, M. S.; Shamsudduha, M.; Smith, L.; Taylor, R. G.; Tucker, J.; van Steenbergen, F.; Yadav, S. K.; Zahid, A.

    2017-02-01

    The Indo-Gangetic aquifer is one of the world's most important transboundary water resources, and the most heavily exploited aquifer in the world. To better understand the aquifer system, typologies have been characterized for the aquifer, which integrate existing datasets across the Indo-Gangetic catchment basin at a transboundary scale for the first time, and provide an alternative conceptualization of this aquifer system. Traditionally considered and mapped as a single homogenous aquifer of comparable aquifer properties and groundwater resource at a transboundary scale, the typologies illuminate significant spatial differences in recharge, permeability, storage, and groundwater chemistry across the aquifer system at this transboundary scale. These changes are shown to be systematic, concurrent with large-scale changes in sedimentology of the Pleistocene and Holocene alluvial aquifer, climate, and recent irrigation practices. Seven typologies of the aquifer are presented, each having a distinct set of challenges and opportunities for groundwater development and a different resilience to abstraction and climate change. The seven typologies are: (1) the piedmont margin, (2) the Upper Indus and Upper-Mid Ganges, (3) the Lower Ganges and Mid Brahmaputra, (4) the fluvially influenced deltaic area of the Bengal Basin, (5) the Middle Indus and Upper Ganges, (6) the Lower Indus, and (7) the marine-influenced deltaic areas.

  15. 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.

  16. 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

  17. Validation and Regional Application of Three Biologically Based Urbanization Models in the South Atlantic Gulf and Tennessee River Basins

    NASA Astrophysics Data System (ADS)

    Cuffney, T. F.; Giddings, E. M.; Gregory, M. B.

    2005-12-01

    samples. The response models for ATL, BIR, and RAL were applied to 294 sites in the South Atlantic gulf and Tennessee River basins. These sites were sampled as part of the NAWQA Program over the past decade using standardized sample collection, processing, and analysis techniques. The applicability of each model was assessed based on the deviation of the derived site score from the original response model and the deviation of the UII estimated by the response model from the UII derived from census, land-use, and infrastructure data. In general, the `best' response model was the one derived from sites that had similar natural environmental characteristics (e.g., basin size and ecoregion) to the site that was being modeled. Sites with widely different natural environmental characteristics tended to have fewer taxa in common with the underlying response model and deviated more from expected results. For example, the three response models were all developed from small basins and performed poorly when applied to large rivers. There was, however, a surprising amount of correspondence among the three models derived from QQ samples. The RAL data were adequately represented by the BIR and ATL models. The ATL model was well represented by the RAL model, but not by the BIR model. The general applicability of these biological-based models of urbanization to small streams throughout the South Atlantic gulf and Tennessee River basins indicates that a general model of urban effects can be developed for this area.

  18. 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

  19. Influence of ENSO on precipitation in the East River basin, south China

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Li, Jianfeng; Singh, Vijay P.; Xu, Chong-Yu; Deng, Jingyun

    2013-03-01

    A majority of the literature analyzing the role of El Niño-Southern Oscillation (ENSO) and other teleconnections has focused on summer precipitation and on global and regional scales. Seasonal precipitation, occurring at local scale (<50,000 km2; i.e., a size of one grid cell of a typical global climate model), is of considerable importance for flood mitigation, water supply, and water resources management. In view of the relative absence of studies exploring the forces driving local precipitation, the present study examines this precipitation regime (represented by monthly precipitation data for a period of 1956-2005 from 21 gauge stations in the East River basin) as a response to well-known determining factors, i.e., Southern Oscillation Index (SOI), El Niño Modoki index (EMI), and sea surface temperature anomalies (SSTA) of Niño 1 + 2, Niño 3, Niño 4, and Niño 3.4. To achieve the goal of the study, three types of ENSO events were defined: eastern Pacific warming (EPW), central Pacific warming (CPW), and eastern Pacific cooling (EPC). Mann-Whitney U test was applied to assess whether the probabilistic behavior of precipitation in the ENSO period was different from that in the normal period. The Pearson correlation coefficient was calculated to investigate the relations between areal precipitation in the East River basin and the above-mentioned ENSO indices. Results indicated that (1) EPW caused more precipitation in autumn and winter, but less precipitation in summer. EPW even brought about extremely heavy precipitation in summer and winter. (2) CPW caused less precipitation in spring, autumn, and the annual totals. Sometimes, CPW might bring about heavy precipitation. The precipitation pattern in summer in CPW was different from the normal years. (3) EPC caused more precipitation in autumn and less precipitation in spring and winter. The middle East River basin is the region where precipitation has decreased most severely due to EPC. (4) SSTA, SOI, and EMI

  20. 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.

  1. Distribution and Diversity of Escherichia coli Populations in the South Nation River Drainage Basin, Eastern Ontario, Canada ▿

    PubMed Central

    Lyautey, Emilie; Lu, Zexun; Lapen, David R.; Wilkes, Graham; Scott, Andrew; Berkers, Tanya; Edge, Thomas A.; Topp, Edward

    2010-01-01

    We investigated the prevalence and diversity of Escherichia coli strains isolated from surface waters from multiple watersheds within the South Nation River basin in eastern Ontario, Canada. The basin is composed of mixed but primarily agricultural land uses. From March 2004 to November 2007, a total of 2,004 surface water samples were collected from 24 sampling sites. E. coli densities ranged from undetectable to 1.64 × 105 CFU 100 ml−1 and were correlated with stream order and proximity to livestock production systems. The diversity of 21,307 E. coli isolates was characterized using repetitive extragenic palindromic PCR (rep-PCR), allowing for the identification of as many as 7,325 distinct genotypes, without capturing all of the diversity. The community was temporally and spatially dominated by a few dominant genotypes (clusters of more than 500 isolates) and several genotypes of intermediary abundance (clustering between 10 and 499 isolates). Simpson diversity indices, assessed on a normalized number of isolates per sample, ranged from 0.050 to 0.668. Simpson indices could be statistically discriminated on the basis of year and stream order, but land use, discharge, weather, and water physical-chemical properties were not statistically important discriminators. The detection of Campylobacter species was associated with statistically lower Simpson indices (greater diversity; P < 0.05). Waterborne E. coli isolates from genotypes of dominant and intermediary abundance were clustered with isolates obtained from fecal samples collected in the study area over the same period, and 90% of the isolates tested proved to share genotypes with fecal isolates. Overall, our data indicated that the densities and distribution of E. coli in these mixed-use watersheds were linked to stream order and livestock-based land uses. Waterborne E. coli populations that were distinct from fecal isolates were detected and, on this basis, were possibly naturalized E. coli strains. PMID

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. Morphology, sedimentary features and evolution of a large palaeo submarine canyon in Qiongdongnan basin, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Xiangquan; Fairweather, Luke; Wu, Shiguo; Ren, Jianye; Zhang, Hongjie; Quan, Xiayun; Jiang, Tao; Zhang, Cheng; Su, Ming; He, Yunlong; Wang, Dawei

    2013-01-01

    The large Miocene-aged palaeo canyon that extents through the Qiongdongnan basin (QDNB) and Yinggehai basin (YGHB) of Northern South China Sea has been of considerable interest both economically and scientifically over the past decade. Stemmed from this, significant research has been employed into understanding the mechanism for its existence, incision, and sedimentary fill, yet debate remains. In the first case the canyon itself is actually quite anomalous. Alone from the size (over 570 km in length and more than 8 km in width (Yuan et al., 2009)), which is considerably more than most ancient deep-water channels (REFS), the canyon's sedimentary fill is also distinctly different. Some explanations have been given to explain the canyon's origin and existence, these include increased sediment supply from the Red River which is genetically linked to uplift of the Tibetan Plateau, lowstand turbidite and mass-transport activity, reactivation and dextral displacement of the Red River Fault zone inducing erosive gravity-flows, regional tilt of the QDNB and YGHB, paleo-seafloor morphology and seal-level fluctuations. With the application of new data obtained from interpretations of a large number of 2D seismic profiles, core and well log data, and tectonic and sedimentary analysis this contribution aims to: (1) Present models to explain the Canyon's sedimentary fill and basin plain deposits, which provided significant understanding of processes pre-, syn- and post-incision and; (2) review the plausibility and likelihood of each of the controlling mechanisms, hoping to shed light on this controversial aspect. We conclude that the final erosive event that shaped the canyon is dated at 5.5 Ma. The Canyon's unusual fill is a product of variation in the interaction between turbidity currents and MTD that blocked the canyon's axis, and the reduction in gravity flow energy through time; and therefore the complete succession represents one major erosive and cut event at 5.5 Ma and

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Geochemistry of the sedimentary rocks from the Nanxiong Basin, South China and implications for provenance, paleoenvironment and paleoclimate at the K/T boundary

    NASA Astrophysics Data System (ADS)

    Yan, Yi; Xia, Bin; Lin, Ge; Cui, Xuejun; Hu, Xiaoqiong; Yan, Pin; Zhang, Faqiang

    2007-04-01

    Cretaceous and Tertiary clastic sedimentary rocks from the Nanxiong Basin, South China have been analyzed to constrain their provenance, depositional climate and environment. Evidence from discrimination diagrams for sedimentary provenance and tectonic setting show that the Nanxiong Basin sediments were derived from typical continental sources. Geochemical signatures (e.g. Eu/Eu *, Th/Ti, La/Ti, Ta/Ti, Yb/Ti and Y/Ti ratios of the claystone) are nearly constant, suggesting the provenance of the Nanxiong Basin remained similar throughout the Late Cretaceous to Early Paleocene (83-56 Ma). In contrast Rb/Ti, Cs/Ti ratios and TOC and CaCO 3 concentrations require an obvious change in climate across the Late Cretaceous and Early Paleocene boundary. Singularly higher CaCO 3 contents and lower TOC values and Rb/Ti, Cs/Ti ratios in the Late Cretaceous indicate that a long period extreme dry climate occurred at that time in South China. Rb/Ti, Cs/Ti ratios and TOC values escalated and CaCO 3 contents decreased in the Early Paleocene suggesting that the climate became relatively wet, which resulted in greater vegetation cover. The lasting extreme dry climate in the Late Cretaceous may provide a clue to the extinction of the dinosaurs in the Nanxiong Basin.

  17. 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.

  18. 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.

  19. Results of the Caspian Sea satellite survey: internal wave climate

    NASA Astrophysics Data System (ADS)

    Mityagina, Marina I.; Lavrova, Olga Yu.

    2016-10-01

    Results of satellite observations of surface manifestations of internal waves in the Caspian Sea are presented. Our work produced data on a spatial and temporal variability of internal waves of non-tidal origin via their surface manifestations. By using high-resolution satellite data, we were able to get a clear picture of generation, propagation and interaction of internal wave packets and significantly broadened our insights on the physics and geography of internal waves in the World Ocean. The large amount of the data available allowed us to make some generalizations and obtain statistically significant results on a spatial and temporal variability of various internal wave surface manifestations in satellite images. We discovered numerous diverse instances of internal wave manifestations in satellite images of the Caspian Sea. We further demonstrated that this observed diversity of internal wave behavior is due to a diversity of their generation mechanisms and indicates the complexity of the dynamic environment in the region. We put together a detailed map of spatial distribution of surface manifestations of the internal waves in the Caspian Sea. We revealed a seasonal and inter-annual variability of wave activity, identified main regions of the internal wave localization for each season and revealed causes of a spatial inhomogenity of internal wave packet manifestations. Possible factors leading to the generation of non-tidal internal waves are determined on the basis of joint analysis of available satellite remote sensing data of the sea surface in microwave, visible (VIS) and infra-red (IR) ranges complemented by contact measurements.

  20. Core facies, petrology, and permeability of Tirrawarra Sandstone, Moorari Field, Cooper Basin, South Australia

    SciTech Connect

    Bever, J.M.; Carroll, P.G.; Wild, E.W.; Williams, B.P.J.

    1988-01-01

    The oil and gas-bearing Tirrawarra Sandstone lies in the basal section of the Cooper basin sequence, which is largely Permian in age. The sandstone is characteristically thick, but both interfingers with and conformable overlies glacio-lacustrine diamictites and varvites of the late Carboniferous-Early Permian Merrimeleia Formation. The Tirrawarra Sandstone has previously been interpreted as being deposited in a glacio-fluvial braided river environment. The sandstone produces high gas:oil-ratio oil at the Moorari field, from depths of 9,400 ft below sea level. Appraisal and development of the field has been hampered by the patchy distribution of reservoir quality sandstone. This study investigated the cause of reservoir quality variations. For seven cored wells, core facies analysis, core plug porosity/permeability, petrology, and wireline logs were all matched and compared. The results are as follows. (1) Facies states (grain size and bed form) largely control permeability distribution in the Tirrawarra Sandstone at the Moorari field, such that horizontally bedded medium-coarse sandstones are consistently more permeable than cross-bedded equivalents. (2) Diagenesis levels are high and include extensive silica cement and patchy kaolinite and siderite cements. However, diagenesis rarely operates independently of original depositional fabric. (3) An association between depositional environment and permeability is recognizable, with medial bars in particular providing better reservoir quality.

  1. 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.

  2. 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.

  3. 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.

  4. 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).

  5. 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.

  6. Composition, structure, origin, and evolution of off-axis linear volcanic structures of the Brazil Basin, South Atlantic

    NASA Astrophysics Data System (ADS)

    Skolotnev, S. G.; Peive, A. A.

    2017-01-01

    The paper considers the conditions and mechanisms of the formation of linear volcanic structures in the Brazil Basin, South Atlantic. Among these objects, those related to the ascent of deep mantle plumes predominate. It is shown that the ascent of melts from plume sources leads to the formation of (a) hot spot tracks in the form of linear volcanic ridges and (b) active hot lines in the form of submarine mountain chains with trends differing from those of hot spot tracks and with a more variable character of the age distribution of volcanic rocks. Fault tectonics affects the character of plume activity. In addition, plume material from a hot spot area is dragged by a moving plate as a flow or a sublithospheric lens, which leads to the long-term existence of particular independent segments of linear structures and sometimes to late volcanism reactivation within their limits. Decompression melting of the asthenospheric mantle in zones where thin lithosphere undergoes tension causes the formation of passive hot lines. The main mantle source for the considered volcanic rocks was a mixture of DMM and HIMU mantle components, with the latter abruptly dominating. In marginal oceanic regions, the EM1 component is also present (the EM2 component is found more rarely) within fragments of tectonically delaminated continental mantle that was trapped by the oceanic mantle during the breakup of Gondwana.

  7. 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.

  8. Air quality modeling in the South Coast Air Basin of California: what do the numbers really mean?

    PubMed

    Carreras-Sospedra, Marc; Dabdub, Donald; Rodríguez, Marco; Brouwer, Jacob

    2006-08-01

    This study evaluates air quality model sensitivity to input and to model components. Simulations are performed using the California Institute of Technology (CIT) airshed model. Results show the impacts on ozone (O3) concentration in the South Coast Air Basin (SCAB) of California because of changes in: (1) input data, including meteorological conditions (temperature, UV radiation, mixing height, and wind speed), boundary conditions, and initial conditions (ICs); and (2) model components, including advection solver and chemical mechanism. O3 concentrations are strongly affected by meteorological conditions and, in particular, by temperature. ICs also affect O3 concentrations, especially in the first 2 days of simulation. On the other hand, boundary conditions do not significantly affect the absolute peak O3 concentration, although they do affect concentrations near the inflow boundaries. Moreover, predicted O3 concentrations are impacted considerably by the chemical mechanism. In addition, dispersion of pollutants is affected by the advection routine used to calculate its transport. Comparison among CIT, California Photochemical Grid Model (CALGRID), and Urban Airshed Model air quality models suggests that differences in O3 predictions are mainly caused by the different chemical mechanisms used. Additionally, advection solvers contribute to the differences observed among model predictions. Uncertainty in predicted peak O3 concentration suggests that air quality evaluation should not be based solely on this single value but also on trends predicted by air quality models using a number of chemical mechanisms and with an advection solver that is mass conservative.

  9. Mineral composition of sedimentary matter in the Caspian Sea

    NASA Astrophysics Data System (ADS)

    Lukashin, V. N.; Lisitzin, A. P.; Dara, O. M.; Kozina, N. V.; Klyuvitkin, A. A.; Novigatsky, A. N.

    2016-11-01

    Data on the mineral composition of sedimentary matter and its fluxes in the sediment system of the Caspian Sea are presented. River runoff, aerosols, particulate matter from sediment traps, and the upper layer (0-1 cm) of bottom sediments are considered. The contents of detrital minerals (quartz, albite, and K-feldspar), clay minerals (illite, chlorite, and kaolinite), and carbonates (calcite, Mg-calcite, dolomite, aragonite, and rhodochrosite) are determined. Gypsum was found in bottom sediments but is absent in the other object of the sediment system.

  10. 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.

  11. 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

  12. Ecohydrological implications of runoff harvesting in the headwaters of the Thukela River basin, South Africa

    NASA Astrophysics Data System (ADS)

    De Winnaar, Gary; Jewitt, Graham

    Hydrological regimes have an important influence on biodiversity, structure, and functioning of aquatic ecosystems. Unforeseen circumstances, both hydrologically and ecologically, caused by potential adoption and expansion of runoff harvesting innovations is of particular concern to water resource planners, as downstream river systems are likely to be adversely affected. This paper provides methods for determining the influence that large-scale adoption of runoff harvesting could have on downstream flow regimes by using a scenario-based approach, with the ACRU Agrohydrological model, to simulate the potential alteration of streamflow regimes due to runoff harvesting. Scenarios were based entirely on the spatial extent of impervious surfaces associated with rural homesteads, estimates of which were taken from current population data and used to establish the density of hypothetical runoff harvesting systems within a catchment setup. Daily streamflow simulation from nine Quaternary Catchments in the Thukela River basin provided suitable data series’ for analysis using the Indicators of Hydrological Alteration method to compute ecologically relevant hydrological parameters. The outcome of this ecohydrological study demonstrated that a relatively simple modelling exercise offers the potential to assess impacts that may arise from large-scale runoff harvesting. Results established that magnitudes of high and low flows of river flow regimes were most affected by runoff harvesting. Flow reduction was found to be most significant with low flows (up to 29%) in the case where the maximum runoff harvesting scenario was used. However, the majority of the IHA hydrological flow parameters revealed only slight impacts, even under circumstances where modelling scenarios were based on unrealistically high proportions of runoff harvesting. Increasing the spatial extent of runoff harvesting is thus expected to have a much greater impact at smaller spatial scales; water resources of

  13. 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.

  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. Early Cambrian Relief Sandstone, Officer basin, south Australia - An example of secondary porosity development

    SciTech Connect

    Gaugham, C.J.; Warren, J.K. )

    1990-05-01

    The Lower Cambrian Relief Sandstone has been drilled and cored at seven locations in the eastern Officer basin, central Australia. Core, well log, petrographic, and x-ray diffraction analyses have been used to subdivide the Relief Sandstone into stratigraphic units and individual depositional environments, and to determined controlling factors on known reservoir distribution and quality. Interest in the Relief Sandstone as a potential economic oil-bearing sandstone is supported by excellent reservoir quality (up to 26.5% porosity and 4,839 md permeability). Potential source rocks are found above, below and interfingering with the Relief Sandstone. There are several occurrences of live oil bleeding from vugs and fractures in a stratigraphically higher carbonate. Traces of oil in the Relief sands and the presence of live oil in relatively close proximity suggests that the Relief Sandstone could host an economic oil accumulation. The majority of the Relief Sandstone was deposited in eolian or braided fluvial environments, with some alluvial fan sedimentation in the east, and tidal- to shallow-marine deposition in the west. Distribution of reservoir-quality sands is bimodal. In the east porosity and permeability for the most part are very poor to average. In the west, porosity and permeability are generally good to excellent. The bulk of the economic porosity is secondary, a result of dissolution of cement and matrix, with minor porosity from leaching of grains. The lower reservoir quality in the east is due to diagenesis associated with compaction and authigenic illite. Grain packing with suturing and silica overgrowths have reduced primary porosity to noneconomic levels. Permeability has been reduced by these processes and by the blocking of pore throats with authigenic illite. In the west, the porosity and permeability are high and generally due to dissolution of clay cement and primary matrix.

  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. Air quality impacts of distributed power generation in the South Coast Air Basin of California 1: Scenario development and modeling analysis

    NASA Astrophysics Data System (ADS)

    Rodriguez, M. A.; Carreras-Sospedra, M.; Medrano, M.; Brouwer, J.; Samuelsen, G. S.; Dabdub, D.

    Distributed generation (DG) is generally defined as the operation of many small stationary power generators throughout an urban air basin. Although DG has the potential to supply a significant portion of the increased power demands in California and the rest of the United States, it may lead to increased levels of in-basin pollutants and adversely impact urban air quality. This study focuses on two main objectives: (1) the systematic characterization of DG installation in urban air basins, and (2) the simulation of potential air quality impacts using a state-of-the-art three-dimensional computational model. A general and systematic approach is devised to construct five realistic and 21 spanning scenarios of DG implementation in the South Coast Air Basin (SoCAB) of California. Realistic scenarios reflect an anticipated level of DG deployment in the SoCAB by the year 2010. Spanning scenarios are developed to determine the potential impacts of unexpected outcomes. Realistic implementations of DG in the SoCAB result in small differences in ozone and particulate matter concentrations in the basin compared to the baseline simulations. The baseline accounts for population increase, but does not consider any future emissions control measures. Model results for spanning implementations with extra high DG market penetration show that domain-wide ozone peak concentrations increase significantly. Also, air quality impacts of spanning implementations when DG operate during a 6-h period are larger than when the same amount of emissions are introduced during a 24-h period.

  2. Effects of land use and water management on water quality in the western South New River Canal basin : southeast Florida, 1974-75

    USGS Publications Warehouse

    Waller, B.G.

    1978-01-01

    The South New River Canal (C-11) basin between water-control structures S-9 and S-13 is an area that is primarily undeveloped and the system of waterways within the basin is highly controlled for water-management purposes. Most of the recharge to the canals is by induced ground-water inflow and seepage. The chemical character of the surface and ground waters in inundated areas is mixed calcium-bicarbonate and sodium-chloride type. Inorganic nitrogen concentrations in surface waters are slightly higher in developed areas than in undeveloped areas. Concentrations of inorganic nitrogen in ground water in drained areas are 2-4 times greater than in undeveloped inundated areas. Average orthophosphate concentrations are uniformly low (0.01 to 0.03 milligrams per liter) throughout the basin. Total residue concentrations are fairly uniform throughout the basin and fluctuate primarily in response to hydrologic conditions. Runoff and load-discharge indices indicated that the loads of inorganic nitrogen, total residue, and phosphorus, and the discharge per unit of land drained were uniform throughout most of the basin. (Woodard-USGS)

  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. 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.

  5. Multi Proxy Approach to Discriminate Groundwater Vulnerability to Contamination: Thirumanimuttar Sub Basin, South India

    NASA Astrophysics Data System (ADS)

    Srinivasamoorthy, K.; Murugesan, V.; Gopinath, S.; Hydrogeochemistry Group

    2013-05-01

    The study area Thirumanimuttar sub-basin is one of the major tributaries of river Cauvery in southern part of India, facing serious problem both in quality and quantity due to the increasing in demand associated with rapid population growth, agricultural and industrial activities. A total of 148 groundwater samples were collected from bore wells for Pre monsoon (PRM) and Post monsoon (POM) seasons to identify groundwater vulnerability to pollution and related geochemical process. The water is neutral to alkaline in nature with an average pH of 7.37. Higher electrical conductivity (EC) were noted in western and mid-downstream parts of the study area. Higher NO3- observed during POM due to the action of anthropogenic process. The piper plot reveals the dominance of Na- Cl and Na- HCO3, mixed Ca - Na - HCO3, mixed Ca - Mg - HCO3 and Ca - SO4 facies. The (Ca +Mg) vs TZ+ plot reveals higher Ca and Mg due to silicate weathering from aquifers. Saturation index of silicate, carbonate and fluoride minerals indicates oversaturation and equilibrium state. Groundwater samples were also analysed for stable isotopes [Oxygen (18O), Hydrogen (2H or Deuterium)] and trace elements like Al, Ni and Pb. The study reveals groundwater undergone evaporation prior infiltration. The d-excess of the groundwater varied between -4.89 to 10.08 ‰ indicating water undergone strong evaporation during recharge. The isotope ratios signify ionic increases along groundwater flow path. The water type's classified 5 distinct groups with low EC and highly depleted isotopes to very high EC with enriched stable isotopic composition indicating longer residing groundwater. Trace element study indicates Al, Ni and Pb exceeding acceptable limit by WHO, 1994. The spatial plot shows higher Cr due to textile dyeing units. Residual Sodium Carbonate value indicates samples not suitable for irrigation purposes. Higher sodium percentage is noted during PRM. Higher sodium adsorption ratio observed during POM

  6. 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

    2015-07-09

    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.

  7. 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.

  8. 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

  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. Nutrient cycling in the south east Levantine basin of the eastern Mediterranean: Results from a phosphorus starved system

    NASA Astrophysics Data System (ADS)

    Krom, M. D.; Woodward, E. M. S.; Herut, B.; Kress, N.; Carbo, P.; Mantoura, R. F. C.; Spyres, G.; Thingstad, T. F.; Wassmann, P.; Wexels-Riser, C.; Kitidis, V.; Law, C. S.; Zodiatis, G.

    2005-11-01

    The south east Levantine basin of the eastern Mediterranean is a uniquely P starved system with a nitrate:phosphate ratio in the deep water of 25-28:1, a PON:POP ratio of 27-32:1 and a DON:DOP UV ratio of ˜100:1 (which probably represents a DON:DOP TOTAL of ˜50:1). The C:N:P ratio of nutrients accumulated in the deep water from decomposed organic matter was 106:8.5-10.8:0.34-0.43 similar to the measured ratios for dissolved and particulate organic matter and much higher than the Redfield ratio. It is concluded that the P limitation of the eastern Mediterranean is due to the lack of P within the system and not in the preferential removal of P relative to N. Results from the first extensive deployment of on-board nanomolar nutrient measurements in this low nutrient low chlorophyll system showed that free ammonia (50-80 nM) was present in the surface waters while nitrate was less than 10 nM, confirming the results obtained elsewhere in the CYCLOPS addition experiment results that grazing/nutrient recycling is a dominant process in this system. The total DIN:DIP ratio in the nutrient depleted waters above the chlorophyll maximum was predominantly greater than 16:1, suggesting that the system has not switched to N limitation. A primary nitrite maximum was observed immediately below the chlorophyll maximum at the top of the nutricline, which was similar to those found previously in oligotrophic ocean locations. Where nanomolar technology was deployed through the nutricline, it was found that the phosphocline started at the same depth as the nutricline for nitrate and silicate, a conclusion that would not have