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Sample records for albuquerque basin central

  1. Albuquerque Basin seismic network

    USGS Publications Warehouse

    Jaksha, Lawrence H.; Locke, Jerry; Thompson, J.B.; Garcia, Alvin

    1977-01-01

    The U.S. Geological Survey has recently completed the installation of a seismic network around the Albuquerque Basin in New Mexico. The network consists of two seismometer arrays, a thirteen-station array monitoring an area of approximately 28,000 km 2 and an eight-element array monitoring the area immediately adjacent to the Albuquerque Seismological Laboratory. This report describes the instrumentation deployed in the network.

  2. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2014

    USGS Publications Warehouse

    Beman, Joseph E.

    2015-01-01

    An initial network of wells was established by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque from April 1982 through September 1983 to monitor changes in groundwater levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. The network currently (2014) consists of 125 wells and piezometers. (A piezometer is a specialized well open to a specific depth in the aquifer, often of small diameter and nested with other piezometers open to different depths.) The USGS, in cooperation with the Albuquerque Bernalillo County Water Utility Authority, currently (2014) measures and reports water levels from the 125 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 125 sites through water year 2014 (October 1, 2013, to September 30, 2014).

  3. Computer input and output files associated with ground-water-flow simulations of the Albuquerque Basin, central New Mexico, 1901-94, with projections to 2020; (supplement one to U.S. Geological Survey Water-resources investigations report 94-4251)

    USGS Publications Warehouse

    Kernodle, J.M.

    1996-01-01

    This report presents the computer input files required to run the three-dimensional ground-water-flow model of the Albuquerque Basin, central New Mexico, documented in Kernodle and others (Kernodle, J.M., McAda, D.P., and Thorn, C.R., 1995, Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-1994, with projections to 2020: U.S. Geological Survey Water-Resources Investigations Report 94-4251, 114 p.). Output files resulting from the computer simulations are included for reference.

  4. Computer input and output files associated with ground-water-flow simulations of the Albuquerque Basin, central New Mexico, 1901-95, with projections to 2020; (supplement three to U.S. Geological Survey Water-resources investigations report 94-4251)

    USGS Publications Warehouse

    Kernodle, J.M.

    1996-01-01

    This report presents the computer input files required to run the three-dimensional ground-water-flow model of the Albuquerque Basin, central New Mexico, documented in Kernodle and others (Kernodle, J.M., McAda, D.P., and Thorn, C.R., 1995, Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-1994, with projections to 2020: U.S. Geological Survey Water-Resources Investigations Report 94-4251, 114 p.) and revised by Kernodle (Kernodle, J.M., 1998, Simulation of ground-water flow in the Albuquerque Basin, 1901-95, with projections to 2020 (supplement two to U.S. Geological Survey Water-Resources Investigations Report 94-4251): U.S. Geological Survey Open-File Report 96-209, 54 p.). Output files resulting from the computer simulations are included for reference.

  5. Water management policy for the Albuquerque Basin: What can we learn from Tucson?

    SciTech Connect

    McGuckin, M.

    1995-12-31

    Albuquerque long believed itself to be a uniquely gifted city, an enchanted exotic anomaly, a desert metropolis with plentiful water stored in the deep alluvial sand and gravel sloughed off the Sandia Mountains. That is, until 1992, when the US Geological Survey`s report entitled Geohydrologic Framework and Hydrologic Conditions in the Albuquerque Basin in Central New Mexico revealed a fault, or rather several, in their water plan. The aquifer is not all of a piece. Instead of a veritable lake underfoot, there is a series of ponds or isolated cells of water. Tucson and Albuquerque have long been, in a sense, sister cities; they share similar physical situations, but with one major difference: in Tucson it has always been understood there wasn`t much water, not in the upland Sonoran Desert. The author outlines the recent history of water management policy in Tucson with possible lessons for Albuquerque. There are some very important differences between the two cities. The first is that in Tucson, water is, for the most part, a local issue. What Albuquerque decides to do with their water affects every community along the Rio Grande, but in addition, by rippling through the economy what they decide to do impacts every community in the state. And secondly, Tucson is the terminus of the Central Arizona Project (CAP).

  6. Surface water and groundwater for growth in the Albuquerque Basin

    SciTech Connect

    Balleau, W.P.

    1995-12-31

    The current situation is one of increasing water demand for municipal, industrial, recreational and environmental maintenance. Municipal use is increasing at about 25,000 a-f/y per decade. Each new purpose of use is bidding to obtain water used by existing purposes. Agricultural water is susceptible to transfer. The theme of this conference, The Water Future of Albuquerque and Middle Rio Grande Basin, arises from concern about the aquifer`s capacity and longevity, the limitations on Rio Grande impacts, and access to water rights for future consumption. The author`s perspective on managing these three components of the situation is presented, while acknowledging other important issues about water quality, environmental goals, land subsidence, Bosque preservation and economic burdens and benefits.

  7. Application of nonlinear-regression methods to a ground-water flow model of the Albuquerque Basin, New Mexico

    USGS Publications Warehouse

    Tiedeman, C.R.; Kernodle, J.M.; McAda, D.P.

    1998-01-01

    This report documents the application of nonlinear-regression methods to a numerical model of ground-water flow in the Albuquerque Basin, New Mexico. In the Albuquerque Basin, ground water is the primary source for most water uses. Ground-water withdrawal has steadily increased since the 1940's, resulting in large declines in water levels in the Albuquerque area. A ground-water flow model was developed in 1994 and revised and updated in 1995 for the purpose of managing basin ground- water resources. In the work presented here, nonlinear-regression methods were applied to a modified version of the previous flow model. Goals of this work were to use regression methods to calibrate the model with each of six different configurations of the basin subsurface and to assess and compare optimal parameter estimates, model fit, and model error among the resulting calibrations. The Albuquerque Basin is one in a series of north trending structural basins within the Rio Grande Rift, a region of Cenozoic crustal extension. Mountains, uplifts, and fault zones bound the basin, and rock units within the basin include pre-Santa Fe Group deposits, Tertiary Santa Fe Group basin fill, and post-Santa Fe Group volcanics and sediments. The Santa Fe Group is greater than 14,000 feet (ft) thick in the central part of the basin. During deposition of the Santa Fe Group, crustal extension resulted in development of north trending normal faults with vertical displacements of as much as 30,000 ft. Ground-water flow in the Albuquerque Basin occurs primarily in the Santa Fe Group and post-Santa Fe Group deposits. Water flows between the ground-water system and surface-water bodies in the inner valley of the basin, where the Rio Grande, a network of interconnected canals and drains, and Cochiti Reservoir are located. Recharge to the ground-water flow system occurs as infiltration of precipitation along mountain fronts and infiltration of stream water along tributaries to the Rio Grande; subsurface

  8. Aeromagnetic expression of faults that offset basin fill, Albuquerque basin, New Mexico

    USGS Publications Warehouse

    Grauch, V.J.S.; Hudson, M.R.; Minor, S.A.

    2001-01-01

    High-resolution aeromagnetic data acquired over the Albuquerque basin show widespread expression of faults that offset basin fill and demonstrate that the aeromagnetic method can be an important hydrogeologic and surficial mapping tool in sediment-filled basins. Aeromagnetic expression of faults is recognized by the common correspondence of linear anomalies to surficial evidence of faulting across the area. In map view, linear anomalies show patterns typical of extensional faulting, such as anastomosing and en echelon segments. Depths to the tops of faulted magnetic layers showing the most prominent aeromagnetic expression range from 0 to 100 m. Sources related to subtler fault expressions range in depths from 200 to 500 m. We estimate that sources of the magnetic expressions of the near-surface faults likely reside within the upper 500-600 m of the subsurface. The linear anomalies in profile form show a range of shapes, but all of them can be explained by the juxta-position of layers having different magnetic properties. One typical anomaly differs from the expected symmetric fault anomaly by exhibiting an apparent low over the fault zone and more than one inflection point. Although the apparent low could easily be misinterpreted as representing multiple faults or an anomalous fault zone, geophysical analysis, magnetic-property measurements, and geologic considerations lead instead to a "thin-thick model" in which magnetic layers of different thickness are juxtaposed. The general geometry of this model is a thin magnetic layer on the upthrown block and a thick magnetic layer on the downthrown block. The thin-thick model can be represented geologically by growth faulting and syntectonic sedimentation, where relatively coarse-grained sediment (which is more magnetic than fine-grained material) has accumulated in the hanging wall. This implies that the aeromagnetic data have potential for mapping growth faults and locating concentrations of coarse-grained material

  9. Proposed expansion of the City of Albuquerque/U.S. Geological Survey ground-water-level monitoring network for the middle Rio Grande Basin, New Mexico

    USGS Publications Warehouse

    Bexfield, L.M.

    1998-01-01

    The Middle Rio Grande Basin in central New Mexico, extending from Cochiti Lake on the north to San Acacia on the south, covers an area of about 3,060 square miles. Ground-water withdrawals in the basin are concentrated in and around the city of Albuquerque. Because of rapid increases in population and associated ground-water pumpage, a network of wells was established cooperatively by the City of and the U.S. Geological Survey between April 1982 and September 1983 to monitor changes in ground-water levels throughout the basin. Expansion of this network has been identified as an essential element in plans to study the relation between surface water and ground water in the basin. An inventory of existing wells in the Albuquerque metropolitan area has brought together information on about 400 wells that either are being monitored for water levels or would be good candidates for monitoring. About 115 wells or well sites are proposed as additions to the current 128-well ground-water-level monitoring network for the Middle Rio Grande Basin. Despite the extensive network that would be created by the addition of the proposed existing wells, however, certain parts of the Albuquerque metropolitan area would remain without adequate coverage areally and/or with depth in the Santa Fe Group aquifer until the installation of the proposed new monitoring wells.

  10. Geostatistical analysis of hydraulic conductivity of the Upper Santa Fe Group, Albuquerque Basin, New Mexico

    SciTech Connect

    Ruskauff, G.J.

    1996-12-31

    A regional groundwater flow model has been developed to be used as a management tool for the Albuquerque Basin. It is crucial to recognize the impact of the inherent uncertainty in aquifer hydrogeology when applying the model, and an understanding of the effects of uncertainty can be accomplished using a probabilistic approach to address the role of natural variability of aquifer properties on management strategies. Statistical analysis shows that the hydraulic conductivity data is moderately skewed to the right, but is not lognormal. Geostatistical analysis revealed zonal anisotropy oriented due north-south, which is directly related to the flow direction of the ancestral Rio Grande which laid down the Upper Santa Fe Group deposits. The presence of multiple depositional environments within the Upper Santa Fe Group violates the assumption of stationarity. This can be circumvented by choosing the simulation search radius so that local stationarity holds, or by separating the basin into two portions to be simulated separately and then combined for flow model analysis.

  11. Albuquerque, NM, USA

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Albuquerque, NM (35.0N, 106.5W) is situated on the edge of the Rio Grande River and flood plain which cuts across the image. The reddish brown surface of the Albuquerque Basin is a fault depression filled with ancient alluvial fan and lake bed sediments. On the slopes of the Manzano Mountains to the east of Albuquerque, juniper and other timber of the Cibola National Forest can be seen as contrasting dark tones of vegetation.

  12. Three-dimensional model simulation of transient ground-water flow in the Albuquerque-Belen Basin, New Mexico

    USGS Publications Warehouse

    Kernodle, J.M.; Miller, Ryan S.; Scott, W.B.

    1987-01-01

    A three-dimensional digital model that simulates transient flow in the alluvial aquifer system underlying the Albuquerque-Belen Basin, New Mexico, was constructed as part of a regional aquifer study of the southwest alluvial basins. The model simulates hydraulic heads and changes in hydraulic heads for 1907 to 1979. Hydraulic-conductivity values used in the accepted model range from 0.25 ft/day in part of the Santa Fe Group to 50 ft/day in the fluvial deposits in the Rio Grande flood plain. The majority of the basin-fill material of the Santa Fe group of Tertiary and Quaternary age was modeled as having a horizontal hydraulic conductivity of either 30 or 40 ft/day. The simulated specific storage of the aquifer was 0.000001/ft and the simulated specific yield was 0.10. The aquifer was simulated as being vertically anisotropic with a ratio of vertical to horizontal hydraulic conductivity of 1:500. Simulations for 1976-79 indicated that of the 100,000 acre-ft of groundwater withdrawn annually from the basin-fill deposits outside of the Rio Grande flood plain, 68% was obtained from recharge around the basin margin, depletion of streams that are tributary to the Rio Grande, and the stream-aquifer system in the Rio Grande flood plain. Depletion of aquifer storage accounted for 25% of the groundwater supply to wells outside of the flood plain, and the remaining 7% was obtained by induced groundwater inflow from the Santo Domingo Basin. The model displayed an acceptable performance throughout the period of simulation. However, by the end of the simulation period, 1979, the portrayal of the Rio Grande flood-plain system as a specified hydraulic-head boundary was having adverse effects on the simulation. (Author 's abstract)

  13. Regional Survey of Structural Properties and Cementation Patterns of Fault Zones in the Northern Part of the Albuquerque Basin, New Mexico - Implications for Ground-Water Flow

    USGS Publications Warehouse

    Minor, Scott A.; Hudson, Mark R.

    2006-01-01

    Motivated by the need to document and evaluate the types and variability of fault zone properties that potentially affect aquifer systems in basins of the middle Rio Grande rift, we systematically characterized structural and cementation properties of exposed fault zones at 176 sites in the northern Albuquerque Basin. A statistical analysis of measurements and observations evaluated four aspects of the fault zones: (1) attitude and displacement, (2) cement, (3) lithology of the host rock or sediment, and (4) character and width of distinctive structural architectural components at the outcrop scale. Three structural architectural components of the fault zones were observed: (1) outer damage zones related to fault growth; these zones typically contain deformation bands, shear fractures, and open extensional fractures, which strike subparallel to the fault and may promote ground-water flow along the fault zone; (2) inner mixed zones composed of variably entrained, disrupted, and dismembered blocks of host sediment; and (3) central fault cores that accommodate most shear strain and in which persistent low- permeability clay-rich rocks likely impede the flow of water across the fault. The lithology of the host rock or sediment influences the structure of the fault zone and the width of its components. Different grain-size distributions and degrees of induration of the host materials produce differences in material strength that lead to variations in width, degree, and style of fracturing and other fault-related deformation. In addition, lithology of the host sediment appears to strongly control the distribution of cement in fault zones. Most faults strike north to north-northeast and dip 55? - 77? east or west, toward the basin center. Most faults exhibit normal slip, and many of these faults have been reactivated by normal-oblique and strike slip. Although measured fault displacements have a broad range, from 0.9 to 4,000 m, most are <100 m, and fault zones appear to

  14. Rock magnetic characterization of faulted sediments with associated magnetic anomalies in the Albuquerque Basin, Rio Grande rift, New Mexico

    USGS Publications Warehouse

    Hudson, M.R.; Grauch, V.J.S.; Minor, S.A.

    2008-01-01

    Variations in rock magnetic properties are responsible for the many linear, short-wavelength, low-amplitude magnetic anomalies that are spatially associated with faults that cut Neogene basin sediments in the Rio Grande rift, including the San Ysidro normal fault, which is well exposed in the northern part of the Albuquerque Basin. Magnetic-susceptibility measurements from 310 sites distributed through a 1200-m-thick composite section of rift-filling sediments of the Santa Fe Group and prerift Eocene and Cretaceous sedimentary rocks document large variations of magnetic properties juxtaposed by the San Ysidro fault. Mean volume magnetic susceptibilities generally increase upsection through eight map units: from 1.7 to 2.2E-4 in the prerift Eocene and Cretaceous rocks to 9.9E-4-1.2E-3 in three members of the Miocene Zia Formation of the Santa Fe Group to 1.5E-3-3.5E-3 in three members of the Miocene-Pleistocene Arroyo Ojito Formation of the Santa Fe Group. Rock magnetic measurements and petrography indicate that the amount of detrital magnetite and its variable oxidation to maghemite and hematite within the Santa Fe Group sediments are the predominant controls of their magnetic property variations. Magnetic susceptibility increases progressively with sediment grain size within the members of the Arroyo Ojito Formation (deposited in fluvial environments) but within members of the Zia Formation (deposited in mostly eolian environments) reaches highest values in fine to medium sands. Partial oxidation of detrital magnetite is spatially associated with calcite cementation in the Santa Fe Group. Both oxidation and cementation probably reflect past flow of groundwater through permeable zones. Magnetic models for geologic cross sections that incorporate mean magnetic susceptibilities for the different stratigraphic units mimic the aeromagnetic profiles across the San Ysidro fault and demonstrate that the stratigraphic level of dominant magnetic contrast changes with

  15. Caribbean basin framework, 3: Southern Central America and Colombian basin

    SciTech Connect

    Kolarsky, R.A.; Mann, P. )

    1991-03-01

    The authors recognize three basin-forming periods in southern Central America (Panama, Costa Rica, southern Nicaragua) that they attempt to correlate with events in the Colombian basin (Bowland, 1984): (1) Early-Late Cretaceous island arc formation and growth of the Central American island arc and Late Cretaceous formation of the Colombian basin oceanic plateau. During latest Cretaceous time, pelagic carbonate sediments blanketed the Central American island arc in Panama and Costa Rica and elevated blocks on the Colombian basin oceanic plateau; (2) middle Eocene-middle Miocene island arc uplift and erosion. During this interval, influx of distal terrigenous turbidites in most areas of Panama, Costa Rica, and the Colombian basin marks the uplift and erosion of the Central American island arc. In the Colombian basin, turbidites fill in basement relief and accumulate to thicknesses up to 2 km in the deepest part of the basin. In Costa Rica, sedimentation was concentrated in fore-arc (Terraba) and back-arc (El Limon) basins; (3) late Miocene-Recent accelerated uplift and erosion of segments of the Central American arc. Influx of proximal terrigenous turbidites and alluvial fans in most areas of Panama, Costa Rica, and the Colombian basin marks collision of the Panama arc with the South American continent (late Miocene early Pliocene) and collision of the Cocos Ridge with the Costa Rican arc (late Pleistocene). The Cocos Ridge collision inverted the Terraba and El Limon basins. The Panama arc collision produced northeast-striking left-lateral strike-slip faults and fault-related basins throughout Panama as Panama moved northwest over the Colombian basin.

  16. Paleomagnetic evidence for a Tertiary not Triassic age for rocks in the lower part of the Grober-Fuqua #1 well, southeastern Albuquerque Basin, New Mexico

    USGS Publications Warehouse

    Hudson, M.R.; Grauch, V.J.S.

    2003-01-01

    A sedimentary sequence penetrated in the lower part of the Grober-Fuqua #1 well in the southeastern Albuquerque Basin has previously been interpreted as either Triassic or Eocene in age. Paleomagnetic study of three specimens from two core fragments yielded a 54.5?? mean inclination of remanent magnetization relative to bedding. This inclination is like that expected in Tertiary time and is distinct from an expected low-angle Triassic inclination. Although the data are very few, when considered in combination with stratigraphic relations and the presence of a gravity low in this southeastern part of the basin, the paleomagnetic evidence favors a Tertiary age for strata in the lower part of the Grober-Fuqua #1 well.

  17. Three-dimensional model simulation of steady-state ground-water flow in the Albuquerque-Belen Basin, New Mexico

    USGS Publications Warehouse

    Kernodle, J.M.; Scott, W.B.

    1986-01-01

    As part of the Southwest Alluvial Basins study, model was constructed to simulate the alluvial aquifer system underlying the Albuquerque-Belen Basin. The model was used to simulate the steady-state flow condition assumed to have existed prior to 1960. Until this time there apparently were no long-term groundwater level changes of a significant magnitude outside the immediate vicinity of Albuquerque. Therefore, the construction of a steady-state flow model of the aquifer system based on reported hydrologic data predating 1960 was justified. During construction of the steady-state model, simulated hydraulic conductivity values were adjusted, within acceptable physical limits, until a best fit between measured or reported and computed heads at 34 control wells was achieved. The modeled area was divided into six sub-areas, or zones, within each of which hydraulic conductivity was assumed to be uniform. The model consisted of six layers for each of which simulated transmissivity was proportional to the layer thickness. Adjustments to simulated hydraulic conductivity values in the different zones resulted in final values that ranged from a low of 0.25 ft/day in the west to 50 ft/day in the eastern part of the basin. The error of the simulation, defined as the absolute difference between the computed and the measured or reported water level at the corresponding point in the physical system being modeled, ranged from 0.6 ft to 36 ft, with an average of 14.6 ft for the 34 control wells. (Author 's abstract)

  18. Estimated 2012 groundwater potentiometric surface and drawdown from predevelopment to 2012 in the Santa Fe Group aquifer system in the Albuquerque metropolitan area, central New Mexico

    USGS Publications Warehouse

    Powell, Rachel I.; McKean, Sarah E.

    2014-01-01

    Historically, the water-supply requirements of the Albuquerque metropolitan area of central New Mexico were met almost exclusively by groundwater withdrawal from the Santa Fe Group aquifer system. In response to water-level declines, the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began diverting water from the San Juan-Chama Drinking Water Project in December 2008 to reduce the use of groundwater to meet municipal demand. Modifications in the demand for water and the source of the supply of water for the Albuquerque metropolitan area have resulted in a variable response in the potentiometric surface of the production zone (the interval of the aquifer, from within about 200 feet below the water table to 900 feet or more, in which supply wells generally are screened) of the Santa Fe Group aquifer system. Analysis of the magnitude and spatial distribution of water-level change can help improve the understanding of how the groundwater system responds to withdrawals and variations in the management of the water supply and can support water-management agencies’ efforts to minimize future water-level declines and improve sustainability. The U.S. Geological Survey (USGS), in cooperation with the ABCWUA, has developed an estimate of the 2012 potentiometric surface of the production zone of the Santa Fe Group aquifer system in the Albuquerque metropolitan area. This potentiometric surface is the latest in a series of reports depicting the potentiometric surface of the area. This report presents the estimated potentiometric surface during winter (from December to March) of water year 2012 and the estimated changes in potentiometric surface between predevelopment (pre-1961) and water year 2012 for the production zone of the Santa Fe Group aquifer system in the Albuquerque metropolitan area. Hydrographs from selected piezometers are included to provide details of historical water-level changes. In general, water-level measurements used for this report were

  19. Central Mississippi River Basin LTAR site overview

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Central Mississippi River Basin (CMRB) member of the Long-Term Agro-ecosystem Research (LTAR) network is representative of the southern Corn Belt, where subsoil clay content makes tile drainage challenging and make surface runoff and associated erosion problematic. Substantial research infrastru...

  20. Petroleum potential of central Columbia basin

    SciTech Connect

    Lingley, W.S. Jr.; Walsh, T.J.

    1987-08-01

    Ten deep wildcat wells have been drilled in the 75,000 mi/sup 2/ Columbia basin. These wells penetrated Miocene Columbia River Basalt up to 11,000 ft thick and Paleogene nonmarine siltstones, claystones, shales, coals, sandstones, and volcanogenic rocks exceeding 11,000 ft in aggregate thickness. Lithic and arkosic sandstones range from several inches to more than 60 ft in thickness, average 26 ft thick, and are variedly argillaceous. Mean log-derived sandstone porosity ranges from 18% at 6000 ft to 8% at 14,000 ft drilled-depth. Mean vitrinite reflectance ranges from 0.4 to 1.3 within the siliciclastic section. Numerous wet-gas shows were logged in three wells including a 3.1 MMCFGD flow on a 10/64-in. choke with 3,965 psi FTP recorded during a test of Shell's 1-9 Burlington Northern. The Rattlesnake Hills gas field in the south-central Columbia basin produced 1.3 bcf of methane from Columbia River Basalt before depletion in 1941. The east-central basin comprises a plain and the west-central basin includes the hilly Yakima foldbelt where topography mimics structure. The foldbelt includes several northwest and southwest-trending anticlines, most of which are asymmetric, verge to the north, range from 3 to 6 mi across strike, and are longer than 60 mi along trend. These anticlines have numerous faulted surface culminations. Assuming the Paleogene section is conformable with surficial structure, the estimated range of possible in-place gas under these culminations is 40 bcf to 1 tcf. Most of these culminations have not been tested. The potential of the east-central Columbia basin remains unknown.

  1. Exploration in Ordovician of central Michigan Basin

    SciTech Connect

    Fisher, J.H.; Barratt, M.W.

    1985-12-01

    Deep wells in the central Michigan basin have provided sufficient data to define two new mappable formations - the Foster Formation and the Bruggers Formation. Recent conodont studies have corrected the age assignments of the strata containing these formations. Previously, the lower section (Foster) was classified as mostly Cambrian, and the upper unit (Bruggers) was identified as Early Ordovician. Conodont identifications indicate an Early and Middle Ordovician age for the Foster Formation and a Middle Ordovician age for the Bruggers Formation. The Michigan basin existed in embryonic form in the Late Cambrian, but the full outline of the present-day basin did not develop until Early Ordovician. Gas and condensate are produced from the Bruggers Formation as deep as 11,252 ft (3429 m). Geothermal investigations suggest that gas production is possible to the base of the Paleozoic section in the central basin (17,000 ft or 5181 m). Paleotemperatures were higher during the Paleozoic owing to 3000-4000 ft (914-1291 m) of additional sedimentary cover. Five wells are producing from the Bruggers Formation. All are deeper tests in anticlines producing from Devonian reservoirs discovered earlier. The structures are the result of vertical movements of basement fault blocks activated by regional stresses. 12 figures, 2 tables.

  2. Caribbean basin framework, 2: Northern Central America

    SciTech Connect

    Tyburski, S.A.; Gordon, M.B.; Mann, P. )

    1991-03-01

    There are four Jurassic to Recent basin-forming periods in northern Central America (honduras, Honduran Borderlands, Belize, Guatemala, northern Nicaragua): (1) Middle Jurassic-Early Cretaceous rifting and subsidence along normal faults in Honduras and Guatemala; rifts are suggested but are not well defined in Honduras by the distribution of clastic sediments and associated volcanic rocks. Rifting is attributed to the separation of Central America from the southern margin of the North American plate; (2) Cretaceous subsidence recorded by the development of a Cretaceous carbonate platform in Honduras, Guatemala, and Belize; subsidence is attributed to thermal subsidence of the rifted margins of the various blocks; (3) Late Cretaceous-Recent development of a volcanic arc along the western margin of Middle America and the northern margin of Honduras; (4) Late Cretaceous large-scale folding in Honduras, ophiolite obduction, and formation of a foredeep basin in Guatemala (Sepur trough); deformation is attributed to the collision between a north-facing arc in northern Honduras and the Nicaraguan Rise and the passive margin of Guatemala and Belize; and (5) Eocene to Recent strike-slip faulting along the present-day North American-Caribbean plate boundary in Guatemala, northern Honduras, and Belize. Strike-slip faults and basins form a California-type borderlands characterized by elongate basins that appear as half-grabens in profile. Counterclockwise rotation of the central honduras plateau, a thicker and topographically higher-than-average block within the plate boundary zone, is accommodated by rifting or strike-slip faults at its edges.

  3. Are Advecting Processes in the Vadose Zone of the Albuquerque Basin Altering the Conductive Heat Transfer Signal From Surface Temperature Change ?

    NASA Astrophysics Data System (ADS)

    Reiter, M. A.

    2004-12-01

    Temperature measurements ( T logs ) in the deep vadose zone ( about 60m to 120m depth ) of the Albuquerque Basin have been repeated over the past year at four piezometer nests. The measurements were made with a very fast time response thermistor, which allowed data to be taken every meter going down hole. This depth resolution of temperature data permits a rather detailed observation of the thermal regime in the vadose zone. At one site ( Lincoln Middle School ) the temperature profile below 20m clearly shows a conductive profile resulting from surface temperature change due to urbanization and nearby ( about 10m ) asphalt pavement. At the other three sites the cause of non-linearity in the T log is less certain. Temperature records suggest about 1 deg C increase in near surface air temperature over the past thirty years at the Albuquerque airport; although this data may also be affected by urbanization. The Tome and 98th Street sites are being approached by paved roads and urbanization. At the Tome site expressions representing horizontal advection are the statistically preferred fit to the T log from about 25m to 58m ( F statistic ). At the 98th Street site an expression representing a surface temperature step best fits the T log from 20m to about 75m; however, the temperature step (about 1 deg C to 2 deg C, 3 to 15 yr ago ) is variable between logs, and the profile of the T log with abrupt discontinuities may suggest other than just conductive heat transfer. The fourth piezometer nest at the Mesa del Sol site is the most remote of the sites considered, with as little nearby surface disturbance as might be expected for a drilling location. At depths between 30m and 70m the expressions representing surface temperature change, horizontal advection, and vertical advection, all fit the T log reasonably well. The temperature step expression suggests about 1 deg C to 1.8 deg C surface temperature increase about 13 yr to 28 yr ago. Deeper in the vadose zone, from about

  4. Hydrological trends in Congo basin (Central Africa)

    NASA Astrophysics Data System (ADS)

    Laraque, A.

    2015-12-01

    The last studies concerning some main Congo basin rivers allowed to subdivide their multi-annual flows into several homogeneous phases. As in West Africa, 1970 was the year of the major hydroclimatic event announcing a weaker flowing period. In the absence of long, reliable and available flow series in the whole Congo basin of 3,8 106km2 area, the present study concerns only the Congo River at Brazzaville/Kinshasa and two of the main tributaries of its right bank, Ubangui at Bangui and Sangha at Ouesso, with hydrologic data available from the first half of the 20th century. For Congo River, in comparison with its secular average, after an excess flow noted during the sixties, a significant drop of 10% occurs in the eighties. However, a return to normal conditions is recorded from 1995. For Ubangui and Sangha, the flows remain weaker since 1970. Within the bi-modal hydrological regimes of Sangha and Congo river, because they are equatorial, we also observe since many years a small decline of the secondary flood of april-june. This phenomenon was emphasized especially these last years and is founded in others rivers of Central Africa, where it reflects the variations of de rainfall patterns and the surfaces features. For the Congo basin, the situation is worrying because that affects the inland waterway transport. Moreover that wakes also the project of junction by a canal of the Congo and Chari basins for fighting against the hydrological decline of Lake Chad.

  5. Estimated 2008 groundwater potentiometric surface and predevelopment to 2008 water-level change in the Santa Fe Group aquifer system in the Albuquerque area, central New Mexico

    USGS Publications Warehouse

    Falk, Sarah E.; Bexfield, Laura M.; Anderholm, Scott K.

    2011-01-01

    The water-supply requirements of the Albuquerque metropolitan area of central New Mexico have historically been met almost exclusively by groundwater withdrawal from the Santa Fe Group aquifer system. Previous studies have indicated that the large quantity of groundwater withdrawal relative to recharge has resulted in water-level declines in the aquifer system throughout the metropolitan area. Analysis of the magnitude and pattern of water-level change can help improve understanding of how the groundwater system responds to withdrawals and variations in the management of the water supply and can support water-management agencies' efforts to minimize future water-level declines and improve sustainability. This report, prepared by the U.S. Geological Survey in cooperation with the Albuquerque Bernalillo County Water Utility Authority, presents the estimated groundwater potentiometric surface during winter (from December to March) of the 2008 water year and the estimated changes in water levels between predevelopment and water year 2008 for the production zone of the Santa Fe Group aquifer system in the Albuquerque and surrounding metropolitan and military areas. Hydrographs from selected wells are included to provide details of historical water-level changes. In general, water-level measurements used for this report were measured in small-diameter observation wells screened over short intervals and were considered to best represent the potentiometric head in the production zone-the interval of the aquifer, about 300 feet below land surface to 1,100 feet or more below land surface, in which production wells generally are screened. Water-level measurements were collected by various local and Federal agencies. The 2008 water year potentiometric surface map was created in a geographic information system, and the change in water-level elevation from predevelopment to water year 2008 was calculated. The 2008 water-level contours indicate that the general direction of

  6. Martian Sedimentary Basins and Central Mound Formation

    NASA Astrophysics Data System (ADS)

    Bennett, K. A.; Bell, J. F., III

    2014-12-01

    Central mounds on Mars are observed as sedimentary deposits within crater interiors, but the specific processes responsible for their formation and subsequent modification are still debated. The deposits are hypothesized to have been created by either subaerial or subaqueous processes through one of two general formation mechanisms. The prevailing hypothesis suggests that after their craters were formed, sediment filled the entire crater and was later eroded into the morphologies we observe today. Alternatively, the sediment could have been deposited as the features we observe today without any significant erosion contributing to their mound shape. We conducted a survey of central mounds that occur within craters larger than 25 km in diameter located between ± 60° latitude on Mars. We use mound locations, mound offsets within their host craters, and mound heights to address various mound formation hypotheses. The results of this survey support the hypothesis that mound sediment once filled the entire host crater and was later eroded into the features we observe today. We propose that large Martian impact craters act as simplistic sedimentary basins. These basins "catch" any sediment that is being transported through the region. Any geologic process that involves transport of material (airfall dust, explosive volcanism, impact ejecta, etc.) could have contributed to the growth of this sediment fill, although the dominant process could vary based on location. During this depositional phase, several processes (ice/frost, water, etc.) could have cemented the material; then, at some point, the environment changed from depositional to erosional, leading to the formation of isolated mounds of sediment within these craters. Our study reveals that most mounds are offset from the center of their host crater in the same direction as the regional winds. For example, the mounds in Arabia Terra are offset towards the western portion of their craters. This observation is

  7. Albuquerque's Environmental Story.

    ERIC Educational Resources Information Center

    Rosner, Joan; And Others

    This teachers' resource guide contains four sections in addition to an introduction. The first section is an interdisciplinary look at the major natural areas in and around Albuquerque. This is followed by a review of the city's cultural history and a glimpse into the interactions people of Albuquerque have had with their natural environment. The…

  8. Rock magnetic characteristics of faulted sediments with magnetic anomalies: A case study from the Albuquerque Basin, Rio Grande Rift, New Mexico (Invited)

    NASA Astrophysics Data System (ADS)

    Hudson, M. R.; Grauch, V. J.

    2009-12-01

    High-resolution airborne surveys in the Rio Grande rift have documented abundant short-wavelength, low-amplitude magnetic anomalies generated at faults within basin sediments. We present a rock magnetic study bearing on the source of a10-20-nT linear anomaly over the San Ysidro normal fault, which is well exposed in outcrop in the northern part of the Albuquerque Basin. Magnetic susceptibility (MS) values (SI vol) from 310 sites distributed through a 1200-m-thick composite section of rift-filling sediments of Santa Fe Group and pre-rift sedimentary rocks juxtaposed by the San Ysidro fault have lognormal distributions with well-defined means. These averages generally increase up section through eight map units: from 1.7E-4 to 2.2E-4 in the pre-rift Cretaceous and Eocene rocks, from 9.9E-4 to 1.2E-3 in three units of the Miocene Zia and Cerro Conejo Formations of the Santa Fe Group, and from 1.5E-3 to 3.5E-3 in three units of the Miocene-Pliocene Arroyo Ojito and Ceja Formations of the Santa Fe Group. Remanent magnetization is not important; Koenigsberger ratios are less than 0.3 for Santa Fe Group samples. Rock magnetic parameters (e.g., ARM/MS and S ratios) and petrography indicate that detrital magnetite content and its variable oxidation to maghemite and hematite are the predominant controls of magnetic property variations within the Santa Fe Group sediments. Magnetite is present in rounded detrital grains (including both homogeneous and subdivided types) and as fine inclusions in volcanic rock fragments. Santa Fe Group sediments with highest magnetic susceptibility have greatest magnetic-grain size as indicated by lowest ARM/MS ratios. Magnetic susceptibility increases progressively with sediment grain size to pebbly sand within the fluvial Arroyo Ojito Formation. In contrast, MS reaches highest values in fine to medium sands in eolian Zia Formation. Partial oxidation of detrital magnetite and resultant lower MS is spatially associated with calcite cementation

  9. Fault Networks in the Northwestern Albuquerque Basin and Their Potential Role in Controlling Mantle CO2 Degassing and Fluid Migration from the Valles Caldera

    NASA Astrophysics Data System (ADS)

    Smith, J. R.; Crossey, L. J.; Karlstrom, K. E.; Fischer, T. P.; Lee, H.; McGibbon, C. J.

    2015-12-01

    The Rio Grande rift (RGR) has Quaternary and active volcanism and faulting that provide a field laboratory for examining links between mantle degassing and faults as fluid conduits. Diffuse and spring CO2 flux measurements were taken at 6 sites in the northwestern Albuquerque Basin (NWAB) and Valles caldera geothermal system. All sites progress to the southwest from the 1.25 Ma Valles caldera, down the rift-related Jemez fault network, to intersect with the Nacimiento fault system. Mantle CO2 and He degassing are well documented at 5 of 6 sites, with decreasing 3He/4He ratios away from the caldera. The instrument used to measure CO2 flux was an EGM-4 CO2 gas analyzer (PP systems) with an accumulation chamber. Carbonic springs at Penasco Springs (PS) and San Ysidro (SY), and the carbonate-cemented Sand Hill Fault (SHF) were targeted, all near the western border of the RGR. The SHF has no spring activity, had the smallest maximum flux of all the sites (8 g/m2d), but carbonate along the fault zone (<2 m wide) attest to past CO2 flux. The other two sites are equal distance (30-40 km) between the SHF site and Valles caldera sites. These sites have active carbonic springs that precipitate travertine mounds. Our work suggests these sites reflect intersections of the Nacimiento fault with NE trending faults that connect to the Jemez fault network. The maximum diffuse flux recorded at SY (297 g/m2d) and PS (25 g/m2d) are high, especially along the fault and near springs. At SY and PS the instruments capacity was exceeded (2,400 g/m2d) at 6 of 9 springs. Interpretations indicate a direct CO2 flux through a fault-related artesian aquifer system that is connected to magmatic gases from the caldera. Maximum diffuse flux measurements of Alamo Canyon (20,906 g/m2d), Sulphur Springs (2,400 g/m2d) and Soda Dam (1,882 g/m2d) at Valles caldera geothermal sites are comparable to Yellowstone geothermal systems. We use geospatial analysis and local geologic mapping to examine

  10. Tiger Team assessment of the Sandia National Laboratories, Albuquerque

    SciTech Connect

    Not Available

    1991-05-01

    This report documents the Tiger Team Assessment of Sandia National Laboratories (SNL), Albuquerque, located in Albuquerque, New Mexico. SNL, Albuquerque, is operated by the Sandia Corporation (a wholly owned subsidiary of the American Telephone and Telegraph Company) for the US Department of Energy (DOE). The environmental assessment also included DOE tenant facilities at Ross Aviation, Albuquerque Microelectronics Operation, and the Central Training Academy. The assessment was conducted from April 15 to May 24, 1991, under the auspices of DOE's Office of Special Projects under the Assistant Secretary for Environment, Safety and Health (ES H). The assessment was comprehensive, encompassing ES H disciplines, management, self-assessments, and quality assurance; transportation; and waste management operations. Compliance with applicable federal, state, and local regulations; applicable DOE Orders; best management practices; and internal SNL, Albuquerque, requirements were assessed. In addition, an evaluation of the adequacy and effectiveness of DOE and SNL, Albuquerque management of ES H programs was conducted.

  11. CHARACTERIZATION OF OIL SHALE MINE WATERS, CENTRAL PICEANCE BASIN, COLORADO

    EPA Science Inventory

    A study was conducted to characterize the oil shale mine waters in the Piceance Basin. The study sites were Federal Prototype Lease Tracts C-a and C-b, located in the central portion of the basin. The objective was to collect water quality data in order to characterize the mine w...

  12. UV - ALBUQUERQUE NM

    EPA Science Inventory

    Brewer 109 is located in Albuquerque NM, measuring ultraviolet solar radiation. Irradiance and column ozone are derived from this data. Ultraviolet solar radiation is measured with a Brewer Mark IV, single-monochrometer, spectrophotometer manufactured by SCI-TEC Instruments, Inc....

  13. Bison basin, central Wyoming - geologic overview

    SciTech Connect

    Pinnell, M.L.

    1984-07-01

    The northeastern part of the Great Divide basin is a separate, unique, and until recently, little-explored subbasin sometimes called the Bison basin. It is bounded by the Wind River Mountains, Sweetwater-Granite Mountain foreland uplift, Lost Soldier-Wertz structure, and a little-studied very positive east-west structural arch approximately coincident with the Sweetwater-Fremont county line. A comprehensive seismic, Landsat, and subsurface geologic examination or, better, dissection of the Bison basin was initiated in 1978. Numerous oil and gas prospects were delineated by this study. Since this small, 12 by 40 mi (19 by 64 km) basin is bordered by known reserves of 260 million bbl of oil and 90 million bcf of gas, these prospects proved to be a popular target of the drill bit. At least one of these prospects appears to be productive; others are currently being drilled. The presence of major east-west wrench faults, a well-documented foreland uplift, until recently undrilled surface and subsurface structures, faults with throw measured in tens of thousands of feet, and an oil seep indicate possible additional hydrocarbon potential in the Bison basin that could exceed presently known reserves. Currently drilling wells and abundant already acquired reflection seismic data are the beginning step in an ongoing exploration program of an interesting, complex, and rewarding small basin with a lot of promise.

  14. Hydrocarbon habitat of the Tuz Golu basin, central Anatolia, Turkey

    SciTech Connect

    More, C.; Bird, P.R.; Clark-Lowes, D.D. )

    1988-08-01

    The Tuz Golu basin (TGB) of central Anatolia has been interpreted as a northwest-southeast-aligned terraced forearc basin that accumulated a Maastrichtian to Holocene, predominantly terrigenous, sedimentary succession. Evidence is presented from an integrated study incorporating all seismic, gravity, and well data for the following basin evolution. (1) Late Cretaceous sedimentation on the west of the Kirsehir block with a diverse assemblage of facies including terrestrial, possible sabkha, shallow marine carbonate and turbidite deposits; (2) eastward subduction of Neotethys beginning in the Maastrichtian and development of the Tuz Golu as a forearc basin; (3) deposition of a thick Paleocene to Eocene flysch succession; (4) late Eocene inversion of the thick flysch section along the central axis of the basin and development of flanking shallow basins; (5) late Eocene-Oligocene emergence with deposition of evaporites and red beds in a restricted basin, followed by suturing of continental blocks, uplift, and erosion; (6) dextral displacement along the Kochisar fault; (7) Oligocene-Miocene diapirism of Eocene salt along major faults in the western shallow basin; and (8) terrestrial and lacustrine sedimentation in the neotectonic TGB. Of the 22 wells drilled in the TGB, four contained oil or gas shows from formations of Paleocene to Miocene age. Potential shale source rocks occur in the Upper Cretaceous, Paleocene, and Eocene sections. Cretaceous rudist reefs and Paleocene/Eocene sandstones provide target reservoirs, while Eocene salt represents an ideal seal. Late Eocene deformation created the major trap-forming structures of the basin.

  15. Summary of U.S. Geological Survey and City of Albuquerque hydrologic investigations program

    SciTech Connect

    McAda, D.

    1995-12-31

    The US Geological Survey and Albuquerque have been cooperating in data collection programs and interpretive studies since 1982. The paper presents summaries on recently completed and ongoing projects, detailing the objectives, principal investigator, period of the project, and reports released or reports in progress on each study. Project names are: Ground-water-level monitoring network in the Albuquerque Basin; Water budget of the Rio Grande flood plain in the Albuquerque area; Modeling of groundwater flow in the Albuquerque Basin; Continuation of ground water flow modeling in the Albuquerque Basin; Evaluation of methods to quantify the hydrologic relations between the Rio Grande and the Santa Fe Group aquifer system, near Albuquerque; Aquifer compaction and land subsidence in the Albuquerque, NM area; Aquifer test at the Griegos Well Field, Albuquerque, NM; Quality of urban stormwater runoff; Rio Grande water quality; Determining accurate concentrations and loads of trace elements and other selected chemical constituents in the Rio Grande, Albuquerque, NM; Digital geophysical-log data base; and Water quality data for the Albuquerque Basin.

  16. Jurassic sedimentary basins in the Central Asian orogenic belt

    SciTech Connect

    Bebeshev, I.I.

    1995-05-01

    The principal stages of development of Jurassic sedimentary basins (from their origin to the end of their existence) in the Central Asian orogenic belt are considered. The interrelations of the basins with the surrounding paleorises are investigated. Paleogeographic maps are compiled representing the evolution of paleolandscapes and revealing their interrelations in space and time for each stage. Areas with the highest prospects for coal are found.

  17. On Restoring Sedimentary Basins for Post-Depositional Deformation - Paleozoic Basins of the Central Andes

    NASA Astrophysics Data System (ADS)

    Bahlburg, H.

    2015-12-01

    The reconstruction and interpretation of sedimentary basins incorporated into folded and thrusted mountain belts is strongly limited by the style and intensity of shortening. This problem is exacerbated if deformation is polyphasic as is the case for the Paleozoic basins in the central Andes. Some of these have been deformed by folding and thrusting during at least 3 events in the Late Ordovician, the Late Paleozoic and Cenozoic. A realistic reconstruction of the original basin dimensions and geometries from outcrops and maps appears to be almost impossible. We present results of a stepwise reconstruction of the Paleozoic basins of the central Andes by restoring basin areas and fills accounting for crustal shortening. The structurally most prominent feature of the central Andes is the Bolivian Orocline which accomodated shortening in the last 45 Ma on the order of between 300 and 500 km. In a first step basins were restored by accounting for Cenozoic rotation and shortening by deconvolving the basins using an enhanced version of the oroclinal bending model of Ariagada et al. (2008). Results were then restored stepwise for older deformation. Constraints on these subsequent steps are significantly poorer as values of shortening can be derived only from folds and thusts apparent in outcrops. The amount of shortening accomodated on unexposed and therefore unknown thrusts can not be quantified and is a significant source of error very likely leading to an underestimation of the amount of shortening. Accepting these limitations, basin restoration results in an increase in basin area by ≥100%. The volumes of stratigraphically controlled basin fills can now be redistributed over the wider, restored area, translating into smaller rates of accumulation and hence required subsidence. The restored rates conform to those of equivalent modern basin settings and permit a more realistic and actualistic analysis of subsidence drivers and the respective tectonic framework.

  18. Hydrocarbon potential of Central Monagas, Eastern Venezuela Basin, Venezuela

    SciTech Connect

    Barrios, F.; Daza, J.; Iusco, G.

    1996-08-01

    The Central Monagas area is part of the foreland sub-basin located on the southern flank of the Eastern Venezuela Basin. The sedimentary column of the Central Monagas is at least 7500 in thick and consists of Mesozoic (Cretaceous) and Cenozoic rocks. Interpretations of 60 regional seismic sections have been integrated with data from 12 existing wells, which cover an area of 1200 km{sup 2}. From these interpretations, basin-wide structure and interval isopach maps were constructed in order to aid the depiction of the basin architecture and tectonic history. The sub-basin developed on the southern flank of the Eastern Venezuela Basin is tightly linked to its evolution from a Mesozoic extensional regime into a Cenozoic compressional and strike-slip stage. The basin formed in the Middle Mesozoic by crustal extension of a rifting process. Regional northward tilting of the slab continued during the Late Cretaceous. Finally, the transpression of the Caribbean Plate during the Oligocene-Neogene induced the overprint of compressional deformation associated with the deposition of a foredeep wedge. Geochemical source rock analysis gave an average of 1.2 TOC, and R{sub o} of 0.66 indicating a mature, marine source. The modeling of the hydrocarbon generative history of the basin indicates that the oil migration started in the Middle Miocene, after the trap was formed. Analysis and mapping of reservoir rocks and seal rocks defined the effective area limits of these critical factors. The main play in the area is the extension of the Lower Oficina Formation which is the proven petroleum target in the Eastern Venezuela Basin.

  19. The Central European Permian Basins; Rheological and structural controls on basin history and on inter-basin connectivity

    NASA Astrophysics Data System (ADS)

    Smit, Jeroen; Van Wees, Jan-Diederik; Cloetingh, Sierd

    2014-05-01

    We analyse the relative importance of the major crustal-scale fault zones and crustal architecture in controlling basin formation, deformation and the structural connections between basins. The North and South Permian Basins of Central Europe are usually defined by the extend of Rotliegend sedimentary and volcanic units and not by a common tectonic origin or development. Instead, the sub-basins that together form the Permian Basins are each controlled by different structural and/or rheological controls that are inherited from Early Paleozoïc and older geodynamic processes, they are even located in different crustal/lithospheric domains. The North Permian basin is located on Baltic crust that was thinned during Late Proterozoïc - Early Paleozoïc times. South of the Thor suture, the South Permian basin and its sub-basins are located on Avalonian crust (Southern North Sea and North German Basins) and on the transition of East European cratonic and Avalonian crust (Polish Through). The size of crustal domains and of the faults that govern basin formation requires a regional-scale to assess their impact on basins and sub-basins. In the case of the Permian Basins this encompasses East Avalonia and surroundings, roughly speaking the area north of the Variscan Rheïc suture, east of the Atlantic and southwest of the Teisseyre-Tornquist line. This approach sheds light on the effects of long lived differences in crustal fabric which are responsible for spatial heterogeneity in stress and strain magnitudes and zonations of fracturing, burial history and temperature history. The focus on understanding the geomechanical control of large crustal-scale fault structures will provide the constraints and geometrical and compositional input for local models of stress and strain. Considering their fundamentally different structural and rheological controls, the Permian (sub)basins have a remarkably common history of subsidence and inversion, suggesting a more or less continuous

  20. Paluxy of the Central Basin-East Texas

    SciTech Connect

    Presley, M.W. )

    1993-09-01

    The Paluxy Formation (Lower Cretaceous) has been a consistent sandstone exploration objective in the central East Texas basin, occurring at moderate depths on the order of 5000-8000 ft with oil in reservoirs with good permeability and porosity and reserves in the range of 200,000 to 500,000 bbl per well. Since the 1940s, the pace of Paluxy field discovery has been steady, generally a new field or two every one or two years, and there is every reason to believe that there is continued potential for the Paluxy in the future. The central part of the East Texas basin, in Smith County and adjacent areas, has complex structure with numerous salt domes and intervening sediment wedges (turtles) that formed during movement of the salt. Paluxy oil and gas in this area occurs mainly in combination structural-stratigraphic traps along normal faults that cut turtles. Major exploration trends in the central basin include (1) the Lindale turtle with a number of widely spaced fields, generally with only a few wells but with relatively good per-well reserves, (2) the Tyler turtle with the largest fields and some of the most prolific Paluxy production in the central basin, (3) the Flint and Irene turtles with relatively thin sandstones and modest production, (4) the Lane Chapel turtle with some exciting new Paluxy discoveries, and (5) the rim areas of salt domes.

  1. GEOMORPHIC CONTROLS ON MEADOW ECOSYSTEMS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    Wet meadows, riparian corridor phreatophyte assemblages, and high-altitude spring-fed aspen meadows comprise a very small percentage of the total landscape of the mountain ranges in the central Great Basin however, they represent important ecological environments. We have used s...

  2. Albuquerque, New Mexico, USA: A sunbelt city rapidly outgrowing its aquifer

    SciTech Connect

    Turin, H.J.; Gaume, A.N.; Bitner, M.J.

    1997-02-01

    Albuquerque, New Mexico, is located along the Rio Grande in central New Mexico, at an elevation of 5280 feet. Albuquerque`s climate reflects its high desert setting; average annual precipitation in the basin is only 8 to 10 inches. The Albuquerque metropolitan area is part of the rapidly growing {open_quotes}sunbelt{close_quotes} region of the southwestern United States and is undergoing rapid development. The municipal, industrial, and residential water needs of the entire population are currently met by groundwater, while agricultural needs within the basin are met by surface water diverted from the Rio Grande. While the city is blessed with an extremely productive aquifer, current metropolitan area annual groundwater extractions of 170,000 acre-feet far exceed the sustainable yield of the aquifer. Continued drawdown will lead to greater pumping costs, ground surface subsidence problems, and eventual aquifer depletion. At the same time, industrial and non-point-source contamination and naturally occurring arsenic levels are raising concerns about groundwater quality. New Mexico water law has required the City to acquire surface water rights and allocations on the Rio Grande sufficient to offset estimated losses from the river induced by the City`s groundwater extraction. It has become increasingly clear that the induced recharge had been greatly overestimated, and that the City is thus not actually consuming its surface water as intended. The City, in cooperation with local, state, and federal agencies, has explored a variety of conjunctive use proposals, all designed to permit the City to use its surface water more directly. The City Council is presently considering a strategy calling for full use of the city`s surface water resources and creation of a groundwater drought reserve. Implementation of this strategy will require regulatory approval and major capital investment, both of which require political support.

  3. Delaware basin/Central basin platform margin: The development of a subthrust deep-gas province in the Permian Basin

    SciTech Connect

    Purves, W.J. ); Ting, S.C. )

    1990-05-01

    A deep-gas-prone province was identified along the Delaware basin/Central Basin platform margin, a margin conventionally interpreted to be bounded by high-angle normal or high-angle reverse structures. Redefinition of the tectonic style between the Delaware basin and the adjacent platform resulted in the identification of this Delaware basin/Central Basin platform subthrust province and a giant prospect within it. Definition of a giant-sized gas prospect in northern Pecos County, Texas, revealed that portions of this margin may be characterized by shingled, low-angle, eastward-dipping, basement involved thrust faults. Interpretations suggest that hidden, subthrust footwall structures may trend discontinuously for greater than 100 mi along this structural margin. Subthrust footwall structures formed as basinal buttress points for the Central Basin platform to climb over the Delaware basin. In this area, structural relief of over 19,000 ft over a 10-mi width is believed due to stacking of low-angle thrust sheets. Seismic resolution of this subthrust margin has been complexed by allochtonous hanging-wall gravity-glide blocks and folds and by velocity changes in overlying syn- and posttectonic sediments associated with basin-to-shelf lithofacies changes. Statistical studies indicate that this deep-gas province has a play potential of greater than 10 tcf of gas, with individual prospect sizes exceeding 1 tcfg. The prospects defined along this trend are deep (approximately 20,000 ft) subthrust structural traps that are indigenously sourced and reservoired by dual-matrix porosity. Vitrinite supported maturation modeling suggests that these subthrust structures formed prior to catagenic conversion of the oldest source rocks to oil and later to gas. Tectonically fractured Ordovician Ellenburger and Devonian sediments are considered the principal reservoirs. Shales overlying reservoir intervals form vertical seals.

  4. Late Cenozoic Basin Architecture in Central Turkey: Geodynamic Implications

    NASA Astrophysics Data System (ADS)

    Gurbuz, A.; Kazanci, N.

    2014-12-01

    The Lake Tuz basin is the largest intracontinental basin in Turkey and has hydrocarbon and industrial mineral reserves. Thus, there are several studies particularly intended for the pre-Neogene geology of the basin. However, there is not any detailed study related to the geological units of Neogene and Quaternary periods. This study aims to exhibit facies features of these units within spatial and temporal distributions according to field studies. In the other hand, the region has modelled through stratigraphically by computing more than 250 borehole data within 3D GeoScientific Information System. In light of obtained model, basement topographies of Neogene and Quaternary units has revealed. The model indicate high amounts of sedimentation during the Mio-Pliocene with a southward increasing thickness of a freshwater lake basin while it is a shallow saline lake basin today that regressed towards the north during the Plio-Quaternary. The combination of these results with regional geological and geophysical data (i.e. gravity and crustal thickness) allows geodynamic implications for central Turkey. The spatio-temporal variations of Late Cenozoic units reflect the main effect of endogenic forces that were caused due to lithospheric slab break-off and following asthenospheric upwelling under central Turkey.

  5. Stratigraphy of the Sarkisla area, Sivas basin, eastern central Anatolia

    SciTech Connect

    Bilgic, T.; Sumengen, M.; Terlemez, I.; Unay, E.; Gurbuz, M.; Erkan, E.

    1988-08-01

    The stratigraphy of the Sarkisla area, southeastern Central Anatolian Massif, is characterized by a succession of rock units ranging from late Paleocene to Pliocene in age. The Caldag group mostly consists of deep-water units and forms the base of the Tertiary rocks. However, its relation to the basement rocks is not observed in the area. This group is represented by late Paleocene-Lutetian-age turbiditic pyroclastics and limestones, andesitic lavas and pyroclastics topped with reefal limestones, and turbiditic limestones and pyroclastics alternating with limestone blocks. During Lutetian to early Priabonian time, shallow marine clastics were deposited along the southern margin of the basin, while continental clastics and platform limestones accumulated along the northern margin. Late Priabonian to early Oligocene time is represented by gypsiferous deposits followed by late Oligocene-age fluvial clastics. The gypsiferous deposits conformably overlie the shallow marine formations but rest on the Caldag group unconformably. During early to middle Miocene time, alternating lacustrine limestones, gypsum, and basalts formed on the fluvial clastics; to the north, basalts formed on the platform limestones. The uppermost sequence of the basin, composed of Tortonian-early Pliocene-age fluvial clastics, lacustrine limestones, and fan deposits, unconformably overlies the older formations. The stratigraphy of the study area is similar to the Ulukisla basin, southwestern Central Anatolian Massif. Therefore, this basin can be considered to be the prolongation of the Ulukisla basin offset by the Ecemis fault.

  6. Evolutionary model of the oblique rift basins- Central African Rifts

    NASA Astrophysics Data System (ADS)

    Yang, Kenn-Ming; Cheng, I.-Wen; Wu, Jong-Chang

    2016-04-01

    The geometry of oblique-rifting basin is strongly related with the angle (α) between the trend of rift and that of regional major extensional stress. The main purpose of this study is to investigate characteristics of geometry and kinematics of structure and tectono-stratigraphy during basin evolution of Central African Rifts (CAS). In this study, we simulated the formation of oblique-rifting basin with Particle Flow Code 3-Dimensions-(PFC 3D) and compared the simulation results with the tectonic settings of a series of basin in CAS. CAS started to develop in Early Cretaceous (130Ma) and lasted until the Late Cretaceous (85Ma-80Ma). The following collision between the African and Eurasian plates imposed compressional stress on CAS and folded the strata in the rift basins. Although the characteristics of rift basin formation remain controversial, palinspastic sections constructed in this study show that, in the Early Cretaceous, the rift basins are mainly characterized by normal faults and half-grabens. In the Late Cretaceous, the morphology of the rift basins was altered by large-scaled tectonic compression with the active Borogop Fault of regional scale. Also, en echelon trend of normal faults in the basins were measured and the angles between the trend with that of the rift axes of each basin were demonstrated, indicating that the development of CAS was affected by the regional extensional stress with a dextral component during the rifting process and, therefore, the rift basins were formed by oblique-rifting. In this study, we simulated the oblique-rifting basin model of various α with Particle Flow Code 3-Dimensions-(PFC 3D). The main theory of PFC 3D is based on the Discrete Element Method (DEM), in which parameters are applied to every particle in the models. We applied forces acting on both sides of rift axis, which α are 45°, 60°, 75° and 90° respectively, to simulate basin formation under oblique-rifting process. The study results of simulation

  7. Characteristics and properties of the basin-fill aquifer determined from three test wells west of Albuquerque, Bernalillo County, New Mexico

    USGS Publications Warehouse

    Wilkins, D.W.

    1987-01-01

    Three test wells were drilled west of Albuquerque; two are on the mesa west of the city, the third well is near the Rio Grande flood plain, west of the river. Test well 1, was drilled to a depth of 1,204 ft. Transmissivity of perforated intervals in the alluvial zone (980-1121 ft) ranged from 3.1 to 3.9 ft sq/day, and horizontal hydraulic conductivity from .02 to .03 ft/day. Vertical hydraulic conductivity of the semiconfining layer between the alluvial and volcanic zones is estimated to range from .00031 to .0031 ft/day. Transmissivity of the volcanic zone (1139-1179 ft) is about 81 ft sq/day, and horizontal hydraulic conductivity is about 2.0 ft/day. Dissolved-iron and manganese concentrations exceed recommended constituent limits for a public water supply. Vertical flow is upward; the potentiometric surface in the volcanic zone is about 2 ft higher than in the alluvial zone. Water levels are about 883 ft below land surface. Test well 2 was drilled to a depth of 1,828 ft below land surface with seven intervals open to the aquifer. During development, fine sand and silt entered the casing, filling it to a depth of 1,500 ft. The dissolved-cadmium concentration exceeds the maximum contaminant level and the dissolved-manganese concentration exceeds the recommended constituent limit for a public water supply. The vertical flow gradient is downward; the potentiometric surface in the middle and lower zones is about 17 ft lower than in the upper zones. Depth to water in the upper zone is about 767 below land surface and in the lower two zones the depth to water is about 784 ft below land surface. Test well 3 was drilled to a depth of 1,050 ft. Only the interval from 490 to 590 ft below land surface could be used to calculate transmissivity which was about 1,300 ft sq/day; horizontal hydraulic conductivity is about 13 ft/day. Quality of water is acceptable for a public water supply. Vertical flow is downward; the potentiometric surface in the deepest interval is about 7

  8. Basement structures in the northern Tularosa Basin, central New Mexico

    SciTech Connect

    Whitebread, M.W.; Adams, D.C. . Dept. of Geological Sciences)

    1993-02-01

    A variety of geophysical data consisting of gravity and magnetic measurements, drill holes, and other geologic information have provided an analysis of basement structures within the northern Tularosa Basin of central New Mexico. Both the Laramide and Ancestral Rockies orogenies and the extension associated with the Rio Grande rift affected the structural development of this area. This area is significant in that it is the region in which the eastern boundary of the Rio Grande rift shifts 115 km eastward to the bounding fault between the Tularosa basin and the Sacramento uplift. The Tularosa basin is a large, complex structure consisting of two grabens and a horst block. At this latitude, it is probably the major Rio Grande rift structure. In fact, gravity modeling has determined that the thinnest crust (above 32 km) in the region lies beneath the north Tularosa basin. Analysis of gravity and magnetic anomaly maps identify gravity lows associated with Paleozoic or Precambrian basins. Gravity lows northeast of the Oscura uplift form a semi-continuous regional depression eastward to the late Paleozoic Pedernal uplift, a topographic feature believed to be a remnant of the Ancestral Rocky Mountains.

  9. Description of piezometers installed in the middle Rio Grande basin area, 1997-99, central New Mexico

    USGS Publications Warehouse

    Bartolino, J.R.; Rankin, D.R.

    2000-01-01

    Since 1993, the Santa Fe Group aquifer system in the Middle Rio Grande Basin, and particularly in the Albuquerque area, has been the focus of studies to further define the extent of the most productive parts of the aquifer and to gain a better understanding of how ground- water levels are changing over time. The U.S. Geological Survey, in cooperation with the New Mexico Office of the State Engineer, installed nine piezometers during 1998-99 at five sites in and near the margin of the Middle Rio Grande Basin in central New Mexico. In addition, the New Mexico Office of the State Engineer installed another nine piezometers at three sites during 1997. These piezometers allow for collection of ground-water-level data in areas for which little information is available. Most of the piezometers were constructed of 2.5-inch-diameter flush-joint polyvinyl chloride (PVC) schedule 80 casing with 10-foot stainless steel screens; the shallow piezometer at the Tome site has a 40-foot screen, and the single piezometers at the Dome Road and Phoenix Road sites have steel casing with welded joints and a 10- and a 20-foot screen, respectively. Steel casing with a locking lid covers the uppermost 2 feet of the piezometer casing. Drillers' logs and petrophysical logs were collected from the deepest borehole at each site.

  10. Upper crust beneath the central Illinois basin, United States

    USGS Publications Warehouse

    McBride, J.H.; Kolata, Dennis R.

    1999-01-01

    Newly available industry seismic reflection data provide critical information for understanding the structure and origin of the upper crust (0-12 km depth) beneath the central Illinois basin and the seismic-tectonic framework north of the New Madrid seismic zone in the central Mississippi Valley. Mapping of reflector sequences furnishes the first broad three-dimensional perspective of the structure of Precambrian basement beneath the central United States Midcontinent. The highly coherent basement reflectivity is expressed as a synformal wedge of dipping and subhorizontal reflections situated beneath the center of the Illinois basin that thickens and deepens to the northeast (e.g., 0 to ???5.3 km thickness along a 123 km south to north line). The thickening trend of the wedge qualitatively mimics the northward thickening of the Late Cambrian Mt. Simon Sandstone; however, other Paleozoic units in the Illinois basin generally thicken southward into the basin center. The seismic data also reveal an anomalous subsequence defined by a spoon-shaped distribution of disrupted reflections located along the southern margin of the wedge. The boundaries of this subsequence are marked by distinct steeply dipping reflections (possible thrust faults?) that continue or project up to antiformal disruptions of lower Paleozoic marker reflectors, suggesting Paleozoic or possibly later tectonic reactivation of Precambrian structure. The areal extent of the subsequence appears to roughly correspond to an anomalous concentration of larger magnitude upper to middle crustal earthquakes. There are multiple hypotheses for the origin of the Precambrian reflectivity, including basaltic flows or sills interlayered with clastic sediments and/or emplaced within felsic igneous rocks. Such explanations are analogous to nearby Keweenawan rift-related volcanism and sedimentation, which initiated during Proterozoic rifting, and were followed eventually by reverse faulting along the rift margins caused

  11. Sedimentation of shelf sandstones in Queen Formation, McFarland and Means fields, central basin platform of Permian basin

    SciTech Connect

    Malicse, A.; Mazzullo, J.; Holley, C.; Mazzullo, S.J.

    1988-01-01

    The Queen Formation is a sequence of carbonates, evaporites, and sandstones of Permian (Guadalupian) age that is found across the subsurface of the Central Basin platform of the Permian basin. The formation is a major hydrocarbon reservoir in this region, and its primary reservoir facies are porous shelf sandstones and dolomites. Cores and well logs from McFarland and Means fields (on the northwest margin of the Central Basin platform) were examined to determine the sedimentary history of the shelf sandstones.

  12. Structural geology investigation on Massif Central and Parisian Basin (France)

    NASA Technical Reports Server (NTRS)

    Weecksteen, G. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Band 5 gives the most information concerning the fracturing in the Massif Central and Parisian Basins. Band 6 and 7 show the fractures emphasized by forest boundaries and by the linear trace of water courses. The most remarkable information drawn from the preliminary investigation of two ERTS-1 images covering two different landscapes, a regular relief of shelving plateau bounded by cuestas having a sedimentary origin and a mountainous region built in crystalline and volcanic rocks, is that the deep structural elements under a thick sedimentary cover can be translated on the surface by indirect criteria. MSS imagery has permitted the Metz fault to be extended towards the west and shows clearly, through land use on the Rhone Valley fluvial deposit, the continuation towards the east of the carboniferous basin of St. Etienne.

  13. Eustatic control of tertiary hydrocarbon deposits, Central California borderline basins

    SciTech Connect

    Cousminer, H.L. )

    1994-04-01

    In the central California borderland basins, the Vail-Haq Cenozoic Global Eustatic Cycle appears to have influenced depositional patterns that have fundamental significance in the present distribution of hydrocarbon source and reservoir beds. Coupled with tectonic events, traps were created that now control the distribution of hydrocarbon accumulations. Seismic data combined with subsurface lithostratigraphic, biostratigraphic, and log data from wells drilled on the central California outer continental shelf (OCS) were used to date and correlate Tertiary stratigraphic sequences in the Santa Maria, Bodega-La Honda, and Point Arena basins. Benthic foraminiferal assemblages also served to reconstruct each basin's paleobathymetric history. The west coast benthic foram stages, commerically used to solve subsurface stratigraphic problems for over 60 yr, occur with planktonic microfossil groups that now serve to calibrate the provincial stages with the absolute geologic time scale. The Miocene through Pliocene stratigraphic sequences in these three depocenters are markedly similar, and record a parallel marine onlap and offlap pattern that correlates closely with the Vail-Haq Cenozoic Global Eustatic Cycle. The highstand depositional cycles are generally dominated by organic-rich sediments of good to excellent are generally dominated by organic-rich sediments of good to excellent source-bed potential. Lowstand regressive to transgressive clastic deposits have good reservoir potential. The middle Miocene siliceous Monterey Formation was deposited during maximum Tertiary global sea levels and is present in all of these basins. In addition to being a prolific source bed, the Monterey is unique in that when diagnetically altered, it fractures and also becomes an excellent hydrocarbon reservoir.

  14. 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.

  15. Holocene floods in the Central Transylvania Basin, Romania

    NASA Astrophysics Data System (ADS)

    Perşoiu, Ioana; Persoiu, Aurel

    2016-04-01

    Climatic models suggest that the inner Carpathian region (i.e., Transylvanian basin) will become wetter throughout the years and warmer in the winter, both possibly resulting in an increase of flooding frequency. This could led to increase risks for human settlements and activities, most of them being located in large floodplains crossing the region. In this context, it is essential to know and understand the frequency, magnitude and triggers of past floods in order to be able to prepare for the future. In this context, we present here a record of Holocene flooding events in the Northern and Central Transylvanian basin, based on morphological, sedimentological and chronological information obtained from the analyses of fluvial and lake sediments. The palaeoenvironental background for the fluvial dynamics is given by decadal scale stable isotope records from Sc\\varişoara Ice Cave (summer temperature) and pollen data (vegetation dynamics) from peat bogs in the region. Phases of high lake level are evident between 5800-2400, 2200-2000, 1500-1100 cal BP and over the last 700 years, and they correlate well with increased fluvial activity and flooding events at 10200, 4700, 2800, 1300 and 500 cal BP. Climatic and vegetation data suggests that these flooding events occurred during periods of warmer winter conditions and increased transport of moisture from the Mediterranean basin, conditions likely to occur in the future.

  16. Thermal springs in the Salmon River basin, central Idaho

    SciTech Connect

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

    1982-02-01

    The Salmon River basin within the study area occupies an area of approximately 13,000 square miles in central Idaho. Geologic units in the basin are igneous, sedimentary, and metamorphic rocks; however, granitic rocks of the Idaho batholith are predominant. Water from thermal springs ranges in temperature from 20.5/sup 0/ to 94.0/sup 0/ Celsius. The waters are slightly alkaline and are generally a sodium carbonate or bicarbonate type. Dissolved-solids concentrations are variable and range from 103 to 839 milligrams per liter. Estimated reservoir temperatures determined from the silicic acid-corrected silica, sodium-potassium-calcium, and sulfate-water isotope geothermometers range from 30/sup 0/ to 184/sup 0/ Celsius. Tritium concentrations in sampled thermal waters are near zero and indicate the waters are at least 100 years old. Stable-isotope data indicate it is unlikely that a single hot-water reservoir supplies hot springs in the basin. Thermal springs discharged at least 15,800 acre-feet of water in 1980. Associated convective heat flux is 2.7 x 10/sup 7/ calories per second.

  17. Wolfcampian sequence stratigraphy of eastern Central Basin platform, Texas

    SciTech Connect

    Candelaria, M.P.; Entzminger, D.J.; Behnken, F.H. ); Sarg, J.F. ); Wilde, G.L. )

    1992-04-01

    Integrated study of well logs, cores, high-resolution seismic data, and biostratigraphy has established the sequence framework of the Atokan (Early Pennsylvanian)-Wolfcampian (Early Permian) stratigraphic section along the eastern margin of the Central Basin platform in the Permian basin. Sequence interpretation of high-resolution, high-fold seismic data through this stratigraphic interval has revealed a complex progradational/retrogradational evolution of the platform margin that has demonstrated overall progradation of at least 12 km during early-middle Wolfcampian. Sequence stratigraphic study of the Wolfcamp interval has revealed details of the internal architecture and morphologic evolution of the contemporaneous platform margin. Two generalized seismic facies assemblages are recognized in the Wolfcampian. Platform interior facies are characterized by high-amplitude, laterally continuous parallel reflections; platform margin facies consist of progradational sigmoidal to oblique clinoforms and are characterized by discontinuous, low-amplitude reflections. Sequence interpretation of carbonate platform-to-basin strata geometries helps in predicting subtle stratigraphic trapping relationships and potential reservoir facies distribution. Moreover, this interpretive method assists in describing complex reservoir heterogeneities that can contribute to significant reserve additions from within existing fields.

  18. Terrestrial heat flow in the tertiary basin of central Sumatra

    NASA Astrophysics Data System (ADS)

    Da Silva Carvalho, Humberto; Purwoko; Siswoyo; Thamrin, M.; Vacquier, Victor

    1980-10-01

    Heat flow at 170 locations in the Central Tertiary basin of Sumatra was determined from thermal gradients obtained from the extrapolated oil well bottom hole formation temperature and the assumed temperature of 80°F at the surface. The effective thermal conductivity of the whole rock column, by which the gradient is multiplied to get the heat flow was calculated from measurements on 273 specimens of the geologic section and inspection of 92 well logs. For the whole basin the gradient averaged 3.71 ± 1.04°F/ 100 ft (67.6°C/km) the conductivity 4.83 ± 0.31 mcal °C -1 cm -1 sec -1, giving an average heat flow of 3.27 ± 0.93 10-6 cal cm -2 sec -1 which is about twice the world average. The gradient and the heat flow vary inversely with the depth of the wells most of which bottom in the pre-Tertiary basement. This may result from the basement rocks being several times more conductive than the sediments. Mocel calculations on a narrow heat-flow anomaly which rises from a base level of 3.2 HFU to 8.8 HFU suggest that it can be caused by the intrusion less than 55,000 years ago of an igneous plug or laccolith no deeper than 3 km and 2.2 to 4.6 km wide. Using the gradients from the SEAPEX Geothermal Gradient Map and assuming a conductivity of 5 mcal cm -1 °C -1 sec -1, the heat flow in the North Sumatra basin, the South Sumatra Basin, Sunda Strait and West Java is 2.5 HFU, while in Java east of 110°E longitude it drops to 1.9 HFU. Since subduction off Sumatra dates back at least to the Cretaceous, compression of the Asian plate against the Benioff zone is preventing the opening of a back-arc basin. This does not preclude the possibility of occasional periods of crustal tension corresponding perhaps to episodes of transgression which allow magma to rise into the rocks underlying the basin.

  19. Recent nanoplate creation in the central Lau basin

    NASA Astrophysics Data System (ADS)

    Conder, J. A.

    2010-12-01

    The Lau back-arc basin has been opening in a wedge-like fashion for the past six million years. Extension within the basin occurs along a number of spreading centers, sectioning the basin into a number of microplates [Taylor et al., 1996]. The exact geometry of these microplates remain speculative as a few boundaries of hypothesized interior microplates remain unapparent in detailed mapping of the seafloor. Recent analyses of microseismic activity in the basin further illuminates these boundaries. Here I show microseismicity as recorded by a three-month duration ocean bottom seismograph array delineates a previously undetected nanoplate lying at the junction of the Central (CLSC) and Eastern Lau spreading centers (ELSC). The recorded events are located largely using T-waves, energy traveling in the water column not susceptible to the significant mantle attenuation beneath the basin limiting observation of many of the body waves. Event swarms associated with the northern terminus of the ELSC and the Lau Extensional Transform Zone (LETZ) bounding the nanoplate were recorded during the deployment, suggesting an active and ongoing reorganization of the plate boundaries. The Peggy Ridge (PR) transform acted as a typical strike slip boundary in the past, but now the LETZ is manifesting as an extensional reorganization of the PR strike-slip transform fault coupled with accommodation of the Central Lau nanoplate. Likewise, the northern ELSC has been actively retreating with southward advancement of the CLSC. The eastern boundary of the nanoplate is roughly aligned with this retreat, as seen in the microseismicity and suggested by the limits of rugged seafloor making up the crust of the nanoplate. Seafloor disruption is not observed to the east of this boundary suggesting that this nanoplate is in its first incarnation was likely created contemporaneously with CLSC propagation beginning less than one million years ago. Three plates abut the Central Lau nanoplate (C

  20. Sour gas distribution in the Amudaria Basin, Central Asia

    SciTech Connect

    Marina, D.; Ivlev, A.; Shkutnik, E.

    1995-08-01

    The Amudaria Basin is the main sour-gas bearing region in Central Asia. In this region, sour gases occur in Upper Jurassic carbonate-reservoir rocks as well as in terrigenous rocks of Cretareous age, but the Upper Jurassic sulfate-carbonate complex is the main sour-gas bearing and producing complex. The chemical and isotopic composition of fluids in Upper Jurassic rocks show that sulfate reduction is the main process responsible for sour gas formation in the central part of the basin, where Kimmeridgian-Tithonian evaporites occur. The H{sub 2}S content of gases varies widely (0 to 10 percent by volume), even within similar carbonate traps located close to one another in the same temperature zone. Analyses of sour-gas distribution and composition in fluids in these areas indicate the main factors which control the variation of H{sub 2}S content in Upper Jurassic hydrocarbon pools in the same temperature zones. These factors include (1) the carbonate sediment facies type (shelf, barrier reef, deep water facies), and (2) within the same facies, the characteristics of traps and pools (tight, gentle, structural, phase-type, etc). The most favorable conditions for H{sub 2}S accumulation occur in hydrocarbon pools confined to the barrier reef flat and the parts of the shelf closest to it. The least favorable conditions are in pools confined to local reefs or carbonate build-ups located within the deep-water facies zone. These results are important for the prediction of H{sub 2}S in hydrocarbon pools. In most cases, H{sub 2}S in the Cretaceous complex is epigenetic. With the exception of Central Karakum zone H{sub 2}S distribution in this complex depends on the distribution and composition of Upper Jurassic evaporites.

  1. Floodplain Organic Carbon Storage in the Central Yukon River Basin

    NASA Astrophysics Data System (ADS)

    Lininger, K.; Wohl, E.

    2014-12-01

    Floodplain storage of organic carbon is an important aspect of the global carbon cycle that is not well understood or quantified. Although it is understood that rivers transport organic carbon to the ocean, little is known about the quantity of stored carbon in boreal floodplains and the influence of fluvial processes on this storage. We present results on total organic carbon (TOC) content within the floodplains of two rivers, the Dall River and Preacher Creek, in the central Yukon River Basin in the Yukon Flats National Wildlife Refuge of Alaska. The results indicate that organic carbon storage is influenced by fluvial disturbance and grain size. The Dall River, which contains a large amount of floodplain carbon, is meandering and incised, with well-developed floodplain soils, a greater percentage of relatively old floodplain surfaces and a slower floodplain turnover time, and finer grain sizes. Preacher Creek stores less TOC, transports coarser grain sizes, and has higher rates of avulsion and floodplain turnover time. Within the floodplain of a particular river, large spatial heterogeneity in TOC content also exists as a function of depositional environment and age and vegetation community of the site. In addition, saturated regions of the floodplains, such as abandoned channels and oxbow lakes, contain more TOC compared to drier floodplain environments. Frozen alluvial soils likely contain carbon that could be released into the environment with melting permafrost, and thus quantifying the organic carbon content in the active layer of floodplain soils could provide insight into the characteristics of the permafrost beneath. The hydrology in these regions is changing due to permafrost melt, and floodplain areas usually saturated could be dried out, causing breakdown and outgassing of carbon stored in previously saturated soils. Ongoing work will result in a first-order estimate of active-layer floodplain carbon storage for the central Yukon River Basin.

  2. Lower and middle Guadalupian shelf carbonates, eastern margin of Central Basin platform, Permian basin, west Texas

    SciTech Connect

    Ward, R.F.; Chalcraft, R.G.

    1988-01-01

    Lower and middle Guadalupian shelf carbonates serve as the reservoir for a nearly continuous band of oil fields extending 100 mi along the eastern margin of the Central Basin platform of west Texas. Approximately 5 billion bbl of oil have been produced from stratigraphic-structural traps within the Upper Permian (Gaudalupian Series) dolomites of the San Andrea and Grayburg Formations in Upton, Crane, Ector, Pecos, and Andrews Counties, Texas. The San Andrea and Grayburg Formations are cyclical shallowing-upward carbonate sequences of open shelf through sabkha facies whose depositional strike parallels the eastern margin of the Central Basin platform. Porosity and permeability of reservoir rock are governed by diagenetic processes such as dolomitization, anhydrite porosity occlusion, leaching, silicification, and authigenic clay formation. Self sediments are primarily burrowed wackestones and packstones that locally contain pelletal, skeletal, and ooid grainstones. Typical subtidal shelf sediments are capped by algal-laminated dolomite, nodular anhydritic dolomite, and bedded anhydrite. The fauna is normally sparse and dominated by foraminifera and algae. Less common faunal components include pelecypods, crinoids, sponges, Bryozoa, brachiopods, gastropods, and coral that are associated with the development of small scattered patch reefs. Lowering the sea level during the early Guadalpian initiated basinward progradation of San Andres carbonate facies with hydrocarbon reservoirs best developed in shallow self fusulinid wackestones to packstone and oolitic grainstone. Reservoir dolomites of the Grayburg formation are present east of San Andres fields with optimal reservoir properties occurring near the San Andreas outer shelf margin.

  3. The central and northern Appalachian Basin-a frontier region for coalbed methane development

    USGS Publications Warehouse

    Lyons, P.C.

    1998-01-01

    The Appalachian basin is the world's second largest coalbed-methane (CBM) producing basin. It has nearly 4000 wells with 1996 annual production at 147.8 billion cubic feet (Bcf). Cumulative CBM production is close to 0.9 trillion cubic feet (Tcf). The Black Warrior Basin of Alabama in the southern Appalachian basin (including a very minor amount from the Cahaba coal field) accounts for about 75% of this annual production and about 75% of the wells, and the remainder comes from the central and northern Appalachian basin. The Southwest Virginia coal field accounts for about 95% of the production from the central and northern parts of the Appalachian basin. Production data and trends imply that several of the Appalachian basin states, except for Alabama and Virginia, are in their infancy with respect to CBM development. Total in-place CBM resources in the central and northern Appalachian basin have been variously estimated at 66 to 76 trillion cubic feet (Tcf), of which an estimated 14.55 Tcf (~ 20%) is technically recoverable according to a 1995 U.S. Geological Survey assessment. For comparison in the Black Warrior basin of the 20 Tcf in-place CBM resources, 2.30 Tcf (~ 12%) is technically recoverable. Because close to 0.9 Tcf of CBM has already been produced from the Black Warrior basin and the proved reserves are about 0.8 Tcf for 1996 [Energy Information Administration (EIA), 1997]. U.S. Crude Oil, Natural Gas, and Natural Gas Liquids Reserves, 1996 Annual Report. U.S. Department of Energy DOE/EIA-0216(96), 145 pp.], these data imply that the central and northern Appalachian basin could become increasingly important in the Appalachian basin CBM picture as CBM resources are depleted in the southern Appalachian basin (Black Warrior Basin and Cahaba Coal Field). CBM development in the Appalachian states could decrease the eastern U.S.A.'s dependence on coal for electricity. CBM is expected to provide over the next few decades a virtually untapped source of

  4. Evaporation from groundwater discharge playas, Estancia Basin, central New Mexico

    USGS Publications Warehouse

    Menking, Kirsten M.; Anderson, Roger Y.; Brunsell, Nathaniel A.; Allen, Bruce D.; Ellwein, Amy L.; Loveland, Thomas A.; Hostetler, Steven W.

    2000-01-01

    Bowen ratio meteorological stations have been deployed to measure rates of evaporation from groundwater discharge playas and from an adjacent vegetated bench in the Estancia Basin, in central New Mexico. The playas are remnants of late Pleistocene pluvial Lake Estancia and are discharge areas for groundwater originating as precipitation in the adjacent Manzano Mts. They also accumulate water during local precipitation events. Evaporation is calculated from measured values of net radiation, soil heat flux, atmospheric temperature, and relative humidity. Evaporation rates are strongly dependent on the presence or absence of standing water in the playas, with rates increasing more than 600% after individual rainstorms. Evaporation at site E-12, in the southeastern part of the playa Complex, measured 74 cm over a yearlong period from mid-1997 through mid-1998. This value compares favorably to earlier estimates from northern Estancia playas, but is nearly three times greater than evaporation at a similar playa in western Utah. Differences in geographical position, salt crust composition, and physical properties may explain some of the difference in evaporation rates in these two geographic regions.

  5. Flooding and conservation in the Albuquerque bosque

    SciTech Connect

    Crawford, C.S.; Molles, M.C. Jr.; Valett, H.M.

    1995-12-31

    Interest in the conservation of the Middle Rio Grande bosque has grown rapidly in the last decade. During that period, private organizations as well as governmental agencies have sharpened their focus on the issue, and in doing so have contributed to the development of a bosque biological management plan for the river reach between Cochiti Dam and Elephant Butte Reservoir. This increased regional attention reflects a growing national and international concern about human impacts on fluvial processes in large floodplain rivers. Because they impound large amounts of a river`s discharge and interfere with its natural flooding regime, dams can seriously disrupt the relationship between river basin hydrology and riparian zone functioning. In western North America, this interference reduces cottonwood germination and survival and, as will be discussed, negatively affects key ecological processes in riparian communities. In this paper the authors first review how the decoupling of basin hydrology from riparian forest processes has begun to affect the integrity of the Middle Rio Grande bosque ecosystem. Then they propose an alternative management scheme, with emphasis on the Albuquerque bosque, that centers on restoring its ecosystem functioning.

  6. Post-Variscan basin evolution in the central Pyrenees: Insights from the Stephanian-Permian Anayet Basin

    NASA Astrophysics Data System (ADS)

    Rodríguez-Méndez, Lidia; Cuevas, Julia; Tubía, José María

    2016-03-01

    The Anayet Basin, in the central Pyrenees, records a Stephanian-Permian continental succession including three Permian volcanic episodes. The absolute chronology of these rocks has allowed us to better constrain the early post-Variscan evolution of the Pyrenees. The transtensional regime responsible for the formation of the pull-apart Anayet Basin began at least in Stephanian times, the age of the first post-Variscan deposits in the area, and lasted until Late Permian. During Middle Eocene times, the Alpine Orogeny inverted the Anayet Basin and led to the formation of south-vergent chevron folds and axial plane penetrative cleavage.

  7. Hydrocarbon generation and brine migration in the central Appalachian basin

    SciTech Connect

    Evans, M.A. )

    1991-08-01

    Fluid inclusions in mineralized natural fractures from six Devonian shale cores were used to document hydrocarbon generation and brine migration in the central Appalachian basin. The sequence of formation of four regional fracture sets containing the inclusions was used to constrain the relative timing of fluid evolution. The earliest formed fluid inclusions are single-phase liquid inclusions containing a complex mixture of methane, ethane, higher hydrocarbons, and nitrogen. These inclusions formed during burial of the Devonian shales and early hydrocarbon generation in the oil window. As burial proceeded to a maximum and hydrocarbon generation entered the gas phase, later formed fluid inclusions record the presence of a more methane-rich fluid with minor ethane and nitrogen. Either during maximum burial or early uplift of the Devonian shale section, regional stress relaxation was accompanied by regional brine migration. Fluid inclusions record the influx of a methane-saturated, sodium chloride-rich brine and subsequent mixing with a presumably in situ-calcium-rich brine and subsequent mixing with a presumably in-situ calcium-rich brine. The migration pathway is presumed to be the Devonian shale detachment zone and underlying Devonian Oriskany Sandstone. This migration may be related to the fluids forming Mississippi Valley-type ore deposits. Present-day brine compositions reflect this ancient mixing. Brines from deep Cambrian through Silurian rocks are more calcium-chloride rich than brines from shallower Devonian and younger rocks. The sodium chloride-rich brines from Upper Devonian through Pennsylvanian rocks become more dilute as a result of mixing with meteoric water.

  8. HYDROLOGY OF CENTRAL GREAT BASIN MEADOW ECOSYSTEMS – EFFECTS OF STREAM INCISION

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. Our interdisciplinary group has investigated 1) the interrelationships of geomorphology, hydrology, and vegetation; and 2) ...

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

    USGS Publications Warehouse

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

    2013-01-01

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

  10. Miocene transgression in the central and eastern parts of the Sivas Basin (Central Anatolia, Turkey) and the Cenozoic palaeogeographical evolution

    NASA Astrophysics Data System (ADS)

    Poisson, André; Vrielynck, Bruno; Wernli, Roland; Negri, Alessandra; Bassetti, Maria-Angela; Büyükmeriç, Yesim; Özer, Sacit; Guillou, Hervé; Kavak, Kaan S.; Temiz, Haluk; Orszag-Sperber, Fabienne

    2016-01-01

    We present here a reappraisal of the tectonic setting, stratigraphy and palaeogeography of the central part of the Sivas Basin from Palaeocene to late Miocene. The Sivas Basin is located in the collision zone between the Pontides (southern Eurasia) and Anatolia (a continental block rifted from Gondwana). The basin overlies ophiolites that were obducted onto Anatolia from Tethys to the north. The Central Anatolian Crystalline Complex (CACC) experienced similar ophiolite obduction during Campanian time, followed by exhumation and thrusting onto previously emplaced units during Maastrichtian time. To the east, crustal extension related to exhumation of the CACC created grabens during the early Tertiary, including the Sivas Basin. The Sivas Basin underwent several tectonic events during Paleogene-Neogene. The basin fill varies, with several sub-basins, each being characterised by a distinctive sequence, especially during Oligocene and Miocene. Evaporite deposition in the central part of the basin during early Oligocene was followed by mid-late Oligocene fluvio-lacustrine deposition. The weight of overlying fluvial sediments triggered salt tectonics and salt diapir formation. Lacustrine layers that are interbedded within the fluviatile sediments have locally yielded charophytes of late Oligocene age. Emergent areas including the pre-existing Sivas Basin and neighbouring areas were then flooded from the east by a shallow sea, giving rise to a range of open-marine sub-basins, coralgal reef barriers and subsiding, restricted-marine sub-basins. Utilising new data from foraminifera, molluscs, corals and nannoplankton, the age of the marine transgression is reassessed as Aquitanian. Specifically, age-diagnostic nannoplankton assemblages of classical type occur at the base of the transgressive sequence. However, classical stratigraphic markers have not been found within the planktic foraminiferal assemblages, even in the open-marine settings. In the restricted-marine sediments

  11. Fluid migration in sedimentary basins - a case study from the Central European Basin

    NASA Astrophysics Data System (ADS)

    Duschl, Florian; van den Kerkhof, Alfons; Leiss, Bernd; Sosa, Graciela; Wiegand, Bettina; Vollbrecht, Axel; Sauter, Martin

    2014-05-01

    Core samples from the cap rock of an Upper Permian dolomitic limestone from the Zechstein formation (Stassfurt carbonate sequence, Ca2) in the Central European Basin were studied for a better understanding of the tectonic control on fluid migration during the burial and uplift of CO2-rich gas reservoirs. Petrographical investigations were carried out by means of optical transmission and cathodoluminescence microscopy. A heating-freezing stage was applied for fluid inclusion analysis; gas compositions were measured by Laser-Raman spectroscopy. The study focuses on the quantification of paleo pressures, temperatures and compositions of diagenetic fluids trapped as inclusions in dolomite, anhydrite, calcite, and fluorite, as well as in postdiagenetic fluorite in mineralized fractures. Limestone matrix mainly consists of early diagenetic, euhedral dolomite with few hydrocarbon-bearing inclusions. Offset veins originating from fine-grained inclusion-free anhydrite nodules consist of coarse-grained recrystallized anhydrite containing primary aqueous CaCl2-rich inclusions. Late calcite cement fills remnant pores between the dolomite rhombs and contains H2O-NaCl-CaCl2 fluid inclusions. Subsequently, the dolomitic limestones were affected by pressure solution due to burial, followed by basin inversion (uplift) starting in Upper Cretaceous. Pressure solution generated carbonate rich fluids, which resulted in dolomite and calcite veinlets. Simultaneously, a first clearly zoned and brown coloured generation of fluorite (I) accumulated in nodules together with sulfides and organic matter. This fluorite (I) contains mostly H2O-NaCl-CaCl2 fluid inclusions with relatively high salinity (17.8 wt% NaCl, 8.9 wt% CaCl2). Colourless fluorite (II) is the latest observable (post-) diagenetic mineral phase filling veinlets in dolomitic limestone that crosscut pressure solution features. Fluorite (II) replaces fluorite (I) within the nodules as well. Carbonic inclusions together with CH4

  12. Albuquerque Operations Office, Albuquerque, New Mexico: Technology summary

    SciTech Connect

    Not Available

    1994-08-01

    This document has been prepared by the Department of Energy`s (DOE) Environmental Management (EM) Office of Technology Development (OTD) in order to highlight research, development, demonstration, testing, and evaluation (RDDT&E) activities funded through the Albuquerque Operations Office. Technologies and processes described have the potential to enhance DOE`s cleanup and waste management efforts, as well as improve US industry`s competitiveness in global environmental markets. The information has been assembled from recently produced OTD documents that highlight technology development activities within each of the OTD program elements. These integrated program summaries include: Volatile Organic Compounds in Non-Arid Soils, Volatile Organic Compounds in Arid Soils, Mixed Waste Landfill Integrated Demonstration, Uranium in Soils Integrated Demonstration, Characterization, Monitoring, and Sensor Technology, In Situ Remediation, Buried Waste Integrated Demonstration, Underground Storage Tank, Efficient Separations and Processing, Mixed Waste Integrated Program, Rocky Flats Compliance Program, Pollution Prevention Program, Innovation Investment Area, and Robotics Technology.

  13. Pannonian Basin Province, Central Europe (Province 4808) -Petroleum Geology, Total Petroleum Systems, and Petroleum Resource Assessment

    USGS Publications Warehouse

    Dolton, Gordon L.

    2006-01-01

    This report deals with the Pannonian Basin Province of Central Europe and summarizes the petroleum geology, which was the basis for assessment, and presents results of that assessment. The Pannonian Basin Province consists of a large compound extensional basin of Neogene age overlying Paleogene basins and interior elements of the greater Alpine foldbelt. Within it, six total petroleum systems (TPS) are defined and six assessment units established for estimation of undiscovered oil and gas resources. Other speculative TPSs were identified but not included for quantitative assessment within this study.

  14. Water-quality assessment of the Rio Grande Valley, Colorado, New Mexico, and Texas: Shallow ground-water quality and land use in the Albuquerque Area, Central New Mexico, 1993. National water quality assessment program. Water-resources investigations

    SciTech Connect

    Anderholm, S.K.

    1997-12-31

    This report describes the quality of shallow ground water and the relations between land use and the quality of that shallow ground water in an urban area in and adjacent to Albuquerque, New Mexico. Water samples were collected from 24 shallow wells for analysis of selected common constituents, nutrients, trace elements, radionuclides, volatile organic compounds (VOC`s), and pesticides. The results of the chemical analyses are presented in appendices.

  15. Overview of the central North American basins and their relation to deep curstal structure

    SciTech Connect

    Keller, G.R.; Denison, R.E.

    1984-04-01

    As our knowledge of deep structure of major central North American basins has increased, it has become clear that they have experienced long and complicated tectonic histories. A knowledge of these histories is especially important to efforts to formulate exploration strategies for deeper horizons and frontier areas. Regional geophysical and geologic studies of these basins indicate that Precambrian features have often exerted considerable control on basinal development (e.g., Anadarko basin, Rome trough, Rough Creek graben, Pedregosa basin). A particularly important tectonic event was the Eocambrian continental breakup which extensively rifted the southern margin of North America. Although this rifting event is manifested in various ways, its extent can be estimated by mapping he deep-seated crustal anomalies which probably formed at this time. Although age relations are uncertain in most cases, deep-seated anomalies are associated with the Arkoma basin, Anadarko basin, Illinois basin, Mississippi embayment, and Permian basin. There are many similarities in the development of these basins, but they all can be shown to have unique tectonic histories.

  16. Controls of erosional denudation in the orogen on foreland basin evolution: The Oligocene central Swiss Molasse Basin as an example

    NASA Astrophysics Data System (ADS)

    Schlunegger, Fritz; Jordan, Teresa E.; Klaper, Eva Maria

    1997-10-01

    A high-resolution three-dimensional reconstruction of the 25-m.y.-old central Swiss Molasse Basin reveals two sedimentary domains separated by a ˜5-km-wide flood-plain. The proximal domain of the basin attained a width of 20 km, and its basement is steeply flexed (6°-7° dip). Petrographic data indicate that it was filled by sediment from the Rigi dispersal system derived from the central Alps of eastern Switzerland and by locally sourced bajadas. In contrast, the distal sedimentary domain, located farther north, was gently dipping (<2°) and was filled by the meandering Lac Léman and Honegg dispersal systems. Chronological data reveal that sedimentation in the northern proximal part of the basin started at ˜27 Ma, when sediment supply to the basin started to increase. Deflection of the foreland plate at ˜25 Ma is successfully simulated by flexural modeling of the thrust load and the sediment load. The model reveals that the Lac Léman and Honegg dispersal systems are located on a buried flexural bulge. Furthermore, it shows that burial and suppression of the flexural bulge at ˜27 Ma as well as an increase of the basin wavelength were controlled by the contemporaneous increase in the sediment supply rate of the Rigi system. The model presented suggests that the tectonic subsidence of the Molasse Basin was mainly controlled by tectonic events in the northern part of the orogen, within ˜70 km distance from the tip of the orogenic wedge. Crustal thickening in this part of the orogen is reflected in the proximal Molasse by sedimentary cycles characterized by an increase in the sediment accumulation rates up section and by the presence of locally sourced bajada fans at the top of each cycle. Although south vergent back thrusting along the Insubric Line ˜150 km south of the foreland basin contributed little to flexure, it resulted in an increase of the sediment supply to the foreland basin. This is reflected in the Molasse by coarsening and thickening upward

  17. Seismic response of a deep continental basin including velocity inversion: the Sulmona intramontane basin (Central Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Di Giulio, Giuseppe; de Nardis, Rita; Boncio, Paolo; Milana, Giuliano; Rosatelli, Gianluigi; Stoppa, Francesco; Lavecchia, Giusy

    2016-01-01

    The Sulmona plain (central Italy) is an intramontane basin of the Abruzzi Apennines that is known in the literature for its high seismic hazard. We use extensive measurements of ambient noise to map the fundamental frequency and to detect the presence of geological heterogeneities in the basin. We perform noise measurements along two basin-scale orthogonal transects, in conjunction with 2-D array experiments in specific key areas. The key areas are located in different positions with respect to the basin margins: one at the eastern boundary (fault-controlled basin margin) and one in the deepest part of the basin. We also collect independent data by using active seismic experiments (MASW), down-hole and geological surveys to characterize the near-surface geology of the investigated sites. In detail, the H/V noise spectral ratios and 2-D array techniques indicate a fundamental resonance (f0) in the low-frequency range (0.35-0.4 Hz) in the Sulmona Basin. Additionally, our results highlight the important role that is played by the alluvial fans near the edge-sectors of the basin, which are responsible for a velocity inversion in the uppermost layering of the soil profile. The H/V ratios and the dispersion curves of adjacent measurements strongly vary over a few dozens of meters in the alluvial fan area. Furthermore, we perform 1-D numerical simulations that are based on a linear-equivalent approach to estimate the site response in the key areas, using realistic seismic inputs. Finally, we perform a 2-D simulation that is based on the spectral element method to propagate surface waves in a simple model with an uppermost stiff layer, which is responsible for the velocity inversion. The results from the 2-D modelling agree with the experimental curves, showing deamplified H/V curves and typical shapes of dispersion curves of a not normally dispersive site.

  18. Cryogenian-Ediacaran Carbon Isotope Stratigraphy of the Amadeus Basin, Central Australia

    NASA Astrophysics Data System (ADS)

    Joubert, R. L.; Verdel, C.; Schultz, I.

    2014-12-01

    Deciphering the nature of extreme Neoproterozoic climatic and biogeochemical perturbations hinges on correlating sedimentary sequences within and across different basins. To improve these correlations within central Australia, we have focused on the abundant and laterally extensive glaciogenic and carbonate deposits of the Amadeus Basin. Here, we present new high-resolution carbonate C isotope profiles from Cryogenian-Ediacaran stratigraphic successions (the Areyonga, Aralka, Olympic, and Julie Formations) that are particularly well exposed in the northeastern part of the basin. The data appear to span a duration of >100 Ma, from the end of the older Cryogenian glaciation to the upper Ediacaran. In addition to major isotopic excursions resembling those described from other Neoproterozoic successions, the Amadeus Basin isotopic profiles display consistent fine-scale patterns and lateral trends that allow us to identify diachronous strata and refine the overall stratigraphic and tectonic architecture of the basin.

  19. Early Holocene basinal sediments of the Dakhleh Oasis region, south central Egypt

    NASA Astrophysics Data System (ADS)

    Brookes, Ian A.

    1989-09-01

    Twenty samples of artifactual ostrich eggshell and hearth charcoal, firmly to loosely associated with basinal lacustrine, playa, and sand sheet sediments in the Dakhleh Oasis region of south-central Egypt, yield radiocarbon ages between ca. 8800 and ca. 4700 yr B.P. The sediments record variable sedimentary responses to an early Holocene pluvial interval in this virtually rainless region. Differences of hydrogeology and morphometry among and within basin types complicate paleoclimatic interpretation.

  20. Structural failure and drowning of Johnston Atoll, central Pacific Basin

    NASA Astrophysics Data System (ADS)

    Keating, Barbara H.

    Emery (1956) and Ashmore (1973) described the geology of Johnston Atoll (Northern Line Islands chain) and pointed out the anomalous structure of the atoll. These studies led Ashmore )1973) to suggest that the atoll itself is tilted. Johnston Atoll appears to be an example of a seamount that is undergoing a transition from an atoll to a drowned seamount (guyot). Submersible studies of the shallow carbonate bank demonstrate that the carbonate bank displays important karstic features. Recent side-scan sonar studies of the southern flank of this seamount provide evidence that the southern flank of the seamount has undergone substantial mass-wasting. We hypothesize that the mass-wasting of the seamount has loaded the seafloor surrounding Johnston Island unevenly. The southeast Johnston Basin lies 700 m shallower than the southwest Johnston Basin. The loading of the southeast Johnston Basin has resulted in differential subsidence of the sea floor surrounding the seamount which has resulted in the tilting of the seamount (0.016°) and is responsible for the drowning of much of the reef. It is suggested that local structural failure, preferential erosion and drainage, and differential subsidence of seamounts can cause drowning of reefs which may lead to the formation of guyots.

  1. Comparison of Tarim and central Asian FSU basins, II: Differences in hydrocarbon systems and possible explanations

    SciTech Connect

    Shangyou, N.; Heubeck, C.

    1996-12-31

    If the Tertiary crustal shortening and indentation in the Pamirs is restored palinspastically, it would be evident that the Central Asian basins in the FSU (including Amu Darya, Tajik, Fergana, and Syr Darya) in the west and the Tarim basin in the cast probably shared many similarities in their geological history after becoming part of the Eurasia continent in the Late Paleozoic. For example, both areas contain significant amounts of coal-bearing Jurassic sequences, and a marine connection no doubt existed between the two during the maximum marine transgression period of Late Cretaceous and Early Tertiary. A direct comparison is more difficult for the Paleozoic sequences because in the Central Asia basins, they are either buried too deeply or highly metamorphosed in the outcrops. It is interesting to note that these basins exhibit vast differences in the age and type of source and reservoir rocks. For the Tarim basin, most of the source rocks are Paleozoic (Ordovician and Carboniferous) and marine in nature, whereas in the Central Asian basins, the dominant source rocks are Jurassic and younger and include both marine and non-marine sequences. Similarly for the reservoir rocks, most of the hydrocarbons found in the Tarim basin is from the Paleozoic, (such as Devonian and Carboniferous clastics/carbonates), whereas in Amu Darya and Fergana basins, the reservoir rocks are dominated by Jurassic carbonates and Paleogene clastics respectively. This presentation will highlight these differences and address the probable causes mainly from the view points of tectonics and paleogeography. We conclude that the dominant effect is the Early Tertiary India-Asia collision, which caused significant differences in the distribution and thickness of the post-collisional clastic sediments, which in turn resulted in different maturation and migration history.

  2. Comparison of Tarim and central Asian FSU basins, II: Differences in hydrocarbon systems and possible explanations

    SciTech Connect

    Shangyou, N.; Heubeck, C. )

    1996-01-01

    If the Tertiary crustal shortening and indentation in the Pamirs is restored palinspastically, it would be evident that the Central Asian basins in the FSU (including Amu Darya, Tajik, Fergana, and Syr Darya) in the west and the Tarim basin in the cast probably shared many similarities in their geological history after becoming part of the Eurasia continent in the Late Paleozoic. For example, both areas contain significant amounts of coal-bearing Jurassic sequences, and a marine connection no doubt existed between the two during the maximum marine transgression period of Late Cretaceous and Early Tertiary. A direct comparison is more difficult for the Paleozoic sequences because in the Central Asia basins, they are either buried too deeply or highly metamorphosed in the outcrops. It is interesting to note that these basins exhibit vast differences in the age and type of source and reservoir rocks. For the Tarim basin, most of the source rocks are Paleozoic (Ordovician and Carboniferous) and marine in nature, whereas in the Central Asian basins, the dominant source rocks are Jurassic and younger and include both marine and non-marine sequences. Similarly for the reservoir rocks, most of the hydrocarbons found in the Tarim basin is from the Paleozoic, (such as Devonian and Carboniferous clastics/carbonates), whereas in Amu Darya and Fergana basins, the reservoir rocks are dominated by Jurassic carbonates and Paleogene clastics respectively. This presentation will highlight these differences and address the probable causes mainly from the view points of tectonics and paleogeography. We conclude that the dominant effect is the Early Tertiary India-Asia collision, which caused significant differences in the distribution and thickness of the post-collisional clastic sediments, which in turn resulted in different maturation and migration history.

  3. Tectonics and sedimentary evolution of the Sandino forearc basin off Nicaragua, Central America

    NASA Astrophysics Data System (ADS)

    Costa Pisani, P.; Silver, E.; McIntosh, K.; Ahmed, I.; Ranero, C. R.; Taylor, B.

    2003-04-01

    The Sandino basin is the Nicaragua sector of the Central American forearc, where the Cocos plate subducts beneath the Middle America trench. Recently, Ranero et al. have interpreted a seismic section across the margin and proposed a history of formation of the forearc which is constrained by industry drilling in the basin. They suggested a late Cretaceous to Paleocene accretion event, followed by later subduction erosion processes. The margin wedge consists of the ophiolitic Nicoya complex. The seismic units, unconformities and tectonic features record a rich history of both local and regional vertical movements occurring since the Middle Eocene, which are linked to the evolution of the Pacific convergent margin. During June, 2000, 2800 kms of multichannel seismic reflection data were collected on the R/V Ewing off Nicaragua. Analysis of the 240 channels dataset indicates rapid changes along strike in the Sandino basin. The basin is relatively thin in the southern part, thinning quite rapidly southward against the Nicoya complex of the Santa Elena peninsula of Costa Rica. The forearc sediments thickness approaches and locally exceeds 10 kms in the central and northern parts of the Sandino basin. The oldest units (Upper Cretaceous-Middle Eocene) are very thick off northern Nicaragua, with relatively thin middle to late Cenozoic deposits. However, off central Nicaragua the latter units (Middle-Upper Miocene) attain great thicknesses and the older units appear to thin. This pattern suggests a history of successive deepening of the basin from north to south, after the convergent system evolved from accretion to subduction erosion processes. Present efforts are devoted to quantifying this change in development and using it to understand the dynamics of forearc basin evolution offshore of Central America.

  4. Ordovician carbonate buildups: Potential gas reservoirs in the Ordos basin, central China

    SciTech Connect

    Huaida Hsu )

    1991-03-01

    The Ordos basin of central China covers an area of about 25,000 km{sup 2}. A series of eastward moving overthrusts developed along its western flank, but most of the basin consists of a stable slope that dips westward less than one degree. The basin contains sediments from Sinian to Middle Ordovician and from the Middle Carboniferous to Cretaceous. Its evolutionary history is similar to that of the Alberta basin. Recently drilled wildcat wells have produced commercial gas flows that are closely associated with Ordovician carbonate buildups and a weathered surface between the Ordovician and Carboniferous. Most of the buildups consist of agal mounds; however, some Middle Ordovician reefs developed in the western portion and along the southern margin of the Ordos basin. More than 200 buildups were delineated using seismic stratigraphic techniques. They can be divided into four distinct types. The growth and distribution of buildups were controlled by sea-level fluctuations. The interpretations made in this study were based on the integration of results from a variety of analyses including vertical profiling, differential interformational velocity analysis, amplitude versus offset comparisons, G-log analysis, seismic modeling techniques, and high-precision gravity surveys. The best gas prospects are the Ordovician carbonate buildups distributed around the basin's central uplift. The delineation of carbonate buildups and the demonstration that they are associated with commercial gas flows open the gate for future gas exploration in this area.

  5. (137)Cs vertical distribution at the deep basins of the North and Central Aegean Sea, Greece.

    PubMed

    Tsabaris, C; Zervakis, V; Kaberi, H; Delfanti, R; Georgopoulos, D; Lampropoulou, M; Kalfas, C A

    2014-06-01

    Large volume seawater samples were collected for the determination of (137)Cs concentration along with depth in the deep basins of North and Central Aegean Sea. The vertical (137)Cs distribution showed maximum concentration at the bottom of the basins, while the minimum values corresponded to the intermediate layer, where Levantine water exists. The surface (137)Cs activity is found to lie between the two limits and is originated from the Black Sea waters. The typical oceanographic advection-diffusion balance model is modified to a diffusion-settling-decay balance model to better understand the vertical distribution and variation of the (137)Cs concentration in the deep basins. In addition, the diffusivity of each basin, as well as the settling speed of particulate (137)Cs is also estimated. The results are compared with theoretical approach as well as with previous data. PMID:24534571

  6. Assessing and addressing the re-eutrophication of Lake Erie: central basin hypoxia

    USGS Publications Warehouse

    Scavia, Donald; Allan, J. David; Arend, Kristin K.; Bartell, Steven; Beletsky, Dmitry; Bosch, Nate S.; Brandt, Stephen B.; Briland, Ruth D.; Daloğlu, Irem; DePinto, Joseph V.; Dolan, David M.; Evans, Mary Anne; Farmer, Troy M.; Goto, Daisuke; Han, Haejin; Höök, Tomas O.; Knight, Roger; Ludsin, Stuart A.; Mason, Doran; Michalak, Anna M.; Richards, R. Peter; Roberts, James J.; Rucinski, Daniel K.; Rutherford, Edward; Schwab, David J.; Sesterhenn, Timothy M.; Zhang, Hongyan; Zhou, Yuntao

    2014-01-01

    Relieving phosphorus loading is a key management tool for controlling Lake Erie eutrophication. During the 1960s and 1970s, increased phosphorus inputs degraded water quality and reduced central basin hypolimnetic oxygen levels which, in turn, eliminated thermal habitat vital to cold-water organisms and contributed to the extirpation of important benthic macroinvertebrate prey species for fishes. In response to load reductions initiated in 1972, Lake Erie responded quickly with reduced water-column phosphorus concentrations, phytoplankton biomass, and bottom-water hypoxia (dissolved oxygen 2) requires cutting total phosphorus loads by 46% from the 2003–2011 average or reducing dissolved reactive phosphorus loads by 78% from the 2005–2011 average. Reductions to these levels are also protective of fish habitat. We provide potential approaches for achieving those new loading targets, and suggest that recent load reduction recommendations focused on western basin cyanobacteria blooms may not be sufficient to reduce central basin hypoxia to 2000 km2.

  7. The isolation of the Pannonian basin (Central Paratethys): New constraints from magnetostratigraphy and biostratigraphy

    NASA Astrophysics Data System (ADS)

    ter Borgh, Marten; Vasiliev, Iuliana; Stoica, Marius; Knežević, Slobodan; Matenco, Liviu; Krijgsman, Wout; Rundić, Ljupko; Cloetingh, Sierd

    2013-04-01

    In this paper we establish when and how the Pannonian basin and associated Central Paratethys basins were isolated from the remainder of the Paratethys, a system of back-arc basins and inland seas that once extended over a large part of Europe. The isolation, which occurred at the beginning of the Late Miocene, is marked by a paleoenvironmental change from marine to fresh water conditions that caused the regional Sarmatian-Pannonian Extinction Event. It also had significant paleogeographical implications for the basin fill and for sedimentary transport across the Carpathian Mountains. The exact age of and cause for the isolation are still subject to debate. Here, we use magnetostratigraphic dating coupled to ostracod and mollusc biostratigraphy to establish the isolation age of the Pannonian basin. We dated the isolation of the Pannonian basin at 11.63 ± 0.04 Ma in a section on the northern flank of the Fru\\vska Gora inselberg (northern Serbia). This age is in line with recent results from the Vienna basin but predates the isolation of the Transylvanian by 0.33 Myr, suggesting that isolation took place in two steps. We conclude that the uplift of the Carpathian Mountains caused the isolation but that eustatic sea level fluctuations may have had a minor influence as well.

  8. AN INTERDISCIPLINARY APPROACH TO RIPARIAN MEADOW CHARACTERIZATION AND PRIORITIZATION, CENTRAL GREAT BASIN

    EPA Science Inventory

    The Great Basin Ecosystem Management Research group has described the hydrological, geophysical, and geomorphic conditions that lead to the formation and maintenance of riparian meadows of central Nevada. Previous work on these systems has focused on understanding a few study mea...

  9. Research watersheds in the Central Mississippi River Basin: challenges and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Central Mississippi River Basin (CMRB) member of ARS’s Long-Term Agro-Ecosystem Research (LTAR) network is operated by the USDA-ARS Cropping Systems and Water Quality Research Unit located in Columbia Missouri. The CMRB is anchored around the Goodwater Creek Experimental Watershed (GCEW), part o...

  10. HYDROLOGIC AND GEOMORPHIC CONTROLS ON RIPARIAN ECOSYSTEMS IN THE GREAT BASIN OF CENTRAL NEVADA

    EPA Science Inventory

    Understanding surface and ground water flow system interactions is key to maintaining and restoring riparian and wet meadow ecosystems, especially in the Great Basin of central Nevada where they support the majority of the region's biodiversity. To better understand these intera...

  11. Assessment of shale-oil resources of the Central Sumatra Basin, Indonesia, 2015

    USGS Publications Warehouse

    Schenk, Christopher J.; Charpentier, Ronald R.; Klett, Timothy R.; Tennyson, Marilyn E.; Mercier, Tracey J.; Brownfield, Michael E.; Pitman, Janet K.; Gaswirth, Stephanie B.; Leathers-Miller, Heidi M.

    2015-01-01

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 459 million barrels of shale oil, 275 billion cubic feet of associated gas, and 23 million barrels of natural gas liquids in the Central Sumatra Basin, Indonesia.

  12. Petroleum geology of rift basins in Niger, Chad, and Central African Republic

    SciTech Connect

    Genik, G.J. )

    1991-08-01

    Ten Cretaceous-Tertiary rift basins in Niger, Chad and the Central African Republic (C.A.R.) are defined and the petroleum geology is overviewed based on proprietary exploration results derived from more than one million km{sup 2} of aeromagnetics, 10,520 line-km of gravity profiles, 49,721 km of reflection seismic, and 50 exploration wells. The data were acquired by Exxon with partners Shell, Chevron, Elf, Conoco, Texaco, and Amax Oil Gas During 1969-1989. In Niger and Chad, the West African rift subsystem includes the extensional basins of Termit, Tefidet, Tenere, Grein/Kafra, N'Djel Edji, and Bongor. These rift basins contain up to 15,000 m of Cretaceous to Cenozoic continental and marine clastics. Key exploration elements are Tertiary and Cretaceous fluvial to tidal sandstone reservoirs, Tertiary and Cretaceous marine to lacustrine shale source rocks and seals, with traps in normal fault blocks and anticlinal closures. There have been six oil discoveries in the Termit basin. In C.A.R., the Central African rift subsystem incorporates the extensional Doba and transtensional Doseo and Salamat basins flanking the Borogop dextral wrench fault. These basins contain up to 7,500 m of chiefly Cretaceous continental clastics. key exploration elements are Lower and Upper Cretaceous fluvial to lacustrine sandstone reservoirs, Lower Cretaceous lacustrine shale source rocks, lacustrine to flood-plain shale and mudstone seals, with traps in mainly faulted anticlinal closures. There have been six oil discoveries in the Doba basin and three in the Doseo basin. The studied petroleum geology in the rifts of Niger, Chad, and C.A.R. indicates that potentially commercial volumes of oil remain to be discovered.

  13. Petroleum geology of rift basins in Niger, Chad, and the Central African Republic

    SciTech Connect

    Genik, G.J. )

    1991-03-01

    Ten Cretaceous-Tertiary rift basins in Niger, Chad, and the Central African Republic (C.A.R.) are defined and the petroleum geology is overviewed. This paper is based on proprietary exploration results derived from more than 1 million km{sup 2} of aeromagnetics, 10,520 line km of gravity profiles, 49,721 km of reflection seismic, and 50 exploration wells. The data were acquired by Exxon with partners Shell, Chevron, Elf, Conoco, Texaco, and Amax Oil Gas, Inc., during the years 1969-1989. In Niger and Chad, the West African rift subsystem includes the extensional basins of Termit, Tefidet, Tenere, Grein/Kafra, N'Djel Edji, and Bongor. These rift basins contain up to 15,000 m of Cretaceous to Cenozoic continental and marine clastics. Key exploration elements are Tertiary and Cretaceous fluvial to tidal sandstone reservoirs, Tertiary and Cretaceous marine to lacustrine shale source rocks, and seals, with traps in normal fault blocks and anticlinal closures. There are six oil discoveries in the Termit basin. In Chad and the C.A.R., the Central African rift subsystem incorporates the extensional Doba and transtensional Doseo and Salamat basins flanking the Borogop dextral wrench fault. These basins contain up to 7,500 m of chiefly Cretaceous continental clastics. Key exploration elements are Lower and Upper Cretaceous fluvial to lacustrine sandstone reservoirs, Lower Cretaceous lacustrine shale source rocks, lacustrine to flood plain shale and mudstone seals, with traps in mainly faulted anticlinal closures. There are six oil discoveries in the Doba basin and three in the Doseo basin. The studied petroleum geology in the rifts of Niger, Chad, and the C.A.R. indicates that potentially commercial volumes of oil remain to be discovered.

  14. 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.

    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.

  15. Structural and Kinematic Analysis of a Transpressional Basin in Central Anatolia: Çiçekdaǧ Basin

    NASA Astrophysics Data System (ADS)

    Tokay, Bülent; Lefebvre, Côme

    2015-04-01

    The Central Anatolian Crystalline Complex (CACC), which lies within Turkish Alpine orogenic belt, incorporates several basins located either within the complex or at and along its boundaries. Many of the basins developed during extension since Late Cretaceous and then evolved with advancing collision of Anatolide-Tauride with Pontides. With regard to deformation and evolution of the region, recent paleomagnetic study from the central Anatolian intrusives defines three blocks with characteristic rotation, pointing out the break-up of the CACC and the formation of two deformation zones between blocks. This study is focused on Çiçekdağ Basin (ÇB) which is located within one of the intensely deformed zones in the CACC. The structural analysis within and around ÇB in support of these models and claims is, however, limited. Thus this present study aims to provide more structural data that bears on the evolution of the Çiçekdağı Basin as well as the CACC, especially during regional contraction taking place at the end of the Eocene. Major structures of the study area fall into six groups: (i) E-W-trending synclines and a burried major reverse fault, suggesting N-S shortening; (ii) approximately NW-SE-trending plunging en-échelon folds, consistent with NE-SW compression; (iii) a NW-SE-trending (130°) left-lateral strike-slip fault; (iv) E-W-trending (260°) normal fault at southern edge of the basin and NW-SE-trending (~150°) normal fault; (v) NE-SW-trending reverse faults (~050°-055°) in the north of and middle of the basin, with hanging wall syncline geometry compatible with NW-SE to N-S compression; (vi) WNW- ESE trending reverse faults implying nearly N-S compression. At this stage, it is not clear to us if all these structures were encountered within the same strain field or they belong to a poly-phase deformation. This will be evaluated and discussed further.

  16. Hydrology and sedimentation of Bixler Run Basin, central Pennsylvania

    USGS Publications Warehouse

    Reed, Lloyd A.

    1976-01-01

    Rainfall, streamflow, stream chemical, and sediment discharge data were collected from Bixler Run near Loysville, Pa., during the period from February 1954 to September 1969 as part of a project to evaluate sediment discharge from an agricultural area in which soil-conservation techniques were being adopted at a moderate rate. The study was conducted by the U.S. Geological Survey in cooperation with the Pennsylvania Department of Environmental Resources, State Conservation Commission. Sediment yields from the basin averaged 64 tons per square mile (22 tonnes per square kilometre) per year, approximately 25 percent less than yields from the surrounding area. The relation between water discharge and suspended-sediment discharge remained constant during the study. Suspended-sediment concentrations in the streamflow were less than 10 milligrams per litre 70 percent of the time. The concentration of chloride ions in the streamflow increased from 1959 to 1969. Ground water maintained flows at the gaging location at a rate of 1.9 cubic feet per second (0.054 cubic metres per second) during the period of data collection.

  17. Basin formation and inversion of the back-arc, Niigata basin, central Japan: New insight from deep seismic profiling

    NASA Astrophysics Data System (ADS)

    Sato, Hiroshi; Abe, Susumu; Kawai, Nobuo; Saito, Hideo; Kato, Naoko; Shiraishi, Kazuya; Ishiyama, Tatsuya; Fukasawa, Hikaru; Inaba, Mitsuru

    2010-05-01

    Associated with the opening of the Japan Sea, rift-basins have been developed along the Japan Sea coast of northern Honshu. The Niigata basin, central Japan, is one of the such basins and filled by thick (< 8 km) Neogene sediments. By subsequent convergence since the Pliocene, an arc-parallel fold-and-thrust-belt has been developed along the Miocene rift-basins. In this belt devastative earthquakes, such as 1964 Niigata (M7.4), 2004 Chuetsu (M6.8) and 2007 Chuetsu-oki (M6.8) earthquakes, occurred by reverse faulting. Due to thick Neogene sediments, relationship between active faults/folds at near the surface and deep-sited seismogenic source faults is poorly understood. To reveal the crustal structure, in particular geometry of source faults, onshore-offshore integrated deep seismic profiling was undertaken along the two seismic lines in 2008 and 2009. The 2009 Aizu-Sado seismic line is a 135-km-long, onshore-offshore seismic line across Niigata basin and Sado island, which is located in the eastern part of Japan Sea. The 2008 Sanjo-Yahiko seismic line (Sato et al., 2009) is located 20 km south of the seismic line and trending parallel to it. The seismic source was air-gun (3020 cu. inch), four vibroseis trucks and explosives (< 200kg). Along the Sado strait, seismic data was acquired using two-ships to make large offset shot gather. Seismic signals were recorded by ocean bottom cables, cable-connected-recording system and offline recorders, forming a maximum 2400 channels receiver array. The basin fill consists of early to middle Miocene volcaniclastic rocks and overlying Neogene sedimentary rocks showing upward coarsening facies deposited under bathyal to fluvial environment. Main features of basin development, such as early Miocene normal faulting, associated with the formation of Japan Sea, and shortening deformation since Pliocene, are well demonstrated on the seismic sections. Particularly, boundary between pre-Tertiary meta-sedimentary rocks and Miocene

  18. Coal resources of selected coal beds and zones in the Northern and Central Appalachian Basin

    USGS Publications Warehouse

    Ruppert, Leslie; Tewalt, Susan; Bragg, Linda

    2002-01-01

    The Appalachian Basin is one of the most important coal-producing regions in the world. Bituminous coal has been mined in the basin for the last three centuries, and the cumulative production is estimated at 34.5 billion short tons. Annual production in 1998 was about 452 million short tons; the basin's production is mostly in the northern (32 percent) and central (63 percent) coal regions. The coal is used primarily within the Eastern United States for electric power generation, but some of it is suitable for metallurgical uses. The U.S. Geological Survey (USGS) is completing a National Coal Resource Assessment of five coal-producing regions of the United States, including the Appalachian Basin. The USGS, in cooperation with the State geological surveys of Kentucky, Maryland, Ohio, Pennsylvania, Virginia, and West Virginia, has completed a digital coal resource assessment of five of the top-producing coal beds and coal zones in the northern and central Appalachian Basin coal regions -- the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay and Pond Creek coal zones, and the Pocahontas No. 3 coal bed. Of the 93 billion short tons of original coal in these units, about 66 billion short tons remain.

  19. Paleomagnetism of the Central Atlantic Magmatic Province in the Algarve basin, Portugal: First insights

    NASA Astrophysics Data System (ADS)

    Font, Eric; Fernandes, Susana; Neres, Marta; Carvallo, Claire; Martins, Línia; Madeira, José; Youbi, Nasrrddine

    2015-11-01

    We present new rock magnetic and paleomagnetic data of the Central Atlantic Magmatic Province (CAMP) lavas cropping out in the Algarve basin (southern Portugal). Our results show that the magnetic mineralogy of the selected samples is primary and dominated by an assemblage of single-domain (SD) to multi-domain (MD) Ti-poor titanomagnetites. All samples carry a characteristic remanent magnetization of normal (positive) magnetic polarity, similarly to other circum-Atlantic CAMP lava sequences. Except for the sites located in the central part of the Algarve basin, site-based mean directions (5 sites, Group A) are comparable to the giant Messejana dyke's directions, suggesting that both lava flows and dyke were emplaced during the same geological interval (~ 200 Ma). However, sites located in the central part of the basin (4 sites; Group B), just east of the São Marcos-Quarteira fault zone, show a systematic discrepancy in the declination values, which is indicative of a significant vertical-axis rotation that we estimated to be ~ 30° clockwise. We suggest that the observed clockwise vertical-axis rotation was produced by a Riedel dextral shear zone of the São Marcos-Quarteira faults acting during the N-S compression that affected the Southern Portuguese margin in the Cenozoic. Our results provide important insights to unravel the complex history of the Algarve basin since the Mesozoic.

  20. Deep reaching fluid-flow in the Central European Basin System

    NASA Astrophysics Data System (ADS)

    Magri, F.; Bayer, U.; Jahnke, C.; Möller, P.; Pekdeger, A.; Tesmer, M.; Voigt, H.

    2003-04-01

    Extensive evidence for rising saline waters has been gathered through three centuries in different regions of the Central European Basin System. The major goal of the project is to understand the physical, geological, hydrogeological framework of fluid occurrence and transport in the NE German sedimentary basin. In sedimentary basins, the dynamics of fluids is driven by hydraulic potential as well as by density differences due to hydrochemical and geothermal variations therefore a well integrated interpretation of these different dataset is fundamental for numerical models. The database will contain geological data from Quarternary to the base of Permian (data from existing deep drillings and wells, available lithological and structural maps), hydrodynamic and thermal data (permeabilities and porosities, hydraulic heads, areas and rates of recharge and discharge in the superficial aquifers, data of the temperature field, thermal conductivities and heat capacities), hydrochemical and geochemical data (chemical analyses of fluids and rocks). The database will be interpreted and integrated in an existing three-dimensional structural model of the basin (Scheck, 1997, Scheck &Bayer, 1999). The state and the processes of fluid movement in the NE German sedimentary basin will be described in order to yield fundamental input data for numerical modelling (hydrogeological, hydrochemical and hydrodynamic-thermal models). Based on the project's results, progress is expected in understanding the interaction of the structural setting, the thermal field and the fluid characteristics within the different layers of the basin. Not at least, the analysis of the mechanism driving the rising saline waters will contribute to a better understanding of the dynamics in the Central European Basin System.

  1. The subsidence evolution of the Fort Worth Basin in north central Texas, U.S.A

    NASA Astrophysics Data System (ADS)

    Al Salem, Ohood Bader

    Although the Fort Worth Basin in north--central Texas has become a major shale--gas production system in recent years, its subsidence history and dynamic relationship to the Ouachita fold--and--thrust belt have not been well understood. Here I study the sedimentation patterns ' model the basin subsidence and thermal maturation histories to understand the evolution of the Fort Worth Basin . Depositional patterns show that the tectonic loading of both the Muenster Arch and the Ouachita fold--and--thrust belt influenced the subsidence of the basin as early as the middle--late Mississippian. Rapid subsidence of the basin initiated in the earliest Pennsylvanian in response to the propagation of the Ouachita fold--and--thrust belt. The rapid subsidence lasted into the Permian based on 2D flexure subsidence and thermal maturation modeling. The Pennsylvanian source rocks in the northeast part of the basin entered the gas maturation window with ˜ 7 km of burial during the late Pennsylvanian--Permian .

  2. Eustatic and tectonic control of sedimentation in the Pennsylvanian strata of the Central Appalachian Basin

    SciTech Connect

    Chesnut, D.R. Jr. . Kentucky Geological Survey)

    1992-01-01

    Analysis of the Breathitt Group of the Central Appalachian Basin reveals three orders of depositional cycles or trends. The Breathitt coarsening-upward trend (20 million years (my)) represents increasing intensity of the Alleghenian Orogeny. The major transgression (MT) cycle (2.5 my) was controlled by an unknown eustatic or tectonic mechanism. The major coal beds and intervening strata make up the coal-clastic cycle (CC cycle) (=Appalachian cyclothem) which has a 0.4 my periodicity. This periodicity supports eustatic control of sedimentation modulated by an orbital periodicity. Extensive coastal peats deposited at lowstand (CC cycle) were preserved as coals, whereas highstand peats were eroded during the subsequent drop in sea level. Autocyclic processes such as delta switching and avulsion occurred within CC cycles. An Early Pennsylvanian unconformity represents uplift and erosion of mid-Carboniferous foreland basin deposits. Alluvial deposits (Breathitt Group) derived from the highlands were transported to the northwest toward the forebulge. During lowstand, the only outlet available to further sediment transport (Lee sandstones) was toward the southwest (Ouachita Trough), along the Black Warrior-Appalachian foreland basins. The Middle Pennsylvanian marks a period of intermittent overfilling of the foreland basin and cresting of the forebulge. Marine transgressions entered through the foreland basins and across saddles in the forebulge. After the Ouachita Trough was destroyed during the late Middle Pennsylvanian, marine transgressions migrated only across saddles in the forebulge. In the Late Pennsylvanian, marine waters entered the basin only across the diminished forebulge north of the Jessamine Dome.

  3. Carbonate aquifer of the Central Roswell Basin: recharge estimation by numerical modeling

    SciTech Connect

    Rehfeldt, K.R.; Gross, G.W.

    1982-02-01

    The flow of ground water in the Roswell, New Mexico, Artesian Basin, has been studied since the early 1900s and varied ideas have been proposed to explain different aspects of the ground water flow system. The purpose of the present study was to delineate the spatial distribution and source, or sources, of recharge to the carbonate aquifer of the central Roswell Basin. A computer model was used to simulate ground water flow in the carbonate aquifer, beneath and west of Roswell and in the Glorieta Sandstone and Yeso Formation west of the carbonate aquifer.

  4. Influence of rift basin geometry on the subsequent postrift sedimentation and basin inversion: The Organyà Basin and the Bóixols thrust sheet (south central Pyrenees)

    NASA Astrophysics Data System (ADS)

    Mencos, Joana; Carrera, Núria; Muñoz, Josep Anton

    2015-07-01

    The extensional period in the Bay of Biscay-Pyrenean domain during the Early Cretaceous influenced subsequent Upper Cretaceous contractional Alpine structures of the Pyrenean orogen. In the Pyrenees, the Lower Cretaceous rift system shows en echelon geometries for different basins, with the Organyà Basin being one of the most important. This basin is located in the southern central Pyrenees, and the inversion of its W-E southern margin has been related to the development of the Bóixols thrust sheet, the northernmost of the south Pyrenean thrust sheets. Detailed interpretation of outcrop and seismic reflection data has revealed the presence of a NNW-SSE trending relay area, which corresponds to the western boundary of the Organyà Basin. The postrift facies belts parallel this boundary. The geometry of the contractional structures shows related variations such as changes in the structural relief and the plunge and the wavelength across this relay area. The synorogenic sediments also show characteristic thickness variations and onlap geometries perpendicular to thrust-transport direction. These evidences highlight the presence of this extensional margin and corroborate its influence in the subsequent stages of the evolution of the area. Seismic, well, and field data have been incorporated into a 3-D structural model in order to better understand the 3-D geometry of the study area.

  5. Jurassic tectonostratigraphic evolution of the Junggar basin, NW China: A record of Mesozoic intraplate deformation in Central Asia

    NASA Astrophysics Data System (ADS)

    Yang, Yong-Tai; Song, Chuan-Chun; He, Sheng

    2015-01-01

    Mesozoic basins in northwest China provide important records for investigating relationships between intraplate deformation in Central Asia and tectonic processes at Asian boundaries. The present study, using well, seismic, outcrop, and thermochronology data in the Junggar Basin and neighboring areas, describes the main features of Jurassic strata in the basin, analyzes the Jurassic evolution of the basin and neighboring mountain belts, and discusses possible mechanisms of Jurassic intraplate deformation in Central Asia. During the Early-Middle Jurassic, episodic uplift of surrounding mountain belts kept the Junggar Basin a contractional closed basin, and alluvial fan, fluvial, delta, and lacustrine depositional environments successively developed from surrounding ranges to the central basin. During the Late Jurassic, the western and central parts of the basin were folded and uplifted, and deposition migrated mainly to the eastern basin. During the latest Jurassic-earliest Cretaceous, pre-Cretaceous strata in the eastern and northeastern Junggar Basin were folded and uplifted, and coarse-grained sediments were transported from surrounding uplifts to the central basin. We suggest that Jurassic episodic deformation events in the Junggar Basin and other areas of Central Asia are related to the Qiangtang collision during the Late Triassic-Early Jurassic, the closure of the western Mongol-Okhotsk Ocean at the Early/Middle Jurassic boundary, a collision of a microcontinent in the Pamir with the southern Asian margin during the late Middle Jurassic-early Late Jurassic, the collision of the Kolyma-Omolon Block with Siberia at the end of the Jurassic, and the subsequent closure of the eastern Mongol-Okhotsk Ocean during the latest Jurassic-earliest Cretaceous.

  6. Geologic Map of the Pueblo of Isleta Tribal Lands and Vicinity, Bernalillo, Torrance, and Valencia Counties, Central New Mexico

    USGS Publications Warehouse

    Maldonado, Florian; Slate, Janet L.; Love, Dave W.; Connell, Sean D.; Cole, James C.; Karlstrom, Karl E.

    2007-01-01

    This 1:50,000-scale map compiles geologic mapping of the Pueblo of Isleta tribal lands and vicinity in the central part of the Albuquerque Basin in central New Mexico. The map synthesizes new geologic mapping and summarizes the stratigraphy, structure, and geomorphology of an area of approximately 2,000 km2 that spans the late Paleogene-Neogene Rio Grande rift south of Albuquerque, N. Mex. The map is part of studies conducted between 1996 and 2001 under the U.S. Geological Survey (USGS) Middle Rio Grande Basin Study by geologists from the USGS, the New Mexico Bureau of Geology and Mineral Resources (NMBGMR), and the University of New Mexico (UNM). This work was conducted in order to investigate the geologic factors that influence ground-water resources of the Middle Rio Grande Basin, and to provide new insights into the complex geologic history of the Rio Grande rift in this region.

  7. The Paleocene stratigraphic records in the Central Netherlands and close surrounding basins: Highlighting the different responses to a late Danian change in stress regime within the Central European Basin System

    NASA Astrophysics Data System (ADS)

    Deckers, J.

    2015-09-01

    Despite their similar structural style of inversion under Late Cretaceous compressional stress, basins in the Central European Basin System showed different kinematic responses to a late Danian change in the European intra-plate stress-field. The Late Cretaceous phase was recognized throughout the Central European Basin System by compressional inversion of the Mesozoic rifts, and the simultaneous formation of marginal troughs. The late Danian change in stress regime resulted in a Middle Paleocene phase which excited longer wavelength of vertical surface movements. In several basins in Central Europe, this Middle Paleocene phase was characterized by domal uplift of the Late Cretaceous inversion zones and their proximal areas, which was interpreted to result from a sudden relaxation of the in-plane tectonic stress (a so-called relaxation inversion). Based on the Paleocene stratigraphic records, this study shows that some basins in the south-western part of the Central European Basin System experienced subsidence of the Late Cretaceous inversion zones during the Middle Paleocene phase, or the complete opposite vertical surface movements of a relaxation inversion. Two possible mechanisms (superposition of relaxation inversions and lithospheric folding during compression) are discussed that could provide an explanation for the opposite late Danian and Selandian vertical surface movements of nearby basins in the Central European Basin System.

  8. Overview of the structural geology and tectonics of the Central Basin Platform, Delaware Basin, and Midland Basin, West Texas and New Mexico

    SciTech Connect

    Hoak, T.; Sundberg, K.; Ortoleva, P.

    1998-12-31

    The structural geology and tectonics of the Permian Basin were investigated using an integrated approach incorporating satellite imagery, aeromagnetics, gravity, seismic, regional subsurface mapping and published literature. The two primary emphases were on: (1) delineating the temporal and spatial evolution of the regional stress state; and (2) calculating the amount of regional shortening or contraction. Secondary objectives included delineation of basement and shallower fault zones, identification of structural style, characterization of fractured zones, analysis of surficial linear features on satellite imagery and their correlation to deeper structures. Gandu Unit, also known as Andector Field at the Ellenburger level and Goldsmith Field at Permian and younger reservoir horizons, is the primary area of interest and lies in the northern part of Ector county. The field trends northwest across the county line into Andrews County. The field(s) are located along an Ellenburger thrust anticline trap on the eastern margin of the Central Basin Platform.

  9. 77 FR 20690 - Environmental Impact Statement: Albuquerque, New Mexico

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-05

    ... TRANSPORTATION Federal Highway Administration Environmental Impact Statement: Albuquerque, New Mexico AGENCY... the Interstate 25 and Paseo del Norte Interchange in Albuquerque, New Mexico. FOR FURTHER INFORMATION CONTACT: Greg Heitmann, Environmental Specialist, Federal Highway Administration, New Mexico...

  10. Recharge sources and hydrogeochemical evolution of groundwater in alluvial basins in arid central Australia

    NASA Astrophysics Data System (ADS)

    Vanderzalm, J. L.; Jeuken, B. M.; Wischusen, J. D. H.; Pavelic, P.; Le Gal La Salle, C.; Knapton, A.; Dillon, P. J.

    2011-01-01

    SummaryIt is necessary to define the role of various sources of recharge in the surficial alluvial aquifer system in arid Alice Springs in central Australia, for future management of water resources in the region. Multiple sources of natural recharge include infiltration from ephemeral stream flow in the Todd River; groundwater throughflow between connected alluvial basins; regional groundwater flow from the underlying Tertiary aquifer; and diffuse recharge. In addition treatment, storage and irrigation reuse of Alice Springs' waste water has resulted in additional recharge of effluent, via infiltration. Water resource management plans for the region include effluent reuse through Soil Aquifer Treatment (SAT) within one of the connected alluvial basins, with the purpose of managing the excess waste water overflows while also supplementing groundwater resources for irrigation and protecting their quality. Hydrogeochemical tracers, chloride and the stable isotopes of water, were used in a three-member mixing model to define and quantify the major recharge sources. The mixing model was not sensitive enough to quantify minor contributions from effluent in groundwater that were identified only by an evaporated isotopic signature. The contribution of the multiple recharge sources varied spatially with proximity to the recharge source; with Todd River, effluent and Town Basin throughflow contributing to the Inner Farm Basin groundwater. The Outer Farm Basin was largely influenced by the Todd River, the Inner Farm Basin throughflow and the older Tertiary aquifer. While Inner Farm groundwater throughflow contains an effluent component, only Outer Farm Basin groundwater near the interface between the two basins clearly illustrated an effluent signature. Aside from this, effluent recharge was not evident in the Outer Farm Basin, indicating that past unmanaged recharge practices will not mask signs of Managed Aquifer Recharge through the Soil Aquifer Treatment (SAT) operation

  11. Age and paleoenvironmental reconstruction of partially remagnetized lacustrine sedimentary rocks (Oligocene Aktoprak basin, central Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Meijers, Maud J. M.; Strauss, Becky E.; Özkaptan, Murat; Feinberg, Joshua M.; Mulch, Andreas; Whitney, Donna L.; Kaymakçı, Nuretdin

    2016-03-01

    The age and paleoenvironmental record of lacustrine deposits in the Aktoprak basin of south-central Turkey provides information about the evolution of topography, including the timing of development of an orographic rain shadow caused by uplift of the mountain ranges fringing the Central Anatolian Plateau. New magnetostratigraphy-based age estimates, in combination with existing biostratigraphic ages, suggest that the partially remagnetized Kurtulmuş Tepe section of the basin is Chattian (Upper Oligocene). The mean carbon and oxygen stable isotope ratios (δ18O= 24.6 ± 2.0 ‰, δ13C= -4.9 ± 1.1‰) are largely constant through the section and indicative of a subtropical, open freshwater lake. These isotopic values are also similar to those of the Chattian Mut basin to the south, on the Mediterranean side of the modern orographic barrier (Tauride Mountains), and indicate absence of an orographic barrier during Late Oligocene basin deposition. Post-depositional partial remagnetization occurred after tilting of the basin sequence and was mineralogically controlled, affecting grey, carbonate-rich rocks (average %CaCO3= 82), whereas interlayered pink carbonate-poor rocks (average %CaCO3= 38) carry a primary, pretilt magnetization. The pink rocks are rich in clay minerals that may have reduced the permeability of these rocks that carry a primary magnetization, concentrating basinal fluid flow in the carbonate-rich grey layers and leading to the removal and reprecipitation of magnetic minerals. The normal and reverse polarities recorded by the remagnetized rocks suggest that remagnetization occurred over a protracted period of time.

  12. Tectono-climatic implications of Eocene Paratethys regression in the Tajik basin of central Asia

    NASA Astrophysics Data System (ADS)

    Carrapa, Barbara; DeCelles, Peter G.; Wang, Xin; Clementz, Mark T.; Mancin, Nicoletta; Stoica, Marius; Kraatz, Brian; Meng, Jin; Abdulov, Sherzod; Chen, Fahu

    2015-08-01

    Plate tectonics and eustatic sea-level changes have fundamental effects on paleoenvironmental conditions and bio-ecological changes. The Paratethys Sea was a large marine seaway that connected the Mediterranean Neotethys Ocean with Central Asia during early Cenozoic time. Withdrawal of the Paratethys from central Asia impacted the distribution and composition of terrestrial faunas in the region and has been largely associated with changes in global sea level and climate such as cooling associated with the Eocene/Oligocene transition (EOT). Whereas the regression has been dated in the Tarim basin (China), the pattern and timing of regression in the Tajik basin, 400 km to the west, remain unresolved, precluding a test of current paleogeographic models. Here we date the Paratethys regression in Tajikistan at ca. 39 million years ago (Ma), which is several million years older than the EOT (at ca. 34 Ma) marking the greenhouse to icehouse climate transition of the Cenozoic. Our data also show a restricted, evaporitic marine environment since the middle-late Eocene and establishment of desert like environments after ca. 39 Ma. The overall stratigraphic record from the Tajik basin and southern Tien Shan points to deposition in a foreland basin setting by ca. 40 Ma in response to active tectonic growth of the Pamir-Tibet Mountains at the same time. Combined with the northwestward younging trend of the regression in the region, the Tajik basin record is consistent with northward growth of the Pamir and suggests significant tectonic control on Paratethys regression and paleoenvironmental changes in Central Asia.

  13. Computers at the Albuquerque Seismological Laboratory

    USGS Publications Warehouse

    Hoffman, J.

    1979-01-01

    The Worldwide Standardized Seismograph Network (WWSSN) is managed by the U.S Geological Survey in Albuquerque, N. Mex. It consists of a global network of seismographs housed in seismic observatories throughout the world. An important recent addition to this network are the Seismic Research Observatories (SRO) which combine a borehole seismometer with a modern digital data recording system. 

  14. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

    NASA Astrophysics Data System (ADS)

    Bahlburg, H.; Breitkreuz, C.

    The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

  15. Basin inversion in central Taiwan and its importance for seismic hazard

    NASA Astrophysics Data System (ADS)

    Camanni, Giovanni; Chen, Chi-Hsuan; Brown, Dennis; Alvarez-Marron, Joaquina; Wu, Yih-Min; Chen, Hsi-An; Huang, Hsin-Hua; Chu, Hao-Tsu; Chen, Mien-Ming; Chang, Chien-Hsin

    2015-04-01

    On March 27th, 2013, a 6.2 ML earthquake occurred at 19 km depth in eastern Nantou, central Taiwan. Over a two-week period it was followed by more than 680 aftershocks that ranged up to 5 ML. Most events occurred below the c. 10 km deep detachment fault predicted for this part of the mountain belt, coinciding with other precisely located hypocenters that indicate that much of the crust in this area is seismically active. Here, we combine geological data with a 3D P-wave velocity model derived from local tomography and earthquake hypocenters to determine a model for the structure of central Taiwan. Much of the surface geology of the area comprises the uplifted Eocene-aged rocks of the Hsuehshan Basin. The 3D P-wave velocity model shows a shallowing of higher velocities across the Hsuehshan Basin and hypocenter data indicate that its western bounding fault is clearly defined by an eastward-dipping band of events that extends to > 20 km depth. The eastern bounding fault is interpreted to coincide at depth with a cluster of events between 20 km and 30 km depth. These data suggest that the pre-existing, rift-related extensional faults of the Hsuehshan Basin are currently being reactivated and the basin is being inverted. Finally, we present hypocenter data from the Nantou sequence that corroborates this interpretation and shows the importance of choosing the correct structural model when assessing seismic risk.

  16. Compression of oceanic lithosphere - An analysis of intraplate deformation in the Central Indian Basin

    NASA Technical Reports Server (NTRS)

    Zuber, Maria T.

    1987-01-01

    The development of intraplate structure in the Central Indian Basin is examined using models in which deformation is due to flexural buckling and the hydrodynamic growth of instabilities. Comparison of the models reveal that in a strong viscous lithosphere, deformation of the layer occurs by flexural folding at a wavelength which corresponds to the flexural buckling theory; in a lithosphere of intermediate strength, the layer deforms by folding characterized by thickening which localizes beneath topographic heights; and in a relatively weak lithosphere, the layer incurs an even greater amount of localized thickening and deforms in the symmetric or pinch-and-swell mode by inverse boudinage. It is noted that the models in which the layer folds either flexurally or with periodic thickening correspond with observed depth distribution of seismicity in the Central Indian Basin and with experimental rock rheological data.

  17. Climate change adaptation in a highly urbanized snowmelt dominated basin in Central Chile

    NASA Astrophysics Data System (ADS)

    Vicuna, S.; Bustos, E.; Merino, P.; Henriquez Dole, L. E.; Jansen, S.; Gil, M.; Ocampo, A.; Poblete, D.; Tosoni, D.; Meza, F. J.; Donoso, G.; Melo, O.

    2015-12-01

    The Maipo river basin holds 40% of Chile's total population and produces almost half of the country's Gross Domestic Product. The basin is located in the semiarid and snowmelt dominated central region of the country and, aside from the typical pressures of growth in developing country basins, the Maipo river basin faces climate change impacts associated with a reduction in total runoff and changes in its seasonality. Surface water is the main water source for human settlements, natural ecosystems, and economic activities including agriculture, mining and hydropower production. In 2012 a research project, called MAPA (Maipo Plan de Adaptacion), began with the objective of articulating a climate variability and climate change adaptation plan for the Maipo river basin. The project engaged at the beginning a group of relevant water and land use stakeholders which allowed for a good representation of critical aspects of an adaptation plan such as the definition of objectives and performance indicators, future land use scenarios, modeling of the different components of the system and design of adaptation strategies. The presentation will highlight the main results of the research project with a special focus on the upper catchments of the basin. These results include the assessment of impacts associated with future climate and land use scenarios on key components of the hydrologic cycle including snowmelt and glacier contribution to runoff and subsequent impacts on water availability for the operation of hydropower facilities, satisfaction of instream (recreation and aquatic ecosystem) uses and provision of water for the city of Santiago (7 million people) and to irrigate more than 100,000 hectares of high value crops. The integrative approach followed in this project including different perspectives on the use of water in the basin provides a good opportunity to test the varying degree of impacts that could be associated with a given future scenario and also understand

  18. 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

  19. Assessment of undiscovered oil and gas resources of the Chad Basin Province, North-Central Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Schenk, Christopher J.; Charpentier, Ronald R.; Klett, Timothy R.; Cook, Troy A.; Pollastro, Richard M.; Tennyson, Marilyn E.

    2010-01-01

    The Chad Basin Province located in north-central Africa recently was assessed for undiscovered, technically recoverable oil, natural gas, and natural gas liquids resources as part of the U.S. Geological Survey's (USGS) World Oil and Gas Assessment. Using a geology-based assessment methodology, the USGS estimated mean volumes of 2.32 billion barrels of oil, 14.65 trillion cubic feet of natural gas, and 391 million barrels of natural gas liquids.

  20. 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

  1. 10Be variation in surficial sediments of the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Nagender Nath, B.; Aldahan, A.; Possnert, G.; Selvaraj, K.; Mascarenhas-Pereira, M. B. L.; Chen, C. T. A.

    2007-06-01

    Distribution of 10Be in systematically collected (degree × degree interval at 10 to 16 °S; 73.5 to 76.5 °E) surficial siliceous ooze, siliceous clay and pelagic clay sediments (top 2 cm) from the abyssal Central Indian Basin and the Andaman Sea is used to evaluate sources and to decipher the transport pathways of sediment particles, demarcate sediment depocenters and erosional areas. While 10Be concentrations display a wide variation (0.12-5.56 × 109 atoms g-1) with an average of 3.58 × 109 atoms g-1 in the Central Indian Basin, the values in the Andaman Sea are uniform with an average of 1.49 × 109 atoms g-1. The 10Be/9Be values in the Central Indian Basin sediments range between 0.06 and 2.99 × 10-8 atoms atoms-1 and average to ∼1.56 × 10-8 atoms atoms-1. Correlation of 10Be data with some selected major (Al, Mn, Ti) and trace (Rb and Ba) elements suggest that large part of the isotope has been supplied through direct atmospheric fallout from the water column and minor part from lithogenic detrital flux. Significantly lower 10Be accumulation rates in the Central Indian Basin and an order of magnitude higher in the Andaman Sea sediments compared to the estimated global average production rates indicate removal of the isotopes at the continental margins. Bottom topography seems to exert control on local 10Be variation, where sediments deposited in valleys or topographic depressions contain higher 10Be concentrations in contrast to the probably erosion-dominated areas at the slopes and troughs.

  2. 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.

  3. A tectonically controlled basin-fill within the Valle del Cauca, West-Central Colombia

    SciTech Connect

    Rine, J.M.; Keith, J.F. Jr.; Alfonso, C.A.; Ballesteros, I.; Laverde, F.; Sacks, P.E.; Secor, D.T. Jr. ); Perez, V.E.; Bernal, I.; Cordoba, F.; Numpaque, L.E. )

    1993-02-01

    Tertiary strata of the Valle del Cauca reflect a forearc/foreland basin tectonic history spanning a period from pre-uplift of the Cordillera Central to initiation of uplift of the Cordillera Occidental. Stratigraphy of the Valle del Cauca begins with Jurassic-Cretaceous rocks of exotic and/or volcanic provenance and of oceanic origin. Unconformably overlying these are Eocene to Oligocene basal quartz-rich sandstones, shallow marine algal limestones, and fine-grained fluvial/deltaic mudstones and sandstones with coalbeds. These Eocene to Oligocene deposits represent a period of low tectonic activity. During late Oligocene to early Miocene, increased tectonic activity produced conglomeratic sediments which were transported from east to west, apparently derived from uplift of the Cordillera Central, and deposited within a fluvial to deltaic setting. East-west shortening of the Valle del Cauca basin folded the Eocene to early Miocene units, and additional uplift of the Cordillera Central during the later Miocene resulted in syn-tectonic deposition of alluvial fans. After additional fold and thrust deformation of the total Eocene-Miocene basin-fill, tectonic activity abated and Pliocene-Quaternary alluvial and lacustrine strata were deposited. Within the framework of this depositional and tectonic history of the Valle del Cauca, hydrocarbon exploration strategies can be formulated and evaluated.

  4. Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

    SciTech Connect

    Milton, J.D. ); Edwards, E.B. ); Heck, R.G. )

    1996-01-01

    Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lying semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.

  5. Geology of the undeveloped oil and gas fields of Central Offshore Santa Maria Basin, California

    SciTech Connect

    Milton, J.D.; Edwards, E.B.; Heck, R.G.

    1996-12-31

    Two prominent subsurface structural features of the Central Offshore Santa Maria Basin are the Hosgri fault system and the associated anticlinal fold trend. Exploratory drilling and 3D seismic mapping have delineated a series of oil and gas fields along this trend which underlie four federal units and one non-unitized lease. The units are named after local geography and are called the Lion Rock, Point Sal, Purisima Point and Santa Maria Units. The individual lease, OCS P-0409, overlies the San Miguel field. The Hosgri fault system trends northwest-southeast and effectively forms the eastern boundary of the oil and gas province. Lying semi-parallel with the fault are several anticlinal culminations which have trapped large volumes of oil and gas in the fractured Montery Formation. The Monterey is both source and reservoir rock, averaging 300 meters n thickness throughout the Central Basin. Development of the Monterey Formation as a reservoir rock was through diagensis and tectonism with resulting porosities-from 15 to 20% and permeability up to one Darcy. These parameters coupled with a high geothermal gradient facilitate the inflow rates of the viscous Monterey oil. Some 24 exploration and delineation wells have been drilled in this area and tested at rates ranging from a few hundred to several thousand barrels per day. Estimated oil reserves in the Central Offshore Santa Maria Basin total approximately 1 billion barrels.

  6. Latest Cretaceous-Paleogene basin development and resultant sedimentation patterns in the thrust belt and broken foreland of central Utah

    SciTech Connect

    Lawton, T.F. ); Franczyk, K.J.; Pitman, J.K. )

    1990-05-01

    Latest Cretaceous tectonism in central and east-central Utah formed several intermontane basins both atop thrust sheets and between the thrust front and basement-involved uplifts in the former foreland basin. The upper Campanian Castlegate Sandstone and its inferred western equivalents were the last strata deposited prior to segmentation of the foreland basin. Thereafter, eastward transport of the thrust allochthon uplifted the most proximal part of the Castlegate depositional wedge. West of the thrust front, small intermontane basins formed on the allochthon. Sediment was transported into these basins from both eastern and western sources. In each basin, facies grade from basin-margin conglomeratic alluvial fan deposits to basin-interior flood-plain and lacustrine deposits within a few kilometers. These intermontane basins existed from latest Campanian through the late Paleocene, and may have been transported a short distance eastward as they formed. East of the thrust front in the latest Campanian and contemporaneous with basin formation on the allochthon, a northward-northeastward-flowing big river system transported sediment into the foreland basin from feldspar-rich source areas southwest of the study area. Subsequently, major movement of the San Rafael uplift in the very late Campanian or early Maastrichtian gave rise to an intermontane basin between the thrust front and the San Rafael uplift. Northwestward-flowing, pebble-bearing braided rivers deposited the oldest sediments in this basin prior to an influx from the south and southwest of sediment that formed a thick Maastrichtian clastic sequence. In contrast to deposition in basins on the allochthon, deposition east of the thrust front in the Paleocene was intermittent and restricted to rapidly shifting centers of basin subsidence.

  7. Salar de Atacama basin: A record of compressional tectonics in the central Andes since the mid-Cretaceous

    NASA Astrophysics Data System (ADS)

    Arriagada, Cesar; Cobbold, Peter R.; Roperch, Pierrick

    2006-02-01

    The Salar de Atacama basin lies in the inner fore arc of northern Chile. Topographically and structurally, it is a first-order feature of the central Andes. The sedimentary fill of the basin constrains the timing and extent of crustal deformation since the mid-Cretaceous. We have studied good exposures along the western edge of the basin and have correlated them with seismic reflection sections and data from an exploration well. Throughout most of its history, the basin developed in a foreland setting, during periods of thin-skinned and thick-skinned thrusting. Growth strata provide evidence for coeval sedimentation and thrust motions during mid-Cretaceous, Paleogene, and Neogene times. Pre-Neogene deformation was significant in the basin and in surounding areas of the early central Andes. Models that attempt to explain the current thickness of the central Andes should consider Late Cretaceous and Paleogene shortening, as well as the more obvious Neogene and Quaternary shortening.

  8. The Albuquerque Seismological Laboratory Data Quality Analyzer

    NASA Astrophysics Data System (ADS)

    Ringler, A. T.; Hagerty, M.; Holland, J.; Gee, L. S.; Wilson, D.

    2013-12-01

    The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several efforts underway to improve data quality at its stations. The Data Quality Analyzer (DQA) is one such development. The DQA is designed to characterize station data quality in a quantitative and automated manner. Station quality is based on the evaluation of various metrics, such as timing quality, noise levels, sensor coherence, and so on. These metrics are aggregated into a measurable grade for each station. The DQA consists of a website, a metric calculator (Seedscan), and a PostgreSQL database. The website allows the user to make requests for various time periods, review specific networks and stations, adjust weighting of the station's grade, and plot metrics as a function of time. The website dynamically loads all station data from a PostgreSQL database. The database is central to the application; it acts as a hub where metric values and limited station descriptions are stored. Data is stored at the level of one sensor's channel per day. The database is populated by Seedscan. Seedscan reads and processes miniSEED data, to generate metric values. Seedscan, written in Java, compares hashes of metadata and data to detect changes and perform subsequent recalculations. This ensures that the metric values are up to date and accurate. Seedscan can be run in a scheduled task or on demand by way of a config file. It will compute metrics specified in its configuration file. While many metrics are currently in development, some are completed and being actively used. These include: availability, timing quality, gap count, deviation from the New Low Noise Model, deviation from a station's noise baseline, inter-sensor coherence, and data-synthetic fits. In all, 20 metrics are planned, but any number could be added. ASL is actively using the DQA on a daily basis for station diagnostics and evaluation. As Seedscan is scheduled to run every night, data quality analysts are able to then use the

  9. DISTRIBUTION, ABUNDANCE AND ENTRAINMENT STUDIES OF LARVAL FISHES IN THE WESTERN AND CENTRAL BASINS OF LAKE ERIE

    EPA Science Inventory

    To assess the impact of entrainment of larval fishes at steam generating electrical power plants, samples were collected in Lake Erie. In 1975, 1976 and 1977 the Western Basin was sampled and in 1978 the sampling was concentrated in the Central Basin. The 1975, 1976 sampling perm...

  10. The nitrogen budget for different forest types in the central Congo Basin

    NASA Astrophysics Data System (ADS)

    Bauters, Marijn; Verbeeck, Hans; Cizungu, Landry; Boeckx, Pascal

    2016-04-01

    Characterization of fundamental processes in different forest types is vital to understand the interaction of forests with their changing environment. Recent data analyses, as well as modeling activities have shown that the CO2 uptake by terrestrial ecosystems strongly depends on site fertility, i.e. nutrient availability. Accurate projections of future net forest growth and terrestrial CO2 uptake thus necessitate an improved understanding on nutrient cycles and how these are coupled to the carbon (C) cycle in forests. This holds especially for tropical forests, since they represent about 40-50% of the total carbon that is stored in terrestrial vegetation, with the Amazon basin and the Congo basin being the largest two contiguous blocks. However, due to political instability and reduced accessibility in the central Africa region, there is a strong bias in scientific research towards the Amazon basin. Consequently, central African forests are poorly characterized and their role in global change interactions shows distinct knowledge gaps, which is important bottleneck for all efforts to further optimize Earth system models explicitly including this region. Research in the Congo Basin region should combine assessments of both carbon stocks and the underlying nutrient cycles which directly impact the forest productivity. We set up a monitoring network for carbon stocks and nitrogen fluxes in four different forest types in the Congo Basin, which is now operative. With the preliminary data, we can get a glimpse of the differences in nitrogen budget and biogeochemistry of African mixed lowland rainforest, monodominant lowland forest, mixed montane forest and eucalypt plantations.

  11. Salt distribution in the Norwegian-Danish Basin, Central North Sea

    NASA Astrophysics Data System (ADS)

    Sassier, Caroline; Jarsve, Erlend; Heeremans, Michel; Mansour Abdelmalak, Mohamed; Faleide, Jan Inge; Helge Gabrielsen, Roy

    2014-05-01

    Salt tectonics have extensively been studied in most parts of the Central North Sea. However, few studies have been done in the Norwegian side of the Norwegian-Danish Basin. In this contribution, we report a new regional analysis of the salt patterns across the offshore Norwegian-Danish Basin. We have mapped the regional distribution of salt structures in the Norwegian-Danish Basin using both old and recent 2D seismic reflection profiles tied to wells. The salt-thickness map shows three distinct salt structures patterns: (1) NW-SE trending salt walls in the northern part of the basin; the spacing between the walls vary between 7 to 12 km; (2) a dense and irregular distribution of salt diapirs in the southern part of the studied area; (3) an irregular pattern of sparse but big salt diapirs in the eastern part of the basin. This domain is characterized by numerous turtle structures associated with salt diapirs. Reflection seismic cross-sections show that most salt structures only pierce the Triassic sedimentary strata whereas only few salt structures reach the seabed. Rotated fault blocks indicate a gliding vergence towards the South in the eastern part of the basin and towards the SE in the western side of the Norwegian-Danish Basin. No mature or compressive salt structures, except some squeezed salt diapirs, are observed in the topographic lows of the basin. The initiation of salt tectonics started during the early Middle Triassic in the entire basin; salt tectonics reactivations were recorded during the Middle Jurassic, Paleogene, and prior to the Quaternary but are not homogeneous across the basin. Salt movements inferred from our study are in good agreement with previous studies. The trend of salt walls (domain 1) indicates a NE-SW extension which is not compatible with N-S trending pre-salt faults. Instead, the strong Triassic subsidence towards the SW has most likely controlled the formation of the salt walls. The salt was initially thicker in domain 2 that

  12. Hydrologic response of a high altitude glacierized basin in the central Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Binquan; Yu, Zhongbo; Liang, Zhongmin; Acharya, Kumud

    2014-07-01

    Hydrologic cycles of most high altitude glacierized watersheds in the Tibetan Plateau are not closely monitored due to their inaccessibility. Understanding the hydrologic cycle in such a basin may provide insight into the role climate plays on changes in glacier mass. Thus, hydrologic simulations with a physical perspective in the Tibetan glacierized watershed are of great significance. A high altitude glacierized basin in the central Tibetan Plateau, Qugaqie basin, was investigated with an energy-balance based glacier-melt model and the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. With these two models, glacier mass balance was estimated and basin runoff from glaciers was simulated at a daily time step. Results from the simulation period (October 1, 2006-September 30, 2011) demonstrated that the glaciers experienced a large negative surface mass balance with the cumulative value of - 300 cm w.e.. In other words, up to 13.93 × 106 m3 water volume was melting out from the glaciers during these five years. In the 2007/08 year, however, the glaciers experienced a surplus mass balance because of the low air temperature and increased precipitation in the summer season. Infiltration, evapotranspiration (ET), and overland flow were also calculated using the GSSHA model. Results showed that precipitation, the main water source, contributed roughly 95% to the total mass gain of the annual water balance in the Qugaqie basin during the study period, while the glacial runoff (snow/ice melting) contributed 5% water balance. In the water loss, 17% of annual water volume was consumed by the ET process. As a result, the remaining water volume (83%) converted to the basin river flow to the Lake Nam Co. In the summertime, the glacial runoff accounted for 15% of the total basin runoff volume, while this contribution increased in the upstream portion to 46% due to a large percentage of glacierized area. The analysis showed that the glacial runoff contributions to the

  13. Gafsa trough of central Tunisia: Basin evolution and maturation of hydrocarbons

    SciTech Connect

    Schamel, S.; Reed, J.K. ); Traut, M. ); Hassine, B.K. )

    1991-03-01

    The Gafsa trough of onshore central Tunisia is one of the more interesting and underexplored features of North Africa. It is a 5-12 km deep, east-west-trending depression along the inner edge of the Tunisian-Libyan shelf margin. The basin has had a long and virtually uninterrupted history of subsidence from the late Paleozoic into the early Cenozoic. Subsidence began in the late Carboniferous, soon after the close of the Hercynian orogeny, and resulted in deposition of a 3000+ m succession of Permo-Carboniferous carbonates and shale that pinches out southward onto the Saharan Flexure. The tectonic setting for this earliest phase of subsidence is not clear. The main episode of subsidence, which began in the Middle Triassic, continued through the Jurassic as left-lateral, transtensional rifting along the South Saharan and Maghrebian Shear zones. A set of organic maturation maps for onshore central Tunisia depicts the minimum time of entry into the oil and gas generative windows of the two potential source rocks in the region, the Lower Silurian Tannezufft Formation and Middle-Upper Jurassic basinal shales. Maturation modeling suggests that the Lower Silurian source rocks beneath the deeper portions of the Gafsa trough are overmature, even for generation of dry gas. Everywhere north of the Saharan Flexure potential Paleozoic source rocks are highly mature to overmature. The Middle-Upper Jurassic basinal shales in the deeper, central portions of the Gafsa trough entered the oil generative window as early as mid-cretaceous time and into the gas generative window in the Late Cretaceous - early Tertiary. These possible source rocks are mature to highly mature beneath nearly all of the basin. The Gafsa trough is a probable gas province, with occurrences of condensate possible.

  14. 2000 resource assessment of selected coal beds and zones in the Northern and Central Appalachian Basin coal regions

    USGS Publications Warehouse

    Northern and Central Appalachian Basin Coal Regions Assessment Team

    2001-01-01

    This report includes results of a digital assessment of six coal beds or zones in the Northern and Central Appalachian Basin coal regions that produce over 15 percent of the Nation's coal. Other chapters include an executive summary, a report on geology and mining, a report summarizing other selected coal zones that were not assessed, and a report on USGS coal availability and recoverablity studies in the Northern and Central Appalachian Basin coal regions.

  15. Tectono-sedimentary history of the Early Liassic basins of the Central High Atlas (Morocco)

    NASA Astrophysics Data System (ADS)

    Quiquerez, A.; Allemand, P.; Sarih, S.; Garcia, J.-P.

    2012-04-01

    The timing of the opening of the Central High Atlas basins (Morocco) is still debated. Previous works have proposed that the tectonics which started in the Triassic was polyphased and that the Early Liassic was characterized by thermal subsidence before a new phase of extension at the beginning of the Toarcian. In order to precise the timing during the Early Liassic, we have documented a syn-rift succession, in the hanging wall of normal fault segment along a 75 km-long transect (Tizi n' Firest fault). Deposits are composed of massive limestones alternating with marl and gravity-flow related deposits. Field observations have been performed on six sections, 5 to 40 km apart. They include both the description of large-scale architecture from satellite image analysis, the identification of carbonate facies from thin sections, the measurements of sediment transport direction, and also the determination of nine time-lines dated by biochronological markers, from the Sinemurian to the Domerian. This fine chronostratigraphic framework has permitted to delineate and correlate 9 stratigraphical units in 6 sites from the Sinemurian to the Domerian. The reconstructions of detailed temporal and spatial sedimentary patterns along the fault have highlighted a high variability of the syn-rift stratigraphy along the normal fault segments. Two main sub-basins have been defined along this transect. The geometry provided by the time-lines showed that the depocenter were located firstly in the west sub-basin, up to the Carixian, and later in the east sub-basin. The central area remained a low preservation domain during the Early Liassic. Most of the transport directions measured is oriented toward the north, indicating the existence of an active topography on the southern limit of the basin at that time. However, some measurements are oriented toward the east, and this mainly during Domerian, possibly indicating slopes orientated in that direction, suggesting asymmetric fault geometry

  16. Thermal springs in the Payette River basin, west-central Idaho

    SciTech Connect

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

    1980-10-01

    The Payette River basin, characterized by steep, rugged mountains and narrow river valleys, occupies an area of about 3300 square miles in west-central Idaho. Predominant rock types in the basin include granitic rocks of the Idaho batholith and basalt flows of the Columbia River Basalt Group. Waters from thermal springs in the basin, temperatures of which range from 34/sup 0/ to 86/sup 0/ Celsius, are sodium bicarbonate type and are slightly alkaline. Dissolved-solids concentrations range from 173 to 470 milligrams per liter. Reservoir temperatures determined from the sodium-potassium-calcium, silicic acid-corrected silica, and sulfate-water isotope geothermometers range from 53/sup 0/ to 143/sup 0/ Celsius. Tritium, present in concentrations between 0 and 2 tritium units, indicate that sampled thermal waters are at least 100 years and possibly more than 1000 years old. Stable-isotope data indicate it is unlikely any of the nonthermal waters sampled are representative of precipitation that recharges the thermal springs in the basin. Thermal springs discharged about 5700 acre-feet of water in 1979. Associated convective heat flux is 1.1 x 10/sup 7/ calories per second.

  17. Computer model of Raritan River Basin water-supply system in central New Jersey

    USGS Publications Warehouse

    Dunne, Paul; Tasker, Gary D.

    1996-01-01

    This report describes a computer model of the Raritan River Basin water-supply system in central New Jersey. The computer model provides a technical basis for evaluating the effects of alternative patterns of operation of the Raritan River Basin water-supply system during extended periods of below-average precipitation. The computer model is a continuity-accounting model consisting of a series of interconnected nodes. At each node, the inflow volume, outflow volume, and change in storage are determined and recorded for each month. The model runs with a given set of operating rules and water-use requirements including releases, pumpages, and diversions. The model can be used to assess the hypothetical performance of the Raritan River Basin water- supply system in past years under alternative sets of operating rules. It also can be used to forecast the likelihood of specified outcomes, such as the depletion of reservoir contents below a specified threshold or of streamflows below statutory minimum passing flows, for a period of up to 12 months. The model was constructed on the basis of current reservoir capacities and the natural, unregulated monthly runoff values recorded at U.S. Geological Survey streamflow- gaging stations in the basin.

  18. Contrasting red bed diagenesis: the southern and northern margin of the Central European Basin

    NASA Astrophysics Data System (ADS)

    Schöner, Robert; Gaupp, Reinhard

    2005-12-01

    We compare the diagenetic evolution of deeply buried Rotliegend (Permian) red bed sandstones at the southern and northern margin of the Central European Basin (CEB) in Germany. Main target is to evaluate the influence of maturation products from hydrocarbon (HC) source rocks during red bed diagenesis. At the southern margin of the CEB, thick coal-bearing Carboniferous source rocks are omnipresent beneath the Rotliegend. They contain dominantly gas-prone terrigenous organic material and some oil source rocks. Hydrocarbons were generated from Late Carboniferous onwards throughout most of basin subsidence. At the northern margin of the CEB, source rocks are almost absent due to deep erosion of Carboniferous rocks and a low TOC of local Lower Carboniferous relics. Early diagenetic processes are comparable at both basin margins. Significant differences in burial diagenetic evolution are spatially correlated to the occurrence of hydrocarbon source rocks. Burial diagenesis at the southern margin of the CEB is characterized especially by bleaching of red beds, major dissolution events, pervasive illite formation, impregnation of pore surfaces with bitumen, and formation of late Fe-rich cements. Almost none of these features were detected at the northern basin margin. Instead, relatively early cements are preserved down to maximum burial depths. This suggests that major diagenetic mineral reactions in deeply buried red bed sandstones are controlled by the presence or absence of maturing hydrocarbon source rocks.

  19. Stratigraphic analysis of the carboniferous rocks of the Central Appalachian Basin

    SciTech Connect

    Chesnut, D.R. Jr.

    1988-01-01

    A series of seven cross sections was constructed across part of the Central Appalachian Basin in Kentucky, Tennessee, Virginia, West Virginia, and Ohio. Information used to make these sections included well logs, coal-company core descriptions, measured sections, and mapped surface geology. Newly discovered surface and subsurface structural features such as faults, folds, and flexures, are described. A new, unofficial lithostratigraphic nomenclature was introduced to illustrate the stratigraphic framework, and a regional unconformity was interpreted to occur between the Pennsylvanian Pocahontas Formation and the Pennsylvanian New River Formation. The cross sections reveal that sequential truncation of formations below the unconformity occurs t the northwest in the basin. A regional unconformity and biostratigraphic evidence indicate that the Carboniferous rocks were deposited in a series of several small-scale environmental continua. Pennsylvanian rocks overlying the regional unconformity sequentially overlap the underlying rocks to the northwest in the basin. Belts of quartzose sandstones (Lee Formation) within the overlying rocks, are oriented northeast-southwest. Succeeding sandstone belts onlap the unconformity to the northwest within the basin. A fluvial origin is suggested for the quartzose, conglomeratic sands of the Lee Formation. The source for these sands may have been reworked sediments derived from the Old Red Sandstone continent to the northwest in Canada. The remaining Pennsylvanian coal-bearing clastic rocks (Breathitt Group) were deposited as clastic wedges derived from the east and southeast on coastal lowlands.

  20. Tectonic Evolution of the Çayirhan Neogene Basin (Ankara), Central Turkey

    NASA Astrophysics Data System (ADS)

    Behzad, Bezhan; Koral, Hayrettin; İşb&idot; l, Duygu; Karaaǧa; ç, Serdal

    2016-04-01

    Çayırhan (Ankara) is located at crossroads of the Western Anatolian extensional region, analogous to the Basin and Range Province, and suture zone of the Neotethys-Ocean, which is locus of the North Anatolian Transform since the Late Miocene. To the north of Çayırhan (Ankara), a Neogene sedimentary basin comprises Lower-Middle Miocene and Upper Miocene age formations, characterized by swamp, fluvial and lacustrine settings respectively. This sequence is folded and transected by neotectonic faults. The Sekli thrust fault is older than the Lower-Middle Miocene age formations. The Davutoǧlan fault is younger than the Lower-Middle Miocene formations and is contemporaneous to the Upper Miocene formation. The Çatalkaya fault is younger than the Upper Miocene formation. The sedimentary and tectonic features provide information on mode, timing and evolution of this Neogene age sedimentary basin in Central Turkey. It is concluded that the region underwent a period of uplift and erosion under the influence of contractional tectonics prior to the Early-Middle Miocene, before becoming a semi-closed basin under influence of transtensional tectonics during the Early-Middle Miocene and under influence of predominantly extensional tectonics during the post-Late Miocene times. Keywords: Tectonics, Extension, Transtension, Stratigraphy, Neotectonic features.

  1. Influence of orogenesis in basin evolution in the central Asian republics of the CIS

    SciTech Connect

    Otto, S.

    1995-08-01

    A regional synthesis of the structural geology of the central Asia region of the CIS is presented, the study area lying between the Caspian Sea and China and stretching from the Aral Sea south to Afghanistan. Structural analysis of central Asia illustrates the creation of major regional faults that have acted as planes of weakness during the evolution of the region. These faults were repeatedly reactivated in phases of orogenesis, some of which were centred far from the study area. It is shown that the Eurasian Plate did not act as a rigid, unyielding lithospheric unit, but deformed internally as a response to compression at its margins. The influence of these orogenic events on the evolution of basins in the area is described by means of maps and serial sections. The role of major faults in governing the spatial distribution of structural traps in petroleum basins within the study area is also examined. These basins are largely gas-prone, and have ultimate recoverable reserves estimated at over 290 trillion cubic feet of gas and 27 billion barrels of liquids.

  2. Long-term spatial distributions and trends of ambient CO concentrations in the central Taiwan Basin

    NASA Astrophysics Data System (ADS)

    Lin, Yu Chi; Lan, Yung Yao; Tsuang, Ben-Jei; Engling, Guenter

    2008-06-01

    Long-term spatial distributions and trends of atmospheric carbon monoxide (CO) concentrations in the central Taiwan Basin were investigated by analysis of CO data obtained from the Taiwan Air Quality Monitoring Network (TAQMN). The influence of meteorological conditions on the CO patterns was also analyzed in this paper. The results showed the highest CO concentrations were found in the vicinity of urban areas with a 13-yr mean value of 0.79±0.16 ppm. This was associated with the most intensive anthropogenic CO emissions at the urban sites. For all sites, lower CO levels were consistently observed during the summer season. This was explained by favorable conditions for dispersion and loss of CO via photochemical reactions. Analysis of wind fields and backward trajectories revealed that two types of synoptic sea breezes directly influenced the CO spatial distributions in the basin. During autumn to spring, northerly flow accompanied by pollutants traveled to inland areas, resulting in higher CO concentrations in the remote areas. During summer, breezes coming from the sea or areas to the south with lower CO emissions, resulted in more uniform spatial distributions of CO in the study region. While CO concentrations exhibited decreasing trends, the average CO mixing ratio from 1994 through 2006 decreased at a rate of approximately 0.02 ppm yr-1 in the central Taiwan Basin.

  3. Stratigraphy, sedimentology and paleontology of lower Eocene San Jose formation, central San Juan basin, New Mexico

    SciTech Connect

    Lucas, S.G.; Smith, L.N. )

    1989-09-01

    The lower Eocene San Jose Formation in the central portion of the San Juan basin (Gobernador-Vigas Canyon area) consists of the Cuba Mesa, Regina, Llaves, and Tapicitos Members. Well log data indicate that, from its 100-m thickness, the Cuba Mesa Member thins toward the basin center and pinches out to the northeast by lat. 36{degree}40'N, long. 107{degree}19'W. The Regina Member has the most extensive outcrops in the central basin, and it decreases in sandstone/mud rock ratio to the north. The Llaves and Tapicitos Members occur only at the highest elevations, are thin due to erosion, and are not mappable as separate units. Well log data and 1,275 m of measured stratigraphic section in the Regina, Llaves, and Tapicitos Members indicate these strata are composed of approximately 35% medium to coarse-grained sandstone and 65% fine-grained sandstone and mud rock. Sedimentology and sediment-dispersal patterns indicate deposition by generally south-flowing streams that had sources to the northwest, northeast, and east. Low-sinuosity, sand-bedded, braided( ) streams shifted laterally across about 1 km-wide channel belts to produce sheet sandstones that are prominent throughout the San Jose Formation. Subtle levees separated channel environments from floodplain and local lacustrine areas. Avulsion relocated channels periodically to areas on the floodplain, resulting in the typically disconnected sheet sandstones within muddy overbank deposits of the Regina Member.

  4. Holocene mammalian change in the central Columbia Basin of eastern Washington state, USA

    NASA Astrophysics Data System (ADS)

    Lyman, R. Lee

    2016-08-01

    Predictions of changes in the Holocene mammalian fauna of the central Columbia Basin in eastern Washington (USA) based on environmental changes are largely met. Taxonomic richness is greatest during periods of cool-moist climate. Rates of input of faunal remains to the paleozoological record may suggest greater mammalian biomass during periods of greater moisture but are difficult to interpret without data on sampling intensity in the form of volume of sediment excavated. Abundances of leporids and grazing ungulates fluctuate in concert with abundance of grass. Several biogeographic records are tantalizing but require additional study and data before being accepted as valid. Records of red fox (Vulpes vulpes) indicate this species was present in the central basin during the Holocene contrary to historic records and recent suggestions modern foxes there are escapees from fur farms. Bison (Bison bison) and bighorn sheep (Ovis canadensis) underwent diminution of body size during the Holocene. Modern efforts to conserve the Columbia Basin ecosystem are advised to consider the Holocene record as indicative of what may happen to that ecosystem in the future.

  5. Evolution of the east-central San Jose del Cabo basin, Baja California Sur, Mexico

    NASA Astrophysics Data System (ADS)

    McTeague, M. S.; Umhoefer, P. J.; Schwennicke, T.; Ingle, J. C.; Cortes Martinez, M.

    2006-12-01

    The San Jose del Cabo basin at the southern tip of the Baja California peninsula records the early tectonic evolution of the west side of the Gulf of California. This study focused on the east central margin of the basin. The basal La Calera Formation unconformably overlies Cretaceous granite and consists of conglomerate, pebbly sandstone and conglomerate, and sandstone deposited in alluvial fans and fan-deltas. Deposition of the La Calera Formation was from ca. 9-14 Ma. The lower member of the Trinidad Formation was deposited beginning ca. 9-13 Ma and consists of sandstone, mudstone, and shelly mudstone deposited in nearshore and estuarine environments. These age estimates are based on sedimentation rates and foraminifera and coccoliths from the NN 11A nannozone (7.4 8.6 Ma, GTS 2004). The middle member of the Trinidad Formation consists of deeper water mudstones deposited by turbidity currents and suspension settling in a shelf to slope and conglomerates deposited by submarine debris flows on the shelf. The basin began earlier than previously thought. The oldest marine rocks are ca.9-13 Ma, while sedimentation on the east side began at ca. 9-14 Ma, synchronous with estimates of initiation of offset on the San Jose del Cabo fault. The Zapote fault is a down-to-the-east normal and sinistral-oblique fault that exposes a wedge of granite and older strata in the footwall to the west. The fault was active during sedimentation in the late Miocene and possibly later. The fault divides the study area into an eastern hanging wall subbasin and western footwall subbasin. The eastern subbasin formed an embayment in the eastern margin of the Cabo basin. A regional flooding surface (ca. 8 Ma) can be correlated across the fault that marks a major marine incursion. Depositional systems evolved rapidly from coarse-grained terrestrial systems to fine-grained marine and estuarine systems. The Cabo basin provides an excellent analogue for comparison with offshore basins, which are

  6. Federally owned coal and Federal lands in the Northern and Central Appalachian Basin coal regions

    USGS Publications Warehouse

    Tewalt, S.J.

    2002-01-01

    The U.S. Geological Survey (USGS) assessed five coal beds or coal zones in the northern and central Appalachian Basin coal regions for the National Coal Resource Assessment: the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay coal zone, the Pond Creek coal zone, and the Pocahontas No. 3 coal bed. The assessment produced stratigraphic and geochemical databases and digital coal maps, or models, which characterized the coal beds and coal zones. Using the assessment models, the USGS estimated original and remaining (unmined) resources for these coal beds or zones. The Appalachian Basin assessment was conducted in collaboration with the State geological surveys of West Virginia, Pennsylvania, Ohio, Maryland, Kentucky, and Virginia.

  7. Sirte Basin, north-central Libya: Cretaceous rifting above a fixed mantle hotspot?

    NASA Astrophysics Data System (ADS)

    van Houten, Franklyn B.

    1983-02-01

    The complex pattern of horsts and grabens in the Sirte Basin may have developed when Mesozoic drift of the African plate put north-central Libya over a fixed mantle hotspot in Early Cretaceous time (140 to 100 m.y. ago). Significant change in the motion of the plate during the prolonged residence above a hypothetical Cameroon plume may have produced stress that fragmented thinned and weakened lithosphere. Successive uplift and subsidence along a reconstructed track of the plume, as well as in the Sirte Basin, are compatible with predicted effects of the drift of northern Africa over a fixed mantle hotspot. This speculation suggests a plausible alternative to the possibility that rifting throughout northern Africa in Early Cretaceous time may have been produced along a wide zone of extension between two African plates when they were at rest relative to underlying plumes.

  8. Federally owned coal and Federal lands in the northern and central Appalachian Basin coal regions

    SciTech Connect

    Susan J. Tewalt

    2002-02-01

    The US Geological Survey (USGS) assessed five coals beds or coal zones in the northern and central Appalachian Basin coal regions for the National Coal Resource Assessment: the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay coal zone, the Pond Creek coal zone, and the Pocahontas No. 3 coal bed. The assessment produced stratigraphic and geochemical databases and digital coal maps, or models, which characterized the coal beds and coal zones. Using the assessment models, the USGS estimated original and remaining (unmined) resources for these coal beds or zones. The Appalachian Basin assessment was conducted in collaboration with the State geological surveys of West Virginia, Pennsylvania, Ohio, Maryland, Kentucky, and Virginia. 3 refs., 7 figs.

  9. Coal resources of selected coal beds and zones in the northern and central Appalachian Basin

    SciTech Connect

    Leslie Ruppert; Susan Tewalt; Linda Bragg

    2002-02-01

    The U.S. Geological Survey (USGS) is completing a National Coal Resource Assessment of five coal-producing regions of the United States, including the Appalachian Basin. The USGS, in cooperation with the State geological surveys of Kentucky, Maryland, Ohio, Pennsylvania, Virginia, and West Virginia, has completed a digital coal resource assessment of five of the top-producing coal beds and coal zones in the northern and central Appalachian Basin coal regions -- the Pittsburgh coal bed, the Upper Freeport coal bed, the Fire Clay and Pond Creek coal zones, and the Pocahontas No. 3 coal bed. Of the 93 billion short tons of original coal in these units, about 66 billion short tons remain. 2 refs., 5 figs., 2 tabs.

  10. Mechanisms of Pacific Summer Water variability in the Arctic's Central Canada Basin

    NASA Astrophysics Data System (ADS)

    Timmermans, M.-L.; Proshutinsky, A.; Golubeva, E.; Jackson, J. M.; Krishfield, R.; McCall, M.; Platov, G.; Toole, J.; Williams, W.; Kikuchi, T.; Nishino, S.

    2014-11-01

    Pacific Water flows northward through Bering Strait and penetrates the Arctic Ocean halocline throughout the Canadian Basin sector of the Arctic. In summer, Pacific Summer Water (PSW) is modified by surface buoyancy fluxes and mixing as it crosses the shallow Chukchi Sea before entering the deep ocean. Measurements from Ice-Tethered Profilers, moorings, and hydrographic surveys between 2003 and 2013 reveal spatial and temporal variability in the PSW component of the halocline in the Central Canada Basin with increasing trends in integrated heat and freshwater content, a consequence of PSW layer thickening as well as layer freshening and warming. It is shown here how properties in the Chukchi Sea in summer control the temperature-salinity properties of PSW in the interior by subduction at isopycnals that outcrop in the Chukchi Sea. Results of an ocean model, forced by idealized winds, provide support to the mechanism of surface ocean Ekman transport convergence maintaining PSW ventilation of the halocline.

  11. Porosity evolution in reservoir sandstones in the West-Central San Joaquin basin, California

    SciTech Connect

    Horton, R.A. Jr.; McCullough, P.T.; Houghton, B.D.; Pennell, D.A.; Dunwoody, J.A. III; Menzie, R.J. Jr.

    1995-04-01

    Miocene reservoir sands (feldspathic and lithic arenites) in central San Joaquin basin oil fields show similar trends in porosity development despite differences in depositional environment, pore-fluid chemistry, and burial history. Burial and tectonic compaction caused grain rotation, deformation of altered lithics, and extensive fracturing of brittle grains, thereby eliminating most primary porosity. Diagenetic fluids, infiltrating along fractures in grains, reacted with freshly exposed mineral surfaces causing extensive leaching of framework components. All major grain types were affected but preferential removal of feldspars and lithics resulted in changes in QFL ratios. With continued compaction angular remnants of partially disolved grains were rotated and rearranged while secondary intergranular and moldic porosity collapsed to form secondary intergranular porosity. This resulted in reservoir sands that are less well sorted, more angular, and mineralogically more mature than they were at deposition. Such changes appear to widespread in the San Joaquin basin and may be more important than is generally acknowledged.

  12. 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.

  13. Flood of July 9-11, 1993, in the Raccoon River basin, west-central Iowa

    USGS Publications Warehouse

    Eash, D.A.; Koppensteiner, B.A.

    1997-01-01

    Water-surface-elevation profiles and peak discharges for the flood of July 9-11, 1993, in the Raccoon River Basin, west-central Iowa, are presented in this report. The profiles illustrate the 1993 flood along the Raccoon, North Raccoon, South Raccoon, and Middle Raccoon Rivers and along Brushy and Storm Creeks in the west-central Iowa counties of Carroll, Dallas, Greene, Guthrie, and Polk. Water-surface-elevation profiles for the floods of June 1947, March 1979, and June 29- July 1, 1986, in the Raccoon River Basin also are included in the report for comparative purposes. The July 9-11, 1993, flood is the largest known peak discharge at gaging stations Brushy Creek near Templeton (station number 05483318) 19,000 cubic feet per second, Middle Raccoon River near Bayard (station number 05483450) 27,500 cubic feet per second, Middle Raccoon River at Panora (station number 05483600) 22,400 cubic feet per second, South Raccoon River at Redfield (station number 05484000) 44,000 cubic feet per second, and Raccoon River at Van Meter (station number 05484500) 70,100 cubic feet per second. The peak discharges were, respectively, 1.5, 1.3, 1.1,1.2, and 1.3 times larger than calculated 100-year recurrence-interval discharges. The report provides information on flood stages and discharges and floodflow frequencies for streamflow-gaging stations in the Raccoon River Basin using flood information collected through 1996. A flood history summarizes rainfall conditions and damages for floods that occurred during 1947, 1958, 1979, 1986, 1990, and 1993. Information on temporary bench marks and reference points established in the Raccoon River Basin during 1976-79 and 1995-97 also is included in the report.

  14. Paleoseismological investigations and Geomorphology on the Gaenserndorf Terrace in the central Vienna Basin (Austria)

    NASA Astrophysics Data System (ADS)

    Weissl, Michael; Hintersberger, Esther; Lomax, Johanna; Decker, Kurt

    2016-04-01

    In the central Vienna Basin normal faults define the eastern and western margins of Pleistocene Danube terraces north of Vienna. The terrace body is built up of coarse sandy gravel and sand. Locally the terrace surface is covered with eolian and alluvial sediments of the last glacial revealing OSL/IRSL ages of about 15-16 ka. High resolution digital terrain models (LIDAR) show relicts of a periglacial landscape in the northern part of the Middle Pleistocene (MIS 8) terrace. Large elongated depressions in the northern parts of the terrace are interpreted as the basins of former thermokarst lakes due to analogies in recent periglacial zones. Draining valleys corrugate the fault scarps indicating advanced subsidence of the Aderklaa and Obersiebenbrunn Quaternary basins before the last Glacial. Obviously the periglacial morphology is only preserved in the elevated parts of the terrace which is located in the footwall of the bounding normal faults. In the hanging wall Quaternary basins are filled with up to 40 m thick Pleistocene and Holocene growth strata. During the last decade three faults were investigated by trenching. In contrast to the earlier trench sites on the Markgrafneusiedl Fault and the Vienna Basin Transform Fault it was not possible to provide clear evidence for offset on the Aderklaa-Bockfliess fault because cryoturbation deformed the covering fluvial sediments together with the underlying Gaenserndorf terrace gravels. However it was possible to localize this fault precisely applying an electrical resistivity tomography. The resulting ERT-section shows an offset of the 200-300 ky old terrace and the underlying Miocene sediments of about 9-10 meters suggesting a vertical slip rate of 0.03 - 0.05 mm/a.

  15. Linking carbon storage with functional diversity in tropical rainforest in the central Congo Basin

    NASA Astrophysics Data System (ADS)

    Verbeeck, Hans; Kearsley, Elizabeth; Bauters, Marijn; Beeckman, Hans; Huygens, Dries; Steppe, Kathy; Boeckx, Pascal

    2015-04-01

    This presentation will show an overview of results of the COBIMFO project (Congo basin integrated monitoring for forest carbon mitigation and biodiversity). In the framework of this project we have established 21 permanent 1 ha sampling plots in different forest types in the Yangambi reserve. This UNESCO Man and Biosphere reserve has an area of more than 6000 km² and is located in the heart of the Congo Basin near the Yangambi research station (DR Congo). Analysis of the inventory data of these plots revealed that carbon stocks in mature forests in this area of the Congo Basin are significantly lower (24%) than stocks recorded in the outer regions of the basin. These lower stocks are attributed to a lower maximal tree height (Kearsley et al. 2013). In addition to the carbon inventories we collected leaf and wood samples on all species within 95% basal area of each of the Yangambi plots. A total of 995 individuals were sampled, covering 123 tree species. On the samples we measured 15 traits related to leaf and wood morphology and functioning. In the presented study, relationships between the observed functional diversity and biomass are analysed. One of the remarkable results of our analysis is that species with a high functional distinctiveness have a low contribution to the basal area and the carbon stocks. In contrast, species with a high contribution to the carbon stock have a low contribution to the functional diversity. Similar patterns have been observed elsewhere (e.g. Amazon basin), but are now for the first time confirmed for central African rainforest. Finally, we also present the first results of an analysis of carbons stocks and functional diversity in tropical plantations from a unique 70-years old tree diversity experiment that was established during the colonial period at the Yangambi research station. Kearsley, E., de Haulleville, T., Hufkens, K., Kidimbu, A., Toirambe, B., Baert, G., Huygens, D., Kebede, Y., Defourny, P., Bogaert, J., Beeckman, H

  16. Explosive Components Facility at Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Not Available

    1992-07-01

    The United States Department of Energy (DOE) has prepared an environmental assessment (EA) on the proposed Explosive Components Facility (ECF) at the Sandia National Laboratories, Albuquerque (SNL). This facility is needed to integrate, centralize, and enhance many of the explosive, neutron generation, and weapons testing programs currently in progress at SNL. In general, there is insufficient space in existing facilities for the development and testing activities required by modern explosives technologies. The EA examined the potential environmental impacts of the proposed ECF project and discussed potential alternatives. Based on the analyses in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969, and CEQ regulations at 40 CFR 1508.18 and 1508.27. Therefore, an environmental impact statement (EIS) is not required, and the DOE is issuing this Finding of No Significant Impact (FONSI).

  17. Three extensional basin types associated with detachment-style faulting, early Miocene of the central Mojave Desert

    SciTech Connect

    Fillmore, R.P.; Walker, J.D. . Dept. of Geology)

    1993-04-01

    Three distinct extensional basin types, formed synchronously in different structural settings, have been identified in the central Mojave Desert and provide a basis for the paleogeographic reconstruction of extension of the central Mojave metamorphic core complex (CMMCC). From west to east, the Tropico, Pickhandle, and Clews basins formed in the footwall, on the breakaway, and well within the hanging wall of the east-rooting detachment fault system of the CMMCC. The Tropico basin was created by crustal-scale flexure of the little extended footwall behind the breakaway of the detachment. The basin was shallow and areally extensive. Lower strata on the eastern margin comprise fluvial sandstone derived from the adjacent highland; these grade up into lacustrine deposits. The Pickhandle rift basin is a half graben that was bounded to the west by the detachment escarpment. Initially the basin was deep and narrow, and elongate parallel to the detachment. Basin fill consists of megabreccia, conglomerate derived from both the footwall and hanging wall, and synextensional volcanic rocks. The Clews basin developed within the hanging wall, and synextensional volcanic rocks. The Clews basin developed within the hanging wall. Basal lacustrine strata record initial downwarping. The overlying coarsening-upwards clastic sequence, derived from the east, reflects the propagation of a west-dipping normal fault on the east basin margin that is interpreted to sole into the detachment that probably extended beneath the area from the west. Sediment deposited in extensional basins contain a record of early phase extension that is not obtainable by other types of studies. The recognition of footwall-uplift, breakaway rift, and intra-hanging wall basin types in highly extended terranes may aid in the reconstruction of features that have been modified, such as the position of the detachment breakaway zone, and the areal extent of extensional deformation.

  18. Basement structural control on Cretaceous pull-apart basins of the central Eastern Egypt Desert

    NASA Astrophysics Data System (ADS)

    McCaffrey, K.; El Kazzaz, Y.; Holdsworth, B.

    2006-12-01

    The present-day Red Sea / Gulf of Suez rift system is attributed to extensional block faulting with along-axis segmentation into sub-basins with different dip polarities. The northwestern margin of the Red Sea - Gulf of Suez rift system is exposed for about 400 km along the northwestern Red Sea coast near Quseir to the tip of the Gulf of Suez at Suez City. This area contains elements of the pre-Red Sea structural pattern which has been viewed in similar terms as one of fault-related basin formation. Four distinct depocenters (sub-basins) separated by complex accommodation zones are present containing 500-700m thick section ranging in age from the Late Cretaceous to the Middle Eocene. Each sub-basin is asymmetric, bounded on one side by a major NW-trending border fault system with large throws (3-6 km in general) with a dominant strata dip direction toward the border fault system. These basins are arranged in en echelon patterns and now form separate elongated ridges surrounded by basement rocks. Our study of the tectonic evolution of the central eastern section of the Gulf of Suez rift and the Northwestern Red Sea has focused on the interaction of pre-existing basement fabrics with the pre-Red Sea structural development. The study involved analysis of LandsatTM images and aerial photographs integrated with results from reconnaissance geological mapping. Our provisional results indicate that the Gebel Um Hammad/Duwi and Hammadat sub-basins were sited in pull-apart structures created by dextral reactivation of E-W to ENE-WSW trending basement fault zones. We show how the basin-bounding fault systems, lower order normal faults and folds in both hangingwall sequences and in basement are compatible with a Late Cretaceous to Early Eocene strike-slip regime. In contrast, the main Red Sea Gulf of Suez rift shows no evidence for strike-slip influence with the main boundary faults cutting across basement fabrics, however, as pointed out by previous authors, rift segmentation

  19. Physical Characteristics of Stream Subbasins in the Redeye (Leaf) River Basin, Central Minnesota

    USGS Publications Warehouse

    Sanocki, Christopher A.; Fischer, Brian C.

    2000-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Redeye (Leaf) River Basin, located in 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, and locations of U.S. Geological Survey high-flow, and continuous-record gaging stations.

  20. Selected hydrologic data for Fountain Creek and Monument Creek basins, east-central Colorado

    USGS Publications Warehouse

    Kuhn, Gerhard; Ortiz, Roderick F.

    1989-01-01

    Selected hydrologic data were collected during 1986, 1987, and 1988 by the U.S. Geological Survey for the Fountain Creek and Monument Creek basins, east-central Colorado. The data were obtained as part of a study to determine the present and projected effects of wastewater discharges on the two creeks. The data, which are available for 129 surface-water sites, include: (1) About 1,100 water quality analyses; (2) about 420 measurements of discharge, (3) characteristics of about 50 dye clouds associated with measurements of traveltime and reaeration , and (4) about 360 measurements of channel geometry. (USGS)

  1. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini; Donald A. Goddard

    2005-08-01

    The principal research effort for Year 3 of the project is basin modeling and petroleum system identification, comparative basin evaluation and resource assessment. In the first six (6) months of Year 3, the research focus is on basin modeling and petroleum system identification and the remainder of the year the emphasis is on the comparative basin evaluation and resource assessment. No major problems have been encountered to date, and the project is on schedule.

  2. INTEGRATING GEOPHYSICS, GEOLOGY, AND HYDROLOGY TO DETERMINE BEDROCK GEOMETRY CONTROLS ON THE ORIGIN OF ISOLATED MEADOW COMPLEXES WITHIN THE CENTRAL GREAT BASIN, NEVADA

    EPA Science Inventory

    Riparian meadow complexes found in mountain ranges of the Central Great Basin physiographic region (western United States) are of interest to researchers as they contain significant biodiversity relative to the surrounding basin areas. These meadow complexes are currently degradi...

  3. Status and Understanding of Groundwater Quality in the Central-Eastside San Joaquin Basin, 2006: California GAMA Priority Basin Project

    USGS Publications Warehouse

    Landon, Matthew K.; Belitz, Kenneth; Jurgens, Bryant C.; Justin T. Kulongoski, Justin T.; Johnson, Tyler D.

    2010-01-01

    Groundwater quality in the approximately 1,695-square-mile Central Eastside San Joaquin Basin (Central Eastside) study unit was investigated as part of the Priority Basin Project (PBP) of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA PBP was developed in response to the California Groundwater Quality Monitoring Act of 2001, and is being conducted by the California State Water Resources Control Board in collaboration with the U.S. Geological Survey and the Lawrence Livermore National Laboratory. The GAMA Central Eastside study unit was designed to provide a spatially unbiased assessment of untreated-groundwater quality, as well as a statistically consistent basis for comparing water quality throughout California. During March through June 2006, samples were collected from 78 wells in Stanislaus and Merced Counties, 58 of which were selected using a spatially distributed, randomized grid-based method to provide statistical representation of the study unit (grid wells), and 20 of which were sampled to evaluate changes in water chemistry along groundwater-flow paths (understanding wells). Water-quality data from the California Department of Public Health (CDPH) database also were used for the assessment. An assessment of the current status of the groundwater quality included collecting samples from wells for analysis of anthropogenic constituents such as volatile organic compounds (VOCs) and pesticides, as well as naturally occurring constituents such as major ions and trace elements. The assessment of status is intended to characterize the quality of untreated-groundwater resources within the primary aquifer system, not the treated drinking water delivered to consumers by water purveyors. The primary aquifer system (hereinafter, primary aquifer) is defined as that part of the aquifer corresponding to the perforation interval of wells listed in the CDPH database for the Central Eastside study unit. The quality of groundwater in shallower or

  4. Impact of structural and autocyclic basin-floor topography on the depositional evolution of the deep-water Valparaiso forearc basin, central Chile

    USGS Publications Warehouse

    Laursen, J.; Normark, W.R.

    2003-01-01

    The Valparaiso Basin constitutes a unique and prominent deep-water forearc basin underlying a 40-km by 60-km mid-slope terrace at 2.5-km water depth on the central Chile margin. Seismic-reflection data, collected as part of the CONDOR investigation, image a 3-3.5-km thick sediment succession that fills a smoothly sagged, margin-parallel, elongated trough at the base of the upper slope. In response to underthrusting of the Juan Ferna??ndez Ridge on the Nazca plate, the basin fill is increasingly deformed in the seaward direction above seaward-vergent outer forearc compressional highs. Syn-depositional growth of a large, margin-parallel monoclinal high in conjunction with sagging of the inner trough of the basin created stratal geometries similar to those observed in forearc basins bordered by large accretionary prisms. Margin-parallel compressional ridges diverted turbidity currents along the basin axis and exerted a direct control on sediment depositional processes. As structural depressions became buried, transverse input from point sources on the adjacent upper slope formed complex fan systems with sediment waves characterising the overbank environment, common on many Pleistocene turbidite systems. Mass failure as a result of local topographic inversion formed a prominent mass-flow deposit, and ultimately resulted in canyon formation and hence a new focused point source feeding the basin. The Valparaiso Basin is presently filled to the spill point of the outer forearc highs, causing headward erosion of incipient canyons into the basin fill and allowing bypass of sediment to the Chile Trench. Age estimates that are constrained by subduction-related syn-depositional deformation of the upper 700-800m of the basin fill suggest that glacio-eustatic sea-level lowstands, in conjunction with accelerated denudation rates, within the past 350 ka may have contributed to the increase in simultaneously active point sources along the upper slope as well as an increased

  5. Analysis of 1997–2008 groundwater level changes in the upper Deschutes Basin, Central Oregon

    USGS Publications Warehouse

    Gannett, Marshall W.; Lite, Kenneth E., Jr.

    2013-01-01

    Groundwater-level monitoring in the upper Deschutes Basin of central Oregon from 1997 to 2008 shows water-level declines in some places that are larger than might be expected from climate variations alone, raising questions regarding the influence of groundwater pumping, canal lining (which decreases recharge), and other human influences. Between the mid-1990s and mid-2000s, water levels in the central part of the basin near Redmond steadily declined as much as 14 feet. Water levels in the Cascade Range, in contrast, rose more than 20 feet from the mid-1990s to about 2000, and then declined into the mid-2000s, with little or no net change. An existing U.S. Geological Survey regional groundwater-flow model was used to gain insights into groundwater-level changes from 1997 to 2008, and to determine the relative influence of climate, groundwater pumping, and irrigation canal lining on observed water-level trends. To utilize the model, input datasets had to be extended to include post-1997 changes in groundwater pumping, changes in recharge from precipitation, irrigation canal leakage, and deep percolation of applied irrigation water (also known as on-farm loss). Mean annual groundwater recharge from precipitation during the 1999–2008 period was 25 percent less than during the 1979–88 period because of drying climate conditions. This decrease in groundwater recharge is consistent with measured decreases in streamflow and discharge to springs. For example, the mean annual discharge of Fall River, which is a spring-fed stream, decreased 12 percent between the 1979–88 and 1999–2008 periods. Between the mid-1990s and late 2000s, groundwater pumping for public-supply and irrigation uses increased from about 32,500 to 52,000 acre-feet per year, partially because of population growth. Between 1997 and 2008, the rate of recharge from leaking irrigation canals decreased by about 58,000 acre-feet per year as a result of lining and piping of canals. Decreases in recharge

  6. Availability of ground water in the middle Merrimack River basin, central and southern New Hampshire

    USGS Publications Warehouse

    Cotton, J.E.

    1976-01-01

    Sufficient amounts of water to supply single family homes are available from the bedrock aquifer nearly everywhere in the middle Merrimack River basin in central and southern New Hampshire. Relatively this and narrow, unconsolidated aquifers of sand or sand and gravel commonly capable of yielding more than 200 gallons per minute to properly located and constructed wells are found only in major stream valleys. The map provides a preliminary assessment of the availability of ground water in the basin, as determined by estimating the capability of the aquifers to store and transmit water. On the map, aquifers are rated as having high, medium, or low potential to yield water. Ground water in the middle Merrimack River basin is generally of good chemical quality. Most of it is clear and colorless, contains no suspended matter and practically no bacteria, water may be affected by land-use practices. Degradation of water quality may occur in unsewered residential and village areas, near solid-waste-disposal sites, agricultural land, and major highways. (Woodard-USGS)

  7. 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.

  8. 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.

  9. Spatial Analysis of Suitability for Managed Aquifer Recharge in a Groundwater Basin in Central Coastal California

    NASA Astrophysics Data System (ADS)

    Russo, T. A.; Fisher, A. T.; Hanson, R. T.; Lockwood, B. S.

    2011-12-01

    The Pajaro Valley Groundwater Basin (PVGB), central coastal California, relies almost entirely on groundwater to satisfy agricultural and municipal/domestic needs (83% and 17% of water usage, respectively). The rate of groundwater extraction and other outflows from the PVGB over the last five decades has exceeded the total rate of inflows, resulting in chronic overdraft. This has led to a lowering of water levels throughout the basin and seawater intrusion near the coast. Managed aquifer recharge (MAR) likely will become increasingly important for sustaining groundwater supply in future years; however, identifying areas amenable to MAR remains challenging. A geographical information system (GIS) analysis was completed to evaluate areas of the PVGB suitable for MAR. Initially GIS analyses used topographic, land use, bedrock geology, and soil property data to assess shallow conditions, and subsequent analyses have included subsurface information such as aquifer and associated confining layer locations, properties, thicknesses, and historical changes in water levels. Additional GIS coverages included potential supplemental water supplies. A preliminary map of MAR site suitability suggests that about 10% of the basin may be suitable for MAR. Ongoing field testing will provide "ground truth" for the assessment of GIS-based calculations, and both field and GIS analyses will provide critical input for regional hydrologic models that will be used to quantify the potential influences of different MAR scenarios. Collectively, these studies are helping to evaluate management options for improving long-term groundwater conditions throughout the PVGB.

  10. Albuquerque Seismological Laboratory--50 years of global seismology

    USGS Publications Warehouse

    Hutt, C.R.; Peterson, Jon; Gee, Lind; Derr, John; Ringler, Adam; Wilson, David

    2011-01-01

    The U.S. Geological Survey Albuquerque Seismological Laboratory is about 15 miles southeast of Albuquerque on the Pueblo of Isleta, adjacent to Kirtland Air Force Base. The Albuquerque Seismological Laboratory supports the Global Seismographic Network Program and the Advanced National Seismic System through the installation, operation, and maintenance of seismic stations around the world and serves as the premier seismological instrumentation test facility for the U.S. Government.

  11. Eustatic control on epicontinental basins: The example of the Stuttgart Formation in the Central European Basin (Middle Keuper, Late Triassic)

    NASA Astrophysics Data System (ADS)

    Franz, M.; Nowak, K.; Berner, U.; Heunisch, C.; Bandel, K.; Röhling, H.-G.; Wolfgramm, M.

    2014-11-01

    The deposition of the Stuttgart Formation ('Schilfsandstein'), commonly considered as a type-example of the Carnian Pluvial Event, was controlled by high frequent 4th order sequences that resulted in pre-, intra- and post-Schilfsandstein transgressions from Tethyan waters into the epicontinental Central European Basin (CEB). The pre-Schilfsandstein transgression flooded the CEB trough gates to the Southeast and resulted in a wide-spread inland sea that was characterised by increased biological productivity, predominantly oxic conditions and enabled the immigration of euryhaline marine fauna with plankton, ostracodes, fishes, bivalves and the gastropods Omphaloptychia suebica n. sp. and Settsassia stuttgartica n. sp. The rather short-term intra- and post-Schilfsandstein transgressions flooded the CEB from the Southwest and Southeast and established a shallow brackish inland sea that stretched up to North Germany. Both, the 4th and 3rd order sequences derived from the succession in the CEB correlate well with those derived from successions of Tethyan shelfs. Therefore pronounced circum-Tethyan eustatic cycles are evidenced and may have had considerable impact on prominent middle Carnian events: Reingraben turnover, Carnian Pluvial Event, Carnian Crisis and Mid Carnian Wet Intermezzo. The broad circum-Tethyan evidence of 106-year scale cycles suggests glacioeustatic sea-level changes even in the Triassic Greenhouse period.

  12. Late Quaternary river incision rate from L'Aquila-Scoppito Basin (central Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Nocentini, Marco; Tallini, Marco; Asti, Riccardo; Cosentino, Domenico

    2014-05-01

    L'Aquila-Scoppito Basin (ASB) is part of the wider L'Aquila Basin, one of the most tectonically active intermontane basins of central Apennines (Italy). ASB is a semi-enclosed intermontane sedimentary basin of morphotectonic origin, W-E trending and approximately 20 km2 wide, with mean elevations ranging between 850 and 650 m a.s.l. and it is crossed by two main water courses: the Aterno River and the Raio Creek. Structurally, the ASB may be considered as an half-graben, bordered northerly by the south-dipping Scoppito-Preturo normal Fault and easterly by the southwest dipping Pettino Fault. In the L'Aquila-Scoppito Basin a series of erosional and depositional post Middle Pleistocene events generated three order of fluvial terraces, generally not completely preserved. The first order of fluvial terrace, the Vetoio Synthem (T1), is a fill terrace carved into both the L'Aquila Breccia Synthem (Middle Pleistocene) and the Madonna della Strada Synthem (Lower Pleistocene), whose top is preserved near the L'Aquila airport and the S. Salvatore hospital, approximately at 20-25 m above the present thalweg of the Aterno River. The second order of terrace, the Pile Synthem (T2), is a strath terrace embedded into T1 and carved into both the Lower Pleistocene deposits and the pre-Quaternary bedrock. The top of T2 is located at 10-13 m above the present thalweg of the Raio Creek. Charcoaled plant remains founded within the sandy layers of T2 give a 14C 2σ age of 41854-40464 BP (MIS 3). This age is in agreement with traces of lithic industry of Mousterian age (late Middle Paleolithic) inside the gravels. The youngest order of terrace, Ponte Peschio Synthem (T3), lies 5-7 m above both the Raio and the Aterno thalwegs. T3 is embedded into T1 and carved in the L'Aquila Breccia Synthem, near the S. Salvatore hospital, while at Ponte Peschio it is embedded into T2 and is carved directly into the pre-Quaternary bedrock. Then, also T3 may be interpreted as a strath terrace. River

  13. The unconventional hydrocarbon potential in the central part of the Baltic Basin

    NASA Astrophysics Data System (ADS)

    Lazauskiene, Jurga; Zdanaviciute, Onyte

    2014-05-01

    The Baltic Basin is an intracratonic Phanerozoic sedimentary basin, situated on the Western margin of the East European Craton. The unconventional hydrocarbon potential is mostly related to the several organic-rich source rock complexes within the Early Palaeozoic section. In the south-eastern part of the Baltic Basin the Cambrian shales (Alum shales and Middle Cambrian), Ordovician black shales of the Caradocian age and Silurian Llandovery shales are considered as the major potential shale oil/gas playes. The depth of the the base of the Silurian shales varies from 2120 to 1125 m in the Lithuanian part of the basin. The thickness of the Lower Silurian shales in - varies from 110m to160 m. The organic matter of the source rocks is of similar composition - predominantly "oil-producing" sapropel (type II) and mixed "oil-gas liquids producing" type II-III. Pyrolisis yields (32 - 76(~100) kg HC/ton rock) suggests a good hydroacarbon generation potential. Total organic carbon content varies from 0.2-3 to 8-11%. Maximal values of the total organic carbon (up to 17%) have been recorded near the base of the Silurian (2-11 m Middle Llandovery interval) and its content generally decreases upwards the section. The Rock-Eval screening pyrolysis, biomarker data, reflectance of vitrinite-like macerals and conodont colour alteration index show considerable variations of the source rocks maturity through the basin. Maturity of the organic matter increases southwestwards from 0.6 up to 1.94% (Ro). Thermal maturity in this area ranges from immature in the Eastern part of Lithuania and to "oil window" in the Western Lithuania. In some places in central part of the basin (wells Ramučiai-1, Pajūris-1 and others) the anomalously high maturity of organic matter, indicating the lower part of the wet gas/condensate window have been recorded, most probably being related to the locally increased paleo-temperatures. Llandovery shales are clay-rich, an average values range from 28-59vol

  14. Ethiopian Central Rift Valley basin hydrologic modelling using HEC-HMS and ArcSWAT

    NASA Astrophysics Data System (ADS)

    Pascual-Ferrer, Jordi; Candela, Lucila; Pérez-Foguet, Agustí

    2013-04-01

    An Integrated Water Resources Management (IWRM) shall be applied to achieve a sustainable development, to increase population incomes without affecting lives of those who are highly dependent on the environment. First step should be to understand water dynamics at basin level, starting by modeling the basin water resources. For model implementation, a large number of data and parameters are required, but those are not always available, especially in some developing countries where different sources may have different data, there is lack of information on data collection, etc. The Ethiopian Central Rift Valley (CRV) is an endorheic basin covering an area of approximately 10,000 km2. For the period 1996-2005, the average annual volume of rainfall accounted for 9.1 Mm3, and evapotranspiration for 8 Mm3 (Jansen et al., 2007). From the environmental point of view, basin ecosystems are endangered due to human activities. Also, poverty is widespread all over the basin, with population mainly living from agriculture on a subsistence economy. Hence, there is an urgent need to set an IWRM, but datasets required for water dynamics simulation are not too reliable. In order to reduce uncertainty of numerical simulation, two semi-distributed open software hydrologic models were implemented: HEC-HMS and ArcSWAT. HEC-HMS was developed by the United States Army Corps of Engineers (USACoE) Hydrologic Engineering Center (HEC) to run precipitation-runoff simulations for a variety of applications in dendritic watershed systems. ArcSWAT includes the SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) model developed for the USDA Agricultural Research Service into ArcGIS (ESRI®). SWAT was developed to assess the impact of land management practices on large complex watersheds with varying soils, land use and management conditions over long periods of time (Neitsch et al., 2005). According to this, ArcSWAT would be the best option for IWRM implementation in the basin. However

  15. Analysis of Proterozoic rifting and subsequent subsidence of the Central Congo Basin

    NASA Astrophysics Data System (ADS)

    Kadima Kabongo, Etienne; Sebagenzi Mwene Ntabwoba, Stanislas; Lucazeau, Francis

    2010-05-01

    The Central Basin (or Cuvette Centrale) of Congo is a late-Proterozoic to Recent basin covering near one million km2 with up to 9 km of sediment. Its subsidence has been related to a preexisting failed rift (Daly et al, 1992), whose origin, geometry and structure remain largely unknown. Here we present a combined analysis of subsidence and gravity that provides new lines of evidence for a rift origin. Although the dataset for the Central Basin is poor and has not been improved for a long time (only four deep wells with depths between 1856 and 4666 meters and 33 seismic lines covering 2900 km), it is sufficient for the first order characteristics. The analysis of wells data reveals that the long term subsidence (~450 m.y.) and present-day surface heat flow (~40 mWm-2) are both characteristic of a 250 km thick thermal lithosphere. This is consistent with the Archean age of the craton but not with thermal reworking during Paleozoic as hypothesized by Artemieva (2006). From the seismic lines, we can derive a 3D geometrical basin model divided into three different units defined by two major uncomformities. Each layer is assigned an average density value inferred from geophysical logs and then gravity effect is determined and subtracted from the observed gravity anomalies. The residual map shows a positive SE-NW elongated structure that can be related to a possible rift prior to basin subsidence. In order to determine the associated crustal structure, we simply assumed that the post-rift subsidence is flexural and that the rift isostasy is governed by a depth of necking. The procedure involves first flexural backstripping of sediments assuming a given Equivalent Elastic Thickness EET and then determination of the crustal thickness assuming a given depth of necking DON. EET and DON are varied in order to obtain the minimum misfit between predicted and observed gravity. The best results are obtained for EET = 100 km, DON = 10 km and an initial crust thickness of 35 km. The

  16. Central Appalachian basin natural gas database: distribution, composition, and origin of natural gases

    USGS Publications Warehouse

    Román Colón, Yomayra A.; Ruppert, Leslie F.

    2015-01-01

    The U.S. Geological Survey (USGS) has compiled a database consisting of three worksheets of central Appalachian basin natural gas analyses and isotopic compositions from published and unpublished sources of 1,282 gas samples from Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The database includes field and reservoir names, well and State identification number, selected geologic reservoir properties, and the composition of natural gases (methane; ethane; propane; butane, iso-butane [i-butane]; normal butane [n-butane]; iso-pentane [i-pentane]; normal pentane [n-pentane]; cyclohexane, and hexanes). In the first worksheet, location and American Petroleum Institute (API) numbers from public or published sources are provided for 1,231 of the 1,282 gas samples. A second worksheet of 186 gas samples was compiled from published sources and augmented with public location information and contains carbon, hydrogen, and nitrogen isotopic measurements of natural gas. The third worksheet is a key for all abbreviations in the database. The database can be used to better constrain the stratigraphic distribution, composition, and origin of natural gas in the central Appalachian basin.

  17. Cryogenian Interglacial Litho- and C Isotope Chemo-stratigraphy of the Amadeus Basin, Central Australia

    NASA Astrophysics Data System (ADS)

    Verdel, C.; Campbell, M.; Phelps, B.

    2015-12-01

    The Cryogenian stratigraphy of the Amadeus Basin in central Australia consists of the Areyonga, Aralka, and Olympic Formations. Both the Areyonga and Olympic Fms. include glacial deposits overlain by cap carbonates, observations that have prompted correlation of these formations with the global Sturtian and Marinoan glaciations, respectively. In this study we focus on the interglacial stratigraphic unit (Aralka Fm.), which is subdivided into the lower Ringwood Mbr. and the upper Limbla Mbr. C isotope values from carbonates within the Limbla Mbr. are particularly large (up to +10 per mil), suggesting that it correlates with the global "Keele Peak" anomaly. The underlying Ringwood Mbr. (the base of which comprises the Sturtian cap carbonate of the Amadeus Basin) varies from thin or non-existent in the northwestern part of the basin to hundreds of meters thick in eastern parts. C isotope values from Ringwood Mbr. carbonates are roughly -5 per mil at its base and rise rapidly up-section. A mid-interglacial negative C isotope excursion to values of approximately -5 per mil in the Ringwood Mbr. may correlate with the Tayshir anomaly of the Mongolian Neoproterozoic succession. Interglacial carbonates of the Aralka Fm. therefore have C isotope compositions that span at least 15 per mil and include both positive and negative isotopic excursions that seem to be globally correlative. Furthermore, detailed field observations from the Ringwood Mbr. suggest that it can be subdivided into three submembers, each of which is marked by stromatolitic intervals. Shallowing-upward parasequences in the Ringwood Mbr., as well as a major change in lithology from siltstones and microbialites of the Ringwood Mbr. to dominantly coarse-grained, cross-stratified sandstones of the Limbla Mbr., suggest that the interglacial strata of the Amadeus Basin were deposited during a period of significant and repeated changes in relative sealevel.

  18. A seismic refraction and reflection study across the central San Jacinto Basin, Southern California

    USGS Publications Warehouse

    Lee, T.-C.; Biehler, S.; Park, S.K.; Stephenson, W.J.

    1996-01-01

    The San Jacinto Basin is a northwest-trending, pullapart basin in the San Jacinto fault zone of the San Andreas fault system in southern California. About 24 km long and 2 to 4 km wide, the basin sits on a graben bounded by two strands of the San Jacinto fault zone: the Claremont Fault on the northeast and the Casa Loma Fault on the southwest. We present a case study of shallow structure (less than 1 km) in the central basin. A 2.75-km refraction line running from the northeast to southwest across the regional structural trend reveals a groundwater barrier (Offset I). Another line, bent southward and continued for 1.65-km, shows a crystalline basement offset (Offset III) near an inferred trace of the Casa Loma Fault. Although a basement refractor was not observed along the 2.75-km line, a mismatch between the estimate of its minimum depth and the basement depth determined for the 1.65-km line suggests that an offset in the basement (greater than 260 m) exists around the junction of the two refraction lines (Offset II). By revealing more faults and subtle sedimentary structures, the reflection stack sections confirm the two refraction offsets as faults. Offsets I and III each separate sediments of contrasting structures and, in addition. Offset III disrupts an unconformity. However, the sense and amount of the offset across Offset III contradict what may be expected across the Casa Loma Fault, which has its basinward basement down-thrown to about 2.5 km in the better defined southeastern part of the graben. The Casa Loma Fault trace has been mislinked in the existing geological maps and the trace should be remapped to Offset II where the reflector disruptions spread over a 400-m wide zone. Our Offset III is an unnamed, concealed fault.

  19. Petroleum exploration of Winnipegosis Formation in north-central North Dakota (Williston basin)

    SciTech Connect

    Guy, W.J. Jr.; Braden, K.W.

    1986-08-01

    The Winnipegosis Formation (Middle Devonian) in north-central Dakota has the greatest potential for large oil reserves in the Williston basin. The Winnipegosis carbonate (50 to 325 ft thick) was deposited in the southeast end of the Elk Point restricted sea. During Winnipegosis deposition, the Williston basin could be divided into two distinct environments: (1) a deep starved basin with accompanying pinnacle reefs separated by interreef, laminated limestone and (2) a surrounding carbonate shelf. Within the carbonate shelf are patch reefs, banks, and tidal flats. Overlying the Winnipegosis carbonate is the Prairie Formation, which has a basal anhydrite (0 to 70 ft thick) and an overlying salt (0 to 650 ft thick). These were deposited in a regressive phase of the Elk Point sea and act as seals for Winnipegosis oil entrapment. Currently, oil production from the Winnipegosis in the Williston basin is from stratigraphic traps and from small structures on the carbonate shelf. The most significant accumulation to date is Temple field, in which 11 wells produce from +/- 20 ft of Winnipegosis dolomite. The pinnacle reef environment has potential for significant oil reserves from 250-ft thick reefs covering 160 ac or less. Two pinnacle reefs have had free-oil recoveries from thin pay zones. The Rainbow/Zama fields in northwest Alberta have an ultimate reserve of more than 1 billion bbl of oil from Keg River reefs, which are correlative and similar to the Winnipegosis reefs in North Dakota. The strong seismic reflection that originates from the Winnipegosis-Prairie evaporite interface provides an excellent means of detecting Winnipegosis reefs. Amplitude of the Winnipegosis reflection is reduced dramatically over the reefs. The resulting dim spot is one criteria used in identifying reefs.

  20. Estimates of ground-water recharge rates for two small basins in central Nevada

    SciTech Connect

    Lichty, R.W.; McKinley, P.W.

    1995-11-01

    Estimates of ground-water recharge rates developed from hydrologic modeling studies are presented for 3-Springs and East Stewart basins, two small basins (analog sites) located in central Nevada. The analog-site studies were conducted to aid in the estimation of recharge to the paleohydrologic regime associated with ground water in the vicinity of Yucca Mountain under wetter climatic conditions. The two analog sites are located to the north and at higher elevations than Yucca Mountain, and the prevailing (current) climatic conditions at these sites is thought to be representative of the possible range of paleoclimatic conditions in the general area of Yucca Mountain during the Quaternary. Two independent modeling approaches were conducted at each of the analog sites using observed hydrologic data on precipitation, temperature, solar radiation, stream discharge, and chloride-ion water chemistry for a 6-year study period (October 1986 through September 1992). Both models quantify the hydrologic water-balance equation and yield estimates of ground-water recharge, given appropriate input data. Results of the modeling approaches support the conclusion that reasonable estimates of average-annual recharge to ground water range from about 1 to 3 centimeters per year for 3-Springs basin (the drier site), and from about 30 to 32 centimeters per year for East Stewart basin (the wetter site). The most reliable results are those derived from a reduced form of the chloride-ion model because they reflect integrated, basinwide processes in terms of only three measured variables: precipitation amount, precipitation chemistry, and streamflow chemistry.

  1. Minibasins and salt canopy in foreland fold-and-thrust belts: The central Sivas Basin, Turkey

    NASA Astrophysics Data System (ADS)

    Kergaravat, Charlie; Ribes, Charlotte; Legeay, Etienne; Callot, Jean-Paul; Kavak, Kaan Sevki; Ringenbach, Jean-Claude

    2016-06-01

    The Sivas Basin in the Central Anatolian Plateau (Turkey), which formed in the context of a foreland fold-and-thrust belt (FTB), exhibits a typical wall and basin (WAB) province characterized by symmetric minibasins separated by continuous steep-flanked walls and diapirs. Extensive fieldwork including regional and detailed local mapping of the contacts and margins of minibasins, and interpretation of a set of 2-D regional seismic lines, provide evidence for the development of a shallow evaporite level separating two generations of minibasins within the WAB province. Here beds of symmetric exposed minibasins along diapir flank are younger than minibasins observed over autochthonous evaporites. Laterally away from the WAB province, increase in wavelength of the tectonic structures suggests a deepening of the decollement level. We interpret that a shallower evaporite level developed in the form of an evaporite canopy, triggered by significant lateral shortening. The Upper Eocene-Lower Oligocene autochthonous Tuzhisar evaporite level was remobilized by the northward migrating sedimentary load and the tilting of the southern basin margin during propagation of the foreland fold-and-thrust belt. Asymmetric and symmetric primary minibasins were overrun by an allochthonous sheet forming a canopy. A second generation of salt withdrawal minibasins subsided into the allochthonous salt sheet. The polygonal pattern of the WAB province influences the growing fold-and-thrust belt system during the late stage of the secondary minibasins development. The Sivas FTB basin is the result of the interaction between fold-and-thrust belt propagation, evaporite remobilization, and interaction between evaporite flow and sedimentation in the minibasins.

  2. Polyphase tectonic subsidence evolution of the Vienna Basin inferred from quantitative subsidence analysis of the northern and central parts

    NASA Astrophysics Data System (ADS)

    Lee, Eun Young; Wagreich, Michael

    2016-04-01

    The Vienna Basin is a tectonically complex Neogene basin situated at the Alpine-Carpathian transition. This study analyzes a detailed quantification of subsidence in the northern and central parts of the Vienna Basin to understand its tectonic subsidence evolution. About 200 wells were used to arrange stratigraphic setting, and wells reaching the pre-Neogene basement were analyzed for subsidence. To enhance the understanding of the regional subsidences, the wells were sorted into ten groups based on their position on major fault blocks. In the Early Miocene, subsidence was slow and along E-W to NE-SW trending axis, indicating the development of thrust-controlled piggyback basins. During the late Early Miocene data show abruptly increasing subsidence, making the initiation of the Vienna pull-apart basin system. From the Middle Miocene, the tectonic subsidence curves show regionally different patterns. The tectonic subsidence during the Middle Miocene varies laterally across the Vienna Basin, and the differential subsidence can be related to the changing tensional regime of weakening transtension and strengthening extension toward the late Middle Miocene. From the late Middle Miocene to the Late Miocene, the tectonic subsidence occurred dominantly along the regional active faults, and corresponds to the axis of E-W trending extension of the western parts of the Pannonian Basin system. In the Quaternary the Vienna Basin has been reactivated, and resulted in subsidence along the NE-SW trending Vienna Basin transfer fault system.

  3. Cretaceous stratigraphic sequences of north-central California suggest a discontinuity in the Late Cretaceous forearc basin

    SciTech Connect

    Haggart, J.W.

    1986-10-01

    The Cretaceous sedimentary succession preserved east of Redding, at the northern end of California's Great Valley, indicates that marine deposition was widespread in the region for only two periods during the Late Cretaceous. If it is assumed that there was minimal Cenozoic offset between the northern Sierra Nevada and eastern Klamath Mountains terranes, Cretaceous sedimentation in this region was most likely restricted to a narrow trough and was not a continuation of the wide, Cretaceous forearc basin of central California. The dissimilar depositional histories of the Redding basin and the Hornbrook basin of north-central California suggest that the basins were not linked continuously during the Late Cretaceous. A thick section of Cretaceous strata beneath the southwestern Modoc Plateau is considered unlikely.

  4. Evidence for formation of a flexural backarc basin by compression and crustal thickening in the central Alaska peninsula

    SciTech Connect

    Bond, G.C.; Lewis, S.D.; Taber, J.; Steckler, M.S.; Kominz, M.A. )

    1988-12-01

    The North Aleutian Basin is a large, Cenozoic sedimentary basin in the northern part of the central Alaska Peninsula and the southern Bering shelf. The gravity anomaly pattern, the geometry, and the structure of the basin suggest that if formed by downward flexure of the backarc lithosphere. Basin modeling suggests that the flexure was driven by the emplacement of surface and subsurface loads having densities comparable to those of oceanic crust and mantle rocks, at approximately the position of the present-day volcanic arc and forearc. The authors suggest that the inferred loads consist of tectonically thickened mafic crustal materials lying beneath the arc and forearc of the central Alaska Peninsula. The crustal thickening may have occurred within a dominantly transpressional regime resulting from oblique convergence between the North American and Pacific plates during the Cenozoic.

  5. Estimation of evapotranspiration in the Rainbow Springs and Silver Springs basins in North-Central Florida

    USGS Publications Warehouse

    Knowles, Leel, Jr.

    1996-01-01

    Estimates of evapotranspiration (ET) for the Rainbow and Silver Springs ground-water basins in north-central Florida were determined using a regional water-~budget approach and compared to estimates computed using a modified Priestley-Taylor (PT) model calibrated with eddy-correlation data. Eddy-correlation measurements of latent 0~E) and sensible (H) heat flux were made monthly for a few days at a time, and the PT model was used to estimate 3,E between times of measurement during the 1994 water year. A water-budget analysis for the two-basin area indicated that over a 30-year period (196594) annual rainfall was 51.7 inches. Of the annual rainfall, ET accounted for about 37.9 inches; springflow accounted for 13.1 inches; and the remaining 0.7 inch was accounted for by stream-flow, by ground-water withdrawals from the Floridan aquifer system, and by net change in storage. For the same 30-year period, the annual estimate of ET for the Silver Springs basin was 37.6 inches and was 38.5 inches for the Rainbow Springs basin. Wet- and dry-season estimates of ET for each basin averaged between nearly 19 inches and 20 inches, indicating that like rainfall, ET rates during the 4-month wet season were about twice the ET rates during the 8-month dry season. Wet-season estimates of ET for the Rainbow Springs and Silver Springs basins decreased 2.7 inches, and 3.4 inches, respectively, over the 30-year period; whereas, dry-season estimates for the basins decreased about 0.4 inch and1.0 inch, respectively, over the 30-year period. This decrease probably is related to the general decrease in annual rainfall and reduction in net radiation over the basins during the 30-year period. ET rates computed using the modified PT model were compared to rates computed from the water budget for the 1994 water year. Annual ET, computed using the PT model, was 32.0 inches, nearly equal to the ET water-budget estimate of 31.7 inches computed for the Rainbow Springs and Silver Springs basins

  6. Groundwater quality in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts, 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. Selected groundwater basins in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts constitute one of the study units being evaluated.

  7. Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

    SciTech Connect

    Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby

    2006-02-28

    The principal research effort for Year 3 of the project is basin modeling and petroleum system identification, comparative basin evaluation and resource assessment. In the first six (6) months of Year 3, the research focus is on basin modeling and petroleum system identification and the remainder of the year the emphasis is on the comparative basin evaluation and resource assessment. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.

  8. 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

  9. Surface uplift and convective rainfall along the southern Central Andes (Angastaco Basin, NW Argentina)

    NASA Astrophysics Data System (ADS)

    Pingel, Heiko; Mulch, Andreas; Alonso, Ricardo N.; Cottle, John; Hynek, Scott A.; Poletti, Jacob; Rohrmann, Alexander; Schmitt, Axel K.; Stockli, Daniel F.; Strecker, Manfred R.

    2016-04-01

    Stable-isotopic and sedimentary records from the orogenic Puna Plateau of NW Argentina and adjacent intermontane basins to the east furnish a unique late Cenozoic record of range uplift and ensuing paleoenvironmental change in the south-central Andes. Today, focused precipitation in this region occurs along the eastern, windward flanks of the Eastern Cordillera and Sierras Pampeanas ranges, while the orogen interior constitutes high-elevation regions with increasingly arid conditions in a westward direction. As in many mountain belts, such hydrologic and topographic gradients are commonly mirrored by a systematic relationship between the oxygen and hydrogen stable isotope ratios of meteoric water and elevation. The glass fraction of isotopically datable volcanic ash intercalated in sedimentary sequences constitutes an environmental proxy that retains a signal of the hydrogen-isotopic composition of ancient precipitation. This isotopic composition thus helps to elucidate the combined climatic and tectonic processes associated with topographic growth, which ultimately controls the spatial patterns of precipitation in mountain belts. However, between 25.5 and 27°S present-day river-based hydrogen-isotope lapse rates are very low, possibly due to deep-convective seasonal storms that dominate runoff. If not accounted for, the effects of such conditions on moisture availability in the past may lead to misinterpretations of proxy-records of rainfall. Here, we present hydrogen-isotope data of volcanic glass (δDg), extracted from 34 volcanic ash layers in different sedimentary basins of the Eastern Cordillera and the Sierras Pampeanas. Combined with previously published δDg records and our refined U-Pb and (U-Th)/He zircon geochronology on 17 tuff samples, we demonstrate hydrogen-isotope variations associated with paleoenvironmental change in the Angastaco Basin, which evolved from a contiguous foreland to a fault-bounded intermontane basin during the late Mio

  10. Ophiolite suture in Central Anatolia: New insights from the Sivas Basin (Turkey)

    NASA Astrophysics Data System (ADS)

    Legeay, Etienne; Ringenbach, Jean-Claude; Mohn, Geoffroy; Kergaravat, Charlie; Callot, Jean-Paul

    2015-04-01

    The closure of the Neotethys is classically associated with the obduction of ophiolitic rocks, defining successive suture zones. Theses Alpine-Himalayan ophiolites reflect a complex and still poorly understood paleogeographic framework. In Turkey, various types of ophiolite have been described, involving supra subduction zone and ophiolitic melanges as well. Hence reconstructions of the Anatolian continent assumed the amalgamation of one or more continental fragments during the Mesozoic-Early Cenozoic time. The Sivas Basin is located in a key position at the junction of three crustal domains: the Pontides to the North, the Anatolide - Tauride platforms to the South, and the Central Anatolian Crystalline Complex to the West. These blocks are separated to the North by the Izmir-Ankara-Erzican suture zone (IAESZ), and by the Inner Tauride suture zone (ITSZ) to the South. Ophiolitic outcrops are common in this area, mainly on the basin borders, and sometimes within the central part. These green rocks have been previously related to the ophiolitic melange from the IAESZ in Northern part and to the ITSZ for the southern parts. Recent fieldwork on the southern edge of the Sivas Basin allows a proper description of the ophiolitic complex, including from bottom to top: (1) a large volume of intensely serpentinized peridotites, strongly veined with chrysotile, with minor gabbroic intrusions; (2) upward, serpentinized mantle rocks affected by a cataclastic deformation associated with tectonic breccias and ophicalcites ; and eventually, (3) on the top of the mantle, silicates deposits similar to radiolarian cherts cover by sedimentary breccias with mantle clasts. New geochemical analysis and subsurface data confirm the existence of a southward obducted slice of ophiolite over more than 100km from North to South, forming the basement of the Sivas Basin since the Campanian. This southward obduction related to the IAESZ appears similar to slow spreading ridge or hyper

  11. Deglaciation of the Central Lake Superior Basin Imaged by High-Resolution Seismic-Reflection Profiles

    NASA Astrophysics Data System (ADS)

    Colman, S. M.; Breckenridge, A. J.; Wattrus, N. J.

    2015-12-01

    The Lake Superior basin experienced multiple episodes of glaciation, resulting in a variety of glacial deposits and landforms, most of which date to the final retreat of Laurentide ice from the basin. Prominent among these features are moraines and thick glacial lacustrine varve sequences in the central part of the lake. Because these features are now beneath deep water, they can be well imaged by modern marine seismic-reflection methods, providing a variety of insights into glacial processes and history. Two prominent moraines occur east of Isle Royale, and other morainal deposits exist. The prominent moraines are as much as 75 m high, asymmetric, and locally concave down-ice in plan view. They are steeper up-ice than down, but vary in morphology along strike. Air-gun seismic-reflection data show that the moraines are underlain by thick, acoustically massive deposits (till) over a smooth bedrock surface, and that, in front of the moraines, the till grades laterally into increasingly stratified deposits interpreted as glacial lacustrine outwash. Such lateral relations between till and outwash are rarely displayed so well in natural exposures. The moraines relate to the Marquette advance of the Laurentide ice sheet, but they are difficult to directly correlate with the terrestrial deposits used to define that advance. Overlying the till and moraines is a thick sequence of glacial lacustrine varves, which are well imaged by high-resolution CHIRP seismic-reflection profiles. Although the CHIRP data cannot resolve even the thickest of the individual varves, the section comprises distinct acoustic packages. The CHIRP data show that the base of the varve sequence becomes younger to the northeast, the direction of ice retreat. Throughout the varved sequence are lenses of acoustically massive material and local features interpreted as iceberg plow marks, which are especially concentrated at one horizon. Limited 3-D seismic data show the curvilinear plan view of the plough

  12. The evolution of the Thuringian Syncline (Central Germany) - an interdisciplinary approach to basin reconstruction

    NASA Astrophysics Data System (ADS)

    Malz, Alexander; Beyer, Daniel; Donndorf, Stephan; Navabpour, Payman; Voigt, Thomas; Aehnelt, Michaela; Kley, Jonas

    2014-05-01

    The Thuringian Syncline is a shallow synform of mainly Triassic strata in Central Germany. In general, its lithostratigraphic units are similar to that of the North German Basin. On the top of the Paleozoic basement and Permocarboniferous red beds the evaporites of the late Permian Zechstein were deposited. The Triassic super group consists of fluvial to lacustrine sandstones, shale and evaporites of the Buntsandstein group, limestone, marls and evaporites of the marine Muschelkalk group and pelitic to sandy fluvial deposits and evaporite of the Keuper group. Some relicts of Lower Jurassic deposits still cover this succession. A number of NW-SE-trending fault zones with mostly small normal offsets characterize the recent structural configuration of the Thuringian Syncline. From regional correlations, and Lower Jurassic strata affected by normal faults, the extension most likely occurred in Late Jurassic to Early Cretaceous time. Some of these normal faults were reactivated as reverse faults during a phase of contraction in the Late Cretaceous. The unknown original offsets of the normal faults and the absence of syntectonic strata deposited during extension and contraction, however, make reconstruction of the graben inversion difficult to detect. In this study we try to reconstruct the structural evolution of the Thuringian Syncline based on structural observations, detailed map analysis, interpolations of stratigraphic surfaces at depth, cross section balancing and fault slip data analysis. Vitrinite reflectance data are used to estimate the maximum thickness of the eroded overburden. Our study identified a deep, extended and later inverted palaeo-depression in the central part of the Thuringian Syncline. We show that the recent structural configuration cannot explain variations of the thermal maturity without deriving specific thickness variations in the eroded overburden. Taking in consideration that many Central European faults, formerly interpreted as purely

  13. Paleobathymetric maps of tertiary La Honda Basin and implications for offset along San Andreas fault in central California

    SciTech Connect

    Stanley, R.G.

    1987-05-01

    Paleobathymetric maps of the La Honda basin of central California were constructed for ten intervals of geologic time from late Paleocene (Nezian) to middle Miocene (Luisian). The maps are based on analyses of benthic foraminiferal biofacies in more than 800 faunal lists compiled from the literature and from subsurface data provided by oil companies. The sequence of paleobathymetric maps shows the paleogeographic evolution of the La Honda basin. From the late Paleocene (Ynezian) to the early Oligocene (early Zemorrian), deep-sea sands and muds accumulated at water depths of 2000 m and more on a surface that sloped gently to the north and northeast. Striking changes in the configuration of the La Honda basin occurred during the late Oligocene and early Miocene (late Zemorrian). Much of the basin floor remained at water depths of 2000 m and greater, but submarine volcanic rocks locally built up to form seamounts, and movement along the Zayante-Vergeles fault led to shoaling and development of a narrow shelf and very steep slope along the southwestern margin of the basin. During the early and middle Miocene (Relizian and Luisian), the entire basin shoaled to depths of less than 1500 m. Comparison of paleobathymetric maps of the La Honda and San Joaquin basins lends support to the notion that the two basins were once contiguous but have been separated by about 320 to 330 km of right-lateral displacement along the San Andreas fault since the earliest Miocene (late Zemorrian and Saucesian).

  14. 17. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

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

    17. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 Elevations - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

  15. 14. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

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

    14. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, N&, 1934 Foundation Plan - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

  16. 18. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

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

    18. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 Detail sheet - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

  17. 15. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

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

    15. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 First Floor - plumbing - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

  18. 16 Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

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

    16 Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers Murray, and Phillip, Architects, New York, NY, 1934 first floor mechanical plan - heating - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

  19. Dissolved organic matter and terrestrial-lotic linkages in the Central Amazon Basin of Brazil

    NASA Astrophysics Data System (ADS)

    McClain, Michael E.; Richey, Jeffrey E.; Brandes, Jay A.; Pimentel, Tania P.

    1997-09-01

    We evaluate the hypothesis that decomposition and adsorption reactions operating in upland soils of headwater catchments control the concentration and composition of dissolved and fine particulate organic matter in rivers of the Amazon basin. In two contrasting first-order catchments characteristic of the central Amazon basin, we analyzed plant, litter, soil, groundwater, and stream water chemistry. Our results indicate that clear and persistent differences exist in the concentration and elemental composition of dissolved organic matter (DOM) in stream waters and groundwaters from the two catchments, due mainly to corresponding differences in soil texture and chemistry. Within the more oxide and clay rich Oxisols underlying terra firme forest, groundwater DOM concentrations were uniformly low (120 μMC) and C/N ratios averaged 10. Conversely, within the oxide and clay deficient Spodosols underlying campinarana forest, groundwater DOM concentrations were greatly elevated (3000 μMC), and C/N ratios averaged near 60. We found that, in the terra firme/Oxisol terrain, the majority of DOM contributions to the stream derived from the riparian zone, while in the campinarana/Spodosol terrain, upland groundwater contributions could account for the concentration and composition of DOM in the stream. The implications of our findings are that in the terra firme terrains which dominate the region, upland soil profiles are not the site of definitive processes which impart compositional signatures to organic matter carried by the largest rivers of the Amazon basin, as was hypothesized. Instead, we suggest that definitive reactions are focused primarily in the river corridor.

  20. Apatite fission-track thermochronology of the central and southern Appalachian Basin

    SciTech Connect

    Roden, M.K.

    1989-01-01

    Samples were collected in west to east transects across the Appalachian Basin of Pennsylvania, Maryland, West Virginia, and Virginia. These samples locations were chosen to test the concept of increasing paleotemperature due to increasing burial from west to east across the Appalachian Basin and to detect any thermal anomalies that exist. Calculated time-temperature (tT) paths based on apatite fission-track apparent ages and confined track length distributions for samples from this study indicate that both the Pennsylvania and southern Appalachian had complex uplift and cooling histories. In Pennsylvania, the Tioga and Kalkberg ash bed samples from central Pennsylvania yield modelled tT paths that indicate early post-Alleghanian (285-270 Ma) cooling with uplift estimated at beginning at {approx}251 {plus minus} 25 Ma. Samples from the western Allegheny Plateau and Allegheny Front contain apatites which have reset to give fission-track ages and track lengths consistent with tT histories beginning at <200 Ma. In northeastern Pennsylvania on the Allegheny Plateau, the modelled tT paths show rapid cooling from temperatures in the range of 110{degree}-120{degree} C at 170-160 Ma. In the southern Appalachian Basin, calculated tT paths indicate that uplift in the northern section was immediately post-Alleghanian folding with uplift beginning first in the northwestern section on the Cumberland Plateau at {approx}226 {plus minus} 23 Ma and progressing to the eastern Valley and Ridge Province of Virginia at {approx}119 {plus minus} 12 Ma. The samples from southwestern Virginia yield a mean apatite fission-track apparent age of 175 {plus minus} 11 Ma which may be the result of a higher heat flow, higher paleogeothermal gradient during the Upper Jurassic-Early Cretaceous extension along the Atlantic Coast.

  1. Late Quaternary Alluvial Fans and Beach Ridge Systems in Jakes Valley, Central Great Basin, USA

    NASA Astrophysics Data System (ADS)

    Garcia, A. F.; Stokes, M.; Benitez, L.

    2002-12-01

    Alluvial fan and lake beach ridge landforms provide archives of the geomorphic response to Late Quaternary climate change within the Great Basin region. This study presents the first detailed results of landform mapping and soil characterization from Jakes Valley, a high altitude (1920m) and internally drained basin, located within a previously unstudied part of White Pine County, East-Central Nevada. Mountain front alluvial fans sourced from the White Pine and Egan Ranges (west-east basin margins) are characterized by four morphostratigraphic units: Qf0 (oldest) through to Qf3 (youngest). Analysis of the soil properties of these stratigraphic units reveals two landform-soil assemblages: 1) Qf0-1, characterized by well-developed calcic soils (stages III+ to IV) and 2) Qf2-3, characterized by less well-developed calcic soils (stages I to II). Beach ridge systems formed during pluvial lake highstands are extensively developed into the mid and distal parts of alluvial fans. Integrated field and aerial photograph mapping has revealed a sequence of between 4-6 ridges with linear and / or highly curved / arcuate morphologies. Beach ridge soil properties are characterized by less well-developed calcic soils (stages I+ to II) that are similar to soils formed in Qf2 alluvial fan units. The interaction between the alluvial fan and beach ridge landforms can be utilized to explore the geomorphic response in relation to climatic amelioration during the Late Pleistocene-Holocene transition. Of particular interest is the common occurrence of the curved / arcuate beach ridges which may correspond to a period of fan progradation coincident with base-level lowering.

  2. Neogene paleoelevation of intermontane basins in a narrow, compressional mountain range, southern Central Andes of Argentina

    NASA Astrophysics Data System (ADS)

    Hoke, Gregory D.; Giambiagi, Laura B.; Garzione, Carmala N.; Mahoney, J. Brian; Strecker, Manfred R.

    2014-11-01

    The topographic growth of mountain ranges at convergent margins results from the complex interaction between the motion of lithospheric plates, crustal shortening, rock uplift and exhumation. Constraints on the timing and magnitude of elevation change gleaned from isotopic archives preserved in sedimentary sequences provide insight into how these processes interact over different timescales to create topography and potentially decipher the impact of topography on atmospheric circulation and superposed exhumation. This study uses stable isotope data from pedogenic carbonates collected from seven different stratigraphic sections spanning different tectonic and topographic positions in the range today, to examine the middle to late Miocene history of elevation change in the central Andes thrust belt, which is located immediately to the south of the Altiplano-Puna Plateau, the world's second largest orogenic plateau. Paleoelevations are calculated using previously published local isotope-elevation gradients observed in modern rainfall and carbonate-formation temperatures determined from clumped isotope studies in modern soils. Calculated Neogene basin paleoelevations are between 1 km and 1.9 km for basins that today are located between 1500 and 3400 m elevation. Considering the modern elevation and δ18O values of precipitation at the sampling sites, three of the intermontane basins experienced surface uplift between the end of deposition during the late Miocene and present. The timing of elevation change cannot be linked to any documented episodes of large-magnitude crustal shortening. Paradoxically, the maximum inferred surface uplift in the core of the range is greatest where the crust is thinnest. The spatial pattern of surface uplift is best explained by eastward migration of a crustal root via ductile deformation in the lower crust and is not related to flat-slab subduction.

  3. Age and depositional setting of the type Lospe Formation (Lower Miocene), Santa Maria basin, central California

    SciTech Connect

    Stanley, R.G. ); Johnson, S.Y.; Obradovich, J.D.; Tuttle, M.L. ); Thornton, M.L.C.; Vork, D.R.; Filewicz, M.V. ); Mason, M.A. ); Swisher, C.C. III )

    1990-05-01

    The Lospe Formation is an 800-m-thick sequence of sedimentary and minor volcanic rocks at the base of the petroliferous Neogene Santa Maria basin of central California. In its type area in the Casmalia Hills, the Lospe rests unconformably on Jurassic ophiolite, is conformably overlain by the lower Miocene (Sauceian and Relizian) Point Sal Formation, and is of earliest Miocene (Saucesian) age on the basis of palynomorphs, benthic foraminifers, and radiometric dating of tuffs. Alluvial fan and fan-delta facies at the base of the Lospe are as much as 200 m thick and consist mainly of conglomerate and sandstone derived from nearby fault-bounded uplifts of Mesozoic rocks. These coarse sediments grade upward into a sequence of interbedded turbidite sandstone and mudstone that accumulated in a lake or restricted coastal embayment. Lenses of tuff as much as 20 m thick occur sporadically throughout this sequence and contain blocks of Jurassic ophiolite up to 50 m long and 20 m across. The uppermost 30 m of the Lospe consist of storm-deposited sandstone and mudstone containing shallow marine microfossils. That these shelf deposits are abruptly overlain by black shale of the Point Sal Formation indicates rapid deepening to oxygen-poor bathyal environments. Overall, the Lospe Formation is a fining-upward sequence that records active faulting, volcanism, and a change from nonmarine to marine depositional environments during the initial formation of the Neogene Santa Maria basin. This history is consistent with several competing tectonic models that variously explain the origin of the basin as the result of regional rifting or local rotation of small crustal blocks.

  4. Simulations of Precipitation Variability over the Upper Rio Grande Basin

    SciTech Connect

    Costigan, Keeley R.; Bossert, James E.; Langley, David L.

    1997-12-31

    In this research, we study Albuquerque`s water and how it may be affected by changes in the regional climate, as manifested by variations in Rio Grande water levels. To do this, we rely on the use of coupled atmospheric, runoff, and ground water models. Preliminary work on the project has focused on uncoupled simulations of the aquifer beneath Albuquerque and winter precipitation simulations of the upper Rio Grande Basin. The latter is discussed in this paper.

  5. Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

    SciTech Connect

    Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby

    2006-05-26

    The principal research effort for Phase 1 (Concept Development) of the project has been data compilation; determination of the tectonic, depositional, burial, and thermal maturation histories of the North Louisiana Salt Basin; basin modeling (geohistory, thermal maturation, hydrocarbon expulsion); petroleum system identification; comparative basin evaluation; and resource assessment. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, and regional cross sections have been prepared. Structure, isopach and formation lithology maps have been constructed, and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and burial history, thermal maturation history, and hydrocarbon expulsion profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs include Upper Jurassic and Cretaceous fluvial-deltaic sandstone facies; shoreline, marine bar and shallow shelf sandstone facies; and carbonate shoal, shelf and reef facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary. Hydrocarbon

  6. 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

  7. Statistical downscaling of temperature using three techniques in the Tons River basin in Central India

    NASA Astrophysics Data System (ADS)

    Duhan, Darshana; Pandey, Ashish

    2015-08-01

    In this study, downscaling models were developed for the projections of monthly maximum and minimum air temperature for three stations, namely, Allahabad, Satna, and Rewa in Tons River basin, which is a sub-basin of the Ganges River in Central India. The three downscaling techniques, namely, multiple linear regression (MLR), artificial neural network (ANN), and least square support vector machine (LS-SVM), were used for the development of models, and best identified model was used for simulations of future predictand (temperature) using third-generation Canadian Coupled Global Climate Model (CGCM3) simulation of A2 emission scenario for the period 2001-2100. The performance of the models was evaluated based on four statistical performance indicators. To reduce the bias in monthly projected temperature series, bias correction technique was employed. The results show that all the models are able to simulate temperature; however, LS-SVM models perform slightly better than ANN and MLR. The best identified LS-SVM models are then employed to project future temperature. The results of future projections show the increasing trends in maximum and minimum temperature for A2 scenario. Further, it is observed that minimum temperature will increase at greater rate than maximum temperature.

  8. Trend analysis of selected water-quality constituents in the Verde River Basin, central Arizona

    SciTech Connect

    Baldys, S. )

    1990-01-01

    Temporal trends of eight water quality constituents at six data collection sites in the Verde River basin in central Arizona were investigated using seasonal Kendall tau and ordinary least-squares regression methods of analysis. The constituents are dissolved solids, dissolved sulfate, dissolved arsenic, total phosphorus, pH, total nitrite plus nitrate-nitrogen, dissolved iron, and fecal coliform bacteria. Increasing trends with time in dissolved-solids concentrations of 7 to 8 mg/L/yr at Verde River near Camp Verde were found at significant level. An increasing trend in dissolved-sulfate concentrations of 3.59 mg/L/yr was also found at Verde River near Camp Verde, although at nonsignificant levels. Statistically significant decreasing trends with time in dissolved-solids and dissolved-sulfate concentrations were found at Verde River above Horseshoe Reservoir, which is downstream from Verde River near Camp Verde. Observed trends in the other constituents do not indicate the emergence of water quality problems in the Verde River basin. Analysis of the eight water quality constituents generally indicate nonvarying concentration levels after adjustment for seasonality and streamflow were made.

  9. Chemostratigraphy of Upper Cretaceous chalk sequences in Norwegian-Danish basin and North Sea Central Trough

    SciTech Connect

    Joergensen, N.O.

    1987-05-01

    Geochemical studies of subsurface sections and outcrops in the Upper Cretaceous chalk sequences from the Norwegian-Danish basin and the North Sea Central Trough have resulted in a detailed chemostratigraphy for these strata. The most applicable chemostratigraphic markers are based on the distribution of strontium, magnesium, manganese, the /sup 13/C//sup 12/C ratio, and the variations in the carbonate contents. It is demonstrated that the chemostratigraphic approach is valid at two levels: (1) a superior chemostratigraphy in which deep-sea cores from the Atlantic Ocean and sections from western Europe are correlated on the basis of significant geochemical anomalies and long-term variations most likely induced by oceanic geochemical cycles and sea level fluctuations; (2) a subordinate but detailed intrabasinal chemostratigraphic correlation which primarily reflects the physicochemical conditions in the depositional environment. The Upper Cretaceous chemostratigraphy established in the Danish area allows a detailed correlation between relatively continuous chalk sequences in the Norwegian-Danish basin and the rather condensed and hiati-influenced sections in the oil fields of the North Sea. The results emphasize the applicability of chemostratigraphy in the subsurface exploration for hydrocarbon reservoirs in chalk.

  10. Radiocarbon age distribution of groundwater in the Konya Closed Basin, central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Bayari, C. Serdar; Ozyurt, N. Nur; Kilani, Susan

    2009-03-01

    Annual abstraction of 2.6 × 109 m3 of groundwater in the 53,000 km2 Konya Closed Basin of central Turkey has caused a head decline of 1 m/year over the last few decades. Therefore, understanding the hydrogeology of this large endorheic basin, in a semi-arid climate, is important to sustainable resource management. For this purpose, the groundwater’s radiocarbon age distribution has been investigated along a 150-km transect parallel to regional flow. Results show that the groundwater ranges in age from Recent at the main recharge area of the Taurus Mountains in the south, to about 40,000 years around the terminal Salt Lake located in the north. In this predominantly confined flow system, radiocarbon ages increase linearly by distance from the main recharge area and are in agreement with the hydraulic ages. The mean velocity of regional groundwater flow (3 m/year) is determined by the rate of regional groundwater discharge into the Salt Lake. Calcite dissolution, dedolomitization and geogenic carbon dioxide influx appear to be the dominant geochemical processes that determine the carbon isotope composition along the regional flow path. The groundwater’s oxygen-18 content indicates more humid and cooler paleorecharge. A maximum drop of 5°C is inferred for the past recharge temperature.

  11. Burial diagenesis of upper Mississippian Greenbrier limestone in central Appalachian basin

    SciTech Connect

    Carney, C.

    1987-09-01

    As carbonate sediments undergo progressive burial under conditions of increasing temperature and pressure, they go through a variety of changes. Burial diagenesis includes processes such as mechanical and chemical compaction, mineralogic change, cementation, dolomitization, and various types of neomorphic fabric change. Identifying the products of burial diagenesis may be useful in predicting porosity and reservoir quality in the subsurface. The Upper Mississippian Greenbrier Limestone and equivalents are exposed throughout the central Appalachians. Important textural and mineralogical changes have been recognized in these shallow shelf limestones, which indicate burial to different depths. Variations in trace- and minor-element concentrations occur with increasing diagenesis. Textural alterations include increased matrix (micrite) crystal size and increased twinning of echinoderm fragments. The Greenbrier Limestone can be divided into three diagenetic provinces. Zone 1, located on the extreme western side of the basin, is characterized by little evidence of compaction, mineralogic variation, or textural change. In this area, the limestones were never buried to any great depth. Zone 3, on the eastern side of the basin, is characterized by significant mechanical and chemical compaction, and mineralogic and textural change. Limestones of this diagenetic province have been subjected to relatively high paleotemperatures during deep burial. Zone 2 is of intermediate burial depth and diagenesis and is present between zones 1 and 3.

  12. Ground-water availability in the central part of Lake Ontario basin, New York

    USGS Publications Warehouse

    Miller, Todd S.; Krebs, Martha M.

    1988-01-01

    A set of three maps showing surficial geology, distribution of glacial aquifers, and potential well yield in the 708 sq mi central part of the Lake Ontario basin are presented at a scale of 1:125,000. The basin is parallel to Lake Ontario and extends from Rochester in the west to Oswego in the east. Aquifers consisting primarily of sand and gravel formed where meltwaters from glaciers deposited kame and outwash sand and gravel and where wave action along shores of glacial lakes eroded, reworked , and deposited beaches. Thick deposits of well-sorted sand and gravel yield relatively large quantities of water - typically more than 100 gal/min. Aquifers consisting of thin beds of sand and (or) gravel or thick gravel that contain a large proportion of silt and fine sand yield moderate amounts of water, 10 to 100 gal/min. Dug and driven wells that tap fine to medium sand deposits typically yield 1 to 10 gal/min. (USGS)

  13. Physical characteristics of stream subbasins in the Chippewa River basin, west-central Minnesota

    USGS Publications Warehouse

    Sanocki, C.A.; Krumrie, J.R.

    1994-01-01

    Data that describe the physical characteristics of stream subbasins upstream from selected points on streams in the Chippewa River Basin, located in west-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. The points on the stream 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.

  14. Coal quality controls of the Danville coal in Indiana (Illinois Basin, Central USA)

    USGS Publications Warehouse

    Mastalerz, Maria; Padgett, P.L.

    2002-01-01

    The Danville Coal Member (Dugger Formation, upper Desmoinesian, Pennsylvanian) is a significant economic coal resource in the Illinois Basin, central USA. Deposition of the Danville Coal (peat) was in coastal environments, varying distances from the coastline and, in turn, variable influences from saline waters. The purpose of this study is to examine the coal quality and petrography of the Danville Coal; and to discuss their relationship with depositional environment as it relates to the final coal product. A medium sulfur (1.0-1.5 wt.%) Danville Coal reserve area (northern Indiana coalfield) was compared to a low sulfur (3 m) of finer-grained clastic sediments atop the Danville, the sulfur and trace elements contents are significantly lower. ?? 2002 Elsevier Science B.V. All rights reserved.

  15. Paleoclimatic inferences from an isotopic investigation of groundwater in the central San Juan Basin, New Mexico

    NASA Astrophysics Data System (ADS)

    Phillips, Fred M.; Peeters, Leslie A.; Tansey, Michael K.; Davis, Stanley N.

    1986-09-01

    Groundwater from the Ojo Alamo and Nacimiento aquifers in the central San Juan Basin. New Mexico, has yielded 14C ages ranging from modern to 35,000 yr B.P. The Pleistocene-age samples are characterized by a stable isotope content about 25‰ lighter in D and 3‰ lighter in 18O than modern precipitation and groundwater. We attribute this difference to a colder mean annual temperature and perhaps increased winter precipitation. Consideration of various factors controlling the stable isotope composition of the groundwater allows estimation of a 5° to 7°C temperature decrease during the late Wisconsin, accompanied by increased effective precipitation. A similar estimate of the temperature change is obtained from noble-gas paleothermometry. These data support a model of moderately cooler late Pleistocene climate in the American Southwest characterized by summers with less precipitation than today, but wetter winters.

  16. A relation among geology, tectonics, and velocity structure, western to central Nevada Basin and Range

    USGS Publications Warehouse

    Catchings, R.D.

    1992-01-01

    In the northwestern to central Nevada Basin and Range, there are correlations between velocity and specific geologic structures of the crust. Mapped range-bounding faults at the surface can be traced to appreciable (10km) depths based on velocity variations and are consistent with subsurface projections of the faults based on seismic reflection images. Correlations between velocity and the surface geology show that in the upper crust the pre-Cenozoic rocks are underlain by high-velocity rocks, whereas the Tertiary ranges are underlain by lower-velocity rocks to depths as great as 10 km. The regional seismicity pattern is consistent with this interpretation, as earthquakes are largely confined within or near the base of the low-velocity rocks. These low-velocity, highly fractured rocks are laterally distributed in discrete zones, suggesting that extension is not uniformly distributed but occurs in discrete, highly extended zones. -from Author

  17. Late Cenozoic crustal deformation of the north-central Basin and Range

    SciTech Connect

    Eyal, Y. . Dept. of Geology); Ron, H. )

    1993-04-01

    Late Cenozoic deformation of Basin and Range in north-central Nevada is examined by small fault analysis. Consistency between fault types, fault trends and sense of displacement was found for this area in which normal faults strike N-S, and right-lateral and left-lateral faults strike NNW and NNE respectively. The existence of strike-slip faulting, mainly right-lateral, is consistent with horizontal counter clockwise rotation suggested by paleomagnetic declination data. The results of this analysis indicate that crustal deformation of this area did not occur by only simple E-W uniaxial extension but also by N-S compression and shortening, and that the contribution of strike slip faulting to the extension of this area is substantial almost similar to that of normal faulting.

  18. Ground water for irrigation in the Viking Basin, west-central Minnesota

    USGS Publications Warehouse

    McBride, M.S.

    1975-01-01

    The Viking Basin consists of six glacial outwash areas in Douglas, Ottertail, and Todd Counties, west-central Minnesota. Total area is 340 square miles (880 square kilometres). Soils are sandy and excessively well-drained. Crops grown on the outwash would benefit from supplemental irrigation. Irrigation supplies can be obtained from wells in the surface outwash aquifer in significant parts of the large outwash areas near Carlos and Parkers Prairie and the small outwash area near Clotho. Irrigation supplies are unlikely in the outwash areas near Alexandria, Urbank, and Rose City. Major use of ground water for irrigation may lower ground-water levels sufficiently to affect lake and marsh levels and streamflow out of the irrigation areas. Water from the outwash is of excellent chemical quality for irrigation.

  19. The organic geochemistry of the Eocene-Oligocene black shales from the Lunpola Basin, central Tibet

    NASA Astrophysics Data System (ADS)

    Sun, Tao; Wang, Chengshan; Duan, Yi; Li, Yalin; Hu, Bin

    2014-01-01

    This paper reports on the depositional paleoenvironment and the potential hydrocarbons of the Eocene-Oligocene black shales from the Dingqinghu and Niubao Formations in the Lunpola Basin, central Tibet. Nineteen samples from two outcrop profiles were analysed. The contents of the total organic carbon (TOC) and sulphur were measured; other analyses included Rock-Eval pyrolysis, solvent extraction and gas chromatography-mass spectrometer (GC-MS). The results indicated that the shales from the Dingqinghu and Niubao Formations are thermally immature. The pyrolysis data show that the shales contain Type I organic matter and that lacustrine algal are the main organic matter sources. The low pristane to phytane ratios and the high gammacerane indices indicate that the shales were deposited in a reducing, stratified, and hypersaline palaeo-lake, which is consistent with the climate information provided by the development history of palaeo-lakes from the Eocene to the Oligocene epochs.

  20. 1989 Environmental monitoring report, Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Hwang, S.; Chavez, G.; Phelan, J.; Parsons, A.; Yeager, G.; Dionne, D.; Schwartz, B.; Wolff, T.; Fish, J.; Gray, C.; Thompson, D.

    1990-05-01

    This 1989 report contains monitoring data from routine radiological and nonradiological environmental surveillance activities. Summaries of significant environmental compliance programs in progress such as National Environmental Policy Act documentation, environmental permits, environmental restoration, and various waste management programs for Sandia National Laboratories in Albuquerque (SNL, Albuquerque) are included. The maximum offsite dose impact was calculated to be 8.8 {times} 10{sup {minus}4} mrem. The total Albuquerque population received a collective dose of 0.097 person-rem during 1989 from SNL, Albuquerque, operations. As in the previous year, SNL, Albuquerque, operations in 1989 had no adverse impact on the general public or on the environment. 46 refs., 20 figs., 31 tabs.

  1. 1991 Environmental monitoring report Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Culp, T.; Cox, W.; Hwang, S.; Jones, A.; Longley, S.; Parsons, A.; Wolff, T.; Fish, J.; Ward, S.

    1992-11-01

    This 1991 report contains monitoring data from routine radiological and nonradiological environmental surveillance activities. Summaries of significant environmental compliance programs in progress such as National Environmental Policy Act (NEPA) documentation, environmental permits, environmental restoration (ER), and various waste management programs for Sandia National Laboratories in Albuquerque (SNL, Albuquerque) are included. The maximum offsite dose impact was calculated to be 1.3 {times} 10{sup {minus}3} mrem. The total population within a 50-mile radius of SNL, Albuquerque, received a collective dose of 0.53 person-rem during 1991 from SNL, Albuquerque, operations. As in the previous year, the 1991 operations at SNL, Albuquerque, had no discernible impact on the general public or on the environment.

  2. MIS5 hydrological variability from continental carbonates from the Sulmona Basin (central Italy)

    NASA Astrophysics Data System (ADS)

    Regattieri, Eleonora; Giaccio, Biagio; Zanchetta, Giovanni; Drysdale, Russell; Galli, Paolo; Nomade, Sebastien; Peronace, Edoardo; Wulf, Sabine

    2015-04-01

    There are few highly resolved, chronologically well-anchored continental records documenting the MIS5 climatic instability over Mediterranean area, particularly for montane sites. Understanding rapid climate changes in high-altitude areas is of particular relevance because water availability in the Mediterranean basin is generally scarce and unevenly distributed, and mostly dependent on runoff from mountain areas. Here we present a multiproxy record (δ18O, δ13C and CaCO3 content) from a lacustrine succession in the Sulmona basin (Abruzzo, central Italy) which spans the period ca. 90 to 120 ka. The succession is chronologically anchored by means on tephrochronology (40Ar/39Ar dating) and tephras correlations. The observed millennial variability is interpreted in terms of hydrological changes (i.e. amount and seasonality of the precipitation) and it is consistent with coeval well dated speleothem isotope record from central Italy, testifying the regional significance of δ18O variations and the accuracy of the proposed age model. The observed features correlate well also with Greenland stadials/interstadials from GI25 to GI22 and with North Atlantic cold events from C25 to C22, which are expressed as period of reduced precipitation. The correlations with high latitudes records indicate a strong Mediterranean-North Atlantic climate teleconnection during this period. The record also show different amplitude and expression of the wetter period interspersed among the Greenland stadials/North Atlantic C events. Correlations with pollen records allow to disentangle the seasonality pattern of the precipitation and potentially to unravel the modulation of the hydrological signal exerted by low-latitudes teleconnections on Mediterranean climate, especially during periods of enhanced monsoon activity.

  3. Orbital chronology of the Pliensbachian - Toarcian transition from the Central High Atlas Basin (Morocco)

    NASA Astrophysics Data System (ADS)

    Martinez, Mathieu; Krencker, François-Nicolas; Mattioli, Emanuela; Bodin, Stéphane

    2016-04-01

    The Pliensbachian - Toarcian transition is a period of dramatic changes in climate, sea level and paleobiodiversity. These changes cause important fluctuations in sedimentary patterns, including facies and sedimentation rates, so that a series of condensation and hiatal surfaces affects the sedimentary series of the Northern Tethyan margin. The recurrence of condensation in the studied sections makes uncertain the previous orbital calibration at the Pliensbachian - Toarcian transition. The Central High Atlas Basin experienced in the early Jurassic high subsidence and sedimentation rates. δ13C and CaCO3 have been measured at a high resolution and spectral analyses were performed using the multi-taper method and the evolutive fast Fourier transform. Significant cycles are observed at 16 m, 1.7 m and 0.9 m, and are respectively related to the 405-kyr eccentricity, the main obliquity and the precession cycles. The orbital calibration of the Foum Tillicht section, correlable to the orbital calibration of the Peniche section shows that the Tenuicostatum/Polymorphum Zone has a duration of 0.9 - 1.0 myr. The FO of C. superbus in the Tethyan occurs ~0.55 myr above the base of the Tenuicostatum/Polymorphum Zone. Finally, the duration of the P-To event, a carbon-isotope excursion, has a duration ranging from 0.18 to 0.27 myr. Correlations of the astrochronological frameworks between the Foum Tillicht and the Peniche sections shows that the Peniche is condensed at the P-To event, while the Foum Tillicht section is affected by a 0.2-0-3-myr-long hiatus at the Polymorphum - Levisoni transition. These condensed and hiatal intervals are correlated to the main condensation phases observed in the Tethyan realm at the Pliensbachian - Toarcian transition. We finally explore the potential of the Central High Atlas basin to provide a refined time scale for the upper Pliensbachian.

  4. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2004-02-05

    The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule. The principal objectives of the project are to develop through basin analysis and modeling the concept that petroleum systems acting in a basin can be identified through basin modeling and to demonstrate that the information and analysis resulting from characterizing and modeling of these petroleum systems in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin can be used in providing a more reliable and advanced approach for targeting stratigraphic traps and specific reservoir facies within a geologic system and in providing a refined assessment of undiscovered and underdeveloped reservoirs and associated oil and gas resources.

  5. Permian and Triassic microfloral assemblages from the Blue Nile Basin, central Ethiopia

    NASA Astrophysics Data System (ADS)

    Dawit, Enkurie L.

    2014-11-01

    Palynological investigation was carried out on surface samples from up to 400 m thick continental siliciclastic sediments, here referred to as “Fincha Sandstone”, in the Blue Nile Basin, central Ethiopia. One hundred sixty species were identified from 15 productive samples collected along a continuous road-cut exposure. Six informal palynological assemblage zones have been identified. These assemblage zones, in ascending order, are: “Central Ethiopian Permian Assemblage Zone - CEPAZ I”, earliest Permian (Asselian-Sakmarian); “CEPAZ II”, late Early Permian (Artinskian-Kungurian); CEPAZ III - Late Permian (Kazanian-Tatarian); “CETAZ IV”, Lower Triassic (Olenekian Induan); “CETAZ V”, Middle Triassic (Anisian Ladinian); “CETAZ VI”, Late Triassic (Carnian Norian). Tentative age ranges proposed herein are compared with faunally calibrated palynological zones in Gondwana. The overall composition and vertical distribution of miospores throughout the studied section reveals a wide variation both qualitatively and quantitatively. The high frequency of monosaccate pollen in CEPAZ I may reflect a Glossopterid-dominated upland flora in the earliest Permian. The succeeding zone is dominated by straite/taeniate disaccate pollen and polyplicates, suggesting a notable increase in diversity of glossopterids. The decline in the diversity of taeniate disaccate pollen and the concomitant rise in abundance of non-taeniate disaccates in CEPAZ III may suggest the decline in Glossopteris diversity, though no additional evidence is available to equate this change with End-Permian extinction. More diverse and dominant non-taeniate, disaccate, seed fern pollen assignable to FalcisporitesAlisporites in CETAZ IV may represent an earliest Triassic recovery flora. The introduction of new disaccate forms with thick, rigid sacci, such as Staurosaccites and Cuneatisporites, in CETAZ V and VI may indicate the emergence of new gymnospermous plants that might have favourably

  6. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini; Donald A. Goddard; Ronald K. Zimmerman

    2005-05-10

    The principal research effort for Year 2 of the project has been data compilation and the determination of the burial and thermal maturation histories of the North Louisiana Salt Basin and basin modeling and petroleum system identification. In the first nine (9) months of Year 2, the research focus was on the determination of the burial and thermal maturation histories, and during the remainder of the year the emphasis has basin modeling and petroleum system identification. Existing information on the North Louisiana Salt Basin has been evaluated, an electronic database has been developed, regional cross sections have been prepared, structure and isopach maps have been constructed, and burial history, thermal maturation history and hydrocarbon expulsion profiles have been prepared. Seismic data, cross sections, subsurface maps and related profiles have been used in evaluating the tectonic, depositional, burial and thermal maturation histories of the basin. Oil and gas reservoirs have been found to be associated with salt-supported anticlinal and domal features (salt pillows, turtle structures and piercement domes); with normal faulting associated with the northern basin margin and listric down-to-the-basin faults (state-line fault complex) and faulted salt features; and with combination structural and stratigraphic features (Sabine and Monroe Uplifts) and monoclinal features with lithologic variations. Petroleum reservoirs are mainly Upper Jurassic and Lower Cretaceous fluvial-deltaic sandstone facies and Lower Cretaceous and Upper Cretaceous shoreline, marine bar and shallow shelf sandstone facies. Cretaceous unconformities significantly contribute to the hydrocarbon trapping mechanism capacity in the North Louisiana Salt Basin. The chief petroleum source rock in this basin is Upper Jurassic Smackover lime mudstone beds. The generation of hydrocarbons from Smackover lime mudstone was initiated during the Early Cretaceous and continued into the Tertiary

  7. Description of piezometers installed in the Duranes well field area, Albuquerque, New Mexico

    USGS Publications Warehouse

    Thorn, C.R.

    1998-01-01

    Since 1993, the aquifer system in the Middle Rio Grande Basin, and particularly in the Albuquerque area, has been the focus of studies to further define the extent of the most productive parts of the aquifer and to gain a better understanding of ground-water/surface-water interactions. Twenty-one piezometers were installed during January and February 1997 at five sites in the Duranes well field area in Albuquerque, New Mexico, to allow for concentrated collection of hydraulic-head data. This concentrated collection of shallow hydraulic-head data may lead to a better understanding of the effects of ground-water production on the Rio Grande near a City of Albuquerque well field. Each piezometer was installed in a hole augered by a rig using hollow-stem auger flights. All piezometers are constructed of flush-joint polyvinyl chloride casing with 5-foot polyvinyl chloride screens. The uppermost 2 feet of the piezometer casing is covered by a steel casing with a locking lid. Driller's logs and geophysical logs were collected from the deepest hole and piezometer, respectively, at each site. This report describes the piezometers installed and presents initial water- level data for all piezometers.

  8. Basin Analysis and Petroleum System Characterization and Modeling, Interior Salt Basins, Central and Eastern Gulf of Mexico

    SciTech Connect

    Ernest A. Mancini

    2005-03-31

    The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.

  9. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2004-11-05

    The principal research effort for Year 2 of the project is the determination of the burial and thermal maturation histories and basin modeling and petroleum system identification of the North Louisiana Salt Basin. In the first six (6) to nine (9) months of Year 2, the research focus is on the determination of the burial and thermal maturation histories and the remainder of the year the emphasis is on basin modeling and petroleum system identification. No major problems have been encountered to date, and the project is on schedule.

  10. Extensional Basins in a Convergent Margin: Oligocene-Early Miocene Salar de Atacama and Calama basins, Central Andes

    NASA Astrophysics Data System (ADS)

    Jordan, T. E.; Mpodozis, C.; Blanco, N.; Pananont, P.; Dávila, F.

    2004-12-01

    The Salar de Atacama Basin (SdAB) is the largest and most persistent sedimentary basin of northern Chile, accumulating nonmarine sediment from Cretaceous to modern times. Its northwestern neighbor, the Calama, was a Cenozoic basin. Although SdAB was in the backarc zone early in the Andean orogeny, both are now forearc basins. Others demonstrated that the basins overlie anomalously cold, strong, and dense crust and lithosphere. We focus on an extensional Oligocene basin stage. Interpretation of the basin-controlling faults is based on seismic reflection studies supported by field relations. The SdAB is limited to the west by the NNE-trending, steeply east-dipping, Paciencia Fault (PF). The PF experienced 5-7 km of down-to-the-east offset during the Oligocene-early Miocene. Syntectonic strata, an arid succession of siliciclastics and evaporites, are asymmetric, with thicknesses of 5000 m and abundant halite adjacent to the PF, and of 1000 m with fine detrital clastic strata 25 km farther east. Relations in conglomeratic growth strata that overlap the PF also demonstrate normal displacement during sediment accumulation. Seismic data reveal that a buried normal fault with 1-1.5 km down-to-the-east displacement limits the western margin of the Oligocene-Miocene Calama siliciclastic basin fill. Regionally, Oligocene-early Miocene margin-parallel strike-slip deformation dominated northwest of the basins, contributing sinistral offset (West Fissure Fault) to the northern segment of the long-lived Domeyko Fault System. The new SdAB and Calama data reveal that a 20,000 km2 domain of extensional basins existed within the dominantly strike-slip region. Even if PF and the fault in the Calama Basin were transtensional, the proportion of extension to strike-slip displacement is much greater in these basins than elsewhere in northern Chile. Further study is required to understand what combination of factors caused this kinematic distinction as well as delayed the onset of CVZ

  11. Neogene transpressional foreland basin development on the north side of the central alaska range, usibelli group and nenana gravel, tanana basin

    USGS Publications Warehouse

    Ridgway, K.D.; Thoms, E.E.; Layer, P.W.; Lesh, M.E.; White, J.M.; Smith, S.V.

    2007-01-01

    Neogene strata of the Tanana basin provide a long-term record of a northwardpropagating, transpressional foreland-basin system related to regional shortening of the central Alaska Range and strike-slip displacement on the Denali fault system. These strata are ???2 km thick and have been deformed and exhumed in thrust faults that form the foothills on the north side of the Alaska Range. The lower part of the sedimentary package, the Usibelli Group, consists of 800 m of mainly Miocene strata that were deposited in fluvial, lacustrine, and peat bog environments of the foredeep depozone of the foreland-basin system. Compositional data from conglomerate and sandstone, as well as recycled Upper Cretaceous palynomorphs, indicate that the Miocene foreland-basin system was supplied increasing amounts of sediment from lithologies currently exposed in thrust sheets located south of the basin. The upper part of the sedimentary package, the Nenana Gravel, consists of 1200 m of mainly Pliocene strata that were deposited in alluvial-fan and braidplain environments in the wedge-top depozone of the foreland-basin system. Compositional data from conglomerate and sandstone, as well as 40Ar/39Ar dating of detrital feldspars in sandstone and from granitic clasts in conglomerate, indicate that lithologies exposed in the central Alaska Range provided most of the detritus to the Pliocene foreland-basin system. 40Ar/39Ar dates from detrital feldspar grains also show that two main suites of plutons contributed sediment to the Nenana Gravel. Detrital feldspars with an average age of 56 Ma are interpreted to have been derived from the McKinley sequence of plutons located south of the Denali fault. Detrital feldspars with an average age of 34 Ma are interpreted to have been derived from plutons located north of the Denali fault. Plutons located south of the Denali fault provided detritus for the lower part of the Nenana Gravel, whereas plutons located north of the Denali fault began to

  12. Nitrous acid in Albuquerque, New Mexico, homes

    SciTech Connect

    Spengler, J.D.; Brauer, M. ); Samet, J.M.; Lambert, W.E. )

    1993-05-01

    Experimental studies have shown that nitrogen acid species, particularly nitrous acid, are formed indoors during unvented combustion and by heterogeneous reactions of nitrogen dioxide. Limited measurements support the occurrence of nitrous acid production in occupied homes. The authors report additional measurements of HONO and NO[sub 2] in homes located in Albuquerque, NM, and assess the relationship with housing variables. Indoor HONO concentrations were found to be well correlated with indoor NO[sub 2] levels; HONO concentrations ranged from 5% to 15% of the measured NO[sub 2] concentrations. Given the correlation between HONO and NO[sub 2] in indoor environments, and the plausibility of HONO respiratory toxicity, investigations of respiratory health effects of unvented combustion should consider HONO, in addition to NO[sub 2], as a potentially hazardous indoor pollutant. 38 refs., 2 figs., 2 tabs.

  13. Implementation of MAR within the Rio Grande Basin of Central New Mexico, USA

    NASA Astrophysics Data System (ADS)

    Marley, Robert; Blandford, T. Neil; Ewing, Amy; Webb, Larry; Yuhas, Katherine

    2014-05-01

    The U.S. Bureau of Reclamation has identified the Rio Grande basin within Central New Mexico as one of several regions where water supplies are over-allocated and future conflicts over the inadequate resource are highly likely. Local water providers have consistently identified managed aquifer recharge (MAR) as an important tool to provide conjunctive management of surface-water, groundwater, and reclaimed water sources in order to extend the useful life of existing water sources. However, MAR projects have been slow to take root partly due to rigorous demonstration requirements, groundwater quality protection concerns, and ongoing water right uncertainties. At first glance the several thousand meters of unconsolidated basin-fill sediments hosting the regional aquifer appear to provide an ideal environment for the subsurface storage of surplus water. However, the basin has a complex structural and depositional history that impacts the siting and overall effectiveness of MAR systems. Several recharge projects are now in various stages of implementation and are overcoming site specific challenges including source water and ambient groundwater compatibility, low-permeability sediments and compartmentalization of the aquifer by extensive faulting, well clogging, and overall water quality management. This presentation will highlight ongoing efforts of these water providers to develop full-scale recharge facilities. The performance of natural in-channel infiltration, engineered infiltration galleries, and direct injection systems designed to introduce from 500 to 5,000 mega-liters per annum to target intervals present from 150 to 600 meters below ground surface will be described. Source waters for recharge operations include inter-basin transferred surface water and highly treated reclaimed water sources requiring from minor to extensive treatment pre-recharge and post-recovery. Operational complexities have raised concerns related to long-term operation and maintenance

  14. Molluscan fauna from core 25B, Whipray Basin, central Florida Bay, Everglades National Park

    USGS Publications Warehouse

    Trappe, Carleigh A.; Brewster-Wingard, G. Lynn

    2001-01-01

    Molluscan assemblages preserved in an 80-cm core from Whipray Basin in central Florida Bay, Everglades National Park, illustrate changes in the environmental conditions within the basin over the last two centuries. Salinity remained polyhaline to euhaline throughout the time of deposition (1800-1997), with alternating periods of stability and increased fluctuations. Since 1800, a Brachidontes assemblage has characterized Whipray Basin and the dominant faunal components have remained the same in terms of presence and absence of species. However, patterns of dominance and diversity within the Brachidontes assemblage have changed and these changes indicate fluctuations in the environment. The period from 1815 to 1857 was distinguished by an abundance of molluscs dwelling on seagrass and sub-aquatic vegetation. Faunal richness and abundance were high and stable, and epiphytic molluscs flourished. Polyhaline conditions existed, although periods of slightly lower salinities occurred. The period from 1862 to 1894 appears unstable based on fluctuations in molluscan faunal richness, abundance, and dominant species. The epiphytic molluscs experienced significant shifts (? >30%) associated with changes in sub-aquatic vegetation. The changes in epiphytic molluscs from 1871 to 1913 may be indicative of a seagrass die-off. The period from 1899 to 1950 was the most stable section of the core in terms of changes in the molluscan fauna. Faunal richness and abundance reached highs of 31 groups and 726 individuals per sample during this period and epiphytic molluscs were prevalent. Beginning in 1955, faunal groups experienced high amplitude fluctuations in abundance; this pattern continued through the second half of the 20th century. Fluctuating salinity, changes in vegetation, and reduced water quality (low O2, increased nutrients and/or reduced clarity) oxygen supply) have characterized the past 50 years. These changes preceded a seagrass die-off in 1987-88 and may be related to

  15. Cenozoic sedimentary dynamics of the Ouarzazate foreland basin (Central High Atlas Mountains, Morocco)

    NASA Astrophysics Data System (ADS)

    El Harfi, A.; Lang, J.; Salomon, J.; Chellai, E. H.

    2001-06-01

    Cenozoic continental sedimentary deposits of the Southern Atlas named "Imerhane Group" crop out (a) in the Ouarzazate foreland basin between the Precambrian basement of the Anti Atlas and the uplifted limestone dominated High Atlas, and (b) in the Aït Kandoula and Aït Seddrat nappes where Jurassic strata detached from the basement have been thrust southwards over the Ouarzazate Basin. New biostratigraphic and geochronological data constraining the final Eocene marine regression, the characterization of the new "Aït Ouglif Detrital Formation" presumed to be of Oligocene age, and the new stratigraphic division proposed for the Continental Imerhane Group clarify the major tectonogenetic alpidic movements of the Central High Atlas Range. Four continental formations are identified at regional scale. Their emplacement was governed principally by tectonic but also by eustatic controls. The Hadida and Aït Arbi formations (Upper Eocene) record the major Paleogene regression. They are composed of margino-littoral facies (coastal sabkhas and fluviatile systems) and reflect incipient erosion of the underlying strata and renewed fluvial drainage. The Aït Ouglif Formation (presumed Oligocene) had not been characterized before. It frequently overlies all earlier formations with an angular unconformity. It includes siliciclastic alluvial deposits and is composed predominantly of numerous thin fining-upward cycles. The Aït Kandoula Formation (Miocene-Pliocene) is discordant, extensive, and represents a thick coarsening-upward megasequence. It is composed of palustro-lacustrine deposits in a context of alluvial plain with localized sabkhas, giving way to alluvial fans and fluviatile environments. The Upper Conglomeratic Formation (Quaternary) is the trace of a vast conglomeratic pediment, forming an alluvial plain and terraces. The second and third formations correspond to two megasequences engendered by the uplift of the Central High Atlas in two major compressive phases

  16. Morphology and evolution of salt/mini-basin systems: Lower shelf and upper slope, central offshore Louisiana

    SciTech Connect

    Sumner, H.S.; Robinson, B.A.; Dirks, W.K.; Holliday, J.C. )

    1991-03-01

    A complex array of deformed salt bodies and localized salt withdrawal depocenters termed 'mini-basins' dominate the subsurface geology of the central Louisiana lower shelf and upper slope. Individual salt bodies climb basinward as horizontal sills supplied by vertical to inclined 'feeders.' Each level of salt remobilization and emplacement is overlain by an association of structural features that occurs repetitively in space and time owing to sediment loading caused by progradation of Miocene to Recent shelf margins. Mini-basins are generally circular to elliptical (in map view) and contain thick sequences of sediment ponded by salt withdrawal. Mini-basins on the slope typically have a simple symmetric to asymmetric internal structure and are often almost entirely bounded by large, bathymetrically high salt bodies. Salt displaced out of slope mini-basins is loaded by the advancing shelf margin, initiating formation of shelf mini-basins. Shelf mini-basins generally have well-defined fault/piercement salt boundaries and a strongly asymmetric to the south internal structure. Salt displaced downdip by shelf mini-basin loading forms major shallow-seated sill-like bodies that intrude upper slope strata. Subsequent reactivation of these allochthonous salt sills often results in a secondary level of structural features that detach on a salt withdrawal surface ('Roho'). Salt/mini-basin systems exert a profound influence on hydrocarbon distribution. Current production occurs mainly in traps associated with shelf mini-basins. Additional production occurs in traps found above reactived salt sills ('Rohos') on the shelf. Industry exploration is presently focused on identification of traps in the slope mini-basin setting.

  17. An assessment on CO2 geosequestration in deep saline formations in the Taihsi Basin, central Taiwan

    NASA Astrophysics Data System (ADS)

    Cai, Mo-Si; Lin, Andrew T.; Fan, Jhen-Huei

    2015-04-01

    Geological storage of carbon dioxide (CO2) is to inject and store a large amount of anthropogenic CO2 in deep and sealed porous rocks in order to mitigate the aggravated threat of global climate changes. Borehole and reflection seismic data are used to understand the spatial distribution of suitable CO2 reservoirs and cap rocks in the Taihsi Basin, central Taiwan, where the level of seismicity is low. The Taihsi Basin was a rift basin during the Paleocene to Eocene, followed by a phase of post-rift subsidence during late Oligocene to late Miocene. The loading of the Taiwan mountain belt since late Miocene has turned the Taihsi Basin into a peripheral foreland basin, with strata gently dipping toward the mountain belts in the east. The coastal plain in central Taiwan (Changhua and Yunlin Counties) and its adjacent offshore areas are close to major CO2 emission sources and no active geological structures are found in these areas, making the study area a favorable CO2 storage site. Spatial distribution of formation thickness and depth for CO2 reservoirs and cap rocks indicates three CO2 storage systems existed in the study area. They are: (1) late Miocene to Pliocene Nanchuang Formation and Kueichulin Formation (reservoirs)-Chinshui Shale (seals) system (hereafter abbreviated as NK-C system), (2) early to middle Miocene Shihti Formation and Peiliao Formation (reservoirs)-Talu Shale (seals) system (SP-T system), (3) early Miocene Mushan Formation (reservoirs)-Piling Shale (seals) system (M-P system). The NK-C system contains multiple layers of porous sandstones from Nanchuang and Kueichulin formations, with total thickness around 210-280 m. In the vicinity of the northern bank of the Jhuoshuei River, reservoir top reaches a depth around 1850 m, with 60 m thick seal formation, the Chinshui Shale. However, the Chinshui Shale becomes sand-prone in the Changhua coastal and nearshore areas due to facies changes. The SP-T system consists of two porous sandstone layers from

  18. Regional analysis of changes in snow pack in mountainous basins in the central Danube region

    NASA Astrophysics Data System (ADS)

    Balint, Gabor; Juričeková, Katarina; Gauzer, Balazs; Hlavčová, Kamila; Kohnová, Silvia; Szolgay, Jan; Zsideková, Beata

    2013-04-01

    Accurate estimation of the volume of water stored in the snow pack and its rate of release is essential to predict the flow during the snowmelt period. In mountainous drainage basins water stored in the snow pack represents an important component of the water budget. Two modelling tools are compared. The first, HOLV snowmelt model is developed by the Hungarian National Hydrological Forecasting Service (VITUKI NHFS) for regional assessment of snow accumulation and ablation of the central Danube. The model originates from the early 80's and it is under continuous development, while its recent distributed version over a grid with 0.1 degree resolution is in use. The snowmelt model has a flexible structure; it is able to change its own structure in function of data availability. In case when only precipitation and air temperature data are available temperature index method is used. When also other data are accessible (cloudiness, dew point, wind speed) using of energy balance model is to be preferred. If there are suitable data available for calculation of the energy terms, the energy balance method can be applied. The second semi-distributed Hron model, developed at the Slovak University of Technology was applied to a smaller sub-basin to represent spatial distribution of snow cover by simulated snow water equivalent. The upper Hron river basin with an area of 1766 km2 is located in central Slovakia. The conceptual semi-distributed tool applied contains three basic storage components with 15 calibrated parameters, as the flow routing component the cascade of linear reservoirs is used as opposed to the original simple triangular routing function. The snow sub-model uses the temperature index (degree-day) method for snow accumulation and snowmelt calculations. Uncertainty of model parameters was reduced by multi-calibration on the mean daily discharges in the basin outlet and measured stations data of snow water equivalent. Changes in the model parameters during the

  19. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2003-11-11

    The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.

  20. BASIN ANALYSIS AND PETROLEUM SYSTEM CHARACTERIZATION AND MODELING, INTERIOR SALT BASINS, CENTRAL AND EASTERN GULF OF MEXICO

    SciTech Connect

    Ernest A. Mancini

    2003-09-11

    The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.

  1. Slab roll-back and trench retreat as controlling factor for basin subsidence in southern Central America

    NASA Astrophysics Data System (ADS)

    Brandes, Christian; Winsemann, Jutta

    2015-04-01

    Slab roll-back and trench retreat are important factors for basin subsidence, magma generation and volcanism in arc-trench systems. Based on the sedimentary and tectonic record of the southern Central American island-arc we conclude that repeated phases of slab roll-back and trench retreats occurred the arc-trench system since the Late Cretaceous. These trench retreats were most probably related to the subduction of oceanic plateaus and seamounts and effected both the fore-arc and back-arc evolution. We used numerical basin modelling techniques to analyse the burial history of fore-arc and back-arc basins in Central America and combined the results with field data of the sedimentological evolution of the basin-fills. From the basin models, geohistory curves were extracted for the fore-arc and back-arc basins to derive the subsidence evolution. The Sandino Fore-arc Basin is characterized by low subsidence during the first 40 Myr. Since the Late Cretaceous the basin has a linear moderate subsidence with a phase of accelerated subsidence in the Oligocene. In the North and South Limón Back-arc Basin, subsidence started at approximately the same time as in the Sandino Fore-arc Basin. The North and South Limón Basins show a linear subsidence trend in the Paleocene and Eocene. Evidence for trench retreats is given by pulses of uplift in the outer-arc area, followed by subsidence in both the fore-arc and back-arc basins. The first slab roll-back probably occurred during the Early Paleocene. This is indicated by the collapse of carbonate platforms, and the re-deposition of large carbonate blocks into deep-water turbidites. A new pulse of uplift or decreased subsidence, respectively during the Late Eocene is attributed to subduction of rough crust. A subsequent slab detachment and the establishment of a new subduction zone further westward was described by Walther et al. (2000). Strong uplift affected the entire fore-arc area, which led to the deposition of very coarse

  2. LIMNETIC LARVAL FISH IN THE NEARSHORE ZONE OF THE SOUTH SHORE OF THE CENTRAL BASIN OF LAKE ERIE

    EPA Science Inventory

    This report presents the results of a survey of larval fish in the nearshore zone of the central basin of Lake Erie from Conneaut to Sandusky, Ohio. Larval fish were sampled at 10 transects during each of 8 cruise periods between 2 May and 9 August 1978. Concentrations of fish la...

  3. Long-term agroecosystem research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed weather data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of weather, particularly precipitation, is fundamental to interpreting watershed and hydrologic processes. The long-term weather record in the Goodwater Creek Experimental Watershed, which is the core of the Central Mississippi River Basin (CMRB) node of the Long-Term Agro-ecosystem Resear...

  4. Pythium Species Associated with Damping-off of Pea in Certified Organic Fields in the Columbia Basin of Central Washington

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A survey of Pythium species in organic vegetable production areas of the semi-arid Columbia Basin of central Washington was carried out in the fall of 2009 to identify species associated with damping-off during early spring planting. Isolates (n = 305) baited from soil sampled from 37 certified orga...

  5. UTILIZATION OF IN-STREAM STRUCTURES FOR WET MEADOW STABILIZATION IN THE CENTRAL GREAT BASIN: A PROCESS-ORIENTED APPROACH

    EPA Science Inventory

    Wet meadows, riparian corridor phreatophyte assemblages, and high-altitude spring-fed aspen meadows all serve as important habitats in the Great Basin of central Nevada. Geomorphic and biotic characterization of the wet meadow complexes demonstrates that most terminate downvalle...

  6. The ant (Hymenoptera: Formicidae) fauna of the cedar glades and xeric limestone prairies of the Central Basin of Tennessee

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ants may be the most thoroughly documented group of insects inhabiting the cedar glades of the Central Basin of Tennessee with two studies conducted in the late 1930s reporting ants found in cedar glades of the region. To compare the ant fauna of modern cedar glades with the lists produced in earlie...

  7. Gravity modeling constraints on the Gatun-Chagres Basin and tectonic evolution of north-central Panama

    NASA Astrophysics Data System (ADS)

    Mynhier, Kelci

    The Oligocene-Miocene collision between Panama and South America significantly influenced ocean currents, global climate, and species diversification. Intraplate deformation of the Panama Block also played an important role in the evolution of this tectonic system, but is not well understood. A high-resolution gravity survey, coupled with geologic observations, was conducted in north-central Panama to better constrain the processes responsible for the Isthmus' modern configuration. Approximately 110 gravity stations were collected from Colon to Nombre de Dios, Panama and merged with existing data. Subsequently, four 2.5-D gravity models were produced to constrain the geometry of the Gatun-Chagres Basin using different sedimentary densities (1.8, 2.0, and 2.2 g/cm 3) to produce a realistic range of basin thicknesses. Overall, models with an average basin density of 2.0 g/cm3 are most consistent with offshore seismic profiles and field evidence, suggesting basin thickness is ~3.0--3.5 km. Previous seismic reflection data and geochemical analyses of Miocene arc volcanic rocks delineate a zone of extension in the Panama Canal Region, and gravity analysis from this study supports this hypothesis. Field evidence of multiple NW-facing normal faults suggests that they separate the basin from uplifted arc basement rocks east of the Canal, resulting in a 60 mGal gravity gradient. Beneath the basin, gravity models indicate ~5--10 km of crustal thinning. 3-D reconstruction of the 2.5-D models show a northward thickening basin and two depocenters that correspond to the Rio Indio and Toro facies of the Chagres Formation. This analysis suggests two directional extension of the Gatun-Chagres Basin; an east-west direction corresponding to the initial formation of the basin, and a modern northwest-southeast direction. To the northeast, gravity modeling indicates that there is a ~150 m-thick, Cretaceous-Holocene sedimentary basin present from Portobelo to Nombre de Dios. Sedimentary

  8. Low-level nocturnal wind maximum over the Central Amazon Basin

    NASA Technical Reports Server (NTRS)

    Greco, Steven; Ulanski, Stanley; Garstang, Michael; Houston, Samuel

    1992-01-01

    A low-level nocturnal wind maximum is shown to exist over extensive and nearly undisturbed rainforest near the central Amazon city of Manaus. Meteorological data indicate the presence of this nocturnal wind maximum during both the wet and dry seasons of the Central Amazon Basin. Daytime wind speeds which are characteristically 3-7 m/s between 300 and 1000 m increase to 10-15 m/s shortly after sunset. The wind-speed maximum is reached in the early evening, with wind speeds remaining high until several hours after sunrise. The nocturnal wind maximum is closely linked to a strong low-level inversion formed by radiational cooling of the rainforest canopy. Surface and low-level pressure gradients between the undisturbed forest and the large Amazon river system and the city of Manaus are shown to be responsible for much of the nocturnal wind increase. The pressure gradients are interpreted as a function of the thermal differences between undisturbed forest and the river/city. The importance of both the frictional decoupling and the horizontal pressure gradient suggest that the nocturnal wind maximum does not occur uniformly over all Amazonia. Low-level winds are thought to be pervasive under clear skies and strong surface cooling and that, in many places (i.e., near rivers), local pressure gradients enhance the low-level nocturnal winds.

  9. A statistical model for estimating stream temperatures in the Salmon and Clearwater River basins, central Idaho

    USGS Publications Warehouse

    Donato, Mary M.

    2002-01-01

    A water-quality standard for temperature is critical for the protection of threatened and endangered salmonids, which need cold, clean water to sustain life. The Idaho Department of Environmental Quality has established temperature standards to protect salmonids, yet little is known about the normal range of temperatures of most Idaho streams. A single temperature standard for all streams does not take into account the natural temperature variation of streams or the existence of naturally warm waters. To address these issues and to help the Idaho Department of Environmental Quality revise the existing State temperature standards for aquatic life, temperature data from more than 200 streams and rivers in the salmon and Clearwater River Basins were collected. From these data, a statistical model was developed for estimating stream temperatures on the basis of subbasin and site characteristics and climatic factors. Stream temperatures were monitored hourly for approximately 58 days during July, August, and September 2000 at relatively undisturbed sites in subbasins in the Salmon and Clearwater River Basins in central Idaho. The monitored subbasins vary widely in size, elevation, drainage area, vegetation cover, and other characteristics. The resulting data were analyzed for statistical correlations with subbasin and site characteristics to establish the most important factors affecting stream temperature. Maximum daily average stream temperatures were strongly correlated with elevation and total upstream drainage area; weaker correlations were noted with stream depth and width and aver-age subbasin slope. Stream temperatures also were correlated with certain types of vegetation cover, but these variables were not significant in the final model. The model takes into account seasonal temperature fluctuations, site elevation, total drainage area, average subbasin slope, and the deviation of daily average air temperature from a 30-year normal daily average air temperature

  10. 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

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

    USGS Publications Warehouse

    Hatzell, H.H.

    1996-01-01

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

  12. Structural subprovinces of the Central Basin Platform, west Texas: Strike-slip bounded crustal blocks

    SciTech Connect

    Gardiner, W.B. )

    1990-05-01

    The Central Basin platform (CBP) of west Texas is composed of six structural blocks, which moved independently during the Ouachita orogeny. As the South American plate collided with North America the Wasson uplift on the northwestern shelf of the Permian basin acted as a buttress against which the CBP was compressed. Shear forces transmitted through the crust resulted in buckling, uplifting, and faulting of the greater CBP. Although the platform is dominated by vertical movement, it did not however, uplift as a single tectonic unit. Rather, it splintered into six megablocks, which moved simultaneously along oblique-slip fault systems. A tectonic model for formation of the CBP is useful for predicting the orientation and spacing of fault systems. The three structurally highest blocks on the CBP, the Eunice high, the Sand Hills high, and the Fort Stockton uplift, show three distinct positive gravity and magnetic anomalies. These county-sized blocks (35 x 80 km) share similar characteristics: (1) they are bounded by strike-slip faults that involve basement uplift; (2) they have maximum structural deformation along their margins where bends in the strike-slip fault system enhance compressions; and (3) their oil is trapped in high-angle fault structures (R-shears ) along the clock boundaries, but toward the center of the blocks, oil tends to accumulate at unconformity and fold traps. Strike-slip fault systems in west Texas are subtle, with only about 3-7 km of offset and commonly may be overlooked. However, detailed regional mapping indicates that these individual fault segments are parts of through-going systems, which are distributed in logical patterns based upon models for strike-slip tectonics.

  13. A key continental archive for the last 2 Ma of climatic history of the central Mediterranean region: A pilot drilling in the Fucino Basin, central Italy

    NASA Astrophysics Data System (ADS)

    Giaccio, B.; Regattieri, E.; Zanchetta, G.; Wagner, B.; Galli, P.; Mannella, G.; Niespolo, E.; Peronace, E.; Renne, P. R.; Nomade, S.; Cavinato, G. P.; Messina, P.; Sposato, A.; Boschi, C.; Florindo, F.; Marra, F.; Sadori, L.

    2015-12-01

    An 82 m long sedimentary succession was retrieved from the Fucino Basin, the largest intermountain tectonic depression of the central Apennines. The basin hosts a succession of fine-grained lacustrine sediments (ca. 900 m-thick) possibly continuously spanning the last 2 Ma. A preliminary tephrostratigraphy study allows us to ascribe the drilled 82 m long record to the last 180 ka. Multi-proxy geochemical analyses (XRF scanning, total organic/inorganic carbon, nitrogen and sulfur, oxygen isotopes) reveal noticeable variations, which are interpreted as paleohydrological and paleoenvironmental expressions related to classical glacial-interglacial cycles from the marine isotope stage (MIS) 6 to present day. In light of the preliminary results, the Fucino sedimentary succession is likely to provide a long, continuous, sensitive, and independently dated paleoclimatic archive of the central Mediterranean area.

  14. Water Balance of the San Simon Groundwater Basin, El Salvador, Central America

    NASA Astrophysics Data System (ADS)

    Sullivan, M.; Lopez, D. L.; Matus, A.

    2008-05-01

    The Berlin hydrothermal field in El Salvador, Central America is located in the San Simon River Basin on the northwest slope of the Berlin-Tecapa volcanic complex, in the eastern portion of the country. This hydrothermal field, which has been exploited since 1992, is a liquid-dominated system governed by faults and caldera structures allowing infiltration and transport of meteoric fluids. San Simon River is a tributary of the Lempa River, the largest river in the country. Geophysical studies have found that the Berlin field is composed of three aquifers (Shallow, Intermediate, Deep). Exploitation involves the removal of hot fluids from the geothermal reservoir (deep aquifer) and re-injection of lower temperature fluids. This study analyzes the surficial hydrology and groundwater storage change (since exploitation) in the hydrothermal reservoir to produce a water budget. Field monitoring of springs, fumarolic activity, domestic wells, tributaries to the San Simon River, and meteorological data provide constraints on the hydrology. Springs occur in the system close to fault zones or at contacts between different lithologies. The water balance for the San Simon groundwater basin (July 2004 - June 2005) indicates that 2.51 - 3.46 E7 m3/yr of water are infiltrated to the ground, 1.30 - 1.45E7 m3/yr comprises the overland flow, 5.74 E6 m3/yr form the base flow of the San Simon River, and 1.54 E5 m3/yr is released thru the evaporation of Alegria Lake. The shallow aquifer is affected by pumping of 4.78 E6 m3/yr by the national water company. To complete the water balance of the San Simon Basin, a correlation between the composition of the fumarolic gases and the diffuse flux of soil CO2 was performed. The flux of water released from fumarolic areas was estimated at 1.48 E5 m3/yr. An analysis of the increase in chloride concentration with time in the deep aquifer and the net mass withdrawn from this aquifer allow an estimation of the decrease in storage in the hydrothermal

  15. Global Climate Change and Sedimentation Patterns in the Neogene Baringo Basin, Central Kenya Rift

    NASA Astrophysics Data System (ADS)

    Deino, A. L.; Kingston, J. D.; Wilson, K. E.; Hill, A.

    2010-12-01

    The Tugen Hills are part of a ~100 km N-S tilted fault block, just west of Lake Baringo within the Central Kenyan Rift Valley. Sediments exposed in this block span the last 16 Ma and have yielded abundant and diverse fossil assemblages including a number of hominoid and hominid specimens. Much research has also focused on documenting the paleoecology of the succession through analyses of fossil floral, faunal, and biogeochemical proxies. Data from the Tugen Hills have revealed a complex evolutionary history of ecosystems characterized by spatial and temporal heterogeneity with no clear evidence of any long-term trends. While these studies suggest that the patterns of heterogeneity may be shifting at short time-scales (104-105 ka), limited temporal resolution has until now generally precluded assessments of environmental change at these scales. Recently published investigations in the Baringo Basin have provided evidence of orbitally mediated environmental change over periods which include hominid fossil localities (Deino et al., 2006; Kingston et al., 2007). The Baringo data represent the only empirical evidence for significant local environmental shifts that can directly be correlated with insolation patterns in equatorial Africa. Sedimentation patterns in the Baringo Basin between ca. 2.70 and 2.55 Ma, controlled by climatic factors, provide a detailed paleoenvironmental record including a sequence of diatomites that record rhythmic cycling of major freshwater lake systems consistent with ~23 kyr Milankovitch precessional periodicity modulated by eccentricity. The timing of the paleolakes most closely approximates insolation maximum for the June/July 30○N insolation curve, suggesting that precipitation patterns in the region are controlled by the African monsoon system. More recent fieldwork has identified older sequences that similarly demonstrate rhythmic cycling of freshwater lake systems. Preliminary 40Ar/39Ar dating of intercalated tephra reveals that

  16. Thermochronology of Upper Cretaceous and Paleocene Deposits in the Central Cordilleran Foreland Basin

    NASA Astrophysics Data System (ADS)

    Painter, C. S.; Carrapa, B.; DeCelles, P. G.

    2011-12-01

    Since the mid-1980's the significance of coarse-grained fluvial deposits in distal foreland basins has been hotly debated. In one school of thought such deposits represent the stratigraphic signature of tectogenic topographic rejuvenation in the thrust belt during episodes of thrust propagation. More recently such deposits have been interpreted to indicate thrust belt tectonic quiescence and erosionally driven isostatic rebound. One way to address this issue is to investigate the time span between source exhumation and sedimentation (i.e. lag time); coarse sediment produced and deposited during a period of rapid thrust propagation should exhibit short lag times, whereas coarse sediment produced by post-tectonic isostatic rebound should have longer lag times. We sampled coarse-grained proximal units in the Sevier thrust belt in Utah and their distal equivalents up to 300 km east of the thrust front, and generated detrital apatite fission track (AFT) and zircon (U-Th)/He (ZHe) ages. In the proximal foreland, the Campanian Price River Formation and the Maastrichtian to Paleocene North Horn Formation in the Charleston-Nebo salient of north-central Utah were sampled in order to, (1) identify the thermochronometer that most effectively records the source exhumation and, (2) measure lag times in foreland basin units of the proximal part of the foreland basin. ZHe ages from the Price River and North Horn Formations, as well as their distal equivalents, are discordant, indicating that the system was not fully reset. This suggests that these strata never experienced T> ~180 °C; or, it could be that α-damage has contributed to He retention. AFT ages from these samples appear to be fully reset and show a consistent younging up-section. AFT cooling ages for the upper Campanian Price River Formation are 79.8 ± 6.3 Ma in the lower part of the formation and 74.5 ± 6.4 Ma higher up in the section. The Maastrichtian to Paleocene North Horn Formation, which is separated from the

  17. Do manganese nodules grow or dissolve after burial? Results from the Central Indian Ocean Basin

    NASA Astrophysics Data System (ADS)

    Pattan, J. N.; Parthiban, G.

    2007-07-01

    Fifty buried manganese nodules at different depth intervals were recovered in 12 sediment cores from the Central Indian Ocean Basin (CIOB). A maximum of 15 buried nodules were encountered in one sediment core (AAS-22/GC-07) and the deepest nodule was recovered at 5.50 m below seafloor in core AAS-04/GC-5A. Approximately 80% of the buried nodules are small in size (˜2 cm diameter) in contrast to the Atlantic Ocean and Peru Basin (Pacific Ocean) where the majority of the buried nodules are large, ˜8 cm and >6 cm, respectively. Buried nodule size decreases with core depth and this distribution appears to be similar to the phenomenon of "Brazil Nut Effect". Buried nodules exhibit both smooth and rough surface textures and are ellipsoidal, elongated, rounded, sub rounded, irregular and polynucleated. Buried nodules from siliceous ooze are enriched in Mn, Cu, Ni, Zn, Mo, Ga, V and Rb whereas those from red clay are enriched in Fe, Co, Ti, U, Th, Y, Cr, Nb and Rare Earth Elements (REE). Buried nodules from siliceous ooze suggest their formation under hydrogenetic, early digenetic and diagenetic processes whereas those from red clay are of hydrogenetic origin. REE are enriched more than 1.5 times in buried nodules from red clay compared to siliceous ooze. However, the mode of incorporation of REE into buried nodules from both sedimentary environments is by a single authigenic phase consisting of Fe-Ti-P. Shale-normalized REE patterns and Ce anomalies suggest that nodules from siliceous ooze formed under more oxidizing conditions than those from red clay. Nodules buried at depths between 1.5 and 2.5 m are diagenetic (Mn/Fe ratio 10-15), formed in highly oxic environments (large positive Ce anomalies) and record aeolian dust (high Eu anomalies). Chemical composition, surface texture and morphology of buried nodules are similar to those of surface nodules from the same basin. Furthermore, buried nodule compositions do not exhibit any distinct patterns within the core depth

  18. Factors affecting water quality and net flux of solutes in two stream basins in the Quabbin Reservoir drainage basin, central Massachusetts,1983-85

    USGS Publications Warehouse

    Rittmaster, R.L.; Shanley, J.B.

    1995-01-01

    The factors that affect stream-water quality were studied at West Branch Swift River (Swift River), and East Branch Fever Brook (Fever Brook), two forested watersheds that drain into the Quabbin Reservoir, central Massachusetts, from December 1983 through August 1985. Spatial and temporal variations of chemistry of precipitation, surface water; and ground water and the linkages between chemical changes and hydrologic processes were used to identify the mechanisms that control stream chemistry. Precipitation chemistry was dominated by hydrogen ion (composite p.H 4.23), sulfate, and nitrate. Inputs of hydrogen and nitrate from pre- cipitation were almost entirely retained in the basins, whereas input of sulfate was approximately balanced by export by streamflow draining the basins. Both streams were poorly buffered, with mean pH near 5.7, mean alkalinity less than 30 microequivalents per liter, and sulfate concen- trations greater than 130 microequivalents per liter. Sodium and chloride, derived primarily from highway deicing salts, were the dominant solutes at Fever Brook. After adjustments for deicing salts, fluxes of base cations during the 21-month study were 2,014 and 1,429 equivalents per hectare in Swift River and Fever Brook, respectively. Base cation fluxes were controlled primarily by weathering of hornblende (Fever Brook) and plagioclase (Swift River). The overall weathering rate was greater in the Swift River Basin because easily weathered gabbro underlies one subbasin which comprises 11.2 percent of the total basin area but contributed about 77 percent of the total alkalinity. Alkalinity export was nearly equal in the two basins, however, because some alkalinity was generated in wetlands in the Fever Brook Basin through bacterial sulfate reduction coupled with organic-carbon oxidation.

  19. Regional implications of new chronostratigraphic and paleogeographic data from the Early Permian Darwin Basin, east-central California

    USGS Publications Warehouse

    Stevens, Calvin H.; Stone, Paul; Magginetti, Robert T.

    2015-01-01

    The Darwin Basin developed in response to episodic subsidence of the western margin of the Cordilleran continental shelf from Late Pennsylvanian (Gzhelian) to Early Permian (late Artinskian) time. Subsidence of the basin was initiated in response to continental truncation farther to the west and was later augmented by thrust emplacement of the Last Chance allochthon. This deep-water basin was filled by voluminous fine-grained siliciclastic turbidites and coarse-grained limestone-gravity-flow deposits. Most of this sediment was derived from the Bird Spring carbonate shelf and cratonal platform to the northeast or east, but some came from an offshore tectonic ridge (Conglomerate Mesa Uplift) to the west that formed at the toe of the Last Chance allochthon. At one point in the late Artinskian the influx of extrabasinal sediment was temporarily cut off, resulting in deposition of a unique black limestone that allows precise correlation throughout the basin. Deep-water sedimentation in the Darwin Basin ended by Kungurian time when complex shallow-water to continental sedimentary facies spread across the region. Major expansion of the Darwin Basin occurred soon after the middle Sakmarian emplacement of the Last Chance allochthon. This tectonic event was approximately coeval with deformation in northeastern Nevada that formed the deep-water Dry Mountain Trough. We herein interpret the two basins to have been structurally continuous. Deposition of the unique black limestone is interpreted to mark a eustatic sea level rise that also can be recognized in Lower Permian sections in east-central Nevada and central Arizona.

  20. Central magnetic anomalies of Nectarian-aged lunar impact basins: Probable evidence for an early core dynamo

    NASA Astrophysics Data System (ADS)

    Hood, Lon L.

    2011-02-01

    A re-examination of all available low-altitude LP magnetometer data confirms that magnetic anomalies are present in at least four Nectarian-aged lunar basins: Moscoviense, Mendel-Rydberg, Humboldtianum, and Crisium. In three of the four cases, a single main anomaly is present near the basin center while, in the case of Crisium, anomalies are distributed in a semi-circular arc about the basin center. These distributions, together with a lack of other anomalies near the basins, indicate that the sources of the anomalies are genetically associated with the respective basin-forming events. These central basin anomalies are difficult to attribute to shock remanent magnetization of a shocked central uplift and most probably imply thermoremanent magnetization of impact melt rocks in a steady magnetizing field. Iterative forward modeling of the single strongest and most isolated anomaly, the northern Crisium anomaly, yields a paleomagnetic pole position at 81° ± 19°N, 143° ± 31°E, not far from the present rotational pole. Assuming no significant true polar wander since the Crisium impact, this position is consistent with that expected for a core dynamo magnetizing field. Further iterative forward modeling demonstrates that the remaining Crisium anomalies can be approximately simulated assuming a multiple source model with a single magnetization direction equal to that inferred for the northernmost anomaly. This result is most consistent with a steady, large-scale magnetizing field. The inferred mean magnetization intensity within the strongest basin sources is ˜1 A/m assuming a 1-km thickness for the source layer. Future low-altitude orbital and surface magnetometer measurements will more strongly constrain the depth and/or thicknesses of the sources.

  1. Conservation Effects Assessment Project-Wetlands assessment in California's Central Valley and Upper Klamath River Basin

    USGS Publications Warehouse

    2011-01-01

    Executive Summary-Ecosystem Services Derived from Wetlands Reserve Program Conservation Practices in California's Central Valley and Oregon's Upper Klamath River Basin. The Wetlands Reserve Program (WRP) is one of several programs implemented by the U.S. Department of Agriculture (USDA). Since the WRP's inception in 1990, it has resulted in the restoration of approximately 29,000 hectares in California's Central Valley (CCV) and roughly 12,300 hectares in Oregon's Upper Klamath River Basin (UKRB). Both the CCV and UKRB are agricultural dominated landscapes that have experienced extensive wetland losses and hydrological alteration. Restored habitats in the CCV and UKRB are thought to provide a variety of ecosystem services, but little is known about the actual benefits afforded. The U.S. Geological Survey (USGS) California Cooperative Fish and Wildlife Unit in collaboration with the USDA Natural Resources Conservation Service surveyed 70 WRP sites and 12 National Wildlife Refuge sites in the CCV, and 11 sites in the UKRB to estimate ecosystem services provided. In the CCV, sites were selected along three primary gradients; (1) restoration age, (2) management intensity, and (3) latitude (climate). Sites in the UKRB were assessed along restoration age and management intensity gradients where possible. The management intensity gradient included information about the type and frequency of conservation practices applied at each site, which was then ranked into three categories that differentiated sites primarily along a hydrological gradient. Information collected was used to estimate the following ecosystem services: Soil and vegetation nutrient content, soil loss reduction, floodwater storage as well as avian, amphibian, fish, and pollinator use and habitat availability. Prior to this study, very little was known about WRP habitat morphology in the CCV and UKRB. Therefore in this study, we described these habitats and related them to ecosystem services provided. Our

  2. Controls on cross-sectional geometry of extensional basins, east-central Nevada -- A seismic-stratigraphic approach

    SciTech Connect

    Potter, C.J.; Grow, J.A.; Miller, J.J. )

    1993-04-01

    A 110-km regional seismic profile in east-central Nevada crosses Neogene east-tilted half-grabens in (from west to east) Railroad Valley (RRV), White River Valley, Cave Valley (CV), Muleshoe Valley and Lake Valley. Variations in the internal architecture of these basins may be related to two factors: (1) differences in structural evolution and (2) position of cross section (i.e., the seismic profile) with respect to major depocenters, accommodation zones, and other along-strike transitions in basin geometry. A detailed grid of seismic data in Railroad Valley and proprietary data from other basins show that without adequate three-dimensional seismic control, one should carefully consider factor (2) before generalizing about factor (1). As illustrations, the authors compare cross section derived from the seismic data across RRV (latitude of Grant Canyon) and CV (latitude of Sidehill Pass). In summary, data from RRV and CV illustrate the complexity of broad basin-bounding extensional fault zones and suggest that listric faulting and stratal rotation are characteristic of basin depocenters, whereas translation above planar bounding faults is characteristic of parts of extensional basins that are removed from the depocenter.

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

    NASA Astrophysics Data System (ADS)

    Feng, Youliang; Jiang, Shu; Wang, Chunfang

    2015-06-01

    The Lower Jurassic Junggar Basin is a low-accommodation basin in northwestern China. Because of low subsidence rates and a warm, wet climate, deposits of the Central subbasin of the Junggar Basin formed from fluvial, deltaic, shallow lake facies. Sequence stratigraphy and sedimentary systems of the Lower Jurassic members of the Sangonghe Formation (J1s) were evaluated by observing cores, interpreting wireline logs and examining seismic profiles. Two third-order sequences were recognized in the strata. The distribution of the sedimentary systems in the systems tracts shows that tectonic movement, paleorelief, paleoclimate and changes in lake level controlled the architecture of individual sequences. During the development of the lowstand systems tract (LST), the intense structural movement of the basin resulted in a significant fall in the water level in the lake, accompanied by rapid accommodation decrease. Braided rivers and their deltaic systems were also developed in the Central Junggar Basin. Sediments carried by braided rivers were deposited on upward slopes of the paleorelief, and braid-delta fronts were deposited on downward slopes. During the transgressive systems tract (TST), the tectonic movement of the basin was quiescent and the climate was warm and humid. Lake levels rose and accommodation increased quickly, shoal lines moved landward, and shore- to shallow-lake deposits, sublacustrine fans and deep-lake facies were deposited in shallow- to deep-lake environments. During the highstand systems tract (HST), the accommodation no longer increased but sediment supply continued, far exceeding accommodation. HST deposits slowly formed in shallow-lake to meandering river delta-front environments. Relatively low rates of structural subsidence and low accommodation resulted in coarse-grained successions that were fining upward. Deposits were controlled by structural movement and paleorelief within the LST to TST deposits in the Central subbasin. Fine- to medium

  4. Central Basin and Range Ecoregion: Chapter 20 in Status and trends of land change in the Western United States--1973 to 2000

    USGS Publications Warehouse

    Soulard, Christopher E.

    2012-01-01

    This chapter has been modified from original material published in Soulard (2006), entitled “Land-cover trends of the Central Basin and Range Ecoregion” (U.S. Geological Survey Scientific Investigations Report 2006–5288). The Central Basin and Range Ecoregion (Omernik, 1987; U.S. Environmental Protection Agency, 1997) encompasses approximately 343,169 km² (132,498 mi2) of land bordered on the west by the Sierra Nevada Ecoregion, on the east by the Wasatch and Uinta Mountains Ecoregion, on the north by the Northern Basin and Range and the Snake River Basin Ecoregions, and on the south by the Mojave Basin and Range and the Colorado Plateaus Ecoregions (fig. 1). Most of the Central Basin and Range Ecoregion is located in Nevada (65.4 percent) and Utah (25.1 percent), but small segments are also located in Idaho (5.6 percent), California (3.7 percent), and Oregon (0.2 percent). Basin-and-range topography characterizes the Central Basin and Range Ecoregion: wide desert valleys are bordered by parallel mountain ranges generally oriented northsouth. There are more than 33 peaks within the Central Basin and Range Ecoregion that have summits higher than 3,000 m (10,000 ft), but valleys in the ecoregion are also high, most having elevations above 1,200 m (4,000 ft) (Grayson, 1993).

  5. 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

  6. The role of inherited structures in the evolution of the Meknassy Basin, Central Tunisia, based on geological-geophysical transects

    NASA Astrophysics Data System (ADS)

    Haji, Taoufik; Zouaghi, Taher; Boukadi, Noureddine

    2014-08-01

    This paper uses seismic data, well data, and surface geologic data to present a detailed description of the Meknassy Basin in the Atlas fold and thrust belt of central Tunisia. These data reveal that the Meknassy Basin is bounded by major faults, along which Triassic evaporites have been intruded. The anticlines and synclines of the basin are delimited by two N-S main faults (the North-South Axis and the Sidi Ali Ben Oun fault) and are subdivided by associated N120° and N45° trending fault-related anticlines. The Meknassy Basin is characterized by brittle structures associated with a deep asymmetric geometry that is organized into depressions and uplifts. Halokinesis of Triassic evaporites began during the Jurassic and continued during the Cretaceous period. During extensional deformation, salt movement controlled the sediment accumulation and the location of pre-compressional structures. During compressional deformation, the remobilization of evaporites accentuated the folded uplifts. A zone of decollement is located within the Triassic evaporites. The coeval strike-slip motion along the bounding master faults suggests that the Meknassy Basin was initiated as a pull-apart basin with intrusion of Triassic evaporites. The lozenge structure of the basin was caused by synchronous movements of the Sidi Ali Ben Oun fault and the North-South Axis (sinistral wrench faults) with movement of NW-SE first-order dextral strike-slip faults. Sediment distribution and structural features indicate that a major tectonic inversion has occurred at least since Late Cretaceous and Cenozoic. The transpressional movements are marked by reverse faults and folds associated with unconformities and with remobilization of Triassic evaporites. The formation of different structural features and the evolution of the Meknassy Basin and its neighboring uplifts have been controlled by conjugate dextral and sinistral strike-slip movements and thrust displacement.

  7. Scyphozoa in the Bornholm Basin (central Baltic Sea) The role of advection

    NASA Astrophysics Data System (ADS)

    Barz, Kristina; Hinrichsen, Hans-Harald; Hirche, Hans-Jürgen

    2006-04-01

    The usual absence of ephyrae and late appearance of medusae of the Scyphozoa Aurelia aurita and Cyanea capillata in the Bornholm Basin (BB; central Baltic Sea) indicate that these species are not strobilating in the region and their presence depends on advection. To study their potential origin we compared drift from historically known strobilation areas derived from a circulation model with spatial distributions observed during 19 cruises in the BB during 2002 and 2003. The model results are in good accordance with the field observations. According to the model results inter-annual differences in the timing of first appearance and life stage at appearance of A. aurita were clearly related to differences in the hydrodynamic regime during the investigation periods. During the stagnation regime in 2002 young medusae occurred first in June in the BB. In contrast, in 2003 fast transport due to several inflow events advected ephyrae released between January and March in the western Baltic already in April to the BB. Although the Gullmar Fjord (western Sweden) is the nearest known strobilation area for C. capillata, the model did not support advection from there in numbers explaining the occurrence of this species in the BB in 2002 and 2003. If the model works adequately in this regions we have to assume that the Gullmar Fjord is not a main source region of C. capillata in the BB, but other strobilation areas in the Kattegat or the North Sea appear more important. Our results imply that advection and inflow events are critical for the occurrence and distribution of early stages of jellyfish in the central Baltic Sea. They demonstrate the potential of circulation models as tools to study the effect of long-range transport on the spatial composition of these organisms.

  8. Steady contemporary deformation of the central Basin and Range Province, western United States

    NASA Astrophysics Data System (ADS)

    Hammond, William C.; Blewitt, Geoffrey; Kreemer, Corné

    2014-06-01

    We use data from western U.S. GPS networks to estimate the rate, pattern, and style of tectonic deformation of the central Basin and Range Province (BRP). Previous geodetic investigations have found the crust of eastern Nevada and western Utah to act as a rigid microplate, with zero deformation rates to within measurement uncertainty. Observed transients in GPS time series have led others to propose a megadetachment model, predicting that the central BRP behaves as a microplate, but with time-varying translation. Here we reassess these hypotheses, benefiting from a significant increase in GPS stations and time span, and innovations in analysis techniques. Our results show that the BRP crust deforms everywhere and all the time. In a group of 24 stations between longitude -113.5° and -116.8°, we find strain rates of 1.9 ± 0.2 × 10-9 yr-1 extension directed N55°W and 2.2 ± 0.2 × 10-9 yr-1 contraction directed N35°E, inconsistent with microplate behavior. The linearity of time series of strain from GPS station triplets is inconsistent with episodic translation of quasi-rigid domains. One exception is station EGAN that exhibits nonlinear motion not found in adjacent stations. The dominant signal in Nevada is distributed shear consistent with Pacific/North America relative plate motion, suggesting that stresses are transmitted through the lithosphere at least 800 km from the plate boundary. The observed active extension is consistent with earthquake focal mechanisms and is in agreement with integrated rates estimated from earthquake geology. Our results do not support the proposed megadetachment in the BRP.

  9. Spatial analysis from remotely sensed observations of Congo basin of East African high Land to drain water using gravity for sustainable management of low laying Chad basin of Central Africa

    NASA Astrophysics Data System (ADS)

    Modu, B.; Herbert, B.

    2014-11-01

    The Chad basin which covers an area of about 2.4 million kilometer square is one of the largest drainage basins in Africa in the centre of Lake Chad .This basin was formed as a result of rifting and drifting episode, as such it has no outlet to the oceans or seas. It contains large area of desert from the north to the west. The basin covers in part seven countries such as Chad, Nigeria, Central African Republic, Cameroun, Niger, Sudan and Algeria. It is named Chad basin because 43.9% falls in Chad republic. Since its formation, the basin continues to experienced water shortage due to the activities of Dams combination, increase in irrigations and general reduction in rainfall. Chad basin needs an external water source for it to be function at sustainable level, hence needs for exploitation of higher east African river basin called Congo basin; which covers an area of 3.7 million square km lies in an astride the equator in west-central Africa-world second largest river basin after Amazon. The Congo River almost pans around republic of Congo, the democratic republic of Congo, the Central African Republic, western Zambia, northern Angola, part of Cameroun, and Tanzania. The remotely sensed imagery analysis and observation revealed that Congo basin is on the elevation of 275 to 460 meters and the Chad basin is on elevation of 240 meters. This implies that water can be drained from Congo basin via headrace down to the Chad basin for the water sustainability.

  10. Future glaciation and river flow in the Vakhsh and Panj drainage basins, Central Asia

    NASA Astrophysics Data System (ADS)

    Hoelzle, Martin; Hagg, Wilfried; Wagner, Stephan

    2010-05-01

    Central Asia is well known as an area of substantial water problems mainly caused by climate change and careless consumption of water resources. As in other parts of the globe where high mountains are surrounded by arid and semi-arid zones, snow and glacier melt are major contributors to runoff and important resources for agriculture in the lowlands. The FAO-UNESCO has started a "Climate Impact Study on Streamflow" to estimate future discharge in the catchments of the rivers Vakhsh (39,100 km2) and Panj(114,000 km2), the two tributaries of Amu Darya river. According to the World Glacier Inventory (WGI) prepared in the mid 20th century, the Panj and Vakhsh catchments have glacier covers of 3,913 km2 and 3,675 km2, respectively. A new inventory was conducted in 2003 within the frame of the GLIMS project. We used a simple parametrization scheme based on steady state conditions to infer the ice volumes for the two different time periods in the past and to extrapolate future changes. The resulting volumes for the WGI are 170-200 km3 for the Panj catchment and 200-240 km3 for the Vakhsh catchment. From the mid of the 20th century to 2003, an area (volume) decrease of 8.2% (10.5%) for the Panj and 7.5% (4.1%) for the Vakhsh catchment was determined. A comparison of two digital elevation models (SRTM of 2001 and Aster 2008) show for the glacier areas a mean mass change of -0.61 m a-1 for the Vakhsh and -0.81 m a-1 for the Panj. Regional climate simulations project a warming of 1.8°C-2.9°C until 2050, while it remains unclear if and in what direction precipitation will change. Assuming a temperature increase of 2°C until 2050 and no change in precipitation, the ice reserves in the two catchments will decline at an accelerated rate in comparison to the past with total volume reduction of 75.5% for the Panj basin and of 53% for the Vakhsh basin. To simulate present-day and future runoff, the HBV-ETH hydrological model was set up in the two sub-basins of Abramov (56 km

  11. Rainfall and land use empirically coupled to forecast landslides in the Esino river basin, central Italy

    NASA Astrophysics Data System (ADS)

    Gioia, E.; Carone, T.; Marincioni, F.

    2015-06-01

    A coupled empirical approach to highlight relationships between rainfall, vegetation segmentation, and landslide occurrence is discussed. To reveal such links, two important rainfall events, which occurred over the Esino river basin in central Italy in November 2013 and May 2014, were analysed. The correlation between rainfall and landslides was evaluated by applying an intensity-duration (ID) threshold method, whereas the correlation between vegetation segmentation and landslides was investigated using morphological spatial pattern analysis (MSPA). This coupled approach represents an attempt to find both timing and location of landslide occurrence through an empirical (black box) analysis. Results showed: (i) the ID minimum threshold proposed in a previous study (Gioia et al., 2015) to be verified as an effective equation to assess the rainfall conditions likely to trigger landslides in the study area ("when"), and (ii) the core areas and the fragmented vegetation structures defined by the MSPA to be the most affected by slope failures ("where"). These encouraging findings prompt additional testing and the application of such a coupled empirical approach so that it is possible to achieve an integrated basis for landslide forecasting.

  12. Selenium Concentrations in Middle Pennsylvanian Coal-Bearing Strata in the Central Appalachian Basin

    USGS Publications Warehouse

    Neuzil, Sandra G.; Dulong, Frank T.; Cecil, C. Blaine; Fedorko, Nick; Renton, John J.; Bhumbla, D.K.

    2007-01-01

    Introduction This report provides the results of a reconnaissance-level investigation of selenium (Se) concentrations in Middle Pennsylvanian coal-bearing strata in the central Appalachian basin. Bryant and others (2002) reported enrichments of Se concentrations in streams draining areas disturbed by surface mining relative to Se concentrations in streams that drain undisturbed areas; the study was conducted without the benefit of data on Se concentrations in coal-bearing strata prior to anthropogenic disturbance. Thus, the present study was conducted to provide data on Se concentrations in coal-bearing strata prior to land disturbance. The principal objectives of this work are: 1) determine the stratigraphic and regional distribution of Se concentrations in coal-bearing strata, 2) provide reconnaissance-level information on relations, if any, between Se concentrations and lithology (rock-type), and 3) develop a cursory evaluation of the leachability of Se from disturbed strata. The results reported herein are derived from analyses of samples obtained from three widely-spaced cores that were collected from undisturbed rock within a region that has been subjected to extensive land disturbance principally by either coal mining or, to a lesser extent, highway construction. The focus was on low-organic-content lithologies, not coal, within the coal-bearing interval, as these lithologies most commonly make up the fill materials after coal mining or in road construction.

  13. A new early Oligocene mammal fauna from the Sirt Basin, central Libya: Biostratigraphic and paleobiogeographic implications

    NASA Astrophysics Data System (ADS)

    Coster, Pauline M. C.; Beard, K. Christopher; Salem, Mustafa J.; Chaimanee, Yaowalak; Brunet, Michel; Jaeger, Jean-Jacques

    2015-04-01

    We report the discovery of a new early Oligocene vertebrate fauna from the vicinity of Zallah Oasis in the Sirt Basin of central Libya. The Zallah Incision local fauna has been recovered from the base of a fluvial channel within a rock unit that has been mapped as "Continental and Transitional Marine Deposits." This rock unit has produced fossil vertebrates sporadically since the 1960s, but the Zallah Incision local fauna is the most diverse assemblage of fossil mammals currently known from this unit. In addition to lower vertebrates, the fauna includes an indeterminate sirenian, the anthracothere Bothriogenys, a new species of the hyracoid genus Thyrohyrax, new species of the hystricognathous rodent genera Metaphiomys and Neophiomys, Metaphiomys schaubi, and a new species of the parapithecid primate genus Apidium. The Zallah Incision local fauna from Libya appears to be close in age to Fayum quarries V and G in the Jebel Qatrani Formation of Egypt and the Taqah locality in the Ashawq Formation of Oman. Considered together, these early Oligocene faunas support a modest level of faunal provincialism across the northern part of Afro-Arabia during the early Oligocene.

  14. Flow dynamics and erosion rate of representative karst basin (Upper Aniene River, Central Italy)

    SciTech Connect

    Bono, P.; Percopo, C.

    1996-04-01

    Experimental data refer to a preliminary estimate of suspended solid and solute load of a perennial river. The basin is composed almost entirely of bare mesozoic, highly fractured, karstified carbonate rocks of the central Apennine range. The suspended solid load related to stormflow events in 1991 corresponds to about 14,970 t yr{sup -1}. For the same period the solute load is 60,060 t yr{sup -1} for a mean base flow discharge of 9.4 m{sup 3} s{sup -1}. Based on the mean concentration of Ca + Mg in water, the value of dissolution of carbonate rocks of 37.1 m{sup 3} km{sup -2} (equivalent approximately to 0.04 mm yr{sup -1}) was calculated. Physical and chemical variations that occur during storm events indicate the complex dynamic processes in the karst aquifier and the role undertaken by the epikarst as perched water reservoir and by the major conduits that develop through the vadose and saturated zones of the karst system. 12 refs., 10 figs., 5 tabs.

  15. Mining conditions and deposition in the Amburgy (Westphalian B) coal, Breathitt Group, central Appalachian basin

    SciTech Connect

    Greb, S.F.; Eble, C.F.; Hower, J.C.; Phillips, T.L.

    1996-09-01

    Carbonate concretions called clay balls are rare in the Central Appalachian Basin, but were found in the Amburgy coal overlain by the Kendrick Shale Member. In the study area, the Amburgy coal is 0.7 to 0.9 meters thick, moderate to high in sulfur content, moderate to high in ash yield, and mostly bright clarain, except at the top near the area of coal balls, where durain of limited extent occurs. The coal is co-dominated by lycopod and cordaites; tree spores, with subordinate Calamites. The local durain layer is dominated by Densosporites, produced by the shrubby lycopod Ompbalophloios. Coal balls were encountered where the durain is immediately overlain by a coquinoid hash of broken and whole marine fossils, along a trend of coal thinning. The coal balls contain permineralized cordaites, lycopods, calamites, and ferns. The Amburgy coal accumulated as a succession of planar mires. Local splits in the seam are common, indicating contemporaneous clastic influx. The abundance of Cordaites may indicate brackish mire waters related to a coastal position and initial eustatic rise of the marginal Kendrick seas. Near the end of the Amburgy mires, the high ash-Omphalopbloios association is interpreted as a local area that was being drowned by the Kendrick transgression. Ravinement within this local embayment, rapid inundation by marine waters, and concentration of carbonate-bearing waters within transgressive scours may have contributed to the formation of coal balls and pyritic concretions in the upper part of the coal bed.

  16. Cycle stratigraphy and porosity in Pennsylvanian and Lower Permian shelf limestones, eastern Central Basin Platform, Texas

    SciTech Connect

    Saller, A.H.; Dickson, J.A.D.; Boyd, S.A.

    1994-12-01

    Pennyslvanian and Lower Permian shelfal limestones were studied in core and wireline logs on the eastern side of the Central Basin platform in west Texas. Sixty-three (63) cycles were delineated in the study interval, which includes 200-250 m of Canyon (Missourian), Cisco (Virgilian), and Wolfcamp strata. Four general lithofacies are present: fossiliferous wackestones and packstones, grainstones, phylloid algal boundstones, and shales. These lithologies typically occur in 1-18-m-thick cycles bounded by subaerial exposure surfaces. Grainstones in the upper part of some cycles indicate a shallowing of environments prior to subaerial exposure. Many cycles have subaerial exposure surfaces developed on subtidal fossiliferous wackestones or packstones suggesting rapid falls in sea level. Long-term transgressive intervals (transgressive systems tracts or TST) are dominated by thick (>4 m) cycles, whereas long-term regressive intervals (highstand systems tract or HST) are dominated by thinner cycles. Stable carbon isotope data suggest that thick cycles in TSTs were subjected to short periods of subaerial exposure, whereas thin cycles in the HSTs were subjected to much longer subaerial exposure. Where present, reservoir-grade porosity occurs in the upper part of cycles, 0.3-5 m below subaerial exposure surfaces. Prolonged subaerial exposure apparently reduced matrix porosity by allowing more time for calcite precipitation, which was especially effective in reducing porosity in micritic strata below exposure surfaces.

  17. Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

    NASA Astrophysics Data System (ADS)

    Sobrinho, R. L.; Bernardes, M. C.; Abril, G.; Kim, J.-H.; Zell, C. I.; Mortillaro, J.-M.; Meziane, T.; Moreira-Turcq, P.; Sinninghe Damsté, J. S.

    2015-06-01

    In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as the C : N ratio and the stable isotopic composition of organic carbon (δ13Corg). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the isoprenoid GDGT (iGDGT) crenarchaeol as an indicator of riverine suspended particulate organic matter (SPOM). Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C3 plant-derived OM. However, a downstream increase in C4 macrophyte derived OM contribution was observed along the gradient of increasing open waters, i.e. from upstream to downstream. Accordingly, we attribute temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.

  18. Spatial and seasonal contrasts of sedimentary organic matter in floodplain lakes of the central Amazon basin

    NASA Astrophysics Data System (ADS)

    Sobrinho, R. L.; Bernardes, M. C.; Abril, G.; Kim, J.-H.; Zell, C. I.; Mortillaro, J.-M.; Meziane, T.; Moreira-Turcq, P.; Sinninghe Damsté, J. S.

    2016-01-01

    In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter (SOM) in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Mirituba and Curuai) which have different morphologies, hydrodynamics and vegetation coverages. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as the C : N ratio and the stable isotopic composition of organic carbon (δ13Corg). These results were compared with lignin phenol parameters as an indicator of vascular plant detritus and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the input of soil organic matter (OM) from land to the aquatic settings. We also applied the crenarchaeol as an indicator of aquatic (rivers and lakes) OM. Our data showed that during the RW and FW seasons, the surface sediments were enriched in lignin and brGDGTs in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of allochthonous, C3 plant-derived OM. However, a downstream increase in C4 macrophyte-derived OM contribution was observed along the gradient of increasing open waters - i.e., from upstream to downstream. Accordingly, we attribute the temporal and spatial difference in SOM composition to the hydrological dynamics between the floodplain lakes and the surrounding flooded forests.

  19. Parascolymia (Scleractinia: Lobophylliidae) in the Central Paratethys Sea (Vienna Basin, Austria) and its possible biogeographic implications.

    PubMed

    Reuter, Markus; Wiedl, Thomas; Piller, Werner E

    2015-01-01

    Palaeobiogeographical and palaeodiversity patterns of scleractinian reef corals are generally biased due to uncertain taxonomy and a loss of taxonomic characters through dissolution and recrystallization of the skeletal aragonite in shallow marine limestones. Herein, we describe a fossil lobophylliid coral in mouldic preservation from the early middle Miocene Leitha Limestone of the Central Paratethys Sea (Vienna Basin, Austria). By using grey-scale image inversion and silicone rubber casts for the visualization of the original skeletal anatomy and the detection of distinct micromorphological characters (i.e. shape of septal teeth, granulation of septocostae) Parascolymia bracherti has been identified as a new species in spite of the dissolved skeleton. In the recent era, Parascolymia like all Lobophylliidae is restricted to the Indo-Pacific region, where it is represented by a single species. The new species proves the genus also in the Miocene Mediterranean reef coral province. A review of the spatio-temporal relationships of fossil corals related to Parascolymia indicates that the genus was probably rooted in the Eastern Atlantic‒Western Tethys region during the Paleocene to Eocene and reached the Indo-Pacific region not before the Oligocene. The revealed palaeobiogeographical pattern shows an obvious congruence with that of Acropora and tridacnine bivalves reflecting a gradual equatorwards retreat of the marine biodiversity center parallel to the Cenozoic climate deterioration. PMID:26201071

  20. Parascolymia (Scleractinia: Lobophylliidae) in the Central Paratethys Sea (Vienna Basin, Austria) and its possible biogeographic implications

    PubMed Central

    Reuter, Markus; Wiedl, Thomas; Piller, Werner E.

    2015-01-01

    Palaeobiogeographical and palaeodiversity patterns of scleractinian reef corals are generally biased due to uncertain taxonomy and a loss of taxonomic characters through dissolution and recrystallization of the skeletal aragonite in shallow marine limestones. Herein, we describe a fossil lobophylliid coral in mouldic preservation from the early middle Miocene Leitha Limestone of the Central Paratethys Sea (Vienna Basin, Austria). By using grey-scale image inversion and silicone rubber casts for the visualization of the original skeletal anatomy and the detection of distinct micromorphological characters (i.e. shape of septal teeth, granulation of septocostae) Parascolymia bracherti has been identified as a new species in spite of the dissolved skeleton. In the recent era, Parascolymia like all Lobophylliidae is restricted to the Indo-Pacific region, where it is represented by a single species. The new species proves the genus also in the Miocene Mediterranean reef coral province. A review of the spatio-temporal relationships of fossil corals related to Parascolymia indicates that the genus was probably rooted in the Eastern Atlantic‒Western Tethys region during the Paleocene to Eocene and reached the Indo-Pacific region not before the Oligocene. The revealed palaeobiogeographical pattern shows an obvious congruence with that of Acropora and tridacnine bivalves reflecting a gradual equatorwards retreat of the marine biodiversity center parallel to the Cenozoic climate deterioration. PMID:26201071

  1. Hydrogeochemical investigations in a drained lake area: the case of Xynias basin (Central Greece).

    PubMed

    Charizopoulos, Nikos; Zagana, Eleni; Stamatis, Georgios

    2016-08-01

    In Xynias drained Lake Basin's area, central Greece, a hydrogeochemical research took place including groundwater sampling from 30 sampling sites, chemical analysis, and statistical analysis. Groundwaters present Ca-Mg-HCO3 as the dominant hydrochemical type, while their majority is mixed waters with non-dominant ion. They are classified as moderately hard to hard and are characterized by oxidizing conditions. They are undersaturated with respect to gypsum, anhydrite, fluorite, siderite, and magnesite and oversaturated in respect to calcite, aragonite, and dolomite. Nitrate concentration ranges from 4.4 to 107.4 mg/L, meanwhile 13.3 % of the samples exceed the European Community (E.C.) drinking water permissible limit. The trace elements Fe, Ni, Cr, and Cd present values of 30, 80, 57, and 50 %, respectively, above the maximum permissible limit set by E.C. Accordingly, the majority of the groundwaters are considered unsuitable for drinking water needs. Sodium adsorption ratio values (0.04-3.98) and the electrical conductivity (227-1200 μS/cm) classify groundwaters as suitable for irrigation uses, presenting low risk and medium soil alkalization risk. Factor analysis shows that geogenic processes associated with the former lacustrine environment and anthropogenic influences with the use of fertilizers are the major factors that characterized the chemical composition of the groundwaters. PMID:27450374

  2. Sources and pathways of polycyclic aromatic and saturated hydrocarbons in the Arkona Basin (Southern Baltic Sea, Central Europe)

    SciTech Connect

    Schulz, H.M.

    1996-12-31

    The Baltic Sea (Central Europe) is surrounded by coastal regions with long histories of industrialization. The heavy metal profiles in the sediments in the center of the Arkona Basin, one of the depressions of the southern Baltic Sea area, clearly reflect the historical anthropogenic influence. The Arkona Basin-is the final sink for materials derived from the Oder river which drains a highly polluted industrial area of Eastern Europe. Surficial muddy sediments from a close-meshed field of sampling-points were analyzed for distribution patterns of aliphatics and quantities and ratios of selected polycyclic aromatic hydrocarbons (PAH). These compounds are thought to reflect anthropogenic pollution related to emissions from traffic, heating, etc. We use these marker substances to test if the basin sediments reflect riverine input, and if additional sources can be identified.

  3. Cenozoic stratigraphic development in the north Chilean forearc: Implications for basin development and uplift history of the Central Andean margin

    NASA Astrophysics Data System (ADS)

    Hartley, Adrian J.; Evenstar, Laura

    2010-11-01

    Analysis of the Cenozoic stratigraphic development of the forearc of northern Chile between 18°S and 23°30'S, allows constraints to be placed on the timing and nature of basin formation and the uplift history of the Central Andes. Chronostratigraphic charts have been constructed from 20 lithostratigraphic sections distributed throughout the forearc. Sections were taken from the Longitudinal Valley, Central Depression, Calama Basin, Salar de Atacama, Precordillera and the western flank of the Western Cordillera. Correlation and timing of events is largely based on the presence of dated volcanic horizons in all the studied sections. Three chronostratigraphic units are defined based upon the presence of regional unconformities. Deposition of the Late Eocene to Early Miocene chronostratigraphic unit (38-19 Ma) commenced across an irregular unconformity surface between ˜ 38 and 30 Ma with alluvial fan and fluvial sediments derived from the east interbedded with rhyolitic ignimbrites. Aggradation after 25 Ma resulted in development of a large broad basin over much of northern Chile that expanded eastwards through onlap onto basement. Deposition terminated around 19 Ma with the development of an angular unconformity over much, but not all of the study area. During deposition of the Early to Late Miocene chronostratigraphic unit (18-10 Ma) emergent volcanic source areas to the east provided catchments for large fluvial systems that drained westwards into endorheic ephemeral lacustrine basins. Fold growth affected sedimentation restricting accommodation space to small intra-thrust basins in the Precordillera and localised disruption and unconformity development in the Longitudinal Valley. The Late Miocene to present day chronostratigraphic unit (10-0 Ma) followed the development of a regional angular unconformity at 10 Ma. Sedimentation was restricted to a series of thrust-bounded endorheic basins in both the Central Depression and the Precordillera sourced from the east

  4. An integrated framework to assess adaptation options to climate change impacts in an irrigated basin in Central North Chile

    NASA Astrophysics Data System (ADS)

    Vicuna, S.; Melo, O.; Meza, F. J.; Alvarez, P.; Maureira, F.; Sanchez, A.; Tapia, A.; Cortes, M.; Dale, L. L.

    2013-12-01

    Future climate conditions could potentially affect water supply and demand on water basins throughout the world but especially on snowmelt-driven agriculture oriented basins that can be found throughout central Chile. Increasing temperature and reducing precipitation will affect both the magnitude and timing of water supply this part of the world. Different adaptation strategies could be implemented to reduce the impacts of such scenarios. Some could be incorporated as planned policies decided at the basin or Water Use Organization levels. Examples include changing large scale irrigation infrastructure (reservoirs and main channels) either physically or its operation. Complementing these strategies it is reasonable to think that at a disaggregated level, farmers would also react (adapt) to these new conditions using a mix of options to either modify their patterns of consumption (irrigation efficiency, crop mix, crop area reduction), increase their ability to access new sources of water (groundwater, water markets) or finally compensate their expected losses (insurance). We present a modeling framework developed to represent these issues using as a case study the Limarí basin located in Central Chile. This basin is a renowned example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Farmers in this basin tackle climate variability by adopting different strategies that depend first on the reservoir water volume allocation rule, on the type and size of investment they have at their farms and finally their potential access to water markets and other water supplies options. The framework developed can be used to study these strategies under current and future climate scenarios. The cornerstone of the framework is an hydrology and water resources model developed on the WEAP platform. This model is able to reproduce the large scale hydrologic features of the basin such as

  5. Influence of the Amlia fracture zone on the evolution of the Aleutian Terrace forearc basin, central Aleutian subduction zone

    USGS Publications Warehouse

    Ryan, Holly F.; Draut, Amy E.; Keranen, Katie M.; Scholl, David W.

    2012-01-01

    During Pliocene to Quaternary time, the central Aleutian forearc basin evolved in response to a combination of tectonic and climatic factors. Initially, along-trench transport of sediment and accretion of a frontal prism created the accommodation space to allow forearc basin deposition. Transport of sufficient sediment to overtop the bathymetrically high Amlia fracture zone and reach the central Aleutian arc began with glaciation of continental Alaska in the Pliocene. As the obliquely subducting Amlia fracture zone swept along the central Aleutian arc, it further affected the structural evolution of the forearc basins. The subduction of the Amlia fracture zone resulted in basin inversion and loss of accommodation space east of the migrating fracture zone. Conversely, west of Amlia fracture zone, accommodation space increased arcward of a large outer-arc high that formed, in part, by a thickening of arc basement. This difference in deformation is interpreted to be the result of a variation in interplate coupling across the Amlia fracture zone that was facilitated by increasing subduction obliquity, a change in orientation of the subducting Amlia fracture zone, and late Quaternary intensification of glaciation. The change in coupling is manifested by a possible tear in the subducting slab along the Amlia fracture zone. Differences in coupling across the Amlia fracture zone have important implications for the location of maximum slip during future great earthquakes. In addition, shaking during a great earthquake could trigger large mass failures of the summit platform, as evidenced by the presence of thick mass transport deposits of primarily Quaternary age that are found in the forearc basin west of the Amlia fracture zone.

  6. Mountain-front recharge along the eastern side of the Middle Rio Grande Basin, central New Mexico

    USGS Publications Warehouse

    Anderholm, Scott K.

    2000-01-01

    Mountain-front recharge, which generally occurs along the margins of alluvial basins, can be a large part of total recharge to the aquifer system in such basins. Mountain-front recharge occurs as the result of infiltration of flow from streams that have headwaters in the mountainous areas adjacent to alluvial basins and ground- water flow from the aquifers in the mountainous areas to the aquifer in the alluvial basin. This report presents estimates of mountain-front recharge to the basin-fill aquifer along the eastern side of the Middle Rio Grande Basin in central New Mexico. The basin is a structural feature that contains a large thickness of basin-fill deposits, which compose the main aquifer in the basin. The basin is bounded along the eastern side by mountains composed of crystalline rocks of Precambrian age and sedimentary rocks of Paleozoic age. Precipitation is much larger in the mountains than in the basin; many stream channels debouch from the mountainous area to the basin. Chloride-balance and water-yield regression methods were used to estimate mountain-front recharge. The chloride-balance method was used to calculate a chloride balance in watersheds in the mountainous areas along the eastern side of the basin (subareas). The source of chloride to these watersheds is bulk precipitation (wet and dry deposition). Chloride leaves these watersheds as mountain-front recharge. The water-yield regression method was used to determine the streamflow from the mountainous watersheds at the mountain front. This streamflow was assumed to be equal to mountain-front recharge because most of this streamflow infiltrates and recharges the basin-fill aquifer. Total mountain-front recharge along the eastern side of the Middle Rio Grande Basin was estimated to be about 11,000 acre- feet per year using the chloride-balance method and about 36,000 and 38,000 acre-feet per year using two water-yield regression equations. There was a large range in the recharge estimates in a

  7. Managing drought risk with a computer model of the Raritan River Basin water-supply system in central New Jersey

    USGS Publications Warehouse

    Dunne, Paul; Tasker, Gary

    1996-01-01

    The reservoirs and pumping stations that comprise the Raritan River Basin water-supply system and its interconnections to the Delaware-Raritan Canal water-supply system, operated by the New Jersey Water Supply Authority (NJWSA), provide potable water to central New Jersey communities. The water reserve of this combined system can easily be depleted by an extended period of below-normal precipitation. Efficient operation of the combined system is vital to meeting the water-supply needs of central New Jersey. In an effort to improve the efficiency of the system operation, the U.S. Geological Survey (USGS), in cooperation with the NJWSA, has developed a computer model that provides a technical basis for evaluating the effects of alternative patterns of operation of the Raritan River Basin water-supply system. This fact sheet describes the model, its technical basis, and its operation.

  8. Fate of copper complexes in hydrothermally altered deep-sea sediments from the Central Indian Ocean Basin.

    PubMed

    Chakraborty, Parthasarathi; Sander, Sylvia G; Jayachandran, Saranya; Nath, B Nagender; Nagaraju, G; Chennuri, Kartheek; Vudamala, Krushna; Lathika, N; Mascarenhas-Pereira, Maria Brenda L

    2014-11-01

    The current study aims to understand the speciation and fate of Cu complexes in hydrothermally altered sediments from the Central Indian Ocean Basin and assess the probable impacts of deep-sea mining on speciation of Cu complexes and assess the Cu flux from this sediment to the water column in this area. This study suggests that most of the Cu was strongly associated with different binding sites in Fe-oxide phases of the hydrothermally altered sediments with stabilities higher than that of Cu-EDTA complexes. The speciation of Cu indicates that hydrothermally influenced deep-sea sediments from Central Indian Ocean Basin may not significantly contribute to the global Cu flux. However, increasing lability of Cu-sediment complexes with increasing depth of sediment may increase bioavailability and Cu flux to the global ocean during deep-sea mining. PMID:25108489

  9. Synchronous late Pleistocene extensional faulting and basaltic volcanism in pluvial Fort Rock basin, central Oregon

    NASA Astrophysics Data System (ADS)

    Mackey, B. H.; Castonguay, S. R.; Wallace, P. J.; Weldon, R. J.

    2012-12-01

    Central Oregon, where northern Basin and Range extension intersects the High Lava Plains, exhibits widespread extensional faulting and Quaternary basaltic volcanism, yet the relations between the processes are complex and chronology is poorly constrained. Here we use cosmogenic 3He exposure dating of basalt to quantify the timing of normal faulting and emplacement of a related cinder cone volcanic field on the margins of pluvial Fort Rock Lake. The N15W striking North Christmas Valley fault system offsets High Lava Plains volcanics forming a ~3 km wide graben that transects the eastern Fort Rock Basin. Several young volcanic vents, including the ~740 ka Green Mountain (GM) shield volcano, and younger Four Craters lava field (4C), are aligned parallel with, and bounded by the graben. The western edge of the graben is expressed as an enigmatic monocline with up to10 m vertical throw and a prominent vertical hinge crack due to folding of the overlying GM lava flows. Younger basalt flows of the 4C field abut and flow into this crack, known as the 'Crack in the Ground' fault. Exposure dating of the 4C lava field on the eastern flank of GM indicates an emplacement age of 13 ka, which is largely consistent across multiple flows emerging from the 4 linearly aligned cinder cones. In addition, we dated the GM basalt exposed in the sub-vertical walls of the crack (the fault wall), which are cleanly separated by up to 10 m, but with uneroded (and in places identically matching) crack walls. Samples were taken >3 m below ground surface to avoid pre-faulting inheritance, and required considerable shielding corrections, but return a consistent exposure age of ~13 ka. This suggests substantial crack opening occurred at the same time the 4C lava was emplaced. A small fault offsets the 4C lava where it flows across the Crack, and dating the fault wall of this younger lava also generated an exposure age of 13 ka, indicating it must have ruptured shortly after the 4C lava cooled

  10. Tectono-sedimentary evolution of the Tertiary Piedmont Basin (NW Italy) within the Oligo-Miocene central Mediterranean geodynamics

    NASA Astrophysics Data System (ADS)

    Maino, Matteo; Decarlis, Alessandro; Felletti, Fabrizio; Seno, Silvio

    2013-06-01

    analyze the tectono-sedimentary and thermochronometric constraints of the Tertiary Piedmont Basin (TPB) and its adjoining orogen, the Ligurian Alps, providing new insights on the basin evolution in response to a changing geodynamic setting. The geometry of the post-metamorphic faults of the Ligurian belt as well as the fault network that controlled the Oligo-Miocene TPB deposition has been characterized through a detailed structural analysis. Three main faulting stages have been distinguished and dated thanks to the relationships among faults and basin stratigraphy and thermochronometric data. The first stage (F1, Rupelian-Early Chattian) is related to the development of extensional NNW-directed faults, which controlled the exhumation of the orogen and the deposition of nearshore clastics. During the Late Chattian, the basin drowning is marked by mudstones and turbidites, which deposition was influenced by the second faulting stage (F2). This phase was mainly characterized by NE- to ENE-striking faults developed within a transtensional zone. Since the Miocene, the whole area was dominated by transpressive tectonics. The sedimentation was represented by a condensed succession followed by a very thick, turbiditic complex. At the regional scale, this succession of events reflects the major geodynamic reorganization in the central Mediterranean region during the Oligo-Miocene times, induced by the late-collisional processes of the Alps, by the eastward migration of the Apennines subduction and by the opening of extensional basins (i. e., the Liguro-Provençal Ocean).

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

    SciTech Connect

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

    1991-12-01

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

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

    SciTech Connect

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

    1991-12-01

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

  13. 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

  14. Statistical prediction of seasonal discharge in the Naryn basin for water resources planning in Central Asia

    NASA Astrophysics Data System (ADS)

    Apel, Heiko; Gafurov, Abror; Gerlitz, Lars; Unger-Shayesteh, Katy; Vorogushyn, Sergiy; Merkushkin, Aleksandr; Merz, Bruno

    2016-04-01

    The semi-arid regions of Central Asia crucially depend on the water resources supplied by the mountainous areas of the Tien-Shan and Pamirs. During the summer months the snow and glacier melt water of the rivers originating in the mountains provides the only water resource available for agricultural production but also for water collection in reservoirs for energy production in winter months. Thus a reliable seasonal forecast of the water resources is crucial for a sustainable management and planning of water resources.. In fact, seasonal forecasts are mandatory tasks of national hydro-meteorological services in the region. Thus this study aims at a statistical forecast of the seasonal water availability, whereas the focus is put on the usage of freely available data in order to facilitate an operational use without data access limitations. The study takes the Naryn basin as a test case, at which outlet the Toktogul reservoir stores the discharge of the Naryn River. As most of the water originates form snow and glacier melt, a statistical forecast model should use data sets that can serve as proxy data for the snow masses and snow water equivalent in late spring, which essentially determines the bulk of the seasonal discharge. CRU climate data describing the precipitation and temperature in the basin during winter and spring was used as base information, which was complemented by MODIS snow cover data processed through ModSnow tool, discharge during the spring and also GRACE gravimetry anomalies. For the construction of linear forecast models monthly as well as multi-monthly means over the period January to April were used to predict the seasonal mean discharge of May-September at the station Uchterek. An automatic model selection was performed in multiple steps, whereas the best models were selected according to several performance measures and their robustness in a leave-one-out cross validation. It could be shown that the seasonal discharge can be predicted with

  15. The Influence of the Wallula Fault and Pasco Basin on the Tectonic Framework of South-Central Washington

    NASA Astrophysics Data System (ADS)

    Blakely, R. J.; Sherrod, B. L.; Wells, R. E.; Weaver, C. S.

    2011-12-01

    The Yakima fold and thrust belt (YFTB) in eastern Washington manifests broad-scale regional deformation of the Cascadia backarc occurring prior, during, and after emplacement of Miocene flood basalts of the Columbia River Basalt Group (CRBG). CRBG basalts are strongly magnetic, and anticlines and faults of the YFTB are well displayed in high-resolution aeromagnetic surveys. Gravity anomalies, on the other hand, reflect in part the thickness of pre-Miocene sedimentary rocks beneath CRBG. The broad width of the YFTB in central Washington narrows eastward toward Idaho, with anticlines and faults merging into the narrow Wallula fault zone (WFZ). The WFZ is one element of the Olympic-Wallowa lineament (OWL), an alignment of topographic and structural elements extending from the Olympic Peninsula in Washington to the Wallowa Mountains in Oregon. The tectonic relevance of the OWL, particularly the degree to which dextral shear has contributed to its evolution, is still a matter of discussion. The Pasco basin, a late Cenozoic sedimentary basin atop CRBG, is associated with a broad gravity low. The thickness of post-CRBG sediments is insufficient to account for the entire gravity anomaly, suggesting the presence of a sediment-filled basin beneath CRBG. YFTB evolution and Quaternary deformation appear to have been influenced by the Pasco basin, as evidenced by potential-field anomalies. Northernmost faults of the YFTB (Frenchman Hills, Saddle Mountains, and Umtanum Ridge) abruptly terminate as they cross the western margin of the basin. Derivative maps (e.g., maximum horizontal gradient and tilt derivative) calculated from high-resolution magnetic anomalies show no evidence of these faults beyond their mapped extent in this area. Southern faults of the YFTB (Rattlesnake Mountain, Horse Heaven Hills, and Columbia Hills) in central Washington are on strike with the Pasco basin but veer abruptly southeastward at its southwestern margin to merge into the WFZ. Northwest

  16. Two-stage formation model of the Junggar basin basement: Constraints to the growth style of Central Asian Orogenic Belt

    NASA Astrophysics Data System (ADS)

    He, Dengfa

    2016-04-01

    Junggar Basin is located in the central part of the Central Asian Orogenic Belt (CAOB). Its basement nature is a highly controversial scientific topic, involving the basic style and processes of crustal growth. Some researchers considered the basement of the Junggar Basin as a Precambrian continental crust, which is not consistent with the petrological compositions of the adjacent orogenic belts and the crust isotopic compositions revealed by the volcanic rocks in the basin. Others, on the contrary, proposed an oceanic crust basement model that does not match with the crustal thickness and geophysical characteristics of the Junggar area. Additionally, there are several viewponits, such as the duplex basement with the underlying Precambrian crystalline rocks and the overlying pre-Carboniferous folded basement, and the collaged basement by the Precambrian micro-continent block in the central part and the Hercynian accretionary folded belts circling it. Anyway, it is necessary to explain the property of basement rock, its strong inhomogeneous compositions as well as the geophysical features. In this paper, based on the borehole data from more than 300 industry wells drilled into the Carboniferous System, together with the high-resolution gravity and magnetic data (in a scale of 1:50,000), we made a detailed analysis of the basement structure, formation timing and processes and its later evolution on a basis of core geochemical and isotopic analysis. Firstly, we defined the Mahu Pre-Cambrian micro-continental block in the juvenile crust of Junggar Basin according to the Hf isotopic analysis of the Carboniferous volcanic rocks. Secondly, the results of the tectonic setting and basin analysis suggest that the Junggar area incorporates three approximately E-W trending island arc belts (from north to south: Yemaquan- Wulungu-Chingiz, Jiangjunmiao-Luliang-Darbut and Zhongguai-Mosuowan- Baijiahai-Qitai island arcs respectively) and intervened three approximately E-W trending

  17. Fungi in deep-sea sediments of the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Damare, Samir; Raghukumar, Chandralata; Raghukumar, S.

    2006-01-01

    Although a great amount of information is available on bacteria inhabiting deep-sea sediments, the occurrence of fungi in this environment has been poorly studied and documented. We report here the occurrence of fungi in deep-sea sediments from ˜5000 m depth in the Central Indian Basin (9-16°S and 73-76°E). A total of 181 cultures of fungi, most of which belong to terrestrial sporulating species, were isolated by a variety of isolation techniques. Species of Aspergillus and non-sporulating fungi were the most common. Several yeasts were also isolated. Maximum species diversity was observed in 0-2 cm sections of the sediment cores. Direct staining of the sediments with Calcofluor, a fluorescent optical brightener, revealed the presence of fungal hyphae in the sediments. Immunofluorescence using polyclonal antibodies raised against a deep-sea isolate of Aspergillus terreus (# A 4634) confirmed its presence in the form of hyphae in the sub-section from which it was isolated. A total of 25 representative species of fungi produced substantial biomass at 200 bar pressure at 30° as well as at 5 °C. Many fungi showed abnormal morphology at 200 bar/5 °C. A comparison of terrestrial isolates with several deep-sea isolates indicated that the former could grow at 200 bar pressure when growth was initiated with mycelial inocula. However, spores of a deep-sea isolate A. terreus (# A 4634), but not the terrestrial ones, showed germination at 200 bar pressure and 30 °C. Our results suggest that terrestrial species of fungi transported to the deep sea are initially stressed but may gradually adapt themselves for growth under these conditions.

  18. Petrography and palynology of quartzites in the Sirte Basin, central Libya

    NASA Astrophysics Data System (ADS)

    Tawadros, E.; Rasul, S. M.; Elzaroug, R.

    2001-04-01

    Petrographic and palynological analysis and wireline log correlations of the so-called pre-Upper Cretaceous 'quartzites' in the central Sirte Basin permits, for the first time, the recognition of the development of six types of quartzites and sandstones of Late Cambrian, Late Devonian, Devonian-Carboniferous and Early Cretaceous age. The Late Cambrian section age, dated by the presence of associated marine acritarchs Vulcanisphaera turbata and Retisphaeridium dichamerum, comprises two shallow marine quartzite units separated by a varicoloured argillaceous feldspathic sandstone unit (Red Beds). The two quartzite units show tidal bedding and mud couplets. They were probably deposited in a subtidal environment. They form fractured reservoirs in the giant Attahaddy Gas Field. The varicoloured sandstone unit (Red Beds) is rich in Skolithos and was probably deposited in an intertidal environment. A Late Devonian (Strunian) shallow marine to continental sandstone unit age dated by the marine acritarch Gorgonisphaeridium solidum and the land-derived spore Verruciretusispora cf. famenensis has been identified in wells V1-59 in the southwest of the study area and EE1-59 in the southeast. A Carboniferous (Visean) sandstone unit age dated by the land-derived spores Aratrisporites saharaensis and Calamospora sp. has been identified in wells C3-6, KKKK1-6, BBBB2-6 and V1-59. The Early Cretaceous continental fractured quartzite unit dated by tricolpate pollen produces oil in the Wadi Field. The study reveals that the Devonian and Carboniferous sandstones, with good primary porosity, previously considered Nubian and Cambro-Ordovician, respectively, form an attractive hydrocarbon-bearing trend in the southern part of the study area.

  19. Hydrothermal signature in ferromanganese oxide coatings on pumice from the Central Indian Ocean Basin

    NASA Astrophysics Data System (ADS)

    Kalangutkar, Niyati G.; Iyer, Sridhar D.; Mascarenhas-Pereira, Maria B. L.; Nath, B. Nagender

    2015-06-01

    Mineralogical and elemental analyses of 20 ferromanganese (FeMn)-coated pumice samples from the Central Indian Ocean Basin (CIOB) indicate that todorokite is the major mineral phase, whereas vernadite occurs only rarely. Based on major, trace and rare earth elements (REEs) as well as Ce anomalies, the sources of the FeMn oxides were identified to be either hydrogenous, hydrothermal-plume fallout, diagenetic or a combination of these. Plots of Fe/Mn vs. Ce or Co reveal a distinct demarcation of the diagenetic, hydrogenous and plume fallout samples. Five samples are interpreted to be of hydrothermal origin because these show negative Ce anomalies and low Co/Zn ratios (0.5 to 1.1), and are masked by diagenesis. The relative contributions of hydrogenous, hydrothermal and diagenetic inputs were assessed in terms of ternary mixing patterns using REE mass balance equations. Furthermore, the hypothetical Ce anomaly (Ce/Ce*) was calculated using ternary mixing calculations for hydrogenous, hydrothermal and diagenetic end-members to ascertain the input to FeMn oxides on the pumice samples. This revealed a distinction between hydrogenous and hydrothermal components but diagenetic and plume fallout components could not be distinguished because this scheme comprises a three end-member calculation. A conservative estimate indicates the hydrothermal component to vary between 24% and 72%. The growth rates of the oxides, as estimated from published empirical methods, range between 3 and 47 mm/106 years. Fe/Mn ratios yielded a maximum age of 5-7 Ma and a minimum of 0.04-0.1 Ma. This suggests that the commencement of accretion of the FeMn oxides generally precedes the age of the Krakatau 1883 eruption, which is commonly considered as being the prime source of pumice to the CIOB. This is the first evidence of hydrothermal influence in the formation of FeMn oxides on CIOB pumice.

  20. Monoterpene Compositions of Three Forested Ecosystems in the Central Amazon Basin

    NASA Astrophysics Data System (ADS)

    Jardine, A.; Fuentes, J. D.; Manzi, A. O.; Higuchi, N.; Chambers, J. Q.; Jardine, K.

    2014-12-01

    Monoterpenes play fundamental roles as secondary metabolites in forested ecosystems and as gas and liquid phase secondary organic aerosol (SOA) precursors in their surrounding atmospheres. While the chemical pathways involved in ozonolysis driven SOA formation from individual monoterpene precursors is known, local and regional chemical transport models are still lacking observations of speciated monoterpenes from forested atmospheres. Here, we present high vertically resolved mixing ratio profiles of speciated monoterpenes from the ambient air of three neighboring forested ecosystems in the central Amazon Basin. Two well-drained plateau primary forests and one seasonally flooded valley forest were sampled during the afternoon hours (13:00 - 16:30) on walkup towers from the initiation of the 2013-14 wet season through the onset of the 2014 dry season (Nov 2013 - Jul 2014). Ambient mixing ratios in all three ecosystems were greatest in the upper canopy with secondary sources of some monoterpenes within the sub-canopies. Relative vertical compositions of monoterpenes did not change significantly throughout the seasons for either ecosystem type. Both ecosystem types were dominated by d-limonene (up to 1.6 ppb) with equally strong mixing ratios of alpha-pinene in the valley compared to the much weaker a-pinene mixing ratios on the plateaus (up to 200 ppt). The highly reactive cis- and trans-beta-ocimene were consistently present in both ecosystems (up to 250 ppt) with the addition of equally high camphene mixing ratios in the valley forest (up to 200 ppt) which is present in the plateau ecosystems in low quantities (50 ppt). With respect to clean atmosphere mixing ratios of 10 ppb ozone, lifetimes are below 2 hours for camphene and below 30 minutes for ocimene, suggesting a potentially large impact on local and possibly regional ozonolysis and subsequent SOA composition.

  1. Multiple ash layers in late Quaternary sediments from the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Mascarenhas-Pereira, M. B. L.; Nagender Nath, B.; Iyer, S. D.; Borole, D. V.; Parthiban, G.; Jijin, R.; Khedekar, V.

    2016-04-01

    We have investigated three sediment cores collected from water depths > 5000 m along the transect 76°30‧E in close proximity to a fracture zone in the Central Indian Basin (CIB). The cores yielded five volcanic horizons of which four have visual and dispersed shards. Rhyolitic glass shards of bubble wall, platy, angular and blocky types were retrieved from various stratigraphic horizons in the cores. The abundance of glass shards, composition of bulk sediments, and 230Thexcess ages of the host sediments were used to distinguish the volcanic horizons. Of the four volcanic horizons, three are now newly reported and correspond to ages of ~ 85, 107-109 and 142-146 ka while the fourth horizon is of 70-75 ka. By using trace element ratios and Cr and Nb-based normative calculations, cryptotephra has been identified for the first time from the CIB sediment. The cryptotephra forms the fifth ash horizon and is of ~ 34 ka. A comparison with the published data on volcanic tephra in and around the Indian Ocean indicate the shard rich horizon (SRH) of 70-75 ka to resemble the Younger Toba Tuffs (YTT), while the other volcanic horizons that were deposited during different time periods do not correlate with any known marine or terrestrial records. These tephra layers have produced a tephrostratigraphic framework across the tectonically and volcanically complex regions of the CIB. Due to the lack of terrestrial equivalents of these tephra, it is hypothesized that the newly found volcanic horizons may have been derived from submarine volcanic eruptions. Multiple layers of submarine volcaniclastic deposits found at water depths as great as 5300 m reaffirm the growing belief that submarine phreatomagmatic eruptions are much more common in the intraplate region of the Indian Ocean than previously reported.

  2. Preliminary paleomagnetic results from Miocene Monterey Formation, Shell Beach, Pismo Basin, central California

    SciTech Connect

    Khan, S.M.; Coe, R.S.; Barron, J.A.

    1988-03-01

    An excellently exposed 300-m thick section of the Monterey Formation at Shell Beach, Pismo basin, has been sampled at intervals of 2-5 m for paleomagnetic analysis. This study is part of an ongoing research aimed at providing detailed magnetostratigraphy and geochronology of the Monterey Formation sections from northern and central California. Here they report on the detailed magnetostratigraphy and diatom biostratigraphy of the upper 150 m of the Shell Beach section, which spans a 2-m.y. long interval in the upper middle Miocene (upper lower Mohnian). Their preliminary data reveal two distinct components of magnetization in about 75% of the dolomite samples and 40-60% of the samples from calcareous to siliceous shales and cherty porcelanitic rocks. The first of these components (a), which is removed at T less than or equal to 200/sup 0/C, is presumably recent viscous magnetization. The thermally discrete second component (b) had dual polarity and stable and consistent directions with a relatively narrow unblocking temperature range (200/sup 0/-400/sup 0/C). Usually this component remains blocked on heating to 450/sup 0/-500/sup 0/C and is then masked by unusually high intensity components of magnetochemical origin produced during heating in the lab. In their best samples, orthogonal vector diagrams show that b is the early characteristic remanence, and all evidence to date suggests that this component is pre-Pliocene-Pleistocene folding and most likely primary. By using diatom data extracted from their samples, they are attempting to obtain detailed magnetostratigraphy for this section of the Monterey Formation.

  3. Earthquake source parameters and scaling relationships in Hungary (central Pannonian basin)

    NASA Astrophysics Data System (ADS)

    Süle, Bálint; Wéber, Zoltán

    2013-04-01

    Fifty earthquakes that occurred in Hungary (central part of the Pannonian basin) with local magnitude M_{L} ranging from 0.8 to 4.5 have been analyzed. The digital seismograms used in this study were recorded by six permanent broadband stations and 20 short-period ones at hypocentral distances between 10 and 327 km. The displacement spectra for P- and SH-waves were analyzed according to Brune's source model. Observed spectra were corrected for path-dependent attenuation effects using an independent regional estimate of the quality factor Q S . To correct spectra for near-surface attenuation, the κ parameter was calculated, obtaining it from waveforms recorded at short epicentral distances. The values of the κ parameter vary between 0.01 and 0.06 s with a mean of 0.03 s for P-waves and between 0.01 and 0.09 s with a mean of 0.04 s for SH-waves. After correction for attenuation effects, spectral parameters (corner frequency and low-frequency spectral level) were estimated by a grid search algorithm. The obtained seismic moments range from 4.21×1011 to 3.41×1015 Nm (1.7 ≤ M w ≤ 4.3). The source radii are between 125 and 1,343 m. Stress drop values vary between 0.14 and 32.4 bars with a logarithmic mean of 2.59 bars (1 bar = 105 Pa). From the results, a linear relationship between local and moment magnitudes has been established. The obtained scaling relations show slight evidence of self-similarity violation. However, due to the high scatter of our data, the existence of self-similarity cannot be excluded.

  4. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico)

    NASA Astrophysics Data System (ADS)

    Lenhardt, Nils; Götz, Annette E.

    2015-04-01

    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  5. Long-term agroecosystem research in the central Mississippi river basin: introduction, establishment, and overview.

    PubMed

    Sadler, E John; Lerch, Robert N; Kitchen, Newell R; Anderson, Stephen H; Baffaut, Claire; Sudduth, Kenneth A; Prato, Anthony A; Kremer, Robert J; Vories, Earl D; Myers, D Brent; Broz, Robert; Miles, Randall J; Young, Fred J

    2015-01-01

    Many challenges currently facing agriculture require long-term data on landscape-scale hydrologic responses to weather, such as from the Goodwater Creek Experimental Watershed (GCEW), located in northeastern Missouri, USA. This watershed is prone to surface runoff despite shallow slopes, as a result of a significant smectitic clay layer 30 to 50 cm deep that restricts downward flow of water and gives rise to a periodic perched water table. This paper is the first in a series that documents the database developed from GCEW. The objectives of this paper are to (i) establish the context of long-term data and the federal infrastructure that provides it, (ii) describe the GCEW/ Central Mississippi River Basin (CMRB) establishment and the geophysical and anthropogenic context, (iii) summarize in brief the collected research results published using data from within GCEW, (iv) describe the series of papers this work introduces, and (v) identify knowledge gaps and research needs. The rationale for the collection derives from converging trends in data from long-term research, integration of multiple disciplines, and increasing public awareness of increasingly larger problems. The outcome of those trends includes being selected as the CMRB site in the USDA-ARS Long-Term Agro-Ecosystem Research (LTAR) network. Research needs include quantifying watershed scale fluxes of N, P, K, sediment, and energy, accounting for fluxes involving forest, livestock, and anthropogenic sources, scaling from near-term point-scale results to increasingly long and broad scales, and considering whole-system interactions. This special section informs the scientific community about this database and provides support for its future use in research to solve natural resource problems important to US agricultural, environmental, and science policy. PMID:25602315

  6. Stratigraphic and tectonic studies in the central Aquitaine Basin, northern Pyrenees: Constraints on the subsidence and deformation history of a retro-foreland basin

    NASA Astrophysics Data System (ADS)

    Rougier, Géraldine; Ford, Mary; Christophoul, Frédéric; Bader, Anne-Gaëlle

    2016-03-01

    The central North-Pyrenean retrowedge developed on a thinned lithosphere, rich in Keuper evaporites. The behavior of this retro-foreland system is studied using subsidence analyses and a sequentially restored cross-section (120 km, Saint-Gaudens to Castelsarrasin) constrained by new chrono- and lithostratigraphy, surface and subsurface data. During the Late Cretaceous, a first episode of foreland subsidence (E1) produced a narrow marine depocenter (Comminges Basin, 30 km wide), supplied from the east. A synchronous early deformation involved inversion of basement faults and gentle shortening (4.5 km) of the Mesozoic strata above a Keuper decoupling layer. A tectonically quiet period (Q, Paleocene), characterized by a condensed succession (marine and continental), was followed by a second episode of subsidence (E2), basin migration and gentle thick- and thin-skinned shortening (8 km). Continental sedimentation, supplied by the uplifting orogen, first filled a narrow flexural basin (E2, M-L Eocene), then expanded across the Aquitaine Platform (E3, Oligocene-Miocene).

  7. Shear velocity structure beneath the central United States: implications for the origin of the Illinois Basin and intraplate seismicity

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Gilbert, Hersh; Andronicos, Christopher; Hamburger, Michael W.; Larson, Timothy; Marshak, Stephen; Pavlis, Gary L.; Yang, Xiaotao

    2016-03-01

    We present new estimates of lithospheric shear velocities for the intraplate seismic zones and the Illinois Basin in the U.S. midcontinent by analyzing teleseismic Rayleigh waves. We find that relatively high crustal shear velocities (VS) characterize the southern Illinois Basin, while relatively low crustal velocities characterize the middle and lower crust of the central and northern Illinois Basin. The observed high crustal velocities may correspond to high-density mafic intrusions emplaced into the crust during the development of the Reelfoot Rift, which may have contributed to the subsidence of the Illinois Basin. The low crustal VS beneath the central and northern basin follow the La Salle deformation belt. We also observe relatively low velocities in the mantle beneath the New Madrid seismic zone where VS decreases by about 7% compared to those outside of the rift. The low VS in the upper mantle also extends beneath the Wabash Valley and Ste. Genevieve seismic zones. Testing expected VS reductions based on plausible thermal heterogeneities for the midcontinent indicates that the 7% velocity reduction would not result from elevated temperatures alone. Instead this scale of anomaly requires a contribution from some combination of increased iron and water content. Both rifting and interaction with a mantle plume could introduce these compositional heterogeneities. Similar orientations for the NE-SW low-velocity zone and the Reelfoot Rift suggest a rift origin to the reduced velocities. The low VS upper mantle represents a weak region and the intraplate seismic zones would correspond to concentrated crustal deformation above weak mantle.

  8. Conodont and fusulinid biostratigraphy and history of the Pennsylvanian to Lower Permian Keeler Basin, east-central California

    USGS Publications Warehouse

    Stevens, C.H.; Stone, P.; Ritter, S.M.

    2001-01-01

    The Pennsylvanian-Lower Permian Keeler Canyon Formation and lower part of the Lower Permian Lone Pine Formation in east-central California were deposited in a deep-water basin that originated in the Morrowan (Early Pennsylvanian), was fully established by the Desmoinesian (Middle Pennsylvanian), and lasted into the Sakmarian (Early Permian). Stratigraphic studies indicate that the Keeler Canyon Formation can be divided into members recognizable throughout the area of our detailed mapping. From older to younger they are the Tinemaha Reservoir, Tihvipah Limestone, Cerro Gordo Spring, and Salt Tram Members. Rocks in this basin, here referred to as the Keeler basin, contain numerous fusulinid and conodont faunas most of which were deposited by sediment-gravity flows probably originating at the margin of the Bird Spring carbonate platform to the northeast. Sixty-one species of Atokan to Sakmarian fusulinids and 38 species of Desmoinesian to Sakmarian conodonts are recognized. These, in addition to four species of Morrowan conodonts previously reported, show that every stage from the Morrowan to Sakmarian is represented in the basin. The fusulinid faunas are composed largely of taxa of the North American craton, especially the south-central USA, with important endemic constituents and some McCloud Limestone forms, representing the Eastern Klamath terrane. Conodonts are closely similar to species in the Ural Mountains region of Russia and Kazakhstan, as well as the American midcontinent. The co-occurrence of fusulinids and conodonts in the Keeler basin results in a better correlation of zones based on these two groups of fossils than generally is possible.

  9. Shelf-to-basin resedimented carbonates of the southern margin of the Jurassic central high Atlas trough, Morocco

    SciTech Connect

    Hazlett, B.H.; Warme, J.E.

    1988-08-01

    The Central High Atlas Mountains occupy the site of an Early to Middle Jurassic east-west-trending seaway known as the Central High Atlas trough. Late Triassic-Early Jurassic continental rifting, combined with a transtensional structural regime, formed a system of pull-apart basins comprising the trough. A thick sequence of carbonate shelf-to-basin-plain deposits filled the trough and were later uplifted and exposed during the Oligocene Alpine orogeny. Stratigraphic analysis of 50 km/sup 2/ located along the trough's southern shelf margin reveals a 1,200 m-thick wedge of slope and basin-plain deposits. These deposits are divided into four lithostratigraphic units: (1) pelagic mudstones, (2) channel deposits composed of grainstones and packstones interbedded with marls and mudstones, (3) turbidite deposits composed of grainstones, packstones, and wackestones cyclically interbedded with marls and mudstones, and (4) cyclically interbedded marls and mudstones. This laterally continuous thick wedge of resedimented deposits suggests that a line source of platform-margin sediments fed coalescing base-of-slope aprons. These aprons probably accumulated in an actively subsiding half-graben parallel to the shelf margin. While tectonics played the major role in basin evolution, sea level fluctuations and climate influenced the influx of carbonate and terrigenous sediments. Rapid cessation of mid-Sinemurian shallow-water platform deposition and regionally transgressive Domerian-Toarcian marls indicate eustatic sea level rises affected basin sedimentation. Periodic climate changes, perhaps related to the Milankovitch effect, may have led to systematic variations in carbonate sediment supply, resulting in cyclic sedimentation.

  10. HYDROGEOMORPHIC SETTING, CHARACTERISTICS, AND RESPONSE TO STREAM INCISION OF MONTANA RIPARIAN MEADOWS IN THE CENTRAL GREAT BASIN--IMPLICATIONS FOR RESTORATION

    EPA Science Inventory

    Riparian wet meadow complexes in the mountains of the central Great Basin are scarce, ecologically important systems that are threatened by stream incision. An interdisciplinary group has investigated 1) the origin, characteristics, and controls on the evolution of these riparian...

  11. THE HYDROLOGIC SYSTEM: GEOMORPHIC AND HYDROGEOLOGIC CONTROLS ON SURFACE AND SUBSURFACE FLOW REGIMES IN RIPARIAN MEADOW ECOSYSTEMS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    Riparian corridors in upland watersheds in the Great Basin of central Nevada contain the majority of the region's biodiversity. Water, in both surface and subsurface flow regimes, is an important resource sustaining these sensitive ecosystems and other similar riparian ecosystem...

  12. Quaternary landscape evolution of tectonically active intermontane basins: the case of the Middle Aterno River Valley (Abruzzo, Central Italy)

    NASA Astrophysics Data System (ADS)

    Falcucci, Emanuela; Gori, Stefano; Della Seta, Marta; Fubelli, Giandomenico; Fredi, Paola

    2014-05-01

    The Middle Aterno River Valley is characterised by different Quaternary tectonic depressions localised along the present course of the Aterno River (Central Apennine) .This valley includes the L'Aquila and Paganica-Castelnuovo-San Demetrio tectonic basins, to the North, the Middle Aterno Valley and the Subequana tectonic basin, to the South. The aim of this contribution is to improve the knowledge about the Quaternary geomorphological and tectonic evolution of this portion of the Apennine chain. A synchronous lacustrine depositional phase is recognized in all these basins and attributed to the Early Pleistocene by Falcucci et al. (2012). At that time, this sector of the chain showed four distinct closed basins, hydrologically separated from each other and from the Sulmona depression. This depression, actually a tectonic basin too, was localized South of the Middle Aterno River Valley and it was drained by an endorheic hydrographic network. The formation of these basins was due to the activity of different fault systems, namely the Upper Aterno River Valley-Paganica system and San Pio delle Camere fault, to the North, and the Middle Aterno River Valley-Subequana Valley fault system to the South. These tectonic structures were responsible for the origin of local depocentres inside the depressions which hosted the lacustrine basins. Ongoing surveys in the uppermost sectors of the Middle Aterno River Valley revealed the presence of sub-horizontal erosional surfaces that are carved onto the carbonate bedrock and suspended several hundreds of metres over the present thalweg. Gently dipping slope breccias referred to the Early Pleistocene rest on these surfaces, thus suggesting the presence of an ancient low-gradient landscape adjusting to the local base level.. Subsequently, this ancient low relief landscape underwent a strong erosional phase during the Middle Pleistocene. This erosional phase is testified by the occurrence of valley entrenchment and of coeval fluvial

  13. 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.

  14. 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.

  15. Tectonic evolution and paleogeography of the Mesozoic Pucará Basin, central Peru

    NASA Astrophysics Data System (ADS)

    Rosas, Silvia; Fontboté, Lluís; Tankard, Anthony

    2007-06-01

    The Pucará Basin of Peru is an elongate trough that subsided landward of a NNW-trending structural high during the Late Triassic-Early Jurassic. It formed as a postrift regional sag as the earlier Triassic fault-controlled Mitu rifts yoked together. The rift and transitional postrift basins were associated with a NW-striking sinistral shear zone that controlled isopachs and facies distributions and resulted in magmatism and mineralization along its trend. A distinct association of later dolomitization and MVT lead-zinc mineralization also occurs with these basin-forming shear zones. Although basaltic and andesitic extrusives are common, there is no evidence that the Pacific margin was a magmatic arc until the upper Pucará, and then only weakly developed in northern Peru. Except in the upper Pucará of northwest Peru, geochemical studies, including whole rock and trace element analyses, indicate that intercalations of volcanic material have intraplate rift affinities. The basin fill has a three-part stratigraphic subdivision, comprising lower and upper carbonate platforms with an intermediate phase of basin overdeepening and sediment starvation that resulted in a regional, organic-rich argillaceous drape. Stratigraphic accumulation was dominated by axial patterns of onlap and progradation, though facies characteristics show it was augmented by periodic flooding of the western basin margin high. Marine invertebrate fossils indicate normal marine salinities. The sedimentological interpretation is based on a SW-NE transect in the southern part of the Pucará Basin. The Chambará (Norian-Rhaetian) and Condorsinga (Toarcian) formations were constructed principally by shallow-water carbonate sedimentation in lagoon-like subtidal, intertidal, and supratidal paleoenvironments. The subtidal carbonate platform is dominated by oolitic grainstones with subordinate bioclastic packstones. Subordinate open-basin facies in the Chambará Formation consist principally of crinoidal

  16. Tectonic Evolution of the Central Andes during Mesozoic-Cenozoic times: Insights from the Salar de Atacama Basin

    NASA Astrophysics Data System (ADS)

    Peña Gomez, M. A.; Bascunan, S. A.; Becerra, J.; Rubilar, J. F.; Gómez, I.; Narea, K.; Martínez, F.; Arriagada, C.; Le Roux, J.; Deckart, K.

    2015-12-01

    The classic Salar de Atacama Basin, located in the Central Andes of northern Chile, holds a remarkable yet not fully understood record of tectonic events since mid-Cretaceous times. Based on the growing amount of data collected over the last years, such as high-detail maps and U-Pb geochronology, we present an updated model for the development of this area after the Triassic. A major compressional event is recorded around the mid-Late Cretaceous (ca. 107 Ma) with the deposition of synorogenic continental successions reflecting the uplift of the Coastal Cordillera area farther to the west, and effectively initiating the foreland basin. The deformation front migrated eastwards during the Late Campanian (ca. 79 Ma), where it exhumed and deformed the Late Cretaceous magmatic arc and the crystalline basement of Cordillera de Domeyko. The K-T Event (ca. 65 Ma), recently identified in the basin, involved the same source areas, though the facies indicate a closer proximity to the source. The compressional record of the basin is continued by the Eocene Incaic Event (ca. 45 Ma), with deep exhumation of the Cordillera de Domeyko and the cannibalization of previous deposits. A change to an extensional regime during the Oligocene (ca. 28 Ma) is shown by the deposition of more than 4 km of evaporitic and clastic successions. A partial inversion of the basin occurred during the Miocene (ca.10 Ma-present), as shown by the deformation seen in the Cordillera de la Sal. As such, the basin shows that the uplift of the Cordillera de Domeyko was not one isolated episode, but a prolonged and complex event, punctuated by episodes of major deformation. It also highlights the need to take into account the Mesozoic-Cenozoic deformation events for any model trying to explain the building of the modern-day Andes.

  17. Syn-extensional lithogenetic sequences of the Soledad basin, central Transverse Ranges: Implications for detachment-fault models

    SciTech Connect

    Hendrix, E.D. )

    1993-04-01

    The Soledad Basin (central Transverse Ranges, CA) contains the first recognized example of mid-Tertiary detachment-faulting west of the San Andreas fault. Displacements along the Pelona detachment fault and syn-extensional upper-plate sedimentation occurred between [approximately] 26--18 Ma, resulting in deposition of at least 4 separate lithogenetic sequences (LS) which record distinct phases of crustal response to extension. The 1st LS (lower Vasquez Fm.) predates syn-extensional volcanism and records initial basin subsidence along small, discontinuous faults. The 2nd LS (middle Vasquez Fm.) consists of both volcanic and sedimentary strata and signals simultaneous onset of magmatism and initial development of a well-defined network of high-angle, upper-plate normal faults, creating 2 separate sub-basins. Resulting alluvial fans were non-entrenched, implying that subsidence rates, and thus vertical displacement rates on high-angle faults, equaled or exceeded an estimated average sedimentation rate of 1.4 mm/yr. The 3rd LS (upper Vasquez Fm.) reflects transition to a single, well-integrated depositional basin characterized by streamflood sedimentation. This suggests an enlarged drainage basin and a decrease in subsidence rate relative to sedimentation rate, triggered possibly by uplift of the detachment lower-plate. The 4th LS (Tick Canyon Fm.) lies with angular unconformity above the 3rd LS and contains the 1st clasts eroded from the detachment lower plate. Detachment faulting in the Soledad basin appears to involve, in part, reactivation of structural zones of weakness along the Vincent thrust. Preliminary reconstructions of Soledad extension imply 25--30 km of displacement along the Pelona detachment fault system at an averaged slip rate of 3.6--4.3 mm/yr.

  18. Exhumation of the Panama basement complex and basins: Implications for the closure of the Central American seaway

    NASA Astrophysics Data System (ADS)

    Ramírez, Diego A.; Foster, David A.; Min, Kyoungwon; Montes, Camilo; Cardona, Agustín.; Sadove, Gephen

    2016-05-01

    The emergence of the Central American isthmus occurred episodically from Eocene to Pliocene time and was caused by a series of tectonic and volcanic processes. Results from zircon U-Pb geochronology, zircon (U-Th)/He (ZHe) and apatite (U-Th)/He (AHe) thermochronology, and zircon Lu-Hf isotopic data from sedimentary (sandstones and recent river sands) and plutonic rocks from the Azuero Peninsula and Central Panama document the exhumation and uplift history of the Panamanian basement complex. Our data support previous paleobotanical and thermochronological studies that suggest that by middle Eocene time some areas of Central Panama and Azuero Peninsula were exposed above sea level as a series of islands surrounded by shallow open marine waters. The Gatuncillo, Cobachón and Tonosí formations were deposited during this partial emergence. Transtension in the Oligocene-early Miocene produced various pull-apart basins (e.g., the Canal Basin) and local uplift that exhumed the Eocene strata (Gatuncillo and Cobachón formations). This event probably reduced circulation between the Pacific Ocean and the Caribbean Sea. The Tonosí Formation records late Miocene to Pleistocene cooling and exhumation, which may be related to uplift above the subducting Coiba Ridge. These results suggest that the emergence of the Isthmus of Panama followed a series of diachronous events that led to the final closure of the Central American seaway.

  19. Seismic reflection evidence for two phase development of Tertiary basins from east-central Nevada

    SciTech Connect

    Liberty, L.M.; Heller, P.L.; Smithson, S.B. . Dept. of Geology and Geophysics)

    1993-04-01

    Two east-west seismic reflection profiles crossing Antelope Valley, Smokey Valley, Railroad Valley and Big Sand Springs Valley demonstrate the evolution of Tertiary extension from broad sags to narrow, fault-bounded basins. Seismic reflection data was acquired for the Anschutz Corporation by the Digicon Corporation during the winter of 1988/1989. Reprocessing of a 480 channel, 60 fold, dynamite source experiment enabled good imaging of the basin stratigraphy. These data suggest two distinct phases of basin development occurred, separated by a regional unconformity. The early phase is characterized by development of a broad basin riddled with many small offset normal faults. The later phase shows a narrowing of the basin and subsidence along one dominant structure, an apparent planar normal fault. The unconformity separating the two phases of extension marks a transition from broad subsidence to local asymmetric tilting that took place over a short period of time relative to sedimentation rates. Antelope Valley and Railroad Valley clearly show strong evidence for two phase development, whereas Smokey Valley represents mostly the early phase and Big Sand Springs Valley represents only the later phase of extension. The absence of dating within the basins precludes the authors from determining if the abrupt tectonic transition within the basins resulted from differences in local strain rates or amounts, or was due to changes in regional stress fields.

  20. Two-stage formation model of the Junggar basin basement: Constraints to the growth style of Central Asian Orogenic Belt

    NASA Astrophysics Data System (ADS)

    He, Dengfa

    2016-04-01

    Junggar Basin is located in the central part of the Central Asian Orogenic Belt (CAOB). Its basement nature is a highly controversial scientific topic, involving the basic style and processes of crustal growth. Some researchers considered the basement of the Junggar Basin as a Precambrian continental crust, which is not consistent with the petrological compositions of the adjacent orogenic belts and the crust isotopic compositions revealed by the volcanic rocks in the basin. Others, on the contrary, proposed an oceanic crust basement model that does not match with the crustal thickness and geophysical characteristics of the Junggar area. Additionally, there are several viewponits, such as the duplex basement with the underlying Precambrian crystalline rocks and the overlying pre-Carboniferous folded basement, and the collaged basement by the Precambrian micro-continent block in the central part and the Hercynian accretionary folded belts circling it. Anyway, it is necessary to explain the property of basement rock, its strong inhomogeneous compositions as well as the geophysical features. In this paper, based on the borehole data from more than 300 industry wells drilled into the Carboniferous System, together with the high-resolution gravity and magnetic data (in a scale of 1:50,000), we made a detailed analysis of the basement structure, formation timing and processes and its later evolution on a basis of core geochemical and isotopic analysis. Firstly, we defined the Mahu Pre-Cambrian micro-continental block in the juvenile crust of Junggar Basin according to the Hf isotopic analysis of the Carboniferous volcanic rocks. Secondly, the results of the tectonic setting and basin analysis suggest that the Junggar area incorporates three approximately E-W trending island arc belts (from north to south: Yemaquan- Wulungu-Chingiz, Jiangjunmiao-Luliang-Darbut and Zhongguai-Mosuowan- Baijiahai-Qitai island arcs respectively) and intervened three approximately E-W trending

  1. Understanding volcanism at the PETM: Abundant volcanic ash layers in the Central Tertiary Basin of Spitsbergen, Svalbard

    NASA Astrophysics Data System (ADS)

    Jones, Morgan; Eliassen, Gauti; Svensen, Henrik; Jochmann, Malte; Friis, Bjarki; Jerram, Dougal; Planke, Sverre

    2014-05-01

    During the early Tertiary, Svalbard developed a fold-thrust belt on its western margin with an associated foreland basin in the central-south of what is now Spitsbergen. This Central Tertiary Basin (CTB) is a syn-orogenic sedimentary basin in a strike-slip regime. The CTB contains the ~1900 m thick Van Mijenfjorden group, a dominantly sandstone-shale succession that was deposited in a North-South extending basin. Sediments in this group display evidence of major transgressive-regressive cycles related to local tectonics and eustatic sea level change. This basin is ideal for study as it has been extensively cored for coal prospecting, allowing a suite of sedimentary logs across the basin to be considered. Prominent marker beds in this sedimentary sequence are 1-30 cm thick bentonites, formed from the chemical weathering of volcanic tuff deposits. In this study, we focus on 8 sedimentary logs across the CTB, spanning the Palaeocene to lower Eocene in age. Bentonites are common in the Palaeocene cores (Basilika and Grumantbyen formations), while rarer but still occasionally present in the Eocene Frysjaodden formation. The cores had between 3-12 observable bentonite layers that showed large variations in preservation and subsequent reworking. Roots and other finer organic material were common, especially when the bentonites were found next to coal seams. Geochemical affinities between ash layers were investigated to identify basin-wide depositional events, with the aim of elucidating the provenance of these ashes. This sedimentary sequence is of broader interest as it covers the Palaeocene-Eocene thermal maximum (PETM), an extreme global warming event driven by large releases to the atmosphere of CO2 and/or CH4, evidenced by a negative carbon isotope excursion in both the ocean and atmosphere. Potential sources include volcanism and associated gas release from intruded sediments, CH4 hydrate dissociation, and/or the oxidation of organic matter. These formations are

  2. Hydrogeology and hydrogeochemistry at a site of strategic importance: the Pareja Limno-reservoir drainage basin (Guadalajara, central Spain)

    NASA Astrophysics Data System (ADS)

    Molina-Navarro, Eugenio; Sastre-Merlín, Antonio; Vicente, Rosa; Martínez-Pérez, Silvia

    2014-08-01

    A small calcareous basin in central Spain was studied to establish the role of groundwater in the Pareja Limno-reservoir. Limno-reservoirs aim to preserve a constant water level in the riverine zone of large reservoirs to mitigate the impacts arising from their construction. Groundwater flow contribution (mean 60 %) was derived by recharge estimation. In situ measurements (spring discharge, electrical conductivity and sulfate) were undertaken and spring discharge was compared with a drought index. Twenty-eight springs were monitored and three hydrogeological units (HGUs) were defined: a carbonate plateau (HGU1), the underlying aquitard (HGU2), and the gypsum-enriched HGU3. HGU1 is the main aquifer and may play a role in the preservation of the limno-reservoir water level. Hydrogeochemical sampling was conducted and the code PHREEQC used to describe the main geochemical processes. Weathering and dissolution of calcite and gypsum seem to control the hydrogeochemical processes in the basin. Water progresses from Ca2+-HCO3 - in the upper basin to Ca2+-SO4 2- in the lower basin, where HGU3 outcrops. A clear temporal pattern was observed in the limno-reservoir, with salinity decreasing in winter and increasing in summer. This variation was wider at the river outlet, but the mixing of the river discharge with limno-reservoir water buffered it.

  3. 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.

  4. Megabreccia deposits in an extensional basin: The Miocene-Pliocene Horse Camp Formation, east-central Nevada

    SciTech Connect

    Schmitt, J.G.; Brown, C.L. )

    1991-06-01

    Three varieties of megabreccia deposits are present in alluvial-lacustrine extensional basin fill of the Miocene-Pliocene Horse Camp Formation of east-central Nevada. Coherent debris sheets (150-300 m thick; up to 1,500 m long) consist of Oligocene-Miocene volcanic rock masses which are internally fractured yet retain their stratigraphic integrity. Fracture zones show variable amounts of displacement (up to 5 cm) and brecciation. These debris sheets overlie horizontally stratified sandstone and laminated claystone interpreted as playa deposits and are overlain by lithified grus. Emplacement of these coherent debris sheets was by landslide or block slide. Associated deposits of large boulders within playa facies suggest gliding of blocks broken from the edges of the landslides across wet playa surfaces. Large (1.6 - 2.4 km-long) allochthonous blocks consist of intact Paleozoic and Tertiary volcanic stratigraphic sequences which are brecciated and attenuated. Brecciation is accompanied in places by incorporation of muddy sand matrix. These blocks may be fragments of the upper plate of low-angle detachment faults which broke away as gravity-driven blocks from the nearby Horse Range and slid along the uplifted former detachment surface into the adjacent Horse Camp basin. Megabreccia deposits characterize Teritary extensional basins in western North America. Detailed analysis of their stratigraphic, sedimentologic, and structural relations can provide a better understanding of the complex tectonosedimentary history of these basins.

  5. A new interpretation of Stephanian deformation in the Decazeville basin (Massif Central, France): consequences on late Variscan tectonism

    NASA Astrophysics Data System (ADS)

    Basile, Christophe

    2006-09-01

    Five stages of faulting were observed in and around the Stephanian Decazeville basin, in the SW French Massif Central, at the southern edge of the Sillon houiller fault. The older stage ends during middle Stephanian time, and corresponds to a strike-slip regime with N-S shortening and E-W extension. Before the end of the middle Stephanian, three other stages were recorded: two strike-slip regimes with NW-SE, then E-W compression and NE-SW, then N-S extension; and finally a NNE-SSW extensional regime during the main subsidence of the basin from the end of the middle Stephanian to late Stephanian. Based on mining documents, a new interpretation of the N-S striking folds of the Decazeville basin is proposed. Folding may not be associated with E-W compression but with diapirism of coal seams along syn-sedimentary normal faults during the extensional phase. A last strike-slip regime with N-S compression and E-W extension may be related to Cainozoic Pyrenean orogeny. At a regional scale, it is suggested that from the end of the middle Stephanian to the late Stephanian, the main faults in the Decazeville basin may represent a horsetail splay structure at the southern termination of the Sillon houiller fault.

  6. Geochemical and detrital mode evidence for two sources of Early Proterozoic sedimentary rocks from the Tonto Basin Supergroup, central Arizona

    USGS Publications Warehouse

    Condie, K.C.; Noll, P.D., Jr.; Conway, C.M.

    1992-01-01

    The Tonto Basin Supergroup includes up to 6.5 km of Early Proterozoic sedimentary and volcanic rocks that were deposited in a relatively short period of time at about 1.7 Ga in central Arizona. Moderate correlations of rare earth elements (REE) and Ti with Al2O3 and REE distributions in detrital sediments of this supergroup suggest that these elements are contained chiefly in clay-mica and/or zircon fractions. REE distributions, including negative Eu anomalies in most Tonto Basin sediments, are similar to those in Phanerozoic shales. Weak to moderate correlations of Fe, Sc, Ni, and Co to Al2O3 also suggest a clay-mica control of these elements. Detrital modes and geochemical characteristics of sediments indicate two dominant sources for sedimentary rocks of the Tonto Basin Supergroup: a granitoid source and a volcanic source. The granitoid source was important during deposition of the upper part of the succession (the Mazatzal Group) as shown by increases in K2O, Al2O3, and Th in pelites with stratigraphic height, and increases in Zr and Hf and decreases in Eu/Eu*, Cr, and Ni in in pelites of the Maverick Shale. Sediment provenance characteristics and paleocurrent indicators are consistent with deposition of the supergroup in a continental-margin back-arc basin. The granitoid sediment source appears to have been the North American craton on the north, and the volcanic source a more local source from an arc on the south. ?? 1992.

  7. Constraints on the development of Proterozoic basins in central India from 40Ar/39Ar analysis of authigenic glauconitic minerals

    USGS Publications Warehouse

    Conrad, J.E.; Hein, J.R.; Chaudhuri, A.K.; Patranabis-Deb, S.; Mukhopadhyay, J.; Deb, G.K.; Beukes, N.J.

    2011-01-01

    Ages of some key stratigraphic sequences in central Indian Proterozoic basins are based predominantly on lithostratigraphic relationships that have been constrained by only a few radioisotopic dates. To help improve age constraints, single grains of glauconitic minerals taken from sandstone and limestone in two Proterozoic sequences in the Pranhita-Godavari Valley and the Chattisgarh basin were analyzed by the 40Ar/39Ar incremental heating method. Analysis of the age spectra distinguishes between ages that are interpreted to reflect the time of glauconite formation, and anomalous ages that result from inherited argon or postcrystallization heating. The analyses indicate an age of 1686 ± 6 Ma for the Pandikunta Limestone and 1566 ± 6 Ma for the Ramgundam Sandstone, two units in the western belt of Proterozoic sequences in Pranhita-Godavari Valley. Glauconite from the Chanda Limestone, in the upper part of this sequence, contains inherited 40Ar but is interpreted to reflect an age of ca. 1200 Ma. Glauconite from the Somanpalli Group in the eastern belt of the Pranhita-Godavari Valley gives an age of 1620 ± 6 Ma. In the Chattisgarh basin, glauconite from two units gives disturbed ages that suggest a period of regional heating in the Chattisgarh basin at ca. 960–1000 Ma. These new ages indicate that these sequences are 200–400 m.y. older than previously recognized, which has important implications for geochemical studies of Mesoproterozoic ocean redox conditions in addition to providing important constraints on regional tectonics and lithostratigraphy.

  8. Middle-Miocene counterclockwise rotation of rocks from west-central Nevada; implications for Basin and Range extension

    SciTech Connect

    Hudson, M.R.; Geissman, J.W.

    1985-01-01

    Drilling and geophysical data from Dixie Valley and Fallon Basin of west-central Nevada have shown that dip-slip normal faults accommodated post-Miocene Basin and Range extension in this area, but the presence of an earlier, less-understood phase of Basin and Range deformation is suggested in the adjacent West Humboldt, Stillwater, and Clan Alpine Ranges where the late-Miocene basalts lie in angular unconformity on Oligocene to early-Miocene ash-flow tuffs. Paleomagnetic components obtained from the tuffs and underlying gabbroic and basaltic rocks of the Jurassic Humboldt Lopolith have declinations that are statistically different and counterclockwise from the expected Oligo-Miocene and Jurassic directions for the area. Paleomagnetic components from the late-Miocene basalts statistically overlap their expected direction. These data imply that the rocks were rotated counterclockwise during middle-Miocene. The common association of such rotations with strike-slip faulting suggests that this earlier phase of Basin and Range extension was largely a strike-slip faulting deformation. If so, the total amount of extension in the area may be significantly larger than estimates based solely on the moderate tilts (<30/sup 0/) of the ranges.

  9. Geodynamic Drivers of Vertical Crustal Motion: Integrating Paleoaltimetry with Basin Development in the Central Andean Plateau of Southern Peru

    NASA Astrophysics Data System (ADS)

    Sundell, K. E., II; Saylor, J. E.; Lapen, T. J.; Villarreal, D. P.; Styron, R. H.; Horton, B. K.; Cardenas, J.

    2015-12-01

    Determining the spatial and temporal relationships between surface uplift, tectonic subsidence, and exhumation during periods of oblique crustal shortening is essential to discriminating geodynamic processes controlling formation of high topography in the central Andes. Although subsidence analysis is now a standard tool, paleoelevation estimation remains a challenging task, as estimates based on proxy data can be complicated by uncertainties in the relative controls of tectonics and climate. We therefore adopt an approach of combining established tools of subsidence analysis and detrital geochronology with emerging methods of volcanic glass paleoaltimetry, which enables us to explore a broad range of viable interpretations to understand the development of intermontane basins and their relationship to the development of the central Andean plateau. We investigated a suite of temporally overlapping and spatially separate Cenozoic basins spanning the east-west extent of the central Andean plateau in southern Peru. These basins contain an exceptional record of the vertical movements of this region. We calculate sediment accumulation and subsidence rates through decompaction of measured stratigraphic sections, and reconstruct past environmental conditions based on the stable isotopic composition of ancient waters preserved in hydrated volcanic glass. These data and published records of crustal shortening and exhumation show that although paleoaltimetry data in the study areas may be interpreted in various ways, they are best explained by multiple geodynamic processes driving (i) Eocene-early Miocene development of high topography in the Western Cordillera, then (ii) a pulsed middle Miocene-present building of the central Andean plateau from west to east, consistent with global climate changes as well as regional climate shifts driven by topographic development of the Andean orogen.

  10. New insights into the origin of late Neogene sediments in the Umatilla Basin, north-central Oregon and south-central Washington

    SciTech Connect

    Lindsey, K.A. ); Tolan, T.L. . Dept. of Geology); Reidel, S.P. )

    1993-04-01

    The study of late Miocene-aged terrigenous clastic sediments in the Umatilla Basin of north-central Oregon and adjacent Klickitat Valley of southern Washington reveal important, previously unrecognized stratigraphic and lithologic trends. These sediments, comprising the upper Ellensburg and the Alkali Canyon Formations (14 to 8.5 Ma) previously have been characterized as basaltic gravels deposited in localized alluvial fans and minor air fall tuffs produced by Cascade volcanism. A minor extrabasinal (exotic) component to these sediments has been noted in some previous studies. The authors' data challenges these interpretations. Pebble counts reveal a variety of exotic clast types, including metavolcanics, laminated metasediments, quartzites, and intermediate to silicic volcanics. This assemblage of lithologies is different than those that characterize the ancestral Columbia and Salmon-Clearwater Rivers. Sedimentologic trends suggest fluvial rather than alluvial fan deposition dominated. They interpret that a major fluvial system flowed from SE to NW across the western third of the Umatilla Basin. This river exited the Umatilla Basin via the Rock Creek water gap in the Columbia Hills, flowed across the Klickitat Valley and the Horse Heaven Hills, and then intersected the ancestral Columbia River. The abundance and stratigraphic distribution of exotic clast types suggests that this river drained terranes south and east of the Blue Mountains and persisted for a significant period of time, from approximately 14.5 to 8.5 Ma.

  11. 1990 Environmental Monitoring Report, Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Hwang, S.; Yeager, G.; Wolff, T.; Parsons, A.; Dionne, D.; Massey, C.; Schwartz, B.; Fish, J.; Thompson, D. ); Goodrich, M. )

    1991-05-01

    This 1990 report contains monitoring data from routine radiological and nonradiological environmental surveillance activities. Summaries of significant environmental compliance programs in progress such as National Environmental Policy Act (NEPA) documentation, environmental permits, environmental restoration, and various waste management programs for Sandia National Laboratories in Albuquerque (SNL, Albuquerque) are included. The maximum offsite dose impact was calculated to be 2.0 {times} 10{sup {minus}3} mrem. The total 50-mile population received a collective dose of 0.82 person-rem during 1990 from SNL, Albuquerque, operations. As in the previous year, the 1990 SNL operations had no adverse impact on the general public or on the environment. This report is prepared for the US Department of Energy in compliance with DOE Order 5400.1. 97 refs., 30 figs., 137 tabs.

  12. Digital tabulation of stratigraphic data from oil and gas wells in the Santa Maria Basin and surrounding areas, central California coast

    USGS Publications Warehouse

    Sweetkind, Donald S.; Tennyson, Marilyn E.; Langenheim, V.E.; Shumaker, Lauren E.

    2010-01-01

    Stratigraphic information from 694 oil and gas exploration wells from the onshore Santa Maria basin and surrounding areas are herein compiled in digital form from reports that were released originally in paper form. The Santa Maria basin is located within the southwesternmost part of the Coast Ranges and north of the western Transverse Ranges on the central California coast. Knowledge of the location and elevation of stratigraphic tops of formations throughout the basin is a first step toward understanding depositional trends and the structural evolution of the basin through time.

  13. The petroleum system of the lower Palaeozoic strata in the central part of the Baltic basin

    NASA Astrophysics Data System (ADS)

    Lazauskiene, Jurga; Zdanaviciute, Onyte

    2013-04-01

    The Baltic Basin is an intra-cratonic sedimentary basin with conspicuous Early Palaeozoic sections. In terms of hydrocarbon prospectively, the it has been perceived as a classical oil basin with several tens of relatively small oil and gas fields occur there over a wide stratigraphic interval, ranging from the crystalline basement through the entire Lower Palaeozoic succession. Until now conventional oil has been predominantly produced in the basin, i.e. only few conventional gas accumulations have been found in the Polish Baltic Sea offshore. Petroleum potential within the basin also is associated with Silurian reefogenic and carbonate build-ups. New organic geochemistry data as well revealed the potential for shale gas/oil in the basin. The analysis of the composition of the organic matter and crude oils from Kaliningrad region (Russia) and Lithuanian revealed genesis and the general trends of the migration of hydrocarbons in the Baltic Basin. The organic matter of the source rocks is of similar composition and represents typical marine type II, showing considerable variations of the maturity thought the basin: ranging from immature in the eastern Lithuania and Kaliningrad region of Russia to oil window to the south-west. In some places the anomalously high maturity of organic matter, indicating the lower part of the wet gas/condensate window have been recorded, most probably being related to the locally increased paleo-temperatures. Oils of the Baltic Basin have low densities (< 31,1 API; 790.5-870.0 kg/m3), and low asphaltene (<2.2%) and sulphur (<0.44%) contents. The saturated hydrocarbon content varies from 35.3 to 77.8%, and the ratio of saturate to aromatic hydrocarbons ranges in 2.1-5.2, indicating long-distance hydrocarbons migration or high thermal maturities. Oils of the Baltic Basin are not biodegraded, despite their early emplacement (e.g. by the Lower Palaeozoic age) and the relatively low present reservoir temperatures. Results of biomarker and

  14. 3D seismic geomorphology of mass transport complexes in a foredeep basin: Examples from the Pleistocene of the Central Adriatic Basin (Mediterranean Sea)

    NASA Astrophysics Data System (ADS)

    Dalla Valle, Giacomo; Gamberi, Fabiano; Rocchini, Patrizia; Minisini, Daniel; Errera, Alessia; Baglioni, Luca; Trincardi, Fabio

    2013-08-01

    Three-dimensional (3D) seismic-reflection data has shed light on the character of a series of mass transport complexes (MTCs) emplaced during the Pleistocene in the Pescara Basin (Central Adriatic Sea, Italy). The Pescara Basin is the Plio-Pleistocene inner foredeep of the Central Apennines orogen, which was filled by a rapidly prograding, margin-scale clinoforms system. Three MTCs punctuate the normal turbiditic and hemipelagic sedimentary succession of the Pescara Basin foredeep. MTC_0 is the oldest one and covers an area of around 74 km2. It is composed of three different mass transport deposits (MTDs) resulting from individual collapses that involved a shelf-edge delta during a period of relative sea level rise. MTC_1, the intermediate age MTC, is the largest one, with an area of 90 km2. It has a 10 km wide cookie-bite headwall region that indents the upper slope and, in places, reaches the continental shelf-break. MTC_1 is made up of four laterally and vertically stacked MTDs which are the result of a composite set of failures that migrated progressively upslope in a sedimentary setting dominated by contourite deposits. MTC_2 is the youngest and the smallest one, with an area of 55 km2. It has a 5 km long headwall confined in correspondence with a sedimentary bulge developed in the upper slope. Its geomorphic setting leads us to consider two different episodes of failure rooted at different depths. The investigation of the MTCs, through the coupling of 3D seismic geomorphology, seismic facies analysis and rollover trajectory analysis, reveals that the type of sedimentary environment, the rate of sediment accumulation, the source region and the depth of rooting of the failure, are the major controlling factors on MTC evolution and emplacement. Each MTC of the Pescara Basin foredeep is generally confined within a discrete clinotheme. Finally, the rollover trajectory analysis has shown that, in the PB foredeep, a sediment failure can possibly occur at any

  15. Identification and Tracking of Polluted Air Masses in the South-Central Coast Air Basin.

    NASA Astrophysics Data System (ADS)

    Moore, G. E.; Douglas, S. G.; Kessler, R. C.; Killus, J. P.

    1991-05-01

    Canister samples of air taken during the South-Central Coast Cooperative Air Monitoring Program (SCCCAMP) 1985 field study program were analyzed for concentrations of over 50 hydrocarbons as well as chlorofluorocarbons (CFCs), carbon monoxide, hydrogen, and methane. Additional evidence of location and timing of airmass origin was obtained by utilizing long-lived halocarbons such as F-12 as `tracers of opportunity' in conjunction with known source profiles. Wind trajectories were developed from hourly gridded wind fields produced by a diagnostic wind model utilizing observed wind data. These wind trajectories were used to determine how pollutants from major source areas might be transported to sampling sites. Particulate lidar height-distance traverses were made from aircraft that provided a view of pollutant layering. Mixing height and vertical pollutant concentration distributions were obtained in order to determine if observed pollutant concentrations were consistent with the degree of stagnation present and hypothesized transport pathway.Analyses to track specific polluted air masses were conducted for the 13 September, 21 September, 23-24 September, and 2-3 October 1985 intensive study periods. The analyses find that elevated ozone concentrations during these periods are primarily attributed to transport and storage of ozone-enriched air from Los Angeles. During one type of episode (2-3 October) ozone and ozone precursors are stored near the surface over the Santa Barbara Channel overnight and transported into coastal areas on the following day. In another type of episode (23-24 September) ozone is transported into the study domain from the San Fernando Valley and Los Angeles via flow around the Santa Monica Hills. Transport of pollutant-enriched air takes place in a layer 200-500 m aloft, in many places overlaying cleaner marine-layer air. This advected ozone is mixed down to contribute to ground-level ozone concentrations over terrain where the marine layer

  16. Computer aided graphics simulation modelling using seismogeologic approach in sequence stratigraphy of Early Cretaceous Punjab platform, Central Indus Basin, Pakistan

    SciTech Connect

    Qureshi, T.M.; Khan, K.A.

    1996-08-01

    Modelling stratigraphic sequence by using seismo-geologic approach, integrated with cyclic transgressive-regressive deposits, helps to identify a number of non-structural subtle traps. Most of the hydrocarbons found in Early Cretaceous of Central Indus Basin pertain to structural entrapments of upper transgressive sands. A few wells are producing from middle and basal regressive sands, but the massive regressive sands have not been tested so far. The possibility of stratigraphic traps like wedging or pinch-out, a lateral gradation, an uplift, truncation and overlapping of reservoir rocks is quite promising. The natural basin physiography at times has been modified by extensional episodic events into tectono-morphic terrain. Thus, seismo scanning of tectonically controlled sedimentation might delineate some subtle stratigraphic traps. Amplitude maps representing stratigraphic sequences are generated to identify the traps. Seismic expressions indicate the reservoir quality in terms of amplitude increase or decrease. The data is modelled on computer using graphics simulation techniques.

  17. Natural fractures and lineaments of the east-central Greater Green river basin. Topical report, May 1992-August 1995

    SciTech Connect

    Jaworowski, C.; Christiansen, G.E.; Grout, M.A.; Heasler, H.P.; Iverson, W.P.

    1995-08-01

    This topical report addresses the relationship of natural fractures and lineaments to hydrocarbon production of the east-central Greater Green River Basin. The tight gas sands of the Cretaceous Mesaverde Formation are the primary focus of this work. IER and USGS researchers have (1) demonstrated that east-northeast and northeast-trending regional fractures and lineaments are important to hydrocarbon production; (2) recognized the east-northeast regional joint set near two horizontal wells (Champlin 254 Amoco B 2-H and Champlin 320 C-1A-H) in the Washankie and Great Divide basins, respectively; (3) related Cretaceous Almond Formation thickness and facies to northeast-trending faults; (4) developed a program to automatically derive lineaments from small linear features; (5) associated oil and gas production data with east-northeast and northeast-trending lineaments and linear features; and (6) digitally compared lineaments with potentiometric maps of the Mesaverde and Frontier formations.

  18. New insights into the structure of Om Ali-Thelepte basin, central Tunisia, inferred from gravity data: Hydrogeological implications

    NASA Astrophysics Data System (ADS)

    Harchi, Mongi; Gabtni, Hakim; El Mejri, Hatem; Dassi, Lassaad; Mammou, Abdallah Ben

    2016-08-01

    This work presents new results from gravity data analyses and interpretation within the Om Ali-Thelepte (OAT) basin, central Tunisia. It focuses on the hydrogeological implication, using several qualitative and quantitative techniques such as horizontal gradient, upward continuation and Euler deconvolution on boreholes log data, seismic reflection data and electrical conductivity measurements. The structures highlighted using the filtering techniques suggest that the Miocene aquifer of OAT basin is cut by four major fault systems that trend E-W, NE-SW, NW-SE and NNE-SSW. In addition, a NW-SE gravity model established shows the geometry of the Miocene sandstone reservoir and the Upper Cretaceous limestone rocks. Moreover, the superimposition of the electrical conductivity and the structural maps indicates that the low conductivity values of sampled water from boreholes are located around main faults.

  19. 1983 environmental monitoring report, Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Millard, G.C.; Gray, C.E.; O'Neal, B.L.

    1984-04-01

    Sandia National Laboratories (SNL) is located south of Albuquerque on Kirtland Air Force Base. Because radionuclides are potentially released from its research activities, SNL has a continuing environmental monitoring program which analyzes for cesium-137, tritium, uranium, alpha emitters, and beta emitters in water, soil, air, and vegetation. Measured radiation levels in public areas were consistent with local background in 1983. The Albuquerque population received an estimated 0.250 person-rem from airborne radioactive releases, whereas it received greater than 49,950 person-rem from naturally occurring radionuclides. 23 references, 6 figures, 15 tables.

  20. Geologic and isostatic map of the Nenana Basin area, central Alaska

    USGS Publications Warehouse

    Frost, G.M.; Barnes, D.F.; Stanley, R.G.

    2002-01-01

    Introduction The Nenana Basin area is a prospective petroleum province in central Alaska, and this geologic and isostatic gravity map is part of a petroleum resource assessment of the area. The geology was compiled from published sources (Chapman and others, 1971, 1975a, 1975b, 1982; Chapman and Yeend, 1981; Csejtey and others, 1986; Jones and others, 1983; Pewe and others, 1966; Reed, 1961; and Weber and others, 1992), as shown on the index map (map sheet). Map units are organized and presented according to the scheme of lithotectonic terranes proposed by Jones and others (1987) and Silberling and Jones (1984); we recognize, however, that this terrane scheme is controversial and likely to be revised in the future. In some cases, we combined certain terranes because we were unable to match the terrane boundaries given by Jones and others (1987) and Silberling and Jones (1984) with specific faults shown on existing geologic maps. Postaccretion cover deposits represent overlap assemblages that depositionally overlie accreted terranes. Plutonic igneous rocks shown on this map include several plutons that are clearly postaccretionary, based on isotopic ages and (or) field relations. It is possible that some of the plutons predate accretion, but this has not been demonstrated. According to Jones and others (1982), the terranes in the area of our map were assembled during late Mesozoic or earliest Cenozoic time. The gravity contours are derived from data used in earlier compilations (Barnes, 1961, 1977; Hackett, 1981; Valin and others, 1991; Frost and Stanley, 1991) that are supplemented by some National Oceanic and Atmospheric Administration data along the Alaska Pipeline level line (W.E. Strange, written commun., 1980). The earlier compilations were used for simple Bouguer maps, prepared primarily by non-digital methods, and are superseded by this map. The present map is the result of digital processing that includes the 1967 Geodetic Reference System, the IGSN-71

  1. Basin development and compressional deformation in the central High Atlas Mountains northwest of Errachidia (Morocco) - rejuvenated tectonics

    SciTech Connect

    Brede, R.

    1988-08-01

    The development of the central High Atlas Mountains from the Triassic until today was controlled by a set of pre-existent basement faults which were reactivated in various manners. During the Triassic a graben began to subside at the northwestern border of the African craton. The graben's development was at least temporarily linked to the opening of the Atlantic Ocean. The growing basin was filled by red detrital material from the adjacent elevated regions. Evaporites were only locally formed. Mostly the red beds show an intercalation of basic volcanics. During the early and middle Liassic, a shallow shelf with reefs existed at the southern rim of the Atlas-Gulf, from which much carbonate material was delivered into the basin. This deposition is proved by turbiditic limestones of considerable thickness in the Pliensbachian. After a further deepening of the Atlas-Gulf in the late Liassic and the early Dogger, a trend toward shallowing began in the Bajocian, enabling reefs to grow from the south into the basin. Toward the end of the middle Dogger, the trough began to fill with red detrital material. This period of red-bed sedimentation lasted until the early part of the late Cretaceous and had abundant intercalation of gypsum near the top of the sequence. Due to a transgression a short marine period followed, documented by the Cenomanian-Turonian limestones. This marine period was succeeded again by the deposition of red beds in the middle of late Cretaceous. The Jurassic sediments are sometimes penetrated by small doleritic dikes. The development of the basin was controlled by east-northeast-striking faults. During compression in the Tertiary, the /sigma//sub 3/ direction (north-northwest) of the Mesozoic basin development changed into the /sigma//sub 1/ direction of compressional deformation and the synsedimentary normal faults were reactivated as upthrusts.

  2. Quaternary landscape evolution driven by slab-pull mechanisms in the Granada Basin (Central Betics)

    NASA Astrophysics Data System (ADS)

    Pérez-Peña, J. V.; Azañón, J. M.; Azor, A.; Booth-Rea, G.; Galve, J. P.; Roldán, F. J.; Mancilla, F.; Giaconia, F.; Morales, J.; Al-Awabdeh, M.

    2015-11-01

    The Granada Basin is one of the largest Neogene-Quaternary intramontane basins of the Betic Cordillera in SE Spain. The landscape evolution in this basin is complex and does not respond to a simple model of headward erosion following river capture of a former endorheic catchment. In the NE border of the basin, the drainage network is highly incised and reveals two different stages of river development since the Pleistocene. The older drainage network presents low incision, being locally controlled by ENE-WSW open folds. The present-day drainage network features deep incised valleys with a well-defined local base-level controlled by NW-SE normal faults. The ENE-WSW open folds were generated by compressional stresses and affect a geomorphic surface that caps the local sedimentary sequence. These folds are thought to reactivate a Pliocene roll-over formed in the hanging wall of ENE-WSW normal faults that bound the Granada Basin to the north and the deepest Pliocene depocenter. On the contrary, Quaternary depocenters are located in the hanging wall of the NW-SE-oriented normal faults that control the present-day drainage network (NW-SE oriented). The activity of these faults also contributes to the erosion of the Pliocene depocenter located to the north, thus suggesting a southwestward migration of the loci of extension to the center of the basin. The broad-scale scenario envisaged to explain the Pliocene-Quaternary evolution of the NE border of the Granada Basin is one dominated by mantle slab-pull coeval with the Africa-Iberia continuous convergence.

  3. Spatial analysis of soil and shallow groundwater physicochemical parameters in El-Mujib Basin-central Jordan

    NASA Astrophysics Data System (ADS)

    Salman, Abeer; Al-Qinna, Mohammed; Kuisi, Mustafa Al

    2014-01-01

    In this study statistical and geostatistical methods were applied to a monitoring data set in order to assess contamination risk in soil and shallow groundwater. The study covered an area within El-Mujib Basin in central Jordan, where the barren land is dominating with a small number of irrigated areas in the vicinity of Wadi El-Mujib and in the northern part of the basin. A total of 77 soil and 104 water samples were collected randomly and analyzed physically, chemically, statistically and spatially using ordinary and indicator kriging techniques. Phosphate, nitrate, organic matter and effective field capacity in the soil system were spatially investigated and correlated to current landuse. Maximum soil maximum nitrate (125.6 mg/L), phosphate (9.7 mg/L), and organic matter (3%) contents are encountered in the central area at Wadi El-Mujib, Qattrana and Umm Rasas due to the use of fertilizers and existence of solid landfill. The soil has low water holding capacity as it is dominated by coarse texture and therefore subjecting the groundwater for potential risks through the fast soil system. The major cations and anions in the groundwater were mainly concentrated in the Wadi El-Mujib and in the central part of the Basin increases along the groundwater flow direction. Spatial groundwater indicator maps of salinity; nitrate and sulfate contents proves the high susceptibility of the study area to be contaminated. By determining the impacts, more effective (specific to contamination sources) measures for preventing groundwater quality could be implemented.

  4. Imaging of the seismogenic source fault in the fold-and-thrust belt, Niigata basin, central Japan

    NASA Astrophysics Data System (ADS)

    Kato, N.; Sato, H.; Abe, S.; Kawai, N.; Saito, H.; Iwasaki, T.; Shiraishi, K.; Ishiyama, T.; Inaba, M.

    2010-12-01

    Associated with the opening of the Japan Sea, volcanic rift-basins have been developed along the Japan Sea coast of northern Honshu. The Niigata basin, central Japan, is one of such basins and filled by thick (< 7 km) Neogene sediments. By subsequent convergence since the Pliocene, an arc-parallel fold-and-thrust-belt has been developed along the Miocene rift-basins. In this belt devastative earthquakes, such as 1964 Niigata (M7.5), 2004 Chuetsu (M6.8) and 2007 Chuetsu-oki (M6.8) earthquakes, occurred by reverse faulting. Due to thick Neogene sediments, relationship between active faults/folds at near the surface and deep-sited seismogenic source faults is poorly understood. To reveal the crustal structure, in particular geometry of source faults, onshore-offshore integrated deep seismic profiling was undertaken along the three seismic lines in 2008, 2009 and 2010. The 2009 Aizu-Sado Seismic line is a 135-km-long, onshore-offshore seismic line across Niigata basin and Sado island, which is located in the eastern part of Japan Sea. The 2008 Sanjo-Yahiko Seismic line is located 20 km south of the seismic line and trending parallel to it. The 2010 Higashiyama-Mishima seismic line cut through the northern part of the epicentral area of the 2007 Chuetsu-oki earthquake. The seismic sources were air-gun (3020 cu. inch), four vibroseis trucks and explosives (< 200 kg). Along the Sado strait, seismic data was acquired using two-ships to make large offset shot gathers. Seismic signals were recorded by ocean bottom cables, cable-connected-recording system and offline recorders, forming a maximum 2400 channels receiver array. The basin fill consists of early to middle Miocene volcaniclastic rocks and overlying Neogene sedimentary rocks showing upward coarsening facies deposited under bathyal to fluvial environment. Main features of basin development, such as early Miocene normal faulting, associated with the formation of Japan Sea, and shortening deformation since the Pliocene

  5. Structural style of the Cuyo-Bolsones basin complex of west-central Argentina

    SciTech Connect

    Gollop, I.G. )

    1991-03-01

    The Cuyo-Bolsones basin complex is part of a mosaic of basinal features that lie in the eastern Andean foreland. Sedimentary section ranges from Ordovician to Tertiary in age with the main petroleum source and reservoir potential in Carboniferous to Triassic clastics. Thick conglomerate units and widespread unconformities of both Permo-Carboniferous and Triassic age as well as localized volcanics indicate several periods of violent tectonic activity during late Paleozoic to early Mesozoic times. Triassic and older sediments are affected by normal faulting which in basins directly south extends up into the Lower Cretaceous. In the Cuyo-Bolsones basinal area, however this ancient tensional regime is entirely overprinted by relatively recent thrusting. This thrusting is late Tertiary in age, generally from east to west with very substantial relief. These thrust sheets are cut in places by later northeast-southwest strike-slip fault zones producing some localized flower structures. Nearly all the oil discovered in the Cuyo basin is produced from Triassic clastic reservoirs in compressional anticlines related to this thrusting. The major thrusts are well defined seismically, and seismic interpretations fit easily on balanced sections.

  6. Wellbore stability analysis and its application in the Fergana basin, central Asia

    NASA Astrophysics Data System (ADS)

    Chuanliang, Yan; Jingen, Deng; Baohua, Yu; Hailong, Liu; Fucheng, Deng; Zijian, Chen; Lianbo, Hu; Haiyan, Zhu; Qin, Han

    2014-02-01

    Wellbore instability is one of the major problems hampering the drilling speed in the Fergana basin. Comprehensive analysis of the geological and engineering data in this area indicates that the Fergana basin is characterized by high in situ stress and plenty of natural fractures, especially in the formations which are rich in bedding structure and have several high-pressure systems. Complex accidents such as wellbore collapse, sticking, well kick and lost circulation happen frequently. Tests and theoretical analysis reveals that the wellbore instability in the Fergana basin was influenced by multiple interactive mechanisms dominated by the instability of the bedding shale. Selecting a proper drilling fluid density and improving the sealing characteristic of the applied drilling fluid is the key to preventing wellbore instability in the Fergana basin. The mechanical mechanism of wellbore instability in the Fergana basin was analysed and a method to determine the proper drilling fluid density was proposed. The research results were successfully used to guide the drilling work of the Jida-4 well; compared with the Jida-3 well, the drilling cycle of the Jida-4 well was reduced by 32%.

  7. Extension in the Colorado Plateau/Basin and Range Transition Zone, Central Utah: An Active or Passive Process?

    NASA Astrophysics Data System (ADS)

    Hasterok, D.; Wannamaker, P. E.; Chapman, D. S.; Doerner, W.

    2007-12-01

    The Colorado Plateau-Great Basin transition zone (TZ) in central Utah is a presently extending lithospheric block composed of previously stable Proterozoic lithosphere. TZ extension may be driven by high topography resulting from overthickening during the Laramide Orogeny and passive plate boundary forces similar to the Great Basin. However, high TZ topography coupled with a thinned lithosphere may indicate dynamic mantle upwelling and active processes acting within the TZ. To investigate the active vs. passive rifting hypotheses we have collected 56 new broadband and 9 long-period MT stations to merge two existing MT lines for a combined length of 400~km (124 sites) covering the eastern Great Basin into the Colorado Plateau at a latitude of ~38.5°N. We have also collected over 300 new heat production and thermal conductivity measurements across the southwest to develop a thermal model of the eastern Basin and Range and Colorado Plateau. MT data show a semi-contiguous highly conductive body in the lower crust of the eastern Great Basin that rises to a shallow depth of <20~km beneath the TZ. This conductive layer appears to be connected to the surface by a series of symmetric rift related normal faults mapped at the surface. These normal faults may be acting as pathways for large-scale fluid connection between the upper and lower crust. MT inversion results suggest an electrical anisotropy factor >3 in the upper mantle with an enhanced conductivity in a N-S orientation that is in agreement with observations of fast seismic SKS split direction. We propose that anisotropy observations may be due to small degrees of interconnected partial melt aligned with a N-S geologic strike beneath the Basin and Range. A thermal model, combining measured thermophysical properties with existing heat flow data, MT measurements, and estimates of seismogenic depth is used to predict lithospheric thickness and mantle temperature variations along the MT profile. Lithospheric thicknesses

  8. Solute load concentrations in some streams in the Upper Osun and Owena drainage basins, central western Nigeria

    NASA Astrophysics Data System (ADS)

    Jeje, L. K.; Ogunkoya, O. O.; Oluwatimilehin, J. M.

    1999-12-01

    The solute load dynamics of 12 third-order streams in central western Nigeria are presented, during storm and non-storm runoff events. The relevance of the Walling and Foster model for explaining storm period solute load dynamics in the humid tropical environment was assessed and it was found that this model was generally applicable to the study area. Exceptions appear to be streams draining settlements and/or farms where fertilizers are applied heavily. The solute load ranged from 5 mg l -1 to 580 mg l -1 with streams draining basins with tree-crop plantations ( Theobroma cacao, Cola sp.) as the dominant land cover having the highest solute load.

  9. The tomato borer, Tuta absoluta, invading the Mediterranean Basin, originates from a single introduction from Central Chile

    PubMed Central

    Guillemaud, Thomas; Blin, Aurélie; Le Goff, Isabelle; Desneux, Nicolas; Reyes, Maritza; Tabone, Elisabeth; Tsagkarakou, Anastasia; Niño, Laura; Lombaert, Eric

    2015-01-01

    The Lepidopteran pest of tomato, Tuta absoluta, is native to South America and is invasive in the Mediterranean basin. The species' routes of invasion were investigated. The genetic variability of samples collected in South America, Europe, Africa and Middle East was analyzed using microsatellite markers to infer precisely the source of the invasive populations and to test the hypothesis of a single versus multiple introductions into the old world continents. This analysis provides strong evidence that the origin of the invading populations was unique and was close to or in Chile, and probably in Central Chile near the town of Talca in the district of Maule. PMID:25667134

  10. Evidence of Quaternary rock avalanches in the central Apennines: new data and interpretation of the huge clastic deposit of the L'Aquila basin (central Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Esposito, Carlo; Scarascia Mugnozza, Gabriele; Tallini, Marco; Della Seta, Marta

    2014-05-01

    Active extensional tectonics and widespread seismicity affect the axial zone of the central Apennines (Italy) and led to the formation of several plio-quaternary intermontane basins, whose morpho-evolution was controlled by the coupling of tectonic and climatic inputs. Common features of the Apennines intermontane basins as well as their general morpho-evolution are known. Nonetheless, the complex interaction among regional uplift, local fault displacements and morpho-climatic factors caused differences in the denudational processes of the single intermontane basins. Such a dynamic response left precious records in the landscape, which in some cases testify for the occurrence of huge, catastrophic rock slope failures. Several Quaternary rock avalanches have been identified in central Apennines, which are often associated with Deep Seated Gravitational Slope Deformation (DSGSD) and thus strictly related to the geological-structural setting as well as to the Quaternary morpho-structural evolution of the mountain chain. The L'Aquila basin is one of the intermontane tectonic depression aligned along the Middle Aterno River Valley and was the scene of strong historical earthquakes, among which the last destructive event occurred on April 6, 2009 (Mw 6.3). We present here the evidence that the huge clastic deposit on which the city of L'Aquila was built up is the body of a rock avalanche detached from the southern slope of the Gran Sasso Range. The clastic deposit elongates for 13 km to the SW, from the Assergi Plain to L'Aquila and is characterized by typical morphological features such as hummocky topography, compressional ridges and run-up on the opposite slope. Sedimentological characters of the deposit and grain size analyses on the matrix let us confirm the genetic interpretation, while borehole data and significant cross sections allowed us reconstructing the 3D shape and volume of the clastic body. Finally, morphometric analyses of the Gran Sasso Range southern

  11. Core drilling provides information about Santa Fe Group aquifer system beneath Albuquerque's West Mesa

    USGS Publications Warehouse

    Allen, B.D.; Connell, S.D.; Hawley, J.W.; Stone, B.D.

    1998-01-01

    Core samples from the upper ???1500 ft of the Santa Fe Group in the Albuquerque West Mesa area provide a first-hand look at the sediments and at subsurface stratigraphic relationships in this important part of the basin-fill aquifer system. Two major hydrostratigraphic subunits consisting of a lower coarse-grained, sandy interval and an overlying fine-grained, interbedded silty sand and clay interval lie beneath the water table at the 98th St core hole. Borehole electrical conductivity measurements reproduce major textural changes observed in the recovered cores and support subsurface correlations of hydrostratigraphic units in the Santa Fe Group aquifer system based on geophysical logs. Comparison of electrical logs from the core hole and from nearby city wells reveals laterally consistent lithostratigraphic patterns over much of the metropolitan area west of the Rio Grande that may be used to delineate structural and related stratigraphic features that have a direct bearing on the availability of ground water.

  12. Builders Challenge High Performance Builder Spotlight - Artistic Homes, Albuquerque, NM

    SciTech Connect

    2009-01-01

    Building America Builders Challenge fact sheet on Artistic Homes of Albuquerque, New Mexico. Describes the first true zero E-scale home in a hot-dry climate with ducts inside, R-50 attic insulation, roof-mounted photovoltaic power system, and solar thermal water heating.

  13. Evaluation of the Albuquerque Indian School Motivational Environment Program.

    ERIC Educational Resources Information Center

    Hiat, Albert B.; And Others

    In order to evaluate the impact of a token economy behavior modification program implemented from 1970-71 in the Albuquerque Indian School (AIS), a secondary institution, a five-member evaluation team assessed standardized test results, behavioral data, and student and staff attitudes. A battery of tests (Tennessee Self-Concept Scale, SRA…

  14. Wastewater reclamation and recharge: A water management strategy for Albuquerque

    SciTech Connect

    Gorder, P.J.; Brunswick, R.J.; Bockemeier, S.W.

    1995-12-31

    Approximately 61,000 acre-feet of the pumped water is annually discharged to the Rio Grande as treated wastewater. Albuquerque`s Southside Water Reclamation Plant (SWRP) is the primary wastewater treatment facility for most of the Albuquerque area. Its current design capacity is 76 million gallons per day (mgd), which is expected to be adequate until about 2004. A master plan currently is being prepared (discussed here in Wastewater Master Planning and the Zero Discharge Concept section) to provide guidelines for future expansions of the plant and wastewater infrastructure. Construction documents presently are being prepared to add ammonia and nitrogen removal capability to the plant, as required by its new discharge permit. The paper discusses water management strategies, indirect potable reuse for Albuquerque, water quality considerations for indirect potable reuse, treatment for potable reuse, geohydrological aspects of a recharge program, layout and estimated costs for a conceptual reclamation and recharge system, and work to be accomplished under phase 2 of the reclamation and recharge program.

  15. RESPECT: Gang Mediation at Albuquerque, New Mexico's Washington Middle School.

    ERIC Educational Resources Information Center

    Tabish, Kenneth R.; Orell, Linda Henry

    1996-01-01

    Presents conflict resolution and mediation techniques used to resolve conflicts among rival gangs at Washington Middle School, an inner-city school in Albuquerque, New Mexico. Discusses formal mediation techniques and mediation for both male and female gang members. Focuses on preserving self-respect and dignity for gang members in all conflict…

  16. 1995 Site environmental report Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Shyr, L.J.; Duncan, D.; Sanchez, R.

    1996-09-01

    This 1995 report contains data from routine radiological and non-radiological environmental monitoring activities. Summaries of significant environmental compliance programs in progress, such as National Environmental Policy Act documentation, environmental permits, environmental restoration and various waste management programs at Sandia National Laboratories in Albuquerque, New Mexico, are included.

  17. Seasonal and spatial contrasts of sedimentary organic carbon in floodplain lakes of the central Amazon basin.

    NASA Astrophysics Data System (ADS)

    Sobrinho, Rodrigo; Kim, Jung-Hyun; Abril, Gwenaël; Zell, Claudia; Moreira-Turcq, Patricia; Mortillaro, Jean-Michel; Meziane, Tarik; Damsté, Jaap; Bernardes, Marcelo

    2014-05-01

    Three-quarters of the area of flooded land in the world are temporary wetlands (Downing, 2009), which play a significant role in the global carbon cycle(Einsele et al., 2001; Cole et al., 2007; Battin et al., 2009; Abril et al., 2013). Previous studies of the Amazonian floodplain lakes (várzeas), one important compartment of wetlands, showed that the sedimentation of organic carbon (OC) in the floodplain lakes is strongly linked to the periodical floods and to the biogeography from upstream to downstream(Victoria et al., 1992; Martinelli et al., 2003). However, the main sources of sedimentary OC remain uncertain. Hence, the study of the sources of OC buried in floodplain lake sediments can enhance our understanding of the carbon balance of the Amazon ecosystems. In this study, we investigated the seasonal and spatial pattern of sedimentary organic matter in five floodplain lakes of the central Amazon basin (Cabaliana, Janauaca, Canaçari, Miratuba, and Curuai) which have different morphologies, hydrodynamics and vegetation coverage. Surface sediments were collected in four hydrological seasons: low water (LW), rising water (RW), high water (HW) and falling water (FW) in 2009 and 2010. We investigated commonly used bulk geochemical tracers such as C:N ratio and stable isotopic composition of organic carbon (δ13COC). These results were compared with lignin-phenol parameters as an indicator of vascular plant detritus (Hedges and Ertel, 1982) and branched glycerol dialkyl glycerol tetraethers (brGDGTs) to trace the soil OC from land to the aquatic settings (Hopmans et al., 2004). Our data showed that during the RW and FW seasons, the concentration of lignin and brGDGTs were higher in comparison to other seasons. Our study also indicated that floodplain lake sediments primarily consisted of a mixture of C3 plant detritus and soil OC. However, a downstream increase in C4 plant-derived OC contribution was observed along the gradient of increasingly open waters, i

  18. Sediment Dynamics in the Upper McKenzie River Basin, Central Oregon Cascade Range

    NASA Astrophysics Data System (ADS)

    Stallman, J. D.; Bowers, R. J.; Cabrera, N. C.; Real de Asua, R.; Wooster, J. K.

    2005-12-01

    Reference and current sediment budgets were developed to evaluate the extent to which hydroelectric dams alter sediment dynamics in the upper McKenzie River basin of central Oregon. The 647 km2 study area straddles the western boundary of the High Cascades graben separating the High Cascades and Western Cascades geologic terrains. Permeable Quaternary volcanics forming the low-gradient High Cascades plateau promote surface hydrologic disconnection, nearly constant discharge controlled by groundwater emergence, and low sediment yield. In contrast, deeply weathered Tertiary volcanics, rugged topography, and a dense network of steep channels in the Western Cascades terrain promote peaked storm responses and high sediment yield by deep-seated mass movement, debris slides, and debris flows. Three independent estimates of sediment yield (application of published surface process rates, extrapolation of regional suspended load and bedload flux rates, and extrapolation of reservoir sedimentation rates) illustrate the dominant role of geologic terrains in determining the longitudinal pattern of sediment supply to the McKenzie River. Average reference yields from High Cascades and Western Cascades sources were 9 t km-2y-1 and 200 t km-2y-1, respectively. Downstream of Trail Bridge Dam, High Cascades sources (241 km2) account for 12% of the total reference yield, while Western Cascades sources (67 km2) account for 62%. Estimates of current sediment yield illustrate the offsetting effects of reservoir sediment trapping and accelerated yield related to forest management. Average current yields from High Cascades and Western Cascades sources were 17 t km-2y-1 and 300 t km-2y-1, respectively. Current yield to the McKenzie River arm of Trail Bridge Reservoir (42 km2 sourced in High Cascades terrain) was 17 t km-2y-1, while current yield to Smith Reservoir (48 km2 sourced in Western Cascades terrain) was 251 t km-2y-1. The relation between hydroelectric project effects and forest

  19. Evolution of the Lower Cretaceous Coqen basin in northern Lhasa, central Tibet Plateau: stratigraphy, sedimentology, and detrital zircon geochronology

    NASA Astrophysics Data System (ADS)

    Sun, Gaoyuan; Hu, Xiumian; Sinclair, Hugh; BouDagher-Fadel, Marcelle

    2016-04-01

    potential sources, the Zelong volcanic rocks and the pre-Carboniferous strata within the northern part of the Lhasa terrane are the most possible sources for the Duoni Formation. The evolution of the Early Cretaceous Coqen basin can be indivied into two stags. During Aptian time (~123-115 Ma), the Duoni Formation received materials southward from the Zelong volcanic rocks and the sedimentary basement rocks in the central Lhasa terrane. The basin developed in a retro-arc setting related to the northward subduction of Neo-tethyan oceanic lithosphere, resulting in the occurrence of the Zelong volcanics arc meanwhile. Our data are inconsistent with the foreland basin related to the Lhasa-Qiangtang collision in the north as previous interpreted. During latest Aptian-earliest Cenomanian (~115-98 Ma), the Coqen basin was prevailed by the shallow marine Langshan limestone, developed in a sag basin that developed in the retro side of the Neo-tethyan oceanic lithosphere subduction. The mechinism of this sag basin was the dynamic subsidence resulted from the low-angle or flatted subduction of the Neo-tethyan oceanic lithosphere during this time interval.

  20. Seafloor structure and uppermost sedimentation in the Pigafetta Basin, Magellan Seamount Chain, and East Mariana Basin of the Central-Western Pacific

    NASA Astrophysics Data System (ADS)

    Mathews, N. J.; Oakley, A. J.; Lizarralde, D.; Tominaga, M.; Tivey, M.; Sager, W. W.

    2013-12-01

    We conducted a marine geophysical survey of the Central-Western Pacific seafloor in 2011 aboard the R/V Thomas G. Thompson (TN272). Our survey imaged some of the oldest seafloor on the planet in a region of sparse data coverage. We present new (3.5 kHz) and bathymetry data from the Mesozoic Hawaiian magnetic lineations (Jurassic Quiet Zone) and a transect from the south end of the Pigafetta Basin (PB), west across the Magellan Seamount Chain (MSC) and the East Mariana Basin (EMB) to the Mariana Trench. The Chirp system penetrates the overlying sediment cover to a depth of ~50 meters below seafloor (mbsf). The deepest part of the Chirp record is marked by a strongly reflecting horizon, which occasionally crops out at the seafloor near volcanic peaks or bathymetric highs. Correlation of these data to DSDP/ODP drill sites (801C, 802, 199, 585) enables us to compare seafloor structure and uppermost sedimentation in the Jurassic Quiet Zone (JQZ), Pigafetta Basin, Magellan Seamounts, and the East Mariana Basin. Within the JQZ, and at the southern end of the PB, a 30- to 50-m-thick, acoustically-transparent sediment layer uniformly overlies the strongly reflecting horizon observed at water depths ranging from 4400m-5900m. We interpret this unit to be composed of pelagic abyssal clay and radiolarian oozes ubiquitous in the central-western Pacific. The basal horizon in this region is most likely formed by a layer of chert-porcelanite. In the southeastern PB (161.3 E, 17 N), this horizon reaches the seafloor at a depth of 5650 m and the transparent sediment package is truncated. In the region of the MSC, ~115 km north of drill sites 199 and 585, Chirp data show numerous volcanic peaks and a 50-m-thick sequence of stratified reflections. Volcaniclastics likely contribute to the layering. We first observe the stratified sediment package near 156.7 E, 15 N after a gap in data coverage. The sediment layer thins to the west and onlaps the basal horizon near the base of a seamount

  1. Postglacial response of a stream in central Iowa to changes in climate and Drainage basin factors*1

    NASA Astrophysics Data System (ADS)

    Van Nest, Julieann; Bettis, E. Arthur

    1990-01-01

    Postglacial geomorphic development of the Buchanan Drainage, a small tributary to the South Skunk River, is reconstructed by documenting relationships among four allostratigraphic units and 17 radiocarbon dates. Formation and headward expansion of the valley was both episodic and time-transgressive. Response to downstream conditions in the South Skunk River largely controlled the early formation of the basin. Downcutting through Pleistocene deposits produced a gravelly lag deposit that was buried by alluvium in the downstream portion of the valley during the early Holocene (10,500-7700 yr B.P.). Lag deposits formed in a similar manner continued to develop in the upper portion of the drainageway into the late Holocene (3000-2000 yr B.P.). Episodes of aggradation during the middle Holocene (7700-6300 yr B.P.) and late Holocene (3000-2000 yr B.P.) were separated by a period of soil formation. Holocene geomorphic events in the drainageway coincide with some vegetational and climatic changes as documented in upland pollen sequences from central Iowa. Analysis of plant macrofossil assemblages recovered from alluvium indicates that during the middle Holocene forest contracted and prairie expanded into the uplands within the basin. Vegetational changes within the basin apparently had only minor influence on rates of hillslope erosion, and the widely accepted relationship between prairie (versus forest) vegetative cover and increased rates of hillslope erosion did not hold. Instead, greater amounts of erosion occurred under forested conditions when local water tables were higher and seepage erosion was more effective.

  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. 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. 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.

    2015-01-01

    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.

  5. MANAGING AND RESTORING UPLAND RIPARIAN MEADOWS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    Riparian meadow ecosystems in upland watersheds are of local and regional importance in the Great Basin. Covering only 1-3% of the total land area, these ecosystems contain a disproportionally large percentage of the region's biodiversity. Stream incision, due to natural and anth...

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

    SciTech Connect

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

    1986-03-01

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

  7. GEOMORPHIC AND HYDROGEOLOGICAL CONTROLS ON THE DISTRIBUTION OF WET MEADOWS IN THE CENTRAL GREAT BASIN

    EPA Science Inventory

    The Great Basin is an arid landscape dominated by dryland vegetation such as big sage and xeric grasses. Meadow complexes occur in mountain drainages and consist of discrete parcels of land up to several hectares in area that are characterized by high water tables and that primar...

  8. Geohydrology, Geochemistry, and Ground-Water Simulation-Optimization of the Central and West Coast Basins, Los Angeles County, California

    USGS Publications Warehouse

    Reichard, Eric G.; Land, Michael; Crawford, Steven M.; Johnson, Tyler D.; Everett, Rhett; Kulshan, Trayle V.; Ponti, Daniel J.; Halford, Keith L.; Johnson, Theodore A.; Paybins, Katherine S.; Nishikawa, Tracy

    2003-01-01

    Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers, increased delivery of imported water, and increased use of reclaimed water. In order to improve the scientific basis for these water management activities, an extensive data collection program was undertaken, geohydrological and geochemical analyses were conducted, and ground-water flow simulation and optimization models were developed. In this project, extensive hydraulic, geologic, and chemical data were collected from new multiple-well monitoring sites. On the basis of these data and data compiled and collected from existing wells, the regional geohydrologic framework was characterized. For the purposes of modeling, the three-dimensional aquifer system was divided into four aquifer systems?the Recent, Lakewood, Upper San Pedro, and Lower San Pedro aquifer systems. Most pumpage in the two basins is from the Upper San Pedro aquifer system. Assessment of the three-dimensional geochemical data provides insight into the sources of recharge and the movement and age of ground water in the study area. Major-ion data indicate the chemical character of water containing less than 500 mg/L dissolved solids generally grades from calcium-bicarbonate/sulfate to sodium bicarbonate. Sodium-chloride water, high in dissolved solids, is present in wells near the coast. Stable isotopes of oxygen and hydrogen provide information on sources of recharge to the basin, including imported water and water originating in the San Fernando Valley, San Gabriel Valley, and the coastal plain and surrounding hills. Tritium and carbon-14 data provide information on relative ground-water ages. Water with

  9. 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

  10. Constraints on the pre-extensional paleoelevation of the central Basin and Range from carbonate clumped-isotope paleothermometry

    NASA Astrophysics Data System (ADS)

    Niemi, N. A.; Lechler, A. R.; Hren, M. T.; Lohmann, K. C.

    2011-12-01

    Large-magnitude Cenozoic extension across the Basin and Range has been constrained on the basis of a wide variety of geological and geophysical studies. Despite this regional extension, and associated crustal thinning, the Basin and Range maintains high (>1 km) regional elevations, and a fairly uniform, and typical thickness, continental crust. A number of geodynamic models have been proposed to explain these apparent contradictions, and a potentially useful discriminant between these models are the different predictions each makes for the paleoelevation history of the Basin and Range. We present new carbonate clumped-isotope paleothermometry data that bears on this paleoelevation history. Clumped isotope paleothermometry from lacustrine micrites in two Paleocene sections provides constraints on the paleoelevation of east-central Nevada prior to large-magnitude regional extension and core complex formation in Eocene time. The Goler Formation, which outcrops in the El Paso Mountains, east of the Sierra Nevada, has a known paleoelevation at or near sea-level and yields paleotemperatures on the order of 40°C (Universal Reference Frame (URF) Δ47 = 0.63-0.65). Lacustrine micrites from the age-equivalent Sheep Pass Formation in the Egan Range, Nevada, yield paleotemperatures of ~23-26°C (Δ47 = 0.69-0.71). Using a typical range of terrestrial lapse rates, the temperature difference between these two sites is indicative of a paleoelevation for the Sheep Pass Formation of 2500-3000 m, or perhaps as much as 1000 m higher than the elevation of present-day exposure. In the central Basin and Range, where large-magnitude upper crustal extension is generally well-constrained to have occurred later than 15 Ma, paleotemperatures of two pre-extensional (16-20 Ma) lacustrine micrites in the Death Valley region are ~25-28°C (Δ47 = 0.69-0.70). Lacustrine micrites within the Bena gravel (~17 Ma), exposed in the western Sierra Nevada, and deposited at sea-level on the paleo

  11. Long-term agroecosystem research in the central Mississippi river basin: goodwater creek experimental watershed flow data.

    PubMed

    Baffaut, Claire; Sadler, E John; Ghidey, Fessehaie

    2015-01-01

    Flow monitoring in Goodwater Creek Experimental Watershed started in 1971 at three nested watersheds ranging from 12 to 73 km. Since then, runoff or stream flow has been measured at 14 plots, three fields, and 12 additional stream sites ranging from 0.0034 to 6067 km in the Central Mississippi River Basin. Long-term data sets are important to document the changes resulting from anthropogenic and natural drivers. The data set presented here documents discharge across a range of catchment sizes in an area known for its high runoff potential. It constitutes the flow database of the Central Mississippi River Basin site of the Long-Term Agricultural Research network. Like the other sites of this network, data are accessible through the STEWARDS web interface (). Here we (i) describe the data collection methods, (ii) document the data available at plot, field, and watershed scales, and (iii) provide the main characteristics of discharge. General characteristics of discharge per unit area for different cropping system management systems show that in this claypan soil setting, management and tillage of row crop systems do not affect surface flow during the growing season (April-October). Data from fields and stream sites show the dampening of peak flow values and lengthening of storm hydrographs caused by mixed land uses and longer times of concentration. Overall, stream flow accounts for a third of the precipitation, of which 80% is from surface runoff and 20% is from groundwater. PMID:25602317

  12. New Data on Land Subsidence Phenomena Due to Excessive Ground Water Withdrawal in the Western Thessaly Basin, Central Greece

    NASA Astrophysics Data System (ADS)

    Sideri, D.; Rozos, D.; Loupasakis, C.; Kotsanis, D.

    2012-04-01

    The Western Thessaly basin is a major plain which is located in Central Greece. During the last decades this area exhibits an intensive development, mainly based on the agricultural economy. Due to that agricultural development, several thousand boreholes have been drilled for irrigation purposes. The overexploitation of the ground water, in the wider area, has triggered the manifestation of land subsidence phenomena. These phenomena were firstly observed in 2002 in the Stavros and Farsala sites (southeast part of the Western Thessaly basin), in the form of various surface ruptures. In 2009 similar phenomena appeared in Agios Georgios village and in 2011 in Anohori and Katohori villages, which are located between Farsala and Stavros towns. The geological environment of the research area consists of terrestrial sands and gravels horizons Pleistocene in age, with brown and grey clayey silt to silty clay intercalations. These alternations of permeable coarse-grained deposits (aquifers) with impermeable to low permeability strata (aquitards) create a number of successive semi-confined to confined aquifers, sometimes artesians. Land subsidence deformations were noticed both along the margins as well as in the inner part of the basin. Surface ruptures are observed along the margins of the basin where the bedrock outcrops and generally in areas where the thickness of the Pleistocene deposits appear to be small. On the contrary, in the parts of the basin with thick deposits, the subsidence of the Pleistocene formations can be noticed by the extraction of the water wells pipes. During this research a detailed geotechnical and hydrogeological survey was carried out covering the study area. Several hundreds of boreholes, drilled in the frame of previous geological-geotechnical investigations, were analyzed and interpreted, along with previous data, referring to the stratigraphy of the study area. As a result, the highly compressible units, which may be responsible for

  13. 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.

  14. Nested Calderas in the Northern Kawich Range, Central Nevada: Termination of the Ignimbrite Flare-up in the Great Basin

    NASA Astrophysics Data System (ADS)

    Honn, D. K.; Smith, E. I.

    2006-05-01

    During the ignimbrite flare-up in the Great Basin of the western United States nearly 500,000 km3 of ash- flow tuff related to caldera collapse was erupted between about 40 and 23 Ma. In the central Great Basin the flare-up ended abruptly at about 23 Ma and major caldera generating eruptions did not occur again for nearly 7 Ma. To test models for the demise of this voluminous igneous event, we studied ash-flow tuffs in the northern Kawich Range, central Nevada that erupted just before the end of the ignimbrite flare-up. Five calderas were discovered in the northern Kawich Range; each filled with intracaldera rhyolite tuffs and caldera collapse breccias. Based on 40Ar / 39Ar dating of sanidine and crosscutting relations, the calderas erupted in the following order from oldest to youngest: Clifford Spring (23.67 ± 0.09 Ma), Tobe Spring (22.77 ± 0.07 Ma), Cow Canyon (22.78 ± 0.07 Ma), Bellehelen (22.87 ± 0.16 Ma), and Warm Springs. Field evidence including the occurrence of older welded tuff clasts in younger collapse breccia deposits indicates that these calderas represent separate events and not a single caldera with piecemeal collapse. The five intracaldera tuffs are chemically and chronologically similar to the widespread Pahranagat Formation (33,000 km2)and the Pyramid Spring tuff. To explain the eruption of at least seven tuffs of very similar chemistry over a short period of time (1.06 m.y), large scale partial melting (>50%) of the lower crust is required. Transfer of heat from the crust to the atmosphere during these eruptions cooled the crust may have resulted in the suppression of the ignimbrite flare-up in the Great Basin at 23 Ma.

  15. Early Cenozoic Shortening and Foreland Basin Sedimentation in the Marañon Fold-thrust Belt, Central Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Jackson, L. J.; Carlotto, V.; Horton, B. K.; Rosell, L. N.

    2015-12-01

    The Marañon fold-thrust belt in the westernmost Andes of Peru has long been considered a robust signature of early Cenozoic shortening in the Andean orogenic belt. However, the structural details and potential records of coeval synorogenic sedimentation remain elusive. We report results from new geologic mapping (1:50,000), cross-section construction, and U-Pb geochronology for the Matucana-Ticlio region at 11-12°S along the Lima-La Oroya highway. Zircon U-Pb age data from volcanic rocks and clastic basin fill provide a maximum depositional age of ~43 Ma for a middle Eocene syndeformational unit that we identify as the Anta Formation, which overlies the Paleocene Casapalca Formation. Sedimentary lithofacies and unconformable relationships within the volcaniclastic Anta Formation reveal mixed fluvial, alluvial-fan, and volcanic depositional conditions during shortening accommodated by a NE-verging thrust/reverse fault and corresponding backthrust (here named the Chonta fault system). Our cross-section reconstruction and geochronological data indicate that the region is a critical, possibly unique, zone of the broader NE-directed Marañon fold-thrust belt where pre-Neogene synorogenic sediments and their associated structures are preserved. We interpret this combined structural and basin system as an Eocene-age (Incaic) frontal thrust belt and corresponding foredeep to wedge-top depozone in central Peru. As one of the better-constrained segments of the Marañon fold-thrust belt, this zone provides insight into potential linkages with elusive early Cenozoic (Incaic) structures and foreland basin fill of the Western Cordillera and Altiplano farther south in the central Andean plateau.

  16. Joint inversion of surface wave velocity and gravity observations and its application to central Asian basins shear velocity structure

    NASA Astrophysics Data System (ADS)

    Maceira, Monica; Ammon, Charles J.

    2009-02-01

    We implement and apply a method to the jointly inverted of surface wave group velocities and gravity anomalies observations. Surface wave dispersion measurements are sensitive to seismic shear wave velocities, and the gravity measurements supply constraints on rock density variations. Our goal is to obtain a self-consistent three-dimensional shear velocity-density model with increased resolution of shallow geologic structures. We apply the method to investigate the structure of the crust and upper mantle beneath two large central Asian sedimentary basins: the Tarim and Junggar. The basins have thick sediment sections that produce substantial regional gravity variations (up to several hundred milligals). We used gravity observations extracted from the global gravity model derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. We combine the gravity anomalies with high-resolution surface wave slowness tomographic maps that provide group velocity dispersion values in the period range between 8 and 100 s for a grid of locations across central Asia. To integrate these data, we use a relationship between seismic velocity and density constructed through the combination of two empirical relations. One determined by Nafe and Drake, most appropriate for sedimentary rocks, and a linear Birch's law, more applicable to denser rocks (the basement). An iterative, damped least squares inversion including smoothing is used to jointly model both data sets, using shear velocity variations as the primary model parameters. Results show high upper mantle shear velocities beneath the Tarim basin and suggest differences in lower crust and upper mantle shear velocities between the eastern and western Tarim.

  17. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    SciTech Connect

    Ernest A. Mancini; Donald A. Goddard

    2005-04-15

    The principal research effort for the first six months of Year 2 of the project has been petroleum system characterization. Understanding the burial and thermal maturation histories of the strata in the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas is important in petroleum system characterization. The underburden and overburden rocks in these basins and subbasins are a product of their rift-related geohistory. Petroleum source rock analysis and thermal maturation and hydrocarbon expulsion modeling indicate that an effective regional petroleum source rock in the onshore interior salt basins, the North Louisiana Salt Basin, Mississippi Interior Salt Basin, Manila Subbasin and Conecuh Subbasin, was the Upper Jurassic Smackover lime mudstone. The Upper Cretaceous Tuscaloosa shale was an effective local petroleum source rock in the Mississippi Interior Salt Basin and a possible local source bed in the North Louisiana Salt Basin. Hydrocarbon generation and expulsion was initiated in the Early Cretaceous and continued into the Tertiary in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin. Hydrocarbon generation and expulsion was initiated in the Late Cretaceous and continued into the Tertiary in the Manila Subbasin and Conecuh Subbasin. Reservoir rocks include Jurassic, Cretaceous and Tertiary siliciclastic and carbonate strata. Seal rocks include Jurassic, Cretaceous and Tertiary anhydrite and shale beds. Petroleum traps include structural and combination traps.

  18. Infrastructure development and agricultural exposure to climate variability and change: lessons from the Limarí basin in Central Chile

    NASA Astrophysics Data System (ADS)

    Vicuna, S.; Alvarez, P.; Melo, O.; Dale, L. L.; Meza, F. J.

    2012-12-01

    The Limarí basin, located in Central Chile, is a world famous example of how the development of reservoirs and irrigation infrastructure can reduce climate vulnerabilities allowing the economic development of a basin. Before the infrastructure was developed low value crops such as cereals dominated land use acreage. Today high value crops such as vineyards, orchards and vegetables account for almost 50% of total land and cereals have almost disappear. Key to this evolution have been the reduction in water supply variability, access to international markets, increased irrigation efficiency, and the existence of water markets and other flexible and strong institutions that have helped moving the water from low to high value uses. These factors are related to each other sharing infrastructure development as a common root. The system of reservoirs in the Limarí basin was designed and has been operated since its construction with the premise that droughts in this basin do not last longer than 4 years. Until recently that had been the case and farmers have been able to withstand the impacts of droughts. When faced with water supply reductions farmers would select from a set of options to accommodate their needs including: water market participation, groundwater extraction and crop irrigation and crop acreage decisions. The use of these options has even allowed increasing total irrigated land mostly through the expansion of permanent water demand crops. In the past 9 years however, the basin has experienced a longer than usual drought, interrupting the reservoir refilling cycle that characterized climate variability in the region. This situation has led to dramatically low reservoir levels and continuous reductions in water supply. In addition, due to the already high levels of irrigation efficiency and large amount of acreage devoted to permanent water demand crops, the effectiveness of the portfolio of options available to farmers to accommodate to these stressing

  19. Origin and Development of El Bajío Basin in the Central Sector of Trans-Mexican Volcanic Belt

    NASA Astrophysics Data System (ADS)

    Botero, P. A.; Alaniz Álvarez, S. A.; Nieto Samaniego, Á. F.; Lopez-Martinez, M.; Levresse, G.; Xu, S.; Ortega Obregón, C.

    2015-12-01

    Volcanism of the Trans-Mexican Volcanic Belt has been placed on pre-existing tectonic basins; one of them is El Bajío Basin. We present the origin and evolution of this basin through the study of its deformation events occurring mainly on the El Bajío fault, at the boundary between the Trans-Mexican Volcanic Belt and the Mesa Central. Detailed stratigraphy, and structural analysis suggest 4 deformation events in the northwest of the Sierra de Guanajuato. The first event (D1) with E-W shortening is characterized by the development of axial plane foliation (S1) with N-S direction, this event occurred between the Tithonian and Aptian age. In the second event (D2), occurred between the Albian and the early Eocene, foliations NW-SE (S2) were generated with a NE-SW shortening trend dated between the Albian and early Eocene, this deformation is related to the Laramide Orogeny. The Granito Comanja was emplaced during the third event (D3) and generated foliation (S3) in sediments of the complejo vulcanosedimentario Sierra de Guanajuato that circumscribes the Granito Comanja in response to its intrusion. After its emplacement, NW-SE normal faults were generated along the S-SE contact of the Granito Comanja, at that time El Bajío fault began. The fourth event (D4) has three phases that affected the sedimentary and volcanic Cenozoic rocks. D4F1 is marked by continental conglomerates deposition with variable thickness along of the main trace of the El Bajío fault. D4F2 affected the Oligocene volcanic rocks showing an important fault activity at that time, as evidenced the tilting above 45o in the Oligocene rocks, temporarily coincides with the triaxial extension to the Mesa Central. The direction of elongation of D4F3 is ESE-WNW, El Bajío fault had little movement. Since the Miocene the deformation was concentrated along the southern central sector of the Trans-mexican Volcanic Belt and there were few deformation in the Mesa central. During the three phases of deformation

  20. Multiple Magmatic Events Over 40 Ma in the Fish Creek Mountains, North-central Great Basin, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Cousens, B.; Henry, C. D.; Stevens, C.; Varve, S.

    2011-12-01

    The Fish Creek Mountains, located in north-central Nevada south of Battle Mountain, is a site of multiple igneous events ranging from ca. 35 Ma to 1 Ma, covering most of the igneous history of the Great Basin of the western United States. Such extended volcanic activity allows for documentation of mantle sources and petrogenetic processes over time. Beginning approximately 50 Ma, the Great Basin experienced a magmatic front that began migrating southwestward across southern Idaho, central Oregon and into northern Nevada and Utah. Intermediate, "arc-like" andesite and dacite dominated volcanic activity in northeastern Nevada between about 45 and 36 Ma. By 34 Ma, a northwest-trending belt of rhyolitic ash-flow calderas began to develop through central Nevada, the "ignimbrite flare-up". Volcanism then migrated westwards towards the Sierra Nevada. In north-central Nevada, the oldest lavas are ca. 35 Ma basaltic andesites through rhyolites that are exposed in the western Shoshone Range, the eastern Tobin Range, and the northern and eastern Fish Creek Mountains. Plagioclase-rich andesites, dacite intrusions, and volcanic breccias occur in a belt along the western side of the Fish Creek Mountains. The bulk of the Fish Creek Mountains is composed of the 24.7 Ma Fish Creek Mountains rhyolitic tuff that is largely confined to an undeformed caldera structure. The caldera and tuff are anomalously young compared to nearby felsic centers such as the Caetano caldera (33.8Ma) and Shoshone Range (39-35 Ma) and relative to the southwest to west magmatic migration. The basal tuff is unwelded, with abundant pumice and lithic (primarily volcanic) fragments but only rare crystals. Sanidine and smoky quartz phenocrysts become more abundant upsection and glassy fiamme (hydrated to devitrified) are common, but the abundance of lithic fragments diminishes. 16-15 Ma volcanic rocks of the Northern Nevada Rift are exposed in the Battle Mountain area, ranging in composition from subalkaine

  1. Assessment of selected inorganic constituents in streams in the Central Arizona Basins Study Area, Arizona and northern Mexico, through 1998

    USGS Publications Warehouse

    Anning, David W.

    2003-01-01

    Stream properties and water-chemistry constituent concentrations from data collected by the National Water-Quality Assessment and other U.S. Geological Survey water-quality programs were analyzed to (1) assess water quality, (2) determine natural and human factors affecting water quality, and (3) compute stream loads for the surface-water resources in the Central Arizona Basins study area. Stream temperature, pH, dissolved-oxygen concentration and percent saturation, and dissolved-solids, suspended-sediment, and nutrient concentration data collected at 41 stream-water quality monitoring stations through water year 1998 were used in this assessment. Water-quality standards applicable to the stream properties and water-chemistry constituent concentration data for the stations investigated in this study generally were met, although there were some exceedences. In a few samples from the White River, the Black River, and the Salt River below Stewart Mountain Dam, the pH in reaches designated as a domestic drinking water source was higher than the State of Arizona standard. More than half of the samples from the Salt River below Stewart Mountain Dam and almost all of the samples from the stations on the Central Arizona Project Canal?two of the three most important surface-water sources used for drinking water in the Central Arizona Basins study area?exceeded the U.S. Environmental Protection Agency drinking water Secondary Maximum Contaminant Level for dissolved solids. Two reach-specific standards for nutrients established by the State of Arizona were exceeded many times: (1) the annual mean concentration of total phosphorus was exceeded during several years at stations on the main stems of the Salt and Verde Rivers, and (2) the annual mean concentration of total nitrogen was exceeded during several years at the Salt River near Roosevelt and at the Salt River below Stewart Mountain Dam. Stream properties and water-chemistry constituent concentrations were related to

  2. Aptian depositional patterns influenced by salt tectonics, central east Texas basin

    SciTech Connect

    Lomando, A.J.; Birdsall, T.P.

    1989-03-01

    Salt tectonics, which lead both directly and indirectly to the formation of paleobathymetric highs, peripheral sinks and persistent structural highs, strongly influenced carbonate and siliciclastic depositional patterns of the Aptian Rodessa Formation. This study has focused on northern Anderson County, located in the axial portion of what was the broad, shallow East Texas basin shelf during deposition of the Rodessa. Five Louann (Bathonian-Callovian) Salt diapirs were active and had significant impact on Aptian depositional patterns.

  3. Petrographic and Facies Properties of the Evaporites in the Cihanbeyli-Yeniceoba Basin (Central Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Sami Us, Muhammed; Tekin, Erdoǧan

    2016-04-01

    The Cihanbeyli-Yeniceoba Tertiary basin and other neighbouring basins such as Haymana on the NW and Tuzgölü on the east were formed after ophiolite emplacement and then evolved as tectonic controlled basins bordered with normal and oblique-slip fault systems NW-SE in extending. Where sedimentation commenced with Late Cretaceous-Early Paleocene marine transgression and ended by late Middle Eocene-Early Oligocene regression that involved thick evaporite sedimentation just before the onset of the terrestrial regime through the early Late Oligocene-Pliocene time. This study mainly was focused on the evaporitic sediments of the Late Oligocene-Middle Miocene aged Gökdaǧ Formation which unconformably overlain by fluvial and alluvial units of the Cihanbeyli Formation (Late Miocene-Early Pliocene). Typical outcrops have been seen around the Yeniceoba-Kütükuşaǧı-Kuşca region located in the western part of Tuz Gölü (Salt Lake). The study includes several targets. These are stratigraphical contact and relationship between evaporite and non-evaporite units, evaporite environments and mineralogical, petrographical and microtextural features of the evaporites. The following five evaporite facies were described: a) massive gypsum (F1), b) laminated-banded gypsum (F2), c) nodular gypsum (F3), d) clastic gypsum (F4), e) satin-spar gypsum (F5). On the other hand polarized microscope and scanning electron microscope (SEM) show that secondary gypsums are represented by alabastrine and porfiroblastic textures. Primary anhydrite relicts, euhedral celestine crystals accompanied with the secondary gypsum. Clastic gypsum is rich in fragment fossils (mostly nummulites) and kaolinite clay minerals. All data suggest that evaporites were widely deposited as basin margin evaporite that temporally underwent atmospheric conditions gave rise to detrital gypsum ranging from gypsarenite to gypsum conglomerate. Acknowledgement:This presentation was prepared MS thesis to financially

  4. Devonian shales of central Appalachian basin: geological controls on gas production

    SciTech Connect

    Lowry, P.H.; Hamilton-Smith, T.; Peterson, R.M. )

    1989-03-01

    Gas reserves of the Devonian shales of the Appalachian basin constitute a large, underdeveloped resource producing from fractured reservoirs. As part of ongoing Gas Research Institute research, K and A Energy Consultants, Inc., is identifying geological controls on gas production. Preliminary findings indicate that local gas production is controlled by a combination of structure and stratigraphy. Regional geological review indicates that Devonian sedimentation and structure is influenced by repeated reactivation of basement faults. Site-specific geologic studies indicate that depositional and structural mechanisms vary substantially throughout the basin. Gas production on the eastern margin of the producing area is controlled by an Alleghenian thrust front located by Grenville normal faults. High-capacity wells are associated with tear faults in the thrust sheets. To the southwest, deformation is controlled by both Grenville and Rome trough basement faults. Reactivation of these faults during later orogenic events produced a complex of high-angle reverse and strike-slip faults. Fracturing in the Devonian shales is produced by shearing and flexure associated with these structures. Syndepositional movement of the basement structures influenced the deposition of coarser grained turbidites and tempestites. The combination of fractures and coarser clastic beds provides effective reservoir systems. The shale contains abundant organic material consisting of terrestrial plant debris and marine algal remains. Thermal maturation of this material produced gas which charged the lower reservoir systems. Exploration along reactivated structural trends is an effective strategy for locating Devonian shale gas accumulations. This approach may also apply to other producing strata in the basin.

  5. Synextensional basin evolution, lower Miocene Clews Formation, central Mojave Desert, California

    SciTech Connect

    Fillmore, R.P.; Walker, J.D. )

    1991-02-01

    The lower Miocene Clews Formation at Alvord Mountain, Mojave Desert, California, consists of up to 400 m of coarsening-upward continental deposits. During the initial stage of basin development, the depocenter was delineated by a lacustrine system that was bound to the west by alluvial fans and graded northward into a south-flowing fluvial braidplain. Lacustrine strata, composed of claystone, siltstone and carbonate, suggest an initially closed basin. Conglomerate and sandstone to the west represent small, sheetflood-dominated fans and contain igneous clasts and southeasterly paleoflow indicative of a proximal, relatively low relief source in the western Alvord Mountains. The second stage of deposition was dominated by coarse conglomerate and megabreccia with west-southwesterly paleotransport indicators and a distinctive metaigneous petrofacies that indicate a provenance in the Cronese Hills, 8 km to the east. These strata reflect rapid westward progradation of debris flow-dominated alluvial fans that advanced across the facia braidplain, eventually onlapping the smaller Alvord Mountain sourced fans across the basin. Influx of sediment from the paradise Range ceased. Based development resulted from regional northeast-southwest extensional deformation. The Alvord Mountain-Cronese Hills region was transported northeast as a single block on an east-dipping, low-angle normal fault associated with the Waterman Hills core complex 30 km to the west. Development of westward prograding fans is believed to record subsequence propagation of a northwest-trending, west-dipping normal fault associated with, but antithetic to the low-angle master fault.

  6. Hydrogeologic Framework and Ground Water in Basin-Fill Deposits of the Diamond Valley Flow System, Central Nevada

    USGS Publications Warehouse

    Tumbusch, Mary L.; Plume, Russell W.

    2006-01-01

    The Diamond Valley flow system, an area of about 3,120 square miles in central Nevada, consists of five hydrographic areas: Monitor, Antelope, Kobeh, and Diamond Valleys and Stevens Basin. Although these five areas are in a remote part of Nevada, local government officials and citizens are concerned that the water resources of the flow system eventually could be further developed for irrigation or mining purposes or potentially for municipal use outside the study area. In order to better understand the flow system, the U.S. Geological Survey in cooperation with Eureka, Lander, and Nye Counties and the Nevada Division of Water Resources, is conducting a multi-phase study of the flow system. The principal aquifers of the Diamond Valley flow system are in basin-fill deposits that occupy structural basins comprised of carbonate rocks, siliciclastic sedimentary rocks, igneous intrusive rocks, and volcanic rocks. Carbonate rocks also function as aquifers, but their extent and interconnections with basin-fill aquifers are poorly understood. Ground-water flow in southern Monitor Valley is from the valley margins toward the valley axis and then northward to a large area of discharge by evapotranspiration (ET) that is formed south of a group of unnamed hills near the center of the valley. Ground-water flow from northern Monitor Valley, Antelope Valley, and northern and western parts of Kobeh Valley converges to an area of ground-water discharge by ET in central and eastern Kobeh Valley. Prior to irrigation development in the 1960s, ground-water flow in Diamond Valley was from valley margins toward the valley axis and then northward to a large discharge area at the north end of the valley. Stevens Basin is a small upland basin with internal drainage and is not connected with other parts of the flow system. After 40 years of irrigation pumping, a large area of ground-water decline has developed in southern Diamond Valley around the irrigated area. In this part of Diamond

  7. Oblique fault systems crossing the Seattle Basin: Geophysical evidence for additional shallow fault systems in the central Puget Lowland

    NASA Astrophysics Data System (ADS)

    Mace, Chris G.; Keranen, Katie M.

    2012-03-01

    Upper plate seismicity in the Puget Lowland is more broadly distributed than mapped fault systems and presents a conundrum for understanding the active tectonics of the region. Although many previous studies have mapped faulting in the Puget Lowland from subsurface geophysical data, many of these efforts have focused specifically on mapping the structure of the Seattle Fault Zone and the South Whidbey Island Fault. The thick glacial sediments and extensive water bodies may conceal additional active faults away from these major structures. We map fault networks in Quaternary sediments broadly throughout the central Puget Lowland using existing marine multichannel seismic reflection data sets with widely distributed profiles to extend the results of previous work. We identify a NE-SW zone of recent high-angle faulting and shallow sediment deformation crossing the Seattle Uplift and the Seattle Basin that segments the Seattle Fault Zone and is distinct from previously mapped fault systems. Faults in this zone cut or deform sediments at the seafloor, and the zone trends across the central Puget Lowland at an oblique angle to major regional structures. Two additional zones of faulting trend NW-SE and cut through the Seattle Basin and the Kingston Arch, respectively. Aeromagnetic lineations extend the NE-SW trend of deformation across the Seattle Uplift and connect deformation of shallow sediment in the Puget Sound with deformation of shallow sediment in the Hood Canal. These oblique fault structures may partially control the wide distribution of seismicity within the central Puget Lowland and should be considered in seismic hazard assessments.

  8. Evapotranspiration from the Lower Walker River Basin, West-Central Nevada, Water Years 2005-07

    USGS Publications Warehouse

    Allander, Kip K.; Smith, J. LaRue; Johnson, Michael J.

    2009-01-01

    Evapotranspiration is the ultimate path of outflow of nearly all water from the Lower Walker River basin. Walker Lake is the terminus of the topographically closed Walker River basin, and the lake level has been declining at an average rate of about 1.6 feet per year (ft/yr) since 1917. As a result of the declining lake level, dissolved-solids concentrations are increasingly threatening the fishery and ecosystem health of the lake. Uncertainties in the water budget components of the Lower Walker River basin led the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, to undertake an investigation to refine estimates of the water budget. Evapotranspiration from the Lower Walker River basin represents a major component of this water budget. The specific objectives of this report are to provide estimates of total and net evapotranspiration for water years 2005-07 for areas in the Lower Walker River basin in which annual evapotranspiration exceeds annual precipitation, and to summarize these results for areas of similar vegetation and soil characteristics, hydrographic subareas, and Walker Lake and Weber Reservoir. The three hydrographic subareas include the area along Walker River north of Walker Lake, the area of and adjacent to Walker Lake, and the area south of Walker Lake. Areas of annual evapotranspiration exceeding annual precipitation were identified and mapped in the field and were further delineated using remote-sensing analysis. These areas were classified into 10 evapotranspiration units. A network of 11 evapotranspiration stations was operated in natural and agricultural vegetation and on Walker Lake. Measured evapotranspiration rates ranged from 0.5 ft/yr at a sparsely vegetated desert shrub site to 5.0 ft/yr from Walker Lake. The greatest evapotranspiration rate on land was 4.1 ft/yr at an irrigated alfalfa field, and the greatest rate for natural vegetation was 3.9 ft/yr in a riparian community along Walker River. At an

  9. The segmentations and the significances of the Central Canyon System in the Qiongdongnan Basin, northern South China Sea

    NASA Astrophysics Data System (ADS)

    Su, Ming; Xie, Xinong; Xie, Yuhong; Wang, Zhenfeng; Zhang, Cheng; Jiang, Tao; He, Yunlong

    2014-01-01

    The submarine canyons as the important element of the source to sink have attracted the widespread interests in studying their morphologic features, stratigraphic frames, depositional architectures, as well as the related depositional model, hydrodynamic simulation, and hydrocarbon exploration. The Central Canyon System, a large axial submarine canyon, in the Qiongdongnan Basin is developed in Neogene passive continental margin of northern South China Sea, which is paralleled to the shelf break with an "S-shaped" geometry and an NE-NEE orientation. Based on the integrated analysis of high-resolution 2D/3D seismic data and well log data, the whole canyon could be divided into three segments from west to east through its distinct morphological and depositional architecture characteristics, the head area, the western segment and the eastern segment. The canyon shows the classical U-shaped morphology in seismic profiles, and the infillings are composed of a suit of turbidite channel complex in the head area. In the western segment, the canyon demonstrates the sinuous geometry and multiple-shaped morphology in seismic profiles. Four complexes of turbidite channel and mass transport complex (MTC) are observed, which could constitute into two stratigraphic cycles. The canyon in the eastern segment shows V-shaped morphology with steep flanks and a narrow and straight course, which is composed of collapse deposits in the flanks and the sheet sand-MTC complex. The sediment supply, northern continental slope system, paleo-geomorphic characteristics and tectonic setting in the Qiongdongnan Basin are considered as the controlling factors on the development and evolution of the Central Canyon System, each of them have different influences in the three segments. The turbidite channel in the head area was triggered by the abundant sediment supply from western source together with the fault activity at 5.7 Ma of the Red River Fault. The evolution of the canyon in the western

  10. Gravity data of the Norcia and Castelluccio basins (central Italy): insight for active faulting of the area

    NASA Astrophysics Data System (ADS)

    Ruano, P.; Rustichelli, A.; Galindo-Zaldívar, J.; Piccardi, L.; Ruiz-Constán, A.; Tondi, E.; López-Garrido, A. C.; Sanz de Galdeano, C.

    2009-04-01

    The Norcia and Castelluccio basins are located in the central Apennines, the southeastern extension of the NE-vergent arcuate, Neogene, foreland fold and thrust belt of northern Italy. These intramontane depressions are infilled by Pleistocene-Holocene coarse continental fluvial and alluvial deposits, whereas the bedrock units are represented by limestone and pelagic marls of Jurassic to Miocene age. Several historical and instrumental highly destructive earthquakes have occurred in this area: January 14, 1703 (X MCS, M=6.6); September 19, 1979 (Ms= 5.9, focal depth of 6-8km). Fault data and earthquake focal mechanisms show a predominant NE-SW extension, but strike-slip and even reverse mechanisms have also been determined. The surface of the Norcia basin is flat, slightly inclined to the NW, with only an almost isolated basement hill in the middle. The basin has a predominant NNW-SSE elongation with very straight boundaries constituted by oblique-extensional faults. In addition, Castelluccio Depression is a hanging basin located eastwards of the Norcia area. In order to determine the distribution of the sedimentary infill, a gravity survey has been developed in the region, including several profiles orthogonal to the basin edges and additional scattered data that improve the map coverage. Measurements have been done in the basins and also in the basement in order to determine the regional anomalies. A Scintrex CG-5 gravitimeter with an accuracy of 0.001mGal, a barometric altimeter of 0.5 m of precision, and a Garmin e-trex GPS have been used during the acquisition of the 294 measurements. A density of 2.60 g/cm3 (mean density of the basement limestone) has been considered for calculating the Bouguer Anomalies. Terrain corrections have been determined using the SRTM90-m. The Foligno absolute gravity base station has been taking into account during this survey. The Bouguer Anomaly is negative in all the area, with a regional trend that decreases northeastwards

  11. Persistent toxic substances in soils and waters along an altitudinal gradient in the Laja River Basin, Central Southern Chile.

    PubMed

    Barra, Ricardo; Popp, Peter; Quiroz, Roberto; Bauer, Coretta; Cid, Hernan; von Tümpling, Wolf

    2005-02-01

    In this study the levels and distribution of some persistent toxic substances (PTS) were investigated in soils, superficial water, and snow along an altitudinal gradient in the Laja River Basin (South Central Chile). The principal objective was to establish the basin's contamination status. The working hypothesis was that PTS levels and distribution in the basin are dependent on the degree of anthropogenic intervention. Fifteen PAHs, seven PCBs congeners, and three organochlorine pesticides were studied in superficial soil and water samples obtained along the altitudinal gradient and from a coastal reference station (Lleu-Lleu River). Soil samples were extracted using accelerated solvent extraction with acetone/cyclohexane (1:1) for PAHs and organochlorine compounds. Contaminants were extracted from water and snow samples by liquid-liquid extraction (LLE). PAH and organochlorine compound quantification was carried out by HPLC with fluorescence detection and GC-MS, respectively. PCBs in soils presented four different profiles in the altitudinal gradient, mainly determined by their chlorination degree; these profiles were not observed for the chlorinated pesticides. In general, the detected levels for the analyzed compounds were low for soils when compared with soil data from other remote areas of the world. Higher summation operator PAHs levels in soils were found in the station located at 227 masl (4243 ng g-1 TOC), in a forestry area and near a timber industry, where detected levels were up to eight times higher than the other sampling sites. In general, PAH levels and distribution seems to be dependent on local conditions. No pesticides were detected in surface waters. However, congeners of PCBs were detected in almost all sampling stations with the highest levels being found in Laja Lake waters, where 1.1 ng/l were observed. This concentration is two times higher than values reported for polluted lakes in the Northern Hemisphere. The presence of organochlorine

  12. Hydrologic and water-quality conditions in the Horse Creek Basin, west-central Florida, October 1992-February 1995

    USGS Publications Warehouse

    Lewelling, B.R.

    1997-01-01

    A baseline study of the 241-square-mile Horse Creek basin was undertaken from October 1992 to February 1995 to assess the hydrologic and water-quality conditions of one of the last remaining undeveloped basins in west-central Florida. During the period of the study, much of the basin remained in a natural state, except for limited areas of cattle and citrus production and phosphate mining. Rainfall in 1993 and 1994 in the Horse Creek basin was 8 and 31 percent, respectively, above the 30-year long-term average. The lowest and highest maximum instantaneous peak discharge of the six daily discharge stations occurred at the Buzzard Roost Branch and the Horse Creek near Arcadia stations with 185 to 4,180 cubic feet per second, respectively. The Horse Creek near Arcadia station had the lowest number of no-flow days with zero days and the Brushy Creek station had the highest number with 113 days. During the study, the West Fork Horse Creek subbasin had the highest daily mean discharge per square mile with 30.6 cubic feet per second per square mile, and the largest runoff coefficient of 43.7 percent. The Buzzard Roost Branch subbasin had the lowest daily mean discharge per square mile with 5.05 cubic feet per second per square mile, and Brushy Creek and Brandy Branch shared the lowest runoff coefficient of 0.6 percent. Brandy Branch had the highest monthly mean runoff in both 1993 and 1994 with 11.48 and 19.28 inches, respectively. During the high-baseflow seepage run, seepage gains were 8.87 cubic feet per second along the 43-mile Horse Creek channel. However, during the low-baseflow seepage run, seepage losses were 0.88 cubic foot per second. Three methods were used to estimate average annual ground-water recharge in the Horse Creek basin: (1) well hydrograph, (2) chloride mass balance, and (3) streamflow hydrograph. Estimated average annual recharge using these three methods ranged from 3.6 to 8.7 inches. The high percentage of carbonate plus bicarbonate analyzed at

  13. Timing and duration of the Central Atlantic magmatic province in the Newark and Culpeper basins, eastern U.S.A.

    NASA Astrophysics Data System (ADS)

    Marzoli, Andrea; Jourdan, Fred; Puffer, John H.; Cuppone, Tiberio; Tanner, Lawrence H.; Weems, Robert E.; Bertrand, Hervé; Cirilli, Simonetta; Bellieni, Giuliano; De Min, Angelo

    2011-03-01

    New major and trace element data and 40Ar/ 39Ar plateau ages constrain the timing, duration and time-related geochemical evolution of the Central Atlantic magmatic province in the U.S.A. (Newark and Culpeper basins) and refine correlations with basaltic lava flows from other Late Triassic-Early Jurassic circum-Atlantic basins. The precise, statistically robust 40Ar/ 39Ar plateau ages were obtained on biotite and on fresh plagioclase and calculated using the latest 40K decay constants. These ages are supported by a general consistency of the Ca/K calculated from 37Ar/ 39Ar of the plateau steps and the Ca/K obtained by detailed electron microprobe analyses on plagioclase phenocrysts. The ages of five analyzed basalt lava flows, from all three lava flow units in the Newark basins, and the ages of two sill samples are indistinguishable, indicating a brief magmatic peak phase at 201.8 ± 0.7 Ma. Recalibrated 40Ar/ 39Ar plateau ages from the entire province indicate a near-synchronous onset and peak volcanic activity at the Triassic-Jurassic boundary within the circum-Atlantic basins from the U.S.A., Canada and Morocco. The early erupted magmas (Moroccan Lower to Upper basalts, the Fundy basin North Mountain Basalt, and Orange Mountain and equivalent U.S.A. flows) yield an enriched geochemical signature (e.g., with relatively high La/Yb), whereas late magmas in the U.S.A. (Hook Mountain and Hampden basalts) and Morocco (Recurrent basalt) yield relatively depleted geochemical compositions (low La/Yb). A slight, but significant age difference for eruption of Hook Mountain and Hampden basalts (200.3 ± 0.9 Ma) and Recurrent basalts (198.2 ± 1.1 Ma) is interpreted as evidence of a diachronous northward rift-drift transition during break-up of Pangea. Our data indicate also a prolonged intrusive sequence that continued until about 195 Ma at the Palisades sill and is consistent with sporadic late CAMP magmatism for dykes from the south-eastern U.S.A. and for intrusions from

  14. The complex 3-D transition from continental crust to backarc magmatism and exhumed mantle in the Central Tyrrhenian basin

    NASA Astrophysics Data System (ADS)

    Prada, M.; Sallares, V.; Ranero, C. R.; Vendrell, M. G.; Grevemeyer, I.; Zitellini, N.; de Franco, R.

    2015-10-01

    Geophysical data from the MEDOC experiment across the Northern Tyrrhenian backarc basin has mapped a failed rift during backarc extension of cratonic Variscan lithosphere. In contrast, data across the Central Tyrrhenian have revealed the presence of magmatic accretion followed by mantle exhumation after continental breakup. Here we analyse the MEDOC transect E-F, which extends from Sardinia to the Campania margin at 40.5°N, to define the distribution of geological domains in the transition from the complex Central Tyrrhenian to the extended continental crust of the Northern Tyrrhenian. The crust and uppermost mantle structure along this ˜400-km-long transect have been investigated based on wide-angle seismic data, gravity modelling and multichannel seismic reflection imaging. The P-wave tomographic model together with a P-wave-velocity-derived density model and the multichannel seismic images reveal seven different domains along this transect, in contrast to the simpler structure to the south and north. The stretched continental crust under Sardinia margin abuts the magmatic crust of Cornaglia Terrace, where accretion likely occurred during backarc extension. Eastwards, around Secchi seamount, a second segment of thinned continental crust (7-8 km) is observed. Two short segments of magmatically modified continental crust are separated by the ˜5-km-wide segment of the Vavilov basin possibly made of exhumed mantle rocks. The eastern segment of the 40.5°N transect E-F is characterized by continental crust extending from mainland Italy towards the Campania margin. Ground truthing and prior geophysical information obtained north and south of transect E-F was integrated in this study to map the spatial distribution of basement domains in the Central Tyrrhenian basin. The northward transition of crustal domains depicts a complex 3-D structure represented by abrupt spatial changes of magmatic and non-magmatic crustal domains. These observations imply rapid variations

  15. Long-term hydro-climatic changes in the Selenga river basin, Central Asia

    NASA Astrophysics Data System (ADS)

    Törnqvist, Rebecka; Asokan, Shilpa M.; Pietroń, Jan; Jarsjö, Jerker; Destouni, Georgia

    2014-05-01

    Climatic changes can lead to altered hydrological conditions, which in turn can impact pollutant loading patterns to the terminal recipient of a considered basin. Lake Baikal is the deepest and largest freshwater reservoir on Earth. The lake and its surroundings have been declared an UNESCO World Heritage Site due to its unique ecosystem with numerous endemic animal and plant species. The Selenga river basin, which is located in northern Mongolia and southern Siberia in Russia, is the largest sub-basin of the Lake Baikal. Mining is well developed in the region and has been identified to be the main pollution source for the water system in the sparsely populated region. We investigate long-term historic and projected future hydro-climatic conditions in the Selenga river basin with the aim to improve the understanding of such underlying conditions in the basin. This understanding is fundamental for preventing degradation of Lake Baikal's unique ecosystem from for instance mining activities. Specifically, our objective is to identify observed historical hydro-climatic changes during the 72-year period of 1938-2009. In addition, we assess multi-model ensemble means of the Coupled Model Intercomparison Project, Phase 5 (CMIP5) in order to also consider future projections of hydro-climatic changes for a near future period (2010-2039) and a more distant future period (2070-2099). The results show that there has been an observed increase in mean annual temperature in the basin by about 1.5°C during the period 1938-2009. Moreover, a longer seasonal period of temperatures above zero (especially due to increasing spring temperatures) is detected. For the annual water balance components of precipitation, evapotranspiration and runoff, relatively small temporal changes are observed. However, in recent years there has been a detected decrease in runoff, with 10-year running averages reaching their lowest levels within the whole investigation period. In particular, there has

  16. Resource Assessment of the In-Place and Potentially Recoverable Deep Natural Gas Resource of the Onshore Interior Salt Basins, North Central and Northeastern Gulf of Mexico

    SciTech Connect

    Ernest A. Mancini; Paul Aharon; Donald A. Goddard; Roger Barnaby

    2005-10-28

    The principal research effort for Year 2 of the project has been petroleum system characterization and modeling. Understanding the burial, thermal maturation, and hydrocarbon expulsion histories of the strata in the onshore interior salt basins of the North Central and Northeastern Gulf of Mexico areas is important in hydrocarbon resource assessment. The underburden and overburden rocks in these basins and subbasins are a product of their rift-related geohistory. Petroleum source rock analysis and initial thermal maturation and hydrocarbon expulsion modeling indicated that an effective regional petroleum source rock in the onshore interior salt basins and subbasins, the North Louisiana Salt Basin, Mississippi Interior Salt Basin, Manila Subbasin and Conecuh Subbasin, was Upper Jurassic Smackover lime mudstone. The initial modeling also indicated that hydrocarbon generation and expulsion were initiated in the Early Cretaceous and continued into the Tertiary in the North Louisiana Salt Basin and the Mississippi Interior Salt Basin and that hydrocarbon generation and expulsion were initiated in the Late Cretaceous and continued into the Tertiary in the Manila Subbasin and Conecuh Subbasin. Refined thermal maturation and hydrocarbon expulsion modeling and additional petroleum source rock analysis have confirmed that the major source rock in the onshore interior salt basins and subbasins is Upper Jurassic Smackover lime mudstone. Hydrocarbon generation and expulsion were initiated in the Early to Late Cretaceous and continued into the Tertiary.

  17. Latest Permian to Middle Triassic cyclo-magnetostratigraphy from the Central European Basin, Germany: Implications for the geomagnetic polarity timescale

    NASA Astrophysics Data System (ADS)

    Szurlies, Michael

    2007-09-01

    In Central Germany, the about 1 km thick mainly clastic Germanic Lower Triassic (Buntsandstein) consists of about 60 sedimentary cycles, which are considered to reflect variability in precipitation within the epicontinental Central European Basin, most probably due to solar-induced short eccentricity cycles. They provide a high-resolution cyclostratigraphic framework that constitutes the base for creating a composite geomagnetic polarity record, in which this paper presents a Middle Buntsandstein to lowermost Muschelkalk magnetostratigraphy obtained from 6 outcrops and 2 wells where a total of 471 samples was collected. Combined with recently established records, a well-documented magnetostratigraphy for the upper Zechstein to lowermost Muschelkalk (latest Permian to Middle Triassic) of Central Germany has been constructed, encompassing an overall stratigraphic thickness of about 1.3 km and 22 magnetozones derived from about 2050 paleomagnetic samples. Along with available biostratigraphy, this multi-disciplinary study facilitates detailed links to the marine realm, in order to directly refer biostratigraphically calibrated Triassic stage boundaries as well as radioisotopic ages to the Buntsandstein cyclostratigraphy and, conversely, to contribute to calibrating the geologic timescale.

  18. Stratigraphic framework of Cambrian and Ordovician rocks across Rome Trough, central Appalachian basin

    SciTech Connect

    Ryder, R.T.

    1987-09-01

    Restored stratigraphic cross sections drawn primarily through the subsurface of parts of Pennsylvania, Ohio, West Virginia, Kentucky, and Tennessee provide new detailed information to further the understanding of Cambrian and Ordovician sedimentation and tectonics associated with the Rome trough sector of the Appalachian basin. Drilled thickness of the Cambrian and Ordovician sequence ranges from a maximum of about 14,500 ft (4.5 km) along the axis of the trough to a minimum of about 3500 ft (1 km) on the western flank.

  19. A glaciological baseline for the upper Olivares basin, Chilean Central Andes

    NASA Astrophysics Data System (ADS)

    Loriaux, T.; Bown, F.; Burger, F.; Cisternas, S.; Gacitúa, G.; Hernández, J.; Malmros, J.; Muñoz, C.; Oberreuter, J.; Rivera, A.; Silva, R.

    2013-12-01

    Santiago de Chile, with near 6.7 million of inhabitants, is located at the foot of the Andes, in the Maipo river basin, where there are approximately 424 km2 of ice, being the biggest glaciers, those located at the upper Olivares basin. Very little has been researched in recent years about the ongoing changes taking place in the area or about the glacier meltwater contribution or about the human impact on the glaciers. In order to tackle this deficiency, we began a research program in 2012, aiming to complete a glaciological baseline for this area, including glacier mass, energy and hydrological studies. For this purpose, we have established a detailed monitoring program on two glaciers where we installed 3 automatic weather stations, two arrays of stakes for mass balance studies, two automatic photographic cameras for monitoring albedo changes and two runoff stations, among several other instruments. Also, we have surveyed 5 glaciers with our airborne radar and lidar systems, allowing mapping their surface topographies at different seasons and the bedrocks underneath the ice. Analysis of satellite images shows generalized glacier area shrinkage, with a mean area lost of 25.5% since 1967 (total of 68.6 km2 in 1967 among 6 studied glaciers). The collected radar ice thickness data (maximum ice thickness of 223 m), allowed calculating a total volume of water equivalent of 3 km3 storage in 5 main glaciers of the basin. The GPS surveys of several stakes resulted in surface ice velocities between 1 and 5 m/yr. The mass balance studies showed high summer ablation rates, with an important role of sublimation, expressed as penitentes with heights of up to 1.5 m. Runoff contributed by Olivares Alfa glacier averaged 461 l/s between January and April 2013 with peaks of up to 2000 l/s, confirming the importance of glacier meltwater for the basin during summer months (January-March). The above numbers are some of the results obtained in the area, illustrating the importance of

  20. Palaeo-altimetry of the late Eocene to Miocene Lunpola basin, central Tibet.

    PubMed

    Rowley, David B; Currie, Brian S

    2006-02-01

    The elevation history of the Tibetan plateau provides direct insight into the tectonic processes associated with continent-continent collisions. Here we present oxygen-isotope-based estimates of the palaeo-altimetry of late Eocene and younger deposits of the Lunpola basin in the centre of the plateau, which indicate that the surface of Tibet has been at an elevation of more than 4 kilometres for at least the past 35 million years. We conclude that crustal, but not mantle, thickening models, combined with plate-kinematic solutions of India-Asia convergence, are compatible with palaeo-elevation estimates across the Tibetan plateau. PMID:16467830

  1. Hydrology of the Wolf Branch sinkhole basin, Lake County, east-central Florida

    USGS Publications Warehouse

    Schiffer, D.M.

    1996-01-01

    A 4-year study of the hydrology of the Wolf Branch sinkhole basin in Lake County, Florida, was conducted from 1991-95 by the U.S. Geological Survey to provide information about the hydrologic characteristics of the drainage basin in the vicinity of Wolf Sink. Wolf Branch drains a 4.94 square mile area and directly recharges the Upper Floridan aquifer through Wolf Sink. Because of the direct connection of the sinkhole with the aquifer, a contaminant spill in the basin could pose a threat to the aquifer. The Wolf Branch drainage basin varies in hydrologic characteristics from its headwaters to its terminus at Wolf Sink. Ground- water seepage provides baseflow to the stream north of Wolf Branch Road, but the stream south of State Road 46 is intermittent and the stream can remain dry for months. A single culvert under a railroad crossing conducts flow from wetlands just south of State Road 46 to a well-defined channel which leads to Wolf Sink. The basin morphology is characterized by karst terrain, with many closed depressions which can provide intermittent surface-water storage. Wetlands in the lower third of the basin (south of State Road 46) also provide surface water storage. The presence of numerous water-control structures (impoundments, canals, and culverts), and the surface-water storage capacity throughout the basin affects the flow characteristics of Wolf Branch. Streamflow records for two stations (one above and one below major wetlands in the basin) indicate the flow about State Road 46 is characterized by rapid runoff and continuous baseflow, whereas below State Road 46, peak discharges are much lower but of longer duration than at the upstream station. Rainfall, discharge, ground-water level, and surface-water level data were collected at selected sites in the basin. Hydrologic conditions during the study ranged from long dry periods when there was no inflow to Wolf Sink, to very wet periods, as when nearly 7 inches of rain fell in a 2-day period in

  2. 1982 Environmental monitoring report, Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Millard, G.C.; Gray, C.E.; Simmons, T.N.; O'Neal, B.L.

    1983-04-01

    Because radionuclides are potentially released from its research activities, SNL has a continuing environmental monitoring program which analyzes for cesium-137, tritium, uranium, alpha emitter, and beta emitters in water, soil, air, and vegetation. Measured radiation levels in public areas were consistent with local background in 1982. The Albuquerque population received an estimated 0.170 person-rem from airborne radioactive releases, whereas it received greater than 50,400 person-rem from naturally occurring radionuclides.

  3. Deposition of selenium and other constituents in reservoir bottom sediment of the Solomon River Basin, north-central Kansas

    USGS Publications Warehouse

    Christensen, Victoria G.

    1999-01-01

    The Solomon River drains approximately 6,840 square miles of mainly agricultural land in north-central Kansas. The Bureau of Reclamation, U.S. Department of the Interior, has begun a Resource Management Assessment (RMA) of the Solomon River Basin to provide the necessary data for National Environmental Policy Act (NEPA) compliance before renewal of long-term water-service contracts with irrigation districts in the basin. In May 1998, the U.S. Geological Survey (USGS) collected bottom-sediment cores from Kirwin and Webster Reservoirs, which are not affected by Bureau irrigation, and Waconda Lake, which receives water from both Bureau and non-Bureau irrigated lands. The cores were analyzed for selected physical properties, total recoverable metals, nutrients, cesium-137, and total organic carbon. Spearman's rho correlations and Kendall's tau trend tests were done for sediment concentrations in cores from each reservoir. Selenium, arsenic, and strontium were the only constituents that showed an increasing trend in concentrations for core samples from more than one reservoir. Concentrations and trends for these three constituents were compared to information on historical irrigation to determine any causal effect. Increases in selenium, arsenic, and strontium concentrations can not be completely explained by Bureau irrigation. However, mean selenium, arsenic, and strontium concentrations in sediment from all three reservoirs may be related to total irrigated acres (Bureau and non-Bureau irrigation) in the basin. Selenium, arsenic, and strontium loads were calculated for Webster Reservoir to determine if annual loads deposited in the reservoir were increasing along with constituent concentrations. Background selenium, arsenic, and strontium loads in Webster Reservoir are significantly larger than post-background loads.

  4. Application of microtremor array measurements to delineate S-wave velocity structures in Bangkok Basin, central Thailand

    NASA Astrophysics Data System (ADS)

    Hayashi, K.; Pananont, P.; Wongpanit, T.; Habangkham, S.

    2014-12-01

    The Bangkok Basin, located in the lower part of the Chao Phraya River Basin in central Thailand contains very thick sediment and are often affected by the large distant earthquakes due to local site amplification. Shear wave velocities (Vs) measurements have been performed at five sites in the Bangkok Basin (Figure 1) by a two-station spatial autocorrelation method (2ST-SPAC) using long-period accelerometers. Receiver separation varied from 5 to 2,100m and maximum separation (array size) varied from 1,800 to 2,100 m. In each separation, 10 to 90 minutes ambient noise was recorded with sampling interval of 10 ms. Due to the security concern, data acquisition was performed in the day-time and in relatively quiet places such as in parks or less densely residential areas. A spatial autocorrelation was used for calculating phase velocity and clear dispersion curves were obtained in frequency range from about 0.3 to 10 Hz. Minimum frequency and corresponding maximum wavelength ranged from 0.32 to 0.48 Hz and about 2,180 to 5,140 m, depending on the site. An inversion consisting of a least squares method and a Genetic Algorithm was used to estimate Vs profiles from the dispersion curves to a depth of about 1,000 to 2,500 m depending on the sites. Figure 2 shows comparison of Vs profiles obtained by the inversion. We can see that a low velocity layer with Vs lower than 400 m/s exists between depths of 0 to 200 m at all sites. Intermediate bedrock with Vs higher than 1,000 m/s exists between depths of 240 to 1,250 m. Deepest bedrock with Vs higher than 2,000 m/s seems to exist at a depth of at least 1,600 m.

  5. The non-transform discontinuity on the Central Indian Ridge at 11°S: The transtensional basin formation and hydrothermal activity

    NASA Astrophysics Data System (ADS)

    Pak, S. J.; Kim, H. S.; Son, J.; Kim, J.; Moon, J. W.; Son, S. K.

    2014-12-01

    The bathymetric and magnetic survey, hydrocasting and seabed sampling have been carried out in the middle portion of the Central Indian Ridge (MCIR) between 7°S and 17°S. The MCIR constitutes six first-order segments and seven second-order segments with four non-transform discontinuities (NTDs) and twelve ocean core complexes (OCCs). These segments are characterized by asymmetric accretion that corresponds to about 70% of the surveyed MCIR segment. One of the outstanding NTD in the area is a basin like NTD3-1 at 11°S (50km in length) which strike at 035°, approximately 45° oblique in a clockwise direction to the orientation of two adjoining second-order segments. The hydrothermal activity is recognized at the tips of NTD3-1. No abyssal hills paralleling to basin-shape NTD3-1 are observed. Anomalous depth of the basin, lack of positive magnetic anomaly across the basin and rare seismic activities in the basin floor suggests that extensional tectonism with a sparse volcanism is the dominant process occurring along the NTD3-1. Based on the previous researches that the counterclockwise rotation of ridge is predominant in the area, the region of NTD3-1 largely accommodates shear strain by left-lateral sense motion and consequently forms a transtensional basin, i.e., a pull-apart basin. The strong and frequent hydrothermal plume signals, and highly tectonized rocks in both tips of the NTD3-1 are reflective of the dilation zones or tensional fractures accompanied by the pull-apart basin formation. It is the first identification of a pull-apart basin associated with hydrothermal activity in the Central Indian Ridge.

  6. Introduction to selected references on fossil fuels of the central and southern Appalachian basin: Chapter H.1 in Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character

    USGS Publications Warehouse

    Ruppert, Leslie F.; Lentz, Erika E.; Tewalt, Susan J.; Román Colón, Yomayra A.

    2014-01-01

    The Appalachian basin contains abundant coal and petroleum resources that have been studied and extracted for at least 150 years. In this volume, U.S. Geological Survey (USGS) scientists describe the geologic framework and geochemical character of the fossil-fuel resources of the central and southern Appalachian basin. Separate subchapters (some previously published) contain geologic cross sections; seismic profiles; burial history models; assessments of Carboniferous coalbed methane and Devonian shale gas; distribution information for oil, gas, and coal fields; data on the geochemistry of natural gas and oil; and the fossil-fuel production history of the basin. Although each chapter and subchapter includes references cited, many historical or other important references on Appalachian basin and global fossil-fuel science were omitted because they were not directly applicable to the chapters.

  7. Application of thematic mapper imagery to oil exploration in Austin Chalk, central Gulf Coast basin, Texas

    SciTech Connect

    Reid, W.M.

    1988-02-01

    One of the newest major oil plays in the Gulf Coast basin, the Austin Chalk reportedly produces in three belts: an updip belt, where production is from fractured chalk in structurally high positions along faults above 7000 ft; a shallow downdip belt, where the chalk is uniformly saturated with oil from 7000 to 9000 ft; and a deeper downdip belt saturated with gas and condensate below 9000 ft. The updip fields usually occur on the southeastern, upthrown side of the Luling, Mexia, and Charlotte fault zones. Production is from fractures that connect the relatively sparse matrix pores with more permeable fracture systems. The fractures resulted from regional extensional stress during the opening of the Gulf Coast basin on the divergent margin of the North American plate during the Laramide orogeny. The fractures are more common in the more brittle chalk than in the overlying Navarro and underlying Eagle Ford shales, which are less brittle. The oil in the updip traps in the chalk may have been generated in place downdip, and migrated updip along the extension fractures into the updip traps during or after the Laramide orogeny. A fairway of previously unmapped updip faults and drag folds has been mapped using Thematic Mapper imagery and seismic, structural, and resistivity maps near the Nixon field, Burleson County, Texas. This fairway, prospective for oil from the Austin Chalk, contains wells reported to produce from the Austin Chalk which lie along lineaments and linear features on the Thematic Mapper imagery and faults in the seismic and structure maps.

  8. Post-glacial paleoenvironments of the Lake Winnebago basin, east central Wisconsin, based on ostracodes

    SciTech Connect

    Fielder, R.F.; Smith, G.L.; Fitzgerald, T.M. . Dept. of Geology)

    1994-04-01

    Ostracodes were used to determine post-glacial paleoenvironments of the Lake Winnebago Basin. Following the retreat of the Wisconsinian Green Bay Lobe, Glacial Lake Oshkosh was dammed behind the ice sheet. As the modern Fox River was established, Glacial Lake Oshkosh shrank to form modern Lake Winnebago. Ostracodes were sampled from four vibracores in attempts to correlate sedimentary units and determine paleoenvironments. The oldest unit identified in their vibracores is grayish red clay that is thought to be reworked glacial till that was deposited in a lacustrine setting. This clay is dominated by Candona rawsoni, an ostracod species that prefers cold and deep water. The broken and eroded carapaces of the C. rawsoni in the greyish-red clay suggest reworking and transport, perhaps from the Lake Superior Basin. The contact between the clay and overlying sediments is an erosional unconformity, overlain in some places by gravel. The clay is overlain by coarsening-upward from sandy-silt to medium-grained sand, suggesting a decrease in lake levels and water depths. Raised shorelines 20 and 60 ft above present lake level constitute the geomorphic evidence for higher lake levels. Offshore, at depths of ten to twenty feet, the sediment type above is an olive black organic-rich mud where juveniles of C. rawsoni are the dominant species.

  9. Oolitic and pisolitic ironstones in the early Ordovician (Arenig) of the Amadeus Basin, central Australia

    NASA Astrophysics Data System (ADS)

    Gorter, John D.

    Early Ordovician oolitic ironstone was first reported from the subsurface Pacoota Sandstone of the Amadeus Basin in the Tempe Vale 1 petroleum exploration well in 1982, and found subsequently in Tent Hill 1 and Mt Winter 2 coreholes. Density log correlations and descriptions of cuttings show the presence of ironstones in other wells in the northwestern part of the basin. Several measured sections in the same general area also contain discrete beds of oolitic or pisolitic ironstone. All known occurrences are in the Early Arenig upper Pacoota Sandstone. Two types of deposition are apparent: Type 1 oolitic ironstones gradationally overlie a shallowing-upward marine clastic cycle, commencing with deeper water shales and passing upward through bioturbated siltstones to cross-bedded sandstones, and terminating in bioturbated oolitic ironstones; and Type 2 oolitic ironstones are invariably sharply bounded, non-bioturbated, generally structureless but sometimes cross-bedded, occur interbedded with marine clastics, and do not always occur at the top of shallowing-upward cycles. Type 1 oolithic ironstones are interpreted to have been deposited in-situ upon shoaling barrier bars in a low energy, shallow intracratonic sea. Type 2 ironstones are interpreted to have been reworked from the tops of such barrier bars, possibly during storms, and redeposited in offshore to lower shoreface environments.

  10. Application of thematic mapper imagery to oil exploration in Austin Chalk, Central Gulf Coast basin, Texas

    SciTech Connect

    Reid, W.M.

    1988-01-01

    One of the newest major oil plays in the Gulf Coast basin, the Austin Chalk reportedly produces in three belts: an updip belt, where production is from fractured chalk in structurally high positions along faults above 7,000 ft; a shallow downdip belt, where the chalk is uniformly saturated with oil from 7,000 to 9,000 ft; and a deeper downdip belt saturated with gas and condensate below 9,000 ft. The updip fields usually occur on the southeastern, upthrown side of the Luling, Mexia, and Charlotte fault zones. Production is from fractures that connect the relatively sparse matrix pores with more permeable fracture systems. The fractures resulted from regional extensional stress during the opening of the Gulf Coast basin on the divergent margin of the North American plate during the Laramide orogeny. The fractures are more common in the more brittle chalk than in the overlying Navarro and underlying Eagle Ford shales, which are less brittle. The oil in the updip traps in the chalk may have been generated in place downdip, and migrated updip along the extension fractures into the updip traps during or after the Laramide orogeny.

  11. 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.

  12. Floods of December 1982 to May 1983 in the central and southern Mississippi River and the Gulf of Mexico basins

    USGS Publications Warehouse

    Stone, Roy B.; Bingham, Roy H.

    1991-01-01

    Widespread flooding occurred in December 1982 and in spring 1983 in the central and southern Mississippi River basin. The first series of storms, December 2-7, caused severe flooding along many streams in Illinois, Missouri, and Arkansas. Much of the three-State area experienced recordbreaking 24-hour rainfall amounts that caused some streams to exceed previously known flood heights and discharges; in many cases the recurrence interval of peak discharges exceeded 100 years. The second series of storms, December 24-29, caused severe flooding in Louisiana and moderate flooding in Mississippi. Peak discharges on some streams exceeded the 100-year recurrence interval. Damages exceeded $200 million and 25 persons died as a result of the December storms. Western Tennessee was on the fringes of both storms and received only minor flooding. During April 4-8, 1983, as much as 17 inches of rain fell in parts of southern Mississippi and southeastern Louisiana. In some areas, 24-hour amounts exceeded 5 inches, causing peak discharges to exceed the recurrence interval of 100 years at 20 streamflow gaging stations. In May 1983 heavy and intense rains caused major flooding in the Big Black River and Pearl River basins in Mississippi.

  13. Decadal to millennial-scale solar forcing of Last Glacial Maximum climate in the Estancia Basin of central New Mexico

    NASA Astrophysics Data System (ADS)

    Menking, Kirsten M.

    2015-05-01

    Lacustrine sediments from the Estancia Basin of central New Mexico reveal decadal to millennial oscillations in the volume of Lake Estancia during Last Glacial Maximum (LGM) time. LGM sediments consist of authigenic carbonates, detrital clastics delivered to the lake in stream flow pulses, and evaporites that precipitated in mudflats exposed during lake lowstands and were subsequently blown into the lake. Variations in sediment mineralogy thus reflect changes in hydrologic balance and were quantified using Rietveld analysis of X-ray diffraction traces. Radiocarbon dates on ostracode valve calcite allowed the construction of mineralogical time series for the interval ~ 23,600 to ~ 18,300 ka, which were subjected to spectral analysis using REDFIT (Schulz and Mudelsee, 2002). Dominant periods of ~ 900, ~ 375, and ~ 265 yr are similar to cycles in Holocene 14C production reported for a variety of tree ring records, suggesting that the Lake Estancia sediments record variations in solar activity during LGM time. A prominent spectral peak with a period of ~ 88 yr appears to reflect the solar Gleissberg cycle and may help, along with the ~ 265 yr cycle, to explain an ongoing mystery about how Lake Estancia was able to undergo abrupt expansions without overflowing its drainage basin.

  14. 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.

  15. 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.

  16. Western Central Asia - Uzbekistan:new insights into the basin architecture and lithosphere structures from geophysical data

    NASA Astrophysics Data System (ADS)

    Sidorova, Irina

    2014-05-01

    This report was prepared as one part of joint Uzbekistan's Working Group results by DARIUS programme, provided in Uzbekistan during the 2009-2013 years. The special attention is devoted to potential geophysical fields and results of interpretation of seismic profiles, which was the base for conclusions about deep lithosphere structure of the DARIUS domains in Uzbekistan.For four last years 12 field expeditions in Uzbekistan were organized by the DARIUS projects - were studied new geological sections and now the new ideas developing about geodynamical evolution in Western Central Asia. The state of art reveals a very heterogeneous set of data. These data commonly deal either with particular basins or mountain belts, or specific basin investigations. Our aim was to combine all available seismic, magnetic and geothermal data with the revealed of the tectonically objects, geological structures, and to show their interrelated temporal and spatial development for general understanding of the inner structure of lithosphere and upper layers of Earth's crust. In link of this, the detailed studying structure of Paleozoic crystal basement on representative basic sites and the crossing faults, accompained by drawing up of level-by-level and summary sections, large-scale geological and geophysical mapping was conducted. Our study elucidated the lithosphere-scale processes driving forces for kinematic of blocks between southern Tien Shan and Pamir. All our data were integrated in the DARIUS database GEOLIS.

  17. Characterization of a small-scale drainage basin in Central Portugal - a multidisciplinary approach

    NASA Astrophysics Data System (ADS)

    Correia, Carla G.; Azevedo, José Manuel; Rodrigues, Nelson V.; Figueiredo, Fernando P. O.

    2015-04-01

    This study presents a multidisciplinary characterization of a small-scale watershed encompassing its topography, geology, local and regional tectonics, morphometry of the drainage system, soil type, land use and climatology. All this parameters are important controllers of the groundwater circulation and storage, as well as the localization of the recharge areas. It also identifies the piezometric changes, the upper (or phreatic) aquifer flow and the major recharge areas. Simultaneously, it includes the hydrochemical classification and the active hydrogeochemical processes occurring on the local aquifers. The combined analysis of these data is necessary for interpreting the hydrodynamics of the local aquifer units. The research focused on the surrounding domains of Olhos da Fervença spring, particularly in the Fervença watershed, a small-scale drainage basin close to Cantanhede city (Coimbra District, Portugal). This watershed is located on a rural area within the Vouga hydrographic basin. The methodology included: (1) delimitation of the watershed; (2) geometric (or physiographic) characterization of the basin; (3) analysis of the digital elevation model to quantify the slopes and to detect structural alignments that influence the surface and groundwater flow; (4) geologic characterization of the basin; (5) description of the soil type and the land use; (6) classification of the regional climatic conditions; (7) inventory and regular hydrogeologic characterization of wells (diameter, depth, wellhead and piezometry); (8) elaboration of piezometric maps in order to identify the groundwater flow; (9) groundwater sampling and in situ measurement of physico-chemical parameters (pH, groundwater temperature, specific electrical conductivity, Eh, dissolved oxygen, HCO3); (10) conducting laboratorial hydrochemical analyzes (Cl, NO3, SO4, PO4, Ca, Na, Mg, K, Fe, Mn, Al); (11) groundwater classification, hydrochemical interpretation and identification of the water

  18. Porphyry copper assessment of Central America and the Caribbean Basin: Chapter I in Global mineral resource assessment

    USGS Publications Warehouse

    Gray, Floyd; Hammarstrom, Jane M.; Ludington, Stephen; Zürcher, Lukas; Nelson, Carl E.; Robinson, Gilpin R., Jr.; Miller, Robert J.; Moring, Barry C.

    2014-01-01

    This assessment estimated a total mean of 37 undiscovered porphyry copper deposits within the assessed permissive tracts in Central America and the Caribbean Basin. This represents more than five times the seven known deposits. Predicted mean (arithmetic) resources that could be associated with these undiscovered deposits are about 130 million metric tons of copper and about 5,200 metric tons of gold, as well as byproduct molybdenum and silver. The reported identified resources for the seven known deposits total about 39 million metric tons of copper and about 930 metric tons of gold. The assessment area is estimated to contain nearly four times as much copper and six times as much gold in undiscovered porphyry copper deposits as has been identified to date.

  19. The northern and central Appalachian basin coal region -- The Upper Freeport and Pond Creek coal bed assessments

    SciTech Connect

    Ruppert, L.; Tewalt, S.; Bragg, L.; Wallack, R.; Freeman, P.; Tully, J.

    1999-07-01

    The Upper Freeport and Pond Creek coal beds are two of six coal beds being assessed by the US Geological Survey (USGS) in the northern and central Appalachian basin coal region. The coal resource assessments were designed to provide up-to-date, concise data on the location, quantity, and quality of US coals for Federal agencies, the public, industry and academia. Assessment products are fully digital and include original and remaining resource estimates; maps depicting areal extent, mined areas, geologic structure contour, isopach, overburden thickness, ash yield, sulfur content, calorific value, and selected trace-element contents; and public domain geochemical and stratigraphic databases. The assessment methodology and a few results are presented.

  20. Long-term agroecosystem research in the central Mississippi river basin: goodwater creek experimental watershed weather data.

    PubMed

    Sadler, E John; Sudduth, Kenneth A; Drummond, Scott T; Vories, Earl D; Guinan, Patrick E

    2015-01-01

    Knowledge of weather, particularly precipitation, is fundamental to interpreting watershed and hydrologic processes. The long-term weather record in the Goodwater Creek Experimental Watershed (GCEW) complements hydrologic and water quality data in the region. The GCEW also is the core of the Central Mississippi River Basin (CMRB) node of the Long-Term Agroecosystem Research network. Our objectives are to (i) describe the climatological context of the GCEW and CMRB settings, (ii) document instrumentation and the data collection, quality assurance, and reduction processes; (iii) provide examples of the data obtained and descriptive statistics; and (iv) document the availability of and access methods to obtain the data from the web-based data access portal at . These objectives support an overall goal to make these long-term data available to the public for use in further analyses and modeling in support of research and public policy on watershed management. PMID:25602316

  1. Geochemistry of Central Atlantic Magmatic Province (CAMP) sills from deep boreholes in the Amazonas and Solimões basins, Brazil

    NASA Astrophysics Data System (ADS)

    Hatlen Heimdal, Thea; Svensen, Henrik H.; Pereira, Egberto; Planke, Sverre

    2016-04-01

    The Central Atlantic Magmatic Province (CAMP) is one of the most extensive Large Igneous Provinces (LIPs), and is associated with the breakup of Pangea and the subsequent opening of the central Atlantic Ocean. A large part of the province, including > 1 M km2 basins containing sill intrusions, is located in Brazil but has received limited attention due to the lack of outcrops. We have studied CAMP sills from seven deep boreholes (up to 3100 m deep) in the Amazonas and Solimões basins, northern Brazil. The boreholes contain up to ~ 482 m of sills (18 % of the stratigraphy), with a maximum individual sill thickness of 140 m. The sills were partly emplaced into thick Carboniferous evaporites. The main mineral phases of the sills include plagioclase and pyroxene, with accessory apatite, biotite, ilmenite and quartz. The majority of the sills are low-Ti dolerites (TiO2 < 2 wt.%), with the exception of four samples (with 2.2 - 3.3 wt.% TiO2). The low-Ti rocks range from basalt to basaltic andesite and plot in the tholeiitic field defined within the total alkali versus silica (TAS) classification. C1 chondrite normalized Rare Earth Element (REE) patterns for both Ti-groups show increasing LREE compared to HREE (La/Lu = 2.2 - 4.1) with no major anomalies, and attest to a relatively evolved nature (La = 17-65 ppm). Primitive mantle normalized patterns for low-Ti rocks show negative anomalies for Nb, Ta, P and Ti and positive for K, whereas the high-Ti rocks show generally opposite anomalies. Late stage patches in the dolerites contain apatite, quartz and Cl-bearing biotite, suggesting the presence of halogens that may partly derive from the host sedimentary rocks.

  2. Spatial and temporal habitat partitioning by zooplankton in the Bornholm Basin (central Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Schulz, Jan; Peck, Myron A.; Barz, Kristina; Schmidt, Jörn Oliver; Hansen, Frank C.; Peters, Janna; Renz, Jasmin; Dickmann, Miriam; Mohrholz, Volker; Dutz, Jörg; Hirche, Hans-Jürgen

    2012-12-01

    The deep basins in the Baltic Sea such as the Bornholm Basin (BB) are subject to seasonal changes in the strength of physico-chemical stratification. These depth-related changes in key abiotic factors are strong drivers of habitat partitioning by the autochthonous zooplankton community. Species-specific ecophysiological preferences often result in both seasonal and inter-annual changes in vertical abundance that, when combined with depth-specific water currents, also lead to horizontal differences in spatial distribution. The present study documented the seasonal and depth-specific changes in the abundance and species composition of zooplankton in the BB based upon broad-scale survey data: 832 vertically-resolved (10 m) multinet samples collected at nine stations between March 2002 and May 2003. Changes in the zooplankton community were significantly correlated with changes in ambient hydrography. Each of five taxa (Bosmina coregoni maritima, Acartia spp., Pseudocalanus spp., Temora longicornis, Synchaeta spp.) contributed >10% to the zooplankton community composition. The appearance of cladocerans was mainly correlated with the phenology of thermocline development in the spring. The cladoceran B. coregoni maritima was a dominant member of this community during the warmest periods, preferring the surface waters above the thermocline. Copepods exhibited distinct, ontogenetic and seasonal changes in their distribution. The rotifers (Synchaeta sp.) were the most abundant zooplankton in May. Based on a multivariate approach and the evaluation of vertical distribution patterns, five major habitat utilisation modes were identified that were based, to a large extent, on the dynamics of thermal and haline stratification of the Baltic Sea. Our statistical analysis of one of the most thorough datasets collected on Baltic zooplankton in recent decades reveals some of the factors that make this stratified system highly dynamic with respect to the spatial overlap between

  3. Post-Panafrican late Proterozoic basins in the Central Anti-Atlas (Morocco): their influence on the Variscan contractional structures.

    NASA Astrophysics Data System (ADS)

    Guimerà, Joan; Arboleya, María. Luisa

    2010-05-01

    Located South of the High Atlas, in Morocco, The Anti-Atlas is a 700 km-long chain trending NE-SW. In the Central Anti-Atlas region, between Warzazat and Taznakht, the Proterozoic Pan-African basement (X1 to X2-3) crops out in isolated areas (boutonnières), where it is overlaid by late to post Pan-African Upper Proterozoic and Palaeozoic rocks. Late to post Pan-African Upper Proterozoic rocks (X3) have been classically divided into three units (X3i, X3m and X3s) which include volcanic rocks — mainly rhyolites— and continental siliciclastic rocks, the older units intruded by late granites (Choubert, 1952 and Choubert et al., 1970). Rocks belonging to the upper unit of post Pan-African Upper Proterozoic rocks (X3s) were deposited in basins bounded by faults with a dominant dip-slip normal motion; as a result, this unit have a variable thickness, being locally absent in the uplifted blocks. Uppermost Proterozoic (Adoudounian) and Palaeozoic rocks deposited unconformable on the older rocks in the Anti-Atlas. The Central Anti-Atlas was slightly deformed during the Variscan orogeny by folds and high-angle thrusts. Two areas are selected to study the post Pan-African to Variscan evolution of the area: the Tiwiyyine basin and the Anti-Atlas Major Fault. Tiwiyyine basin This basin is delimited by kilometric-scale normal faults. Three of them can be observed in the field: two striking NE-SW (NW and SE boundaries) and one striking NW-SE (SW boundary), while the NE boundary is covered by Cenozoic rocks. The basin fill reaches 725 m and has been divided into three units: 1. X3s1: Coarse conglomerates with basal breccias. 2. X3s2: Laminated dolomites at the base, red pelites and conglomerates. 3. X3s3: Conglomerates with interbedded andesites. Unit X3s2 passes laterally to the SW to unit X3s1. The thickness of the basin fill diminishes to the SE. This is specially visible at the basal X3s1 unit. At both sides of the two NE-SW-striking faults, only the upper X3s3 unit is

  4. Sedimentary geochemistry depicts 2700 years of regional climate and land use change in the Rieti Basin, Central Italy

    NASA Astrophysics Data System (ADS)

    Archer, C.; Noble, P. J.; Mensing, S. A.; Tunno, I.; Sagnotti, L.; Florindo, F.; Cifnani, G.; Zimmerman, S. R. H.; Piovesan, G.

    2014-12-01

    A 14.4 m thick sedimentary sequence was recovered in multiple cores from Lago Lungo in the Rieti Basin, an intrapenninic extensional basin ~80 km north of Rome, Italy. This sequence provides a high-resolution record of environmental change related to climatic influence and anthropogenic landscape alteration. Pollen analyses, corroborated with historical records of land-use change, define the major shifts in forest composition and their historical context. An age model of the sequence was built using ties to regional cultigen datums and archaeomagnetic reference curves. Here we focus on sedimentologic and geochemical data (scanning XRF) from the Roman Period through the Little Ice Age (LIA). The base of the sequence (ca. 680 BCE- 1 CE) is marked by a steady increase in fine-grained detrital elements Ti, Rb, and K, and corresponding decrease in Ca, representing a transition from the unaltered system after the Romans constructed a channel that the basin. The Medieval Period (MP; 900-1350 CE) is lithologically distinct, composed of varicolored bands of alternating silt, clay, and calcareous concretions. Low counts of Ca, high detrital elements and frequent abrupt peaks in levels of the redox elements Fe and Mn indicate episodic clastic influx. Pollen data indicate that the greatest degree of deforestation and erosion occurred during the MP, supported by mean sedimentation rates of ca. 1cm/year, over twice the rate of the underlying interval. The Medieval climate was warmer and more stable, population increased, and elevations >1000 m were exploited for agriculture. The influence of the Velino River on the lake appears to increase during the MP through channel migration, increased flooding, or increased overland flow. The next transition (1350 CE) marks the start of the LIA and is coincident with the Black Plague. Historical records document a large earthquake in 1349 that severely struck Central Italy, with possible effects on the lake's depositional and hydrochemical

  5. Heat flow and thermotectonic problems of the central Ventura Basin, southern California

    USGS Publications Warehouse

    De Rito, R. F.; Lachenbruch, A.H.; Moses, T.H., Jr.; Munroe, R.J.

    1989-01-01

    The Ventura Basin, southern California, is located near the Big Bend area of the San Andreas fault system, within the Transverse Ranges physiographic province. Negative curvature of the Ventura Avenue temperature profiles may be explained by an increase in thermal conductivity associated with tectonic compaction of the underlying Pliocene clastic sequence. Basinwide, heat flow averages about 48 mW/m2, a value which is low relative to most of southern California. As heat flow does not vary systematically to the maximum measured depth of about 4 km, this anomly is not easily explained in terms of hydrologic effects or recent uplift and erosion. However, a diminution of heat flow is an expectable consequence of the accumulation of cold sediments (up to 12 km) since Eocene time. -from Authors

  6. Alkaline Basalts of The Quaternary Buffalo Valley Volcanic Field, NW Fish Creek Mountains, North-central Nevada, Great Basin

    NASA Astrophysics Data System (ADS)

    Cousens, B.; Henry, C. D.

    2008-12-01

    The Buffalo Valley volcanic field, 5 km southwest of Battle Mountain, consists of approximately 11 cinder cones and associated flows. Youthful volcanoes are rare in the region, and thus this field offers the opportunity to investigate mantle sources currently beneath the central Great Basin. Most of the eruptive centers are distributed along the northwestern margin of the Fish Creek Mountains, a mid-Tertiary caldera complex, along a 13-km-long northeasterly trend that is perpendicular to the regional stress field (or GPS velocity field), suggesting fault control or eruption from a now-buried fissure. The cones are geomorphologically youthful, with well-defined, commonly breached craters. At least one cone, situated slightly east of the main trend, consists of only a thin mantle of scoria and bombs overlying grey Paleozoic limestone. Previous K-Ar and Ar-Ar dating indicate that the cones are between 1.29 and 0.95 Ma in age. Two other nearby Quaternary volcanic centers lie northeast of the Fish Creek Mountains (K-Ar date of 3.3 Ma) and in the center of the Fish Creek caldera (age unknown). Rare Tertiary basalts and more common Tertiary andesites lie around the margin of the caldera. Lavas from the Buffalo Valley cones have vesicular flow tops and more massive interiors. All Quaternary centers are similar petrographically, including 1-2% olivine phenocrysts and megacrysts up to 1 cm in size, and characteristic plagioclase megacrysts that are rarely up to 4 cm long, commonly in a glassy matrix. Two cone samples are alkalic basalt and tephrite with Mg numbers of 0.55, high TiO2 (2.4%), K2O (2.0%), light REE, Nb (60 ppm), but low Cr and Ni (80 ppm), Pb (2 ppm), Ba (450 ppm) and 87Sr/86Sr (0.70375) compared to Late Pliocene/Quaternary volcanic rocks from the western Great Basin near Reno/Carson City/Fallon. The Buffalo Valley cones are similar chemically to lavas from the Pliocene-Quaternary Lunar Craters volcanic field in central Nevada, and are melts of mantle that is

  7. Origin of middle Silurian Keefer sandstone, east-central Appalachian basin

    SciTech Connect

    Meyer, S.C.; Textoris, D.A.; Dennison, J.M.

    1988-08-01

    The Keefer Sandstone of northeastern West Virginia and western Maryland was deposited in back-barrier, barrier-island, and marine shelf environments along a prograding, storm-dominated, mesotidal coastline of probable low wave energy. Back-barrier sediments were deposited in tidal-flat and lagoonal environments. Barrier-island sediments are dominated by cross-bedded sandstones deposited in deep, laterally migrating tidal inlets. Erosion accompanying the passage of a migrating tidal inlet usually resulted in the removal of underyling shoreface and shelf sands, so that tidal-inlet sandstones commonly lie with a markedly erosive contact on subtidal shales of the underlying Rose Hill Formation. Sand was transported to the shelf from the coastline by downwelling, storm-generated currents. Chamosite ooids formed in gently agitated waters immediately below fair-weather wave base. Outcrops to the east, which preserve back-barrier and barrier-island lithofacies, record a single basinward progradation of the shoreline. However, outcrops farther west, which preserve finer grained sandstone, shale, and limestone shelf lithofacies, document four progradational events in stacked coarsening-upward sequences. Each is typically capped by transgressive sandstones, commonly hematite ooid-bearing, which mark episodes of coastal retreat. Retreat occurred through shoreface and nearshore erosion. Chamosite ooids were transported basinward during coastal retreat and altered to hematite prior to burial. Transgressive shelf sands contain abundant coarse sand eroded from tidal-inlet deposits. Deposition of the Keefer was a response to a decrease in rate of eustatic sea level rise, or a decrease in basin subsidence rate. This was followed by deposition of the transgressive basin facies of the Rochester Shale.

  8. Uranium in spring water and bryophytes at basin creek in central idaho

    USGS Publications Warehouse

    Shacklette, H.T.; Erdman, J.A.

    1982-01-01

    Arkosic sandstones and conglomerates of Tertiary age beneath the Challis Volcanics of Eocene age at Basin Creek, 10 km northeast of Stanley, Idaho, contain uranium-bearing vitrainized carbon fragments. The economic potential of these sandstones and conglomerates is currently being assessed. Springs abound at the contacts of rock units, and water from these springs supports abundant growths of bryophytes (mosses and liverworts). Water from 22 springs and associated bryophytes were sampled; two springs were found to contain apparently anomalous concentrations (normalized) of uranium - as much as 6.5 ??g/L (ppb) in water and 1800 ??g/g (ppm) in ash of mosses. Moss samples from both springs also contained anomalous concentrations of arsenic, and one contained highly anomalous amounts of beryllium. Water from a third spring contained slightly anomalous amounts of uranium, and two species of mosses at the spring contained anomalous uranium (400 and 700 ??g/g) and high levels of both cadmium and lead. Water from a fourth spring was normal for uranium (0.18 ??g/L), but the moss from the water contained a moderate uranium level and highly anomalous concentrations of lead, germanium, and thallium. These results suggest that, in the Basin Creek area, moss sampling at springs may give a more reliable indication of uranium occurrence than would water sampling. The reason for this may be the ability of mosses to concentrate uranium and its associated pathfinder elements and to integrate uranium fluctuations that occur in the spring water over any period of time. ?? 1982.

  9. Mid-Cretaceous unconformity in the Methow basin, north-central Washington

    SciTech Connect

    Haugerud, R.A.; Hurlow, H.A. ); Tabor, R.W. ); Snee, L.W. )

    1993-04-01

    New mapping in the Methow basin demonstrates a significant unconformity beneath mid-Cretaceous strata of the Pasayten Group and may explain stratigraphic contrasts puzzling to earlier workers. The Pasayten Group, defined along regional strike to the north in Manning Park, includes Virginia Ridge Fm. (shallow-marine argillite and chert-clast-rich sandstone and conglomerate), Winthrop Sandstone (fluvial arkose), and Midnight Peak Fm. (redbeds and andesitic volcanic rocks) in ascending stratigraphic order. Local unconformities and lateral gradations amongst Pasayten Group units result in no one unit lying above the unconformity. Hornblende from Midnight Peak andesite on Isabella Ridge yields an [sup 40]Ar-[sup 39]Ar age of 87.0 [+-] 0.4 (1[sigma]) Ma, though Pasayten Group strata elsewhere are intruded by 88--90 Ma plutons and thus much of the unit is older. From west to east the Pasayten Group lies on progressively older strata. In upper Three Fools Creek, west of the Cascade crest, it lies on unnamed marine strata, more than 1 km thick, which conformably overlie 3 km of sand-rich turbidites of the Albian Harts Pass Fm. In the Osceola Peak-Harts Pass area it lies on upper Harts Pass turbidites. Southwest of Monument 85 and west of Hidden Lakes it lies on probable Early Cretaceous (pre-Harts Pass-age) lithic marine sandstone and siltstone. On Isabella Ridge it lies on [approximately]150 Ma tonalite and older volcanic rocks. This unconformity predates most of the conspicuous thrusts and related folds that characterize the Methow basin. Adjacent to the Pasayten fault, pre- and intra-Pasayten Group unconformities have reduced the stratigraphic section to scraps of Winthrop Sandstone and probable lower Cretaceous conglomerate locally preserved between Midnight Peak andesite and older volcanic rocks, suggesting continued early and mid-Cretaceous movement along the Pasayten fault.

  10. Export of dissolved organic carbon from the Penobscot River basin in north-central Maine

    USGS Publications Warehouse

    Huntington, Thomas G.; Aiken, George R.

    2013-01-01

    Dissolved organic carbon (DOC) flux from the Penobscot River and its major tributaries in Maine was determined using continuous discharge measurements, discrete water sampling, and the LOADEST regression software. The average daily flux during 2004–2007 was 71 kg C ha−1 yr−1 (392 Mt C d−1), an amount larger than measured in most northern temperate and boreal rivers. Distinct seasonal variation was observed in the relation between concentration and discharge (C–Q). During June through December (summer/fall), there was a relatively steep positive C–Q relation where concentration increased by a factor of 2–3 over the approximately 20-fold range of observed stream discharge for the Penobscot River near Eddington, Maine. In contrast, during January through May (winter/spring), DOC concentration did not increase with increasing discharge. In addition, we observed a major shift in the C–Q between 2004–2005 and 2006–2007, apparently resulting from unprecedented rainfall, runoff, and soil flushing beginning in late fall 2005. The relative contribution to the total Penobscot River basin DOC flux from each tributary varied dramatically by season, reflecting the role of large regulated reservoirs in certain basins. DOC concentration and flux per unit watershed area were highest in tributaries containing the largest areas in palustrine wetlands. Tributary DOC concentration and flux was positively correlated to percentage wetland area. Climatic or environmental changes that influence the magnitude or timing of river discharge or the abundance of wetlands will likely affect the export of DOC to the near-coastal ocean.

  11. Explosive Components Facility at Sandia National Laboratories, Albuquerque, New Mexico. Environmental assessment

    SciTech Connect

    Not Available

    1992-07-01

    The United States Department of Energy (DOE) has prepared an environmental assessment (EA) on the proposed Explosive Components Facility (ECF) at the Sandia National Laboratories, Albuquerque (SNL). This facility is needed to integrate, centralize, and enhance many of the explosive, neutron generation, and weapons testing programs currently in progress at SNL. In general, there is insufficient space in existing facilities for the development and testing activities required by modern explosives technologies. The EA examined the potential environmental impacts of the proposed ECF project and discussed potential alternatives. Based on the analyses in the EA, DOE has determined that the proposed action does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act (NEPA) of 1969, and CEQ regulations at 40 CFR 1508.18 and 1508.27. Therefore, an environmental impact statement (EIS) is not required, and the DOE is issuing this Finding of No Significant Impact (FONSI).

  12. Mantle-derived helium in sedimentary basins of Central Mediterranean: Geologic and tectonic constrains on fluids accumulation and migration.

    NASA Astrophysics Data System (ADS)

    Caracausi, Antonio; Grassa, Fausto; Pennino, Valentina; Rizzo, Andrea; Sulli, Attilio

    2013-04-01

    The geodynamics of the central Mediterranean is characterized by the interaction between the European plate and the African one. In this setting Sicily is a sector of the Appenine-Maghrebide accretionary prism, which is located between two areas affected by extensional tectonics (Sicily Channel to the south and the Thyrrenian back arc basin to the north). In the present study we present the first dataset of helium isotopic composition measured in fluids released from the central-western Sicily. With the aim to constrain the transfer system of fluids in this area we relate the results of geochemical investigations with the stratigraphy and structural setting, derived from field geology, deep boreholes and new seismic reflection, gravimetry and magnetometry data. Significant mantle-derived helium (0.4central western Sicily. CH4-dominated gases are released from mud volcanoes and feed everlasting fires mainly located in the central region, where upper Oligocene-Miocene terrigenous cover Mesozoic carbonatic units. The abundance of CH4, usually linked to the presence of hydrocarbons- and/or organic matter-rich layers, is almost exclusively linked to the Messinian evaporitic and pre-evaporitic levels (containing diatomites). On the other hand, CO2 is mainly associated to the thermal groundwaters circulating mainly in Mesozoic limestone and dolomite, which here constitute the bulk of the deformed wedge of the Sicilian chain (up to 15 km thick). In thermal waters, we found a positive correlation between water temperature, ranging between 22.1°C and 59°C, and helium isotopic ratio. Taking into consideration that helium rises from the mantle coupled to CO2 and others components, we discussed CO2 and CH4 coupled to helium. Our samples did no show any correlation between C/3He vs. R/Ra and only samples of the Sciacca thermal basin show C/3He in the typical ranges of

  13. REACH SPECIFIC CHANNEL STABILIZATION BASED ON COMPREHENSIVE EVALUATION OF VALLEY FILL HISTORY, ALLUVIAL ARCHITECTURE AND GROUNDWATER HYDROLOGY IN A MOUNTAIN STREAM IN THE CENTRAL GREAT BASIN, NEVADA

    EPA Science Inventory

    Kingston meadow, located in the Toiyabe Range, is one of many wet meadow complexes threatened by rapid channel incision in the mountain ranges of the central Great Basin. Channel incision can lower the baselevel for groundwater discharge and de-water meadow complexes resulting in...

  14. Geohydrologic feasibility study of the Northern and Central Appalachian basin areas for the potential application of a production process patented by Jack W. McIntyre

    SciTech Connect

    Kvasnicka, D.

    1994-03-01

    Geraghty & Miller, Inc. of Midland, Texas conducted geologic and hydrologic feasibility studies of the potential applicability of a patented (US Patent Office No. 4,766,957) process developed by Jack W. McIntyre for the recovery of natural gas from coalbed/sand formations in the Northern and Central Appalachian basin areas. General research, based on a review of published literature from both public and private sources, indicates that the generally thin, but numerous coalbeds found in the greater Appalachian Basin area do exhibit some potential for the application of this patented process. Estimates of total gas reserves in-place (Gas Research Institute, July 1991) for coalbeds in the Central and Northern Appalachian Basin areas are 5 trillion cubic feet (TCF) and 61 TCF respectively. Produced waters associated with coal deposits in the greater Appalachian Basin area can be characterized on the basis of established but limited production of coalbed methane. Central Appalachian coals generally produce small quantities of water (less than 50 barrels of water per day for the average producing well) which is high in total dissolved solids (TDS), greater than 30,000 parts per million (ppM). The chemical quality of water produced from these coal seams represents a significant disposal challenge to the operators of methane-producing wells in the Central Appalachian Basin. By contrast, water associated with the production of coalbed methane in the Northern Appalachian Basin is generally fair to good quality, and daily production volumes are low. However, the relatively slow desorption of methane gas from Northern Appalachian coals may result in a greater net volume of produced water over the economic life of the well. The well operator must respond to long-term disposal needs.

  15. Chemical evolution of groundwater in a drainage basin of Holocene age, east-central Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Wallick, E. I.

    1981-12-01

    Chemical evolution of groundwater in a small drainage basin of glacial origin (10,250 yr. B.P., based on radiocarbon age dating of gyttja from a closed saline lake in the basin) was studied in order to understand the generation of salts in surface-mined areas on the interior plains of Alberta. The basin was considered to be a natural analogue of a surface-disturbed area because of the large volumes of rock that had been redistributed by glaciers with the resulting change in topography and drainage. The distributions of hydraulic head, total dissolved solids (TDS), and environmental isotopes essentially reflect the superimposition of groundwater flow systems associated with the post-glacial topography upon a regional bedrock flow system of older but undertermined age. In the glacial drift aquifers and aquitards (sands and till), the groundwater composition was typically Ca-Mg-bicarbonate type at depths less than 30 m, but at depths of 30-100 m, the composition was Na-bicarbonate-sulfate type. In the deeper bedrock aquifers (> 100 m), Nabicarbonate-sulfate and Na-bicarbonate-chloride types were present. TDS was as low as 400 mg/l in the shallow drift aquifer, generally constant at ˜1000 mg/l in the deep drift and shallow bedrock aquifer, and over 1700 mg/l in the deep bedrock aquifer system. Chemical evolution of groundwater in the area appears to be dominated by two depth zones having different types of water-rock interaction. In the shallow drift zone, the dissolution of soil CO 2 in infiltrating groundwater, oxidation of organic carbon, sulfur and pyrite result in the formation of carbonic and sulfuric acids that attack carbonate and silicate minerals. On the basis of X-ray diffraction analysis, these minerals were calcite, dolomite, plagioclase feldspar, and smectite clays. However, in the deep regional bedrock aquifer, conditions are reducing (presence of methane), groundwater is alkaline (pH 8.6-10.3), and the Na-bicarbonate-chloride composition of groundwater

  16. 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

  17. Mictomys borealis (northern bog lemming) and the Wisconsin paleoecology of the east-central Great Basin

    NASA Astrophysics Data System (ADS)

    Mead, Jim I.; Bell, Christopher J.; Murray, Lyndon K.

    1992-03-01

    Teeth of northern bog lemming, Mictomys borealis, are reported from Cathedral and Smith Creek caves and represent the first Wisconsin remains of the genus from the Great Basin. Specimens from Cathedral Cave, Snake Range, are associated with U-series ages of 24,000 to 15,000 yr B.P. Previous work with pollen and packrat middens, dating to the same age as the Mictomys, indicate that Smith Creek Canyon contained a riparian, locally mesic community, including Picea engelmannii (spruce), Betula sp. (birch), Cercocarpus sp. (mountain mahogany), and Artemisia sp. (sagebrush) among other species. Exposed canyon slopes and the adjacent valley apparently contained a more xeric steppe community including sagebrush and Chenopodiineae species; rocky outcrop permitted Pinus flexilis (limber pine) and P. longaeva (bristlecone pine) to grow adjacent to Lake Bonneville or low in the canyon. The region apparently experienced a dry climate (not necessarily drier than today); however, Smith Creek Canyon was fed by glacial meltwater from Mt. Moriah. The northern bog lemming probably lived only in the riparian community and possibly on the north-facing slope below Cathedral Cave. Few canyons of the Snake Range would have had the unusually mesic conditions found in Smith Creek Canyon.

  18. Diatoms in coal: Miocene Venado Formation, Limon Basin, Costa Rica, Central America

    SciTech Connect

    Sanchez, J.D.; Coates, D.A.; Bradbury, J.P.; Bohor, B.F.

    1985-01-01

    Diatoms occur in coal in the Venado Formation on the southwest flank of the Limon Basin in Provincia Alajuela, northern Costa Rica. The Venado Formation contains more than 300 m of mudstones, siltstones, sandstones, limestones, and coal beds that crop out on the northeast flank of the Cordillera de Tilaran. Coal beds of unknown extent and correlation occur mainly in the middle part of the formation. The coal deposit here named informally the Pataste coal bed. Coal samples were examined with a scanning electron microscope and an x-ray analyzer attachment. Part A contains abundant diatoms and macerated diatom material and rare spicules of freshwater sponges. Diatoms identified are Melosira ambigua, Pinularia, Eunotia spp. and Achnathes exigua. Parts B and C of the coal bed contain fewer diatom remains and more sponge spicules than part A. The common presence of Melosira ambigua in A implies the proximity of open-water lacustrine environments. The other diatom species are benthic or bottom-dwelling forms that lived in slightly acidic, humic-rich paludal environments. Presumably, the swamp in which the coal was formed was most extensive during the deposition of A, and became progressively restricted thereafter. The increase of sponge spicules relative to diatoms in B and C suggests progressively, shallower lacustrine or restricted swamp conditions. The comparatively great abundance of biogenic opaline material in the coal is due to the influx of silica form a volcanic source represented by the tonstein layers.

  19. Active shortening and intermontane basin formation in the central Puna Plateau: Salar de Pocitos, NW Argentina (24°37'S, 67°03'W)

    NASA Astrophysics Data System (ADS)

    Strecker, Manfred; Bookhagen, Bodo; Freymark, Jessica; Pingel, Heiko; Alonso, Ricardo N.

    2015-04-01

    Similar to other Cenozoic orogenic plateaus, extensional tectonics associated with mafic volcanism typifies the Altiplano-Puna of the southern Central Andes, while the flanks of the plateau and adjacent foreland areas experience shortening. Extensional tectonism in the plateau region since the late Miocene has been explained with delamination of lithospheric mantle. However, new evidence for protracted basin-wide shortening in the Salar de Pocitos region in the south-central Puna documents that the kinematic changeover from shortening to extension is highly diachronous. In this study we assess the deformation and geomorphic history of the Salar de Pocitos region using DGPS surveys, CRN dating of deformed pediment surfaces, and U/Pb dating of volcanic ash horizons in deformed strata. With average elevations of about 3.7 km the Altiplano-Puna is a first-order morphotectonic province of the southern central Andes and constitutes the world's second largest orogenic plateau. With few exceptions the Andean plateau consists of internally drained, partly coalesced sedimentary basins that are mainly bordered by reverse-fault bounded ranges, 5 to 6 km high. While there are many unifying plateau characteristics in the Altiplano (north) and Puna (south), including internal drainage, semi-arid to arid climate and associated deposition of evaporites, there are notable differences between both plateau sectors. In contrast to the vast Altiplano basin of Bolivia, the Argentine Puna comprises numerous, smaller and partly coalesced basins that reflect continued comparmentalization by the combined effects of tectonism and volcanic activity. The N-S oriented Salar de Pocitos basin is the vestige of a formerly contiguous sedimentary basin within the Puna interior. Unlike many other basins in this region it is bordered by the limb of an anticline developed in Tertiary sedimentary rocks on the west, while the eastern border is a reverse-faulted range front. To the north and south the

  20. Comparison of Tarim and central Asian FSU basins, I: Phanerozoic paleogeography

    SciTech Connect

    Heubeck, C.; Shangyou N. )

    1996-01-01

    Large amounts of previously unpublished data on the petroleum geology of the FSU's Central Asian Republics and of China's Tarim region have found their way into the western public domain in the past few years. These data provide for the first time the opportunity to merge detailed stratigraphic, tectonic, and paleogeographic studies done during the past decades on both sides of the FSU-Chinese border and to place the results in a plate-tectonic and palinspastically restored reference frame. Major tectonic events affecting the active post-Silurian south-facing margin of Asia between the Caspian Sea and Tarim include (1) the collapse of the Kazakhstan arc fragments (ca. 400-300 Ma); (2) collision of YiIi with Tarim (ca. 375 Ma); (3) consolidation of the Turan Platform from pre-existing basement blocks (ca. 280-220 Ma), (4) collision of Tarim/Yili with the Kazakhstan arcs (ca. 260 Ma); (5) stabilization of a south-facing Triassic active margin (ca. 250 - 200 Ma); (6) accretion of Cimmeria (ca. 200 Ma) and associated reactivation events in Turan, Syr-Darja, and Tarim; (7) reactivation and modification of intracontinental structures during the collision of central Asia with India (ca. 55 Ma to present) and with the Arabian platform (ca. 25 Ma). Periodic large-scale flooding of denuded continental platforms (Turan, Tadjik) during sea-level highstands is recorded in the Jurassic, Mid-Late Cretaceous, and the Early Tertiary, resulting in extensive tracts of restricted marine sedimentary systems and marine incursions deep into central Asia (SW Tarim, Kuche Depression, Fergana, Turgay). Mesozoic-Cenozoic source rocks are sensitive to rapid lateral facies changes, and understanding their distribution requires detailed stratigraphic analysis. The attempted synthesis of data from China and the FSU with plate-tectonic concepts allows the transfer and testing of play concepts and hydrocarbons systems across the FSU-Chinese border.

  1. Transition from alkaline to calc-alkaline volcanism during evolution of the Paleoproterozoic Francevillian basin of eastern Gabon (Western Central Africa)

    NASA Astrophysics Data System (ADS)

    Thiéblemont, Denis; Bouton, Pascal; Préat, Alain; Goujou, Jean-Christian; Tegyey, Monique; Weber, Francis; Ebang Obiang, Michel; Joron, Jean Louis; Treuil, Michel

    2014-11-01

    We report new geochemical data for the volcanic and subvolcanic rocks associated with the evolution of the Francevillian basin of eastern Gabon during Paleoproterozoic times (c. 2.1-2 Ga). Filling of this basin has proceeded through four main sedimentary or volcano-sedimentary episodes, namely FA, FB, FC and FD. Volcanism started during the FB episode being present only in the northern part of the basin (Okondja sub-basin). This volcanism is ultramafic to trachytic in composition and displays a rather constant alkaline geochemical signature. This signature is typical of a within-plate environment, consistent with the rift-setting generally postulated for the Francevillian basin during the FB period. Following FB, the FC unit is 10-20 m-thick silicic horizon (jasper) attesting for a massive input of silica in the basin. Following FC, the FD unit is a c. 200-400 m-thick volcano-sedimentary sequence including felsic tuffs and epiclastic rocks. The geochemical signatures of these rocks are totally distinct from those of the FB alkaline lavas. High Th/Ta and La/Ta ratios attest for a calc-alkaline signature and slight fractionation between heavy rare-earth suggests melting at a rather low pressure. Such characteristics are comparable to those of felsic lavas associated with the Taupo zone of New Zealand, a modern ensialic back-arc basin. Following FD, the FE detrital unit is defined only in the Okondja region, probably associated with a late-stage collapse of the northern part of the basin. It is suggested that the alkaline to calc-alkaline volcanic transition reflects the evolution of the Francevillian basin from a diverging to a converging setting, in response to the onset of converging movements in the Eburnean Belt of Central Africa.

  2. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe.

    PubMed

    Conte, Annamaria; Candeloro, Luca; Ippoliti, Carla; Monaco, Federica; De Massis, Fabrizio; Bruno, Rossana; Di Sabatino, Daria; Danzetta, Maria Luisa; Benjelloun, Abdennasser; Belkadi, Bouchra; El Harrak, Mehdi; Declich, Silvia; Rizzo, Caterina; Hammami, Salah; Ben Hassine, Thameur; Calistri, Paolo; Savini, Giovanni

    2015-01-01

    West Nile virus (WNV) is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel. PMID:26717483

  3. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe

    PubMed Central

    Conte, Annamaria; Candeloro, Luca; Ippoliti, Carla; Monaco, Federica; De Massis, Fabrizio; Bruno, Rossana; Di Sabatino, Daria; Danzetta, Maria Luisa; Benjelloun, Abdennasser; Belkadi, Bouchra; El Harrak, Mehdi; Declich, Silvia; Rizzo, Caterina; Hammami, Salah; Ben Hassine, Thameur; Calistri, Paolo; Savini, Giovanni

    2015-01-01

    West Nile virus (WNV) is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel. PMID:26717483

  4. Relationships among vegetation, geomorphology and hydrology in the Bananal Island tropical wetlands, Araguaia River basin, Central Brazil

    NASA Astrophysics Data System (ADS)

    Valente, C. R.; Latrubesse, E. M.; Ferreira, L. G.

    2013-10-01

    The Bananal Plain spreading on the Middle Araguaia River basin in Central Brazil at the Cerrado-Amazonia ecotone is a unique system that sustains the largest seasonal wetlands of the Cerrado biome. The huge Bananal Plain is an intracratonic sedimentary basin filled with Pleistocene sediments of the Araguaia formation. Covering approximately two million hectares, the Bananal Island is a major geomorphologic feature of the Bananal plain. Fieldwork and the analysis of a temporal series of MODIS-VI and Landsat ETM images allowed us to discriminate Cerrado phyto-physiognomies on the Bananal Island. Maps of vegetation and geomorphologic units were created, and from the correlation between landforms and vegetation types we identified morpho-vegetation units. Our approach allowed us to postulate that Pleistocene landforms strongly influence, if not dominate, the distribution of vegetation units. For example, the distribution of current gallery forest is not only controlled by active floodplains, but also by alluvial belts abandoned by avulsion. Additionally, arboreal Cerrado vegetation is supported by laterite developed on the sediments of the Araguaia Formation. Some of these inactive landforms are in part modified by the present day geomorphologic processes and colonized by successional vegetation that varies from alluvial forest to Cerrado. Characterized by a very flat landscape with a hindered drainage, the muddy sediments of the Araguaia Formation and the high seasonal rainfall favor the development of regional seasonal wetlands. The Bananal plain is a key area for understanding the Quaternary climatic and biogeographic changes in tropical South America. The control exerted by relict Quaternary landforms on the current vegetation units demonstrates the strong links between geomorphologic aspects of the landscape and ecological patterns. This multidisciplinary approach provides a better understanding of the biogeographic patterns in the Cerrado-Amazon ecotone, which is

  5. Distribution, lithology and ages of late Cenozoic volcanism on the eastern margin of the Great Basin, West-Central Utah

    SciTech Connect

    Nash, W.P.

    1986-01-01

    The eastern margin of the Basin and Range province in central Utah is the locus of late Cenozoic volcanic activity and has witnessed several volcanic episodes within the last three million years. The Twin Peaks volcanic center became active 2.7 m.y. ago producing rhyodacite and rhyolite from a shallow silicic magma body accompanied by voluminous eruptions of basalt. Between about 1 and 0.3 m.y. ago there were eruptions of high silica rhyolite from a deep-seated magma source beneath the Mineral Mountains together with primitive and strongly fractionated mafic magmas of the Cove Fort subprovince. Within this volcanic area are two localities, Roosevelt Hot Springs and Sulfurdale, which have high temperature waters at or near the surface. To the north in the Black Rock Desert, volcanism extended from 1.5 m.y to only several hundred years ago. The activity was dominated by basaltic eruptions, but the area contains the youngest known rhyolite body in Utah (0.4 m.y.). Volcanic vents are located along major crustal discontinuities in the Black Rock Desert, along ring fracture systems at Twin Peaks, and are aligned along trends of north-south normal faulting in the Mineral Mountains and Cove Fort areas. The localization of volcanism is consistent with high strain rates on a regional scale associated with extension of the Basin and Range. The variety of lithologies observed is consistent with a model of fundamentally basaltic magmatism which augments melting in the lower crust to produce silicic magmas. The majority of the mafic magmas that reach the surface are modified by fractionation with the most primitive varieties erupted to the west.

  6. A molecular and isotopic study of palaeoenvironmental conditions through the middle Cambrian in the Georgina Basin, central Australia

    NASA Astrophysics Data System (ADS)

    Pagès, Anais; Schmid, Susanne; Edwards, Dianne; Barnes, Stephen; He, Nannan; Grice, Kliti

    2016-08-01

    The Cambrian period marks an important point in Earth's history with profound changes in the ocean's biogeochemistry and the occurrence of the most significant evolutionary event in the history of life, the Cambrian explosion. The Cambrian explosion is described as a succession of complex cycles of extinctions and radiations. This study integrates biomarkers and their compound-specific stable carbon isotopes to investigate the palaeoenvironmental depositional conditions in middle Cambrian (Series 3) sedimentary rocks (Thorntonia Limestone, Inca Formation and Currant Bush Limestone) from two drillholes in the Undilla Sub-basin in the eastern Georgina Basin, central Australia. The occurrence of photic zone euxinia (PZE) was detected throughout these three formations by the identification of green sulfur bacteria Chlorobiaceae-derived biomarkers, including a series of 2,3,6-aryl isoprenoids and the intact biomarker isorenieratane. Pulses of enhanced PZE conditions were detected in two core intervals (90-110 mKB, Currant Bush Limestone and 170-200 mKB, Inca Formation) by an increase in the 2,3,6-aryl isoprenoids and C19 biphenyl concentrations. These enhanced PZE conditions were followed by blooms of phytoplankton, as demonstrated by the increase in algal-derived biomarker (i.e. pristane, phytane and the C19n-alkane) concentrations and compound-specific isotopes. These observations confirm that palaeoenvironmental conditions were similar to those reported for the Permian/Triassic and Triassic/Jurassic mass extinction events. The sterane distributions varied across the three formations reflecting possible changes in the phytoplanktonic communities through time. Although a rise in atmospheric oxygen during the Cambrian has been previously associated with the rapid evolution of metazoans, the ecological challenges related to widespread anoxia must have had a major influence on the evolution of life in Cambrian oceans.

  7. 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.

  8. 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.

  9. Cenozoic foreland basin system in the central Andes of northwestern Argentina: Implications for Andean geodynamics and modes of deformation

    NASA Astrophysics Data System (ADS)

    Decelles, P. G.; Carrapa, B.; Horton, B. K.; Gehrels, G. E.

    2011-12-01

    Cenozoic strata in the central Andes of northwestern Argentina record the development and migration of a regional foreland basin system analogous to the modern Chaco-Paraná alluvial plain. Paleocene-lower Eocene fluvial and lacustrine deposits are overlain by middle-upper Eocene hypermature paleosols or an erosional disconformity representing 10-15 Myr. This `supersol/disconformity' zone is traceable over a 200,000 km2 area in the Andean thrust belt, and is overlain by 2-6 km of upward coarsening, eastward thinning, upper Eocene through lower Miocene fluvial and eolian deposits. Middle Miocene-Pliocene fluvial, lacustrine, and alluvial fan deposits occupy local depocenters with contractional growth structures. Paleocurrent and petrographic data demonstrate westerly provenance of quartzolithic and feldspatholithic sediments. Detrital zircon ages from Cenozoic sandstones cluster at 470-491, 522-544, 555-994, and 1024-1096 Ma. Proterozoic-Mesozoic clastic and igneous rocks in the Puna and Cordillera Oriental yield similar age clusters, and served as sources of the zircons in the Cenozoic deposits. Arc-derived zircons become prominent in Oligo-Miocene deposits and provide new chronostratigraphic constraints. Sediment accumulation rate increased from ˜20 m/Myr during Paleocene-Eocene time to 200-600 m/Myr during the middle to late Miocene. The new data suggest that a flexural foreland basin formed during Paleocene time and migrated at least 600 km eastward at an unsteady pace dictated by periods of abrupt eastward propagation of the orogenic strain front. Despite differences in deformation style between Bolivia and northwestern Argentina, lithosphere in these two regions flexed similarly in response to eastward encroachment of a comparable orogenic load beginning during late Paleocene time.

  10. Major Crustal Fault Zone Trends and Their Relation to Mineral Belts in the North-Central Great Basin, Nevada

    USGS Publications Warehouse

    Rodriguez, Brian D.; Sampson, Jay A.; Williams, Jackie M.

    2007-01-01

    The Great Basin physiographic province covers a large part of the western United States and contains one of the world's leading gold-producing areas, the Carlin Trend. In the Great Basin, many sedimentary-rock-hosted disseminated gold deposits occur along such linear mineral-occurrence trends. The distribution and genesis of these deposits is not fully understood, but most models indicate that regional tectonic structures play an important role in their spatial distribution. Over 100 magnetotelluric (MT) soundings were acquired between 1994 and 2001 by the U.S. Geological Survey to investigate crustal structures that may underlie the linear trends in north-central Nevada. MT sounding data were used to map changes in electrical resistivity as a function of depth that are related to subsurface lithologic and structural variations. Two-dimensional (2-D) resistivity modeling of the MT data reveals primarily northerly and northeasterly trending narrow 2-D conductors (1 to 30 ohm-m) extending to mid-crustal depths (5-20 km) that are interpreted to be major crustal fault zones. There are also a few westerly and northwesterly trending 2-D conductors. However, the great majority of the inferred crustal fault zones mapped using MT are perpendicular or oblique to the generally accepted trends. The correlation of strike of three crustal fault zones with the strike of the Carlin and Getchell trends and the Alligator Ridge district suggests they may have been the root fluid flow pathways that fed faults and fracture networks at shallower levels where gold precipitated in favorable host rocks. The abundant northeasterly crustal structures that do not correlate with the major trends may be structures that are open to fluid flow at the present time.

  11. Eustatic and climatic control on the Upper Muschelkalk Sea (late Anisian/Ladinian) in the Central European Basin

    NASA Astrophysics Data System (ADS)

    Franz, M.; Kaiser, S. I.; Fischer, J.; Heunisch, C.; Kustatscher, E.; Luppold, F. W.; Berner, U.; Röhling, H.-G.

    2015-12-01

    The Upper Muschelkalk in the Central European Basin (CEB) is a key example of eustatic and climatic controls on inland seas. The late Anisian rapid transgression from Tethyan waters culminated in a large semi-enclosed inland sea stretching across the CEB. Subsequently, the slow but successive retreat in the early Ladinian resulted in a small remnant sea. The pronounced stratal pattern architectures are translated into a framework of 3rd- and 4th-order T-R sequences. The latest Illyrian 3rd-order maximum flooding surface corresponds to maximum abundances of carbonates and marine phytoplankton. An euryhaline marine ecology is indicated by prasinophycean algae dominating over acritarchs and δ18OP values of 18.9-22.4‰ VSMOW corresponding to Tethyan