Science.gov

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. Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-95, with projections to 2020

    USGS Publications Warehouse

    Kernodle, J.M.

    1998-01-01

    The ground-water-flow model of the Albuquerque Basin (Kernodle, J.M., McAda, D.P., and Thorn, C.R., 1995, Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, with projections to 2020: U.S. Geological Survey Water-Resources Investigations Report 94-4251, 114 p.) was updated to include new information on the hydrogeologic framework (Hawley, J.W., Haase, C.S., and Lozinsky, R.P., 1995, An underground view of the Albuquerque Basin: Proceedings of the 39th Annual New Mexico Water Conference, November 3-4, 1994, p. 37-55). An additional year of ground-water-withdrawal data was appended to the simulation of the historical period and incorporated into the base for future projections to the year 2020. The revised model projects the simulated ground-water levels associated with an aerally enlarged occurrence of the relatively high hydraulic conductivity in the upper part of the Santa Fe Group east and west of the Rio Grande in the Albuquerque area and north to Bernalillo. Although the differences between the two model versions are substantial, the revised model does not contradict any previous conclusions about the effect of City of Albuquerque ground-water withdrawals on flow in the Rio Grande or the net benefits of an effort to conserve ground water. Recent revisions to the hydrogeologic model (Hawley, J.W., Haneberg, W.C., and Whitworth, P.M., in press, Hydrogeologic investigations in the Albuquerque Basin, central New Mexico, 1992-1995: Socorro, New Mexico Bureau of Mines and Mineral Resources Open- File Report 402) of the Albuquerque Basin eventually will require that this model version also be revised and updated.

  3. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through 2004

    USGS Publications Warehouse

    DeWees, R.K.

    2006-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the Albuquerque Basin are obtained solely from ground-water resources. An increase of approximately 20 percent in the population from 1991 to present also resulted in an increased demand for water. From April 1982 through September 1983, a network of wells was established to monitor changes in ground-water levels throughout the Albuquerque Basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. Currently (2004), the network consists of 234 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 155 sites through 2004. Water-level and other data for 71 sites are collected by other agencies. Water-level data for 8 sites of the 155 sites measured by the U.S. Geological Survey were not available for this report.

  4. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2011

    USGS Publications Warehouse

    Beman, Joseph E.

    2012-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and of about 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey 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. Currently (2011), the network consists of 126 wells and piezometers (a piezometer is a specialized well open to a specific depth in the aquifer and is often of small diameter and nested with other piezometers open to different depths). This report presents water-level data collected by U.S. Geological Survey personnel at those 126 sites through water year 2011 to better help the Albuquerque Bernalillo County Water Utility Authority manage water use.

  5. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2010

    USGS Publications Warehouse

    Beman, Joseph E.

    2011-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the basin human population from 1990 to 2000 and about a 22 percent increase from 2000 to 2010 also resulted in an increased demand for water. A network of wells was established by the U.S. Geological Survey in cooperation with the City of Albuquerque to monitor changes in groundwater levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2010), the network consists of 124 wells and piezometers (a piezometer is a small-diameter subwell usually nested within a larger well). To better help the Albuquerque Bernalillo County Water Utility Authority manage water use, this report presents water-level data collected by U.S. Geological Survey personnel at those 124 sites through water year 2010.

  6. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2012

    USGS Publications Warehouse

    Beman, Joseph E.

    2013-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25-40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22 percent increase from 2000 to 2010 resulted in an increased demand for water. 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. Currently (2012), the network consists of 126 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 (ABCWUA), currently (2012) measures and reports water levels from the 126 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 126 sites through water year 2012.

  7. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2013

    USGS Publications Warehouse

    Beman, Joseph E.

    2014-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when treatment and distribution of surface water from the Rio Grande began. A population increase of about 20 percent in the basin from 1990 to 2000 and a 22-percent increase from 2000 to 2010 resulted in an increased demand for water. 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. Currently (2013), the network consists of 123 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 (2013) measures and reports water levels from the 123 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 123 sites through water year 2013.

  8. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2015

    USGS Publications Warehouse

    Beman, Joseph E.; Bryant, Christina F.

    2016-10-27

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25–40 miles wide. The basin is hydrologically defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompasses the structural Rio Grande Rift between San Acacia to the south and Cochiti Lake to the north. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when the Albuquerque Bernalillo County Water Utility Authority (ABCWUA) began treatment and distribution of surface water from the Rio Grande through the San Juan-Chama Drinking Water Project. A 20-percent population increase in the basin from 1990 to 2000 and a 22-percent population increase from 2000 to 2010 may have resulted in an increased demand for water in areas within the basin.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 Albuquerque Basin. In 1983, this network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. The network currently (2015) consists of 124 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 ABCWUA, currently (2015) measures and reports water levels from the 124 wells and piezometers in the network; this report presents water-level data collected by USGS personnel at those 124 sites through water year 2015 (October 1, 2014, through September 30, 2015).

  9. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2006

    USGS Publications Warehouse

    Beman, Joseph E.

    2007-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2007) obtained solely from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. From April 1982 through September 1983, a network of wells was established to monitor changes in ground-water levels throughout the basin. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly. Currently (2007), the network consists of 133 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 133 sites through 2007.

  10. Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-1994, with projections to 2020

    USGS Publications Warehouse

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

    1995-01-01

    This report describes a three-dimensional finite-difference ground-water-flow model of the Santa Fe Group aquifer system in the Albuquerque Basin, which comprises the Santa Fe Group (late Oligocene to middle Pleistocene age) and overlying valley and basin-fill deposits (Pleistocene to Holocene age). The model is designed to be flexible and adaptive to new geologic and hydrologic information as it becomes available by using a geographic information system as a data-base manager to interface with the model. The aquifer system was defined and quantified in the model consistent with the current (July 1994) understanding of the structural and geohydrologic framework of the basin. Rather than putting the model through a rigorous calibration process, dis- crepancies between simulated and measured responses in hydraulic head were taken to indicate that the understanding of a local part of the aquifer system was incomplete or incorrect. The model simulates ground-water flow over an area of about 2,400 square miles to a depth of 1,730 to about 2,020 feet below the water table with 244 rows, 178 columns, and 11 layers. Of the 477,752 cells in the model, 310,376 are active. The top four model layers approximate the 80-foot thickness of alluvium in the incised and refilled valley of the Rio Grande to provide detail of the effect of ground-water withdrawals on the surface- water system. Away from the valley these four layers represent the interval within the Santa Fe Group aquifer system between the com- puted predevelopment water table and a level 80 feet below the grade of the Rio Grande. The simulations include initial condi- tions (steady-state), the 1901-1994 historical period, and four possible ground-water withdrawal scenarios from 1994 to 2020. The model indicates that for the year ending in March 1994, net surface-water loss in the basin resulting from the City of Albuquerque's ground-water withdrawal totaled about 53,000 acre- feet. The balance of the about 123

  11. Water-level data for the Albuquerque Basin and adjacent areas, central New Mexico, period of record through September 30, 2009

    USGS Publications Warehouse

    Beman, Joseph E.; Torres, Leeanna T.

    2010-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin were obtained solely from groundwater resources until December 2008, when surface water from the Rio Grande began being treated and integrated into the system. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in groundwater levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2009), the network consists of 131 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 123 sites through water year 2009. In addition, data from four wells (Sites 140, 147, 148, and 149) owned, maintained, and measured by Sandia National Laboratories and three from Kirtland Air Force Base (Sites 119, 125, and 126) are presented in this report.

  12. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2007

    USGS Publications Warehouse

    Beman, Joseph E.

    2008-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2007) obtained solely from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in ground-water levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2007), the network consists of 131 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 131 sites through water-year 2007. Data from five sites (Sites 9, 10, 31, 71 and 78) were not measured during the 2007 water-year, but are included in this report because recent data are useful for comparison and (or) data have been collected that will be included in the water-year 2008 report.

  13. Water-Level Data for the Albuquerque Basin and Adjacent Areas, Central New Mexico, Period of Record Through September 30, 2008

    USGS Publications Warehouse

    Beman, Joseph E.

    2009-01-01

    The Albuquerque Basin, located in central New Mexico, is about 100 miles long and 25 to 40 miles wide. The basin is defined as the extent of consolidated and unconsolidated deposits of Tertiary and Quaternary age that encompass the structural Rio Grande Rift within the basin. Drinking-water supplies throughout the basin are currently (2008) obtained soley from ground-water resources. An increase of about 20 percent in the population from 1990 to 2000 also resulted in an increased demand for water. A network of wells was established to monitor changes in ground-water levels throughout the basin from April 1982 through September 1983. This network consisted of 6 wells with analog-to-digital recorders and 27 wells where water levels were measured monthly in 1983. Currently (2008), the network consists of 144 wells and piezometers. This report presents water-level data collected by U.S. Geological Survey personnel at 125 sites through water-year 2008. In addition, data from 19 wells (Sites 127-30, 132-134, 136, 138-142 and 144-149) owned, maintained, and measured by Sandia National Laboratories are presented in this report.

  14. Potential for a basin-centered gas accumulation in the Albuquerque Basin, New Mexico

    USGS Publications Warehouse

    Johnson, Ronald C.; Finn, Thomsa M.; Nuccio, Vito F.

    2001-01-01

    The potential that a basin-centered or continuous-type gas accumulation is present in the Albuquerque Basin in central New Mexico was investigated. The Albuquerque Basin is one of the many rift basins that make up the Rio Grand rift system, an area of active extension from Oligocene to recent time. The basin is significantly different from other Rocky Mountain basins that contain basin-centered gas accumulations because it is actively subsiding and is at near maximum burial and heating conditions at the present time. Burial reconstructions suggest that Cretaceous-age source rocks began to generate gas in the deeper parts of the basin about 20 million years ago and are still generating large amounts of gas. The high mud weights typically used while drilling the Cretaceous interval in the deeper areas of the basin suggest some degree of over-pressuring. Gas shows are commonly reported while drilling through the Cretaceous interval; however, attempts to complete gas wells in the Cretaceous have resulted in subeconomic quantities of gas, primarily because of low permeabilities. Little water has been reported. All of these characteristics suggest that a basin-centered gas accumulation of some sort is present in the Albuquerque Basin.

  15. 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.

    2015-10-21

    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).

  16. 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

  17. Geologic Map of the Albuquerque 30' x 60' Quadrangle, North-Central New Mexico

    USGS Publications Warehouse

    Williams, Paul L.; Cole, James C.

    2007-01-01

    The Albuquerque 30' x 60' quadrangle spans the Rio Grande rift between the Colorado Plateau and Great Plains geologic provinces, and includes parts of the Basin and Range and Southern Rocky Mountain physiographic provinces. Geologic units exposed in the quadrangle range in age from Early Proterozoic schist and granite to modern river alluvium. The principal geologic features of the area, however, chiefly reflect contractional folding and thrusting of the Late Cretaceous Laramide orogeny and the Neogene extension of the Rio Grande rift. Significant parts of the history of the rift in this region are displayed and documented by the geology exposed in the Albuquerque quadrangle. Post-Laramide erosion, beginning at about 60 Ma, is recorded by the Diamond Tail and Galisteo Formations (upper Paleocene and Eocene) that are preserved in the Hagan Basin and around the uplifted margins of the younger Rio Grande rift. Intermediate volcaniclastic deposits of the Espinaso Formation (upper Eocene and Oligocene) were shed in and around the contemporaneous volcanic-intrusive complexes of the Ortiz porphyry belt in the northeastern part of the quadrangle. The earliest fluvial sediments attributed to extension in the Rio Grande rift in this area are the Tanos and Blackshare Formations (upper Oligocene and Miocene) in the Hagan Basin, which indicate extension was underway by 25 Ma. Farther west, the oldest rift-filling sediments are eolian sand and interdune silty deposits of the Zia Formation (lower to middle Miocene). Major extension occurred during the Miocene, but subsidence and sedimentation were highly irregular from place to place. Parts of three rift sub-basins are known within the Albuquerque quadrangle, each basin locally as deep as about 14,000 ft, separated by less-extended zones (structural horsts) where the rift fill is much thinner. The geometry of these early, deep rift sub-basins suggests the primary extension direction was oriented northeast-southwest. Significant

  18. Plan of study to quantify the hydrologic relations between the Rio Grande and the Santa Fe Group aquifer system near Albuquerque, central New Mexico

    USGS Publications Warehouse

    McAda, D.P.

    1996-01-01

    The Albuquerque Basin in central New Mexico covers an area of about 3,060 square miles. Ground water from the Santa Fe Group aquifer system of the Albuquerque Basin is the principal source of water for municipal, domestic, commercial, and industrial uses in the Albuquerque area, an area of about 410 square miles. Ground- water withdrawal in the basin has increased from about 97,000 acre-feet in 1970 to about 171,000 acre-feet in 1994. About 92 percent of the 1994 total was withdrawn in the Albuquerque area. Management of ground water in the Albuquerque Basin is related to the surface water in the Rio Grande. Because the aquifer system is hydraulically connected to the Rio Grande and water in the river is fully appropriated, the ability to reliably estimate the effects of ground-water withdrawals on flow in the river is important. This report describes the components of the Rio Grande/Santa Fe Group aquifer system in the Albuquerque area and the data availability and data and interpretation needs relating to those components, and presents a plan of study to quantify the hydrologic relations between the Rio Grande and the Santa Fe Group aquifer system. The information needs related to the components of the river/aquifer system are prioritized. Information that is necessary to improve the understanding or quantification of a component in the river/aquifer system is prioritized as essential. Information that could add additional understanding of the system, but would not be necessary to improve the quantification of the system, is prioritized as useful. The study elements are prioritized in the same manner as the information needs; study elements designed to provide information considered necessary to improve the quantification of the system are prioritized as essential, and those designed to provide information that would add additional understanding of the system, but would not be necessary to improve the quantification of the system, are prioritized as useful.

  19. 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

  20. 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.

  1. U.S. Geological Survey middle Rio Grande basin study; proceedings of the third annual workshop, Albuquerque, New Mexico, February 24-25, 1999

    USGS Publications Warehouse

    Bartolino, James R.

    1999-01-01

    Approximately 40 percent (about 600,000 people) of the total population of New Mexico lives within the Middle Rio Grande Basin, which includes the City of Albuquerque. Ongoing analyses of the central portion of the Middle Rio Grande Basin by the U.S. Geological Survey (USGS) in cooperation with the City of Albuquerque and other agencies have shown that ground water in the basin is not as readily accessible as earlier studies indicated. A more complete characterization of the ground-water resources of the entire Middle Rio Grande Basin is hampered by a scarcity of data in the northern and southern areas of the basin. The USGS Middle Rio Grande Basin study is a 5-year effort by the USGS and other agencies to improve the understanding of the hydrology, geology, and land-surface characteristics of the Middle Rio Grande Basin. The primary objective of this study is to improve the understanding of the water resources of the basin. Of particular interest is to determine the extent of hydrologic connection between the Rio Grande and the Santa Fe Group aquifer. Additionally, ground-water quality affects the availability of water supplies in the basin. Improving the existing USGS-constructed ground-water flow model of the Middle Rio Grande Basin will integrate all the various tasks that improve our knowledge of the various components of the Middle Rio Grande water budget. Part of this improvement will be accompanied by extended knowledge of the aquifer system beyond the Albuquerque area into the northern and southern reaches of the basin. Other improvements will be based on understanding gained through process-oriented research and improved geologic characterization of the deposits. The USGS and cooperating agencies will study the hydrology, geology, and land-surface characteristics of the basin to provide the scientific information needed for water-resources management and for managers to plan for water supplies needed for a growing population. To facilitate exchange of

  2. 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.

  3. New perspectives on the geometry of the Albuquerque Basin, Rio Grande rift, New Mexico: Insights from geophysical models of rift-fill thickness

    USGS Publications Warehouse

    Grauch, V. J.; Connell, Sean D.

    2013-01-01

    Discrepancies among previous models of the geometry of the Albuquerque Basin motivated us to develop a new model using a comprehensive approach. Capitalizing on a natural separation between the densities of mainly Neogene basin fill (Santa Fe Group) and those of older rocks, we developed a three-dimensional (3D) geophysical model of syn-rift basin-fill thickness that incorporates well data, seismic-reflection data, geologic cross sections, and other geophysical data in a constrained gravity inversion. Although the resulting model does not show structures directly, it elucidates important aspects of basin geometry. The main features are three, 3–5-km-deep, interconnected structural depressions, which increase in size, complexity, and segmentation from north to south: the Santo Domingo, Calabacillas, and Belen subbasins. The increase in segmentation and complexity may reflect a transition of the Rio Grande rift from well-defined structural depressions in the north to multiple, segmented basins within a broader region of crustal extension to the south. The modeled geometry of the subbasins and their connections differs from a widely accepted structural model based primarily on seismic-reflection interpretations. Key elements of the previous model are an east-tilted half-graben block on the north separated from a west-tilted half-graben block on the south by a southwest-trending, scissor-like transfer zone. Instead, we find multiple subbasins with predominantly easterly tilts for much of the Albuquerque Basin, a restricted region of westward tilting in the southwestern part of the basin, and a northwesterly trending antiform dividing subbasins in the center of the basin instead of a major scissor-like transfer zone. The overall eastward tilt indicated by the 3D geophysical model generally conforms to stratal tilts observed for the syn-rift succession, implying a prolonged eastward tilting of the basin during Miocene time. An extensive north-south synform in the

  4. 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

  5. Reconnaissance of hydrology, land use, ground-water chemistry, and effects of land use on ground-water chemistry in the Albuquerque-Belen basin, New Mexico

    USGS Publications Warehouse

    Anderholm, S.K.

    1987-01-01

    In 1984, the U.S. Geological Survey began regional assessments of groundwater contamination in 14 areas, one of which was the Albuquerque-Belen basin. Groundwater recharge occurs along the basin margins. Groundwater discharge occurs as evapotranspiration in the Rio Grande valley, pumpage, and groundwater flow to the Socorro basin. Open-space land use, which primarily is used for grazing livestock, occupies the majority of the basin. In the Rio Grande valley, agricultural and residential land uses are predominant; in the area near Albuquerque, the land also is used for commercial, institutional , and industrial purposes. The Albuquerque-Belen basin was divided into seven zones on the basis of water chemistry. These water-chemistry zones indicate that large variations in water chemistry exist in the basin as the result of natural processes. Groundwater in the majority of the Albuquerque-Belen basin has a relatively low susceptibility to contamination because the depth to water is > 100 ft and there is virtually no natural mechanism for recharge to the groundwater system. Groundwater in the Rio Grande valley has a relatively high susceptibility to contamination because the depth to water is generally < 30 ft and there are many types of recharge to the groundwater system. Changes in land use may cause changes in the chemical composition of recharge to the groundwater system. The relatively large concentrations of dissolved iron in the Rio Grande valley near Albuquerque may result from the change from agricultural land use to residential land use. Recharge associated with agricultural land use is relatively oxidized because the water is in equilibrium with the atmosphere, whereas recharge associated with residential land use (onsite waste-disposal effluent) is relatively reduced and has larger concentrations of organic carbon, biological oxygen demand, and chemical oxygen demand. The constituents in the onsite waste-disposal effluent could cause reducing conditions in

  6. Central Nebraska river basins Nebraska

    USGS Publications Warehouse

    Huntzinger, Thomas L.; Ellis, Michael J.

    1993-01-01

    The Central Nebraska Basins (NAWQA) study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Platte River flows are variable of diversions, but the Loup and Elkhorn Rivers originate in an area of dune sand covered by grassland that generates consistent base flows. Ground water has no regional confining units and the system is a water table aquifer throughout. Macroinvertebrate and fish taxa were related to stream flow. One of the four wetland complexes includes habitat for threatened and endangered bird species. A water quality assessments will be based on the differences in environmental setting in each of four subunits within the study unit.

  7. 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

  8. 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.

  9. 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)

  10. 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

  11. 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...

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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…

  18. 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

  19. Ground-water monitoring in the Albuquerque area

    USGS Publications Warehouse

    Thorn, Condé R.

    1996-01-01

    At present (1996), all drinking water for Albuquerque residents comes from ground-water reserves. The Albuquerque area is the largest population center in the State and the largest consumer of ground water. Recent reports concerning the water resources of the Albuquerque area suggest that the Albuquerque Basin may soon face serious water-availability and water-quality problems due to anticipated ground-water development. Recent studies completed by the U.S. Geological Survey (USGS) have improved the understanding of the ground-water resources in the Albuquerque Basin. These studies have indicated that the more permeable units within the aquifer system--the upper Santa Fe Group--are less extensive than previously thought, and that water-levels have declined as much as 160 feet.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

    USGS Publications Warehouse

    Anderholm, Scott K.

    1997-01-01

    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. Samples were analyzed for selected common constituents, nutrients, trace elements, radionuclides, volatile organic compounds, and pesticides. The study area, which is in the Albuquerque Basin in central New Mexico, was limited to the Rio Grande flood plain; depth to water in this area generally is less than 25 feet. The amount and composition of recharge to the shallow ground-water system are important factors that affect shallow ground-water composition in this area. Important sources of recharge that affect shallow ground-water quality in the area include infiltration of surface water, which is used in agricultural land-use areas to irrigate crops, and infiltration of septic-system effluent in residential areas. Agricultural land use represents about 28 percent of the area, and residential land use represents about 35 percent of the total study area. In most of the study area, agricultural land use is interspersed with residential land use and neither is the dominant land use in the area. Land use in the study area historically has been changing from agricultural to urban. The composition of shallow ground water in the study area varies considerably. The dissolved solids concentration in shallow ground water in the study area ranges from 272 to 1,650 milligrams per liter, although the relative percentages of selected cations and anions do not vary substantially. Calcium generally is the dominant cation and bicarbonate generally is the dominant anion. Concentrations of nutrients generally were less than 1 milligram per liter. The concentration of many trace elements in shallow ground water was below or slightly above 1 microgram per liter and there was little variation in the concentrations. Barium, iron, manganese

  5. Development of the central Carpathian Paleogene basin, west Carpathians, Slovakia

    SciTech Connect

    Nemcok, M. ); Neese, D.G. )

    1993-09-01

    The central Carpathian Paleogene basin, corresponding to one of the regions of Slovakia having a hydrocarbon potential, forms part of the Carpathian system. In the west Carpathians, synorogenic sediments, derived from the rising orogene, comprise an up to 3.5-km-thick sequence of Middle Eocene to Early Oligocene clastics. Flysch-type sediments dominate and are locally cut by canyon-focused submarine fans. The morphology of the floor of the central Carpathian Paleogene basin developed during the Albian and Maastrichtian in response to pre-Senonian nappe emplacement in the inner Carpathians and Late Cretaceous thrusting in the Pieniny Klippen belt. By the end of the Cretaceous, the inner Carpathians formed an emergent orogenic belt, providing a southern source for the sedimentary fill of the central Carpathian Paleogene basin. To the north, this basin was bounded by the Pieniny Klippen belt, forming at that time an irregular chain of islands, upheld by compressionally deformed pre-Tertiary rocks. Uplift of this northern barrier may explain the development of the central Carpathian Paleogene current system. Senonian shortening was subparallel to the present strike of the Pieniny Klippen belt. During the Paleogene and Miocene, shortening changed to a northern or northeastern direction. Differential shortening gave rise to the development of major strike-slip zones and numerous strike-slip faults that accommodated differential motion of thrust slices along the orogenic front. The northern, frontal portions of the basin were shortened by thrusting, whereas its basinal and proximal parts were affected by contemporaneous transtensional strike-slip faulting. Paleogene uplift of the frontal part of the evolving mountain belt is recorded by high-slump activity in areas of flysch deposition. A minimum of 2 km of sediments are missing from the basin due to Miocene erosion. At present, only structural remnants of the ancestral Paleogene basin are preserved.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Vitrinite Reflectance Data for the Wind River Basin, Central Wyoming

    USGS Publications Warehouse

    Finn, Thomas M.; Roberts, Laura N.R.; Pawlewicz, Mark J.

    2006-01-01

    Introduction: The Wind River Basin is a large Laramide (Late Cretaceous through Eocene) structural and sedimentary basin that encompasses about 7,400 mi2 in central Wyoming. The basin boundaries are defined by fault-bounded Laramide uplifts that surround it, including the Owl Creek and Bighorn Mountains to the north, Wind River Range to the west, Granite Mountains to the south, and Casper Arch to the east. The purpose of this report is to present new vitrinite reflectance data to be used in support of the U.S Geological Survey assessment of undiscovered oil and gas resources of the Wind River Basin. One hundred and nineteen samples were collected from Jurassic through Tertiary rocks, mostly coal-bearing strata, in an effort to better understand and characterize the thermal maturation and burial history of potential source rocks.

  11. 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.

  12. 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...

  13. 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.

  14. Sources of dissolved salts in the central Murray Basin, Australia

    USGS Publications Warehouse

    Jones, B.F.; Hanor, J.S.; Evans, W.R.

    1994-01-01

    Large areas of the Australian continent contain scattered saline lakes underlain by shallow saline groundwaters of regional extent and debated origin. The normative salt composition of subsurface pore fluids extracted by squeezing cores collected during deep drilling at Piangil West 2 in the central Murray Basin in southeastern Australia, and of surface and shallow subsurface brines produced by subaerial evaporation in the nearby Lake Tyrrell systems, helps constrain interpretation of the origin of dissolved solutes in the groundwaters of this part of the continent. Although regional sedimentation in the Murray Basin has been dominantly continental except for a marine transgression in Oligocene-Pliocene time, most of the solutes in saline surface and subsurface waters in the central Murray Basin have a distinctly marine character. Some of the Tyrrell waters, to the southwest of Piangil West 2, show the increase in NaCl and decrease in sulfate salts expected with evaporative concentration and gypsum precipitation in an ephemeral saline lake or playa environment. The salt norms for most of the subsurface saline waters at Piangil West 2 are compatible with the dilution of variably fractionated marine bitterns slightly depleted in sodium salts, similar to the more evolved brines at Lake Tyrrell, which have recharged downward after evaporation at the surface and then dissolved a variable amount of gypsum at depth. Apparently over the last 0.5 Ma significant quantities of marine salt have been blown into the Murray Basin as aerosols which have subsequently been leached into shallow regional groundwater systems basin-wide, and have been transported laterally into areas of large evaporative loss in the central part of the basin. This origin for the solutes helps explain why the isotopic compositions of most of the subsurface saline waters at Piangil West 2 have a strong meteoric signature, whereas the dissolved salts in these waters appear similar to a marine assemblage

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Hydrology of the Estancia Basin, central New Mexico

    USGS Publications Warehouse

    White, R.R.

    1993-01-01

    The Estancia Basin of central New Mexico is a topographically closed basin that ranges in altitude from 6,000 feet to more than 10,000 feet above sea level. In the center of the basin a valley-fill aquifer of Quaternary age is as much as 400 feet thick. Limestone of the Madera Group of Pennsylvanian and Permian age crops out over most of the southwestern part of the basin. Large-scale ground-water withdrawals for irrigation began about 1950. Between 1950 and 1985, water levels declined 50 to 60 feet in a number of places. From 1985 to the present (1989), however, a small rise in water level has been measured in a number of wells; this rise can be attributed to decreased ground-water withdrawals resulting from a government crop- reduction program and also to several years of heavy winter snowfall. Continuous water-level recorders were placed on three wells from 1986 to 1988. Two of these wells showed short-term water-level changes characteristic of unconfined aquifers, whereas the other showed changes characteristic of confined aquifers. All three wells showed water-level changes caused by barometric-pressure changes. Six series of miscellaneous measurements and two gain-and-loss (seepage) studies were made in streams in the south- western part of the basin. These measurements showed an extreme variability in discharge under different climatic conditions. The specific conductance of water in much of the southwestern part of the basin ranges from 350 to 550 microsiemens per centimeter at 25 degrees Celsius. East of State Highway 41 in the area of the salt lakes, water quality is highly dependent on depth in the aquifer. Specific- conductance values ranging from about 4,000 to 6,000 microsiemens were measured in water samples from wells in the center of the basin during this study, but previous studies have identified water samples having specific-conductance values of as much as 187,000 microsiemens. A comparison of specific- conductance measurements and laboratory

  3. 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.

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

    USGS Publications Warehouse

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

    1982-01-01

    The Salmon River basin drains approximately 13,000 square miles in central Idaho underlain by the Idaho batholith. Geologic units in the basin include igneous, sedimentary, and metamorphic rocks and granitic rocks predominate. Water from thermal springs ranges in temperature from 20.5 degrees to 94.0 degrees 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 degrees to 184 degrees Celsius. Tritium concentrations in sampled thermal waters are near zero and indicate the waters are at least 100 years old and may be considerably older. Stable-isotope data indicate it is unlikely that a single area of recharge or a single hot-water reservoir supplies all hot springs in the basin. Thermal springs discharged at least 15,800 acre-feet of water in 1980. Associated convective heat flux is 27 million calories per second. (USGS)

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. National Water-Quality Assessment Program: Central Arizona Basins

    USGS Publications Warehouse

    Cordy, Gail E.

    1994-01-01

    In 1991, the U.S. Geological Survey (USGS) began to implement a full-scale National Water-Quality Assessment (NAWQA) program. The long-term goals of the NAWQA program are to describe the status and trends in the quality of a large, representative part of the Nation's surface-water and ground-water resources and to provide a sound, scientific understanding of the primary natural and human factors affecting the quality of these resources. In meeting these goals, the program will produce a wealth of water-quality information that will be useful to policymakers and managers at the National, State, and local levels. Studies of 60 hydrologic systems that include parts of most major river basins and aquifer systems (study-unit investigations) are the building blocks of the national assessment. The 60 study units range in size from 1,000 to about 60,000 mi2 and represent 60 to 70 percent of the Nation's water use and population served by public water supplies. Twenty study-unit investigations were started in 1991, 20 additional studies started in 1994, and 20 more are planned to start in 1997. The Central Arizona Basins study unit began assessment activities in 1994.

  10. 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.

  11. Recent sedimentation patterns within the central Atchafalaya Basin, Louisiana

    USGS Publications Warehouse

    Hupp, C.R.; Demas, C.R.; Kroes, D.E.; Day, R.H.; Doyle, T.W.

    2008-01-01

    Sediment deposition and storage are important functions of forested bottomlands, yet documentation and interpretation of sedimentation processes in these systems remain incomplete. Our study was located in the central Atchafalaya Basin, Louisiana, a distributary of the Mississippi River and contains the largest contiguously forested riparian wetland in North America, which suffers from high sedimentation in some areas and hypoxia in others. We established 20 floodplain transects reflecting the distribution of depositional environments within the central Basin and monitored general and local sediment deposition patterns over a three-year period (2000-2003). Deposition rate, sediment texture, bulk density, and loss on ignition (LOI, percent organic material) were determined near or just above artificial markers (clay pads) located at each station per transect. Transect mean sedimentation rates ranged from about 2 to 42 mm/yr, mean percent organic material ranged from about 7% to 28%, mean percent sand (> 63 ??) ranged from about 5% to 44%, and bulk density varied from about 0.4 to 1.3. The sites were categorized into five statistically different clusters based on sedimentation rate; most of these could be characterized by a suite of parameters that included hydroperiod, source(s) of sediment-laden water, hydraulic connectivity, flow stagnation, and local geomorphic setting along transect (levee versus backswamp), which lead to distinct spatial sedimentation patterns. Sites with low elevation (long hydroperiod), high hydraulic connectivity to multiple sources of sediment-laden water, and hydraulic damming (flow stagnation) featured the highest amounts of sediment trapping; the converse in any of these factors typically diminished sediment trapping. Based on aerial extent of clusters, the study area potentially traps 6,720,000 Mg of sediment annually, of which, 820,000 Mg represent organic materials. Thus, the Atchafalaya Basin plays a substantial role in lowland

  12. 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.

  13. Groundwater chemistry and palaeorecharge in the Amadeus Basin, Central Australia

    NASA Astrophysics Data System (ADS)

    Jacobson, G.; Calf, G. E.; Jankowski, J.; McDonald, P. S.

    1989-08-01

    Carbon isotope chemistry indicates episodic palaeorecharge of groundwater in the arid Amadeus Basin, central Australia. In this hydrogeologically complex region, groundwater has been recharged by three important mechanisms: direct infiltration of rainwater through sand dune cover or fissures in calcrete; through river bed sands following floods; and through joints in bedrock outcrops. Modern and Holocene groundwaters (0-5000 years B.P.) are found in the unconfined calcrete and sand dune aquifers which have evolved hydrochemically to Cl-SO 4-Na waters with Ca and Mg, as a result of evaporative concentration. Holocene groundwaters (3-10,000 years B.P.) have been dated in river bed recharge situations; these groundwaters are mainly of the HCO 3-Cl-Na type, with Ca and Mg, and preserve the hydrochemical signature of the flood recharge waters. Most groundwater sampled in the folded and jointed rocks of the basin has a low modern 14C content and was recharged in the Holocene and late Pleistocene (12-32,000 years B.P.). These waters are intermediate in their ionic composition, covering a spectrum between the HCO 3-Cl-Na and Cl-SO 4-Na types; solution is the dominant process int heir hydrochemical evolution. Stable isotope signatures and derived parameters indicate that the intensity of rainfall is an important factor in the evolution of arid-zone groundwaters. Modern reharged is limited implying that projected large scale groundwater development in this region will use an effectively nonrenewable resource and should be managed accordingly.

  14. 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

  15. 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.

  16. Hexavalent chromium contamination in groundwaters of Thiva Basin, central Greece.

    PubMed

    Tziritis, Evangelos; Kelepertzis, Efstratios; Korres, George; Perivolaris, Dimitrios; Repani, Stella

    2012-11-01

    There is an increasing concern regarding elevated levels of Cr(VI) in the environment due to its higher mobility and toxicity compared to the trivalent form. Anomalous hexavalent chromium concentrations (up to 212 μg/L) were determined in irrigated groundwaters from the wider area of Thiva Basin (central Greece), frequently exceeding the permissible limit for human consumption (50 μg/L for total Cr). Based on the spatial distribution of Cr(VI) values, two groups of groundwater samples were distinguished, possibly reflecting different natural and/or anthropogenic factors that govern the levels of contamination. The first group is spatially located northwards of Thiva town and is consisted of concentrations that range from 13 to 212 μg/L (median 58 μg/L), while the second group is located near Mouriki village and Cr(VI) values range from <9 to 14 μg/L. The Cr(VI) chemical anomalies represent an important social problem because the agricultural products of this region are a major vegetable supply for Greece, bringing up the urgent need to evaluate the health effects associated with Cr(VI) exposure by ingesting the potentially contaminated foods.

  17. Sedimentation and subsidence patterns in the central and north basins of Lake Baikal from seismic stratigraphy

    USGS Publications Warehouse

    Moore, T.C.; Klitgord, Kim D.; Golmshtok, A.J.; Weber, E.

    1997-01-01

    Comparison of sedimentation patterns, basement subsidence, and faulting histories in the north and central basins of Lake Baikal aids in developing an interbasinal seismic stratigraphy that reveals the early synrift evolution of the central portion of the Baikal rift, a major continental rift system. Although there is evidence that the central and northern rift basins evolved at approximately the same time, their sedimentation histories are markedly different. Primary sediment sources for the initial rift phase were from the east flank of the rift; two major deltas developed adjacent to the central basin: the Selenga delta at the south end and the Barguzin delta at the north end. The Barguzin River system, located at the accommodation zone between the central and north basins, also fed into the southern part of the north basin and facilitated the stratigraphic linkage of the two basins. A shift in the regional tectonic environment in the mid Pliocene(?) created a second rift phase distinguished by more rapid subsidence and sediment accumulation in the north basin and by increased subsidence and extensive faulting in the central basin. The Barguzin delta ceased formation and parts of the old delta system were isolated within the north basin and on Academic Ridge. These isolated deltaic deposits provide a model for the development of hydrocarbon plays within ancient rift systems. In this second tectonic phase, the dominant sediment fill in the deeper and more rapidly subsiding north basin shifted from the flexural (eastern) margin to axial transport from the Upper Angara River at the north end of the basin.

  18. 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.

  19. 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.

  20. 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.

  1. 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) ...

  2. 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

  3. 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

  4. 3-D Evolutionary model of the oblique rift basins-the study of Central African Rifts

    NASA Astrophysics Data System (ADS)

    Cheng, I. W.; Yang, K. M.; Wu, J. C.; Hsiuan, T. H.

    2015-12-01

    Because of their tectonostratigraphically high potentials to yield oil and gas, oblique rift basins are a noteworthy type of global petroleum basins. The main purpose of this study is to investigate characteristics of the structural style and basin evolution of the Central Africa rift subsystem (CAS). Establishing the evolutionary model of CAS by the analyses of tectonostratigraphy, geometry, kinematics of structural features and Particle Flow Code 3-Dimensions (PFC 3D). The results can be references for petroleum basin exploration. The study areas are in the CAS, including the Doba, Doseo and Salamat Basins. Basins are separated by a large-scale strike-slip fault zone (Borogop fault zone) across the CAS. The results showed that the Borogop fault zone pass through the CAS until the Late Cretaceous compression and then became a big-scaled strike-slip fault. The structural geometry of oblique rift is changed with the α angle between the rift trend and trend of tensile stress. PFC-3D indicated that 1) The α of the Doba, Doseo and Salamat Basins are 60°, 60° and 75°, respectively; 2) When the α got close to 45°, the density of the echelon faults alone the basin center decreased gradually; 3) The Doba Basin is wide and shallow which should be affected by meso-scaled stresses. The Doseo and Salamat Basins are narrow and deeper which should be affected by mega-scaled stresses. According to the abovementioned results, we suggest that 1) The Borogop fault zone had less influence on basin architecture of CAS, therefore the basins of CAS are not the pull-apart basins but the extensional basins, and 2) Doba and Doseo-Salamat Basins should probably belong to different type of petroleum systems, which have different scales of stress.

  5. 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.

  6. Origin of the Permian-Triassic Iberian Basin, central-eastern Spain

    NASA Astrophysics Data System (ADS)

    Arche, Alfredo; López-Gómez, José

    1996-12-01

    The Iberian Basin was an intracratonic rift basin in central-eastern Spain developed since Early Permian times. The basin boundary faults were normal, listric faults controlling an asymmetric extension propagating northeast with time. Hercynian or older lineaments controlled the orientation of the Iberian Basin and extension was accommodated basically in the hanging wall block by the formation of secondary grabens and a central high. The basin was related with the coeval Ebro, Catalan and Cuenca-Mancha Basins and their connections are discussed. Subsidence curves show that the Early Permian-Early Jurassic period of extension can be subdivided into three rifting episodes and a flexural one. Extension factor increases from 1.17 in the northwest to 1.29 near the Mediterranean coast. The increasing extension rate was accommodated by transfer faults trending NNE-SSW, more important in the Levante area. The rift evolution is intermittent and seems to reflect distinct stress fields. The collapse of the late Hercynian orogen and related increased heat flux, extension and rifting is the most probable origin of the Iberian Basin and related basins. The origin of the Catalan and the Valencia-Prebetic Basins is related to the southwards migration of the Hesse-Burgundy Rift along the eastern margin of the Iberian Microplate.

  7. Basin-level habitat characteristics of selected streams in central Nebraska

    USGS Publications Warehouse

    Zelt, R.B.

    1996-01-01

    The goal of stream habitat characterization is to use identified relations between habitat and other physical, chemical, or biological factors in interpreting water-quality conditions. Basin-level characterization of habitat is one component of the spatially hiearchial approach to stream habitat description adopted by the U.S. Geological Survey's National Water-Quality Assessment Program. The Central Nebraska Basins study unit is about 78,000 km2 in area and includes the Loup and Elkhorn River Basins as well as basins of smaller tributaries to the Platte River. Stream-basin habitat characteristics associated with nine fixed-sampling stations were computed from conventional and digital map data. Geographic information systems software was the principal analytical tool used. Basin characterizations generally were limited to only that part of each stream basin contained within the study unit. Habitat characteristics analyzed included basin size and shape, elevation, relief, drainage network characteristics, geology, physiography, soils, land use and cover, climate, runoff, and streamflow characteristics. The report presents a tabular summary of the basin-level habitat characteristics determined for the nine selected stream basins.

  8. 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

  9. Geothermal studies at Kirtland Air Force Base, Albuquerque, New Mexico

    SciTech Connect

    Riddle, L.; Grant, B.

    1981-05-01

    Due to an effort by government installations to discontinue use of natural gas, alternative energy sources are being investigated at Kirtland Air Force Base, Albuquerque, New Mexico. New Mexico has geologic characteristics favorable for geothermal energy utilization. Local heat flow and geochemical studies indicate a normal subsurface temperature regime. The alluvial deposits, however, extend to great depths where hot fluids, heated by the normal geothermal gradient, could be encountered. Two potential models for tapping geothermal energy are presented: the basin model and the fault model.

  10. 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.

  11. 2-D magnetotelluric inversion of the central part of Paraná Basin

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  12. Pleistocene structures and geomorphology in the southern and central Vienna Basin

    NASA Astrophysics Data System (ADS)

    Salcher, B.; Decker, K.; Meurers, B.; Hölzel, M.; Wagreich, M.

    2009-04-01

    The active Vienna Basin Transfer Fault system is related to the formation of several Pleistocene basins with depths of up to 170 m (e.g. Mitterndorf and Lassee Basin) and areas covering up to 270 km². Detailed fault and geometric information of these Pleistocene basin's as well as the impact of faulting on the recent geomorphology of the Vienna basin is very limited. Evidences are derived from sparse outcrop and geophysical data. Geophysical surveys covering the first 300 m below ground are limited to data from drillings and to data of few geoelectric measurements. In this study we present a technique using conventional Bouguer gravity data derived from hydrocarbon exploration surveys to obtain precise fault data and show the linkage between normal faults and geomorphology Different first order derivates of gravity data are used to precisely determine shallow fault locations. The obtained fault locations are validated against geophysical and geological data such as 2 D, 3 D seismic, geoelectric, drill log information and outcrop data. Using this technique a new and considerably more accurate model of Austria's largest Pleistocene Basin, the Mitterndorf Basin, was developed, demonstrating the kinematic (sinistral, pull apart basin) impact on the basin geometry and on fault activity during the Pleistocene. We also show the impact of Plio- to Pleistocene tectonics in a more regional framework, along the Danube in the southern and central Vienna Basin and the evolution of the Eisenstadt Basin at the transition to the Pannonian Basin. Results demonstrate the major impact of faults on landscape development. The precise constrain of near surface faults allowed to link diverse geomorphologic features to a tectonic origin such as scarps, grabens, valleys and erosional gullies. We suggest that this technique would be suitable for many continental basins where shallow lithological density contrasts do occur (i.e. marine to fluvial sediments).

  13. Petroleum geology of Cretaceous-Tertiary rift basins in Niger, Chad, and Central African Republic

    SciTech Connect

    Genik, G.J. )

    1993-08-01

    This overview of the petroleum geology of rift basins in Niger, Chad, and Central African Republic (CAR) is based on exploration work by Exxon and partners in the years 1969-1991. The work included 50,000 km of modern reflection seismic, 53 exploration wells, 1,000,000 km[sup 2] of aeromagnetic coverage, and about 10,500 km of gravity profiles. The results outline ten Cretaceous and Tertiary rift basins, which constitute a major part of the West and Central African rift system (WCARS). The rift basins derive from a multiphased geologic history dating from the Pan-African (approximately 750-550 Ma) to the Holocene. WCARS in the study area is divided into the West African rift subsystem (WAS) and the Central African rift subsystem (WAS) and the Central African rift subsystem (CAS). WAS basins in Niger and Chad are chiefly extensional, and are filled by up to 13,000 m of Lower Cretaceous to Holocene continental and marine clastics. The basins contain five oil (19-43[degrees]API) and two oil and gas accumulations in Upper Cretaceous and Eocene sandstone reservoirs. The hydrocarbons are sourced and sealed by Upper Cretaceous and Eocene marine and lacustrine shales. The most common structural styles and hydrocarbon traps usually are associated with normal fault blocks. CAS rift basins in Chad and CAR are extensional and transtensional, and are filled by up to 7500 m of chiefly Lower Cretaceous continental clastics. The basins contain eight oil (15-39[degrees]API) and one oil and gas discovery in Lower and Upper Cretaceous sandstone reservoirs. The hydrocarbons are sourced by Lower Cretaceous shales and sealed by interbedded lacustrine and flood-plain shales. Structural styles range from simple fault blocks through complex flower structures. The main hydrocarbon traps are in contractional anticlines. Geological conditions favor the discovery of potentially commercial volumes of oil in WCARS basins, of Niger, Chad and CAR. 108 refs., 24 figs., 4 tabs.

  14. 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.

  15. Structural Evolution of the Tuzgölü Basin in Central Anatolia, Turkey.

    PubMed

    Çemen; Göncüoglu; Dirik

    1999-11-01

    The Central Anatolian segment of the Alpine-Himalayan orogen contains "interior" basins, the largest of which is the Tuzgölü (Salt Lake) basin (>20,000 km2). It is bounded on the east by the Tuzgölü (Salt Lake) fault zone and on the west by the Yeniceoba and Cihanbeyli fault zones. Structural, stratigraphic, and sedimentologic evidence suggests that the Tuzgölü basin started as a fault-controlled basin during late Maastrichtian tectonism when the present-day northwest-trending faults that bound the basin were initiated. These faults may have been formed as normal faults suggesting extension or strike-slip faults with a normal component of movement indicating a large transtension at the time of their initiation. The late Maastrichtian faults were reactivated as strike-slip faults in response to late Eocene compression in the region that produced the Central Anatolian thrust belt to the north and the late Eocene south-dipping thrust faults of the Ulukisla basin to the south. This reactivation is suggested by structurally repeated and missing Paleocene-Eocene deposits in some of the basin's wildcat wells. The late Eocene regression in the Tuzgölü basin was caused by the combined effects of Eocene shortening and a large environmental change. Late Eocene evaporites suggest that the basin was dry before the start of the Neotectonic period, while during the Neotectonic itself the Tuzgölü fault zone was reactivated again, predominantly as a normal fault with a right-lateral strike-slip component. This is evidenced by (1) a major unconformity between the post-Eocene Koçhisar Formation of the Tuzgölü basin and the underlying Eocene rock units; (2) a well-developed rollover anticline observed on seismic reflection profiles; and (3) a right-step along the Tuzgölü fault zone seen in the field.

  16. Structure of the Anayet Permian basin (Axial Zone, Central Pyrenees)

    NASA Astrophysics Data System (ADS)

    Rodriguez, L.; Cuevas, J.; Tubía, J. M.

    2012-04-01

    The Anayet Permian basin was generated by strike-slip tectonics that opened subsident basins with pull-apart geometries in the western Spanish Axial Zone (between the Aragon and Tena valleys). A continental succession of Permian age, that represents the first post-variscan deposits in the area, fills the basin and covers discordantly Devonian to Carboniferous limestones, sandstones and slates. Permian deposits have been classically divided in four main detrital groups, with three basic volcanic episodes interbedded (Gisbert, 1984, Bixel, 1987): the Grey Unit (50-120 m, Estefanian to Kungurian) with slates, conglomerates, tobaceous slates, coal and pyroclastic deposits, the Transition Unit (50 m maximum) showing grey and red sandstones and lutites with oolitic limestones intercalated, the Lower Red Unit (250 m) composed of cross-bedded red sandstones and andesitic volcanic rocks at the top, and finally the Upper Red Unit (400 m minimum, top eroded) formed by three fining up megasequences of carbonates, red sandstones and lutites with lacustrine carbonates intercalated and alkali basalts at the top. Increasingly older rocks are found towards the western part of the basin, where its depocenter is located. South-vergent angular folds deform the Permian sedimentary succession. Fold axes are N115 °E-trending, almost horizontal and are characterized by a remarkably constant orientation. Folds exhibit a long limb dipping slightly to the north and a short vertical limb, occasionally reversed. In the Anayet basin four main folds, with a wavelength of 400 m, can be distinguished, two anticlines and two synclines, with minor folds associated. Related to the angular folds an axial plane foliation, E-trending and dipping 40 to 60° to the north, is developed in the lutites. The more competent rocks, conglomerates and breccias, only locally show a spaced fracture cleavage. No main thrusts have been detected in Permian rocks. However, minor scale decollements, usually low angle

  17. Paleoearthquakes and Eolian-dominated fault sedimentation along the Hubbell Spring fault zone near Albuquerque, New Mexico

    USGS Publications Warehouse

    Personius, S.F.; Mahan, S.A.

    2003-01-01

    The Hubbell Spring fault zone forms the modern eastern margin of the Rio Grande rift in the Albuquerque basin of north-central New Mexico. Knowledge of its seismic potential is important because the fault zone transects Kirtland Air Force Base/Sandia National Laboratories and underlies the southern Albuquerque metropolitan area. No earthquakes larger than ML 5.5 have been reported in the last 150 years in this region, so we excavated the first trench across this fault zone to determine its late Quaternary paleoseismic history. Our trench excavations revealed a complex, 16-m-wide fault zone overlain by four tapered blankets of mixed eolian sand and minor colluvium that we infer were deposited after four large-magnitude, surface-rupturing earthquakes. Although the first (oldest) rupture event is undated, we used luminescence (thermoluminescence and infrared-stimulated luminescence) ages to determine that the subsequent three rupture events occurred about 56 ?? 6, 29 ?? 3, and 12 ?? 1 ka. These ages yield recurrence intervals of 27 and 17 k.y. between events and an elapsed time of 12 k.y. since the latest surface-rupturing paleoearthquake. Slip rates are not well constrained, but our preferred average slip rate since rupture event 2 (post-56 ka) is 0.05 mm/yr, and interval slip rates between the last three events are 0.06 and 0.09 mm/yr, respectively. Vertical displacements of 1-2 m per event and probable rupture lengths of 34-43 km indicate probable paleoearthquake magnitudes (Ms or Mw) of 6.8-7.1. Future earthquakes of this size likely would cause strong ground motions in the Albuquerque metropolitan area.

  18. Facies analysis of strawn submarine fan complex, Fort Worth basin, central Texas

    SciTech Connect

    Pranter, M.J. )

    1990-02-01

    The Fort Worth basin is a Paleozoic foreland basin located in central Texas. The basin developed in direct response to the tectonic evolution of the Ouachita thrust belt. Fan delta, submarine fan, and related slope depositional systems comprising the lower Strawn Group were deposited within the Fort Worth foreland basin and platform and shelf-edge carbonates developed on the adjacent Concho platform. The Ouachita thrust belt and related structural highlands served as the principal source areas for the thick accumulation of lower Strawn submarine fan sequences. The nature and distribution of depositional environments were controlled by active subsidence within the Fort Worth basin. Both sediment loading and tectonic loading following thrust-sheet propagation were major contributors to basin subsidence. The most rapid subsidence within the Fort Worth basin occurred during the early and late Atokan and continued into the early Desmoinesian. Decreasing subsidence and sedimentation rates during the late Desmoinesian and early Missourian established a setting for the development of upper Strawn fluvial and deltaic systems, which eventually prograded across the Fort Worth basin. Several cycles of fan progradation and abandonment are represented within the lower Strawn. The lower Strawn delta-fed submarine fan turbidites were deposited at the base of the slope forming an aggrading ramplike depositional feature. Individual facies recognized in outcrop and within the subsurface include fan delta, prodelta slope, proximal ramp, and distal ramp facies. Sandstone geometries and sediment distribution patterns reflect this ramplike feature.

  19. Aeromagnetic anomalies uncover the Precambrian basement in the Chhattisgarh basin area, Central India

    NASA Astrophysics Data System (ADS)

    Ram, Bahadur; Singh, Nagendra; Murthy, A.

    2008-12-01

    This paper presents aeromagnetic images for the Chhattisgarh basin region, in Central India, to provide a new window on Precambrian basement geology and structure. On the basis of aeromagnetic patterns, the Chhattisgarh basin is sub-divided into a northern low (negative) anomaly zone and a southern high (positive) anomaly zone. The northern portion of the main Chhattisgarh basin has been further divided into two subbasins, the Hirri sub-basin in the west, and Baradwar sub-basin in the east. A prominent negative anomaly delineates a NW-SE trending greenstone belt separating these sub-basins. Positive magnetic anomalies delineate the extent of the Dongargarh granite and equivalents, while the weak magnetic anomaly in the southeast of the Dongargarh granite and equivalents reflect granulite gneisses of the Eastern Ghat Mobile Belt. By applying the reduced-to-the-equator filter we enhanced the possible magnetic sources and structural lineaments within the Chhattisgarh basin. A new sketch map of structural elements was then compiled from aeromagnetic interpretation over the Chhattisgarh basin area. It includes possible faults, folds and an inferred lithological boundary.

  20. 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.

  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. 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.

  3. Late quaternary sediment sources, storage and transfers within mountain basins using clast lithological analysis: Pineta Basin, central Pyrenees, Spain

    NASA Astrophysics Data System (ADS)

    Jones, A. P.

    2000-09-01

    Understanding basin-wide sediment dynamics, both spatially and temporally, is an important antecedent to eventual quantitative interpretation of sediment transfer within mountain fluvial systems. This paper describes an attempt to trace sediment transfer modes and pathways using clast lithological analysis in a small mountain basin strongly influenced by glaciation: the Pineta Basin in the central Pyrenees of Spain. The paper interprets slope-channel interaction by encompassing the whole basin, enabling staged sedimentary pathways to be revealed. Additionally, bed-material textures of the modern rivers and youngest La Sarra Terrace were investigated to provide further information on the geomorphic coupling of the system. Relatively few studies have taken this approach. Glacial and later, fluvial systems transferred the sediments creating laterally extensive, polylithological sediment stores. Local depositional systems overprint this inherited signature. To what extent depends on the size and energy of the local system. Significant impacts are made by conduits, such as large-scale fluvially dominated fans and waterfalls, which deliver local lithologies to the main river. Conduits may be part of the main river system or part of the tributary system. Conduits are the most important elements when considering provenance studies and theoretical modelling.

  4. Spatial and temporal variability of water productivity in the Syr Darya Basin, central Asia

    NASA Astrophysics Data System (ADS)

    Abdullaev, Iskandar; Molden, David

    2004-08-01

    Application of water productivity analysis can provide clues in the search for solutions to solve water management problems of central Asia. It is in this context that this paper provides an analysis of water productivity both spatially and temporally in the cotton and rice production areas of Syr Darya Basin of central Asia. The spatial analysis includes different farm types and basin segments, and the temporal analysis includes 3 hydrological years during 1999-2001. The analysis of temporal data showed that in water-deficient years, water productivity, both in terms of supply and evapotranspiration, is higher than the same in water-abundant years. The data also show that type and size of farms have an impact on water productivity in the case of both cotton and rice. This study concludes by suggesting strategies and options for enhancing the average water productivity both in the cotton- and rice-growing areas of the Syr Darya Basin.

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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.

    2015-11-12

    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.

  10. 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.

  11. 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.

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

    USGS Publications Warehouse

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

    2015-01-01

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

  13. 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.

  14. Geologic framework for the coal-bearing rocks of the Central Appalachian Basin

    USGS Publications Warehouse

    Chesnut, D.R.

    1996-01-01

    Coal production has been an important economic factor in the Central Appalachian Basin. However, regional stratigraphic and structural relationships of the coal-bearing rocks of the basin have been poorly understood due to numerous separate nomenclatural schemes employed by various states. In order to estimate coal resources and understand mechanisms controlling the distribution of coal within the basin, a reliable geologic framework is necessary. Seven detailed cross sections across the Central Appalachian Basin were constructed in order to examine the stratigraphic and structural framework of the coal-bearing rocks in the basin. The cross sections were based on more than 1000 oil and gas well logs, measured sections, and borehole information from Kentucky, Ohio, Tennessee, Virginia and West Virginia. The cross sections revealed three main points discussed here: southeast thickening of the Pennsylvanian strata, unconformable northwestward onlapping relationship of Lower Pennsylvanian strata over underlying Lower Pennsylvanian and Mississippian strata and regional continuity of beds. The cross sections, geologic mapping, coal-resource studies, extensive new highway exposures and the occurrence of tonstein beds indicate that many coal beds and marine strata are laterally extensive, albeit locally variable across the basin. Certain quartzose sandstone bodies are also extensive over large areas of the basin. Existing stratigraphic nomenclature schemes obscured the geologic framework of the basin, so a new unified nomenclature scheme was devised to better describe stratigraphic features of the basin. The new stratigraphic nomenclature, now only formalized for Kentucky, was based on key stratigraphic units that proved to be extensive across the basin. Lower and Middle Pennsylvanian rocks are now recognized as the Breathitt Group (the Breathitt Formation was elevated to group rank). The Breathitt Group was subdivided into eight coal-bearing formations by relatively thick

  15. Maps showing sedimentary basins, surface thermal maturity, and indications of petroleum in the Central Alaska Province

    USGS Publications Warehouse

    Troutman, Sandra M.; Stanley, Richard G.

    2003-01-01

    This publication includes two maps (at 1:2,500,000 scale) and a pamphlet that describe sedimentary basins, surface thermal maturity, and 95 reported occurrences of petroleum in natural seeps, wells, and rock outcrops in central Alaska. No commercial petroleum production has been obtained from central Alaska, in contrast to the prolific deposits of oil and gas that have been found and developed in northern Alaska and the Cook Inlet region. Nevertheless, confirmed indications of petroleum in central Alaska include (1) natural seeps of methane gas on the Yukon Delta; (2) occurrences of methane gas in wells in the Bethel, Kotzebue, Nenana, Northway, and Yukon Flats basins; (3) oil and methane gas in seeps and wells in Norton Sound; (4) small quantities of liquid and solid hydrocarbons associated with mercury ore in the Kuskokwim Mountains; (5) oil shale and numerous occurrences of bitumen in the Kandik area; and (6) tasmanite, a form of oil shale, in the uplands north of Yukon Flats.

  16. 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.

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

    USGS Publications Warehouse

    Gellenbeck, Dorinda J.; Coes, Alissa L.

    1999-01-01

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

  18. 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.

  19. 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.

  20. Structural Evolution of the Tuzgölü Basin in Central Anatolia, Turkey.

    PubMed

    Çemen; Göncüoglu; Dirik

    1999-11-01

    The Central Anatolian segment of the Alpine-Himalayan orogen contains "interior" basins, the largest of which is the Tuzgölü (Salt Lake) basin (>20,000 km2). It is bounded on the east by the Tuzgölü (Salt Lake) fault zone and on the west by the Yeniceoba and Cihanbeyli fault zones. Structural, stratigraphic, and sedimentologic evidence suggests that the Tuzgölü basin started as a fault-controlled basin during late Maastrichtian tectonism when the present-day northwest-trending faults that bound the basin were initiated. These faults may have been formed as normal faults suggesting extension or strike-slip faults with a normal component of movement indicating a large transtension at the time of their initiation. The late Maastrichtian faults were reactivated as strike-slip faults in response to late Eocene compression in the region that produced the Central Anatolian thrust belt to the north and the late Eocene south-dipping thrust faults of the Ulukisla basin to the south. This reactivation is suggested by structurally repeated and missing Paleocene-Eocene deposits in some of the basin's wildcat wells. The late Eocene regression in the Tuzgölü basin was caused by the combined effects of Eocene shortening and a large environmental change. Late Eocene evaporites suggest that the basin was dry before the start of the Neotectonic period, while during the Neotectonic itself the Tuzgölü fault zone was reactivated again, predominantly as a normal fault with a right-lateral strike-slip component. This is evidenced by (1) a major unconformity between the post-Eocene Koçhisar Formation of the Tuzgölü basin and the underlying Eocene rock units; (2) a well-developed rollover anticline observed on seismic reflection profiles; and (3) a right-step along the Tuzgölü fault zone seen in the field. PMID:10517884

  1. A transtensional basin model for the Organyà basin (central southern Pyrenees) based on magnetic fabric and brittle structures

    NASA Astrophysics Data System (ADS)

    Oliva-Urcia, B.; Casas, A. M.; Soto, R.; Villalaín, J. J.; Kodama, K.

    2011-01-01

    The purpose of this paper is to explain the kinematics of the inverted extensional Organyà basin (Central Southern Pyrenees) during its extensional evolution. The study of the anisotropy of magnetic susceptibility (AMS) and the study of brittle mesostructures are the instruments used to decipher the extensional kinematics. Separation of magnetic subfabrics (analyses of AMS at low temperature and anisotropy of the anhysteretic remanence - AARM) has been also done to properly interpret the obtained magnetic fabric data. The combination of all magnetic fabric and brittle mesostructures analyses has provided new information to clarify the structural evolution of the basin, which support a new tectonic model for the Aptian-Albian basinal stage. 20 sites for the magnetic fabric analysis were sampled in Aptian-Lower Albian marls. The AMS ellipsoids obtained at room temperature show their kmin axes perpendicular to bedding and kmax axes oriented NW-SE in 70 per cent of the samples, N-S in 15 per cent and NE-SW in 15 per cent. Analyses of AMS at low temperature show a better clustering of the axes of the magnetic ellipsoid pointing out that phyllosilicates constitute the carriers of the AMS, whereas the analyses of the AARM confirm the scattering of the ferromagnetic grains. These results suggest that the obtained AMS in the Organyà basin was acquired during or shortly after deposition of the Aptian-Lower Albian marls without any subsequent overprint. The direction of the magnetic lineation obtained from the AMS at room and low temperatures, agrees with the orientation of the stress axes obtained from the analysis of brittle mesostructures (mainly faults and calcite-filled tension gashes) indicating its tectonic origin. We interpret the orientation of the magnetic ellipsoids related to the transtensional movements linked to the formation of the Organyà basin during the Aptian-Albian interval, which are consistent with the eastward displacement and rotation of Iberia with

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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...

  9. Flood of June 4-5, 2002, in the Maquoketa River Basin, east-central Iowa

    USGS Publications Warehouse

    Eash, David A.

    2004-01-01

    Severe flooding occurred on June 4-5, 2002, in the Maquoketa River Basin in Delaware, Dubuque, Jackson, and Jones Counties, following thunderstorm activity over east-central Iowa. The rain gage at Cascade, Iowa, recorded a 14-hour rainfall of 6.0 inches at noon on June 4. Radar indications estimated as much as 8 to 10 inches of rain fell in the upper-middle part of the Maquoketa River Basin. Peak discharges on the Maquoketa River at Monticello of 47,500 cubic feet per second (recurrence interval estimated to be greater than 500 years as computed using flood-estimation equations developed by the U.S. Geological Survey), and at the Maquoketa River near Maquoketa streamflow-gaging station of 47,900 cubic feet per second (recurrence interval about 50 years), were determined for the flood. The peak discharge of the 2002 flood is nearly equal that of the 1944 flood (48,000 cubic feet per second), the largest flood on record in the Maquoketa River Basin. The 2002 flood is the largest known flood in the North Fork Maquoketa River Basin. A peak discharge of 22,600 cubic feet per second (recurrence interval about 110 years) was determined for the flood at the North Fork Maquoketa River near Fulton gaging station. Information about the basin and flood history, the 2002 thunderstorms and associated flooding, and a profile of high-water marks are presented for selected reaches along the Maquoketa and North Fork Maquoketa Rivers.

  10. 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

  11. 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

  12. 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.

  13. Flood of August 31-September 1, 1978, in Crosswicks Creek basin and vicinity, central New Jersey

    USGS Publications Warehouse

    Vickers, Arthur A.

    1980-01-01

    A thunderstorm during the evening of August 31, 1978, caused flooding in a small area of south central New Jersey. Maximum peaks of record occurred on the upper Crosswicks Creek basin in the vicinity of Fort Dix, Wrightstown, and New Egypt. At New Egypt, high water crest elevations for Crosswicks Creek were approximately 4 feet higher than the previous maximum recorded on August 28, 1971. Total damages were in excess of 2 million dollars, with 70 houses and 14 businesses affected.

  14. Salt as a 3D element in structural modelling - example from the Central European Basin System

    NASA Astrophysics Data System (ADS)

    Maystrenko, Y. P.; Scheck-Wenderoth, M.; Bayer, U.

    2010-12-01

    The Central European Basin System (CEBS) covers the northern part of Central and Western Europe and contains up to 12 km of Permian to Cenozoic deposits. Initiated in the Early Permian, the Central European Basin System accumulated Lower Permian clastics overlain by significant amount of Upper Permian (Zechstein) salt. Post-Permian differentiation of the basin system was controlled by several phases of tectonic activity. These tectonic phases not only provoked regional shifts in subsidence and erosion but also triggered movements of the Upper Permian (Zechstein) salt. Salt rise strongly influenced the Meso-Cenozoic structural evolution in terms of mechanical decoupling of the sedimentary cover from its basement. As a result of several phases of salt tectonics, the CEBS displays a wide variety of salt structures (walls, diapirs and pillows). In order to investigate the interaction of salt movements, deposition and tectonics, the 3D structural model of the CEBS has been constructed covering the entire salt basin (Northern and Southern Permian basins). Seismic interpretation and 3D backstripping have been used to investigate both the present-day structure and the evolution of the CEBS. 3D backstripping includes 3D salt redistribution in response to the changing load conditions in the salt cover. The results of 3D modelling of salt movements and seismic data indicate that the primary initiation of salt movements occurred during the Triassic. The Triassic regional extensional event initiated a phase of salt movements within the coeval depocenters of the CEBS, such as the Glueckstadt Graben, the Horn Graben, the Fjerritslev Trough and the adjacent Himmerland Graben in Denmark, as well as the Polish Basin. The Early Triassic (Buntsandstein) and the Late Triassic (Middle-Late Keuper) extensional events triggered strongest salt movements within the central part of the Glueckstadt Graben. During the Late Jurassic-Early Cretaceous, major erosion regionally truncated the study

  15. 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.

  16. Escape from Albuquerque: An Apache Memorate.

    ERIC Educational Resources Information Center

    Greenfeld, Philip J.

    2001-01-01

    Clarence Hawkins, a White Mountain Apache, escaped from the Albuquerque Indian School around 1920. His 300-mile trip home, made with two other boys, exemplifies the reaction of many Indian youths to the American government's plans for cultural assimilation. The tale is told in the form of traditional Apache narrative. (TD)

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Water use and availability in the Woonasquatucket and Moshassuck River basins, north-central Rhode Island

    USGS Publications Warehouse

    Nimiroski, Mark T.; Wild, Emily C.

    2005-01-01

    The Woonasquatucket River Basin includes 51.0 square miles, and the Moshassuck River Basin includes 23.8 square miles in north-central Rhode Island. The study area comprises these two basins. The two basins border each other with the Moshassuck River Basin to the northeast of the Woonasquatucket River Basin. Seven towns are in the Woonasquatucket River Basin, and six towns are in the Moshassuck River Basin. To determine the water use and availability in the study area, water supply and discharge data were collected for these river basins for the 1995–99 period, and compared to estimated long-term water available. The study area is unique in the State of Rhode Island, because no withdrawals from major public suppliers were made during the study period. Withdrawals were, therefore, limited to self-supplied domestic use, two minor suppliers, and one self-supplied industrial user. Because no metered data were available, the summer water withdrawals were assumed to be the same as the estimates for the rest of the year. Seven major water suppliers distribute an average of 17.564 million gallons per day for use in the study area from sources outside of the study area. The withdrawals from minor water suppliers were 0.017 million gallons per day in the study area, all in the town of Smithfield in the Woonasquatucket River Basin. The remaining withdrawals in the study area were estimated to be 0.731 million gallons per day by self-supplied domestic, commercial, industrial, and agricultural users. Return flows in the study area included self-disposed water and disposal from permitted dischargers, including the Smithfield Sewage Treatment Plant. Return flows accounted for 4.116 million gallons per day in the study area. Most public-disposed water (15.195 million gallons per day) is collected by the Narragansett Bay Commission and is disposed outside of the basin in Narragansett Bay. The PART program, a computerized hydrograph-separation application, was used at one index

  2. Late Cretaceous to recent tectonic evolution of the Ulukisla Basin (Southern Central Anatolia)

    NASA Astrophysics Data System (ADS)

    Gürer, Derya; van Hinsbergen, Douwe; Matenco, Liviu; Kaymakci, Nuretdin; Corfu, Fernando

    2014-05-01

    Anatolia is located in a complex zone resulting from the collision and subduction of several continental fragments previously separated by strands of the Neotethys Ocean. Around 90 Ma ago the geology of Turkey exhibited (arguably at least) two subduction zones: one dipping below the Pontides in the North, and one dipping below oceanic lithosphere, now found as ophiolites, to the south of the Pontides. Subsequent subduction led to the accretion of (parts of) the following terranes (from N-S and old to young): the Central Anatolian Crystalline complex (85 Ma); the HP-LT Tavsanli (80-75 Ma) and Afyon (70-65 Ma) belts; and the essentially non-metamorphic Tauride fold and thrust belt (Paleocene-Eocene). In Central Turkey, continental rocks arrived earliest in the subduction zone below the ophiolites and now form the Central Anatolian Crystalline Complex (CACC). To the east, however, the continental passive margin was farther to the south and there is no evidence that continental rocks arrived in the southern subduction zone before the Late Cretaceous (~70-65 Ma). Overlying these accretionary wedges and ophiolites are sedimentary basins, which potentially form a geological archive of the subduction and collision history of the region. The Late Cretaceous to early Tertiary Ulukisla basin is straddling and sandwiched between the CACC in the north and the Taurides in the south. Our results show that the lower part of the infill was deposited in an E-W extensional basin expressed by large-displacement, listric normal faults. This extension direction was widespread during the late Cretaceous to Paleocene of the CACC, as shown by extensional detachments and sedimentary basins. Subsequently, the infill was folded by N-S compression, thrusted northwards by a back-thrust that cuts the south-vergent Tauride fold-thrust belt, and transported northwards. Compression likely occurred during the deposition of a sequence of continental redbeds and lacustrine sediments found in the

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Laramide structure of the central Sangre de Cristo Mountains and adjacent Raton Basin, southern Colorado

    USGS Publications Warehouse

    Lindsey, D.A.

    1998-01-01

    Laramide structure of the central Sangre de Cristo Mountains (Culebra Range) is interpreted as a system of west-dipping, basement-involved thrusts and reverse faults. The Culebra thrust is the dominant structure in the central part of the range; it dips 30 -55?? west and brings Precambrian metamorphic base-ment rocks over unmetamorphosed Paleozoic rocks. East of the Culebra thrust, thrusts and reverse faults break the basement and overlying cover rocks into north-trending fault blocks; these boundary faults probably dip 40-60?? westward. The orientation of fault slickensides indicates oblique (northeast) slip on the Culebra thrust and dip-slip (ranging from eastward to northward) movement on adjacent faults. In sedimentary cover rocks, east-vergent anticlines overlie and merge with thrusts and reverse faults; these anticlines are interpreted as fault-propagation folds. Minor east-dipping thrusts and reverse faults (backthrusts) occur in both the hanging walls and footwalls of thrusts. The easternmost faults and folds of the Culebra Range form a continuous structural boundary between the Laramide Sangre de Cristo highland and the Raton Basin. Boundary structures consist of west-dipping frontal thrusts flanked on the basinward side by poorly exposed, east-dipping backthrusts. The backthrusts are interpreted to overlie structural wedges that have been emplaced above blind thrusts in the basin margin. West-dipping frontal thrusts and blind thrusts are interpreted to involve basement, but backthrusts are rooted in basin-margin cover rocks. At shallow structural levels where erosion has not exposed a frontal thrust, the structural boundary of the basin is represented by an anticline or monocline. Based on both regional and local stratigraphic evidence, Laramide deformation in the Culebra Range and accompanying synorogenic sedimentation in the western Raton Basin probably took place from latest Cretaceous through early Eocene time. The earliest evidence of uplift and

  9. Sequence stratigraphy and evolution of the Antler foreland basin, east-central Nevada

    SciTech Connect

    Trexler, J.H. Jr.; Nitchman, S.P. )

    1990-05-01

    The Mississippian Antler foreland basin contains siliciclastic sedimentary rocks that record a series of orogenic events along the western margin of North America from about 350 to 320 Ma. Our new stratigraphic and sedimentologic studies in Nevada indicate that the strata are not generally progradiational as previously described, and that uplift played a large role in basin evolution. We have recognized three unconformity-bounded stratigraphic sequences in the Antler basin in central Nevada: the Diamond Range submarine-fan system, the Newark Valley fluvial and delta-plain system, and the Green Springs deltaic and shelf-carbonate system. They propose a two-phase history for the antler orogeny: (1) collision of the western edge of North America with the Antler allochthon and downwarping of the continental margin (360-350 Ma), which resulted in deposition of the Diamond Range submarine-fan system; and (2) uplift and low-amplitude folding of the basin (350-320 Ma), accompanied by deposition of a thin veneer of reworked siliciclastic sediments (Newark Valley and Green Springs sequences) across a shallow-marine shelf. Siliciclastic sedimentation waned in the Late Mississippian and Early Pennsylvanian, and gradually gave way to carbonate sedimentation.

  10. 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.

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

    USGS Publications Warehouse

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

    1980-01-01

    The Payette River basin, characterized by steep, rugged mountains and narrow river valleys, occupies an area of about 3 ,300 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 to 86 degrees Celsius, are sodium bicarbonate types and are slightly alkaline. Dissolved-solids concentrations range from 173 to 470 milligrams per liter. Reservoir temperatures determined from the sodium-potassium-calcium and silicic acid-corrected silica geothermometers range from 53 to 143 degrees Celsius. Tritium, present in concentrations between 0 and 2 tritium units, indicate sampled thermal waters are at least 100 years old and possibly more than 1,000 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 5,700 acre-feet of water in 1979. Associated convective heat flux is 1.1x10 to the 7th power calories per second. (USGS)

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

    USGS Publications Warehouse

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

    1982-01-01

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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Conventional tree height-diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin.

    PubMed

    Kearsley, Elizabeth; de Haulleville, Thales; Hufkens, Koen; Kidimbu, Alidé; Toirambe, Benjamin; Baert, Geert; Huygens, Dries; Kebede, Yodit; Defourny, Pierre; Bogaert, Jan; Beeckman, Hans; Steppe, Kathy; Boeckx, Pascal; Verbeeck, Hans

    2013-01-01

    Policies to reduce emissions from deforestation and forest degradation largely depend on accurate estimates of tropical forest carbon stocks. Here we present the first field-based carbon stock data for the Central Congo Basin in Yangambi, Democratic Republic of Congo. We find an average aboveground carbon stock of 162 ± 20  Mg  C  ha(-1) for intact old-growth forest, which is significantly lower than stocks recorded in the outer regions of the Congo Basin. The best available tree height-diameter relationships derived for Central Africa do not render accurate canopy height estimates for our study area. Aboveground carbon stocks would be overestimated by 24% if these inaccurate relationships were used. The studied forests have a lower stature compared with forests in the outer regions of the basin, which confirms remotely sensed patterns. Additionally, we find an average soil carbon stock of 111 ± 24  Mg  C  ha(-1), slightly influenced by the current land-use change.

  20. Conventional tree height-diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin

    NASA Astrophysics Data System (ADS)

    Kearsley, Elizabeth; Hufkens, Koen; Steppe, Kathy; Beeckman, Hans; Boeckx, Pascal; Verbeeck, Hans

    2014-05-01

    Accurate estimates of the amount of carbon stored in tropical forests represent crucial baseline data for recent climate change mitigation policies. Such data are needed to quantify possible emissions due to deforestation and forest degradation, and to evaluate the potential of these forests to act as carbon sinks. Currently, only rough estimates of the carbon stocks for Central African tropical forests are available due to a lack of field data, and little is known about the response of these stocks to climate change. We present the first field-based carbon stock data for the Central Congo Basin in Yangambi, Democratic Republic of Congo. We found an average aboveground carbon stock of 162 ± 20 Mg C ha-1 for intact old-growth forest, which is significantly lower than stocks recorded in the outer regions of the Congo Basin. The best available tree height-diameter relationships derived for Central Africa do not render accurate canopy height estimates for our study area. Aboveground carbon stocks would be overestimated by 24% if these inaccurate relationships were used. The studied forests have a lower stature compared with forests in the outer regions of the basin, which confirms remotely sensed patterns. We identified a significant difference in height-diameter relations across the Congo Basin as a driver for spatial differences in carbon stocks. The study of a more detailed interaction of the environment and the available tree species pool as drivers for differences in carbon storage could have large implications. The effect of the species pool on carbon storage can be large since species differ in their ability to sequester carbon, and the collective functional characteristics of plant communities could be a major driver of carbon accumulation. Numerous species-specific tree height-diameter relations are established for two sites around Kisangani, central Congo Basin, with differing stand height-diameter relationships. The species-specific relations for the two

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

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

    USGS Publications Warehouse

    Sanocki, C.A.

    1997-01-01

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

  10. Water quality in the central Arizona basins, Arizona, 1995-98

    USGS Publications Warehouse

    Cordy, Gail E.; Gellenbeck, Dorinda J.; Gebler, Joseph B.; Anning, David W.; Coes, Alissa L.; Edmonds, Robert J.; Rees, Julie A.H.; Sanger, H.W.

    2000-01-01

    The water quality in rivers and streams and in selected aquifers in central Arizona basins in Arizona is described and illustrated. Major ions, nitrogen and other nutrients, and pesticides and some of their breakdown compounds were analyzed in both surface and ground water. Biological communities that included fish, invertebrates, and algae, were described in relation to stream water quality. Volatile organic compounds that originate from fuels, solvents, and industry were analyzed from ground-water samples. Agricultural and urban land-use effects on shallow ground water are compared and contrasted.

  11. 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.

  12. 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...

  13. 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).

  14. Late Cretaceous-Paleogene deepwater basin of North Afghanistan and the Central Pamirs: Issue of Hindu Kush earthquakes

    NASA Astrophysics Data System (ADS)

    Kaz'min, V. G.; Lobkovsky, L. I.; Tikhonova, N. F.

    2010-03-01

    The within-Iranian backarc basins, including the largest Sebzawar Basin, opened in the Mid-Cretaceous. Spreading in this basin was completed by the end of the Cretaceous. The basin closed in the Eocene with the formation of subduction zones and volcanic-plutonic belts. Data on North Afghanistan and the Central Pamirs have allowed us to reconstruct the eastern continuation of the Sebzawar Basin up to the west of the Central Pamirs. No fragments of oceanic crust are retained in Afghanistan and the Pamirs, but by analogy with the Sebzawar Basin, thick Paleogene flysch sequences and volcanic-plutonic complexes indicate setting of the active margin and subduction. It is suggested that the belt of mantle seismicity that extends for 550 km to the south of the Central Pamirs is related to the plunging and deformation of the lithosphere once underlying the Cretaceous-Paleogene basin. The extremely vigorous seismicity of the Hindu Kush megasource at the western termination of the seismic belt is caused by a number of specific tectonic features that predetermined the early onset of plunging of the subducted sheet (slab). In the megasource, the slab sank to a depth of 300 km and became vertical; its active deformation has proceeded up to the present. In the eastern part of the seismic belt, the slab started to plunge much later and therefore has retained a gentle slope, so that the depth of the hypocenters is shallower (down to 200 km), and earthquakes are less strong.

  15. 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

  16. 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

  17. Sedimentology and diagenesis of a rift basin lacustrine sandstone: Pematang group, central Sumatra, Indonesia

    SciTech Connect

    Janks, J.S.; Kelley, P.A.; Williams, H.H.

    1986-05-01

    The Central Sumatra basin is a back-arc basin that formed during the Paleocene as a series of half-graben structures. These early formed half-graben structures were filled with nonmarine clastics and lacustrine sediments of the Pematang Group, sourced from local highland areas. The Pematang Group consists of the Lower Red Beds, Brown Shale, Coal Zone Member, and Lake Fill Formation (in ascending order). The Pematang Group sedimentology is intimately related to the regional and basinal tectonic development and history. Sandstones of the Pematang Group are predominantly sublitharenites and litharenites; feldspars are rare. Sandstone diagenesis is relatively uniform regardless of the depositional environment. Diagenetic modifications include compaction, early calcite and dolomite cementation, quartz overgrowth formation, unstable rock-fragment dissolution, kaolinite precipitation, siderite formation, and local illite formation. Secondary porosity accounts for up to 50% of the effective porosity and was created by rock-fragment dissolution. This dissolution is probably caused by the organic acids released during kerogen maturation. Stable isotope data from diagenetic siderite are presented.

  18. 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.

  19. 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.

  20. Postglacial response of a stream in central Iowa to changes in climate and Drainage basin factors

    USGS Publications Warehouse

    Van Nest, J.; 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. ?? 1990.

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

    USGS Publications Warehouse

    Gannett, Marshall W.; Lite, Kenneth E.

    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

  2. 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.

  3. Floods of November-December 1950 in the Central Valley basin, California

    USGS Publications Warehouse

    Paulsen, C.G.

    1953-01-01

    The flood of November-December 1950 in the Central Valley basin was the greatest in most parts of the basin since the turn of the century and probably was exceeded in the lower San Joaquin River basin only by the historic flood of 1862. In respect to monetary loss, the 1950 flood was the most disastrous in the history of the basin. Loss of life was remarkably small when one considers the extensive damage and destruction to homes and other property, which is estimated at 33 million dollars. Outstanding features of the flood were its unprecedented occurrence so early in the winter flood season, its magnitude in respect to both peak and volume in most major tributaries, and the occurrence of a succession of near-peak flows with a period of three weeks. The flood was caused by a series of storms during the period November 16 to December 8, which brought exceptionally warm, moisture-laden air inland against the Sierra Nevada range and caused intense rainfall, instead of snowfall, at unusually high altitudes. Basin-wide totals of rainfall during the period ranged from 30 inches over the Yuba and American River basins to 13 inches over the upper Sacramento and Feather River basins. Based on continuous records of discharge on major tributaries for periods ranging from 22 to 55 years and averaging about 43 years, the 1950 flood peaks were the greatest of record on the American, Cosumnes, Mokelumne, Stanislaus, Tuolumne, Merced, Chowchilla, Fresno, lower San Joaquin, Kings, Kaweah, Tule, and Kern Rivers. Second highest peak of record occurred during the flood of March 1928 on the Yuba, American and Mokelumne Rivers; the flood of Marcn 1940 on Cosumnes River; the flood of January 1911 on the Stanislaus and Tuolumne Rivers; the flood of December 1937 on the Merced, Kings, and Kaweah Rivers; the flood of March 1938 on the Chowchilla, Fresno, and lower San Joaquin Rivers; and the flood of March 1943 on the Tule and Kern Rivers. Peak discharges for 1950 did not exceed previous

  4. 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

  5. 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

  6. Characterization of petroleum reservoirs in the Eocene Green River Formation, Central Uinta Basin, Utah

    USGS Publications Warehouse

    Morgan, C.D.; Bereskin, S.R.

    2003-01-01

    The oil-productive Eocene Green River Formation in the central Uinta Basin of northeastern Utah is divided into five distinct intervals. In stratigraphically ascending order these are: 1) Uteland Butte, 2) Castle Peak, 3) Travis, 4) Monument Butte, and 5) Beluga. The reservoir in the Uteland Butte interval is mainly lacustrine limestone with rare bar sandstone beds, whereas the reservoirs in the other four intervals are mainly channel and lacustrine sandstone beds. The changing depositional environments of Paleocene-Eocene Lake Uinta controlled the characteristics of each interval and the reservoir rock contained within. The Uteland Butte consists of carbonate and rare, thin, shallow-lacustrine sandstone bars deposited during the initial rise of the lake. The Castle Peak interval was deposited during a time of numerous and rapid lake-level fluctuations, which developed a simple drainage pattern across the exposed shallow and gentle shelf with each fall and rise cycle. The Travis interval records a time of active tectonism that created a steeper slope and a pronounced shelf break where thick cut-and-fill valleys developed during lake-level falls and rises. The Monument Butte interval represents a return to a gentle, shallow shelf where channel deposits are stacked in a lowstand delta plain and amalgamated into the most extensive reservoir in the central Uinta Basin. The Beluga interval represents a time of major lake expansion with fewer, less pronounced lake-level falls, resulting in isolated single-storied channel and shallow-bar sandstone deposits.

  7. Late Pleistocene Major Sedimentary Reworking Event (Homogenite) in Marmara Sea Central Basin

    NASA Astrophysics Data System (ADS)

    Beck, C.; Schneider, J.-L.; Mercier de Lépinay, B.; Cagatay, N.; Labeyrie, L.; Wendenbaum, E.; Boutareau, S.; Ménot-Combes, G.; Hadjas, I.; Turon, J.-L.; Marmacore Scientific Party

    2003-04-01

    Among eight long piston-cores retrieved during MARMACORE Cruise, two were dedicated to the Marmara Sea Central Basin especially for paleoseismic purpose. There, very high-resolution profiles evidenced a main acoustically transparent unit ponded in the whole basin and resembling the so-called " homogenite " described in central-eastern Mediterranean and in deep lakes. Core MD01-2431 (26.4 m) crossed a major sedimentary event comprising three parts, from bottom to top : 0.7 m of mud clasts within coarse sand, 1.9 m of poorly-stratified sand, and 4.8 m of homogenous clayey silt (top at 15.2 m bsf). Two wood-fragments found in the homogenous horizon (60 cm-separated) yielded 17 100 yrs BP calibrated AMS C14 values. Textural investigation on involved sediments lead to consider the whole set as a unique reworking event with : mass waisting evolving into turbidite, basal liquefaction and erosion of in situ fine sediments, segregation by oscillation (seiche-like or constrained turbidite effect) of finer fraction. If admitting a triggering of the whole set by an earthquake comparable to the strongest historical ones, the unusual reworked volume of soft sediments could be explained by an occurrence during a period of particularly high terrigenous supply.

  8. 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.

  9. Basin and Range crustal and upper mantle structure, northwest to central Nevada

    SciTech Connect

    Catchings, R.D.; Mooney, W.D. )

    1991-04-10

    The authors present an interpretaton of the crustal and uppermost mantel structure of the Basin and Range of northwestern Nevada based on seismic refraction/wide-angle reflection, near-vertical reflection, and gravity data. In comparison to most previous estimates, they find that the crust is somehwat thicker (32-36 km versus 22-30 km), and the uppermost mantel velocity is somewhat higher (8.0 km/s versus 7.3-7.9 km/s). Variations in velocity and structure of the upper crustal layers reveal apparent basement velocity depressions that underlie some surface ranges as well as the basins. The middle crust rises from about 20 km beneath central Nevada to within 12 km of the surface beneath the area of thinnest crust and is characterized by a modest change in velocity and low-velocity gradients. These midcrustal layers mark the onset of high crustal reflectivity and the apparent limiting depth to which Basin and Range faults can be traced in near-vertical reflection profiles, suggesting that these midcrustal layers represent the transition between the brittle and ductile zones of the crust. The geometry of lower crustal layers (derived from refraction modeling) coincides with changes in the crustal reflectivity. Gravity modeling and comparison to existing seismic models show a general consensus in many aspects with respect to crustal structure. This new model forms the basis for speculation on some of the processes associated with rifting of the Basin and Range Province. One such process, lithospheric magmatism, is inferred from the strong attenuation of transmitted seismic waves, which occurs at the same interface at which high-amplitude, bright spot reflections originate. Unlike previous models, the overall structure and velocity of the crust and uppermost mantle of this model are similar to other regions worldwide which have undergone high degrees of extension.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

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

    USGS Publications Warehouse

    Knowles, Leel

    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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Subsurface geometry and growth history of the Warfield Structure in South-Central West Virginia, Central Appalachian basin

    SciTech Connect

    Gao, D.; Shumaker, R.C. )

    1994-08-01

    The Warfield structure is located at the eastern margin of Rome trough in south-central West Virginia, an intersection area between the 38th parallel and the Burning Springs lineaments in the central Appalachian basin. Using SURFACE III and MCS contouring packages, structure maps of upper Paleozoic horizons were completed by retrieving, editing, and contouring over 6000 shallow wells from the database of the DEAM (Data Editing and Management) software package. The Warfield anticline is horizontal at the Mississippian horizons, with a generally northeast-trending closure and a northwest-dipping axial plane, but at the Devonian level the closure is lost as the fold plunges northeastward. Structures from the Oriskany horizon to the basement were interpolated based on seismic and well data with a multisurface STACK procedure of the MCS package, and demonstrate a constrained half graben underneath the Warfield anticline with a 38th parallel and the north-south-trending Burning Springs lineaments. Based on preliminary results from subsurface mapping, digitization, and quantitative analysis of seismic time sections as well as computer modeling for the magnetic/gravity anomalies, the authors postulate that the geometry and growth history of the Warfield structure were genetically controlled by a wedge-shaped basement fault system in which the strike-slip displacement along both the eastwest-trending and the north-south-trending faults, and the dip-slip displacement on the northeast-trending faults occurred synchronously in response to the episodic movement of a wedge-shaped basement block bounded by the east-west-trending 38th parallel and the north-south-trending Burning Springs lineaments as well as the northeast-trending trough-margin faults throughout the Paleozoic.

  3. 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

  4. 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

  5. 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).

  6. The Albuquerque High School Moonwatch Team

    NASA Astrophysics Data System (ADS)

    Weisberg, Joel M.

    2007-12-01

    In the mid-1950s, a remarkable pair of high school teachers, Mrs. Vi Hefferan and (later) Mr. John Bartholdi, organized an astronomy club and Moonwatch satellite tracking team open to students from all Albuquerque high schools. The Albuquerque team distinguished itself as one of the best in the worldwide network. Among other tasks, they found some satellites that had been "lost" by professional trackers. The team provided a variety of interesting and exciting activities for science-interested students from the whole city. Among the most meaningful was the ability to make observations that were scientifically useful. By 1966 when I joined as a 10th grader, the excitement of the early days was gone but the sense of participation in a large and fascinating enterprise was still keen. I will discuss the techniques and technologies used to track satellites from the high school and from my front yard, including slide rules, rulers, telegrams, special delivery mail, short-wave radio time signals, tape recorders, stop watches, star maps, computers, and a five-inch rich-field "apogee" refractor. After a year of intense effort at satellite tracking for Moonwatch, I had the opportunity to visit a then-secret 48-inch Air Force satellite tracking telescope in southern NM in 1968. This event demonstrated the obsolescence of the amateur (though not amateurish!) techniques that we had been using and provided a fitting end to my participation as I left for college.

  7. 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.

  8. 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.

  9. 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.

  10. Late Devonian glacigenic and associated facies from the central Appalachian Basin, eastern United States

    USGS Publications Warehouse

    Brezinski, D.K.; Cecil, C.B.; Skema, V.W.

    2010-01-01

    Late Devonian strata in the eastern United States are generally considered as having been deposited under warm tropical conditions. However, a stratigraphically restricted Late Devonian succession of diamictite- mudstonesandstone within the Spechty Kopf and Rockwell Formations that extends for more than 400 km along depositional strike within the central Appalachian Basin may indicate other wise. This lithologic association unconformably overlies the Catskill Formation, where a 3- to 5-m-thick interval of deformed strata occurs immediately below the diamictite strata. The diamictite facies consists of several subfacies that are interpreted to be subglacial, englacial, supraglacial meltout, and resedimented deposits. The mudstone facies that overlies the diamictite consists of subfacies of chaotically bedded, clast-poor mudstone, and laminated mudstone sub facies that represent subaqueous proximal debris flows and distal glaciolacustrine rhythmites or varvites, respectively. The pebbly sandstone facies is interpreted as proglacial braided outwash deposits that both preceded glacial advance and followed glacial retreat. Both the tectonic and depositional frameworks suggest that the facies were deposited in a terrestrial setting within the Appalachian foreland basin during a single glacial advance and retreat. Regionally, areas that were not covered by ice were subject to increased rainfall as indicated by wet-climate paleosols. River systems eroded deeper channels in response to sea-level drop during glacial advance. Marine facies to the west contain iceborne dropstone boulders preserved within contemporaneous units of the Cleveland Shale Member of the Ohio Shale.The stratigraphic interval correlative with sea-level drop, climate change, and glacigenic succession represents one of the Appalachian Basin's most prolific oil-and gas-producing intervals and is contemporaneous with a global episode of sea-level drop responsible for the deposition of the Hangenberg Shale

  11. 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

  12. 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

  13. 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

  14. Hydrologic Setting and Conceptual Hydrologic Model of the Walker River Basin, West-Central Nevada

    USGS Publications Warehouse

    Lopes, Thomas J.; Allander, Kip K.

    2009-01-01

    The Walker River is the main source of inflow to Walker Lake, a closed-basin lake in west-central Nevada. Between 1882 and 2008, agricultural diversions resulted in a lake-level decline of more than 150 feet and storage loss of 7,400,000 acre-ft. Evaporative concentration increased dissolved solids from 2,500 to 17,000 milligrams per liter. The increase in salinity threatens the survival of the Lahontan cutthroat trout, a native species listed as threatened under the Endangered Species Act. This report describes the hydrologic setting of the Walker River basin and a conceptual hydrologic model of the relations among streams, groundwater, and Walker Lake with emphasis on the lower Walker River basin from Wabuska to Hawthorne, Nevada. The Walker River basin is about 3,950 square miles and straddles the California-Nevada border. Most streamflow originates as snowmelt in the Sierra Nevada. Spring runoff from the Sierra Nevada typically reaches its peak during late May to early June with as much as 2,800 cubic feet per second in the Walker River near Wabuska. Typically, 3 to 4 consecutive years of below average streamflow are followed by 1 or 2 years of average or above average streamflow. Mountain ranges are comprised of consolidated rocks with low hydraulic conductivities, but consolidated rocks transmit water where fractured. Unconsolidated sediments include fluvial deposits along the active channel of the Walker River, valley floors, alluvial slopes, and a playa. Sand and gravel deposited by the Walker River likely are discontinuous strata throughout the valley floor. Thick clay strata likely were deposited in Pleistocene Lake Lahontan and are horizontally continuous, except where strata have been eroded by the Walker River. At Walker Lake, sediments mostly are clay interbedded with alluvial slope, fluvial, and deltaic deposits along the lake margins. Coarse sediments form a multilayered, confined-aquifer system that could extend several miles from the shoreline

  15. 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.

  16. 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)

  17. Morrow fluvial and deltaic sandstones of Anadarko basin in southeastern and east-central Colorado

    SciTech Connect

    Patterson, E.; Cruthis, W.

    1985-05-01

    Paleozoic sediments in southeastern and east-central Colorado were deposited in the northwest portion of the Anadarko basin. The primary hydrocarbon reservoirs are fluvial and/or deltaic sandstones that represent late regressive cycles of Morrowan sedimentation in the Anadarko basin. The associated transgressive cycles resulted in deposition of marine shales above and below the sandstones. These shales are the source rock in which oil was generated. Morrowan point bars, bar fingers, and the Keyes Formation are productive in the study area along with 11 other formations, both younger and older. Deeper objectives, such as the Arbuckle Limestone and Misner Sandstone, have had limited penetrations and were mostly off-structure tests. The primary objectives of earlier wells in the area were the Mississippian reservoirs. Many of these wells were located on seismic highs or randomly drilled along the Las Animas arch. One reason that better oil production from Morrowan point bars was not found in earlier tests was a lack of understanding of the depositional history of the region. The primary objectives of current wells being drilled in the area are the numerous Morrowan point bars, which are located by stratigraphic seismic methods along with a thorough understanding of the geologic framework in the study area. The point bars have excellent reservoir qualities, with porosities ranging from 18 to 22% and permeabilities as high as 5500 md being reported. Point bars have been defined that cover over 3000 ac and can be penetrated above 6500 ft (1981 m).

  18. Physical characteristics of stream subbasins in the Pomme de Terre River Basin, west-central Minnesota

    USGS Publications Warehouse

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

    1994-01-01

    Data describing the physical characteristics of stream subbasins upstream from selected points on streams in the Pomme de Terre 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, outfalls of sewage treatment plants, and locations of U.S. Geological Survey low-flow, high-flow, and continuous-record gaging stations.

  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. 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.

  1. 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.

  2. 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

  3. 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.

  4. Long-lasting seismic repeaters in the Central Basin of the Main Marmara Fault

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, J.; Karabulut, H.; Lengliné, O.; Bouchon, M.

    2016-09-01

    The Main Marmara Fault which crosses the whole Marmara Sea is a significant seismic gap along the North Anatolian Fault. Here we show that nine long-lasting strike-slip seismic repeaters exist below the Central Basin within the seismogenic zone, in a 10 km region where deep creep was previously suggested from the analysis of the local seismicity. The typical recurrence time was 8 months during the 2008-2015 period. The cumulative slip of the repeating sequence appears to be compatible with the regional geodetic slip rate if they are assumed to be part of a large single asperity (10 km). The repeaters also exhibit short-term crises and are possibly related to bursts of creep.

  5. 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.

  6. Wet and dry nitrogen deposition in the central Sichuan Basin of China

    NASA Astrophysics Data System (ADS)

    Kuang, Fuhong; Liu, Xuejun; Zhu, Bo; Shen, Jianlin; Pan, Yuepeng; Su, Minmin; Goulding, Keith

    2016-10-01

    Reactive nitrogen (Nr) plays a key role in the atmospheric environment and its deposition has induced large negative impacts on ecosystem health and services. Five-year continuous in-situ monitoring of N deposition, including wet (total nitrogen (WTN), total dissolved nitrogen (WTDN), dissolved organic nitrogen (WDON), ammonium nitrogen (WAN) and nitrate nitrogen (WNN)) and dry (DNH3, DHNO3, DpNH4+, DpNO3- and DNO2) deposition, had been conducted since August 2008 to December 2013 (wet) and May 2011 to December 2013 (dry) in Yan-ting, China, a typical agricultural area in the central Sichuan Basin. Mean annual total N deposition from 2011 to 2013 was 30.8 kg N ha-1 yr-1, and speculated that of 2009 and 2010 was averaged 28.2 kg N ha-1 yr-1, respectively. Wet and dry N deposition accounted for 76.3% and 23.7% of annual N deposition, respectively. Reduced N (WAN, DNH3 and DpNH4+) was 1.7 times of oxidized N (WNN, DHNO3, DNO2 and DpNO3-) which accounted for 50.9% and 30.3% of TN, respectively. Maximum loadings of all N forms of wet deposition, gaseous NH3, HNO3 and particulate NH4+ in dry deposition occurred in summer and minimum loadings in winter. Whether monthly, seasonal or annual averaged, dissolved N accounted for more than 70% of the total. N deposition in the central Sichuan Basin increased during the sampling period, especially that of ammonium compounds, and has become a serious threat to local aquatic ecosystems, the surrounding forest and other natural or semi-natural ecosystems in the upper reaches of the Yangtze River.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. The Albuquerque City Center Schools. Program Evaluation, 1984-85.

    ERIC Educational Resources Information Center

    Johns, Jennifer S.; Panofsky, Carolyn

    The Albuquerque City Center Schools (ACCS) project, begun in 1983, was designed to increase the effectiveness of 12 schools in the Albuquerque High School cluster by creating a climate of high expectations, improving academic achievement, encouraging a climate of positive discipline, promoting student, community and private sector participation,…

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

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

    USGS Publications Warehouse

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

    1995-01-01

    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. The first model uses a traditional approach to quantify watershed hydrology through a precipitation-runoff modeling system that accounts for the spatial variability of hydrologic inputs, processes, and responses (outputs) using a dailycomputational time step. The second model is based on the conservative nature of the dissolved chloride ion in selected hydrologic environments, and its use as a natural tracer allows the computation of acoupled, water and chloride-ion, mass-balance system of equations to estimate available water (sum ofsurface runoff and groundwater recharge). 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. Evolution of the Southern San Joaquin Basin and mid-Tertiary "transitional" tectonics, central California

    NASA Astrophysics Data System (ADS)

    Goodman, Emery D.; Malin, Peter E.

    1992-06-01

    A Cenozoic tectonic and sedimentary history is proposed for the Southern San Joaquin Basin (SSJB) and Tehachapi Mountains that evolved adjacent to the plate margin off central California. Seismic reflection, borehole, field, biostratigraphic, and paleomagnetic data are integrated into geologic and fault structure maps, cross sections, and geohistory plots and are analyzed with previous work in the region to develop a model relating the sequence, timing, and distribution of complex, tectonically linked events. The largely buried structures and strata in the SSJB preserve an unusually complete record of the mid-Tertiary transition from convergent to transform plate boundary as well as the regional transition to contraction during the Pliocene. Significant structural relief, existing across both extensional and contractile features, is preserved in the subsurface and an active fold-thrust belt propagates basinward along the margin of the U-shaped Tejon embayment The Cenozoic evolution of the SSJB reflects the regional deformation of central California as different tectonic events followed each other along the adjacent North American plate margin. Five Oligocene-Miocene basin phases are identified in the SSJB: (1) late Oligocene/early Miocene extensional subsidence, with high- and low-angle normal faulting, accompanied by volcanism and deposition of coarse syntectonic conglomerates; (2) middle Miocene uplift; (3) later mid-Miocene transtensional subsidence to lower bathyal depths; (4) alternating subsidence and uplift until the late Miocene; and (5) flexural subsidence due to Pliocene to Recent contraction. Reconstructions of mid-Tertiary California place the southern San Joaquin/Tehachapi extensional terrane as a paleotectonic block located between the Western Mojave terrane (then to the east) and the Western California terrane (then to the south and west). Regional extension occurred during a long transition period between convergent and transform boundaries along

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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...

  15. 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...

  16. 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...

  17. Molecular markers in ambient aerosol in the Mahanadi Riverside Basin of eastern central India during winter.

    PubMed

    Nirmalkar, Jayant; Deb, Manas K; Deshmukh, Dhananjay K; Tsai, Ying I; Verma, Santosh K

    2015-01-01

    Organic molecular markers are important atmospheric constituents. Their formation and sources are important aspects of the study of urban and rural air quality. We collected PM10 aerosol samples from the Mahanadi Riverside Basin (MRB), a rural part of eastern central India, during the winter of 2011. PM10 aerosols were characterized for molecular markers using ion chromatography. The concentration of PM10 ranged from 208.8 to 588.3 μg m(-3) with a mean concentration of 388.9 μg m(-3). Total concentration of anhydrosugars, sugar alcohols, primary sugars, and oxalate were found to be 3.25, 5.60, 10.52, and 0.37 μg m(-3), respectively, during the study period. Glucose was the most abundant species followed by levoglucosan and mannitol. Significant positive correlation between the molecular markers, anhydrosugars, sugar alcohols, primary sugars, and oxalic acid confirmed that biomass burning, biogenic activity, and re-suspension of soil particles were the main sources of aerosol in the eastern central India study area. PMID:25131681

  18. 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.

  19. Monitoring and Modelling Glacier Melt and Runoff on Juncal Norte Glacier, Aconcagua River Basin, Central Chile

    NASA Astrophysics Data System (ADS)

    Pellicciotti, F.; Helbing, J. F.; Araos, J.; Favier, V.; Rivera, A.; Corripio, J.; Sicart, J. M.

    2006-12-01

    Results from a recent glacio-meteorological experiment on the Juncal Norte glacier, in central Chile, are presented. Melt water is a crucial resource in the Central Andes, as it provides drinking water, water for agriculture and for industrial uses. There is also increasing competition for water use and allocation, as water demands from mining and industry are rising. Assessing water availability in this region and its relation with climatic variations is therefore crucial. The Dry Central Andes are characterised by a climatic setting different from that of the Alps and the subtropical Andes of Bolivia and Peru. Summers are very dry and stable, with precipitation close to zero and low relative humidity. Solar radiation is very intense, and plays a key role in the energy balance of snow covers and glaciers. The main aim of this study is to investigate the glacier-climate interaction in this area, with particular attention devoted to advanced modelling techniques for the spatial redistribution of meteorological variables, in order to gain an accurate picture of the ablation processes typical of these latitudes. During the ablation season 2005/2006, an extensive field campaign was conducted on the Juncal Norte glacier, aimed at monitoring the melt and runoff generation processes on this remote glacier in the dry Andes. Melt rates, runoff at the snout, meteorological variables over and near the glacier, GPS data and glacier topography were recorded over the entire ablation season. Using this extensive and accurate data set, the spatial and temporal variability of the meteorological variables that drive the melt process on the glacier is investigated, together with the process of runoff generation. An energy balance model is used to simulate melt across the glacier, and special attention is devoted to the modelling of the solar radiation energy flux. The components of the energy balance are compared with those of Alpine basins. The validity of parameterisations of the

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. The Yukon Flats Cretaceous(?)-Tertiary Extensional Basin, East-Central Alaska: Burial and Thermal History Modeling

    USGS Publications Warehouse

    Rowan, Elisabeth L.; Stanley, Richard G.

    2008-01-01

    One-dimensional burial and thermal history modeling of the Yukon Flats basin, east-central Alaska, was conducted as part of an assessment of the region's undiscovered oil and gas resources. No deep exploratory wells have been drilled in the Yukon Flats region, and the subsurface geology of the basin is inferred from seismic reflection, gravity and magnetic surveys, and studies of shallow core holes in the basin and outcrops in the surrounding region. A thick sequence of Upper Cretaceous(?) and Cenozoic nonmarine sedimentary rocks is believed to fill the basin; coal and organic-rich mudstone and shale within this sequence represent potential hydrocarbon source rocks. The burial and thermal history models presented here represent the sole source of information on the thermal maturity of these potential source rocks at depth. We present four alternative burial history scenarios for a hypothetical well through the deepest portion of Yukon Flats basin. They differ from each other in the thicknesses of Upper Cretaceous and Cenozoic strata, the timing of initial basin subsidence, and the timing of inferred unconformities. The burial modeling results suggest a present-day depth to the oil window of approximately 6,000 feet.

  12. Long-term changes in microbial and biochemical parameters in the Central Indian Basin

    NASA Astrophysics Data System (ADS)

    Raghukumar, Chandralata; Nagender Nath, B.; Sharma, R.; Loka Bharathi, P. A.; Dalal, S. G.

    2006-10-01

    Natural kilometer-scale spatial variability and seasonal variability in deep-sea sediments at ˜5000 m depth was studied at two reference sites in the Central Indian Basin. Biochemical parameters such as the labile organic matter (LOM) (consisting of carbohydrates, protein and lipids) and total organic matter (TOM) and biological parameters such as total counts of bacteria and adenosine triphosphate (ATP) were estimated after an interval of 54 months. These were compared with nine locations (12-17 km away) where an artificial sediment disturbance was created by a hydraulic benthic disturber. Besides the above-mentioned parameters, extracellular enzymes, alkaline phosphatase, aminopeptidase and lipase were also monitored at these nine locations. Post-disturbance (PoD1) observations were carried out immediately after the benthic disturbance experiment and compared with the pre-disturbance (PreD) pattern. The restoration process in the test site was studied after a period of 44 months (PoD2). There was a drastic reduction in total counts of bacteria, ATP, carbohydrates and lipids accompanied by a two- to four-fold increase in protein content at the undisturbed reference sites after 54 months. A similar reduction in these parameters was observed in the PoD1 compared to the PreD stage at the test site. An initial increase in TOM content and in the activities of three extracellular enzymes in the PoD1 stage was followed by a reduction in TOM, ATP and organic P content and activities of the extracellular enzymes in the PoD2 phase (i.e. after 44 months). Reduction in ATP levels suggests a negative impact of resedimentation on living biomass in the sediments. Although LOM, protein concentrations and the protein/carbohydrate ratio increased in the PoD2 phase relative to the PoD1 phase, the bacterial numbers were below the concentrations in the PreD stage, indicating slow restoration of benthic conditions. Long-term analyses of the indicator parameters thus showed mixed

  13. Land-Cover Trends of the Central Basin and Range Ecoregion

    USGS Publications Warehouse

    Soulard, Christopher E.

    2006-01-01

    The U.S. Geological Survey (USGS) Land Cover Trends research project is focused on understanding the amounts, rates, trends, causes, and implications of contemporary land-use and land-cover (LU/LC) change in the United States. This project is supported by the USGS Geographic Analysis and Monitoring Program in collaboration with the U.S. Environmental Protection Agency (EPA) and the National Aeronautics and Space Administration (NASA). LU/LC change is a pervasive process that modifies landscape characteristics and affects a broad range of socioeconomic, biologic, and hydrologic systems. Understanding the impacts and feedbacks of LU/LC change on environmental systems requires an understanding of the rates, patterns, and driving forces of past, present, and future LU/LC change. The objectives of the Land Cover Trends project are to (1) determine and describe the amount, rates, and trends of contemporary LU/LC change by ecoregion for the period 1973-2000 for the conterminous United States, (2) document the causes, driving forces, and implications of change, and (3) synthesize individual ecoregion results into a national assessment of LU/LC change. The Land Cover Trends research team includes staff from the USGS National Center for Earth Resources Observation and Science (EROS), Rocky Mountain Geographic Science Center, Eastern Geographic Science Center, Mid-Continent Geographic Science Center, and the Western Geographic Science Center. Other partners include researchers at South Dakota State University, University of Southern Mississippi, and State University of New York College of Environmental Science and Forestry. This report presents an assessment of LU/LC change in the Central Basin and Range ecoregion for the period 1973-2000. The Central Basin and Range ecoregion is one of 84 Level-III ecoregions as defined by the Environmental Protection Agency. Ecoregions have served as a spatial framework for environmental resource management and to denote areas that contain

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

    USGS Publications Warehouse

    Duffy, Walter G.; Kahara, Sharon N.; Records, Rosemary M.

    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

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

    USGS Publications Warehouse

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

    1990-01-01

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

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

    USGS Publications Warehouse

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

    1990-01-01

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

  17. Mineralogy and Petrology of Basement Granites of the Cooper Basin, Central Australia

    NASA Astrophysics Data System (ADS)

    van Zyl, Jaco; Gasparon, Massimo; Uysal, Tonguc

    2010-05-01

    Mineralogy and Petrology of Basement Granites of the Cooper Basin, Central Australia Although the Australian continent is tectonically relatively stable in comparison with other continental settings, the radiogenic heat production within the Australian continental crust is significantly high. One region with particularly elevated heat production is the Cooper Basin. The Cooper basin is an intra-cratonic basin that contains Late Carboniferous to middle Triassic sedimentary rocks which is mainly comprised of non marine sediments. The Cooper Basin overlies granites which have intruded the Warburton Basin Sediments. The Cooper basin in turn is overlain by the Eromanga Basin. This paper focuses on four deep wells in which granites have been intersected. The aim of this study is to characterize the mineralogy and petrology of the granites to further the understanding of heat production. Ten petrographic thin-sections were made from the granites and sampled at different depths in the four geothermal wells. Eight (Big Lake-3507; McLeod-1-3745.2, 3745.9, 3748.3; Moomba-1 2847.75, 2848.7, 2851, 2847.4) of the ten samples exhibit minor to strong alteration, with the other two remaining samples (Jolokia-1 4905 and Moomba-1 2857.4) showing only slight alteration. The predominant mineral in the altered samples is quartz, and a highly birefringent clay mineral (illite from EPMA and XRD) with minor oxides (Goethite, Rutile) sulphides (Galena, Pyrite) and REE-rich silicates (Thorite, Zircon) and phosphates (Apatite, Monazite and Xenotime). The sections exhibiting minor alteration contain plagioclase and K-feldspar in varying stages of decomposition. These feldspars contain varying amounts of illite crystallites. The only altered mineral in the two slightly altered samples is biotite. In Jolokia 1- 4905 the biotite has been completely replaced by a Fe-bearing illite. In Moomba 1- 2857.4 the biotite is only in the early stages of alteration, with the alteration product being Fe

  18. 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).

  19. Oligocene to Pliocene palaeogeographic evolution of the Çankırı-Çorum Basin, central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Karadenizli, Levent

    2011-05-01

    The Çankırı-Çorum Basin is one of the largest basins of Central Anatolia to have developed Oligocene to Quaternary terrestrial environments. The basin contains significant raw materials for industry and energy, but the determination of their distribution patterns requires a good knowledge of the stratigraphic and spatial distribution of deposits. Besides, evolving tectonic regimes in the basin and the sedimentary sequences controlled by them can play key roles in revealing the regional paleogeography. On the basis of a new chronological framework provided by mammalian fossils and sedimentological data, ten sedimentary formations have been identified for the Oligocene-Pleistocene time interval. From the oldest to the youngest these are the İncik, Güvendik, Kızılırmak, Kılçak, Kumartaş, Hançili, Bayındır, Akkaşdağı, Bozkır and Değim formations. During Early Oligocene times, an alluvial fan and braided and meandering rivers deposits developed at the northern and eastern rims of the basin, whereas lacustrine products dominated by evaporitic deposits occurred in vast areas at the center. In Late Oligocene, the lake area contracted and dominant floodplains and braided rivers took place in the central area of the basin. During Early-Middle Miocene, large lacustrine areas dominated by organic/clastic deposits developed in the northern and middle parts of the basin; lake shore facies were formed in northern parts of the basin and on some paleohighs surrounding the lake. In the Orta and Şabanözü regions volcanic activity started during the Middle Miocene and lasted until the beginning of Late Miocene. During Late Miocene, there were different types of lacustrine environments in the northern and southern parts of the basin: a hypersaline lake characterized by evaporitic deposits in the north and carbonate-rich shallow lakes and swamps in the south. A younger evaporitic lake formed in Early Pliocene in the northern part of the basin and covered vast

  20. Part I: Neoacadian to Alleghanian foreland basin development and provenance in the central appalachian orogen, pine mountain thrust sheet Part II: Structural configuration of a modified Mesozoic to Cenozoic forearc basin system, south-central Alaska

    NASA Astrophysics Data System (ADS)

    Robertson, Peter Benjamin

    Foreland and forearc basins are large sediment repositories that form in response to tectonic loading and lithospheric flexure during orogenesis along convergent plate boundaries. In addition to their numerous valuable natural resources, these systems preserve important geologic information regarding the timing and intensity of deformation, uplift and erosion history, and subsidence history along collisional margins, and, in ancient systems, may provide more macroscopic information regarding climate, plate motion, and eustatic sea level fluctuations. This thesis presents two studies focused in the Paleozoic Appalachian foreland basin system along the eastern United States and in the Mesozoic to Cenozoic Matanuska forearc basin system in south-central Alaska. Strata of the Appalachian foreland basin system preserve the dynamic history of orogenesis and sediment dispersal along the east Laurentian margin, recording multiple episodes of deformation and basin development during Paleozoic time. A well-exposed, >600 m thick measured stratigraphic section of the Pine Mountain thrust sheet at Pound Gap, Kentucky affords one of the most complete exposures of Upper Devonian through Middle Pennsylvanian strata in the basin. These strata provide a window into which the foreland basin's development during two major collisional events known as the Acadian-Neoacadian and the Alleghanian orogenies can be observed. Lithofacies analysis of four major sedimentary successions observed in hanging wall strata record the upward transition from (1) a submarine deltaic fan complex developed on a distal to proximal prodelta in Late Devonian to Middle Mississippian time, to (2) a Middle to Late Mississippian carbonate bank system developed on a slowly subsiding, distal foreland ramp, which was drowned by (3) Late Mississippian renewed clastic influx to a tidally influenced, coastal deltaic complex to fluvial delta plain system unconformably overlain by (4) a fluvial braided river complex

  1. The early Mesozoic Birdsboro central Atlantic margin basin in the Mid-Atlantic region, eastern United States

    USGS Publications Warehouse

    Faill, R.T.

    2003-01-01

    The early Mesozoic Birdsboro basin (new name) was a single, elongate depositional trough in the present Mid-Atlantic area of the eastern United States, extending north-eastward from central Virginia across Maryland, Pennsylvania, and New Jersey into southern New York. What now remains after erosion comprises the Barboursville, Culpeper, Gettysburg, and Newark remnants. Some 7?? km of late Triassic and early Jurassic continental sediments of varying provenances entered and spread across in the Birdsboro basin in several depositional environments. The five resulting sedimentary lithosomes include feldspathic sandstone, quartzose sandstone, red silty mudstone, gray shale, and fanglomerate. The extensive interbedding, intertonguing, and lateral gradation among these lithosomes suggest that they were contemporary and closely interrelated. The feldspathic sandstone lithosome contains sediment with a southeastern provenance that accumulated in a bajada environment extending the length of the southeastern side of the basin. Sediment in the quartzose sandstone lithosome had a northwestern provenance-the coarse-grained fraction formed regional alluvial fans at the mouths of four major input centers. The finer-grained fraction was deposited in the distal reaches of these fans and in the playa environments in the interfan areas; this fraction formed the red silty mudstone lithosome. Gray/black shales and argillites of the gray shale lithosome accumulated in lacustrine environments in the interfan areas. The fanglomerate lithosome comprises numerous small, lobate deposits of poorly sorted sediment along both basin margins. The location and time of activity of the northwest input centers largely determined the distribution and areal extent of the various depositional environments and consequent lithosome along the length and across the width of the basin. The Birdsboro basin was deformed (tilted, faulted, and folded) sometime after the deposition of the youngest preserved rocks

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. The Loncopué Trough: A Cenozoic basin produced by extension in the southern Central Andes

    NASA Astrophysics Data System (ADS)

    Folguera, Andrés; Rojas Vera, Emilio; Bottesi, Germán; Zamora Valcarce, Gonzalo; Ramos, Victor A.

    2010-05-01

    The Loncopué Trough is located in the hinterland Andean zone between 36°30' and 39°S. It constitutes a topographic low bounded by normal faults and filled by lavas and sediments less than 5 Ma old. Reprocessed seismic lines show wedge-like depocenters up to 1700 m deep associated with high-angle faults, correlated with the 27-17 Ma Cura Mallín basin deposits, and buried beneath Pliocene to Quaternary successions and Late Miocene foreland sequences. The southern Central Andes seem to have been under extension in the hinterland zone some 27 Ma ago and again at approximately 5 Ma ago. This last extensional period could have been the product of slab steepening after a shallow subduction cycle in the area, although other alternatives are discussed. Orogenic wedge topography, altered by the first extensional stage in the area, was recovered through Late Miocene inversion, and was associated with foreland sequences. However, since the last extension (<5 Ma) the Andes have not recovered their characteristic contractional behavior that controlled past orogenic growth.

  7. 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

  8. Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy.

    PubMed

    Guzzetti; Cardinali; Reichenbach; Carrara

    2000-03-01

    / The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit.

  9. 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.

  10. 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.

  11. 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.

  12. Erosion surfaces and Neogene landscape evolution in the NE Duero Basin (north-central Spain)

    NASA Astrophysics Data System (ADS)

    Benito-Calvo, Alfonso; Pérez-González, Alfredo

    2007-08-01

    We present a chronological model of erosion surface development in the Iberian and Cantabrian Ranges of north-central Spain. We map four erosion surfaces and interpret these to be related to Duero basin continental sediments and tectonic activity from Upper Oligocene to Plio-Pleistocene. The oldest erosion surface, SE1, formed across Upper Oligocene-Lower Miocene synorogenic deposits; while surface SE2 was contemporaneous with the Middle Miocene alluvial systems, ending with an uplift stage in the Astaracian. The two most recent erosion surfaces, SE3 and SE4, developed during extensional tectonic episodes and are associated with the deposition of Upper Páramo sedimentary units at the end of the Miocene (Upper Turolian) and alluvial fan deposits, known as rañas (Plio-Pleistocene). With the exception of SE1, which seems to be associated with a relatively wet climate, the surfaces formed during periods of marked aridity and generally warm temperatures. Through geostatistical reconstruction of the best preserved surface (SE2), applying ordinary kriging method to the topography (DEM) of the erosion surface and its correlating sedimentary plains, we identify the deformation processes which occurred on this surface after its formation.

  13. 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.

  14. 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

  15. 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.

  16. 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

  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. Mesozoic and Cenozoic tectonics of the eastern and central Alaska Range: Progressive basin development and deformation in a suture zone

    USGS Publications Warehouse

    Ridgway, K.D.; Trop, J.M.; Nokleberg, W.J.; Davidson, C.M.; Eastham, K.R.

    2002-01-01

    Analysis of late Mesozoic and Cenozoic sedimentary basins, metamorphic rocks, and major faults in the eastern and central Alaska Range documents the progressive development of a suture zone that formed as a result of collision of an island-arc assemblage (the Wrangellia composite terrane) with the former North American continental margin. New basin-analysis, structural, and geochronologic data indicate the following stages in the development of the suture zone: (1) Deposition of 3-5 km of Upper Jurassic-Upper Cretaceous marine strata (the Kahiltna assemblage) recorded the initial collision of the island-arc assemblage with the continental margin. The Kahiltna assemblage exposed in the northern Talkeetna Mountains represents a Kimmeridgian-Valanginian backarc basin that was filled by northwestward-flowing submarine-fan systems that were transporting sediment derived from Mesozoic strata of the island-arc assemblage. The Kahiltna assemblage exposed in the southern Alaska Range represents a Valanginian-Cenomanian remnant ocean basin filled by west-southwestward-flowing submarine-fan systems that were transporting sediment derived from Paleozoic continental-margin strata uplifted in the along-strike suture zone. A belt of retrograde metamorphism and a regional anticlinorium developed along the continental margin from 115 to 106 Ma, roughly coeval with the end of widespread deposition in the Kahiltna sedimentary basins. (2) Metamorphism of submarine-fan deposits of the Kahiltna basin, located near the leading edge of the island-arc assemblage, occurred at ca. 74 Ma, as determined from a new U-Pb zircon age for a synkinematic sill. Coeval with metamorphism of deposits of the Kahiltna basin in the southern part of the suture zone was development of a thrust-top basin, the Cantwell basin, in the northern part of the suture zone. Geologic mapping and compositional data suggest that the 4 km of Upper Cretaceous nonmarine and marginal marine sedimentary strata in this basin

  19. 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.

  20. 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

  1. Predicting wood pellet stove ownership and acquisition in Albuquerque, NM

    SciTech Connect

    Lansford, R.; Skaggs, R.; Owensby, F.

    1994-12-31

    Wood pellet stove (WPS) ownership and acquisition in Albuquerque, New Mexico was predicted using a model of qualitative choice. Using data obtained from a telephone survey, households were divided into four groups: current WPS owners, non-owners considering ownership, non-owners not considering ownership, and those who had not heard of WPS technology. Variables used to predict what category a household will be in include homeowners` socioeconomic and home-heating characteristics. Results indicate few WPS stoves are currently in use in Albuquerque. However, current WPS owners and those considering WPS acquisition tend to have higher incomes, more years of education, larger homes, and use their fireplaces more frequently than average. Clean air regulations in Albuquerque will require changes in home woodburning. The WPS is an efficient and clean device; however, lack of knowledge of WPS technology, satisfaction with current heating systems, and limited awareness of the potential impact of clean air regulations indicate WPS usage in Albuquerque will remain limited.

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Volcanic facies, structure, and geochemistry of the marginal basin rocks of central Peru

    NASA Astrophysics Data System (ADS)

    Atherton, M. P.; Webb, S.

    The western part of the Mesozoic Peruvian Trough, the Huarmey Basin, has a fill of pillow lavas, sheet lavas, hyaloclastites, tuffs and minor cherts, siliceous and calcareous oozes. Maximum subsidence occurred in the Albian when 9000 meters of basin fill accumulated. This was later intruded by gabbros and dikes and then the Coastal Batholith. The basin is an extensional marginal basin continuous with other basins of similar age to the south. Facies analyses indicate that the basin was relatively deep, with no continental influx, and not dissimilar to spreading and off-axis systems on the ocean floor. Structures at the surface and at depth indicate the crust has split and the basin was floored by mantle material. The basin shows a marked polarity, with tholeiitic basaltic rocks at the center and high-K acid rocks at the eastern margin, with intermediate types between. These changes in petrology and chemistry relate to lateral changes in source composition. Secular variations are also present and indicate a calcalkali source giving way to a more MORB-like source with a variable continental component. The basin is part of the major rifting event in the Cretaceous which affected the whole western margin of South America and was an important and necessary precursor to major batholith intrusion.

  8. 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

  9. 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.

  10. 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.

  11. Implications for Fault and Basin Geometry in the Central California Coast Ranges from Preliminary Gravity and Magnetic Data

    NASA Astrophysics Data System (ADS)

    Langenheim, V. E.; Jachens, R. C.; Graymer, R. W.; Wentworth, C. M.

    2008-12-01

    Preliminary aeromagnetic and newly processed gravity data help define block-bounding faults and deep sedimentary basins in the central California Coast Ranges, ranging from the Hosgri fault east to the San Andreas fault and from Monterey Bay south to Pt. Conception. Interpretation of these data results in an improved framework for seismic hazard and groundwater studies. Aeromagnetic data include a new survey with a flight-line spacing of 800 m at a nominal 300 m above ground and covering 15,000 km2. More than 11,500 gravity measurements, reprocessed with terrain corrections calculated from 30-m DEMs, form a roughly 2-km grid over most of the study area. Combined potential-field data and existing geologic mapping, delineate major fault-bounded blocks in the central California Coast Ranges. Main block-bounding faults from west to east include the San Gregorio- Hosgri, San Luis-Willmar-Santa Maria River-Little Pine, Oceanic-West Huasna, Nacimiento, Rinconada-South Cuyama, San Juan-Chimineas-Morales, and San Andreas faults. Most of these faults have evidence of Quaternary activity. Gravity gradients indicate that the reach of the San Andreas fault bounding the Gabilan Range and the northern extension of the Rinconada fault bounding the Santa Lucia Range dip steeply southwestward and have a reverse component of slip. Magnetic and microseismicity data suggest that the northern reach of the Hosgri fault dips eastward. The potential-field data also delineate several deep sedimentary basins, such as the 3-4 km deep Cuyama basin, the Santa Maria basin, and several basins along and possibly offset by the Rinconada fault. Gravity data show that the main west-northwest-striking faults bounding the Cuyama basin dip away from the basin, indicating compression adjacent to the big bend in the San Andreas fault. Prominent gravity and magnetic highs northeast of the San Andreas fault immediately east of Cuyama Valley suggest that there the San Andreas fault dips southwest. Such dip

  12. 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

  13. 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

  14. 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

  15. Uranium-bearing coal in the central part of the Great Divide basin, Sweetwater County, Wyoming

    USGS Publications Warehouse

    Pipiringos, George Nicholas

    1956-01-01

    Field work leading to this report was done by the U.S. Geological Survey for the Division of Raw Materials of the U.S. Atomic Energy Commission. Nearly 24 townships were mapped in the central part of the Great Divide Basin, Sweetwater County, Wyoming. Fourteen of these townships contain outcrops of uranium-bearing coal. Thirty coal beds were mapped, but only seven of them have uranium-bearing coal reserves as defined in this report. Coal beds 2.5 or more feet thick are considered in calculating coal reserves, and of these, only beds containing 0.003 or more percent uranium are considered in calculating reserves of uranium in coal. Reserves of uranium in coal ash include those beds 2.5 or more feet thick that contain 0.015 or more percent uranium in coal ash. Measured and indicated coal reserves total about 700,000,000 short tons which contain about 2,600 short tons of uranium in the coal, or about 2,400 short tons of uranium in the coal ash. Strippable reserves, defined as reserves in beds beneath 60 or less feet of overburden, are about 250,000,000 short tons of coal containing about 1,100 short tons of uranium in coal, or about 600 tons of uranium in coal ash. The thickest coal beds underlie a relatively narrow belt that trends northwest and coincides approximately with the axis of the Red Desert syncline. The coal beds contain the most uranium on the east flank of the syncline near the southwesternmost edge of the Battle Spring formation (new). This formation is of early and middle Eocene age and consists predominantly of very coarse-grained arkosic sandstone which is highly permeable. It intertongues southwestward with the Tess permeable Green River and Wasatch formations. The Green River formation consists from youngest to oldest of the Morrow Creek and Laney shale members and the Tipton and Luman (new) tongues. The Wasatch formation interfingers with the Green River formation and consists from youngest to oldest of the Cathedral Bluffs, Niland, and Red Desert

  16. Drought assessment in the Duero basin (Central Spain) by means of multivariate extreme value statistics

    NASA Astrophysics Data System (ADS)

    Kallache, M.

    2012-04-01

    Droughts cause important losses. On the Iberian Peninsula, for example, non-irrigated agriculture and the tourism sector are affected in regular intervals. The goal of this study is the description of droughts and their dependence in the Duero basin in Central Spain. To do so, daily or monthly precipitation data is used. Here cumulative precipitation deficits below a threshold define meteorological droughts. This drought indicator is similar to the commonly used standard precipitation index. However, here the focus lies on the modeling of severe droughts, which is done by applying multivariate extreme value theory (MEVT) to model extreme drought events. Data from several stations are assessed jointly, thus the uncertainty of the results is reduced. Droughts are a complex phenomenon, their severity, spatial extension and duration has to be taken into account. Our approach captures severity and spatial extension. In general we find a high correlation between deficit volumes and drought duration, thus the duration is not explicitely modeled. We apply a MEVT model with asymmetric logistic dependence function, which is capable to model asymptotic dependence and independence (cf. Ramos and Ledford, 2009). To summarize the information on the dependence in the joint tail of the extreme drought events, we utilise the fragility index (Geluk et al., 2007). Results show that droughts also occur frequently in winter. Moreover, it is very common for one site to suffer dry conditions, whilst neighboring areas experience normal or even humid conditions. Interpolation is thus difficult. Bivariate extremal dependence is present in the data. However, most stations are at least asymptotically independent. The according fragility indices are important information for risk calculations. The emerging spatial patterns for bivariate dependence are mostly influenced by topography. When looking at the dependence between more than two stations, it shows that joint extremes can occur more

  17. 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.

  18. Resistivity structures across the Humboldt River basin, north-central Nevada

    USGS Publications Warehouse

    Rodriguez, Brian D.; Williams, Jackie M.

    2002-01-01

    Magnetotelluric data collected along five profiles show deep resistivity structures beneath the Battle Mountain-Eureka and Carlin gold trends in north-central Nevada, which appear consistent with tectonic breaks in the crust that possibly served as channels for hydrothermal fluids. It seems likely that gold deposits along these linear trends were, therefore, controlled by deep regional crustal fault systems. Two-dimensional resistivity modeling of the magnetotelluric data generally show resistive (30 to 1,000 ohm-m) crustal blocks broken by sub-vertical, two-dimensional, conductive (1 to 10 ohmm) zones that are indicative of large-scale crustal fault zones. These inferred fault zones are regional in scale, trend northeast-southwest, north-south, and northwest-southeast, and extend to mid-crustal (20 km) depths. The conductors are about 2- to 15-km wide, extend from about 1 to 4 km below the surface to about 20 km depth, and show two-dimensional electrical structure. By connecting the locations of similar trending conductors together, individual regional crustal fault zones within the upper crust can be inferred that range from about 4- to 10-km wide and about 30- to 150-km long. One of these crustal fault zones coincides with the Battle Mountain-Eureka mineral trend. The interpreted electrical property sections also show regional changes in the resistive crust from south to north. Most of the subsurface in the upper 20 km beneath Reese River Valley and southern Boulder Valley are underlain by rock that is generally more conductive than the subsurface beneath Kelly Creek Basin and northern Boulder Valley. This suggests that either elevated-temperature or high-salinity fluids, alteration, or carbonaceous rocks are more pervasive in the more conductive area (Battle Mountain Heat-Flow High), which implies that the crust beneath these valleys is either more fractured or has more carbonaceous rocks than in the area surveyed along the 41st parallel.

  19. Herpetofauna of the cedar glades and associated habitats of the Inner Central Basin of middle Tennessee

    USGS Publications Warehouse

    Niemiller, M.L.; Graham, Reynolds R.; Glorioso, B.M.; Spiess, J.; Miller, B.T.

    2011-01-01

    The cedar glades and barrens of the Inner Central Basin (ICB) of middle Tennessee support a unique and diverse flora and fauna and represent some of the state's most valued natural areas. We conducted herpetofaunal inventories of the cedar glades, associated barrens, cedar-hardwood forest, and adjacent aquatic habitats of the Stones River drainage of Middle Tennessee, focusing our sampling effort primarily at seven state- or federally owned properties in Rutherford and Wilson counties. These properties included Stones River National Battlefield (SRNB), Flat Rock State Natural Area (FRSNA), Vesta Cedar Glade State Natural Area (VSNA), Fall Creek Recreation Area (FCRA) on J. Percy Priest Wildlife Management Area, Cedars of Lebanon State Forest (CLSF), Cedars of Lebanon State Forest Natural Area (CLSNA), and Cedars of Lebanon State Park (CLSP). We used a variety of inventory techniques in terrestrial, aquatic, and subterranean habitats to survey these properties periodically from 1989 to 2010. We documented 49 species (22 amphibian and 27 reptile) accounting for 75.4% of the 65 herpetofaunal species thought to occur in the ICB, including records for Cemophora coccinea, Aneides aeneus, Gyrinophilus palleucus, Ambystoma barbouri, and Pseudotriton montanus. We found differences in alpha and beta diversity between sites, with the CLSF complex containing a high of 41 herpetofaunal species and FRSNA containing a low of 23 species. Beta diversity comparisons indicated similarity in amphibian species composition between FRSNA and CLSF and between SRNB and CLSF (9 shared species), and in reptile species composition between VSNA and the CLSF complex (16 shared species). We compare the results of our inventory with two previous studies conducted in the area and discuss the relative abundance, conservation, and threats to the herpetofaunal community of these habitats.

  20. Volcanology of the Aries micaceous kimberlite, central Kimberley Basin, Western Australia

    NASA Astrophysics Data System (ADS)

    Downes, Peter J.; Ferguson, Dale; Griffin, Brendan J.

    2007-01-01

    The Neoproterozoic (815.4 ± 4.3 Ma) Aries kimberlite intrudes the King Leopold Sandstone and the Carson Volcanics in the central Kimberley Basin, northern Western Australia. Aries is comprised of a N-NNE-trending series of three diatremes and associated hypabyssal kimberlite dykes and plugs. The diatremes are volumetrically dominated by massive, clast-supported, accidental lithic-rich kimberlite breccias that were intruded by hypabyssal macrocrystic phlogopite kimberlite dykes and plugs with variably uniform- to globular segregationary-textured groundmasses. Lower-diatreme facies, accidental lithic-rich breccias probably formed through fall-back of debris into the vent with a major contribution from the collapse of the vent walls. These massive breccias are overlain by a sequence of bedded volcaniclastic breccias in the upper part of the north lobe diatreme. Abundant, poorly vesicular to nonvesicular, juvenile kimberlite ash and lapilli, with morphologies that are indicative of phreatomagmatic fragmentation processes, occur in a reversely graded volcaniclastic kimberlite breccia unit at the base of this sequence. This unit and overlying bedded accidental lithic-rich breccias are interpreted to be sediment gravity-flow deposits (including possible debris flows) derived from the collapse of the crater walls and/or tephra ring deposits that surrounded the crater. Diatreme-forming eruptions may have been initiated by magma-water interactions along fracture and joint-controlled aquifers within the King Leopold Sandstone. The current level of exposure of the diatremes probably extends from the lower-diatreme facies up into the base of a bedded upper-diatreme sequence.

  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. 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

  3. Chronology of late Quaternary glaciation in the Pindar valley, Alaknanda basin, Central Himalaya (India)

    NASA Astrophysics Data System (ADS)

    Bali, Rameshwar; Nawaz Ali, S.; Agarwal, K. K.; Rastogi, Saurabh Kumar; Krishna, Kalyan; Srivastava, Pradeep

    2013-04-01

    Palaeoglacial reconstruction based on geomorphological mapping in the Pindari glacier valley, Alaknanda basin (Central Himalaya), has revealed five glacial stages with decreasing magnitude. The oldest and most extensive stage-I glaciation deposited sediments at ˜2200 masl (Khati village). The stage-II glaciation was around 7 km long and luminescence dated to 25 ± 2 ka, and has deposits at 3200 masl (Phurkia village). Stage-III glaciation is represented by degraded linear moraine ridges and is dated to 6 ± 1 ka and its remnants can be found around 3850 masl. A sharp crested crescentic moraine extending from around 3650 masl to 3900 masl is attributed to stage-IV glaciation and is dated to 3 ± 1 ka. Following this, there appears to have been a gradual recession in Pindari glacier as indicated by four sharp crested unconsolidated moraines (stage-V) on the valley floor which abuts the stage-IV moraine. We suggest that the stage-I glaciation occurred during the cool and wet Marine Isotopic Stage 3/4 (MIS-3/4), stage-II glaciations began with the onset of MIS-2, whereas the stage-III and IV glaciations occurred during the mid-to late Holocene (MIS-1). We speculate that the first sharp crested unconsolidated moraines around 3600 masl correspond to the later phase of the Little Ice Age (LIA). Historical data suggests that the remaining three ridges represent Pindari glacier snout positions at 1906, 1958 and 1965. We argue that the late Quaternary glaciations in the Pindar valley were modulated by changing insolation and summer monsoon intensity including the LIA, whereas the 20th century recessional trends can be attributed to post-LIA warming.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. 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...

  10. 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...

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

    NASA Astrophysics Data System (ADS)

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

    1999-01-01

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

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

    USGS Publications Warehouse

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

    1999-01-01

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

  13. 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.

  14. The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

    NASA Astrophysics Data System (ADS)

    Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

    1995-04-01

    The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

  15. 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.

  16. 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

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

    USGS Publications Warehouse

    Anderson, T.W.

    1980-01-01

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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Aerosol emissions from forest and grassland burnings in the southern amazon basin and central Brazil

    NASA Astrophysics Data System (ADS)

    Leslie, Alistair C. D.

    1981-03-01

    using the "HEXB" program. One of the prominent features found was the large flux of small particles (<2.0 μm) from both fire types. P, S and Cl were mostly small particle, Mg, Al, Si and K showed a bimodal distribution biased towards the small particle range, while Ca, Ti and Fe (crustal elements) predominated in the large particle mode. As Cl was found to be exclusively small particle, a formation mechanism in which HCl gas neutralizes small organic particles containing P and S may be hypothesized. A much more extensive field program for the summer of 1980 is planned to take place in the central Amazon basin using ground and airborne aerosol samplers, to capitalize on the work pioneered in this study.

  4. Updating landslide inventory maps using Persistent Scatterers Interferometry (PSI) in the Biferno River Basin (Central Italy)

    NASA Astrophysics Data System (ADS)

    Righini, Gaia; Pancioli, Valeria; Casagli, Nicola

    2010-05-01

    This work illustrates the contribution of Persistent Scatterers Interferometry (PSI) from radar satellites ERS and ENVISAT for the updating of a pre-existing landslide inventory map: the main purpose is to change or confirm the landslide state of activity and geometry and to identify new landslides. PSI results are integrated with optical images and ancillary data in a 1320 km2 wide river basin (Biferno Basin) located in the central-eastern part of Italy: in particular a new contribution to the interpretation of persistent scatterers information is presented. The geological setting of the area, characterised by clay and alternated clayey, silty and sandy formation, that are affected by slow landslides, fits very well with the use of radar data. The analysis is performed on results from the PSInSAR(™) (Permanent Scatterers SAR Interferometry) technique provided by TeleRilevamento Europa. The updating is obtained through the integration of conventional photo-interpretation and the radar-interpretation chain; the information coming from radar-interpretation is the basis of the proposed method to evaluate the state of activity and the intensity of slow landslides. The interferometric data provide estimates of the mean yearly velocity referred to two distinct time intervals: historic ERS (1992-2001) and recent ENVISAT (2002-2007). The integration of the photo-interpretation gives a fundamental contribution to landslide mapping in particular in hilly and mountainous environments where there is a low density of radar benchmarks. In field validation confirmed the results and the capabilities of multi-interferometric InSAR data, integrated and coupled with conventional techniques, to support landslides investigation at regional scale thanks to the available archive of repeated satellite data which provide measurements of ground displacements with a millimeter scale accuracy. In the study area about 9% of the pre-existing landslide inventory has been modified by means of

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Hydrologic classification and estimation of basin and hydrologic characteristics of subbasins in central Idaho

    USGS Publications Warehouse

    Lipscomb, Stephen W.

    1998-01-01

    Hydrologic data for streams and associated subbasins within the Salmon and Clearwater river basins were analyzed to support instream flow claims by the Bureau of Indian Affairs on behalf of the Nez Perce Indian Tribe. A geographic information system was used to construct a data base of basin characteristics for 1,050 subbasins. Descriptive variables were used to classify these subbasins and compute estimates of flow characteristics.

  10. Paleoceanography of the Eocene Central Arctic Basin Based on Geochemical Measurements of Biogenic Matter

    NASA Astrophysics Data System (ADS)

    Takahashi, K.-; Ogawa, Y.-; Onodera, J.-

    2006-12-01

    The IODP Leg 302 Arctic Coring Expedition retrieved approximately 120 m long continuous Eocene section from the Lomonosov Ridge in the central Arctic for the first time. The Eocene section is lithologically classified into Unit 2 with the assigned age of ~49-44Ma below and Unit 1/6 with 44Ma above the unit boundary. Unit 2 consists of very dark gray mud bearing siliceous ooze and Unit 1/6 consists of very dark gray silty clay to clayey silt. Biogenic opal (293 samples), organic carbon, nitrogen, and sulfur (150 samples) were measured. The sample resolutions are approximately 16 kyrs for Unit 2 and 8 kyrs interval for Unit 1/6, respectively. In Unit 2 biogenic opal ranged from 40 to 70% whereas in Unit 1/6, it decreased down to 10-20%, except for a peak of 37% at approximately 203 mbsf. Organic carbon consistently showed high values such as 1.4-5.7% both in Units 2 and 1/6. C/N ratios ranged from 15 to 20. Sulfur values ranged 2.6-7.7% in Unit 2 and it significantly increased to 4.0-19.4% in Unit 1/6. Based on the presence of abundant framboidal pyrites and the observed extremely low C/S ratios of <1.2 clearly indicate that the basin was under euxinic marine condition with sluggish bottom water circulation. Siliceous plankton mainly contributed to the biological productivity from 250 to 220 mbsf in Unit 2 and from 216 to 207 mbsf in Unit 1/6, judging from positive correlations of %biogenic opal vs %organic carbon. In other parts of the section such a positive correlation was not seen, implying something else other than siliceous plankton mainly contributed the total productivity. From Unit 2 to Unit 1/6, three rather drastic environmental changes are suggested: decrease of siliceous plankton productivity, increase of sulfate availability, and intensification of the euxinic conditions. In Unit 1/6 where sulfur values significantly increased, an increase of marine water inflow from the North Atlantic suggested by a study on silicofragellates assemblages. The marine

  11. Nutrient Loads and Ground-Water Residence Times in an Agricultural Basin in North-Central Connecticut

    USGS Publications Warehouse

    Mullaney, John R.

    2007-01-01

    Nutrient loads from ground-water discharge were studied in Broad Brook Basin, a 15.8-square mile basin in north-central Connecticut, dominated by agricultural activity. Loads were calculated, along with the travel times of ground water from recharge to discharge areas, to estimate the time required for the effects of Best Management Practices (BMPs) to be observed. Most concentrations of nitrogen and phosphorus in Broad Brook exceeded U.S. Environmental Protection Agency Ecoregion XIV nutrient criteria for streams. During the study period (1993-2004), annual loads of nitrogen from Broad Brook Basin ranged from 117,000 to 270,000 pounds (lb), and yields were about 10 times larger than those from forested basins in Connecticut. Ground-water discharge from the aquifer to the streams (base flow) during the study period was estimated with hydrograph separation and accounted for 82 percent of the total runoff from the basin. Nitrate nitrogen in base flow averaged 71 percent of the annual load of total nitrogen discharged from the basin, indicating that the largest source of nitrogen was likely from ground-water discharge. Annual loads of total phosphorus from the basin ranged from 2,330 to 14,400 lb, and yields were about five times higher than those from forested basins in Connecticut. Dissolved phosphorus averaged about 71 percent of the total phosphorus load, and ground-water discharge accounted for only as much as 40 percent of the annual load of dissolved phosphorus; therefore, phosphorus loads are dominated by stormwater-runoff events. Ground-water samples collected from 11 wells in the basin contained elevated concentrations of nitrite plus nitrate nitrogen. Dissolved gas analyses indicated that little denitrification was occurring in the aquifer. Apparent ages of the ground-water samples ranged from greater than 2 to more than 50 years based on sulfur hexafluoride, tritium, and tritium/helium-3 analyses. A three-dimensional ground-water-flow model was used in

  12. 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.

  13. 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.

  14. 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.

  15. Geomorphic Constraints on Patterns of Shortening and Erosion in the Puli Basin: Hinterland of the Central Taiwan Thrust Belt

    NASA Astrophysics Data System (ADS)

    Powell, L.; Mueller, K.; Chen, Y.

    2002-12-01

    Field mapping and structural restorations of deformed late Quaternary strata deposited in the Puli Basin reveal a strong correlation between erosion and recent activation and growth of compressional structures in the hinterland of the central Taiwan thrust belt. Sediments in the Puli Basin are deposited between topographic highs above the Shuangtung and Shuichanglin thrusts to the west and a higher mountain front bounded by the Tili and Meiyuan thrusts to the east. Outcrops of the Eocene Paileng Formation and Oligocene Shuichangliu Formation surrounding the basin suggest that a series of west-verging fault propagation folds accommodated shortening within the hanging wall of the Shuichanglin thrust prior to their being eroded. Late Quaternary strata of the Puli Basin were deposited above the older partially eroded fault-propagation folds and comprise an asymmetric, coarsening-upward sequence of clay, silt, coal, and cobbly alluvium that thickens to over 150 meters towards the west. The alluvium forms smooth terrace surfaces that lie up to 500 meters above present river channels and are characterized by numerous lateritic soil horizons, including the present lateritic surface soil profile that averages 1 meter in thickness. Although we are currently working to define the syntectonic growth architecture of sediments in the Puli Basin, initial mapping suggests growth across individual folds climbs upsection from west to east, recording an eastward progression of the locus of shortening beneath the Late Quaternary deposits. Folding of very young terraces without lateritic soil profiles within the Puli Basin and along the Peikang River north of the basin suggests that faults continue to be active beneath the central and eastern parts of the basin, possibly along a blind fault segment of the Meiyuan thrust. Cobbles within lateritic alluvial deposits in the Puli Basin consist of sandstone and argillite derived primarily from the local Paileng Formation exposed in fold

  16. Major variation of paleo-maximum temperature and consolidation state within post Miocene forearc basin, central Japan

    NASA Astrophysics Data System (ADS)

    Kamiya, N.; Yamamoto, Y.; Takemura, T.

    2015-12-01

    Since forearc-basin evolve associated with development of the accretionary prisms, their geologic structures have clues to understanding the tectonic processes associated with plate subduction. We found a major difference in paleo-geothermal structure and consolidation states between the unconformity in the forearc basin in the Boso Peninsula, central Japan. The geology of the Boso Peninsula, central Japan is divided into three parts; Early Miocene and Late Miocene accretionary prisms in the southern part, the Hayama-Mineoka tectonic belt mainly composed of ophiolite in the middle part, and post-Middle Miocene forearc basin in the northern part. Sediments in the forearc basin are composed of 15-3Ma Miura Group and 3-0.6Ma Kazusa Group. Boundary of the two groups is the Kurotaki Unconformity formed about 3Ma, when convergent direction of the Philippine Sea Plate has been changed (Takahashi, 2006). Vitrinite reflectance (Ro) analyses were conducted and revealed that major variation of paleo-maximum temperature between the Miura and Kazusa groups. The maximum paleo-temperature in the Miura Group is estimated as 70-95˚C, whereas in the lower part of the Kazusa Group is less than 10-35˚C. Given 20˚C/km (Sakai et al, 2011) paleo-geothermal gradient, approximately 2000 m uplifting/erosion of the Miura Group is expected when the unconformity formed. To verify the amount of this uplifting/erosion, we are performing consolidation test of mudstone. [Reference] Takahashi, M., 2006, Tectonic Development of the Japanese Islands Controlled by Philippine Sea Plate Motion, Journal of Geography, 115, 116-123. Sakai R., Munakata M., Kimura H., Ichikawa Y., and Nakamura M., 2011, Study on Validation Method of Regional Groundwater Flow Model : Case Study for Boso Peninsula, JAEA-research 2010(66), 1-20, 1-2.

  17. 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

  18. Surface waters of Cottonwood Creek in the Cimarron River basin in central Oklahoma

    USGS Publications Warehouse

    Laine, L.L.

    1962-01-01

    Annual discharge from Cottonwood Creek basin is estimated to have averaged 73,000 acre-ft during a 19-year base period, water years 1938-56, equivalent to an average annual runoff depth of 3.6 inches over the 380 square-mile drainage area. About 30,000 acre-ft per year comes from Deer Creek basin, a tributary drainage of 155 square miles. Yearly streamflow is highly variable. The discharge of Bluff Creek above Lake Hefner, near Oklahoma City, a small sub-basin of 1.62 square miles in Deer Creek basin, has varied from 484 acre-ft in 1951 to 55 acre-ft in 1956, a ratio of 9 to 1 during the period of record 1950-58. Highest runoff within a year tends to occur in the spring months of April through June, a 3-month period that, on the average, accounts for about 60 percent of the annual discharge of Cottonwood Creek. Lowest streamflow usually occurs in August and September. Occurrence of no flow in some years has been observed in the lower part of the basin and in the upper parts of Bluff Creek and Chisholm Creek basins. Variation in daily streamflow is such that the estimated average discharge of 97 cfs (cubic feet per second) for Cottonwood Creek just upstream from Guthrie is exceeded only 12 percent of the time and the daily discharge is more than 16 cfs only half of the time. There is no flow at the site about 7 percent of the time, assuming conditions of basin development prevailing in the last decade. Base flow in parts of the basin is augmented to some extent by seepage from reservoirs. In Bluff Creek basin, the seepage from Lake Hefner toward Spring Creek is 0.2 to 0.3 acre-ft per day; that toward Bluff Creek ranges from 1.7 to 3 acre-ft per day, depending on variation of reservoir level in the top 6 feet of capacity; and that toward Dry Creek is 0.3 to 0.4 acre-ft per day. Low flow in Chisholm Creek is sustained by sewage effluent from The Village, averaging 3 acre-ft per day. The surface waters of Cottonwood Creek basin are hard but in general are usable for

  19. Fish communities of the Sacramento River Basin: Implications for conservation of native fishes in the Central Valley, California

    USGS Publications Warehouse

    May, J.T.; Brown, L.R.

    2002-01-01

    The associations of resident fish communities with environmental variables and stream condition were evaluated at representative sites within the Sacramento River Basin, California between 1996 and 1998 using multivariate ordination techniques and by calculating six fish community metrics. In addition, the results of the current study were compared with recent studies in the San Joaquin River drainage to provide a wider perspective of the condition of resident fish communities in the Central Valley of California as a whole. Within the Sacramento drainage, species distributions were correlated with elevational and substrate size gradients; however, the elevation of a sampling site was correlated with a suite of water-quality and habitat variables that are indicative of land use effects on physiochemical stream parameters. Four fish community metrics - percentage of native fish, percentage of intolerant fish, number of tolerant species, and percentage of fish with external anomalies - were responsive to environmental quality. Comparisons between the current study and recent studies in the San Joaquin River drainage suggested that differences in water-management practices may have significant effects on native species fish community structure. Additionally, the results of the current study suggest that index of biotic integrity-type indices can be developed for the Sacramento River Basin and possibly the entire Central Valley, California. The protection of native fish communities in the Central Valley and other arid environments continues to be a conflict between human needs for water resources and the requirements of aquatic ecosystems; preservation of these ecosystems will require innovative management strategies.

  20. 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.

  1. 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.

  2. Basin evolution during change from convergent to transform continental margin in Central California

    SciTech Connect

    Graham, S.A.; Hitzman, M.; McCloy, C.; Turner, R.; Ward, R.

    1984-03-01

    Miocene nonmarine and shallow marine strata exposed east of San Francisco Bay record a change from convergent-margin tectonics to transform margin tectonics. During the middle Miocene, the East Bay area occupied the oceanward side of a shelved forearc basin that was progressively incorporated in the evolving San Andreas strike-slip orogene. Patterns of deposition in the broad forearc basin were relatively simple: andesitic arc-derived detritus was transported the full width of the forearc basin from the Sierras to the East Bay area. In contrast, the wrench-tectonic regime produced complex patterns of sedimentation displaying greater local variability. On the basis of stratigraphic data, we infer that the west-facing slope of the forearc basin in the East Bay area was reversed about 13 Ma with uplift of the area between the eventual traces of the San Andreas and Hayward faults on the site of the present bay. A fluvial clastic wedge was shed eastward into the East Bay area from this uplifted terrane of Mesozoic subduction complex and forearc basin rocks. Initial rupturing along the Hayward fault trend followed the uplift at about 10 Ma. Loci of basaltic volcanism (10-7 Ma) along these fractures interfinger with the clastic wedge. A similar pattern of uplift and drainage reversal apparently presaged the onset of wrenching along the nearby Calaveras trend from 8-6 Ma. Expansion of the strike-slip orogene segmented the outer forearc basin into local basins, some characterized by episodic lacustrine deposition and probable internal drainage. By the end of the Miocene, Sierran arc volcanism waned at the latitude of San Francisco Bay, and arc-derived volcaniclastics were fully supplanted by recycled Coast Range-derived detritus in the East Bay area. Certain of these Coast Range sediment sources, particularly blueschist-bearing Franciscan terranes, permit an estimate of 7-27 km (4-17 mi) of total right slip on the Hayward fault.

  3. Geochronology and geochemistry of deep-drill-core samples from the basement of the central Tarim basin

    NASA Astrophysics Data System (ADS)

    Guo, Zhao-Jie; Yin, An; Robinson, Alexander; Jia, Cheng-Zao

    2005-04-01

    The Tarim basin between the Tibetan plateau to the south and Tian Shan to the north in the Indo-Asian collision zone is little deformed as indicated by flat-lying Cenozoic strata across much of the basin. Due to the lack of direct observations from its crystalline basement, the geologic setting for the existence of such a rigid Cenozoic block remains elusive. Hypotheses for the nature of the Tarim basement include (1) Precambrian basement, (2) late Paleozoic trapped oceanic basin, (3) a late Precambrian failed rift, and (4) a Precambrian oceanic plateau. These models make specific predictions about the age and composition of the Tarim basement. To test these hypotheses, we conduct geochemical and geochronologic analyses of samples recovered from a deep well that reached a depth of >7000 m and drilled into the crystalline basement for ˜35 m beneath the central Tarim basin. Mineralogical composition and major element analysis suggest that the crystalline from the drill core is a diorite. Under think sections the rocks samples consist of fine-grained (0.1-0.4 mm in the longest dimension) and medium-grain domains (2-3 mm in the longest dimension). The contact between the two domains is sharp and the change in grain size across the boundary is abrupt. The rock under thin section shows undeformed igneous textures. Rare earth element patterns and isotopic compositions of Sr and Nd suggest that the central Tarim diorite was derived from an arc setting. The minimum age of the diorite is determined by 40Ar/ 39Ar dating of hornblende, which yields three ages from three different samples: 790.0±22.1, 754.4±22.6, and 744.0±9.3 Ma, respectively (uncertainty is reported at 1 σ). The older age is associated with the fine-grained sample while the younger ages are associated with the medium-grained samples. We are unable to determine whether the different ages are due to argon loss as the rock was located in partial retention zone or caused by different phases of igneous

  4. Active tectonics of the Atacama Basin area, northern Chile: Implications for distribution of convergence across the central Andes

    NASA Astrophysics Data System (ADS)

    Chuang, Yi-Rung; Lin, Yen-Sheng; Shyu, J. Bruce H.

    2013-04-01

    The central Andes in South America is formed as the Nazca plate subducts northeastward beneath the South American plate along the Peru-Chile trench, parallel to the coastline. It has been shown that the convergence rate between the two plates is ~70-80 mm/yr, and about 10-15 mm/yr of the convergence is absorbed in the sub-Andean belt, east of the active volcanic arc. However, the convergence in the forearc region is still not well constrained. In order to understand how much convergence is absorbed in the forearc region, we analyzed the active tectonic characteristics of the Atacama Basin, just west of the active volcanic arc. With the help of various remote sensing datasets such as 30-m and 90-m resolution digital elevation models (DEM) produced from SRTM data, thermal infrared radiometer (TIR) ASTER images, Landsat, and Google Earth images, we identified many N-S trending compressional structures around the Atacama Basin. The active structures are found mainly in the northern and southern part of the basin. The structures in the north deformed many volcanic rocks at the surface, such as ignimbrites and several lava flows. Structures may extend southward to San Pedro de Atacama, the largest town in the Atacama Basin, and produced tectonic scarps inside the town. River terraces also formed in the hanging-wall block of the structures, north of San Pedro. From field surveys, we measured the offset amount of the structures and collected volcanic rocks in order to constrain the age of the deformation. These results enabled us to calculate the long-term deformation rate of the structures. Our results indicate that the long-term slip rate of the structures in the southern part of the basin is quite low, in the order of 10-1 mm/yr. Furthermore, we obtained detailed topographic profiles across the structures. In the south, the profiles were surveyed by using real-time kinematic (RTK) GPS. Together with the attitudes of bedding planes, we constructed the subsurface geometry

  5. Hydrological response to forest disturbance under a changing climate in experimental headwater basins, Central Sumava Mountains

    NASA Astrophysics Data System (ADS)

    Su, Ye; Gao, Hongkai; Langhammer, Jakub; Savenije, Hubert H. G.

    2014-05-01

    In forested basins, forest disturbance and climatic variability are commonly recognized as two major drivers of hydrological regimes changes. Vydra's mountainous headwater basin in the Czech Republic, which is selected as study area, has undergone simultaneously an increase in temperature and extensive forest disturbance mainly resulting from bark beetle outbreak. The study area consists of 8 small experimental sub-basins of size around 3-5 km2. Water stages have been monitored in 10-min interval since 2005. Data on precipitation, air temperature, radiation, air humidity, wind speed and direction exist at 10-minute interval, in 4 stations since 2009. Different sub-basins are covered by different types of physiographic conditions, land cover and varying intensity and nature of forest disturbance. A paired basin methodology was used to study the effect of land cover change on the runoff regime. In the studied basins, the cumulative effects of the changing climate and the extensive forest decay are reflected in the observed discharge data in terms of the seasonal shift in peak flow and low flow magnitude, frequency, and duration by statistical methods. From the basin comparison, we could identify which factors determine the differences in hydrological regimes adjustment. Two main conclusions can be drawn: 1) forest disturbance largely changes the interception and transpiration, and 2) paired basins method is able to trade time for space in understanding the process of forest degradation and regeneration, especially in the growing season. In winter the hydrological regime shifts were mainly driven by climate variability. Subsequently, we used this knowledge in hydrological models and tested our hypothesis by stepwise modelling. We assume that the topography and land cover have great influence on the hydrological regime under different climate conditions. Thus, we test the split-sample validation as well as model transferability within the framework of the FLEX

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Shelf to basin transition of Silurian-Devonian rocks, Porcupine River area, east-central Alaska

    SciTech Connect

    Colean, D.A.

    1985-04-01

    Exposures of Silurian to lowermost Devonian strata in the Porcupine River region consist of an unnamed carbonate unit and the Road River Formation. Petrographic studies indicate that these rocks display facies representative of five depositional environments: basin, open sea shelf, deep shelf margin, open platform, and restricted shelf. The unnamed carbonate unit, exposed in the Linear Ridge area, is 390 ft (126 m) thick and records a history of restricted shelf to basinal sedimentation. Stratigraphic relations and paleontological studies suggest a Middle to Late Silurian (Ludlovian) age for this unit. The Road River Formation is Late Silurian (Ludlovian) to Early Devonian (Lochkovian) in age and is exposed near the confluence of the Porcupine-Salmontrout Rivers and downstream along the Lower Ramparts. It consists of 30-190 ft (10-61 m) of graptolitic shale with interbeds of siliceous limestone. Petrographic studies of the shales are interpreted to reflect deposition in a basinal setting, whereas the siliceous limestones represent deep shelf-margin debris flows derived from nearby, coeval shallow-water shelf environments. Together, the unnamed carbonate unit and the Road River Formation represent a shelf to basin transition on a carbonate ramp that transcends the Silurian-Devonian boundary. Petrographic examination of these rocks reveals that they are susceptible to a wide range of diagenetic processes, including (1) micritition, (2) neomorphism, (3) syntaxial overgrowths, (4) pressure solution (stylolitization), (5) trapping of dried hydrocarbons, (6) tensional stress (calcite veining), and (7) silicification.

  15. 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...

  16. 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...

  17. 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.

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

    USGS Publications Warehouse

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

    2015-07-30

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

  19. 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.

  20. 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

  1. 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.

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. The Albuquerque Indian School: Culture, Environment and Change.

    ERIC Educational Resources Information Center

    Taylor, Anne; Swentzel, Rina

    1979-01-01

    The architectural renovation project at Albuquerque Indian School not only reclaimed dilapidated buildings but involved students and community in planning their learning environment and taught students practical career skills, such as plumbing, landscape and interior design, and woodworking. This article is part of a theme issue on multicultural…

  7. 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

  8. 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

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

    USGS Publications Warehouse

    Chesnut, D.R.

    1997-01-01

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

  10. 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

  11. Selection of prey by walleyes in the Ohio waters of the central basin of Lake Erie, 1985-1987

    USGS Publications Warehouse

    Wolfert, David R.; Bur, Michael T.

    1992-01-01

    Walleyes (Stizostedion vitreum vitreum) were collected at five locations in the central basin of Lake Erie in 1985-87. The contents of the fishes' stomachs were examined to identify the species of prey. The seasonal availability of potential prey was determined from sampling with trawl tows. Food electivity indexes for young-of-the-year (YOY) and older walleyes were calculated. Electivity indexes changed monthly in YOY walleyes that consumed mostly YOY gizzard shads (Dorosoma cepedianum) in July and fed moderately on gizzard shads, but more on smelts (Osmerus mordax), in August. In September and October YOY walleyes did not consume YOY white perch (Morone americana). During October, they continued to eat YOY gizzard shads moderately but consumed mostly emerald shiners (Notropis atherinoides). Older walleys were highly partial to YOY gizzard shads, emerald shiners, and smelts and consumed no YOY white perch. The numbers of YOY yellow perch (Perca flavescens) in stomachs were limited. Prey selection by walleyes in the central basin was species-specific irrespective of abundance of prey.

  12. 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.

  13. 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.

  14. 76 FR 10389 - Reopening the Call for Nominations for the New Mexico Albuquerque and Farmington District...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-24

    ... Bureau of Land Management Reopening the Call for Nominations for the New Mexico Albuquerque and... (BLM) Albuquerque, New Mexico, and Farmington, New Mexico, Resource Advisory Councils (RAC). The RACs... within the Albuquerque and Farmington Districts. The Farmington, New Mexico, RAC is only...

  15. 40 CFR 81.83 - Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Albuquerque-Mid Rio Grande Intrastate... Designation of Air Quality Control Regions § 81.83 Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region. The Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region (New Mexico) is revised...

  16. 40 CFR 81.83 - Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Albuquerque-Mid Rio Grande Intrastate... Designation of Air Quality Control Regions § 81.83 Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region. The Albuquerque-Mid Rio Grande Intrastate Air Quality Control Region (New Mexico) is revised...

  17. Summary of Flow Loss between Selected Cross Sections on the Rio Grande in and near Albuquerque, New Mexico

    USGS Publications Warehouse

    Veenhuis, Jack E.

    2002-01-01

    The upper middle Rio Grande Basin, as defined by the U.S. Army Corps of Engineers, extends from the headwaters of the Rio Grande in southwestern Colorado to Fort Quitman, Texas. Most of the basin has a semiarid climate typical of the southwestern United States. This climate drives a highly variable streamflow regime that contributes to the complexity of water management in the basin. Currently, rapid population growth in the basin has resulted in increasing demands on the hydrologic system. Water management decisions have become increasingly complex because of the broad range of interests and issues. For these reasons, the U.S. Geological Survey, in cooperation with the City of Albuquerque, New Mexico, conducted paired flow measurements at two cross sections to determine cross-sectional loss in the Albuquerque reach of the Rio Grande. This report statistically summarizes flow losses in the Albuquerque reach of the Rio Grande during the winter nonirrigation season from December 1996 to February 2000. The two previous flow-loss investigations are statistically summarized. Daily mean flow losses are calculated for the winter nonirrigation season using daily mean flows at three selected Rio Grande streamflow-gaging stations.For the winter nonirrigation season cross-sectional measurements (1996-2000), an average of 210 cubic feet per second was returned to the river between the measurement sites, of which 165 cubic feet per second was intercepted by riverside drains along the 21.9-mile reach from the Rio Grande near Bernalillo to the Rio Grande at Rio Bravo Bridge streamflow-gaging stations. Total cross-sectional losses in this reach averaged about 90 cubic feet per second. Regression equations were determined for estimating downstream total outflow from upstream total inflow for all three paired measurement studies. Regression equations relating the three daily mean flow recording stations also were determined. In each succeeding study, additional outside variables

  18. Surface water of Beaver Creek Basin, in South-Central Oklahoma

    USGS Publications Warehouse

    Laine, L.L.; Murphy, J.J.

    1962-01-01

    Annual discharge from Beaver Creek basin is estimated to have averaged 217,000 acre-feet during a 19-year base period, water years 1938-56, equivalent to an average annual runoff depth of 4.7 inches over the 857 square-mile drainage area. About 55,000 acre-feet per year comes from Little Beaver Creek basin, a tributary drainage of 195 square miles. Yearly streamflow is highly variable. The discharge of Little Beaver Creek near Duncan during 13-year period of record (water years 1949-61) has ranged from 86,530 acre-feet in calendar year 1957 to 4,880 acre-feet in 1956, a ratio of almost 18 to 1. Highest runoff within a year tends to occur in the spring months of May and June, a 2-month period that, on the average, accounts for more than half of the annual discharge of Little Beaver Creek near Duncan. The average monthly runoff during record was lowest in January. Variation in daily streamflow is such that while the average discharge for the 13-year period of record was 50.1 cfs (cubic feet per second), the daily discharge was more than 6 cfs only about half of the time. There was no flow at the site 19 percent of the time during the period. Some base runoff usually exists in the headwaters of Beaver and Little Beaver Creeks, and in the lower reaches of Beaver Creek. Low flow in Cow Creek tends to be sustained by waste water from Duncan, where water use in 1961 averaged 4 million gallons per day. In the remainder of the basin, periods of no flow occur in most years. The surface water of Beaver Creek basin is very hard but in general is usable for municipal, agricultural and industrial purposes. The chemical character of the water is predominantly a calcium, magnesium bicarbonate type of water in the lower three quarters of the basin, except in Cow Creek where oil-field brines induce a distinct sodium, calcium chloride characteristic at low and medium flows. A calcium sulfate type of water occurs in most of the northern part of the basin except in headwater areas

  19. 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.

  20. 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

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

    USGS Publications Warehouse

    Bultman, Mark W.; Page, William R.

    2016-10-31

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

  2. Surface water of Muddy Boggy River basin in south-central Oklahoma

    USGS Publications Warehouse

    Westfall, A.O.; Cummings, T. Ray

    1963-01-01

    This report summarizes basic hydrologic data of the surface water resources of Muddy Boggy River basin, and by analysis and interpretation, presents certain streamflow characteristics at specified points in the basin. Muddy Boggy River has a drainage area of 2,429 square miles. The climate is moist subhumid and the annual precipitation averages about 39 inches. Gross annual lake evaporation averages 54 inches. The average annual discharge at the gaging stations for the period 1938-62 was 24,000 acre-feet for Chickasaw Creek near Stringtown; 72,000 acre-feet for McGee Creek near Stringtown; 671,800 acre-feet for Muddy Boggy Creek near Farris; and 358,200 acre-feet for Clear Boggy Creek near Caney. Flow-duration curves of daily discharge have been developed to show the percentage of time various rates of discharge have been equaled or exceeded. Procedures for determining the frequency of annual floods at any point in the basin are given. Low-flow frequency curves that define the recurrence intervals of 7, 14, 30, 60, and 120 day mean flows have been prepared for two gaging stations. Curves showing the relation of measured discharge at the low-flow partial-record stations to the daily mean discharge at a base gaging station are presented. Discharge measurements made in February 1963 at selected sites show the areal distribution of low flow. The storage requirements to supplement natural flows have been prepared for two gaging-stations sites. The chemical quality of surface water of Muddy Boggy River basin varies from place-to-place during base flow periods. Limestone and dolomite outcrops and oilfield brines affect water quality in some areas. Water of North Boggy Creek, McGee Creek, and their tributaries contains less than 100 ppm (parts per million) dissolved solids. Water of other streams in Muddy Boggy River basin has a higher dissolved-solids content, but the content does not exceed 500 ppm. Water of Muddy Boggy River basin is usable for domestic, irrigation, and

  3. U-Pb Detrital Zircon Geochronology and Implications: the Mesozoic southern Ordos Basin, North Central China

    NASA Astrophysics Data System (ADS)

    Xie, X.; Heller, P. L.; Chamberlain, K. R.

    2007-12-01

    Two deformation belts -- the Qinling orogenic belt (QOB) to the south and the Western Liupanshan thrust belt (WLTB) to the west, including the Qilian-Qaidam terrane (QQT) -- control the evolution of the southern Ordos Basin during early Mesozoic time. U-Pb detrital zircon geochronology is used to identify provenance, reconstruct paleogeography, and document the relative timing of basin margin deformation. Two correlated strata same age samples of the Middle to Late Triassic Yanchang Fm. were collected from the southern and southwestern basin margin respectively. In total 258 zircon grains were analyzed using LA-ICP-MS. Three major age populations -- 240-490 Ma, 1.8-2.0 Ga, and 2.2-2.8 Ga -- characterize the detrital zircon grains of the Yanchang Fm. Regional geochronology studies show that the two oldest age groups match ages of basement rocks found in the underlying North China block. The younger age group can be subdivided into three distinctive groups: 240-300 Ma, 300-400, and 400-490 Ma. The youngest age group matches ages exposed to the west in the QQT, whereas the other two match grains from southern QOB source. In all samples detrital zircon from the WLTB source area overwhelms the QOB source, regardless of its proximity to either basin margin. This result suggests that either the source rock with the youngest zircon grains (e.g. 240- 490 Ma) from the QOB to the south have been eroded away and no longer existed, or simply the QOB, even during deformation, was never the dominant source of detrital zircon to the southern Ordos Basin. Probably some drainage systems far from the west combine with some local tributary systems from the south control the sedimentation in the south Ordos Basin during the middle to Late Triassic time. This is surprising in that most studies suggest that the QOB was a longer lived and more dominant tectonic feature in this part of China during early Mesozoic time. Furthermore, it also indicates that: 1) deformation in the QOB and WLTB

  4. 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

  5. Inversion tectonics in the Anayet Permian basin (Axial Zone, Central Pyrenees)

    NASA Astrophysics Data System (ADS)

    Rodriguez, L.; Cuevas, J.; Tubía, J. M.

    2012-04-01

    During Permian times the Pyrenees were characterized by extensional tectonics that opened subsident basins with pull-apart geometries. The Anayet Permian basin crops out in the western Spanish Axial Zone between the Aragon and Tena valleys. It is WNW-trending and it is filled by a continental Permian succession that represents the first post-variscan deposits in the area. Permian deposits rest discordantly over Devonian to Carboniferous limestones, sandstones and slates. In the Anayet basin, Permian deposits have been classically divided in four main detrital groups, mainly composed of sandstones and conglomerates, with three basic volcanic episodes interbedded (Gisbert, 1984, Bixel, 1987). Due to the lithological characteristics of the Permian rocks in this region, there are almost no accurate age constraints for these units. A detailed structural study of the area, including mapping and balanced cross-sections, shows increasingly older rocks to the west of the Anayet basin. Moreover, it can be deduced a mean slope of around 11 % to the west for the basin. These data confirm that the basin depocenter was located to the west and that the Anayet basin was partitioned by N10 °E-trending normal faults. Although the contacts between the Permian and the Devono-Carboniferous rocks are covered by quaternary deposits in most of its extent, a fault contact can also be recognized. The fault contact is a 3 m thick shear zone oriented N120 ° E and dipping 60° to the North. It develops breccias, fault gouges and sigmoidal S-C tectonites indicating a reverse motion. The contact places Permian slates and sandstones over Carboniferous limestones and is almost parallel to the alpine cleavage deforming Permian rocks. The slope of the contact together with the presence of younger rocks in the hangingwall of the reverse fault points out that the original contact was a normal fault reactivated as a high-angle reverse fault during the positive inversion tectonics induced by the

  6. 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

  7. 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

  8. Surface-water/ground-water relations in the Lemhi River Basin, east-central Idaho

    USGS Publications Warehouse

    Donato, Mary M.

    1998-01-01

    This report summarizes work carried out in cooperation with the Bureau of Reclamation to provide hydrologic information to help Federal, State, and local agencies meet the goals of the Lemhi River Model Watershed Project. The primary goal of the project is to maintain, enhance, and restore anadromous and resident fish habitat in the Lemhi River, while maintaining a balance between resource protection and established water uses. The main objectives of the study were to carry out seepage measurements to determine seasonal distributed gains and losses in the Lemhi River and to estimate annual ground-water underflow from the basin to the Salmon River. In 1997, seepage measurements were made during and after the irrigation season along a 60-mile reach of the Lemhi River between Leadore and Salmon. Except for one 4-mile reach that lost 1.3 cubic feet per second per mile, the river gained from ground water in early August when ground-water levels were high. Highest flows in the Lemhi River in early August were about 400 cubic feet per second. In October, when ground-water levels were low, river losses to ground water were about 1 to 16 cubic feet per second per mile. In October, highest flows in the Lemhi River were about 500 cubic feet per second, near the river's mouth. Annual ground-water underflow from the Lemhi River Basin to the Salmon River was estimated by using a simplified water budget and by using Darcy's equation. The water-budget method contained large uncertainties associated with estimating precipitation and evapotranspiration. Results of both methods indicate that the quantity of ground water leaving the basin as underflow is small, probably less than 2 percent of the basin's total annual water yield.

  9. Petrofacies and provenance of late mesozoic forearc basin, northern and central California

    SciTech Connect

    Ingersoll, R.V.

    1983-07-01

    Data from the Great Valley Group (sequence) represent the most complete information regarding sandstone petrology of sediment derived from a magmatic arc. This information is useful in documenting tectonic and magmatic events within the arc and related terranes, and forms the basis for the establishment of petrostratigraphic units for mapping and correlation. Sandstone and conglomerate compositions are controlled by changes in provenance, many of which were basinwide and synchronous. Claymineral composition is controlled primarily by burial metamorphism. Careful attention to sample collection, sample preparation, and petrographic techniques is essential for uniform results. Seven petrographic parameters (P/F,Lv/L,M,Qp/Q,Q,F, and L-listed in decreasing importance to petrofacies discrimination) define eight petrofacies (Stony Creek, Platina, Lodoga, Grabast, Boxer, Cortina, Los Gatos and Rumsey-listed in approximate order of decreasing age). As the volcanic cover was stripped off, plutoniclastic and metamorphiclastic detritus from the underlying batholithic terranes was provided in abundance to the forearc basin. Crustal components were more ''continental'' in the southern Sierra Nevada and more ''oceanic'' in the northern Sierra Nevada, as demonstrated by the higher proportions of metamorphiclastic detritus and by the more felsic nature of volcaniclastic detritus to the south. By the middle of the Late Cretaceous, extensive batholithic terranes provided potassium-feldspar-rich arkosic detritus to the entire forearc basin. By the Paleogene, arc magmatism had migrated eastward sufficiently that deeper levels of the California part of the arc were exposed by erosion, tectonic activity decreased in the forearc basin, and the basin was filled to sea level in most parts.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. Shallow structure and its formation process of an active flexure in the forearc basin of the central Nankai subduction zone

    NASA Astrophysics Data System (ADS)

    Ashi, J.; Ikehara, K.; Omura, A.; Ojima, T.; Murayama, M.

    2013-12-01

    ENE-WSW trending active faults, named Enshu fault system, are developed in the forearc basins of the eastern and central Nankai subduction zone. Three parallel faults developed in the Enshu forearc basin of the eastern Nankai have right lateral slip on the basis of dextral displacement of the canyon axis. Moreover, bathymetry data and side-scan sonar imageries indicate relative uplift of the northern region and the multichannel seismic (MCS) reflection profiles show northward dipping fault planes. In the central Nankai subuduction zone, an ENE-WSW trending step is distributed at the northern part of the Kumano forearc basin and is regarded as the western extension of the Enshu fault system. Although MCS records show deformations including an anticlinal fold beneath the bathymetric step, they have less resolution to identify deformation of basin sequence just below the seafloor. In contrast, deformation seems to reach to the seafloor on a profile by SBP mounted on a mother ship. Investigation of shallow deformation structures is significant for understanding of recent tectonic activity. We carried out deep towed SBP survey by ROV NSS (Navigable Sampling System) during Hakuho-maru KH-11-9 cruise. High resolution mapping of shallow structures was successfully conducted by a chirp SBP system of EdgeTech DW-106. ROV NSS also has capability to take a long core with a pinpoint accuracy around complex topographic region. The Kumano forearc basin is topographically divided into the northern part at a water depth of 2038 m and the other major region at a depth of 2042 m by the ENE-WSW linear step. Three deep towed SBP lines intersected this topographical step and revealed the following structures. This step is composed of 100 m wide gentle slope with an inclination of about 8 degrees. An anticlinal axis is located beneath the upper edge of this slope. Sedimentary layers continue at this slope region without any abut/termination and rapidly increase their thickness toward the

  15. Instream flow characterization of upper Salmon River Basin streams, Central Idaho, 2003

    USGS Publications Warehouse

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2004-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream from the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the federally listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications, as a result of irrigation practices, have directly affected the quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include the collection of habitat and streamflow information for the Physical Habitat Simulation (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model results can be used by resource managers to guide habitat restoration efforts in the evaluation of potential fish habitat and passage improvements by increasing streamflow. Instream flow characterization studies were completed on Pole, Fourth of July, Elk, and Valley Creeks during 2003. Continuous streamflow data were collected upstream from all diversions on each stream. In addition, natural summer streamflows were estimated for each study site using regression

  16. Relation between ground water and surface water in the Hillsborough River basin, west-central Florida

    USGS Publications Warehouse

    Wolansky, R.M.; Thompson, T.H.

    1987-01-01

    The relation between groundwater and surface water in the Hillsborough River basin was defined through the use of: seismic-reflection profiling along selected reaches of the Hillsborough River, and evaluation of streamflow, rainfall, groundwater levels, water quality, and geologic data. Major municipal well fields in the basin are Morris Bridge and Cypress Creek where an averages of 15.3 and 30.0 million gal/day (mgd), respectively, were pumped in 1980. Mean annual rainfall for the study area is 53.7 inches. Average rainfall for 1980, determined from eight rainfall stations, was 49.7 inches. Evapotranspiration, corrected for the 5% of the basin that is standing water, was 35.7 in/year. The principal geohydrologic units in the basin are the surficial aquifer, the intermediate aquifer and confining beds, the Upper Floridan aquifer, the middle confining unit, and the Lower Floridan aquifer. Total pumpage of groundwater in 1980 was 98.18 mgd. The surficial aquifer and the intermediate aquifer are not used for major groundwater supply in the basin. Continuous marine seismic-reflection data collected along selected reaches of the Hillsborough River were interpreted to define the riverbed profile, the thickness of surficial deposits, and the top of persistent limestone. Major areas of groundwater discharge near the Hillsborough River and its tributaries are the wetlands adjacent to the river between the Zephyrhills gaging stations and Fletcher Avenue and the wetlands adjacent to Cypress Creek. An estimated 20 mgd seeps upward from the Upper Floridan aquifer within those wetland areas. The runoff/sq mi is greater at the Zephyrhills station than at Morris Bridge. However, results of groundwater flow models and potentiometric-surface maps indicate that groundwater is flowing upward along the Hillsborough River between the Zephyrhills gage and the Morris Bridge gage. This upward leakage is lost to evapotranspiration. An aquifer test conducted in 1978 at the Morris Bridge well

  17. 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

  18. Impact of climate Change on Groundwater Recharge in the Tiber River Basin (Central Italy) Using Regional Climate model Outputs

    NASA Astrophysics Data System (ADS)

    Muluneh, F. B.; Setegn, S. G.; Melesse, A. M.; Fiori, A.

    2011-12-01

    Quantification of the various components of hydrological processes in a watershed remains a challenging topic as the hydrological system is altered by many internal and external drivers. Changes in climate variables can affect the quantity and quality of various components of hydrological cycle. Among others, the local effects of climate change on groundwater resources were not fully studied in different part of the world as compared to the surface water. Moreover, understanding the potential impact of climate change on groundwater is more complex than surface water. The main objective of this study is to analyze the potential impact of climate change on Groundwater recharge in the Tiber River Basin using outputs from Regional Climate model. In this study, a physically-based watershed model called Soil Water Assessment Tool (SWAT) was used to estimate recharge characteristics and its response to climate change in Tiber River Basin (central Italy). The SWAT model was successfully calibrated and validated using observed weather and flow data for the period of 1963-1970 and 1971-1978 respectively. During calibration, the model was highly sensitivity to groundwater flow parameters. Dynamically downscaled rainfall and temperature datasets from ten Regional Climate Models (RCM) archived in 'Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects (PRUDENCE)' were used to force the model to assess the climate change impact on the study area. A quantile-mapping statistical correction procedure was applied to the RCM dataset to correct the inherent systematic biases. The climate change analysis indicated that by the end of 2080s the rainfall was found to decrease nearly up to 40% in dry period and there was an increase in temperature that could reach as high as 3 to 5 oC. By the end of 2080s the ground water recharge shows a decreasing trend as a response to changes in rainfall. However as the timing of both precipitation and

  19. Reconnaissance geochronology of tuffs in the Miocene Barstow Formation: implications for basin evolution and tectonics in the central Mojave Desert

    USGS Publications Warehouse

    Miller, D.M.; Leslie, S.R.; Hillhouse, J.W.; Wooden, J.L.; Vazquez, J.A.; Reynolds, R.E.

    2010-01-01

    Early to middle Miocene lacustrine strata of the Barstow Formation are well dated in just a few places, limiting our ability to infer basin evolution and regional tectonics. At the type section in the Mud Hills, previous studies have shown that the lacustrine interval of the Barstow Formation is between ~16.3 Ma and ~13.4 Ma. Elsewhere, lake beds of the Barstow Formation have yielded vertebrate fossils showing the Hemingfordian/Bartovian transition at ~16 Ma but are otherwise poorly dated. In an attempt to clarify the age and depositional environments of the lake deposits, we are mapping the Barstow Formation and dating zircons from interbedded tuffs, as well as testing ash-flow tuffs for the distinctive remanent magnetization direction of the widespread Peach Spring Tuff. Thus far, our new U-Pb zircon ages inficate that the Barstow lake beds contain tuff beds as old as 19.1 Ma and as young as 15.3 Ma. At Harvard Hill, Barstow lake beds contain a thick tuff dated at 18.7 Ma. On the basis of zircon ages, mineralogy, zircon chemistry, and paleomagnetic results, we consider the thick tuff to be a lacustrine facies of the Peach Spring Tuff. We have identified the Peach Spring Tuff by similar methods at eight localities over a broad area, providing a timeline for several fluvial and lacustrine sections. The new dates indicate that long-lived lacustrine systems originated before 19 Ma and persisted to at least 15 Ma. The onset of lacustrine conditions predates the Peach Spring Tuff in most Barstow Formation sections and may be older than 19.5 Ma in some places. The new data indicate that the central Mojave Desert contained narrow to broad lake basins during and after extension, and that Barstow lacustrine deposits did not exclusively postdate extensional tectonics. At present, it is unclear whether several separate, small lake basins coexisted during the early to middle Miocene, or if instead several small early Miocene basins gradually coalesced over about 6 millions

  20. Reconnaissance geochronology of tuffs in the Miocene Barstow Formation: implications for basin evolution and tectonics in the central Mojave Desert

    USGS Publications Warehouse

    Miller, David M.; Leslie, Shannon R.; Hillhouse, John W.; Wooden, Joseph L.; Vazquez, Jorge A.; Reynolds, R.E.

    2010-01-01

    Early to middle Miocene lacustrine strata of the Barstow Formation are well dated in just a few places, limiting our ability to infer basin evolution and regional tectonics. At the type section in the Mud Hills, previous studies have shown that the lacustrine interval of the Barstow Formation is between ~16.3 Ma and ~13.4 Ma. Elsewhere, lake beds of the Barstow Formation have yielded vertebrate fossils showing the Hemingfordian/Barstovian transition at ~16 Ma but are otherwise poorly dated. In an attempt to clarify the age and depositional environments of the lake deposits, we are mapping the Barstow Formation and dating zircons from interbedded tuffs, as well as testing ash-flow tuffs for the distinctive remanent magnetization direction of the widespread Peach Spring Tuff. Thus far, our new U-Pb zircon ages indicate that the Barstow lake beds contain tuff beds as old as 19.1 Ma and as young as 15.3 Ma. At Harvard Hill, Barstow lake beds contain a thick tuff dated at 18.7 Ma. On the basis of zircon ages, mineralogy, zircon chemistry, and paleomagnetic results, we consider the thick tuff to be a lacustrine facies of the Peach Spring Tuff. We have identified the Peach Spring Tuff by similar methods at eight localities over a broad area, providing a timeline for several fluvial and lacustrine sections. The new dates indicate that long-lived lacustrine systems originated before 19 Ma and persisted to at least 15 Ma. The onset of lacustrine conditions predates the Peach Spring Tuff in most Barstow Formation sections and may be older than 19.5 Ma in some places. The new data indicate that the central Mojave Desert contained narrow to broad lake basins during and after extension, and that Barstow lacustrine deposits did not exclusively postdate extensional tectonics. At present, it is unclear whether several separate, small lake basins coexisted during the early to middle Miocene, or if instead several small early Miocene basins gradually coalesced over about 6 million

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Natural denitrification in the Kakamigahara groundwater basin, Gifu prefecture, central Japan.

    PubMed

    Mohamed, Mohamed A A; Terao, H; Suzuki, Ryo; Babiker, Insaf S; Ohta, Keiichi; Kaori, K; Kato, Kikuo

    2003-05-20

    Although nitrate is recognized as the most common groundwater contaminant due to growing anthropogenic sources, such as agriculture in particular, its adverse effects on human and animal health are debatable. The current issue, however, is to control and reduce nitrate contamination with regards to the long residence time of groundwater within aquifers. Denitrification has recently been recognized for its ability to reduce high nitrate concentrations in groundwater. The Kakamigahara groundwater basin, Gifu prefecture, Japan, witnessed rising levels of nitrate (>12 mg/l NO(3)-N) originating from agricultural sources. Chemical analyses for the determination of major constituents of groundwater and delta(15)N of residual nitrate were performed on representative groundwater samples in order to fulfill two main objectives. One is to investigate the current situation of nitrate groundwater pollution. The second objective is to determine whether the denitrification is a potential natural mechanism, which eliminates nitrate pollution in the Kakamigahara aquifer. Agricultural nitrate contamination of groundwater was obvious from characteristically high concentrations of Ca(2+), Mg(2+), NO(3)(-) and SO(4)(2-). High nitrate concentrations were found on the eastern side of the basin in association with vegetable cultivation fields, and decreased gradually towards the west of the basin along the direction of groundwater flow. The decrease of nitrate concentration was conveniently coupled with increase of HCO(3)(-) (the heterotrophic denitrification product), pH and delta(15)N of residual nitrate (due to isotopic fractionation) from east to west. Therefore, denitrification in situ is continuously removing nitrate from the Kakamigahara groundwater system.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.; Ruppert, Leslie F.; Ryder, Robert T.

    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.

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

    USGS Publications Warehouse

    Leonard, Robert B.; Kleinschmidt, Melvin K.

    1976-01-01

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

  13. Uncertainties in the stratigraphic analysis of fluvial deposits from the Loranca Basin, central Spain

    NASA Astrophysics Data System (ADS)

    Daams, R.; Díaz-Molina, M.; Mas, R.

    1996-03-01

    A detailed stratigraphic and sedimentological analysis is given of Late Oligocene to Early Miocene continental sediments in a small area (1 km 2) of the Loranca Basin (Province of Cuenca). The studied exposure is a part of the Tórtola fluvial fan and mainly consists of superimposed meander belt sediments. The ages of base and top of the sedimentary succession were obtained by a combination of biostratigraphic and palaeomagnetic data, thus allowing us to estimate the mean sedimentation rates of the section (10 cm/ka). Our estimation of the sediment accumulation rate based on the analysis of palaeosols (18 cm/ka) appears to be reasonably reliable for short-term accumulation rates. The small size of palaeochannels and the relatively wide basin section may have allowed the development of a distributary fluvial system and may have caused the low vertical recurrence of relatively episodic sedimentation. The time interval covered by the sediments studied shows a progressive trend toward drier conditions and higher temperatures, inferred from qualitative and quantitative changes in fossil rodent faunas. These trends coincide with a gradual decrease of maximum values of estimated discharge of our fluvial systems. In these sediments it is dangerous to establish a correlation between the detected possible climatic changes and Milankovitch cycles. This is due to the low sedimentation rate and the frequent discontinuities in our stratigraphic record.

  14. Multisource remote sensing supported large scale fully distributed hydrological modeling of the Tarim River Basin in Central Asia

    NASA Astrophysics Data System (ADS)

    Feng, Xianwei; Chen, Xi; Willems, Patrick; Liu, Tie; Li, Lanhai; Bao, Anming; Huang, Yue

    2009-06-01

    Potential application of remote sensing in hydrology is one of the hot spots in the distributed hydrological model research. The remote sensing technology can be applied to obtain the spatial distribution and dynamics of hydrological phenomena which is not generally possible based on traditional data. In this paper, a fully distributed large scale hydrological modeling application is considered in the semi-arid area of the River Tarim basin in central Asia (area of more than 1.20x105 km2). The model has been built based on the hydrological modeling software MIKE-SHE, which makes combined use of ground station data and multi-source and multi-temporal remote sensing data. Input and output data of spatially and temporally detailed variable model have been obtained by remote sensing data processing and geographical* spatial analysis for many useful hydrologic variables. These variables include digital elevations, land uses, soil types, precipitation intensities, evapotranspiration depths, snow cover heights and areas and leaf area index information. Through the case study application, insights have been obtained in the advantage of the potential usage of the remote sensing technology and products to support the hydrological process modeling of large scale river basins in developing countries where traditional station based data is very limited. The technology developed and the experience built in this study can be exported for applications in other analogical regions.

  15. 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.

  16. 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.

  17. 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.

  18. Instream flow characterization of Upper Salmon River basin streams, central Idaho, 2005

    USGS Publications Warehouse

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2006-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream of the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the ESA-listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications resulting from irrigation practices, have directly affected quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include collection of habitat and streamflow information for the Physical Habitat Simulation System (PHABSIM) model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model simulation results can be used by resource managers to guide habitat restoration efforts by evaluating potential fish habitat and passage improvements by increasing or decreasing streamflow. In 2005, instream flow characterization studies were completed on Big Boulder, Challis, Bear, Mill, and Morgan Creeks. Continuous streamflow data were recorded upstream of all diversions on Big Boulder. Instantaneous measurements of discharge were also made at selected sites. In

  19. Instream flow characterization of upper Salmon River basin streams, central Idaho, 2004

    USGS Publications Warehouse

    Maret, Terry R.; Hortness, Jon E.; Ott, Douglas S.

    2005-01-01

    Anadromous fish populations in the Columbia River Basin have plummeted in the last 100 years. This severe decline led to Federal listing of Chinook salmon (Oncorhynchus tshawytscha) and steelhead trout (Oncorhynchus mykiss) stocks as endangered or threatened under the Endangered Species Act (ESA) in the 1990s. Historically, the upper Salmon River Basin (upstream of the confluence with the Pahsimeroi River) in Idaho provided migration corridors and significant habitat for these ESA-listed species, in addition to the ESA-listed bull trout (Salvelinus confluentus). Human development has modified the original streamflow conditions in many streams in the upper Salmon River Basin. Summer streamflow modifications resulting from irrigation practices, have directly affected quantity and quality of fish habitat and also have affected migration and (or) access to suitable spawning and rearing habitat for these fish. As a result of these ESA listings and Action 149 of the Federal Columbia River Power System Biological Opinion of 2000, the Bureau of Reclamation was tasked to conduct streamflow characterization studies in the upper Salmon River Basin to clearly define habitat requirements for effective species management and habitat restoration. These studies include collection of habitat and streamflow information for the Physical Habitat Simulation System model, a widely applied method to determine relations between habitat and discharge requirements for various fish species and life stages. Model results can be used by resource managers to guide habitat restoration efforts by evaluating potential fish habitat and passage improvements by increasing streamflow. In 2004, instream flow characterization studies were completed on Salmon River and Beaver, Pole, Champion, Iron, Thompson, and Squaw Creeks. Continuous streamflow data were recorded upstream of all diversions on Salmon River and Pole, Iron, Thompson, and Squaw Creeks. In addition, natural summer streamflows were

  20. 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

  1. Physical characteristics of stream subbasins in the Middle Minnesota - Little Cottonwood River Basin, south-central Minnesota

    USGS Publications Warehouse

    Sanocki, Christopher A.

    1997-01-01

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

  2. 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.

  3. 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.; 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.

  4. 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.

  5. Morphotectonic control of the Białka drainage basin (Central Carpathians): Insights from DEM and morphometric analysis.

    NASA Astrophysics Data System (ADS)

    Wołosiewicz, Bartosz

    2016-06-01

    The Białka river valley is directly related to a deep NNW-SSE oriented fault zone. According to the results of previous morphometric analyses, the Białka drainage basin is one of the most tectonically active zones in the Central Carpathians. It is also located within an area of high seismic activity. In this study Digital Elevation Model (DEM) based, morphometric analyses were used to investigate the morphotectonic conditions of the watershed. The results reveal the relationships between the main tectonic feature and the landforms within the research area. The lineaments, as obtained from the classified aspect map, seem to coincide with the orientation of the main structures as well as the trends revealed by the theoretical Riedel-Skempton shear model. Base-level and isolong maps support the conclusion that the Białka and Biały Dunajec fault zones exert a strong influence on the morphology of the adjacent area.

  6. Water-quality assessment of the Central Arizona Basins, Arizona and northern Mexico; environmental setting and overview of water quality

    USGS Publications Warehouse

    Cordy, Gail E.; Rees, Julie A.; Edmonds, Robert J.; Gebler, Joseph B.; Wirt, Laurie; Gellenbeck, Dorinda J.; Anning, David W.

    1998-01-01

    The Central Arizona Basins study area in central and southern Arizona and northern Mexico is one of 60 study units that are part of the U.S. Geological Survey's National Water-Quality Assessment program. The purpose of this report is to describe the physical, chemical, and environmental characteristics that may affect water quality in the Central Arizona Basins study area and present an overview of water quality. Covering 34,700 square miles, the study area is characterized by generally north to northwestward-trending mountain ranges separated by broad, gently sloping alluvial valleys. Most of the perennial rivers and streams are in the northern part of the study area. Rivers and streams in the south are predominantly intermittent or ephemeral and flow in response to precipitation such as summer thunderstorms. Effluent-dependent streams do provide perennial flow in some reaches. The major aquifers in the study area are in the basin-fill deposits that may be as much as 12,000 feet thick. The 1990 population in the study area was about 3.45 million, and about 61 percent of the total was in Maricopa County (Phoenix and surrounding cities). Extensive population growth over the past decade has resulted in a twofold increase in urban land areas and increased municipal water use; however, agriculture remains the major water use. Seventy-three percent of all water with drawn in the study area during 1990 was used for agricultural purposes. The largest rivers in the study area-the Gila, Salt, and Verde-are perennial near their headwaters but become intermittent downstream because of impoundments and artificial diversions. As a result, the Central Arizona Basins study area is unique compared to less arid basins because the mean surface-water outflow is only 528 cubic feet per second from a total drainage area of 49,650 square miles. Peak flows in the northern part of the study area are the result of snowmelt runoff; whereas, summer thunderstorms account for the peak flows in

  7. 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.

  8. Map and digital database of sedimentary basins and indications of petroleum in the Central Alaska Province

    USGS Publications Warehouse

    Troutman, Sandra M.; Stanley, Richard G.

    2003-01-01

    This database and accompanying text depict historical and modern reported occurrences of petroleum both in wells and at the surface within the boundaries of the Central Alaska Province. These data were compiled from previously published and unpublished sources and were prepared for use in the 2002 U.S. Geological Survey petroleum assessment of Central Alaska, Yukon Flats region. Indications of petroleum are described as oil or gas shows in wells, oil or gas seeps, or outcrops of oil shale or oil-bearing rock and include confirmed and unconfirmed reports. The scale of the source map limits the spatial resolution (scale) of the database to 1:2,500,000 or smaller.

  9. 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

  10. 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.; 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 systematic