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1

Death Valley TronaWestend  

E-print Network

Death Valley National Park Fort Irwin Death Valley Searles Valley TronaWestend Ridgecrest Searles Goldfield Lida Tempiute Gold Point Beatty Amargosa Valley Mercury Indian Springs PiocheCaselton Prince Chloride Sunrise Manor Spring Valley Moapa Valley Mojave National Preserve Lake Mead National Recreation

Laughlin, Robert B.

2

Death Valley, California  

NASA Technical Reports Server (NTRS)

This is an image of Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. The bright dots near the center of the image are corner refectors that have been set-up to calibrate the radar as the Shuttle passes overhead with the SIR-C/X-SAR system. The Jet Propulsion Laboratory alternative photo number is P-43883.

1994-01-01

3

Multivariate statistical analysis of arsenic and selenium concentrations in groundwaters from south-central Nevada and Death Valley, California  

Microsoft Academic Search

Arsenic and selenium concentrations along with the major solutes were measured in ground-waters sampled from springs in Pahranagat Valley and Ash Meadows, Nevada, Death Valley, California, and from wells from the Nevada Test Site and Yucca Mountain, Nevada. The multivariate statistical technique correspondence analysis was applied to the data to determine relationships between the groundwaters from these areas, the aquifer

Kevin H. Johannesson; Klaus J. Stetzenbach; David K. Kreamer; Vernon F. Hodge

1996-01-01

4

Death Valley California as seen from STS-59  

NASA Technical Reports Server (NTRS)

This oblique handheld Hasselblad 70mm photo shows Death Valley, near California's border with Nevada. The valley -- the central feature of Death Valley National Monument -- extends north to south for some 140 miles (225 kilometers). Hemmed in to the east by the Amargosa Range and to the west by the Panamints, its width varies from 5 to 15 miles (8 to 24 kilometers).

1994-01-01

5

Putting the "Death" in Death Valley Paul Withers  

E-print Network

Putting the "Death" in Death Valley Paul Withers In 1849, gold was discovered at Sutter's Mill of human suffering in a place they named Death Valley. [From here on, historical sources have a tendency of the rough map, continued due west to discover Death Valley... They were composed of three groups: thirty

Withers, Paul

6

Multivariate statistical analysis of arsenic and selenium concentrations in groundwaters from south-central Nevada and Death Valley, California  

NASA Astrophysics Data System (ADS)

Arsenic and selenium concentrations along with the major solutes were measured in ground-waters sampled from springs in Pahranagat Valley and Ash Meadows, Nevada, Death Valley, California, and from wells from the Nevada Test Site and Yucca Mountain, Nevada. The multivariate statistical technique correspondence analysis was applied to the data to determine relationships between the groundwaters from these areas, the aquifer materials and the As and Se concentrations, and to examine the relationships between As and Se and the other chemical parameters included in the statistical analysis. The correspondence analysis indicates that a strong relationship exists between chloride and Se in the groundwaters and that As is not associated with chloride. The strong association between chloride and Se suggests that Se behaves more conservatively than As in these oxygenated, circumneutral pH groundwaters. No strong association was observed between the As and/or Se concentrations of the groundwaters and the aquifer material with which these waters interact (i.e. regional Paleozoic carbonate aquifer, Tertiary tuffaceous volcanic rocks, and/or basin-fill deposits). However, it is likely that sampling of groundwaters from the various aquifers was insufficient to determine relationships between the aquifer materials and groundwater chemistry. Associations were observed between the groundwaters of the Nevada Test Site and Yucca Mountain regions and the groundwaters of the regional carbonate aquifer that discharge at Ash Meadows and Death Valley, suggesting mixing of these waters. Ground-water from the regional carbonate aquifer in Pahranagat Valley, which is upgradient from the Nevada Test Site, Yucca Mountain, Ash Meadows, and Death Valley, exhibited no association with groundwaters from these regions.

Johannesson, Kevin H.; Stetzenbach, Klaus J.; Kreamer, David K.; Hodge, Vernon F.

1996-04-01

7

77 FR 33237 - Saline Valley Warm Springs Management Plan/Environmental Impact Statement, Death Valley National...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Valley Warm Springs Management Plan, Death Valley...Valley Warm Springs Management Plan for Death...provides a sound basis for guiding management actions within...management, water resources, biological and...cultural resources, human health and...

2012-06-05

8

Geology of Death Valley National Park  

NSDL National Science Digital Library

This site of the United States Geologic Survey (USGS) and the National Park Service (NPS) highlights the geologic history of Death Valley National Park in Nevada and California. The story begins 1.8 billion years ago with the formation of rocks and continues through uplift, faulting, volcanism, early animals of the area, glaciers, and the making of deserts and dunes. A geologic timescale connects to specific events in the history of Death Valley. There are topographic maps of the area, a field trip of the park, an image gallery, and technical papers available to download.

9

Geology Fieldnotes: Death Valley National Park, California/Nevada  

NSDL National Science Digital Library

This Death Valley National Park site contains park geology information, park maps, photographs, visitor information, and teacher features (resources for teaching geology using National Park examples). The Park Geology section contains an exaggerated cross-section showing the vertical rise within Death Valley. A link is provided to Death Valley's expanded geology page.

10

RisNyt NO2 2005 Broen over Death Valley  

E-print Network

RisøNyt NO2 2005 Broen over Death Valley I november 2004 afsatte Ministeriet for Videnskab bruges til at hjælpe lovende ideer over Death Valley", siger Jeppe Jessen fra Risø Innovations Aktiviteter. "Death Valley" er et internationalt udtryk for den kløft, der opstår mellem den egentlige

11

Space Radar Image of Death Valley, California  

NASA Technical Reports Server (NTRS)

This image shows Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. The goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios. Death Valley is also one of the primary calibration sites for SIR-C/X-SAR. The bright dots near the center of the image are corner reflectors that have been set-up to calibrate the radar as the shuttle passes overhead. Thirty triangular-shaped reflectors (they look like aluminum pyramids) have been deployed by the calibration team from JPL over a 40- by 40-kilometer (25- by 25-mile) area in and around Death Valley. The calibration team will also deploy transponders (electronic reflectors) and receivers to measure the radar signals from SIR-C/X-SAR on the ground. SIR-C/X-SAR is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI).

1999-01-01

12

Transforming the "Valley of Death" into a "Valley of Opportunity"  

NASA Technical Reports Server (NTRS)

Transitioning technology from research to operations (23 R2O) is difficult. The problem's importance is exemplified in the literature and in every failed attempt to do so. Although the R2O gap is often called the "valley of death", a recent a Space Weather editorial called it a "Valley of Opportunity". There are significant opportunities for space weather organizations to learn from the terrestrial experience. Dedicated R2O organizations like those of the various NOAA testbeds and collaborative "proving ground" projects take common approaches to improving terrestrial weather forecasting through the early transition of research capabilities into the operational environment. Here we present experience-proven principles for the establishment and operation of similar space weather organizations, public or private. These principles were developed and currently being demonstrated by NASA at the Applied Meteorology Unit (AMU) and the Short-term Prediction Research and Transition (SPoRT) Center. The AMU was established in 1991 jointly by NASA, the U.S. Air Force (USAF) and the National Weather Service (NWS) to provide tools and techniques for improving weather support to the Space Shuttle Program (Madura et al., 2011). The primary customers were the USAF 45th Weather Squadron (45 WS) and the NWS Spaceflight Meteorology Group (SMG who provided the weather observing and forecast support for Shuttle operations). SPoRT was established in 2002 to transition NASA satellite and remote-sensing technology to the NWS. The continuing success of these organizations suggests the common principles guiding them may be valuable for similar endeavors in the space weather arena.

Jedlovec, Gary J.; Merceret, Francis J.; O'Brien, T. P.; Roeder, William P.; Huddleston, Lisa L.; Bauman, William H., III

2014-01-01

13

3D View of Death Valley, California  

NASA Technical Reports Server (NTRS)

This 3-D perspective view looking north over Death Valley, California, was produced by draping ASTER nighttime thermal infrared data over topographic data from the US Geological Survey. The ASTER data were acquired April 7, 2000 with the multi-spectral thermal infrared channels, and cover an area of 60 by 80 km (37 by 50 miles). Bands 13, 12, and 10 are displayed in red, green and blue respectively. The data have been computer enhanced to exaggerate the color variations that highlight differences in types of surface materials. Salt deposits on the floor of Death Valley appear in shades of yellow, green, purple, and pink, indicating presence of carbonate, sulfate, and chloride minerals. The Panamint Mtns. to the west, and the Black Mtns. to the east, are made up of sedimentary limestones, sandstones, shales, and metamorphic rocks. The bright red areas are dominated by the mineral quartz, such as is found in sandstones; green areas are limestones. In the lower center part of the image is Badwater, the lowest point in North America.

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats, monitoring potentially active volcanoes, identifying crop stress, determining cloud morphology and physical properties, wetlands Evaluation, thermal pollution monitoring, coral reef degradation, surface temperature mapping of soils and geology, and measuring surface heat balance.

2000-01-01

14

36 CFR 7.26 - Death Valley National Monument.  

Code of Federal Regulations, 2014 CFR

...Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR...SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM 7.26 Death Valley...authorized officer or employee of the National Park Service the surface of the...

2014-07-01

15

The Shape of Trail Canyon Alluvial Fan, Death Valley  

NASA Technical Reports Server (NTRS)

A modified conic equation has been fit to high-resolution digital topographic data for Trail Canyon alluvial fan in Death Valley, California. Fits were accomplished for 3 individual fan units of different age.

Farr, Tom G.; Dohrenwend, John C.

1993-01-01

16

Curie Point Depth Estimates from Aeromagnetic Data from Death Valley and Surrounding Regions, California  

NASA Astrophysics Data System (ADS)

Aeromagnetic data were analyzed to determine the Curie point depth (CPD) by power density spectral and three-dimensional inversion methods within and surrounding Death Valley in southern California. We calculated the CPD for 0.5 regions using 2D power density spectral methods and found that the CPDs varied between 8 and 17 km. However, the 0.5 region may average areas that include shallow and deep CPDs, and because of this limitation, we used the 3D inversion method to determine if this method may provide better resolution of the CPDs. The final 3D model indicates that the depth to the bottom of the magnetic susceptible bodies varies between 5 and 23 km. Even though both methods produced roughly similar results, the 3D inversion method produced a higher lateral resolution of the CPDs. The shallowest CPDs occur within the central and southern Death Valley, Panamint Valley, Coso geothermal field and the Tecopa hot springs region. Deeper (>15 km) CPDs occur over outcropping granitic and Precambrian lithologies in the Panamint Range, Grapevine Mountains, Black Mountains and the Argus Range. The shallowest CPD occurs within the central Death Valley over a possible seismically imaged magma body and slightly deeper values occur within the Panamint Valley, southern Death Valley and Tecopa Hot Springs. The shallow CPD values suggest that partially molten material may also be found in these latter regions. The CPD computed heat flow values for the region suggest that the entire area has high heat flow values (>100 mW m-2), on the other hand, locally extremely high values (>200 mW m-2) occur within the Panamint Valley, the southern and central Death Valley and Tecopa Hot Springs region. These locally high heat flow values may be related to midcrustal magma bodies; but additional geophysical experiments are needed to determine if the magma bodies exist.

Hussein, Musa; Mickus, Kevin; Serpa, Laura F.

2013-04-01

17

October 14, 2011 One road out of ,,the Valley of Death  

E-print Network

October 14, 2011 One road out of ,,the Valley of Death Rosibel Ochoa, Geert Schmid-Schonbein & John? You wouldnt if youd ever heard of the "Valley of Death." The Valley of Death represents the funding are developing "proof of concept" centers that help startup companies survive the Valley of Death. One

Russell, Lynn

18

Mapping the translational science policy valley of death  

PubMed Central

Translating the knowledge from biomedical science into clinical applications that help patients has been compared to crossing a valley of death because of the many issues that separate the bench from the bedside and threaten to stall progress. But translation is also inhibited by a science policy environment with its own impediments. Mapping these policy impediments give a more complete picture of the valley of death. Stem cell science is one example where success in moving from the bench to the bedside has confronted policy challenges generating difficulties as challenging as those facing scientists and clinicians. We highlight some of the characteristics and challenges of the science policy valley of death common to the U.S. and Europe, illustrate them with a recent example from stem cell science, and describe some promising strategies for traversing the valley. PMID:23889844

2013-01-01

19

Interseismic deformation and geologic evolution of the Death Valley Fault Zone  

E-print Network

Death Valley Fault Zone (NDVFZ), the Black Mountains Fault Zone (BMFZ) and the Southern Death ValleyInterseismic deformation and geologic evolution of the Death Valley Fault Zone Cecilia Del Pardo,1 Received 31 May 2011; revised 3 April 2012; accepted 20 April 2012; published 8 June 2012. [1] The Death

Blewitt, Geoffrey

20

G-SRT Mt. Whitney to Death Valley  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: The Morris family is on a road trip through California. One day they are driving from Death Valley to Sequoia National Park. Death Valley is home to th...

21

Kinematics at Death Valley-Garlock fault zone junction  

SciTech Connect

The Garlock and Death Valley fault zones in southeast California are two active strike-slip faults that come together on the east side of the Avawatz Mountains. The kinematics of this intersection, and the possible continuation of either fault zone, is being investigated using a combination of detailed field mapping, and processing and interpretation of remotely sensed image data from satellite and aircraft platforms. Regional and local relationships are derivable from the thematic Mapper data (30 m resolution), including discrimination and relative age dating of alluvial fans, bedrock mapping, and fault mapping. Aircraft data provide higher spatial resolution data over more limited areas. Hypotheses that are being considered are (1) the Garlock fault extends east of the intersection; (2) the Garlock fault terminates at the intersection and the Death Valley fault continues southeastward; and (3) the Garlock fault has been offset right laterally by the Death Valley fault that continues to the southeast. Preliminary work indicates that the first hypothesis is invalid. Kinematic considerations, image analysis, and field work results favor the third hypothesis. The projected continuation of the Death Valley zone defines the boundary between the Mojave crustal block and the Basin and Range block.

Abrams, R.B.; Verosub, K.; Finnerty, A.

1987-08-01

22

The Black Mountains turtlebacks: Rosetta stones of Death Valley tectonics  

E-print Network

The Black Mountains turtlebacks: Rosetta stones of Death Valley tectonics Marli B. Miller a, United States Accepted 1 April 2005 Abstract The Black Mountains turtlebacks expose mid-crustal rock along the western front of the Black Mountains. As such, they provide keys to understanding the Tertiary

Miller, Marli Bryant

23

State Partnership for Energy Efficient Demonstrations: Market Transformation Partnerships for Crossing the "Valley of Death"  

E-print Network

for Crossing the "Valley of Death" Karl Johnson, California Institute for Energy and Environment David succumb to the "valley of death," a set of perilous barriers to market introduction that can prevent best

California at Davis, University of

24

Spatial variations in slip rate along the Death Valley-Fish Lake Valley fault system determined from LiDAR topographic data and  

E-print Network

Spatial variations in slip rate along the Death Valley-Fish Lake Valley fault system determined; accepted 11 July 2007; published 19 September 2007. [1] The Death Valley-Fish Lake Valley fault zone (DV determined for the system in northern Death Valley, indicating that slip rates decrease northward along

Frankel, Kurt L.

25

A Case Study: Death Valley National Monument California-Nevada1  

E-print Network

A Case Study: Death Valley National Monument California-Nevada1 Dan Hamson and Toni Ristau 2/ 1 consequences of mining on claims within Death Valley National Monument. In addition, the Secretary's recommendation to Congress. INTRODUCTION Death Valley National Monument was established in February 1933

Standiford, Richard B.

26

A 100 ka record of water tables and paleoclimates from salt cores, Death Valley, California  

Microsoft Academic Search

Sedimentary and petrographic features of evaporites and associated sediments from a 185 m deep core taken in Death Valley, CA, together with uranium-series dating have been used to reconstruct the history of water table fluctuations and climate changes in Death Valley for the past 100 ka. Death Valley has been arid during the Holocene (010 ka), with predominantly mudflat and

Jianren Li; Tim K. Lowenstein; Christopher B. Brown; Teh-Lung Ku; Shangde Luo

1996-01-01

27

Seismic depth imaging of normal faulting in the southern Death Valley Basin  

Microsoft Academic Search

Motivated by the need to image faults to test Cenozoic extension models for the Death Valley region of the western Basin and Range province, an area of strong lateral velocity variations, we examine the geometry of normal faulting in southern Death Valley by seismic depth imaging. We analyze COCORP Death Valley Line 9 to attain an enhanced image of shallow

Sergio Cha?vez-Pe?rez; John N. Louie; Sathish K. Pullammanappallil

1998-01-01

28

Death Valley bright spot: a midcrustal magma body in the southern Great Basin, California  

SciTech Connect

A previously unrecognized midcrustal magma body may have been detected by COCORP deep seismic reflection profiles in the Death Valley region of the southern Great Basin. High-amplitude, relatively broad-band reflections at 6 s (15 km) are attributed to partially molten material within a subhorizontal intrusion. This bright spot extends laterally at least 15 km beneath central Death Valley. A moderately dipping normal fault can be traced from the inferred magma chamber upward to a 690,000-yr-old basaltic cinder cone. The fault zone is inferred to have been a magma conduit during the formation of the cinder cone. Vertical variations in crustal reflection character suggest that the Death Valley magma body may have been emplaced along a zone of decoupling that separates a faulted brittle upper crust from a more ductile and/or intruded lower crust. The Death Valley bright spot is similar to reflections recorded by COCORP in 1977 in the Rio Grande rift, where both geophysical and geodetic evidence support the inference of a tabular magma chamber at 20-km depth.

de Voogd, B.; Serpa, L.; Brown, L.; Hauser, E.; Kaufman, S.; Oliver, J.; Troxel, B.W.; Willemin, J.; Wright, L.A.

1986-01-01

29

Hydrology of modern and late Holocene lakes, Death Valley, California  

SciTech Connect

Above-normal precipitation and surface-water runoff, which have been generally related to the cyclic recurrence of the El Nino-Southern Oscillation, have produced modern ephemeral lakes in the closed-basin Death Valley watershed. This study evaluates the regional hydroclimatic relations between precipitation, runoff, and lake transgressions in the Death Valley watershed. Recorded precipitation, runoff, and spring discharge data for the region are used in conjunction with a closed-basin, lake-water-budget equation to assess the relative contributions of water from these sources to modern lakes in Death Valley and to identify the requisite hydroclimatic changes for a late Holocene perennial lake in the valley. As part of the Yucca Mountain Site Characterization Program, an evaluation of the Quaternary regional paleoflood hydrology of the potential nuclear-waste repository site at Yucca Mountain, Nevada, was planned. The objectives of the evaluation were (1) to identify the locations and investigate the hydraulic characteristics of paleofloods and compare these with the locations and characteristics of modern floods, and (2) to evaluate the character and severity of past floods and debris flows to ascertain the potential future hazards to the potential repository during the pre-closure period (US Department of Energy, 1988). This study addresses the first of these objectives, and the second in part, by assessing and comparing the sizes, locations, and recurrence rates of modern, recorded (1962--83) floods and late Holocene paleofloods for the 8,533-mi{sup 2}, closed-basin, Death Valley watershed with its contributing drainage basins in the Yucca Mountain site area.

Grasso, D.N.

1996-07-01

30

Microscopic identification of prokaryotes in modern and ancient halite, Saline Valley and Death Valley, California.  

PubMed

Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 microm diameter cocci, <2.5 microm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System. PMID:19566426

Schubert, Brian A; Lowenstein, Tim K; Timofeeff, Michael N

2009-06-01

31

Recent landscape change in California's Central Valley  

NASA Astrophysics Data System (ADS)

Long term monitoring of land use and land cover in California's intensively farmed Central Valley reveals several key physical and socioeconomic factors driving landscape change. As part of the USGS Land Cover Trends Project, we analyzed modern land-use/land-cover change for the California Central Valley ecoregion between 2000 and 2010, monitoring annual change between 2005 and 2010, while creating two new change intervals (2000-2005 and 2005-2010) to update the existing 27-year, interval-based analysis. Between 2000 and 2010, agricultural lands fluctuated due to changes in water allocations and emerging drought conditions, or were lost permanently to development (240 square km). Land-use pressure from agriculture and development also led to a decline in grasslands and shrublands across the region (280 square km). Overall, 400 square km of new developed lands were added in the first decade of the 21st century. From 2007 to 2010, development only expanded by 50 square km, coinciding with defaults in the banking system, the onset of historic foreclosure crisis in California and the global economic downturn. Our annual LULC change estimates capture landscape-level change in response to regional policy changes, climate, and fluctuations (e.g., growth or decline) in the national and global economy. The resulting change data provide insights into the drivers of landscape change in the California Central Valley and the combination of two consistent mapping efforts represents the first continuous, 37-year endeavor of its kind.

Soulard, C. E.; Wilson, T. S.

2012-12-01

32

Ground Watering of the Death Valley Region, Nevada and California  

SciTech Connect

Water is a precious commodity, especially in the arid southwest region of the US, where there is a limited supply of both surface water and ground water. Ground water has a variety of uses (such as agricultural, commercial, and domestic) in the Death Valley regional ground-water flow system (DVRFS) of southern Nevada and eastern California. The DVRFS, an area of about 100,000 square kilometers, contains very complex geology and hydrology. Using a computer model to represent this complex system the US Geological Survey (USGS) simulated ground-water flow in the Death Valley region for use with US Department of Energy (DOE) projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the Nation's proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada.

USGS

2006-10-12

33

Sedimentary facies of alluvial fan deposits, Death Valley, California  

SciTech Connect

Fans in Death Valley include both diamicts and bedded gravels. Seven facies may be recognized. The diamicts include: (1) matrix-rich, coarse wackestones; (2) thin, matrix-rich, fine wackestones, that may show grading; (3) matrix-poor, coarse packstones, transitional to wackestones. The bedded facies include: (4) weakly bedded, poorly sorted packstones or grainstones, that show patchy imbrication, and cut-and-fill structures; (5) packed, imbricated cobble lenses, generally interbedded in facies 4; (6) distinctly bedded gravels, that are better bedded, finer and better sorted, and show better imbrication than facies 4, but still do not show clear separation of sand and gravel beds; (7) backfill cross-bedded gravels. Sand beds are not seen in fan deposits. Sand is present in eolian deposits, as plane-laminated, back-eddy deposits in Death Valley Wash, and as laminated or rippled sand in the Amargosa River. The most remarkable features of the fan deposits are the very weak segregation of sand and gravel, and the complete absence of any lower flow-regime structures produced by ripples or dunes. During floods, the slope of fan and even large wash surfaces is steep enough to produce upper flow regimes. There are also very few trends in facies abundance down fans: most fans in Death Valley itself are not strongly dominated by debris flow deposits (diamicts). The facies characteristics of a given fan vary little from proximal to distal regions, but may differ strongly from the facies seen in adjacent fans. Ancient deposits that show clear segregation of gravel from cross-bedded sand beds, or strong proximal to distal facies transitions, must have been deposited in environments quite different from Death Valley.

Middleton, G.V. (McMaster Univ., Hamilton, Ontario (Canada))

1992-01-01

34

Discrimination of geologic units in Death Valley using dual frequency and polarization imaging radar data  

NASA Technical Reports Server (NTRS)

A simultaneous analysis of dual-frequency and dual-polarization radar imagery of an area located in the central part of Death Valley, Calif., is discussed. The radar imagery analyzed consists of like-polarized L-band, cross-polarized L-band, and like-polarized X-band imagery digitally combined and ratioed to enhance the variation in the backscatter cross section of different geologic units. It is shown that simultaneous analysis of such radar imagery leads to a synergism effect which, in the case of the area studied in Death Valley, allows nearly complete discrimination of surficial geologic units. Radar backscatter is found generally to increase with roughness from smooth Quaternary sand facies to rough and extremely rough Quaternary silty rock salt.

Daily, M.; Elachi, C.; Farr, T.

1978-01-01

35

Imaging Radar Applications in the Death Valley Region  

NASA Technical Reports Server (NTRS)

Death Valley has had a long history as a testbed for remote sensing techniques (Gillespie, this conference). Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the valley since the 1970's, yielding new insights into the geologic applications of that technology. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in Death Valley because it has a variety of surface types in a small area without the confounding effects of vegetation. In one of the classic references of these early radar studies, in a semi-quantitative way the response of an imaging radar to surface roughness near the radar wavelength, which typically ranges from about 1 cm to 1 m was explained. This laid the groundwork for applications of airborne and spaceborne radars to geologic problems in and regions. Radar's main advantages over other sensors stems from its active nature- supplying its own illumination makes it independent of solar illumination and it can also control the imaging geometry more accurately. Finally, its long wavelength allows it to peer through clouds, eliminating some of the problems of optical sensors, especially in perennially cloudy and polar areas.

Farr, Tom G.

1996-01-01

36

Into the valley of death: research to innovation.  

PubMed

The phase between research and successful innovation is known as the valley of death. Increasingly, researchers from the pharmaceutical industry and academia are working together, often encouraged by governments, to cross this 'valley' as they seek to bring basic research to the market. This is consistent with newer models of innovation policy that stress interaction between the different agents across the innovation process. Here, we examine this interaction in the UK, the EU and the USA using several specific examples, suggesting that cooperation is still far from perfect and that the return for academia on its research investment is relatively small. Countries are also beginning to use research as a tool of industrial economic policy. PMID:23402848

Hudson, John; Khazragui, Hanan F

2013-07-01

37

Imaging Radar in the Mojave Desert-Death Valley Region  

NASA Technical Reports Server (NTRS)

The Mojave Desert-Death Valley region has had a long history as a test bed for remote sensing techniques. Along with visible-near infrared and thermal IR sensors, imaging radars have flown and orbited over the area since the 1970's, yielding new insights into the geologic applications of these technologies. More recently, radar interferometry has been used to derive digital topographic maps of the area, supplementing the USGS 7.5' digital quadrangles currently available for nearly the entire area. As for their shorter-wavelength brethren, imaging radars were tested early in their civilian history in the Mojave Desert-Death Valley region because it contains a variety of surface types in a small area without the confounding effects of vegetation. The earliest imaging radars to be flown over the region included military tests of short-wavelength (3 cm) X-band sensors. Later, the Jet Propulsion Laboratory began its development of imaging radars with an airborne sensor, followed by the Seasat orbital radar in 1978. These systems were L-band (25 cm). Following Seasat, JPL embarked upon a series of Space Shuttle Imaging Radars: SIRA (1981), SIR-B (1984), and SIR-C (1994). The most recent in the series was the most capable radar sensor flown in space and acquired large numbers of data swaths in a variety of test areas around the world. The Mojave Desert-Death Valley region was one of those test areas, and was covered very well with 3 wavelengths, multiple polarizations, and at multiple angles. At the same time, the JPL aircraft radar program continued improving and collecting data over the Mojave Desert Death Valley region. Now called AIRSAR, the system includes 3 bands (P-band, 67 cm; L-band, 25 cm; C-band, 5 cm). Each band can collect all possible polarizations in a mode called polarimetry. In addition, AIRSAR can be operated in the TOPSAR mode wherein 2 antennas collect data interferometrically, yielding a digital elevation model (DEM). Both L-band and C-band can be operated in this way, with horizontal resolution of about 5 m and vertical errors less than 2 m. The findings and developments of these earlier investigations are discussed.

Farr, Tom G.

2001-01-01

38

U-Series Chronology of Lacustrine Deposits in Death Valley, California  

Microsoft Academic Search

Uranium-series dating on a 186-m core (DV93-1) drilled from Badwater Basin in Death Valley, California, and on calcareous tufas from nearby strandlines shows that Lake Manly, the lake that periodically flooded Death Valley during the late Pleistocene, experienced large fluctuations in depth and chemistry over the last 200,000 yr. Death Valley has been occupied by a long-standing deep lake, perennial

Teh-Lung Ku; Shangde Luo; Tim K. Lowenstein; Jianren Li; Ronald J. Spencer

1998-01-01

39

Paleoseismology of the Southern Section of the Black Mountains and Southern Death Valley Fault Zones, Death Valley, United States  

USGS Publications Warehouse

The Death Valley Fault System (DVFS) is part of the southern Walker Laneeastern California shear zone. The normal Black Mountains Fault Zone (BMFZ) and the right-lateral Southern Death Valley Fault Zone (SDVFZ) are two components of the DVFS. Estimates of late Pleistocene-Holocene slip rates and recurrence intervals for these two fault zones are uncertain owing to poor relative age control. The BMFZ southernmost section (Section 1W) steps basinward and preserves multiple scarps in the Quaternary alluvial fans. We present optically stimulated luminescence (OSL) dates ranging from 27 to 4 ka of fluvial and eolian sand lenses interbedded with alluvial-fan deposits offset by the BMFZ. By cross-cutting relations, we infer that there were three separate ground-rupturing earthquakes on BMFZ Section 1W with vertical displacement between 5.5 m and 2.75 m. The slip-rate estimate is ?0.2 to 1.8 mm/yr, with an earthquake recurrence interval of 4,500 to 2,000 years. Slip-per-event measurements indicate Mw 7.0 to 7.2 earthquakes. The 274-ka OSL-dated alluvial fans also overlie the putative Cinder Hill tephra layer. Cinder Hill is offset ?213 m by SDVFZ, which yields a tentative slip rate of 1 to 8 mm/yr for the SDVFZ.

Sohn, Marsha S.; Knott, Jeffrey R.; Mahan, Shannon A.

2014-01-01

40

Color Image of Death Valley, California from SIR-C  

NASA Technical Reports Server (NTRS)

This radar image shows the area of Death Valley, California and the different surface types in the area. Radar is sensitive to surface roughness with rough areas showing up brighter than smooth areas, which appear dark. This is seen in the contrast between the bright mountains that surround the dark, smooth basins and valleys of Death Valley. The image shows Furnace Creek alluvial fan (green crescent feature) at the far right, and the sand dunes near Stove Pipe Wells at the center. Alluvial fans are gravel deposits that wash down from the mountains over time. Several other alluvial fans (semicircular features) can be seen along the mountain fronts in this image. The dark wrench-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using these radar data to help answer a number of different questions about Earth's geology including how alluvial fans form and change through time in response to climatic changes and earthquakes. The image is centered at 36.629 degrees north latitude, 117.069 degrees west longitude. Colors in the image represent different radar channels as follows: red =L-band horizontally polarized transmitted, horizontally polarized received (LHH); green =L-band horizontally transmitted, vertically received (LHV) and blue = CHV.

SIR-C/X-SAR is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI).

1999-01-01

41

Variation and Divergence of Death Valley Pupfish Populations at Retrotransposon-Defined Loci  

Microsoft Academic Search

A population survey of the Death Valley pupfishes (Cyprinodontidae: Cyprinodon sp.) for insertional variation associated with ''Swimmer 1'' (SW1), a retrotransposon family, was conducted with Southern blot hybridization. Numerous polymorphic insertion sites were detected, providing compelling evidence that SW1 has been retrotrans- positionally active in the recent history of the Death Valley pupfishes. This extensive variation revealed marked genetic divergence

David D. Duvernell; Bruce J. Turner

42

Factors influencing species diversity in saline waters of Death Valley, USA  

Microsoft Academic Search

Salinity is a major factor influencing the distributions and abundances of aquatic macroinvertebrates of saline waters in Death Valley, California, USA. A general pattern of declining numbers of species with increasing salinity is seen in Death Valley waters. Some species are restricted to low salinities, others are found only in highly saline pools, and still others are widely distributed over

Elizabeth A. Colburn

1988-01-01

43

Surface roughness, radar backscatter, and visible and near-infrared reflectance in Death Valley, California  

Microsoft Academic Search

The vast alluvial fans of Death Valley, California, provide an ideal environment to examine the remote sensing measurement of geologic surfaces. One of the objectives of the shuttle imaging radar C (SIR C) program in Death Valley is detection of the variation in surface microtopography with age of the surface. We present results of extensive field measurements of surface roughness

Milton Smith; Kyung Pak; Wen-Hao Li; Alan Gillespie; Bill Gustafson

1996-01-01

44

Expert elicitation of recharge model probabilities for the Death Valley regional flow system  

Microsoft Academic Search

Summary This study uses expert elicitation to evaluate and select five alternative recharge models developed for the Death Valley regional flow system (DVRFS), covering southeast Nevada and the Death Valley area of California, USA. The five models were developed based on three independent techniques: an empirical approach, an approach based on unsaturated-zone studies and an approach based on saturated-zone studies.

Ming Ye; Karl F. Pohlmann; Jenny B. Chapman

2008-01-01

45

In the Death Valley region of the Mojave Desert, the Neoproterozoic-Cambrian boundary  

E-print Network

ABSTRACT In the Death Valley region of the Mojave Desert, the Neoproterozoic-Cambrian boundary lies States. In the Death Valley region of the southwestern Mojave Desert, the Neoproterozoic. Locality map. Inset map shows state of Nevada, with Nye County indicated in black. #12;Stirling Quartzite

Hagadorn, Whitey

46

Space Radar Image of Death Valley in 3-D  

NASA Technical Reports Server (NTRS)

This picture is a three-dimensional perspective view of Death Valley, California. This view was constructed by overlaying a SIR-C radar image on a U.S. Geological Survey digital elevation map. The SIR-C image is centered at 36.629 degrees north latitude and 117.069 degrees west longitude. We are looking at Stove Pipe Wells, which is the bright rectangle located in the center of the picture frame. Our vantage point is located atop a large alluvial fan centered at the mouth of Cottonwood Canyon. In the foreground on the left, we can see the sand dunes near Stove Pipe Wells. In the background on the left, the Valley floor gradually falls in elevation toward Badwater, the lowest spot in the United States. In the background on the right we can see Tucki Mountain. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the Valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help the answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. The goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios. Vertical exaggeration is 1.87 times; exaggeration of relief is a common tool scientists use to detect relationships between structure (for example, faults and fractures) and topography. Death Valley is also one of the primary calibration sites for SIR-C/X-SAR. In the lower right quadrant of the picture frame two bright dots can be seen which form a line extending to Stove Pipe Wells. These dots are corner reflectors that have been set up to calibrate the radar as the shuttle passes overhead. Thirty triangular-shaped reflectors (they look like aluminum pyramids) have been deployed by the calibration team from JPL over a 40- by 40-kilometer (25- by 25-mile) area in and around Death Valley. The signatures of these reflectors were analyzed by JPL scientists to calibrate the image used in this picture. The calibration team here also deployed transponders (electronic reflectors) and receivers to measure the radar signals from SIR-C/X-SAR on the ground. SIR-C/X-SAR radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, in conjunction with aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche

1999-01-01

47

California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley  

USGS Publications Warehouse

Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

2009-01-01

48

ANALYSIS OF LOTIC MACROINVERTEBRATE ASSEMBLAGES IN CALIFORNIA'S CENTRAL VALLEY  

EPA Science Inventory

Using multivariate and cluster analyses, we examined the relaitonships between chemical and physical characteristics and macroinvertebrate assemblages at sites sampled by R-EMAP in California's Central Valley. By contrasting results where community structure was summarized as met...

49

Wellcome Trust SUBMISSION OF EVIDENCE Wellcome Trust response to Bridging the "valley of death": improving the commercialisation of research  

E-print Network

Wellcome Trust SUBMISSION OF EVIDENCE Wellcome Trust response to Bridging the "valley of death Committee: Bridging the "valley of death": improving the commercialisation of research Response by the Wellcome Trust February 2012 Key Points The valley of death is not merely a funding gap. While funding

Rambaut, Andrew

50

Do phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than present hydro-climate?  

E-print Network

Do phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than. The predominance of this type of activity at the Ubehebe volcanic field in northern Death Valley, California phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than present hydro

Christie-Blick, Nicholas

51

Preliminary Assessment of Urban Growth in California's Central Valley  

NSDL National Science Digital Library

This preliminary assessment of urban growth in the Central Valley of California is intended to illustrate the dramatic changes to the Central Valley landscape over the past 100 years. Data products include an urban growth timeline for the years 1900 to 1996, an animated version of the same timeline, and graphs showing the increase in population and built-up land for the same period.

52

Comment on Testing the Interbasin Flow Hypothesis at Death Valley, California  

NASA Astrophysics Data System (ADS)

In the 1960s, a major hydrogeologic investigation was conducted at the Nevada Test Site (NTS, Figure 1) that included drilling, hydraulic testing, and hydrogeochemical studies in conjunction with geologic mapping and geophysical surveys. This work demonstrated that a large part of south central Nevada is underlain by thick (several kilometers) highly fractured Paleozoic carbonate rocks that typically act as an aquifer. The aquifer flanks and underlies most of the intermontane basins from east central Nevada southward, through the NTS, to the southern Funeral Mountains east of Death Valley (Figure 1). Water levels measured in many test holes demonstrate that the potentiometric surface in the carbonate aquifer generally is uninterrupted by the ridges that separate the many topographically closed basins of the region.

Winograd, Isaac J.; Fridrich, Christopher J.; Sweetkind, Donald; Belcher, Wayne R.; Thomas, James M.

53

Rapid uplift and crustal growth in extensional environments: An isotopic study from the Death Valley region, California  

Microsoft Academic Search

The Willow Spring Diorite, in the Black Mountains of the central Death Valley extended terrain, yields a U-Pb zircon age of 11.6 {plus minus} 0.2 Ma. ⁴°Ar-³⁹Ar analyses of hornblende and U-Pb analyses of sphene from this sample give ages of about 10 Ma, indicating that the batholith remained above about 500 C for about 1.5 m.y. after crystallization. Geologic

Yemane Asmerom; J. Kent Snow; Daniel K. Holm; Stein B. Jacobsen; Brian P. Wernicke; Daniel R. Lux

1990-01-01

54

Quaternary tilt of Death Valley determined from landform modelling of alluvial fans  

SciTech Connect

Alluvial fans along the east side of central Death Valley are being actively back-tilted along the Death Valley fault zone. Initial modelling of the Copper Canyon and Furnace Creek fans led to recognition of distinct segments. Field reconnaissance and aerial photo mapping were conducted to check model results and improve segment discrimination. Surface roughness, relative position, vegetation distribution, and drainage patterns provided independent evidence for segment discrimination. Subsequent modelling of individual segments produced a range of tilt values from 0.275[degree] to 0.559[degree] down to the northeast. Continued analysis of these fan segments is concentrated on: (1) assigning confidence and error values to the tilt values; and (2) dating individual segments. Further work will compare the tilt rates of east-side fans with those from the west. The mean squared error (MSE) is currently being used as a first order assessment of the quality of the model's fit to data digitized from 1:24,000 scale USGS topographic maps. MSE values of 1 m or less can be expected for relatively young or actively aggrading segments. Previous fan models have found the expected range of misfits to be between 2 m and 5 m. This seven parameter least squares model has produced fits with less than 2 m total range in misfits. Previous models have not accounted for tilt or have relied on simplifying assumptions to fix apex position.

West, R.B.; Wilson, D.S. (Univ. of California, Santa Barbara, CA (United States). Dept. of Geology)

1993-04-01

55

Interpretation and tectonic implications of cooling histories: An example from the Black Mountains, Death Valley, CA  

SciTech Connect

Cooling histories of footwall rocks in extensional terranes provide one method for constraining the timing, amount, and nature of unroofing. New fission-track ages from the black Mountains of Death Valley, California are combined with published Ar-40/Ar-39 ages to construct cooling-path envelopes for a transect across the range. The cooling history reconstructions are used to differentiate between contrasting unroofing histories proposed for this range. The data are projected onto a 45 km northwest-oriented section from the basal nonconformity in the southeast part of the range to the Death Valley antiforms (turtlebacks). Mineral ages decrease and converge with one another toward the northwest, with increasing distance from the nonconformity. Old cooling-ages from basement just beneath the Amargosa chaos (in the middle of the section) are consistent with the chaos rocks ( and immediate underlying basement) being part of an allochtonous, northwest-transported, hanging wall slice. The monotonically decreasing cooling ages across the central core of the range are consistent with cooling along a single gently northwest dipping detachment zone. Models proposed unroofing along a series of high-angle normal faults throughout the range are difficult to reconcile with this pattern of cooling.

Holm, D. (Kent State Univ., OH (United States). Dept. of Geology); Dokka, R. (NSF, Washington, DC (United States). Div. of Earth Sciences)

1992-01-01

56

Halophilic Archaea cultured from ancient halite, Death Valley, California.  

PubMed

Halophilic Archaea cultured from ancient fluid inclusions in a 90-m-long (0- to 100,000-year-old) salt core from Death Valley, California, demonstrate survival of bacterial cells in subsurface halite for up to 34,000 years. Five enrichment cultures, representing three genera of halophilic Archaea (Halorubrum, Natronomonas and Haloterrigena), were obtained from five surface-sterilized halite crystals exclusively in one section of the core (13.0-17.8 m; 22,000-34,000 years old) containing perennial saline lake deposits. Prokaryote cells were observed microscopically in situ within fluid inclusions from every layer that produced culturable cells. Another 876 crystals analysed from depths of 8.1-86.7 m (10,000-100,000 years old) failed to yield live halophilic Archaea. Considering the number of halite crystals tested (culturing success of 0.6%), microbial survival in fluid inclusions in halite is rare and related to the paleoenvironment, which controls the distribution and abundance of trapped microorganisms. Two cultures from two crystals at 17.8 m that yielded identical 16S rRNA sequences (genus: Haloterrigena) demonstrate intra-laboratory reproducibility. Inter-laboratory reproducibility is shown by two halophilic Archaea (genus: Natronomonas), with 99.3% similarity of 16S rRNA sequences, cultured from the same core interval, but at separate laboratories. PMID:19840101

Schubert, Brian A; Lowenstein, Tim K; Timofeeff, Michael N; Parker, Matthew A

2010-02-01

57

National Uranium Resource Evaluation: Death Valley Quadrangle, California and Nevada  

SciTech Connect

The Death Valley quadrangle, California and Nevada, was evaluated for geologic environments favorable for uranium deposits in accordance with criteria developed for the National Uranium Resource Evaluation program. Reconnaissance radiometric and geochemical surveys were conducted in all geologic environments open to evaluation. Detailed surface and subsurface investigations were conducted in potential host and source environments. Subsurface data collected by private industry were obtained for all favorable environments. The results of this investigation indicate environments favorable for fluviolacustrine deposits in the Coso Formation of Tertiary age; metamorphosed lagoonal deposits in the Limekiln Spring member of the Kingston Peak Formation of late Precambrian age; and hydroallogenic and pneumatogenic deposits in Miocene rhyolites related to the Bullfrog Hills caldera. Environments in the quadrangle considered unfavorable for uranium deposits are plutonic rocks of Mesozoic age; sedimentary rocks of Precambrian, Paleozoic, Mesozoic, and Tertiary ages (other than those of the Coso Formation); volcanic rocks of Tertiary age (other than those of the Bullfrog caldera); and metamorphic rocks of Precambrian and Mesozoic ages (other than those of the Kingston Peak Formation). Substantial portions of the quadrangle remain unevaluated because of restricted access or lack of sufficient subsurface data.

Berridge, W.C.

1982-09-01

58

Outcrop Geology of Plio-Pleistocene Strata of the Confidence Hills, Southern Death Valley,  

E-print Network

, Southern Death Valley, California, are composed of Plio-Pleistocene lacustrine beds, evaporite beds, ashes outcrop map illustrating these subdivisions is included. Companion papers (Pluhar et al. and Beratan

59

Morphological and Geomicrobiological Characteristics of an Endolithic Microbial Community from the Badwater Basin, Death Valley, California  

NASA Technical Reports Server (NTRS)

ESEM-EDS studies of an endolithic evaporite community from Death Valley revealed its ability to sequester water and affect the partitioning of trace metals in this environment. Additional information is contained in the original extended abstract.

Douglas, S.

2001-01-01

60

Evolution of extensional basins and basin and range topography west of Death Valley, California  

E-print Network

Neogene extension in the Death Valley region, SE California, has produced a variety of sedimentary basins. Diachronous movements on an array of strike-slip and normal fault systems have resulted in the uplift and preservation of older basins...

Hodges, K. V.; McKenna, L. W.; Stock, J.; Knapp, J.; Page, L.; Sternlof, K.; Silverberg, D.; Wust, G.; Walker, J. Douglas

1989-06-01

61

Geologic Map of the Death Valley Ground-water Model Area, Nevada and California  

SciTech Connect

The purpose of this map is to provide the surface expression of the geology in the Death Valley ground-water model area to be incorporated initially into a 3-D geologic framework model and eventually into a transient ground-water flow model by the U.S. Geological Survey (D'Agnese, 2000; D'Agnese and Faunt, 1999; Faunt and others, 1999; and O'Brien and others, 1999). This work has been conducted in collaboration with the U.S. Department of Energy in order to assess regional ground water flow near the Nevada Test Site (NTS) and the potential radioactive waste repository at Yucca Mountain. The map is centered on the NTS and its perimeter encircles the entire boundary of the numerical flow model area, covering a total area of 57,000 km2. The physiography, geology, and tectonics of the model area are extremely complex (Hunt and Mabey, 1966; Stewart, 1980; Jennings, 1994; Slate and others, 2000; Wright and others, 1999b). The northern and eastern part of the area includes typical Basin and Range topography consisting of north-trending block-faulted ranges and intervening valleys. The central part contains diverse ranges, plateaus, basins, and alluvial flats (for example, the NTS volcanic highlands and Amargosa Valley). The rugged ranges and deep basins of the Death Valley region in eastern California are characteristic of the topography of the southern and western parts of the map area. The map spans numerous tectonic subdivisions of the Great Basin. Deformation includes several generations of upper Paleozoic to Mesozoic thrust faulting that have been dismembered by extensive regional Tertiary to Quaternary normal and strike-slip faults. Much of this extensional and translational deformation is active today, with rates and amounts that vary from low to moderate in the central, eastern, and northern parts of the study area in southern Nevada, to very high in the southwestern and western parts in eastern California. For detailed discussion of the tectonic framework of the map area, the reader is referred to Workman and others (2002).

J.B. Workman; C.M. Menges; W.R. Page; E.M. Taylor; E.B. Ekren; P.D. Rowley; G.L. Dixon; R.A. Thompson; L.A. Wright

2003-04-21

62

75 FR 39934 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian...

2010-07-13

63

75 FR 51058 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields...Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian...

2010-08-18

64

The Decline of Amphibians in California's Great Central Valley  

Microsoft Academic Search

Declines in amphibian populations are rarely reported on the community or ecosystem level. We combined broad-scale field sampling with historical analyses of museum records to quantify amphibian de- clines in California's Great Central Valley. Overall, amphibians showed an unambiguous pattern of decline, although the intensity of decline varied both geographically and taxonomically. The greatest geographical de- cline was detected in

Robert N. Fisher; H. Bradley Shaffer

1996-01-01

65

75 FR 15453 - Central Valley Project Improvement Act, Westlands Water District Drainage Repayment Contract  

Federal Register 2010, 2011, 2012, 2013, 2014

...OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act, Westlands Water District Drainage...service to the District located within the San Luis Unit of the Central Valley Project in California. FOR FURTHER INFORMATION...

2010-03-29

66

76 FR 58840 - Central Valley Project Improvement Act; Refuge Water Management Plans  

Federal Register 2010, 2011, 2012, 2013, 2014

...Reclamation Central Valley Project Improvement Act; Refuge Water Management Plans AGENCY: Bureau of...requirements of the Central Valley Project Improvement Act of 1992...for Developing Refuge Water Management Plans (Refuge...

2011-09-22

67

Geologic map of the southern Funeral Mountains including nearby groundwater discharge sites in Death Valley National Park, California and Nevada  

USGS Publications Warehouse

This 1:50,000-scale geologic map covers the southern part of the Funeral Mountains, and adjoining parts of four structural basinsFurnace Creek, Amargosa Valley, Opera House, and central Death Valleyin California and Nevada. It extends over three full 7.5-minute quadrangles, and parts of eleven othersan area of about 1,000 square kilometers (km2). The boundaries of this map were drawn to include all of the known proximal hydrogeologic features that may affect the flow of groundwater that discharges from springs of the Furnace Creek basin, in the west-central part of the map. These springs provide the main potable water supply for Death Valley National Park. Major hydrogeologic features shown on this map include: (1) springs of the Furnace Creek basin, (2) a large Pleistocene groundwater discharge mound in the northeastern part of the map, (3) the exposed extent of limestones and dolomites that constitute the Paleozoic carbonate aquifer, and (4) the exposed extent of the alluvial conglomerates that constitute the Funeral Formation aquifer.

Fridrich, C.J.; Thompson, R.A.; Slate, J.L.; Berry, M.E.; Machette, M.N.

2012-01-01

68

Late quaternary faulting along the Death Valley-Furnace Creek fault system, California and Nevada  

SciTech Connect

The Death Valley-Furnace Creek fault system, in California and Nevada, has a variety of impressive late Quaternary neotectonic features that record a long history of recurrent earthquake-induced faulting. Although no neotectonic features of unequivocal historical age are known, paleoseismic features from multiple late Quaternary events of surface faulting are well developed throughout the length of the system. Comparison of scarp heights to amount of horizontal offset of stream channels and the relationships of both scarps and channels to the ages of different geomorphic surfaces demonstrate that Quaternary faulting along the northwest-trending Furnace Creek fault zone is predominantly right lateral, whereas that along the north-trending Death Valley fault zone is predominantly normal. These observations are compatible with tectonic models of Death Valley as a northwest- trending pull-apart basin.

Brogan, G.E.; Kellogg, K.S.; Terhune, C.L. [Geological Survey, Denver, CO (United States); Slemmons, D.B. [Nevada Univ., Reno, NV (United States). Center for Neotectonic Studies

1991-12-31

69

A neotectonic tour of the Death Valley fault zone, Inyo County  

SciTech Connect

The Death Valley fault zone has recently been evaluated by the Division of Mines and Geology for zoning under the Alquist-Priolo Special Studies Zones Act of 1972. This act requires the State Geologist to zone for special studies those faults that are sufficiently active and well defined as to constitute a potential hazard to structures from surface faulting or fault creep. The Death Valley fault zone is part of a system of faults that extends over 180 miles (300 km) from Fish Lake Valley in Nevada to the Garlock fault. The northern part of this system, the Northern Death Valley-Furnace Creek fault zone, is an active right-lateral fault zone. The southern part of the system, the Death Valley fault zone, is a right-lateral oblique-slip fault between Furnace Creek and Shoreline Butte. From Shoreline Butte to the Garlock fault, it is a right-lateral strike-slip fault. Landforms along this fault indicate that it is the source of many earthquakes and that it has been active in Holocene time. The heights of the scarps and magnitude of the smallest right-lateral offsets (4 feet; 1.2 m) suggest that the most recent of these events was M 6.5 or larger. The freshness of the geomorphic features and the youth of the offset materials suggest that event occurred late in the Holocene, and that multiple Holocene earthquakes have occurred.

Wills, C.J.

1989-09-01

70

Mapping playa evaporite minerals with AVIRIS data - A first report from Death Valley, California  

NASA Technical Reports Server (NTRS)

The feasibility of using imaging spectrometry in studies of playa evaporites is demonstrated by mapping efflorescent salt crusts in Death Valley (California), using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. It is shown that it was possible to remotely identify eight different saline minerals, including three borates that have not been previously reported for the Death Valley efflorescent crusts: hydroboracite, pinnoite, and rivadavite. The three borates are locally important phases in the crusts; at least one of them, rivadavite, appears to be forming directly from brine.

Crowley, James K.

1993-01-01

71

Application of multispectral radar and LANDSAT imagery to geologic mapping in death valley  

NASA Technical Reports Server (NTRS)

Side-Looking Airborne Radar (SLAR) images, acquired by JPL and Strategic Air Command Systems, and visible and near-infrared LANDSAT imagery were applied to studies of the Quaternary alluvial and evaporite deposits in Death Valley, California. Unprocessed radar imagery revealed considerable variation in microwave backscatter, generally correlated with surface roughness. For Death Valley, LANDSAT imagery is of limited value in discriminating the Quaternary units except for alluvial units distinguishable by presence or absence of desert varnish or evaporite units whose extremely rough surfaces are strongly shadowed. In contrast, radar returns are most strongly dependent on surface roughness, a property more strongly correlated with surficial geology than is surface chemistry.

Daily, M.; Elachi, C.; Farr, T.; Stromberg, W.; Williams, S.; Schaber, G.

1978-01-01

72

Was There a Pliocene-Pleistocene Fluvial-Lacustrine Connection between Death Valley and the Colorado River?  

Microsoft Academic Search

Since the turn of the century, a Pliocene-Pleistocene connection between the Death Valley-Owens River pluvial system and the Colorado River drainage basin has been frequently postulated. The two most commonly proposed routes involve (1) a southward overflow from the Death Valley Lake system or (2) southward migration of the Mojave River between its present course and a more southerly route.

William J. Brown; Michael R. Rosen

1995-01-01

73

Comparison of inversion models using AIRSAR data for Death Valley, California  

NASA Technical Reports Server (NTRS)

Polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data were collected for the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley, California, USA, in September 1989. AIRSAR is a four-look, quid-polarizaiton, three frequency instrument. It collects measurements at C-band (5.66 cm), L-band (23.98 cm), and P-band (68.13 cm), and has a GIFOV of 10 meters and a swath width of 12 kilometers. Because the radar measures at three wavelengths, different scales of surface roughness are measured. Also, dielectric constants can be calculated from the data. The scene used in this study is in Death Valley, California and is located over Trail Canyon alluvial fan, the valley floor, and Artists Drive alluvial fan. The fans are very different in mineralogic makeup, size, and surface roughness. Trail Canyon fan is located on the west side of the valley at the base of the Panamint Range and is a large fan with older areas of desert pavement and younger active channels. The source for the material on southern part of the fan is mostly quartzites and there is an area of carbonate source on the northern part of the fan. Artists Drive fan is located at the base of the Black Mountains on the east side of the valley and is a smaller, young fan with its source mostly from volcanic rocks. The valley floor contains playa and salt deposits that range from smooth to Devil's Golf course type salt pinnacles.

Kierein-Young, Kathryn S.

1993-01-01

74

Isostatic gravity map of the Death Valley ground-water model area, Nevada and California  

USGS Publications Warehouse

An isostatic gravity map of the Death Valley groundwater model area was prepared from over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California.

Ponce, D.A.; Blakely, R.J.; Morin, R.L.; Mankinen, E.A.

2001-01-01

75

Mapping playa evaporite minerals and associated sediments in Death Valley, California, with multispectral thermal infrared images  

Microsoft Academic Search

Effiorescent salt crusts and associated sediments in Death Valley, California, were studied with remote-sensing data acquired by the NASA thermal infrared multispectral scanner (TIMS). Nine spectral classes that represent a variety of surface materials were distinguished, including several classes that reflect important aspects of the playa groundwater chemistry and hydrology. Evaporite crusts containing abundant thenardite (sodium sulfate) were mapped along

James K. Crowley; Simon J. Hook

1996-01-01

76

Mapping playa evaporite minerals and associated sediments in Death Valley, California, with multispectral thermal infrared images  

Microsoft Academic Search

Efflorescent salt crusts and associated sediments in Death Valley, California, were studied with remote-sensing data acquired by the NASA thermal infrared multispectral scanner (TIMS). Nine spectral classes that represent a variety of surface materials were distinguished, including several classes that reflect important aspects of the playa groundwater chemistry and hydrology. Evaporite crusts containing abundant thenardite (sodium sulfate) were mapped along

James K. Crowley; Simon J. Hook

1996-01-01

77

Muhammad Shahir Muttaqin Mohd Fauzi Death Valley, CA: Alluvial Fans in the Making  

E-print Network

. Particularly for the last two decades, alluvial fans are one of the landforms that have been studied very landforms that form a segment of a cone that radiates downslope from the point where the stream leaves 3 of 11 is also famous for its distinctive landforms. Some of the Death Valley landforms that have

Polly, David

78

Stable sulfur isotope hydrogeochemical studies using desert shrubs and tree rings, Death Valley, California, USA  

Microsoft Academic Search

The ?34S values of two dominant xerophytes, Atriplex hymenehytra and Larrea tridentata, in Death Valley, California, vary similarly from +7 to +18, corresponding isotopically to sulfate in the water supplies at a given location. Going radially outwards, tree ring data from a phreatophyte tree, Tamarix aphylla, show a distinct time dependence, with ?34S values increasing from +13.5 to +18 for

Wenbo Yang; Ronald J. Spencer; H. Roy Krouse

1996-01-01

79

Biogeography in the Death Valley region: evidence from springsnails (Hydrobiidae: Tryonia)  

Microsoft Academic Search

Allozyme and mitochondrial DNA variation were analysed to examine evolution of the nine species of springsnails (genus Tiyonia) living in the Death Valley system (Owens and Amargosa basins) of southeastern California and southwestern Nevada. Both allozyme and mtDNA evidence indicate that this highly endemic fauna is non-monophyletic. Species from the upper Amargosa basin comprise a clade most closely related to

Margaret Mulvey; Hsiu-Ping Liu

1999-01-01

80

Isotopic evidence for climatic influence on alluvial-fan development in Death Valley, California  

Microsoft Academic Search

At least three semiarid to arid cycles are recorded by ..delta..¹³C values of organic matter in layers of rock varnishes on surfaces of Hanaupah Canyon and Johnson Canyon alluvial fans, Death Valley, California. These isotopic paleoenvironmental signals are interpreted as indicating major periods of fan aggradation during relatively more humid periods and fan entrenchment during subsequent lengthy arid periods.

Ronald I. Dorn; M. J. DeNiro; H. O. Ajie

1987-01-01

81

Trace element geochemistry in water from selected springs in Death Valley National Park, California  

Microsoft Academic Search

Concentrations of 40 trace elements and other constituents in ground water from springs in Death Valley National Park were measured to investigate whether trace element composition of the ground water can be related to the aquifer materials. Samples from these springs were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) for the trace elements and by ion chromatography (IC) for the

David K. Kreamer; Vernon F. Hodge; Irving Rabinowitz; Kevin H. Johannesson; Klaus J. Stetzenbach

1996-01-01

82

Isotopic evidence for climatic influence on alluvial-fan development in Death Valley, California  

SciTech Connect

At least three semiarid to arid cycles are recorded by ..delta../sup 13/C values of organic matter in layers of rock varnishes on surfaces of Hanaupah Canyon and Johnson Canyon alluvial fans, Death Valley, California. These isotopic paleoenvironmental signals are interpreted as indicating major periods of fan aggradation during relatively more humid periods and fan entrenchment during subsequent lengthy arid periods.

Dorn, R.I.; DeNiro, M.J.; Ajie, H.O.

1987-02-01

83

Surface feature reconnaissance of Death valley, California using skylab S192 multispectral scanner thermal data  

Microsoft Academic Search

Thermal channel data collected with the Skylab S192 multispectral scanner was evaluated for a scene collected over the Death Valley, California area during January 1974. The data collection features of the scanner and the preprocessing of computer compatible precision data products are described. The thermal scene is evaluated for surface feature discrimination using three techniques: 1) false color image construction

A. V. Mazade

1975-01-01

84

Diversity of bacteria and archaea in hypersaline sediment from Death Valley National Park, California  

Technology Transfer Automated Retrieval System (TEKTRAN)

The objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain-specific primers, a region of the 16S rRNA gene was amplified using PCR, and the product was subsequently used to cr...

85

Seafloor-precipitated carbonate fans in the Neoproterozoic Rainstorm Member, Johnnie Formation, Death Valley Region, USA  

E-print Network

Seafloor-precipitated carbonate fans in the Neoproterozoic Rainstorm Member, Johnnie Formation Precipitates Ediacaran Carbon cycle Cm-sized carbonate seafloor fans occur in the Neoproterozoic Rainstorm Member of the Johnnie Formation, Death Valley, USA. The fans formed in a mixed carbonate

Fischer, Woodward

86

Radionuclide transport from yucca Mountain and Inter-basin Flow in Death Valley  

SciTech Connect

Hydrodynamics and the U.S. Geological survey conducted studies to evaluate far-field issues related to potential transport, by ground water, of radionuclide into Inyo County from Yucca Mountain, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. The specific purpose of our research was to acquire geological, subsurface geology, and hydrologic data to: 1. Establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin, 2. Characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and 3. Evaluate the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA. 4. Evaluate the hydraulic connection between the Yucca Mountain repository and Franklin Lake Playa. The hydraulic characterization of the LCA is of critical interest to Inyo County and the U.S. Department of Energy because: 1. The upward gradient in the LCA at Yucca Mountain provides a natural barrier to radionuclide transport, 2. The LCA is a necessary habitat resource for the endangered Devil's Hole pup fish, and 3. The LCA is the primary water supply and source of water to the major springs in Death Valley National Park. This paper presents the results of our study program to evaluate if inter-basin flow exists between the Amargosa and Death Valley Basins through the LCA. The study presents the results of our structural geology analysis of the Southern Funeral Mountain range, geochemical source analysis of spring waters in the region, and a numerical groundwater model to simulate inter-basin flow in the Southern Funeral Mountain range. (authors)

Bredehoeft, J. [The Hydrodynamics Group (United States); Fridrich, C. [U.S. Geological Survey-Denver (United States); King, C.HG.M. [The Hydrodynamics Group, LLC (United States)

2007-07-01

87

Effects of Groundwater Development on Uranium: Central Valley, California, USA  

USGS Publications Warehouse

Uranium (U) concentrations in groundwater in several parts of the eastern San Joaquin Valley, California, have exceeded federal and state drinking water standards during the last 20 years. The San Joaquin Valley is located within the Central Valley of California and is one of the most productive agricultural areas in the world. Increased irrigation and pumping associated with agricultural and urban development during the last 100 years have changed the chemistry and magnitude of groundwater recharge, and increased the rate of downward groundwater movement. Strong correlations between U and bicarbonate suggest that U is leached from shallow sediments by high bicarbonate water, consistent with findings of previous work in Modesto, California. Summer irrigation of crops in agricultural areas and, to lesser extent, of landscape plants and grasses in urban areas, has increased Pco2 concentrations in the soil zone and caused higher temperature and salinity of groundwater recharge. Coupled with groundwater pumping, this process, as evidenced by increasing bicarbonate concentrations in groundwater over the last 100 years, has caused shallow, young groundwater with high U concentrations to migrate to deeper parts of the groundwater system that are tapped by public-supply wells. Continued downward migration of U-affected groundwater and expansion of urban centers into agricultural areas will likely be associated with increased U concentrations in public-supply wells. The results from this study illustrate the potential longterm effects of groundwater development and irrigation-supported agriculture on water quality in arid and semiarid regions around the world.

Jurgens, Bryant C.; Fram, Miranda S.; Belitz, Kenneth; Burow, Karen R.; Landon, Matthew K.

2009-01-01

88

Comparison of basal Silurian quartzarenites in Great Valley and Valley and Ridge provinces of central Appalachians  

SciTech Connect

Throughout the Valley and Ridge province of the central Appalachians, the basal Silurian units are the Tuscarora Sandstone (quartzarenite), Rose Hill (Clinton) Formation (shale), and Keefer Sandstone (quartz subgraywacke). In the Great Valley province to the east, the basal Silurian is represented by a single quartzarenite unit, the Massanutten Sandstone. Based on similar thicknesses and stratigraphic positions, it has been assumed that the Massanutten section is equivalent to the Lower Silurian section in the Valley and ridge. Very little work has been done on the petrography of these two sections to see if there are similarities in terms of depositional environment and provenance to support this correlation. The purpose of this study is to compare the quartzarenite portions of the two sections by means of cathodoluminescence. Cathodoluminescence allows characterization of the source terrane (high versus low-temperature quartz) for a sandstone based on the luminescent colors of the quartz grains. Overall, the ratio of brown to blue luminescing quartz in the Tuscarora differs from that of the Massanutten, suggesting a different source area with more low-temperature quartz supplied to the Tuscarora. Furthermore, within the Massanutten, the ratio of brown to blue quartz decreases from the bottom to the top of the section, consistent with an increased input of high-grade metamorphic or igneous quartz through time. The possible differences in source terranes for the Tuscarora and Massanutten Sandstones are in general agreement with paleogeographic models that have been proposed for the area.

Suter, T.D.

1987-05-01

89

Insiders Views of the Valley of Death Behavioral and Institutional Perspectives  

SciTech Connect

Valley of death describes the metaphorical depths to which promising science and technology too often plunge, never to emerge and reach their full potential. Behavioral and institutional perspectives help in understanding the implications of choices that inadvertently lead into rather than over the valley of death. A workshop conducted among a diverse set of scientists, managers, and technology transfer staff at a U.S. national laboratory is a point of departure for discussing behavioral and institutional elements that promote or impede the pathway from research toward use, and for suggesting actionable measures that can facilitate the flow of information and products from research toward use. In the complex systems that comprise research institutions, where competing pressures can create barriers to information or technology transfer, one recommendation is to re-frame the process as a more active ushering toward use.

Wolfe, Amy K [ORNL] [ORNL; Bjornstad, David J [ORNL] [ORNL; Shumpert, Barry L [ORNL] [ORNL; Wang, Stephanie [ORNL] [ORNL; Lenhardt, W Christopher [ORNL] [ORNL; Campa Ayala, Maria F [ORNL] [ORNL

2014-01-01

90

Ground-Water Modeling of the Death Valley Region, Nevada and California  

USGS Publications Warehouse

The Death Valley regional ground-water flow system (DVRFS) of southern Nevada and eastern California covers an area of about 100,000 square kilometers and contains very complex geology and hydrology. Using a computer model to represent the complex system, the U.S. Geological Survey simulated ground-water flow in the Death Valley region for use with U.S. Department of Energy projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada.

Belcher, W.R.; Faunt, C.C.; Sweetkind, D.S.; Blainey, J.B.; San Juan, C. A.; Laczniak, R.J.; Hill, M.C.

2006-01-01

91

Geochemical constraints on mode of extension in the Death Valley region  

SciTech Connect

The petrographic, chemical, and isotopic characteristics of synex-tensional Miocene-Pliocene volcanic rocks of the Nova Formation Death Valley area, record interaction of three components. Two of these are ancient crust and enriched mantle; they have been recognized previously in the Basin and Range province. The third component is isotopically similar to rocks of the Sierra Nevada batholith exposed to the west of the study area. The authors interpret this source to be the mantle lithosphere and/or lower crust of the Sierra Nevada batholith that was emplaced beneath the Death Valley area by extensional deformation. This is consistent with 150 to 250 km of extension across the southern Basin and Range province inferred from other evidence, and supports the conclusions of workers who suggest that the dominant mode of crustal extension in this area is simple shear with large amounts of lateral lithospheric transport.

Walker, J.D.; Coleman, D.S. (Univ. of Kansas, Lawrence (United States))

1991-10-01

92

Quantitative analysis of surface characteristics and morphology in Death Valley, California using AIRSAR data  

NASA Technical Reports Server (NTRS)

The Jet Propulsion Laboratory Airborne Synthetic Aperture Radar (JPL-AIRSAR) is used to collect full polarimetric measurements at P-, L-, and C-bands. These data are analyzed using the radar analysis and visualization environment (RAVEN). The AIRSAR data are calibrated using in-scene corner reflectors to allow for quantitative analysis of the radar backscatter. RAVEN is used to extract surface characteristics. Inversion models are used to calculate quantitative surface roughness values and fractal dimensions. These values are used to generate synthetic surface plots that represent the small-scale surface structure of areas in Death Valley. These procedures are applied to a playa, smooth salt-pan, and alluvial fan surfaces in Death Valley. Field measurements of surface roughness are used to verify the accuracy.

Kierein-Young, K. S.; Kruse, F. A.; Lefkoff, A. B.

1992-01-01

93

Three-dimensional model of the late Cenozoic history of the Death Valley region, southeastern California  

Microsoft Academic Search

The accumulation of a large database on the timing and kinematics of late Cenozoic deformation in the Death Valley region of southeastern California indicates a complex three-dimensional history. On the basis of paleogeographic reconstructions we suggest the system was initiated as a localized pull-apart between two conjugate strike-slip faults, the Garlock and Furnace Creek faults, and evolved into a system

Laura Serpa; Terry L. Pavlis

1996-01-01

94

200 k.y. paleoclimate record from Death Valley salt core  

Microsoft Academic Search

A 186-m-long core (DV93-1) from Death Valley, California, composed of interbedded salts and muds contains a 200 k.y. record of closed-basin environments and paleoclimates, interpreted on the basis of sedimentology, ostracodes, homogenization temperatures of fluid inclusions in halite, and correlation with shoreline tufa. The 200 k.y. paleoclimate record is dominated by two dry and\\/or warm and wet and cold cycles

Tim K. Lowenstein; Jianren Li; Christopher Brown; Sheila M. Roberts; Teh-Lung Ku; Shangde Luo; Wenbo Yang

1999-01-01

95

Interbasin flow revisited: The contribution of local recharge to high-discharge springs, Death Valley, CA  

Microsoft Academic Search

Springs in the Furnace Creek area (Texas, Travertine, and Nevares Springs) of Death Valley National Park exhibit high discharge rates and depleted ?18OVSMOW (??13) and ?DVSMOW (??102) values. Isotopic depletion of this magnitude and large spring fluxes (?10,000L\\/min) suggests that modern local recharge in the arid Furnace Creek drainage cannot be responsible for spring fluxes. An alternate explanation, interbasin flow,

Katherine Anderson; Stephen Nelson; Alan Mayo; David Tingey

2006-01-01

96

Stratigraphic investigations of carbon isotope anomalies and Neoproterozoic ice ages in Death Valley, California  

Microsoft Academic Search

An unusual richness of biogeochemical events is recorded in Neoproterozoic- Cambrian strata of the Death Valley re- gion, California, United States. Eight neg- ative carbon isotope (d13C) excursions are found in carbonate units between 1.08 Ga and the Precambrian\\/Cambrian boundary; four of these excursions occur in carbonates that contain textural features similar to those found globally in postglacial ''cap carbonates''

Frank A. Corsetti; Alan J. Kaufman

2003-01-01

97

Discrimination of geologic units in Death Valley using dual frequency and polarization imaging radar data  

Microsoft Academic Search

Simultaneous analysis of dual frequency and dual polarization radar imagery of a portion of Death Valley, California has yielded a nearly complete discrimination of surficial geologic units. Radar imagery in like polarized L-band (i.e., 25 cm wavelength), crosspolarized L-band and like polarized X-band (i.e., 3 cm wavelength) were digitally combined and ratioed to enhance the variation in the backscatter cross-section

M. Daily; C. Elachi; T. Farr; G. Schaber

1978-01-01

98

Geochemistry and petrogenesis of Proterozoic diabase in the southern Death Valley region of California  

Microsoft Academic Search

Diabase sills and dikes of Proterozoic age intrude crystalline basement and the overlying Crystal Spring Formation in the southern Death Valley region of California. Despite pervasive deuteric alteration, analyses of relict plagioclase (An66-45), titaniferous augite, and ilmenite permit the calculation of initial crystallization temperatures of 1,16525 C for plagioclase and 1,11025 C for augite with an oxygen fugacity of 10-11

Janet G. Hammond

1986-01-01

99

Geologic Map of the Death Valley Ground-water Model Area, Nevada and California  

Microsoft Academic Search

The purpose of this map is to provide the surface expression of the geology in the Death Valley ground-water model area to be incorporated initially into a 3-D geologic framework model and eventually into a transient ground-water flow model by the U.S. Geological Survey (D'Agnese, 2000; D'Agnese and Faunt, 1999; Faunt and others, 1999; and O'Brien and others, 1999). This

J. B. Workman; C. M. Menges; W. R. Page; E. M. Taylor; E. B. Ekren; P. D. Rowley; G. L. Dixon; R. A. Thompson; L. A. Wright

2003-01-01

100

Integration of AIRSAR and AVIRIS data for Trail Canyon alluvial fan, Death Valley, California  

NASA Technical Reports Server (NTRS)

Combining quantitative geophysical information extracted from the optical and microwave wavelengths provides complementary information about both the surface mineralogy and morphology. This study combines inversion results from two remote sensing instruments, a polarimetric synthetic aperture radar, AIRSAR, and an imaging spectrometer, AVIRIS, for Trail Canyon alluvial fan in Death Valley, California. The NASA/JPL Airborne Synthetic Aperture Radar (AIRSAR) is a quad-polarization, three frequency instrument. AIRSAR collects data at C-band = 5.66 cm, L-band = 23.98 cm, and P-band = 68.13 cm. The data are processed to four-looks and have a spatial resolution of 10 m and a swath width of 12 km. The AIRSAR data used in this study were collected as part of the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley on 9/14/89. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is a NASA/JPL instrument that flies in an ER-2 aircraft at an altitude of 20 km. AVIRIS uses four spectrometers to collect data in 224 spectral channels from 0.4 micrometer to 2.45 micrometer. The width of each spectral band is approximately 10 nm. AVIRIS collects data with a swath width of 11 km and a pixel size of 20 m. The AVIRIS data used in this study were collected over Death Valley on 5/31/92.

Kierein-Young, Kathryn S.

1995-01-01

101

Aeromagnetic map of the Death Valley ground-water model area, Nevada and California  

SciTech Connect

This aeromagnetic map of the Death Valley ground-water model area was prepared from numerous separate aeromagnetic surveys that were gridded, merged, and described by Hildenbrand and Kucks (1988) and by McCafferty and Grauch (1997). These data are available in grid format from the EROS Data Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, and from the National Geophysical Data Center, 325 Broadway, E/GC4, Boulder, Colo., 80303. Magnetic investigations of the Death Valley ground-water basin are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency Agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwest Nevada and adjacent parts of California (Blakely and others, 2000b). The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W.

Ponce, D.A.; Blakely, R.J.

2002-03-12

102

In-Situ Arsenic Remediation in Carson Valley, Douglas County, West-Central Nevada  

E-print Network

In-Situ Arsenic Remediation in Carson Valley, Douglas County, West-Central Nevada Scientific County U.S. Department of the Interior U.S. Geological Survey #12;#12;In-Situ Arsenic Remediation.G., and Welch, A.H., 2010, In-situ arsenic remediation in Carson Valley, Douglas County, west-central Nevada: U

103

COMMUNITY AND EDAPHIC ANALYSIS OF MIXED OAK FORESTS IN RIDGE AND VALLEY PROVINCE OF CENTRAL PENNSYLVANIA  

E-print Network

PENNSYLVANIA Gregory J. Nowacki and Marc D. Abrams 1 Abstract: Forty-two relatively undisturbed mixed oak stands on nine different physiographic units in the Ridge and Valley Province of central Pennsylvania sites. INTRODUCTION The topography of Ridge and Valley Province of central Pennsylvania leads

Abrams, Marc David

104

An Impact Crater in Palm Valley, Central Australia?  

E-print Network

We explore the origin of a ~280 m wide, heavily eroded circular depression in Palm Valley, Northern Territory, Australia using gravity, morphological, and mineralogical data collected from a field survey in September 2009. From the analysis of the survey, we debate probable formation processes, namely erosion and impact, as no evidence of volcanism is found in the region or reported in the literature. We argue that the depression was not formed by erosion and consider an impact origin, although we acknowledge that diagnostics required to identify it as such (e.g. meteorite fragments, shatter cones, shocked quartz) are lacking, leaving the formation process uncertain. We encourage further discussion of the depression's origin and stress a need to develop recognition criteria that can help identify small, ancient impact craters. We also encourage systematic searches for impact craters in Central Australia as it is probable that many more remain to be discovered.

Hamacher, Duane W; O'Neill, Craig; Britton, Tui R

2012-01-01

105

A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques  

SciTech Connect

In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km{sup 2} along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

Faunt, C.C.; D`Agnese, F.A.; Turner, A.K.

1997-12-31

106

A Hydrogeologic Map of the Death Valley Region, Nevada and California, Developed Using GIS Techniques  

USGS Publications Warehouse

In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km 2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

Faunt, Claudia C.; D'Agnese, Frank A.; Turner, A. Keith

1997-01-01

107

Appraisal of the water resources of Death Valley, California-Nevada  

USGS Publications Warehouse

The hydrologic system in Death Valley is probably in a steady-state condition--that is, recharge and discharge are equal, and net changes in the quantity of ground water in storage are not occurring. Recharge to ground water in the valley is derived from interbasin underflow and from local precipitation. The two sources may be of the same magnitude. Ground water beneath the valley moves toward the lowest area, a 200-square-mile saltpan, much of which is underlain by rock salt and other saline minerals, probably to depths of hundreds of feet or even more than 1,000 feet. Some water discharges from the saltpan by evaportranspiration. Water beneath the valley floor, excluding the saltpan, typically contains between 3,000 and 5,000 milligrams per liter of dissolved solids. Water from most springs and seeps in the mountains contains a few hundred to several hundred milligrams per liter of dissolved solids. Water from large springs that probably discharge from interbasin flow systems typically contains between 500 and 1,000 milligrams per liter dissolved solids. Present sites of intensive use by man are supplied by springs, with the exception of the Stovepipe Wells Hotel area. Potential sources of supply for this area include (1) Emigrant Spring area, (2) Cottonwood Spring, and (3) northern Mesquite Flat. (Woodard-USGS)

Miller, Glenn Allen

1977-01-01

108

Interbasin flow in the Great Basin with special reference to the southern Funeral Mountains and the source of Furnace Creek springs, Death Valley, California, U.S.  

USGS Publications Warehouse

Interbasin flow in the Great Basin has been established by scientific studies during the past century. While not occurring uniformly between all basins, its occurrence is common and is a function of the hydraulic gradient between basins and hydraulic conductivity of the intervening rocks. The Furnace Creek springs in Death Valley, California are an example of large volume springs that are widely accepted as being the discharge points of regional interbasin flow. The flow path has been interpreted historically to be through consolidated Paleozoic carbonate rocks in the southern Funeral Mountains. This work reviews the preponderance of evidence supporting the concept of interbasin flow in the Death Valley region and the Great Basin and addresses the conceptual model of pluvial and recent recharge [Nelson, S.T., Anderson, K., Mayo, A.L., 2004. Testing the interbasin flow hypothesis at Death Valley, California. EOS 85, 349; Anderson, K., Nelson, S., Mayo, A., Tingey, D., 2006. Interbasin flow revisited: the contribution of local recharge to high-discharge springs, Death Valley, California. Journal of Hydrology 323, 276-302] as the source of the Furnace Creek springs. We find that there is insufficient modern recharge and insufficient storage potential and permeability within the basin-fill units in the Furnace Creek basin for these to serve as a local aquifer. Further, the lack of high sulfate content in the spring waters argues against significant flow through basin-fill sediments and instead suggests flow through underlying consolidated carbonate rocks. The maximum temperature of the spring discharge appears to require deep circulation through consolidated rocks; the Tertiary basin fill is of insufficient thickness to generate such temperatures as a result of local fluid circulation. Finally, the stable isotope data and chemical mass balance modeling actually support the interbasin flow conceptual model rather than the alternative presented in Nelson et al. [Nelson, S.T., Anderson, K., Mayo, A.L., 2004. Testing the interbasin flow hypothesis at Death Valley, California. EOS 85, 349] and Anderson et al. [Anderson, K., Nelson, S., Mayo, A., Tingey, D., 2006. Interbasin flow revisited: the contribution of local recharge to high-discharge springs, Death Valley, California. Journal of Hydrology 323, 276-302]. In light of these inconsistencies, interbasin flow is the only readily apparent explanation for the large spring discharges at Furnace Creek and, in our view, is the likely explanation for most large volume, low elevation springs in the Great Basin. An understanding of hydrogeologic processes that control the rate and direction of ground-water flow in eastern and central Nevada is necessary component of regional water-resource planning and management of alluvial and bedrock aquifers.

Belcher, W.R.; Bedinger, M.S.; Back, J.T.; Sweetkind, D.S.

2009-01-01

109

Mapping playa evaporite minerals with AVIRIS data: A first report from death valley, California  

USGS Publications Warehouse

Efflorescent salt crusts in Death Valley, California, were mapped by using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. Eight different saline minerals were remotely identified, including three borates, hydroboracite, pinnoite, and rivadavite, that have not been previously reported from the Death Valley efflorescent crusts. The three borates are locally important phases in the crusts, and at least one of the minerals, rivadavite, appears to be forming directly from brine. Borates and other evaporite minerals provide a basis for making remote chemical measurements of desert hydrologic systems. For example, in the Eagle Borax Spring area, the AVIRIS mineral maps pointed to elevated magnesium and boron levels in the ground waters, and to the action of chemical divides causing subsurface fractionation of calcium. Many other chemical aspects of playa brines should have an expression in the associated evaporite assemblages. Certain anhydrous evaporites, including anhydrite, glauberite, and thenardite, lack absorption bands in the visible and near-infrared wavelength range, and crusts composed of these minerals could not be characterized by using AVIRIS. In these situations, thermal-infrared remote sensing data may complement visible and near-infrared data for mapping evaporites. Another problem occurred in wet areas of Death Valley, where water absorption caused low signal levels in the 2.0-2.5 ??m wavelength region that obscured any spectral features of evaporite minerals. Despite these difficulties, the results of this study demonstrate the potential for using AVIRIS and other imaging spectrometer data to study playa chemistry. Such data can be useful for understanding chemical linkages between evaporites and ground waters, and will facilitate studies of how desert ground-water regimes change through time in response to climatic and other variables. ?? 1993.

Crowley, J.K.

1993-01-01

110

Isostatic gravity map of the Death Valley ground-water model area, Nevada and California  

SciTech Connect

Gravity investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W. An isostatic gravity map of the Death Valley ground-water model was prepared from over 40,000 gravity stations, most of which are publicly available on a CD-ROM of gravity data of Nevada (Ponce, 1997). The map also includes gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1998; Morin and Blakely, 1999). A subset of these gravity data in the Nevada Test Site and vicinity were described in detail by Harris and others (1989) who included information on gravity meters used, dates of collection, sources, descriptions of base stations, plots of data, and digital and paper lists of principal facts. For display purposes only, gravity data within Yucca Flat were thinned by a factor of 10. The digital gravity data set was gridded at an interval of 400 m using a computer program (Webring, 1981) based on a minimum curvature algorithm by Briggs (1974). The resulting grid was then interpolated to a 200-m grid to minimize pixel size, and then it was color contoured.

Ponce, D.A.; Blakely, R.J.; Morin, R.L.; Mankinen, E.A.

2002-03-12

111

AVIRIS study of Death Valley evaporite deposits using least-squares band-fitting methods  

NASA Technical Reports Server (NTRS)

Minerals found in playa evaporite deposits reflect the chemically diverse origins of ground waters in arid regions. Recently, it was discovered that many playa minerals exhibit diagnostic visible and near-infrared (0.4-2.5 micron) absorption bands that provide a remote sensing basis for observing important compositional details of desert ground water systems. The study of such systems is relevant to understanding solute acquisition, transport, and fractionation processes that are active in the subsurface. Observations of playa evaporites may also be useful for monitoring the hydrologic response of desert basins to changing climatic conditions on regional and global scales. Ongoing work using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data to map evaporite minerals in the Death Valley salt pan is described. The AVIRIS data point to differences in inflow water chemistry in different parts of the Death Valley playa system and have led to the discovery of at least two new North American mineral occurrences. Seven segments of AVIRIS data were acquired over Death Valley on 31 July 1990, and were calibrated to reflectance by using the spectrum of a uniform area of alluvium near the salt pan. The calibrated data were subsequently analyzed by using least-squares spectral band-fitting methods, first described by Clark and others. In the band-fitting procedure, AVIRIS spectra are fit compared over selected wavelength intervals to a series of library reference spectra. Output images showing the degree of fit, band depth, and fit times the band depth are generated for each reference spectrum. The reference spectra used in the study included laboratory data for 35 pure evaporite spectra extracted from the AVIRIS image cube. Additional details of the band-fitting technique are provided by Clark and others elsewhere in this volume.

Crowley, J. K.; Clark, R. N.

1992-01-01

112

Mapping playa evaporite minerals and associated sediments in Death Valley, California, with multispectral thermal infrared images  

USGS Publications Warehouse

Efflorescent salt crusts and associated sediments in Death Valley, California, were studied with remote-sensing data acquired by the NASA thermal infrared multispectral scanner (TIMS). Nine spectral classes that represent a variety of surface materials were distinguished, including several classes that reflect important aspects of the playa groundwater chemistry and hydrology. Evaporite crusts containing abundant thenardite (sodium sulfate) were mapped along the northern and eastern margins of the Cottonball Basin, areas where the inflow waters are rich in sodium. Gypsum (calcium sulfate) crusts were more common in the Badwater Basin, particularly near springs associated with calcic groundwaters along the western basin margin. Evaporite-rich crusts generally marked areas where groundwater is periodically near the surface and thus able to replenish the crusts though capillary evaporation. Detrital silicate minerals were prevalent in other parts of the salt pan where shallow groundwater does not affect the surface composition. The surface features in Death Valley change in response to climatic variations on several different timescales. For example, salt crusts on low-lying mudflats form and redissolve during seasonal-to-interannual cycles of wetting and desiccation. In contrast, recent flooding and erosion of rough-salt surfaces in Death Valley probably reflect increased regional precipitation spanning several decades. Remote-sensing observations of playas can provide a means for monitoring changes in evaporite facies and for better understanding the associated climatic processes. At present, such studies are limited by the availability of suitable airborne scanner data. However, with the launch of the Earth Observing System (EOS) AM-1 Platform in 1998, multispectral visible/near-infrared and thermal infrared remote-sensing data will become globally available. Copyright 1996 by the American Geophysical Union.

Crowley, J.K.; Hook, S.J.

1996-01-01

113

An evaluation of Skylab (EREP) remote sensing techniques applied to investigation of crustal structure. [Death Valley and Greenwater Valley (CA)  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. A study of Greenwater Valley indicates that the valley is bounded on the north and east by faults, on the south by a basement high, and on the west by the dip slope of the black mountains, movement of ground water from the valley is thus Movement of ground water from the valley is thus restricted, indicating the valley is a potential water reservoir.

Bechtold, I. C. (principal investigator)

1974-01-01

114

The Valley of Death in anticancer drug development: a re-assessment  

PubMed Central

The past decade has seen an explosion in our understanding of cancer biology and with it many new potential disease targets. Yet our ability to translate these advances into therapies is poor, with a failure rate approaching 90%. Much discussion has been devoted to this so-called Valley of Death in anticancer drug development, but the problem persists. Could we have overlooked some straight-forward explanations to this highly complex problem? Important aspects of tumor physiology, drug pharmacokinetics, preclinical models, drug delivery, and clinical translation are not often emphasized and could be critical. This perspective summarizes current views on the problem and suggests feasible alternatives. PMID:22410081

Adams, David J.

2012-01-01

115

Mapping alluvial fans in Death Valley, California, using multichannel thermal infrared images  

NASA Technical Reports Server (NTRS)

Alluvial fans have been mapped in Death Valley, California using NASA's 8-12 micron six-channel airborne Thermal Infrared Multispectral Scanner (TIMS). Both composition and relative age differences were recognized. Age unit boundries are generally consistent with those obtained by conventional mapping. Composition was verified by field investigation and comparison with existing geologic maps. Bedrock and its young derived fan gravels have similar emissivities. The original composition of the fans is modified by differential erosion and weathering, permitting relative age mapping with TIMS.

Gillespie, A. R.; Kahle, A. B.; Pallluconi, F. D.

1984-01-01

116

Declining rock movement at Racetrack Playa, Death Valley National Park: An indicator of climate change?  

NASA Astrophysics Data System (ADS)

We have inspected Racetrack Playa at Death Valley over the last 7 years and have not observed major episodes of rock movement and trail generation. We compare this null observation with the literature record of the rock movement using a Monte Carlo method and find 4-to-1 odds that the rock movement probability has systematically declined. This statistically significant drop in movement rate may indicate a change in the probability of the required conditions for movement: we note decline in the occurrence of strong winds and in ice-forming cold in nearby weather records. Rock movement and trail formation may serve as an indicator of climate change.

Lorenz, Ralph D.; Jackson, Brian K.

2014-04-01

117

Stable sulfur isotope hydrogeochemical studies using desert shrubs and tree rings, Death Valley, California, USA  

SciTech Connect

The {delta}{sup 34}S values of two dominant xerophytes, Atriplex hymenehytra and Larrea tridentata, in Death Valley, California, vary similarly from +7 to +18{per_thousand}, corresponding isotopically to sulfate in the water supplies at a given location. Going radially outwards, tree ring data from a phreatophyte tree, Tamarix aphylla, show a distinct time dependence, with {delta}{sup 34}S values increasing from +13.5 to +18{per_thousand} for soluble sulfate and from +12 to +17% for total sulfur. These data are interpreted in terms of sulfur sources, water sources and flow paths, and tree root growth. 32 refs., 3 figs., 3 tabs.

Yang, Wenbo; Spencer, R.J.; Krouse, H.R. [Univ. of Calgary (Canada)] [Univ. of Calgary (Canada)

1996-08-01

118

Description of Tylenchorhynchus thermophilus n. sp. (Nematoda: Tylenchina) from Saltgrass in Death Valley, California.  

PubMed

A stunt nematode, Tylenchorhynchus thermophilus n. sp., is described and illustrated from soil collected around roots of saltgrass (Distichlis spicata) in Death Valley, California. It is distinguished from the similar species, T. ewingi, T. mexicanus, and T. mashoodi, in having a longer female body, longer tail with more annules, and larger phasmids. Physical and chemical analysis of soil from saltgrass roots showed it to consist of 71% sand and possess high salinity (salt content of 0.51%) and a pH of 9.3. PMID:19277294

Golden, A M; Baldwin, J G; Mundo-Ocampo, M

1995-09-01

119

Geological study of uranium potential of the Kingston Peak Formation, Death Valley Region, California  

SciTech Connect

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak quadrangles. Radiometric suveys of the area were conducted using gamma ray spectrometers. Samples of the conglomerate were analyzed using delayed neutron, neutron activation, atomic absorption, and LECO analysis. It is concluded that uranium mineralization in the Favorable Submember is significant and further exploration is warranted. The monazite-fenotime related uranium and thorium mineralization in the Mountain Girl quartz pebble conglomerate is of no economic interest. (DMC)

Carlisle, D.; Kettler, R.M.; Swanson, S.C.

1980-09-01

120

From Research to Flight: Surviving the TRL Valley of Death for Robotic and Human Space Exploration  

NASA Technical Reports Server (NTRS)

There must be a plan or opportunities for flight validation: a) To reduce the bottleneck of new technologies at the TRL Valley of Death; b) To allow frequent infusion of new technologies into flight missions. Risk must be tolerated for new technology flight experiments. Risk must also be accepted on early-adopting missions to enable new capabilities. Fundamental research is critical to taking the next giant leap in the scientific exploration of space. Technology push is often required to meet current mission requirements. Technology management requires more than issuing NRAs and overseeing contracts.

Johnson, Les

2009-01-01

121

Identification of carotenoids in ancient salt from Death Valley, Saline Valley, and Searles Lake, California, using laser Raman spectroscopy.  

PubMed

Carotenoids are common components of many photosynthetic organisms and are well known from the red waters of hypersaline ecosystems where they are produced by halophilic algae and prokaryotes. They are also of great interest as biomarkers in extraterrestrial samples. Few laser Raman spectroscopy studies have examined ancient field samples, where pigments and microscopic life are less defined. Here, we have identified carotenoids in ancient halite brine inclusions, 9?ka to 1.44?Ma in age, from borehole cores taken from Death Valley, Saline Valley, and Searles Lake, California, for the first time with laser Raman spectroscopy. Carotenoids occurred in fluid inclusions as colorless to red-brown amorphous and crystalline masses associated with spheroidal algal cells similar in appearance to the common halophilic alga Dunaliella. Spectra from carotenoid standards, including ?-carotene, lycopene, and lutein, were compared to microscopically targeted carotenoids in fluid inclusions. Carotenoids produced characteristic bands in the Raman spectrum, 1000-1020?cm? (v?), 1150-1170?cm? (v?), and 1500-1550?cm? (v?), when exposed to visible laser excitation. Laser Raman analyses confirmed the presence of carotenoids with these characteristic peaks in ancient halite. A number of band sets were repeated at various depths (ages), which suggests the stability of this class of organic molecules. Carotenoids appear well preserved in ancient salt, which supports other observations, for example, preserved DNA and live cells, that fluid inclusions in buried halite deposits preserve intact halophilic microbial ecosystems. This work demonstrates the value of laser Raman spectroscopy and carotenoids in extraterrestrial exploration for remnants of microbial life. PMID:24283928

Winters, Y D; Lowenstein, T K; Timofeeff, M N

2013-11-01

122

A Larger Volcanic Field About Yucca Mountain: New Geochemical Data From the Death Valley Volcanic Field, Inyo County California  

NASA Astrophysics Data System (ADS)

Volcanism is an important issue for the characterization of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Due to recent legal decisions that now require DOE to evaluate hazards over both 10,000 year and 1,000,000 year compliance periods, the definition of the area of interest for calculation of disruption probability and a knowledge of the volcanic process have become more important. New geochemical data for the Death Valley volcanic field in the Greenwater Range in Inyo County, California indicate that the Death Valley field and the volcanoes about Yucca Mountain are parts of the same volcanic field. The Death Valley field is just 35 km south of Yucca Mountain and only 20 km south of buried volcanoes in the Amargosa Valley. Trace elements for both areas show a negative Nb anomaly, but differ in that Death Valley basalt has lower La (70 vs. 130 ppm). Isotopic ratios are remarkably similar and strongly support a link between the Death Valley and Yucca Mountain areas. The isotope ranges for Death Valley are -11.88 to -3.26, 0.706322 to 0.707600, 17.725 to 18.509, 15.512 to 15.587, and 38.237 to 38.854 for epsilon Nd, 87Sr/86Sr, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb respectively. Crater Flat isotope ranges are -13.17 to -5.48, 0.706221 to 0.707851, 18.066 to 18.706, 15.488 to 15.564, and 38.143 to 38.709 for epsilon Nd, 87Sr/86Sr, 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb respectively. Depth of melting calculated using the Fe-Na geobarometer indicates that basalt magma was generated at depths of 135-138 km beneath Death Valley and 115-133 km for Crater Flat indicating asthenospheric melting for both areas. Combining the Death Valley and Yucca Mountain areas into a single volcanic field increases the area of interest for probability calculations by over 1/3 and increases the number of volcanic events by 23. The increased size of the volcanic field and number of volcanoes may result in an increase in the probability of disruption of the repository by an igneous event by as much as two orders of magnitude.

Tibbetts, A. K.; Smith, E. I.

2008-12-01

123

Characterization of the Mid Summer Drought in the Central Valley of Costa Rica, Central America  

NASA Astrophysics Data System (ADS)

The IAS region is characterized by climate features of unique nature, one of them is the Mid-Summer Drought (MSD) or "veranillo", an atmospheric feature rarely observed in other tropical regions. On the Pacific slope of Central America, the precipitation annual cycle is characterized by two rainfall maxima in June and September-October, an extended dry season from November to May, and a secondary precipitation minima during July-August (MSD). Three daily gauge stations records, e.g. La Argentina, Fabio Baudrit and Juan Santamaria, located in the Central Valley of Costa Rica were studied to characterize the MSD from 1937 to 2010. Among the aspects considered are the MSD duration, intensity, timing and seasonal predictability. The modulation of these aspects by climate variability sources as Equatorial Eastern Pacific and Tropical North Atlantic was lately explored, including their interannual and decadal variability. The MSD signal strongly impact social and economic life in the region like energy and the agriculture sector. Additionally, the Central Valley of Costa Rica hosts most of the Costa Rican population with the higher level of exposure and vulnerability to hydro-meteorological hazards.

Alfaro, E.

2013-05-01

124

Effect of faulting on ground-water movement in the Death Valley region, Nevada and California  

SciTech Connect

This study characterizes the hydrogeologic system of the Death Valley region, an area covering approximately 100,000 square kilometers. The study also characterizes the effects of faults on ground-water movement in the Death Valley region by synthesizing crustal stress, fracture mechanics,a nd structural geologic data. The geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. Faulting and associated fracturing is pervasive and greatly affects ground-water flow patterns. Faults may become preferred conduits or barriers to flow depending on whether they are in relative tension, compression, or shear and other factors such as the degree of dislocations of geologic units caused by faulting, the rock types involved, the fault zone materials, and the depth below the surface. The current crustal stress field was combined with fault orientations to predict potential effects of faults on the regional ground-water flow regime. Numerous examples of fault-controlled ground-water flow exist within the study area. Hydrologic data provided an independent method for checking some of the assumptions concerning preferential flow paths. 97 refs., 20 figs., 5 tabs.

Faunt, C.C.

1997-12-31

125

Landforms and landscape evolution in the Skardu, Shigar and Braldu Valleys, Central Karakoram  

Microsoft Academic Search

The Central Karakoram, which includes K2 in Pakistan, is one of the most rapidly rising areas on Earth and exhibits complex topography and extreme relief. Impressive valley fills and glacial landforms are present throughout the valleys. The dynamics of landscape evolution of the region are currently not well understood. Consequently, the landforms were mapped and assessed in the Skardu, Shigar,

Yeong Bae Seong; Michael P. Bishop; Andrew Bush; Penny Clendon; Luke Copland; Robert C. Finkel; Ulrich Kamp; Lewis A. Owen; John F. Shroder

2009-01-01

126

Emission rates of organics from vegetation in California's Central Valley  

NASA Astrophysics Data System (ADS)

Rates of emission of speciated hydrocarbons have been determined for more than 30 of the most dominant (based on acreage) agricultural and natural plant types found in California's Central Valley. These measurements employed flow-through Teflon chambers, sample collection on solid adsorbent and thermal desorption gas chromatography (GC) and GC-mass spectrometry analysis to identify more than 40 individual organic compounds. In addition to isoprene and the monoterpenes, we observed sesquiterpenes, alcohols, acetates, aldehydes, ketones, ethers, esters, alkanes, alkenes and aromatics as emissions from these plant species. Mean emission rates for total monoterpenes ranged from none detected in the case of beans, grapes, rice and wheat, to as high as 12-30 ?g h -1 g -1 for pistachio and tomato (normalized to dry leaf and total biomass, respectively). Other agricultural species exhibiting substantial rates of emission of monoterpenes included carrot, cotton, lemon, orange and walnut. All of the plant species studied showed total assigned compound emission rates in the range between 0.1 and 36 ?g h -1 g -1.

Winer, Arthur M.; Arey, Janet; Atkinson, Roger; Aschmann, Sara M.; Long, William D.; Morrison, C. Lynn; Olszyk, David M.

127

Map showing depth to pre-Cenozoic basement in the Death Valley ground-water model area, Nevada and California  

SciTech Connect

This map shows the depth to pre-Cenozoic basement in the Death Valley ground-water model area. It was prepared utilizing gravity (Ponce and others, 2001), geologic (Jennings and others, 1977; Stewart and Carlson, 1978), and drill-hole information. Geophysical investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency Agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W.

Blakely, R.J.; Ponce, D.A.

2002-03-12

128

Fault pattern at the northern end of the Death Valley - Furnace Creek fault zone, California and Nevada  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The pattern of faulting associated with the termination of the Death Valley-Furnace Creek Fault Zone in northern Fish Lake Valley, Nevada was studied in ERTS-1 MSS color composite imagery and color IR U-2 photography. Imagery analysis was supported by field reconnaissance and low altitude aerial photography. The northwest-trending right-lateral Death Valley-Furnace Creek Fault Zone changes northward to a complex pattern of discontinuous dip slip and strike slip faults. This fault pattern terminates to the north against an east-northeast trending zone herein called the Montgomery Fault Zone. No evidence for continuation of the Death Valley-Furnace Creek Fault Zone is recognized north of the Montgomery Fault Zone. Penecontemporaneous displacement in the Death Valley-Furnace Creek Fault Zone, the complex transitional zone, and the Montgomery Fault Zone suggests that the systems are genetically related. Mercury mineralization appears to have been localized along faults recognizable in ERTS-1 imagery within the transitional zone and the Montgomery Fault Zone.

Liggett, M. A. (principal investigator); Childs, J. F.

1974-01-01

129

Reconnaissance geology of the Central Mastuj Valley, Chitral State, Pakistan  

USGS Publications Warehouse

The Mastuj Valley in Chitral State is a part of the Hindu Kush Range, and is one of the structurally most complicated areas in northern Pakistan. Sedimentary rocks ranging from at least Middle Devonian to Cretaceous, and perhaps Early Tertiary age lie between ridge-forming granodiorite intrusions and are cut by thrust faults. The thrust planes dip 10? to 40? to the north- west. Movement of the upper thrust plates has been toward the southeast relative to the lower blocks. If this area is structurally typical of the Hindu-Kush and Karakoram Ranges, then these mountains are much more tectonically disturbed than previously recorded, and suggest compression on a scale compatible with the hypothesis that the Himalayan, Karakoram, and Hindu Kush Ranges form part of a continental collision zone. The thrust faults outline two plates consisting of distinctive sedimentary rocks. The lower thrust plate is about 3,000 feet thick and consists of the isoclinally folded Upper Cretaceous to perhaps lower Tertiary Reshun Formation. It has overridden the Paleozoic metasedimentary rocks of the Chitral Slate unit. This thrust plate is, in turn, overridden by an 8,000-foot thick sequence consisting largely of Devonian to Carboniferous limestones and quartzites. A key factor in the tectonic processes has been the relatively soft and plastic lithology of the siltstone layers in the Reshun Formation which have acted as lubricants along the principal thrust faults, where they are commonly found today as fault slices and smears. The stratigraphic sequence, in the central Mastuj Valley was tentatively divided into 9 mapped units. The fossiliferous shales and carbonates of the recently defined Shogram Formation and the clastlcs of the Reshun Formation have been fitted into a sequence of sedimentary rocks that has a total thick- ness of at least 13,000 feet and ranges in age from Devonian to Neogene. Minerals of potential economic significance include antimony sulfides which have been mined elsewhere in Chitral, the tungstate, scheelite, which occurs in relatively high concentrations in heavy-mineral fractions of stream sands, and an iron-rich lateritic rock.

Stauffer, Karl W.

1975-01-01

130

Geologic application of thermal inertia imaging using HCMM data. [Death Valley and Piggah Crater, California and Goldfield, Nevada  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The day infrared and visible HCMM satellite data for Death Valley taken on 31 May 1978 were compared with aircraft data of the same area taken in March of the same year. In the visible image, it is possible to note the drying of the valley floor during the two month period between acquisition of the two data sets. On the IR image however, the valley floor remains cool, probably indicating that while the standing water has disappeared, the floor is still moist.

Paley, H. N.; Kahle, A. B. (principal investigators)

1979-01-01

131

76 FR 12756 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act...Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability...Improvement Act of 1992 (CVPIA) and the Reclamation Reform Act of 1982, the Bureau...

2011-03-08

132

76 FR 54251 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act...Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability...Improvement Act of 1992 (CVPIA) and the Reclamation Reform Act of 1982, the Bureau...

2011-08-31

133

ANALYSIS OF MACROINVERTEBRATE ASSEMBLAGES IN RELATION TO ENVIRONMENTAL GRADIENTS AMONG LOTIC HABITATS OF CALIFORNIA'S CENTRAL VALLEY  

EPA Science Inventory

We analyzed relationships between environmental characteristics and macroinvertebrate assemblages in lotic habitats of California's Central Valley with community metric and multivariate statistical approaches. Using canonical ordination analyses, we contrasted results when asse...

134

75 FR 69698 - Central Valley Project Improvement Act, Criteria for Developing Refuge Water Management Plans  

Federal Register 2010, 2011, 2012, 2013, 2014

...for efficient use of water by Federal Wildlife Refuges...Districts that receive water under provisions of the Central Valley Project Improvement Act (CVPIA...format by which Refuge Water Management Plans (Plans...Refuge/ District Water Supply Contracts and...

2010-11-15

135

RELATIONSHIPS BETWEEN ENVIRONMENTAL VARIABLES AND BENTHIC DIATOM ASSEMBLAGES IN CALIFORNIA CENTRAL VALLEY STREAMS (USA)  

EPA Science Inventory

Streams and rivers in the California Central Valley Ecoregion have been substantially modified by human activities. This study examines distributional patterns of benthic diatom assemblages in relation to environmental characteristics in streams and rivers of this region. Benthic...

136

Kinematics at the Intersection of the Garlock and Death Valley Fault Zones, California: Integration of TM Data and Field Studies  

NASA Technical Reports Server (NTRS)

Kinematic relationships at the intersection of the southern Death Valley and Garlock fault zones were examined to identify and delineate the eastern structural boundary between the Mojave and the Basin and Range geologic terrains, and to construct a model for the evolution of this boundary through time. In order to accomplish this, satellite imagery was combined with field investigations to study six areas in the vicinity of the intersection, or possible extensions, of the fault zones. The information gathered from these areas allows the test of various hypotheses that were proposed to explain the interaction between the Death Valley and Garlock fault zones.

Verosub, Kenneth L.; Brady, Roland H., III; Abrams, Michael

1989-01-01

137

Cenozoic tectonic reorganizations of the Death Valley region, southeast California and southwest Nevada  

USGS Publications Warehouse

The Death Valley region, of southeast California and southwest Nevada, is distinct relative to adjacent regions in its structural style and resulting topography, as well as in the timing of basin-range extension. Cenozoic basin-fill strata, ranging in age from greater than or equal to 40 to approximately 2 million years are common within mountain-range uplifts in this region. The tectonic fragmentation and local uplift of these abandoned basin-fills indicate a multistage history of basin-range tectonism. Additionally, the oldest of these strata record an earlier, pre-basin-range interval of weak extension that formed broad shallow basins that trapped sediments, without forming basin-range topography. The Cenozoic basin-fill strata record distinct stratigraphic breaks that regionally cluster into tight age ranges, constrained by well-dated interbedded volcanic units. Many of these stratigraphic breaks are long recognized formation boundaries. Most are angular unconformities that coincide with abrupt changes in depositional environment. Deposits that bound these unconformities indicate they are weakly diachronous; they span about 1 to 2 million years and generally decrease in age to the west within individual basins and regionally, across basin boundaries. Across these unconformities, major changes are found in the distribution and provenance of basin-fill strata, and in patterns of internal facies. These features indicate rapid, regionally coordinated changes in strain patterns defined by major active basin-bounding faults, coincident with step-wise migrations of the belt of active basin-range tectonism. The regionally correlative unconformities thus record short intervals of radical tectonic change, here termed "tectonic reorganizations." The intervening, longer (about 3- to 5-million-year) interval of gradual, monotonic evolution in the locus and style of tectonism are called "tectonic stages." The belt of active tectonism in the Death Valley region has abruptly stepped westward during three successive tectonic reorganizations that intervened between four stages of basin-range tectonism, the youngest of which is ongoing. These three tectonic reorganizations also intervened between four stages of volcanic activity, each of which has been distinct in the compositions of magmas erupted, in eruption rates, and in the locus of volcanic activitywhich has stepped progressively westward, in close coordination with the step-wise migrations in the locus of basin-range extension. The timing of the Cenozoic tectonic reorganizations in the Death Valley region correlates closely with the documented timing of episodic reorganizations of the boundary between the Pacific and North American plates, to the west and southwest. This supports models that explain the widely distributed transtensional tectonism in southwestern North America since approximately 40 million years ago as resulting from traction imposed by the adjacent, divergent Pacific plate.

Fridrich, Christopher J.; Thompson, Ren A.

2011-01-01

138

Surface roughness, radar backscatter, and visible and near-infrared reflectance in Death Valley, California  

NASA Astrophysics Data System (ADS)

The vast alluvial fans of Death Valley, California, provide an ideal environment to examine the remote sensing measurement of geologic surfaces. One of the objectives of the shuttle imaging radar C (SIR C) program in Death Valley is detection of the variation in surface microtopography with age of the surface. We present results of extensive field measurements of surface roughness together with an analysis of the effects of the surface microtopography on radar backscatter and visible and near-infrared (VNIR) reflectance as measured by aircraft and satellite sensors. This subject is addressed in both the forward and inverse sense: surface simulation and forward modeling are used to determine expected roughness effects, while a method of inverse analysis that uses finite impulse response (FIR) filters is used to assess the potential for inversion of multifrequency, polarimetric, synthetic aperture radar (SAR), and multispectral VNIR imagery for surface roughness. The interaction of radar and VNIR radiation with the Death Valley surfaces is complicated. Simple roughness parameters such as rms height, and slope and offset of surface power spectra, do not represent a sufficiently complete description of surface roughness to predict the radar or VNIR signature uniquely. Multiple scattering, which is controlled to a large extent by aspects of the phase of the surface Fourier transform, also exerts a controlling influence on the observed signal. The phase aspect of surface roughness has not been considered in existing roughness characterization. Our inversions demonstrate retrieval of roughness parameters with almost equal success from both SAR data and Landsat thematic mapper (TM) data and indicate much potential for joint SAR/VNIR data analysis. The solutions are not, however, very stable and include effects of additional parameters such as intermediate-scale topography and vegetation cover which masquerade as roughness variation. In designing a stable inversion of more general applicability, the multifrequency and polarimetric aspect of SIR C data is important. Nevertheless, high-resolution roughness recovery will probably require hierarchical analysis of radar and optical images, and also SAR acquisition at multiple look angles and directions.

Weeks, Robin J.; Smith, Milton; Pak, Kyung; Li, Wen-Hao; Gillespie, Alan; Gustafson, Bill

1996-10-01

139

Interpretive geologic cross sections for the Death Valley regional flow system and surrounding areas, Nevada and California  

USGS Publications Warehouse

This report presents a network of 28 geologic cross sections that portray subsurface geologic relations within the Death Valley regional ground-water system, a ground-water basin that encompasses a 3? x 3? area (approximately 70,000 km2) in southern Nevada and eastern California. The cross sections transect that part of the southern Great Basin that includes Death Valley, the Nevada Test Site, and the potential high-level nuclear waste underground repository at Yucca Mountain. The specific geometric relationships portrayed on the cross sections are discussed in the context of four general sub-regions that have stratigraphic similarities and general consistency of structural style: (1) the Nevada Test Site vicinity; (2) the Spring Mountains, Pahrump Valley and Amargosa Desert region; (3) the Death Valley region; and (4) the area east of the Nevada Test Site. The subsurface geologic interpretations portrayed on the cross sections are based on an integration of existing geologic maps, measured stratigraphic sections, published cross sections, well data, and geophysical data and interpretations. The estimated top of pre-Cenozoic rocks in the cross sections is based on inversion of gravity data, but the deeper parts of the sections are based on geologic conceptual models and are more speculative. The region transected by the cross sections includes part of the southern Basin and Range Province, the northwest-trending Walker Lane belt, the Death Valley region, and the northern Mojave Desert. The region is structurally complex, where a locally thick Tertiary volcanic and sedimentary section unconformably overlies previously deformed Proterozoic through Paleozoic rocks. All of these rocks have been deformed by complex Neogene ex-tensional normal and strike-slip faults. These cross sections form a three-dimensional network that portrays the interpreted stratigraphic and structural relations in the region; the sections form part of the geologic framework that will be incorporated in a complex numerical model of ground-water flow in the Death Valley region.

Sweetkind, D.S.; Dickerson, R.P.; Blakely, R.J.; Denning, P.D.

2001-01-01

140

Holocene fluvial geomorphic change in the central Mississippi Valley  

SciTech Connect

Four distinct Mississippi River (MR) channel patterns are distinguished on the basis of geomorphic expression and cross-cutting relationships between the Missouri River mouth and Thebes Gap (TG). In order of decreasing age, they are (1) a multi-channeled braided system superimposed on a sandy substrate that correlates with the Kingston Terrace (KT); (2) a relatively large amplitude, large sinuosity, meandering system; (3) a smaller amplitude, smaller sinuosity, meandering system with a marked increase in associated overbank sheetwash and splays; and, (4) an island-braided pattern aligned with the modern (MR). After the (KT) formed, the (MR) had a net westward migration and episodically decreased in sinuosity. Decreasing sinuosity is possibly in response to a general decrease in sediment yield. Channel pattern changes are bracketed somewhat by available radiocarbon ages and the geomorphic location of archaeological deposit with temporally diagnostic artifacts. The KT formed between about 10,400 and 9800 B.P.; the superimposed braid pattern has fill consisting of Lake Superior source reddish brown clay deposited by large, and possibly catastrophic, floods between 9800 and 9500 B.P. The large sinuosity meandering pattern was active from before 4400 B.P. until about 2400 B.P. at the latest. It was probably initiated millennia earlier. The small sinuosity meandering pattern was initiated by about 2500 B.P. and abandoned before 1100 B.P. The geomorphic mapping is the first component of a geoarchaeological investigation to aid cultural resource management to aid cultural resource management in the central MR Valley. At the same time, it provides some constraints on the origin and age of some long-recognized landforms, such as the TG.

Hajic, E.R. (Illinois State Museum, Springfield, IL (United States))

1992-01-01

141

High-angle origin of the currently low-angle Badwater Turtleback fault, Death Valley, California  

SciTech Connect

The late Cenozoic Badwater Turtleback fault separates an upper plate of volcanic and sedimentary rocks from a lower plate of predominantly mylonitic plutonic and metamorphic rocks. The Turtleback fault, however, is not a single continuous surface, but consists of a least three generations of faults. These faults occur as discrete, crosscutting segments that progressively decrease in age and increase in dip to the west. Therefore, they probably began at moderate to steep angles but rotated to lower angles with extensional strain. If so, lower plate mylonitic rocks also restore to steeper dips and suggest that transport of the upper plate occurred on moderate to steeply dipping surfaces in the middle and upper crust. The crosscutting nature of the fault segments and their initial moderate to steep dips, plus a possible offset marker on one of the segments, are most consistent with moderate amounts of extension in the Death Valley region.

Miller, M.G. (Univ. of Washington, Seattle (USA))

1991-04-01

142

Estimated ground-water discharge by evapotranspiration from Death Valley, California, 1997-2001  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the National Park Service and Inyo County, Calif., collected field data from 1997 through 2001 to accurately estimate the amount of annual ground-water discharge by evapotranspiration (ET) from the floor of Death Valley, California. Multispectral satellite-imagery and National Wetlands Inventory data are used to delineate evaporative ground-water discharge areas on the Death Valley floor. These areas are divided into five general units where ground-water discharge from ET is considered to be significant. Based upon similarities in soil type, soil moisture, vegetation type, and vegetation density; the ET units are salt-encrusted playa (21,287 acres), bare-soil playa (75,922 acres), low-density vegetation (6,625 acres), moderate-density vegetation (5,019 acres), and high-density vegetation (1,522 acres). Annual ET was computed for ET units with micrometeorological data which were continuously measured at six instrumented sites. Total ET was determined at sites that were chosen for their soil- and vegetated-surface conditions, which include salt-encrusted playa (extensive salt encrustation) 0.17 feet per year, bare-soil playa (silt and salt encrustation) 0.21 feet per year, pickleweed (pickleweed plants, low-density vegetation) 0.60 feet per year, Eagle Borax (arrowweed plants and salt grass, moderate-density vegetation) 1.99 feet per year, Mesquite Flat (mesquite trees, high-density vegetation) 2.86 feet per year, and Mesquite Flat mixed grasses (mixed meadow grasses, high-density vegetation) 3.90 feet per year. Precipitation, flooding, and ground-water discharge satisfy ET demand in Death Valley. Ground-water discharge is estimated by deducting local precipitation and flooding from cumulative ET estimates. Discharge rates from ET units were not estimated directly because the range of vegetation units far exceeded the five specific vegetation units that were measured. The rate of annual ground-water discharge by ET for each ET unit was determined by fitting the annual ground-water ET for each site with the variability in vegetation density in each ET unit. The ET rate representing the midpoint of each ET unit was used as the representative value. The rate of annual ground-water ET for the playa sites did not require scaling in this manner. Annual ground-water discharge by ET was determined for all five ET units: salt-encrusted playa (0.13 foot), bare-soil playa (0.15 foot), low-density vegetation (1.0 foot), moderate-density vegetation (2.0 feet), and high-density vegetation (3.0 feet), and an area of vegetation or bare soil not contributing to ground-water discharge unclassified (0.0 foot). The total ground-water discharge from ET for the Death Valley floor is about 35,000 acre-feet and was computed by summing the products of the area of each ET unit multiplied by a corresponding ET rate for each unit.

DeMeo, Guy A.; Laczniak, Randell J.; Boyd, Robert A.; Smith, J. LaRue; Nylund, Walter E.

2003-01-01

143

HELIOTHERMAL LAKE MODEL OF BORATE DEPOSITION IN THE MIOCENE FURNACE CREEK FORMATION, DEATH VALLEY REGION, CALIFORNIA.  

USGS Publications Warehouse

Heliothermal lakes are density-stratified with shallow submerged margins surrounding areally restricted deep pool(s) containing a dense brine overlain by a much less dense brine. The reflective brine interface allows solar energy to be trapped in the dense brine which may warm to over 90 degree C. Carbonate precipitated from the dense brine is the typical sediment produced in warm deep pool. Miocene borate deposits of the Death Valley region are typically contained within areally limited carbonate-rich pods that interfinger with a finely interlaminated (varve-like) mudstone and limestone. Primary borates there are predominately either Na-Ca borates or Ca-borates. This bimodal evaporite assemblage suggests that brine chemistries and (or) crystallization paths varied significantly in temporally and spatially related portions of this apparently continuous lacustrine deposit.

Barker, Charles E.; Barker, James M.

1988-01-01

144

Characterizing the hydrogeologic framework of the Death Valley region, Southern Nevada and California  

USGS Publications Warehouse

Three-dimensional (3-D) hydrogeologic modeling of the complex geology of the Death Valley region requires the application of a number of Geoscientific Information System (GSIS) techniques. This study, funded by United States Department of Energy as a part of the Yucca Mountain Project, focuses on an area of approximately 100,000 square kilometers (three degrees of latitude by three degrees of longitude) and extends up to ten kilometers in depth. The geologic conditions are typical of the Basin and Range province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. GSIS techniques allow the synthesis of geologic, hydrologic and climatic information gathered from many sources, including satellite imagery and published maps and cross-sections. Construction of a 3-D hydrogeological model is possible with the combined use of software products available from several vendors, including traditional GIS products and sophisticated contouring, interpolation, visualization, and numerical modeling packages.

Faunt, Claudia; D'Agnese, Frank; Downey, Joe S.; Turner, A. Keith

1993-01-01

145

Death Valley regional groundwater flow model calibration using optimal parameter estimation methods and geoscientific information systems  

USGS Publications Warehouse

A three-layer Death Valley regional groundwater flow model was constructed to evaluate potential regional groundwater flow paths in the vicinity of Yucca Mountain, Nevada. Geoscientific information systems were used to characterize the complex surface and subsurface hydrogeological conditions of the area, and this characterization was used to construct likely conceptual models of the flow system. The high contrasts and abrupt contacts of the different hydrogeological units in the subsurface make zonation the logical choice for representing the hydraulic conductivity distribution. Hydraulic head and spring flow data were used to test different conceptual models by using nonlinear regression to determine parameter values that currently provide the best match between the measured and simulated heads and flows.

D'Agnese, F. A.; Faunt, C.C.; Hill, M.C.; Turner, A.K.

1996-01-01

146

Paleowind velocity and paleocurrents of pluvial Lake Manly, Death Valley, USA  

NASA Astrophysics Data System (ADS)

Pluvial lake deposits are found throughout western North America and are frequently used to reconstruct regional paleoclimate. In Death Valley, California, USA, we apply the beach particle technique (BPT) of Adams (2003), Sedimentology, 50, 565-577 and Adams (2004), Sedimentology, 51, 671-673 to Lake Manly deposits at the Beatty Junction Bar Complex (BJBC), Desolation Canyon, and Manly Terraces and calculate paleowind velocities of 14-27 m/s. These wind velocities are within the range of present-day wind velocities recorded in the surrounding area. Sedimentary structures and clast provenance at Desolation Canyon and the Manly Terraces indicate sediment transport from north to south. Lake level, based on the elevation of constructional features, indicates that the hill west of the BJBC was an island and that the BJBC spits formed during simple lake regression. The data are consistent with the hypothesis that the present wind regime (velocity and direction) formed the pluvial Lake Manly features.

Knott, Jeffrey R.; Fantozzi, Joanna M.; Ferguson, Kelly M.; Keller, Summer E.; Nadimi, Khadija; Rath, Carolyn A.; Tarnowski, Jennifer M.; Vitale, Michelle L.

2012-09-01

147

GEOLOGY AND ORIGIN OF THE DEATH VALLEY URANIUM DEPOSIT, SEWARD PENINSULA, ALASKA.  

USGS Publications Warehouse

A uranium deposit discovered in 1977 in western Alaska, by means of airborne radiometric data, is the largest known in Alaska on the basis of industry reserve estimates. The deposit is apparently of epigenetic and supergene origin. The uranium was derived from the Cretaceous granite of the Darby pluton that forms part of the western side of Death Valley. Uranium from primary mineralization is in the subsurface in a marginal facies of the Tertiary sedimentary basin where nearshore coarse clastic rocks are interbedded with coal and lacustrine clay. The supergene enrichment is related to a soil horizon at the present ground surface. Extensive exploratory drilling took place from 1979 to 1981. The average grade of the potential ore is 0. 27 percent U//3O//8 and the average thickness is 3 m. The calculated reserves are 1,000,000 lbs U//3O//8; additional drilling would probably add to this figure. Additional study results are discussed.

Dickinson, Kendell A.; Cunningham, Kenneth D.; Ager, Thomas A.

1987-01-01

148

Guidelines for model calibration and application to flow simulation in the Death Valley regional groundwater system  

USGS Publications Warehouse

Fourteen guidelines are described which are intended to produce calibrated groundwater models likely to represent the associated real systems more accurately than typically used methods. The 14 guidelines are discussed in the context of the calibration of a regional groundwater flow model of the Death Valley region in the southwestern United States. This groundwater flow system contains two sites of national significance from which the subsurface transport of contaminants could be or is of concern: Yucca Mountain, which is the potential site of the United States high-level nuclear-waste disposal; and the Nevada Test Site, which contains a number of underground nuclear-testing locations. This application of the guidelines demonstrates how they may be used for model calibration and evaluation, and also to direct further model development and data collection.Fourteen guidelines are described which are intended to produce calibrated groundwater models likely to represent the associated real systems more accurately than typically used methods. The 14 guidelines are discussed in the context of the calibration of a regional groundwater flow model of the Death Valley region in the southwestern United States. This groundwater flow system contains two sites of national significance from which the subsurface transport of contaminants could be or is of concern: Yucca Mountain, which is the potential site of the United States high-level nuclear-waste disposal; and the Nevada Test Site, which contains a number of underground nuclear-testing locations. This application of the guidelines demonstrates how they may be used for model calibration and evaluation, and also to direct further model development and data collection.

Hill, M.C.; D'Agnese, F. A.; Faunt, C.C.

2000-01-01

149

Tectonic map of the Death Valley ground-water model area, Nevada and California  

SciTech Connect

The purpose of this map is to provide tectonic interpretations in the Death Valley ground-water model area to be incorporated into a transient ground-water flow model by the U.S. Geological Survey (D'Agnese, 2000; D'Agnese and Faunt, 1999; Faunt and others, 1999; and O'Brien and others, 1999). This work has been conducted in collaboration with the U.S. Department of Energy in order to assess regional ground-water flow near the Nevada Test Site (NTS) and the potential radioactive waste repository at Yucca Mountain. The map is centered on the NTS and its perimeter encircles the entire boundary of the numerical flow model area, covering a total area of 57,000 square kilometers. This tectonic map is a derivative map of the geologic map of the Death Valley ground-water model, Nevada and California (Workman and others, 2002). Structures portrayed on the tectonic map were selected from the geologic map based upon several criteria including amount of offset on faults, regional significance of structures, fault juxtaposition of rocks with significantly different hydrologic properties, and the hydrologic properties of the structures themselves. Inferred buried structures in the basins were included on the map (blue and light blue dotted lines) based on interpretation of geophysical data (Ponce and others, 2001; Ponce and Blakely, 2001; Blakely and Ponce, 2001). In addition, various regional trends of fault zones have been delineated which are composed of multiple smaller scale features. In some cases, these structures are deeply buried and their location is based primarily on geophysical evidence. In all cases, these zones (shown as broad red and blue stippled bands on the map) are significant structures in the region. Finally, surface exposures of Precambrian crystalline rocks and igneous intrusions of various ages are highlighted (red and blue patterns) on the map; these rocks generally act as barriers to groundwater flow unless significantly fractured.

J.B. Workman; C.M. Menges; W.R. Page; E.B. Ekren; P.D. Rowley; G.L. Dixon

2002-10-17

150

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies  

NASA Technical Reports Server (NTRS)

The Garlock and Death Valley fault zones in SE California are two active strike-slip faults coming together on the east side of the Avawatz Mtns. The kinematics of this intersection, and the possible continuation of either fault zone, are being investigated using a combination of field mapping, and processing and interpretation of remotely sensed image data. Regional and local relationships are derivable from Thematic Mapper data (30 m resolution), including discrimination and relative age dating of alluvial fans, bedrock mapping, and fault mapping. Aircraft data provide higher spatial resolution over more limited areas. Hypotheses being considered are: (1) the Garlock fault extends east of the intersection; (2) the Garlock fault terminates at the intersection and the Death Valley fault continues southeastward; and (3) the Garlock fault has been offset right laterally by the Death Valley fault which continues to the southeast. Preliminary work indicates that the first hypothesis is invalid. From kinematic considerations, image analysis, and field work the third hypothesis is favored. The projected continuation of the Death Valley zone defines the boundary between the Mojave crustal block and the Basin and Range block.

Abrams, Michael; Verosub, Ken; Finnerty, Tony; Brady, Roland

1987-01-01

151

Map showing depth to pre-Cenozoic basement in the Death Valley ground-water model area, Nevada and California  

USGS Publications Warehouse

A depth to basement map of the Death Valley groundwater model area was prepared using over 40,0000 gravity stations as part of an interagency effort by the U.S. Geological Survey and the U.S. Department of Energy to help characterize the geology and hydrology of southwest Nevada and parts of California.

Blakely, R.J.; Ponce, D.A.

2001-01-01

152

Magnetic and clast fabrics as measurements of grain-scale processes within the Death Valley shallow crustal detachment faults  

E-print Network

of shallow-crustal faulting includes fine-grained breccia and clay-rich gouge. Many gouges and breccias have and breccia sampled from low-angle normal (detachment) faults in the Black Mountains, Death Valley, CA. We shear zones. Shallow crustal shear zones are filled with breccia and gouge, fault rocks with clast

Housen, Bernie

153

The effect of rising atmospheric oxygen on carbon and sulfur isotope anomalies in the Neoproterozoic Johnnie Formation, Death Valley, USA  

Microsoft Academic Search

Carbonates within the Rainstorm Member in the terminal Neoproterozoic Johnnie Formation of Death Valley, California record a remarkable negative carbon isotope anomaly to a nadir of near ?11 that accompanies a dramatic rise in trace sulfate abundance and fall of carbonate associated sulfate ?34S values. The carbonates, including the laterally extensive Johnnie Oolite, were deposited during marine flooding

Alan J. Kaufman; Frank A. Corsetti; Michael A. Varni

2007-01-01

154

Faulting at Mormon Point, Death Valley, California: A low-angle normal fault cut by high-angle faults  

Microsoft Academic Search

New geophysical and fault kinematic studies indicate that late Cenozoic basin development in the Mormon Point area of Death Valley, California, was accommodated by fault rotations. Three of six fault segments recognized at Mormon Point are now inactive and have been rotated to low dips during extension. The remaining three segments are now active and moderately to steeply dipping. From

Charles Keener; Laura Serpa; Terry L. Pavlis

1993-01-01

155

Bacillus vallismortis sp. nov., a close relative of Bacillus subtilis, isolated from soil in Death Valley, California  

Microsoft Academic Search

Five Bacillus strains isolated from Death Valley soil were shown to belong to a previously unidentified species, for which we propose the name Bacillus vallismortis. The type strain is strain DV1-F-3 (= NRRL B-14890). On the basis of previously published restriction digestion data, B. vallismortis is most closely related to Bacillus subtilis. At this time B. vallismortis can be distinguished

Michael S. Roberts; Lawrence K. Nakamura; FREDERICK M. COHAN

1996-01-01

156

Surface emittance, temperature, and thermal inertia derived from Thermal Infrared Multispectral Scanner (TIMS) data for Death Valley, California  

Microsoft Academic Search

The NASA airborne Thermal Infrared Multispectral Scanner (TIMS) was flown over Death Valley, Califor- nia on both a daytime flight and a nighttime flight within a two-day period in July 1983. This Daedulus scanner has six channels in the thermal infrared, be- tween 8 and 12 pm. Calibrated digital spectral radiance data from these flights, along with Landsat Thematic Mapper

Anne B. Kahle

1987-01-01

157

STABLE ISOTOPE EVIDENCE OF HETEROGENEOUS FLUID INFILTRATION AT THE UBEHEBE PEAK CONTACT AUREOLE, DEATH VALLEY NATIONAL PARK, CALIFORNIA  

Microsoft Academic Search

Stable isotope ratios of carbon and oxygen are used to define quantitatively the effects of magmatic fluid infiltration in marbles contact meta- morphosed by the 173 Ma Ubehebe Peak quartz monzonite, Death Valley National Park, California. In previous studies of fluid infiltration, quantitative interpretation of aureole-wide isotopic data has been difficult due to small data sets. For this study, sampling

GREGORY T. ROSELLE; LUKAS P. BAUMGARTNER; JOHN W. VALLEY

158

Assessment of Computer-based Geologic Mapping of Rock Units in the LANDSAT-4 Scene of Northern Death Valley, California  

NASA Technical Reports Server (NTRS)

Results from a series of geologic classifications conducted on a thematic mapper subscene of the northern Death Valley, California are reported. Measurements of accuracy are made through comparison with the 1977 edition of the Death Valley geologic sheet. This employs a simplified map version which is registered by computer to the image data base, allowing a pixel by pixel match with the classified scene. The results show accuracy ranges from 36 to 79% depending on the type of classifier used and the statistical adjustments made to the data. Accuracy values in identifying geologic units were 2 to 3 times higher for those in the relatively flat valleys than for units in the rugged mountainous terrain. Improvements in accuracy will be sought by correcting for slope/aspect variations in mountainous terrain using topographic data recorded in Defense Mapping Agency (DMA) tapes. The above classification results will also be compared with ratio and principal component image classifications made from the same scene.

Short, N. M.

1984-01-01

159

Reconstructing late Pliocene to middle Pleistocene Death Valley lakes and river systems as a test of pupfish (Cyprinodontidae) dispersal hypotheses  

USGS Publications Warehouse

During glacial (pluvial) climatic periods, Death Valley is hypothesized to have episodically been the terminus for the Amargosa, Owens, and Mojave Rivers. Geological and biological studies have tended to support this hypothesis and a hydrological link that included the Colorado River, allowing dispersal of pupfish throughout southeastern California and western Nevada. Recent mitochondrial deoxyribonucleic acid (mtDNA) studies show a common pupfish (Cyprinodontidae) ancestry in this region with divergence beginning 3-2 Ma. We present tephrochronologic and paleomagnetic data in the context of testing the paleohydrologic connections with respect to the common collection point of the Amargosa, Owens, and Mojave Rivers in Death during successive time periods: (1) the late Pliocene to early Pleistocene (3-2 Ma), (2) early to middle Pleistocene (1.2-0.5 Ma), and (3) middle to late Pleistocene (<0.70.03 Ma; paleolakes Manly and Mojave). Using the 3.35 Ma Zabriskie Wash tuff and 3.28 Ma Nomlaki Tuff Member of the Tuscan and Tehama Formations, which are prominent marker beds in the region, we conclude that at 3-2 Ma, a narrow lake occupied the ancient Furnace Creek Basin and that Death Valley was not hydrologically connected with the Amargosa or Mojave Rivers. A paucity of data for Panamint Valley does not allow us to evaluate an Owens River connection to Death Valley ca. 3-2 Ma. Studies by others have shown that Death Valley was not hydrologically linked to the Amargosa, Owens, or Mojave Rivers from 1.2 to 0.5 Ma. We found no evidence that Lake Manly flooded back up the Mojave River to pluvial Lake Mojave between 0.18 and 0.12 Ma, although surface water flowed from the Amargosa and Owens Rivers to Death Valley at this time. There is also no evidence for a connection of the Owens, Amargosa, or Mojave Rivers to the Colorado River in the last 3-2 m.y. Therefore, the hypothesis that pupfish dispersed or were isolated in basins throughout southeastern California and western Nevada by such a connection is not supported. Beyond the biologically predicted time frame, however, sparse and disputed data suggest that a fluvial system connected Panamint (Owens River), Death, and Amargosa Valleys, which could account for the dispersal and isolation before 3 Ma. ?? 2008 The Geological Society of America.

Knott, J.R.; Machette, M.N.; Klinger, R.E.; Sarna-Wojcicki, A. M.; Liddicoat, J.C.; Tinsley, J. C., III; David, B.T.; Ebbs, V.M.

2008-01-01

160

Alluvial fan facies in Death Valley: Contrasts with fluvial gravels and implications for the interpretation of ancient fan'' gravels  

SciTech Connect

Sedimentary environments in Death Valley belong to three major groups: fans, washes, and playas. Fans in Death Valley include both diamicts and bedded gravels. Seven facies may be recognized. The diamicts include: (1) matrix-rich, coarse wackestones; (2) thin, matrix-rich, fine wackestones, that may show grading; (3) matrix-poor, coarse packstones, transitional to wackestones. The bedded facies include: (4) weakly bedded, poorly sorted packstones or grainstones, that show patchy imbrication, and cut-and-fill structures; (5) packed, imbricated cobble lenses, generally interbedded in facies 4; (6) distinctly bedded gravels, that are better bedded, finer and better sorted, and show better imbrication than facies 4, but still do not show clear separation of sand and gravel beds; (7) backfill cross-bedded gravels. Sand beds are not seen in fan deposits. Sand is present in eolian deposits of the playa, as plane-laminated, back-eddy deposits in Death Valley Wash, and as laminated or rippled sand in the Amargosa River, which drains into the south end of Death Valley. The most remarkable features of the fan and wash deposits are the very weak segregation of sand and gravel, and the absence of any lower flow-regime structures produced by ripples or dunes. During floods, the slope of fan and wash surfaces is steep enough to produce upper regime flows. Most fans in Death Valley itself are not strongly dominated by debris flow deposits (diamicts). Within a fan, facies vary little from proximal to distal regions, but may differ strongly from facies seen in adjacent fans.

Middleton, G.V. (McMaster Univ., Hamilton, Ontario (Canada). Dept. of Geology)

1993-03-01

161

Ground-water discharge determined from estimates of evapotranspiration, Death Valley regional flow system, Nevada and California  

USGS Publications Warehouse

The Death Valley regional flow system (DVRFS) is one of the larger ground-water flow systems in the southwestern United States and includes much of southern Nevada and the Death Valley region of eastern California. Centrally located within the ground-water flow system is the Nevada Test Site (NTS). The NTS, a large tract covering about 1,375 square miles, historically has been used for testing nuclear devices and currently is being studied as a potential repository for the long-term storage of high-level nuclear waste generated in the United States. The U.S. Department of Energy, as mandated by Federal and State regulators, is evaluating the risk associated with contaminants that have been or may be introduced into the subsurface as a consequence of any past or future activities at the NTS. Because subsurface contaminants can be transported away from the NTS by ground water, components of the ground-water budget are of great interest. One such component is regional ground-water discharge. Most of the ground water leaving the DVRFS is limited to local areas where geologic and hydrologic conditions force ground water upward toward the surface to discharge at springs and seeps. Available estimates of ground-water discharge are based primarily on early work done as part of regional reconnaissance studies. These early efforts covered large, geologically complex areas and often applied substantially different techniques to estimate ground-water discharge. This report describes the results of a study that provides more consistent, accurate, and scientifically defensible measures of regional ground-water losses from each of the major discharge areas of the DVRFS. Estimates of ground-water discharge presented in this report are based on a rigorous quantification of local evapotranspiration (ET). The study identifies areas of ongoing ground-water ET, delineates different ET areas based on similarities in vegetation and soil-moisture conditions, and determines an ET rate for each delineated area. Each area, referred to as an ET unit, generally consists of one or more assemblages of local phreatophytes or a unique moist soil environment. Ten ET units are identified throughout the DVRFS based on differences in spectral-reflectance characteristics. Spectral differences are determined from satellite imagery acquired June 21, 1989, and June 13, 1992. The units identified include areas of open playa, moist bare soils, sparse to dense vegetation, and open water. ET rates estimated for each ET unit range from a few tenths of a foot per year for open playa to nearly 9 feet per year for open water. Mean annual ET estimates are computed for each discharge area by summing estimates of annual ET from each ET unit within a discharge area. The estimate of annual ET from each ET unit is computed as the product of an ET unit's acreage and estimated ET rate. Estimates of mean annual ET range from 450 acre-feet in the Franklin Well area to 30,000 acre-feet in Sarcobatus Flat. Ground-water discharge is estimated as annual ET minus that part of ET attributed to local precipitation. Mean annual ground-water discharge estimates range from 350 acre-feet in the Franklin Well area to 18,000 acre-feet in Ash Meadows. Generally, these estimates are greater for the northern discharge areas (Sarcobatus Flat and Oasis Valley) and less for the southern discharge areas (Franklin Lake, Shoshone area, and Tecopa/ California Valley area) than those previously reported.

Laczniak, Randell J.; Smith, J. LaRue; Elliott, Peggy E.; DeMeo, Guy A.; Chatigny, Melissa A.; Roemer, Gaius J.

2001-01-01

162

Ground-water discharge determined from estimates of evapotranspiration, Death Valley regional flow system, Nevada and California  

SciTech Connect

The Death Valley regional flow system (DVRFS) is one of the larger ground-water flow systems in the southwestern United States and includes much of southern Nevada and the Death Valley region of eastern California. Centrally located within the ground-water flow system is the Nevada Test Site (NTS). The NTS, a large tract covering about 1,375 square miles, historically has been used for testing nuclear devices and currently is being studied as a potential repository for the long-term storage of high-level nuclear waste generated in the United States. The U.S. Department of Energy, as mandated by Federal and State regulators, is evaluating the risk associated with contaminants that have been or may be introduced into the subsurface as a consequence of any past or future activities at the NTS. Because subsurface contaminants can be transported away from the NTS by ground water, components of the ground-water budget are of great interest. One such component is regional ground-water discharge. Most of the ground water leaving the DVRFS is limited to local areas where geologic and hydrologic conditions force ground water upward toward the surface to discharge at springs and seeps. Available estimates of ground-water discharge are based primarily on early work done as part of regional reconnaissance studies. These early efforts covered large, geologically complex areas and often applied substantially different techniques to estimate ground-water discharge. This report describes the results of a study that provides more consistent, accurate, and scientifically defensible measures of regional ground-water losses from each of the major discharge areas of the DVRFS. Estimates of ground-water discharge presented in this report are based on a rigorous quantification of local evapotranspiration (ET). The study identifies areas of ongoing ground-water ET, delineates different ET areas based on similarities in vegetation and soil-moisture conditions, and determines an ET rate f or each delineated area. Each area, referred to as an ET unit, generally consists of one or more assemblages of local phreatophytes or a unique moist soil environment. Ten ET units are identified throughout the DVRFS based on differences in spectral-reflectance characteristics. Spectral differences are determined from satellite imagery acquired June 21, 1989 and June 13, 1992. The units identified include areas of open playa, moist bare soils, sparse to dense vegetation, and open water. ET rates estimated for each ET unit range from a few tenths of a foot per year for open playa to nearly 9 feet per year for open water. Mean annual ET estimates are computed for each discharge area by summing estimates of annual ET from each ET unit within a discharge area. The estimate of annual ET from each ET unit is computed as the product of an ET unit's acreage and estimated ET rate. Estimates of mean annual ET range from 450 acre-feet in the Franklin Well area to 30,000 acre-feet in Sarcobatus Flat. Ground-water discharge is estimated as annual ET minus that part of ET attributed to local precipitation. Mean annual ground-water discharge estimates range from 350 acre-feet in the Franklin Well area to 18,000 acre-feet in Ash Meadows. Generally, these estimates are greater for the northern discharge areas (Sarcobatus Flat and Oasis Valley) and less for the southern discharge areas (Franklin Lake, Shoshone area, and Tecopa/California Valley area) than those previously reported.

R.J. Laczniak; J. LaRue Smith; P.E. Elliott; G.A. DeMeo; M.A. Chatigny; G.J. Roemer

2001-12-31

163

An early Holocene glacial advance in the Macaulay River valley, central Southern Alps, New Zealand  

Microsoft Academic Search

A 10 km long valley glacier terminating between Lower Tindill and Tom Streams, in the Macaulay River valley, central Southern Alps, New Zealand, at 8690 120 years B.P. (NZ 6473A), is inferred from radiocarbon-dated deposits of till that were formerly thought to be of nonglacial origin. The glacial advance is one of three dated early Aranuian (post-14 000 years

M. J. McSaveney; Ian E. Whitehouse

1989-01-01

164

Paired, facing monoclines in the Sanpete-Sevier Valley area, central Utah  

USGS Publications Warehouse

Several major monoclines that trend northward through the Sanpete-Sevier Valley area of central Utah are paired and face one another. This pairing of monoclines may have occurred when near-horizontal sedimentary and volcanic strata subsided into voids created as salt was removed from a salt diapir concealed beneath valley fill. Removal was mostly by dissolution or extrusion during Neogene time. The paired monoclines, thus, are viewed as collapse features rather than as normal synclinal folds. -from Author

Witkind, I.J.

1992-01-01

165

Interpretive geologic cross sections for the Death Valley regional flow system and surrounding areas, Nevada and California  

SciTech Connect

This report presents a network of 28 geologic cross sections that portray subsurface geologic relations within the Death Valley regional ground-water system, a ground-water basin that encompasses a 3 degree x 3 degree area (approximately 70,000 square kilometers) in southern Nevada and eastern California. The cross sections transect that part of the southern Great Basin that includes Death Valley, the Nevada Test Site, and the potential high-level nuclear waste underground repository at Yucca Mountain. The specific geometric relationships portrayed on the cross sections are discussed in the context of four general sub-regions that have stratigraphic similarities and general consistency of structural style: (1) the Nevada Test Site vicinity; (2) the Spring Mountains, Pahrump Valley and Amargosa Desert region; (3) the Death Valley region; and (4) the area east of the Nevada Test Site. The subsurface geologic interpretations portrayed on the cross sections are based on an integration of existing geologic maps, measured stratigraphic sections, published cross sections, well data, and geophysical data and interpretations. The estimated top of pre-Cenozoic rocks in the cross sections is based on inversion of gravity data, but the deeper parts of the sections are based on geologic conceptual models and are more speculative.

D.S. Sweetkind; R.P. Dickerson; R.J. Blakely; P.D. Denning

2001-11-09

166

The Valley Fever Corridor Project The goals are twofold--to teach health care professionals in south-central  

E-print Network

The Valley Fever Corridor Project The goals are twofold--to teach health care professionals in south-central Arizona, especially in Maricopa County, essential information about Valley Fever Fever. This is a project of the Valley Fever Center for Excellence in the University of Arizona College

Arizona, University of

167

Style of deformation along the Death Valley-Furnace Creek fault zone and other faults in the southern Walker Lane, Nevada and California  

SciTech Connect

Quaternary normal and right-lateral faults and associated lineaments in the southern part of the Walker Lane are anomalous with respect to the north-striking normal faults in most of the central Great Basin. The authors identify and characterize many faults and lineaments that were previously unmapped, with the exception of faults in the Death Valley-Furnace Creek fault zone (DVFCFZ) and some faults in and near the Nevada Test Site. Faults and associated lineaments in deposits of late Cenozoic age are distinguished on the basis of age of most recent activity and orientation, and are grouped into two domains. One domain is characterized by northwest-striking faults and lineaments and associated north-striking en echelon structures within the DVFCFZ and the Pahrump fault zone; the other domain is characterized by north- to northeast-striking faults and linearments within a broad region east of the DVFCFZ that narrows southward toward the Pahrump fault zone. Preliminary observations of faults and linearments suggest dominantly right-oblique slip in the first domain and dominantly dip-slip in the second domain. The DVFCFZ is a regional right-lateral strike-slip system that shows changes in style of deformation along strike. Numerous normal faults at the northern end of the DVFCFZ in northern fish Lake Valley and the Volcanic Hills form an extensional right step that links the DVFCFZ with northwest-striking right-lateral faults of the northern part of the Walker Lane. South of this extensional step, the DVFCFZ trends southeast along strike-slip faults from central Fish Lake Valley to the latitude of Furnace Creek. From Furnace Creek, the fault zone apparently steps left to the Pahrump fault zone in the area of Ash Meadows where a complex zone of folds and faults of diverse orientation suggest local compression. This stepover coincides with east-northeast-striking faults that appear to be an extension of the left-lateral Rock Valley fault zone.

Noller, J.S. (William Lettis and Associates, Inc., Oakland, CA (United States)); Reheis, M.C. (Geological Survey, Denver, CO (United States))

1993-04-01

168

Geology of the central part of the James River Valley, Mason County, Texas  

E-print Network

?&V I'I. F3''% ~ ~ ~ ~ ~ * ~ ~ ~ ORDOVICIAN SXS~&, H F&LLZ;, "lRLRQRR GRC HF CEFOZOIC SXS; EP?S. ~ ~ ~ ~ ~ ;)UA'. %HART SXS FH ~ ~. . . ~ ~ ~ ~ ~ ~ ~ F Rt&C". . ?!RAL GEO~X ~ ~ C "'"'l?AL S". . A . . &N???. "T. . . . . . . o ~ ~ ~ o :. . A. I... VALLEY, RA~OR COURTY, TEXAS ABSTRACT The Central Part of the James River Valley is located ln south-central mason County, southwest of the town of' %aeon, Rock units of Uppex O'brien, Lower Ordovician, and Quaternary age sre found in the area, Ihe...

Dannemiller, George David

1957-01-01

169

Geologic Map of the Warm Spring Canyon Area, Death Valley National Park, Inyo County, California, With a Discussion of the Regional Significance of the Stratigraphy and Structure  

USGS Publications Warehouse

Warm Spring Canyon is located in the southeastern part of the Panamint Range in east-central California, 54 km south of Death Valley National Park headquarters at Furnace Creek Ranch. For the relatively small size of the area mapped (57 km2), an unusual variety of Proterozoic and Phanerozoic rocks is present. The outcrop distribution of these rocks largely resulted from movement on the east-west-striking, south-directed Butte Valley Thrust Fault of Jurassic age. The upper plate of the thrust fault comprises a basement of Paleoproterozoic schist and gneiss overlain by a thick sequence of Mesoproterozoic and Neoproterozoic rocks, the latter of which includes diamictite generally considered to be of glacial origin. The lower plate is composed of Devonian to Permian marine formations overlain by Jurassic volcanic and sedimentary rocks. Late Jurassic or Early Cretaceous plutons intrude rocks of the area, and one pluton intrudes the Butte Valley Thrust Fault. Low-angle detachment faults of presumed Tertiary age underlie large masses of Neoproterozoic dolomite in parts of the area. Movement on these faults predated emplacement of middle Miocene volcanic rocks in deep, east-striking paleovalleys. Excellent exposures of all the rocks and structural features in the area result from sparse vegetation in the dry desert climate and from deep erosion along Warm Spring Canyon and its tributaries.

Wrucke, Chester T.; Stone, Paul; Stevens, Calvin H.

2007-01-01

170

Potential hazards from floodflows in Grapevine Canyon, Death Valley National Monument, California and Nevada  

USGS Publications Warehouse

Grapevine Canyon is on the western slope of the Grapevine Mountains in the northern part of Death Valley National Monument , California and Nevada. Grapevine Canyon Road covers the entire width of the canyon floor in places and is a frequently traveled route to Scotty 's Castle in the canyon. The region is arid and subject to flash flooding because of infrequent but intense convective storms. When these storms occur, normally in the summer, the resulting floods may create a hazard to visitor safety and property. Historical data on rainfall and floodflow in Grapevine Canyon are sparse. Data from studies made for similar areas in the desert mountains of southern California provide the basis for estimating discharges and the corresponding frequency of floods in the study area. Results of this study indicate that high-velocity flows of water and debris , even at shallow depths, may scour and damage Grapevine Canyon Road. When discharge exceeds 4,900 cu ft/sec, expected at a recurrence interval of between 25 and 50 years, the Scotty 's Castle access road and bridge may be damaged and the parking lot partly inundated. A flood having a 100-year or greater recurrence interval probably would wash out the bridge and present a hazard to the stable and garage buildings but not to the castle buildings, whose foundations are higher than the predicted maximum flood level. (USGS)

Bowers, J.C.

1990-01-01

171

Sliding Rocks on Racetrack Playa, Death Valley National Park: First Observation of Rocks in Motion  

PubMed Central

The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved >60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, windowpane ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of ?45 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 25 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice. PMID:25162535

Lorenz, Ralph D.; Ray, Jib; Jackson, Brian

2014-01-01

172

Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.  

PubMed

The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice. PMID:25162535

Norris, Richard D; Norris, James M; Lorenz, Ralph D; Ray, Jib; Jackson, Brian

2014-01-01

173

An ostracode based paleolimnologic and paleohydrologic history of Death Valley: 200 to 0 ka  

USGS Publications Warehouse

Death Valley, a complex tectonic and hydrologic basin, was cored from its lowest surface elevation to a depth of 186 m. The sediments range from bedded primary halite to black muds. Continental ostracodes found in the black muds indicate that those sediments were deposited in a variety of hydrologic settings ranging from deep, relatively fresh water to shallow saline lakes to spring discharge supported wetlands. The alkaline-enriched, calcium-depleted paleolake waters indicate extrabasinal streamflow and basin-margin spring discharge. The alkaline-depleted, calcium-enriched paleowetland waters indicate intrabasinal spring discharge. During Marine Isotope Stage 6 (MIS 6, ca. 180-140 ka) the hydrologic settings were highly variable, implying that complex relations existed between climate and basin hydrology. Termination II (MIS 6 to MIS 5E) was a complex multicyclic sequence of paleoenvironments, implying that climates oscillated between high and low effective moisture. MIS 4 (ca. 73-61 ka) was a spring discharge supported wetland complex. During MIS 2 (ca. 20-12 ka) the hydrologic settings were variable, although they are not fully understood because some black muds deposited during that time were lost during coring. ?? 2005 Geological Society of America.

Forester, R.M.; Lowenstein, T.K.; Spencer, R.J.

2005-01-01

174

Height changes along selected lines through the Death Valley region, California and Nevada, 1905-1984  

USGS Publications Warehouse

Comparisons among repeated levelings along selected lines through the Death Valley region of California and adjacent parts of Nevada have disclosed surprisingly large vertical displacements. The vertical control data in this lightly populated area is sparse; moreover, as much as a third of the recovered data is so thoroughly contaminated by systematic error and survey blunders that no attempt was made to correct these data and they were simply discarded. In spite of these limitations, generally episodic, commonly large vertical displacements are disclosed along a number of lines. Displacements in excess of 0.4 m, with respect to our selected control point at Beatty, Nevada, and differential displacements of about 0.7 m apparently occurred during the earlier years of the 20th century and continued episodically through at least 1943. While this area contains abundant evidence of continuing tectonic activity through latest Quaternary time, it is virtually devoid of historic seismicity. We have detected no clear connection between the described vertical displacements and fault zones reportedly active during Holocene time, although we sense some association with several more broadly defined tectonic features.

Castle, Robert O.; Gilmore, Thomas D.; Walker, James P.; Castle, Susan A.

2005-01-01

175

Preliminary digital geologic maps of the Mariposa, Kingman, Trona, and Death Valley Sheets, California  

SciTech Connect

Parts of four 1:250,000-scale geologic maps by the California Department of Natural Resources, Division of Mines and Geology have been digitized for use in hydrogeologic characterization. These maps include the area of California between lat. 35{degree}N; Long. 115{degree}W and lat. 38{degree}N, long. 118{degree}W of the Kingman Sheet (Jennings, 1961), Trona Sheet (Jennings and others, 1962), Mariposa Sheet (Strand, 1967), and Death Valley Sheet (Streitz and Stinson, 1974). These digital maps are being released by the US Geological Survey in the ARC/INFO Version 6.1 Export format. The digitized data include geologic unit boundaries, fault traces, and identity of geologic units. The procedure outlined in US Geological Survey Circular 1054 (Soller and others, 1990) was sued during the map construction. The procedure involves transferring hard-copy data into digital format by scanning manuscript maps, manipulating the digital map data, and outputting the data. Most of the work was done using Environmental Systems Research Institute`s ARC/INFO software. The digital maps are available in ARC/INFO Rev. 6.1 Export format, from the USGS, Yucca Mountain Project, in Denver, Colorado.

D`Agnese, F.A.; Faunt, C.C.; Turner, A.K. [Geological Survey, Denver, CO (United States)

1995-10-01

176

Extraction of quantitative surface characteristics from AIRSAR data for Death Valley, California  

NASA Technical Reports Server (NTRS)

Polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data were collected for the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley, California, USA, in Sep. 1989. AIRSAR is a four-look, quad-polarization, three frequency instrument. It collects measurements at C-band (5.66 cm), L-band (23.98 cm), and P-band (68.13 cm), and has a GIFOV of 10 meters and a swath width of 12 kilometers. Because the radar measures at three wavelengths, different scales of surface roughness are measured. Also, dielectric constants can be calculated from the data. The AIRSAR data were calibrated using in-scene trihedral corner reflectors to remove cross-talk; and to calibrate the phase, amplitude, and co-channel gain imbalance. The calibration allows for the extraction of accurate values of rms surface roughness, dielectric constants, sigma(sub 0) backscatter, and polarization information. The radar data sets allow quantitative characterization of small scale surface structure of geologic units, providing information about the physical and chemical processes that control the surface morphology. Combining the quantitative information extracted from the radar data with other remotely sensed data sets allows discrimination, identification and mapping of geologic units that may be difficult to discern using conventional techniques.

Kierein-Young, K. S.; Kruse, F. A.

1992-01-01

177

Trace element geochemistry in water from selected springs in Death Valley National Park, California  

SciTech Connect

Concentrations of 40 trace elements and other constituents in ground water from springs in Death Valley National Park were measured to investigate whether trace element composition of the ground water can be related to the aquifer materials. Samples from these springs were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) for the trace elements and by ion chromatography (IC) for the major anions. A Principal Component Analysis was performed on the data set. Surprise and Scotty`s Springs formed one group; Texas, Nevares, and Travertine Springs formed another group; and Mesquite Springs did not group with any of the others. Scotty`s and Surprise Spring issued from volcanic rocks; Texas, Nevares, and Travertine discharge from carbonate rocks; and Mesquite Spring is located in alluvial basin-fill deposits. The first three components in each principal Component Analysis accounted for approximately 95% of the variance in the data set. The Principal Component Analysis suggests that ground water inherits its trace element composition from the rocks or aquifer material with which it has interacted and may be used for the purpose of identifying ground-water movement and source.

Kreamer, D.K.; Hodge, V.F.; Rabinowitz, I.; Johannesson, K.H.; Stetzenbach, K.J. [Univ. of Nevada, Las Vegas, NV (United States)

1996-01-01

178

Hydrostructural maps of the Death Valley regional flow system, Nevada and California  

SciTech Connect

The locations of principal faults and structural zones that may influence ground-water flow were compiled in support of a three-dimensional ground-water model for the Death Valley regional flow system, which covers 80,000 km2 in southwestern Nevada and southeastern California. Faults include Neogene extensional and strike-slip faults and pre-Tertiary thrust faults. Emphasis was given to characteristics of faults and deformed zones that may have a high potential for influencing hydraulic conductivity. These include: (1) faulting that results in the juxtaposition of stratigraphic units with contrasting hydrologic properties, which may cause ground-water discharge and other perturbations in the flow system; (2) special physical characteristics of the fault zones, such as brecciation and fracturing, that may cause specific parts of the zone to act either as conduits or as barriers to fluid flow; (3) the presence of a variety of lithologies whose physical and deformational characteristics m ay serve to impede or enhance flow in fault zones; (4) orientation of a fault with respect to the present-day stress field, possibly influencing hydraulic conductivity along the fault zone; and (5) faults that have been active in late Pleistocene or Holocene time and areas of contemporary seismicity, which may be associated with enhanced permeabilities.

Potter, C.J.; Sweetkind, D.S.; Dickerson, R.P.; Killgore, M.L.

2002-03-15

179

Diversity of Bacteria and Archaea in hypersaline sediment from Death Valley National Park, California  

PubMed Central

The objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain-specific primers, a region of the 16S rRNA gene was amplified using polymerase chain reaction (PCR), and the product was subsequently used to create a clone library. A total of 243 bacterial clones, 99 archaeal clones, and 209 bacterial isolates were examined. The 243 clones from Bacteria were affiliated with the following groups: the Bacilli (59 clones) and Clostridia (1) of the Firmicutes, Bacteroidetes (90), Proteobacteria (27), Cyanobacteria (18), Gemmatimonadetes (41), candidate division OP1 (5), Actinobacteria (1), and the Deinococcus-Thermus division (1). Within the class Bacilli, 46 of 59 clones were tentatively identified as 10 unclassified species. The majority of bacterial isolates (130 of 209) were more closely related to the Bacillus subtilisB. licheniformis clade than to any other recognized taxon, and an Ecotype Simulation analysis of B. subtilis relatives identified four previously unknown ecotypes. Several new genera were discovered within the Bacteroidetes (4) and the Gemmatimonadetes (2). Of the 99 archaeal clones, 94 were tentatively identified as belonging to 3 new genera within the Halobacteriaceae; other clones represented novel species within each of 4 established genera. PMID:22950020

Kim, Jong-Shik; Makama, Mfundi; Petito, Janine; Park, Nyun-Ho; Cohan, Frederick M; Dungan, Robert S

2012-01-01

180

Trail formation by ice-shoved "sailing stones" observed at Racetrack Playa, Death Valley National Park  

NASA Astrophysics Data System (ADS)

Trails in the usually-hard mud of Racetrack Playa in Death Valley National Park attest to the seemingly-improbable movement of massive rocks on an exceptionally flat surface. The movement of these rocks, previously described as "sliding stones", "playa scrapers", "sailing stones" etc., has been the subject of speculation for almost a century but is an exceptionally rare phenomenon and until now has not been directly observed. Here we report documentation of multiple rock movement and trail formation events in the winter of 2013-2014 by in situ observation, video, timelapse cameras, a dedicated meteorological station and GPS tracking of instrumented rocks. Movement involved dozens of rocks, forming fresh trails typically of 10s of meters length at speeds of ~5 cm s-1 and were caused by wind stress on a transient thin layer of floating ice. Fracture and local thinning of the ice decouples some rocks from the ice movement, such that only a subset of rocks move in a given event.

Lorenz, R. D.; Norris, J. M.; Jackson, B. K.; Norris, R. D.; Chadbourne, J. W.; Ray, J.

2014-08-01

181

Structural evolution of the virgin spring phase of the amargosa chaos, Death Valley, California, USA  

NASA Astrophysics Data System (ADS)

The Amargosa Chaos and Fault of Death Valley are complex features that play important roles in various tectonic models. Some recent models claim the fault is a regional detachment accommodating 80 km of NW-directed transport that produced the Chaos in its hangingwall. I offer an alternative interpretation: the chaos is a product of multiphase deformation that likely spanned the late Mesozoic and Cenozoic. The Amargosa Fault represents just one of six deformation events. The accompanying map (supplemental file) shows the cross-cutting relationships among fault populations: (D1) 25% north-northwest directed shortening across an imbricate thrust and tight fold system; (D2) E-SE extension on five normal faults; (D3) extension-related folding, which folded the D2 faults; (D4) normal-oblique slip on the Amargosa Fault; (D5) E-W extension on domino faults; (D6) extension on the Black Mountains Frontal Fault. The D2 faults, not the Amargosa, created the enigmatic attenuation observed in the Chaos.

Castonguay, Samuel Robert

182

Case Studies of Water Vapor and Surface Liquid Water from AVIRIS Data Measured Over Denver, CO and Death Valley, CA  

NASA Technical Reports Server (NTRS)

High spatial resolution column atmospheric water vapor amounts and equivalent liquid water thicknesses of surface targets are retrieved from spectral data collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). The retrievals are made using a nonlinear least squares curve fitting technique. Two case studies from AVIRIS data acquired over Denver-Platteville area, Colorado and over Death Valley, California are presented. The column water vapor values derived from AVIRIS data over the Denver-Platteville area are compared with those obtained from radiosondes, ground level upward-looking microwave radiometers, and geostationary satellite measurements. The column water vapor image shows spatial variation patterns related to the passage of a weather front system. The column water vapor amounts derived from AVIRIS data over Death Valley decrease with increasing surface elevation. The derived liquid water image clearly shows surface drainage patterns.

Gao, B.-C.; Kierein-Young, K. S.; Goetz, A. F. H.; Westwater, E. R.; Stankov, B. B.; Birkenheuer, D.

1991-01-01

183

Thematic Mapper and field investigations at the intersection of the Death Valley and Garlock fault zones, California  

NASA Technical Reports Server (NTRS)

Analysis of processed images and detailed field investigations have provided significant information concerning the late-Pliocene and Quaternary evolution of the intersection of the Garlock and Death Valley fault zones. The imagery was used to determine patterns of sedimentation and age relationships on alluvial fans and to determine the geometry, styles of deformation, and relative ages of movements on major and minor faults in the study area. The field investigation often confirmed the inferences drawn from the images and provided additional tectonic and geomorphologic data about the Quaternary deformation of the region. All the data gathered in the course of this project support the contention that the Garlock fault zone terminates in the Avawatz Mountains and that the Death Valley fault zone continues south of the intersection for at least 50 km, forming the eastern boundary of the Mojave province.

Brady, Roland H., III; Cregan, Alan; Clayton, Jeff; Troxel, Bennie W.; Verosub, Kenneth L.; Abrams, Michael

1989-01-01

184

Geologic application of thermal inertia imaging using HCMM data. [Death Valley and Pisgah Crater, California and Goldfield, Nevada  

NASA Technical Reports Server (NTRS)

During the July to September 1980 quarter the final tapes were received completing the order and preliminary processing was done. Thermal Inertia images for each of the three test sites, Death Valley and Pisgah Crater, California and Goldfield, Nevada were created using registered HCMM day/night pairs and the JPL model. A comprehensive study and analysis of the geologic application of all acquired HCMM data is in progress.

Paley, H. N.; Kahle, A. B. (principal investigators)

1980-01-01

185

Sedimentology and progressive tectonic unconformities of the sheetflood-dominated Hell's Gate alluvial fan, Death Valley, California  

Microsoft Academic Search

The Hell's Gate alluvial fan of northern Death Valley has an area of 49.5km2, a radius of 11.8km, and a smooth 53 sloping surface interrupted by shallow (<0.5m), radially aligned gullies 14m wide. Facies analysis of 114m high exposures at 45 sites reveals that the fan is built almost entirely by water-flow processes. Two facies deposited by sheetflooding dominate the

T. C. Blair

2000-01-01

186

along the northern Death Valley fault zone: Implications for transient strain in the eastern California shear zone  

Microsoft Academic Search

(1) The northern Death Valley fault zone (NDVFZ) has long been recognized as a major right-lateral strike-slip fault in the eastern California shear zone (ECSZ). However, its geologic slip rate has been difficult to determine. Using high-resolution digital topographic imagery and terrestrial cosmogenic nuclide dating, we present the first geochronologically determined slip rate for the NDVFZ. Our study focuses on

Kurt L. Frankel; Katherine S. Brantley; James F. Dolan; Robert C. Finkel; Ralph E. Klinger; Jeffrey R. Knott; Michael N. Machette; Lewis A. Owen; Fred M. Phillips; Janet L. Slate; Brian P. Wernicke

187

Photoinhibition of the CAM succulent Opuntia basilaris growing in Death Valley: evidence from 77K fluorescence and quantum yield  

Microsoft Academic Search

Diurnal measurements of low temperature (77K) fluorescence at 690 nm (PS II) from north, south, east, and west facing cladode surfaces of Opuntia basilaris in Death Valley, California were made on six occasions during 1985. The absolute levels of Fo(instantaneous fluorescence) and Fm(maximum fluorescence), as well as the ratio Fv\\/Fm(variable fluorescence, Fm-Fo, over maximum fluorescence), were greater in the north

W. W. Adams III; S. D. Smith; C. B. Osmond

1987-01-01

188

Death Valley Lower Carbonate Aquifer Monitoring Program Wells Down gradient of the Proposed Yucca Mountain Nuclear Waste Repository  

SciTech Connect

Inyo County has participated in oversight activities associated with the Yucca Mountain Nuclear Waste Repository since 1987. The overall goal of these studies are the evaluation of far-field issues related to potential transport, by ground water, or radionuclides into Inyo County, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. In addition to the potential of radionuclide transport through the LCA, Czarnecki (1997), with the US Geological Survey, research indicate potential radionuclide transport through the shallower Tertiary-age aquifer materials with ultimate discharge into the Franklin Lake Playa in Inyo County. The specific purpose of this Cooperative Agreement drilling program was to acquire geological, subsurface geology, and hydrologic data to: (1) establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin; (2) characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and (3) Evaluation the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA.

Inyo County

2006-07-26

189

Historical Abundance and Decline of Chinook Salmon in the Central Valley Region of California  

Microsoft Academic Search

The Central Valley drainage of California formerly produced immense numbers of chinook salmon Oncorhynchus tshawytscha. Four seasonal runs occur in this systemfall, late-fall, winter, and spring runs. Differences in life history timing and spatial distribution enabled the four runs to use the drainage to the fullest possible extent and once made it one of the richest regions in the world

Ronald M. Yoshiyama; Frank W. Fisher; Peter B. Moyle

1998-01-01

190

Aeolian Geomorphic Response to Climate Change: An Example from the Estancia Valley, Central New Mexico, USA  

Microsoft Academic Search

Three generations of Holocene aeolian activity are preserved along the axis of the Estancia Valley, central New Mexico, USA. The transition from large dome dunes to parabolic dunes to loess reflects differences in sedimentation and environments, controlled by climate change. The aeolian landscape developed on the final lacustrine plain of a complex series of freshwater pluvial lakes that occupied the

N. R. CATTO; F. W. BACHHUBER

191

Development of Biological and Cultural Control of Olive Fruit Fly in the Central Valley of California  

Technology Transfer Automated Retrieval System (TEKTRAN)

The eastern side of the Central Valley of California where olives are grown for canning was surveyed for olive fruit fly, Bactrocera oleae (Rossi), infestations. The pest was found for the first time in unusually high numbers in Merced. The a parasitic wasp, Psyttalia humilis (Silvestri), was import...

192

COMMUNITY AND EDAPHIC ANALYSIS OF MIXED OAK FORESTS IN RIDGE AND VALLEY PROVINCE OF CENTRAL PENNSYLVANIA  

Microsoft Academic Search

Forty-two relatively undisturbed mixed oak stands on nine different physiographic units in the Ridge and Valley Province of central Pennsylvania were surveyed to investigate the ecological status of oak species in the region. Quercus species were primarily restricted to the canopy, with the exception of Quercus ilicifolia Wangenh. (a shrub). The most species rich forest stands were located along an

Gregory J. Nowacki; Marc D. Abrams

193

Drought resilience of the California Central Valley surface-groundwater-conveyance system  

Microsoft Academic Search

A series of drought simulations were performed for the California Central Valley using computer applications developed by the California Department of Water Resources and historical datasets representing a range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping patterns, and water demand were held fixed at the 2003 level and water

N. L. Miller; L. L. Dale; C. Brush; S. Vicuna; T. N. Kadir; E. C. Dogrul; F. I. Chung

2009-01-01

194

Barriers to Coverage of Transborder Environmental Issues in the Ferghana Valley of Central Asia  

ERIC Educational Resources Information Center

Three former Soviet republics occupy Central Asia's Ferghana Valley, a region of serious transborder environmental problems, especially ones that involve water and energy. Most news organizations in Kyrgyzstan, Tajikistan, and Uzbekistan provide little in-depth coverage of these issues. Journalists in one country usually do not seek news

Freedman, Eric

2014-01-01

195

Stable Ca Isotopes in Tamarix aphylla Tree Rings, Death Valley, California  

NASA Astrophysics Data System (ADS)

As a dune stabilizer and windbreak, Tamarix aphylla is an exotic perennial and evergreen tree in Death Valley. Its tap roots can reach down to 30 m depth and sub-superficial side roots may reach 50 m horizontally. The species can store large amounts of water in its roots and undergoes high evapotranspiration. Since Tamarix aphylla is a perennial tree growing in desert environments and its roots reach deep to the water table, it could be a proxy for desert ecological and hydrologic systems through time. We measured Ca isotopes in the soluble fraction of 8 tree ring samples from a 50-year-old specimen growing on an alluvial fan in Death Valley near Furnace Creek. Previous studies (Yang et al, GCA 60, 1996) indicate that this tree's rings contain high sulfur concentrations (4-6% expressed as sulfate) with chemical composition of CaSO4 (0.15-0.62 H2O). The ?34S values of soluble sulfate increase from +13.5 to +18 permil VCDT from the core to the bark, which are interpreted as reflecting deeper sulfate sources as the tree grew. The ?13C variations of the tree-ring cellulose (-27.6 to -24.0 permil VPDB) reflect changes in the local precipitation and show that Tamarix aphylla undergoes C3 photosynthesis. The ?44Ca for the soluble sulfate Ca through the tree-ring section, which covers a time period from 1945 to 1993, have an average value -2.52 permil (-3.4 permil relative to seawater). Only small variations are observed, from -2.69 to -2.28; the highest value (for 1990) occurs near the end of an extended drought. These are the first measurements of tree rings, but the low ?44Ca values are consistent with previous measurements of beech roots and stems from a temperate forest (Page et al., Biogeochem. 88, 2008). In our case, the tree has only one Ca source, which is expected to be isotopically uniform and similar to both local rainfall and limestones (?44Ca ~ -0.6 permil), and with the minimal vegetation and extensive deep root system it is unlikely that there is a significant depletion of soil Ca due to plant uptake. Thus the Ca isotopic fractionation between trunk and source (?Ca = -2 permil) is clearly defined by the data. By analogy to the results of Page et al., the Ca fractionation between root and source may be larger (?Ca ~ -3 permil). This biological Ca isotope fractionation is no doubt due to transport processes during root uptake of Ca, but the magnitude is significantly larger than that observed for inorganic processes such as mineral precipitation or aqueous diffusion. The slight increase in ?44Ca in drought conditions suggests that when the tree is stressed there may be less Ca isotope fractionation, either because the Ca is held more tightly in small pores in the soil, or because the available Ca pool shrinks such that the soil Ca starts to shift to more positive ?44Ca values due to depletion of light Ca by the plant. The slowly accumulating database on Ca isotopes in plants continues to suggest that systematic Ca isotope studies may be fruitful for understanding cation transport in plants, and soil ecological conditions in general.

Yang, W.; Depaolo, D. J.; Ingram, B. L.; Owens, T. L.

2008-12-01

196

Three-dimensional deformation and stress models of the Death Valley and San Andreas Fault Zones  

NASA Astrophysics Data System (ADS)

Crustal deformation studies of tectonic motions have been the topic of many scientific investigations, as they can provide critical information about how tectonic structures shape and deform the Earth. While crustal deformation studies using observational data alone can provide a great deal of information about how the Earth is presently deforming, it is standard practice to implement mathematical and physics-based models to investigate the underlying causes of deformation in the crust. These models, constrained by geological, geodetic and seismic data, have successfully contributed key constraints of ongoing deformation processes and have provided predictions of past and future tectonic behavior of the Earth. One of the most popular regions of study on Earth is the San Andreas Fault System (SAFS), as it provides an ideal environment for investigating the deformation caused by a major continental transform boundary. Furthermore, the Death Valley Fault Zone (DVFZ) is an ideal area to study large-scale crustal deformation due to its well-exposed features related to progressive extensional deformation. This dissertation presents new information about the deformation, stress accumulation rates, and strain rates taking place in the DVFZ and SAFS using three-dimensional (3-D) crustal deformation models. Chapter 1 provides the background and motivation of the modeling work applied to both fault systems. Chapter 2 provides the results obtained from applying a 3-D semi-analytic viscoelastic model constrained by GPS measurements to explore the kinematics and stress accumulation in the DVFZ. Chapter 3 analyzes the influence of intrusions on the motion and deformation of the DVFZ through a finite difference modeling approach. Chapter 4 explores the strain rate distribution within the SAFS, assuming a dipping fault geometry for its southern segments, utilizing a modified 3-D semi-analytic viscoelastic model. Lastly, Chapter 5 gives a description of the future work that may be followed based on the results obtained from this dissertation work.

Del Pardo, Cecilia

197

Are the benches at Mormon Point, Death Valley, California, USA, scarps or strandlines?  

USGS Publications Warehouse

The benches and risers at Mormon Point, Death Valley, USA, have long been interpreted as strandlines cut by still-stands of pluvial lakes correlative with oxygen isotope stage (OIS) 5e/6 (120,000-186,000 yr B.P.) and OIS-2 (10,000-35,000 yr B.P.). This study presents geologic mapping and geomorphic analyses (Gilbert's criteria, longitudinal profiles), which indicate that only the highest bench at Mormon Point (~90 m above mean sea level (msl)) is a lake strandline. The other prominent benches on the north-descending slope immediately below this strandline are interpreted as fault scarps offsetting a lacustrine abrasion platform. The faults offsetting the abrasion platform most likely join downward into and slip sympathetically with the Mormon Point turtleback fault, implying late Quaternary slip on this low-angle normal fault. Our geomorphic reinterpretation implies that the OIS-5e/6 lake receded rapidly enough not to cut strandlines and was ~90 m deep. Consistent with independent core studies of the salt pan, no evidence of OIS-2 lake strandlines was found at Mormon Point, which indicates that the maximum elevation of the OIS-2 lake surface was -30 m msl. Thus, as measured by pluvial lake depth, the OIS-2 effective precipitation was significantly less than during OIS-5e/6, a finding that is more consistent with other studies in the region. The changed geomorphic context indicates that previous surface exposure dates on fault scarps and benches at Mormon Point are uninterpretable with respect to lake history. ?? 2002 University of Washington.

Knott, J.R.; Tinsley, J. C., III; Wells, S.G.

2002-01-01

198

Are the Benches at Mormon Point, Death Valley, California, USA, Scarps or Strandlines?  

NASA Astrophysics Data System (ADS)

The benches and risers at Mormon Point, Death Valley, USA, have long been interpreted as strandlines cut by still-stands of pluvial lakes correlative with oxygen isotope stage (OIS) 5e/6 (120,000-186,000 yr B.P.) and OIS-2 (10,000-35,000 yr B.P.). This study presents geologic mapping and geomorphic analyses (Gilbert's criteria, longitudinal profiles), which indicate that only the highest bench at Mormon Point (90 m above mean sea level (msl)) is a lake strandline. The other prominent benches on the north-descending slope immediately below this strandline are interpreted as fault scarps offsetting a lacustrine abrasion platform. The faults offsetting the abrasion platform most likely join downward into and slip sympathetically with the Mormon Point turtleback fault, implying late Quaternary slip on this low-angle normal fault. Our geomorphic reinterpretation implies that the OIS-5e/6 lake receded rapidly enough not to cut strandlines and was 90 m deep. Consistent with independent core studies of the salt pan, no evidence of OIS-2 lake strandlines was found at Mormon Point, which indicates that the maximum elevation of the OIS-2 lake surface was -30 m msl. Thus, as measured by pluvial lake depth, the OIS-2 effective precipitation was significantly less than during OIS-5e/6, a finding that is more consistent with other studies in the region. The changed geomorphic context indicates that previous surface exposure dates on fault scarps and benches at Mormon Point are uninterpretable with respect to lake history.

Knott, Jeffrey R.; Tinsley, John C.; Wells, Stephen G.

2002-11-01

199

Preliminary Characterization of a Microbial Community of Rock Varnish from Death Valley, California  

NASA Technical Reports Server (NTRS)

Rock varnish (also referred to as desert varnish in the literature because it is particularly noticeable in desert environments) is a dark, thin (typically 50-500 m thick), layered veneer composed of clay minerals cemented together by oxides and hydroxides of manganese and iron. Some scientists suggest that varnish may provide a historical record of environmental processes such as global warming and long-term climate change. However, despite more than 30 years of study using modern microanalytical and microbial culturing techniques, the nucleation and growth mechanisms of rock varnish remain a mystery. Rock varnish is of interest to the Mars science community because a varnish-like sheen has been reported on the rocks at the Viking Lander sites. It therefore important for us to understand the formation mechanisms of terrestrial varnish abiotic, biotic, or a combination of the two -- as this understanding may give us clues concerning the chemical and physical processes occurring on the surface of Mars. It is strongly believed by some in the biogeochemistry community that microbes have a role in forming rock varnish, and iron- and manganese-oxidation by microbes isolated from varnish has been extensively investigated. Only two of these studies have investigated the microbial genetics of varnish. These studies examined the morphological, physiological and molecular characteristics of microbes that had previously been cultured from various rock varnishes and identified the cultivars using 16S rDNA sequencing techniques. However, it is well known that most of organisms existing in nature are refractory to cultivation, so many important organisms would have been missed. The currently described work investigates the genetics of rock varnish microbial community from a site in the Whipple Mtns., south of Death Valley, CA, near Parker, Arizona. We employed both cultural and molecular techniques to characterize the microorganisms found within the varnish and surrounding soil with the objectives of (a) identifying microorganisms potentially involved in varnish formation, and (b) discovering microorganisms that simply use the varnish as an extreme habitat.

Kuhlman, K. R.; LaDuc, M. T.; Kuhlman, G. M.; Anderson, R. C.; Newcombe, D. A.; Fusco, W.; Steucker, T.; Allenbach, L.; Ball, C.; Crawford, R. L.

2003-01-01

200

Natural Cardiac Deaths in Central Indiana Chelsea Dodge  

E-print Network

disease (571) and congestive heart failure (189). Hypertrophic cardiomyopathy (89), cardiomegaly (16. Within cardiovascular disease there are many subtypes that cause death including hypertensive heart disease, atherosclerosis, coronary heart disease (CAD), myocardial infarction (MI), dilated cardiomyopathy

Zhou, Yaoqi

201

Wildlife Diversity in Valley-Foothill Riparian Habitat: North Central vs. Central Coast California1  

E-print Network

study areas: Dye Creek, Tehama County, and Avenales Ranch, San Luis Obispo County, California at the eastern edge of the Sacramento Valley in Tehama County on the 18,180-ha Dye Creek Ranch, about 25 km

Standiford, Richard B.

202

JC Virus Induces Nonapoptotic Cell Death of Human Central Nervous System Progenitor Cell-Derived Astrocytes  

Microsoft Academic Search

JC virus (JCV), a human neurotropic polyomavirus, demonstrates a selective glial cell tropism that causes cell death through lytic infection. Whether these cells die via apoptosis or necrosis following infection with JCV remains unclear. To investigate the mechanism of virus-induced cell death, we used a human central nervous system progenitor-derived astrocyte cell culture model developed in our laboratory. Using in

Pankaj Seth; Frank Diaz; Jung-Hwa Tao-Cheng; Eugene O. Major

2004-01-01

203

Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley  

PubMed Central

Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ?50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ?7 higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley. PMID:22645352

Scanlon, Bridget R.; Faunt, Claudia C.; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

2012-01-01

204

Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley  

USGS Publications Warehouse

Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ~50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km3 of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ~7 higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km3, occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km3 shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley.

Scanlon, Bridget R.; Faunt, Claudia C.; Longuevergne, Laurent; Reedy, Robert C.; Alley, William M.; McGuire, Virginia L.; McMahon, Peter B.

2012-01-01

205

Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley.  

PubMed

Aquifer overexploitation could significantly impact crop production in the United States because 60% of irrigation relies on groundwater. Groundwater depletion in the irrigated High Plains and California Central Valley accounts for ~50% of groundwater depletion in the United States since 1900. A newly developed High Plains recharge map shows that high recharge in the northern High Plains results in sustainable pumpage, whereas lower recharge in the central and southern High Plains has resulted in focused depletion of 330 km(3) of fossil groundwater, mostly recharged during the past 13,000 y. Depletion is highly localized with about a third of depletion occurring in 4% of the High Plains land area. Extrapolation of the current depletion rate suggests that 35% of the southern High Plains will be unable to support irrigation within the next 30 y. Reducing irrigation withdrawals could extend the lifespan of the aquifer but would not result in sustainable management of this fossil groundwater. The Central Valley is a more dynamic, engineered system, with north/south diversions of surface water since the 1950s contributing to ~7 higher recharge. However, these diversions are regulated because of impacts on endangered species. A newly developed Central Valley Hydrologic Model shows that groundwater depletion since the 1960s, totaling 80 km(3), occurs mostly in the south (Tulare Basin) and primarily during droughts. Increasing water storage through artificial recharge of excess surface water in aquifers by up to 3 km(3) shows promise for coping with droughts and improving sustainability of groundwater resources in the Central Valley. PMID:22645352

Scanlon, Bridget R; Faunt, Claudia C; Longuevergne, Laurent; Reedy, Robert C; Alley, William M; McGuire, Virginia L; McMahon, Peter B

2012-06-12

206

Hydrogeologic framework of Antelope Valley and Bedell Flat, Washoe County, west-central Nevada  

USGS Publications Warehouse

Description of the hydrogeologic framework of Antelope Valley and Bedell Flat in west-central Nevada adds to the general knowledge of regional ground-water flow north of the Reno-Sparks metropolitan area. The hydrogeologic framework is defined by the rocks and deposits that transmit ground water or impede its movement and by the combined thickness of Cenozoic deposits. When data are lacking about the subsurface geology of an area, geophysical methods can be used to provide additional information. In this study, gravimetric and seismic-refraction methods were used to infer the form of structural features and to estimate the thickness of Cenozoic deposits in each of the two valleys. In Antelope Valley, the thickness of these deposits probably does not exceed about 300 feet, suggesting that ground-water storage in the basin-fill aquifer is limited. Beneath Bedell Flat is an elongated, northeast-trending structural depression in the pre-Cenozoic basement; the maximum thickness of Cenozoic deposits is about 2,500 feet beneath the south-central part of the valley. Shallow ground water in the northwest corner of Bedell Flat may be a result of decreasing depth to the pre-Cenozoic basement.

Berger, D.L.; Ponce, D.A.; Ross, W.C.

2001-01-01

207

Evaluation of multi-scale hyperspectral reflectance and emittance image data for remote mineral mapping in northeastern Death Valley National Park, California and Oasis Valley, Nevada  

NASA Astrophysics Data System (ADS)

This dissertation focuses upon the analyses of hyperspectral reflectance and thermal emission image data to remotely detect and map surficial mineralogy in an arid environment in southern Nevada and southeastern California. It includes four manuscripts prepared for submission to peer-reviewed journals, which are presented as single chapters. The research involves the use of longwave-infrared (LWIR) hyper- and multi-spectral measurements made from ground, aerial, and spaceborne perspectives of sedimentary and meta-sedimentary geologic units in northeastern Death Valley National Park, California and both shortwave-infrared (SWIR) and LWIR hyperspectral measurements in an area of diverse Paleozoic and Tertiary geology in Oasis Valley, Nevada. In Chapter 1, a brief overview of the dissertation is provided, including background on reflected and thermal-infrared mineral spectroscopy; remote sensing; the impacts of spatial and spectral resolution upon the ability to detect, identify, and map minerals using remote sensing image data; and the use of combined reflectance and emittance image data to better map minerals. In Chapter 2, ground-based SEBASS LWIR hyperspectral image data is analyzed in order to determine the utility of very high resolution remotely-sensed emittance measurements to delineate late-Proterozoic and Paleozoic sedimentary lithologies of an outcrop at Hell's Gate, Death Valley. In Chapter 3, airborne SEBASS image data over Boundary Canyon are analyzed in conjunction with moderate-scale geologic maps and laboratory measurements to map minerals associated with sedimentary and meta-sedimentary rocks and important in recognizing a detachment fault structure, as well as metamorphic facies. In Chapter 4, ground-based and aerial SEBASS, aerial MASTER, and spaceborne ASTER emittance measurements are compared over two study sites to determine what repercussions viewing perspective and spatial, spectral, and radiometric resolutions have upon remote identification and mapping of minerals associated with the Boundary Canyon detachment fault. In Chapter 5, a comparison of reflectance and emittance hyperspectral measurements made over Oasis Valley is used to determine whether certain minerals are optimally detected, identified, and mapped within a certain wavelength range. In Chapter 6, the presented research is summarized, repercussions of the results are analyzed, and future research possibilities are suggested. The research was successful in presenting: (1) new uses of imaging spectrometer data, (2) identifying mineralogic indicators of detachment faulting in the Boundary Canyon study area, (3) scale-based limitations upon detection of these mineral components associated with detachment faulting, and (4) limitations upon identifying particular minerals in specific wavelength segments, thereby constraining expectations of future VNIR/SWIR and LWIR image data mineral mapping surveys.

Aslett, Zan

208

Pleistocene-Holocene transition in the central Mississippi River valley  

NASA Astrophysics Data System (ADS)

Within the northern Mississippi embayment the ancestral Mississippi River flowed south through the Western Lowlands and the ancestral Ohio River flowed through the Eastern Lowlands for most of the Pleistocene. Previous investigators have mapped and dated the terraces of their respective braid belts. This current research investigates the three-dimensional aspect of the Quaternary alluvium north of Memphis, Tennessee, through the interpretation of 3374 geologic well logs that are 91.4 m (300 ft) deep. The braid belts are capped by a thin silt/clay horizon (Pleistocene loess) that overlies gravelly sand, which in turn overlies sandy gravel. The base of the Pleistocene alluvium beneath the Ash Hill (27.3-24.6 ka), Melville Ridge (41.6-34.5 ka), and Dudley (63.5-50.1 ka) terraces of the Western Lowland slope southerly by 0.275 m/km and all have an average basal elevation of 38 m. Near Beedeville, Arkansas, the bases of these terraces descend 20 m across a northeast-striking down-to-the-southeast fault that coincides with the western margin of the Cambrian Reelfoot rift. The maximum depth of flow (lowest elevation of base of alluvium) occurred in the Eastern Lowlands and appears to have been the downstream continuation of the ancestral Ohio River Cache valley course in southern Illinois. In traversing from west to east in the Eastern Lowlands, the Sikeston braid belt (19.7-17.8 ka) has a basal elevation averaging 7 m, the Kennett braid belt (16.1-14.4 ka) averages 13 m, the Morehouse (12 ka) braid belt averages 24 m, and the Holocene (? 10 ka) Mississippi River floodplain has the highest average basal elevation at 37 m. Along this easterly traverse the base of the Quaternary alluvium rises and the age of alluvium decreases. The eastward thinning of the floodplain alluvium in the Eastern Lowlands appears to be caused by decreasing Mississippi River discharge as it transitioned from the Wisconsinan glacial maximum to the Holocene. The base of the Holocene Mississippi River floodplain averages 23 m higher in elevation than the Pleistocene floodplain bases in the Eastern Lowlands. This high suballuvial surface (platform) is bound by the tectonically uplifted Joiner ridge, Blytheville arch, Charleston uplift, and Bluff Line fault. The spatial relationship and similar histories of the platform and bounding structures suggest that Quaternary erosion and tectonics are related.

Van Arsdale, Roy B.; Cupples, William B.; Csontos, Ryan M.

2014-06-01

209

Simulation of recharge for the Death Valley regional groundwater flow system using an integrated hydrologic model  

NASA Astrophysics Data System (ADS)

A proof-of-concept study was conducted using the integrated hydrologic model, GSFLOW, to simulate spatially and temporally distributed recharge for the Death Valley regional groundwater flow system (DVRFS). GSFLOW is an integrated groundwater - surface water flow model that combines two modeling applications: the Precipitation-Runoff-Modeling-System (PRMS) and MODFLOW. Previous methods used to estimate recharge for the DVRFS include empirical models based on precipitation, applications of the chloride mass-balance method, and applications of a precipitation-runoff model, INFIL, which used a daily time step to simulate recharge as net infiltration through the root zone. The GSFLOW model offers several potential advantages compared to the previous methods including (1) the ability to simulate complex flow through a thick unsaturated zone (UZ), allowing for the dampening and time delay of recharge relative to the infiltration signal at the top of the UZ and also allowing for the redistribution of flow within the UZ, as enabled by the MODFLOW-NWT and UZF capabilities, (2) the simulation of rejected recharge in response to the dynamics of groundwater discharge and low permeability zones in the UZ, (3) a more explicit representation of streamflow and recharge processes in the mostly ephemeral stream channels that characterize the DVRFS, and (4) the ability to simulate complex flow paths for runoff occurring as both overland flow and shallow subsurface flow (interflow) in the soil zone using a network of cascades connecting hydrologic response units (HRUs). Simulations were done using a daily time step for water years 1980-2010. Preliminary estimates of recharge using GSFLOW indicate that the distribution of recharge is highly variable both spatially and temporally due to variability in precipitation, snowmelt, evapotranspiration, runoff, and the permeability of bedrock and alluvium underlying the root zone. Results averaged over the areas of subbasins were similar to results obtained from previous studies. However, estimates of recharge on the local scale of the HRUs indicate significant (greater than 100 percent) differences at some locations compared to results obtained using INFIL due to differences in (1) the geometry and scale of HRUs, (2) the layout of the cascading flow network and the location of stream channels, (3) the representation of the physical characteristics of the root zone, and (4) model processes controlling the simulation of evapotranspiration and the movement of water through the root zone.

Hevesi, J. A.; Regan, R. S.; Hill, M. C.; Heywood, C.; Kohn, M. S.

2012-12-01

210

Spatially distributed pesticide exposure assessment in the Central Valley, California, USA.  

PubMed

Field runoff is an important transport mechanism by which pesticides move into the hydrologic environment of intensive agricultural regions such as California's Central Valley. This study presents a spatially explicit modeling approach to extend Pesticide Root Zone Model (PRZM), a field-scale pesticide transport model, into basin level. The approach was applied to simulate chlorpyrifos use in the Central Valley during 2003-2007. The average value of loading as percent of use (LAPU) is 0.031%. Results of this study provide strong evidence that surface runoff generation and pesticide application timing are the two influencing factors on the spatial and temporal variability of chlorpyrifos sources from agricultural fields. This is one of the first studies in coupling GIS and field-scale models and providing simulations for the dynamics of pesticides over an agriculturally dominated landscape. The demonstrated modeling approach may be useful for implementations of best management practice (BMP) and total maximum daily load (TMDL). PMID:20036451

Luo, Yuzhou; Zhang, Minghua

2010-05-01

211

Financing the "Valley of Death" : an evaluation of incentive schemes for global health businesses  

E-print Network

Many early-stage biotech companies face a significant funding gap when trying to develop a new drug from preclinical development to a proof of concept clinical trial. This funding gap is sometimes referred to as the "valley ...

Miller, Brian L. K

2009-01-01

212

DISTRIBUTION AND ABUNDANCE OF LARGE SANDHILL CRANES, GRUS CANADENSIS, WINTERING IN CALIFORNIA'S CENTRAL VALLEY  

Microsoft Academic Search

Distribution and abundance of large sandhill cranes (Grus canadensis tabida, Greater Sandhill Crane, and Grus canadensis rowani, Canadian Sandhill Crane) were studied in California's Central Valley during October-February 1983-1984 and 1984-1985. We estimated that the population contained 6,000-6,800 cranes which were concentrated at eight geographic locations from Chico to Pixley National Wildlife Refuge (NWR) near Delano. Ninety-five percent of the

THOMAS H. POGSON; SUSAN M. LINDSTEDT

213

Hydrologic reconnaissance of the Dugway Valley-Government Creek area, West-Central Utah  

USGS Publications Warehouse

The Dugway Valley-Government Creek area covers about 890 square miles (2,300 square kilometers) in west-central Utah. Total annual precipitation on the area averages about 380,000 acre-feet (470 cubic hectometers). Most streams are ephemeral except for a few in their upper reaches--all are ephemeral below the altitude of about 6,000 feet (1,830 meters). Surface-water development and use in the area are insignificant.

Stephens, Jerry C.; Sumsion, C.T.

1978-01-01

214

Simulation of Net Infiltration and Potential Recharge Using a Distributed-Parameter Watershed Model of the Death Valley Region, Nevada and California  

SciTech Connect

This report presents the development and application of the distributed-parameter watershed model, INFILv3, for estimating the temporal and spatial distribution of net infiltration and potential recharge in the Death Valley region, Nevada and California. The estimates of net infiltration quantify the downward drainage of water across the lower boundary of the root zone and are used to indicate potential recharge under variable climate conditions and drainage basin characteristics. Spatial variability in recharge in the Death Valley region likely is high owing to large differences in precipitation, potential evapotranspiration, bedrock permeability, soil thickness, vegetation characteristics, and contributions to recharge along active stream channels. The quantity and spatial distribution of recharge representing the effects of variable climatic conditions and drainage basin characteristics on recharge are needed to reduce uncertainty in modeling ground-water flow. The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, developed a regional saturated-zone ground-water flow model of the Death Valley regional ground-water flow system to help evaluate the current hydrogeologic system and the potential effects of natural or human-induced changes. Although previous estimates of recharge have been made for most areas of the Death Valley region, including the area defined by the boundary of the Death Valley regional ground-water flow system, the uncertainty of these estimates is high, and the spatial and temporal variability of the recharge in these basins has not been quantified.

J.A. Hevesi; A.L. Flint; L.E. Flint

2003-09-30

215

76 FR 16818 - Central Valley Project Improvement Act, Standard Criteria for Ag and Urban Water Management Plans  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR Bureau of Reclamation Central Valley Project Improvement Act...Management Plans AGENCY: Bureau of Reclamation, Interior. ACTION: Notice of availability...Improvement Act of 1992 (CVPIA) and the Reclamation Reform Act of 1982 (RRA), the...

2011-03-25

216

Evaluating Subsidence in the Central Valley, CA, using InSAR  

NASA Astrophysics Data System (ADS)

Satellite Interferometric Synthetic Aperture Radar (InSAR) was used to identify and characterize ground-water-induced subsidence throughout the Central Valley of California where studies show that more than 9 meters of subsidence occurred between 1925 and 1977. Subsidence measured using InSAR imagery coincides in magnitude and extent with subsidence measured during land-based geodetic surveys. Four targets in the Central Valley were chosen for this study: Highways 152 and 198 in the San Joaquin Valley; Pixley in the Wasco-Tulare area 60 km north of Bakersfield; and Davis, 15 km west of Sacramento. Precise leveling and Global Positioning System (GPS) measurements in the San Joaquin Valley (completed by the California Spatial Reference Center's San Joaquin Valley Height Modernization Project) along Highways 152 and 198 show that 1 and 2 m, respectively, of subsidence occurred from 1988 to 2003. InSAR imagery from three independent satellite tracks show a greater than 60-km-wide feature across Highway 152 and a greater than 20-km-wide deformation feature across highway 198. InSAR detects a 15- x 15-km feature just south of Pixley subsiding at a rate of about 2 cm/year between 1992 and 1995. Two overlapping satellite tracks of interferograms for this area identify a small 1.5-km-wide subsidence feature located in the southwest part of the larger-scale subsidence bowl. The maximum subsidence rate of this small-scale localized feature is approximately 35 mm/year. The Bay Area Regional Deformation (BARD) GPS site UCD1 in Davis has had an average subsidence rate of 5.7 mm/year since the site was installed in 1997. Interferograms suggest a complex seasonal deformation feature that correlates, in part, with the GPS time series.

Brandt, J. T.; Bawden, G. W.; Sneed, M.

2005-12-01

217

Rapid uplift and crustal growth in extensional environments: An isotopic study from the Death Valley region, California  

SciTech Connect

The Willow Spring Diorite, in the Black Mountains of the central Death Valley extended terrain, yields a U-Pb zircon age of 11.6 {plus minus} 0.2 Ma. {sup 40}Ar-{sup 39}Ar analyses of hornblende and U-Pb analyses of sphene from this sample give ages of about 10 Ma, indicating that the batholith remained above about 500 C for about 1.5 m.y. after crystallization. Geologic relations indicate that the diorite was exposed to erosion by about 5 Ma, bracketing the evolution of the diorite within the time between onset of extension and uplift of the Black Mountain crustal block. Initial {sup 87}Sr/{sup 86}Sr ratios range from 0.7060 (mafic diorite) to 0.7083 (felsic diorite) in samples collected from an area 200 x 100 m. These data, combined with structural and petrologic evidence, suggest that the batholith represents a rare view of a mid-crustal zone of mixing between mantle-derived magma and crustal material, often suggested to exist on the basis of observations of intermediate volcanic rocks. The Black Mountains may therefore expose a cross section through a continental rift magmatic system, from partially contaminated mafic to intermediate intrusive rocks in the deep crust up to their volcanic equivalents. The relatively low initial {sup 87}Sr/{sup 86}Sr and high {epsilon}{sub Nd} ({minus}1.4) of the diorite, which is within Proterozoic basement with {epsilon}{sub Nd} {approximately}{minus}18, is consistent with significant amounts of mantle input in continental rifts inferred from geophysical data and measurement of He isotopic ratios. Such additions to the crust in continental rights may represent a significant process of crustal growth. Furthermore, the emplacement of igneous bodies with a large mantle component may help reconcile the large crustal pull apart in the Basin and Range (in excess of 140 km) with the fact that the crust still has as normal thickness of about 30-35 km.

Asmerom, Y.; Snow, J.K.; Holm, D.K.; Jacobsen, S.B.; Wernicke, B.P. (Harvard Univ., Cambridge, MA (USA)); Lux, D.R. (Univ. of Maine, Orono (USA))

1990-03-01

218

Spatial Use by Wintering Greater White-Fronted Geese Relative to a Decade of Habitat Change in California's Central Valley  

Microsoft Academic Search

Abstract We investigated,the effect of recent,habitat changes,in Californias Central Valley on,wintering,Pacific greater,white-fronted,geese,(Anser albifrons frontalis) by comparing roost-to-feed distances, distributions, population range sizes, and habitat use during 19871990 and 1998 2000. These habitat changes included wetland restoration and agricultural land enhancement,due to the 1990 implementation of the Central Valley Joint Venture, increased land area used for rice (Oryza sativa) production, and

JOSHUA T. ACKERMAN; JOHN Y. TAKEKAWA; DENNIS L. ORTHMEYER; JOSEPH P. FLESKES; JULIE L. YEE; KAMMIE L. KRUSE

2006-01-01

219

An Integrated Geophysical Study of Hidden Valley, Central McCullough Range, NV: Characterization of a Volcanotectonic Terrain  

Microsoft Academic Search

Hidden Valley is located in the north-central McCullough Range south of Las Vegas along the western edge of the Northern Colorado River extensional corridor (NCREC) in the central Basin and Range. The western portion of the NCREC is an area of highly extended crust, but the McCullough Range is a relatively unextended block. Hidden Valley is bound on all sides

A. C. Hirsch; C. M. Snelson; E. I. Smith

2006-01-01

220

Estimated Ground-Water Withdrawals from the Death Valley Regional Flow System, Nevada and California, 1913-98  

USGS Publications Warehouse

Ground-water withdrawals from 1913 through 1998 from the Death Valley regional flow system have been compiled to support a regional, three-dimensional, transient ground-water flow model. Withdrawal locations and depths of production intervals were estimated and associated errors were reported for 9,300 wells. Withdrawals were grouped into three categories: mining, public-supply, and commercial water use; domestic water use; and irrigation water use. In this report, groupings were based on the method used to estimate pumpage. Cumulative ground-water withdrawals from 1913 through 1998 totaled 3 million acre-feet, most of which was used to irrigate alfalfa. Annual withdrawal for irrigation ranged from 80 to almost 100 percent of the total pumpage. About 75,000 acre-feet was withdrawn for irrigation in 1998. Annual irrigation withdrawals generally were estimated as the product of irrigated acreage and application rate. About 320 fields totaling 11,000 acres were identified in six hydrographic areas. Annual application rates for high water-use crops ranged from 5 feet in Penoyer Valley to 9 feet in Pahrump Valley. The uncertainty in the estimates of ground-water withdrawals was attributed primarily to the uncertainty of application rate estimates. Annual ground-water withdrawal was estimated at about 90,000 acre-feet in 1998 with an assigned uncertainty bounded by 60,000 to 130,000 acre-feet.

Moreo, Michael T.; Halford, Keith J.; La Camera, Richard J.; Laczniak, Randell J.

2003-01-01

221

Estimated Ground-water Withdrawals From the Death Valley Regional Flow System, Nevada and California, 1913-98  

SciTech Connect

Ground-water withdrawals from 1913 through 1998 from the Death Valley regional flow system have been compiled to support a regional,three-dimensional, transient ground-water flow model. Withdrawal locations and depths of production intervals were estimated and associated errors were reported for 9,300 wells. Withdrawals were grouped into three categories: mining, public-supply, and commercial water use; domestic water use; and irrigation water use. In this report, groupings were based on the method used to estimate pumpage. Cumulative ground-water withdrawals from 1913 through 1998 totaled 3 million acre-feet, most of which was used to irrigate alfalfa. Annual withdrawal for irrigation ranged from 80 to almost 100 percent of the total pumpage. About 75,000 acre-feet was withdrawn for irrigation in 1998. Annual irrigation withdrawals generally were estimated as the product of irrigated acreage and application rate. About 320 fields totaling 11,000 acres were identified in six hydrographic areas. Annual application rates for high water-use crops ranged from 5 feet in Penoyer Valley to 9 feet in Pahrump Valley. The uncertainty in the estimates of ground-water withdrawals was attributed primarily to the uncertainty of application rate estimates. Annual ground-water withdrawal was estimated at about 90,000 acre-feet in 1998 with an assigned uncertainty bounded by 60,000 to 130,000 acre-feet.

M.T. Moreo; K.J. Halford; R.J. LaCamera; and R.J. Laczniak

2003-09-30

222

The Costa Rican Central Valley Lavina Formation: Lahar or Debris Avalanche?  

NASA Astrophysics Data System (ADS)

The Lavina Formation of the Central Valley of Costa Rica consists of lava blocks floating in a volcanic mud matrix. Different authors have interpreted this deposit genetically as a lahar or debris flow deposit. Based on geomorphologic, textural, and morphometric evidence, we conclude that the origin of this deposit is a debris avalanche event that transformed into a debris flow on its path down the valley. Using aerial photographs, many debris avalanche amphitheaters are found in the western sector of the Irazu volcanic complex. However, textural and morphometric characteristics of the deposit are consistent with the source of the sector collapse being located on the west flank of the Cabeza de Vaca volcano. Three-dimensional modeling of the Lavina Formation was done using data from 213 drill cores distributed along the Central Valley area. Maps of isopaches and isohipses of the roof and floor of this stratum were created. These allowed for qualification of morphometry of the stratigraphic surfaces, characterization of the paleoslopes, and quantification of the compacted deposit volume. The data derived form the isopach and isohipse contour maps indicate that abrupt changes in the thickness of the stratum are common. Also, it illustrates the morphological differences between the roof, elongated hills in the direction of the flux, and the floor of the stratum, smooth and uniform. The morphometric, geomorphologic, and textural evidence, were used to conclude that the Lavina deposit originated as a debris avalanche event in the Cabeza de Vaca Volcano. The debris avalanche was eventually fluidized into a debris flow that spread extensively (130 km2) along the Central Valley of Costa Rica.

Hidalgo, P. J.; Alvarado Induni, G. E.; Linkimer, L.

2005-12-01

223

Fog composition in the Central Valley of California over three decades  

NASA Astrophysics Data System (ADS)

Numerous fog studies have been conducted in the Central Valley of California since the 1980s, making it one of the most studied locations in the world in terms of fog chemistry. The present work reviews observational fog studies in the area and discusses overall chemical composition as well as spatial variability and temporal variability. Regionally there is a clear gradient in fog occurrence with less fog and lower density (liquid water content, LWC) fog in the southern part of the Valley (Bakersfield) compared to more northern locations like Fresno or Davis. Chemically, fogs in the southern valley have higher solute loadings and lower pH compared to more northern locations (Davis and Fresno). Overall fog chemistry is dominated in the valley by the ammonia-nitric acid-ammonium nitrate system with sulfate being a rather minor component, especially at more northern locations and in more recent years. Fog pH in recent years is consistently higher than 5, showing an absence of acid in fogs in this region. LWC values appear to have decreased over recent years (less dense fogs). An airport visibility assessment of fog frequency reveals that overall dense fogs (visibility of less than 1/4 mile) have decreased by ~ 50% over the last 30 years.

Herckes, P.; Marcotte, A. R.; Wang, Y.; Collett, J. L.

2015-01-01

224

Hydrogeologic framework of the Wood River Valley aquifer system, south-central Idaho  

USGS Publications Warehouse

The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Hailey, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system, which consists primarily of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on groundwater for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the groundwater resource. As part of an ongoing U.S. Geological Survey effort to characterize the groundwater resources of the Wood River Valley, this report describes the hydrogeologic framework of the Wood River Valley aquifer system. Although most of the Wood River Valley aquifer system is composed of Quaternary-age sediments and basalts of the Wood River Valley and its tributaries, older igneous, sedimentary, or metamorphic rocks that underlie these Quaternary deposits also are used for water supply. It is unclear to what extent these rocks are hydraulically connected to the main part of Wood River Valley aquifer system and thus whether they constitute separate aquifers. Paleozoic sedimentary rocks in and near the study area that produce water to wells and springs are the Phi Kappa and Trail Creek Formations (Ordovician and Silurian), the Milligen Formation (Devonian), and the Sun Valley Group including the Wood River Formation (Pennsylvanian-Permian) and the Dollarhide Formation (Permian). These sedimentary rocks are intruded by granitic rocks of the Late Cretaceous Idaho batholith. Eocene Challis Volcanic Group rocks overlie all of the older rocks (except where removed by erosion). Miocene Idavada Volcanics are found in the southern part of the study area. Most of these rocks have been folded, faulted, and metamorphosed to some degree, thus rock types and their relationships vary over distance. Quaternary-age sediment and basalt compose the primary source of groundwater in the Wood River Valley aquifer system. These Quaternary deposits can be divided into three units: a coarse-grained sand and gravel unit, a fine-grained silt and clay unit, and a single basalt unit. The fine- and coarse-grained units were primarily deposited as alluvium derived from glaciation in the surrounding mountains and upper reaches of tributary canyons. The basalt unit is found in the southeastern Bellevue fan area and is composed of two flows of different ages. Most of the groundwater produced from the Wood River Valley aquifer system is from the coarse-grained deposits. The altitude of the pre-Quaternary bedrock surface in the Wood River Valley was compiled from about 1,000 well-driller reports for boreholes drilled to bedrock and about 70 Horizontal-to-Vertical Spectral Ratio (HVSR) ambient-noise measurements. The bedrock surface generally mimics the land surface by decreasing down tributary canyons and the main valley from north to south; it ranges from more than 6,700 feet in Baker Creek to less than 4,600 feet in the central Bellevue fan. Most of the south-central portion of the Bellevue fan is underlain by an apparent topographically closed area on the bedrock surface that appears to drain to the southwest towards Stanton Crossing. Quaternary sediment thickness ranges from less than a foot on main and tributary valley margins to about 350 feet in the central Bellevue fan. Hydraulic conductivity for 81 wells in the study area was estimated from well-performance tests reported on well-driller reports. Estimated hydraulic conductivity for 79 wells completed in alluvium ranges from 1,900 feet per day (ft/d) along Warm Springs Creek to less than 1 ft/d in upper Croy Canyon. A well completed in bedrock had an estimated hydraulic conductivity value of 10 ft/d, one well completed in basalt had a value of 50 ft/d, and three wells completed in the confined system had values ranging from 32 to 52 ft/

Bartolino, James R.; Adkins, Candice B.

2012-01-01

225

Calibration of a Deterministic Net Infiltration Model for the Death Valley Region Using Measured Daily Stream Flows  

NASA Astrophysics Data System (ADS)

Recharge estimates are needed to define the upper boundary conditions for groundwater flow models used to analyze water contamination and availability in the Death Valley region of southeastern California and southern Nevada. Estimated net infiltration, where net infiltration is defined as percolation below the root zone, was used as an indicator of potential recharge. Spatially distributed net infiltration was estimated using a deterministic soil-moisture model that incorporates distributed parameters to define basin characteristics, including topography, vegetation, soil properties, and bedrock geology. Daily soil moisture, evapotranspiration, runoff, surface-water discharge (stream flow), and net infiltration (based on a maximum root zone depth of 6 meters) are simulated using the defined basin characteristics and climate input consisting of continuous records of daily precipitation and air temperature from a network of monitoring sites. The deterministic model was calibrated using a trial-and-error approach of matching simulated and measured daily stream flow records at 26 stream-gaging sites in the Death Valley region. Model parameters were selected for optimization based on high uncertainty in parameter values, and were adjusted through a range of values during the calibration process. The selected parameters were bedrock hydraulic conductivity, a root-zone available water storage term for bedrock, root density coefficients for bedrock and soils, estimates of summer and winter storm durations, soil hydraulic conductivity for stream channels, and parameters defining an empirical channel flow area function. An optimized parameter set for the Death Valley region was manually created on the basis of the collective calibration results for the majority of the 26 stream flow records. Calibration of the regional-scale net infiltration model was difficult owing to: (1) available daily climate records did not accurately define the occurrence, magnitude, and spatial distribution of localized summer thunderstorms, and did not accurately define precipitation intensity for both winter and summer storms; (2) uncertainty in stream channel characteristics, such as channel geometry and soil properties; (3) divergent surface-water flow on alluvial fans and across normally dry playa lakes. Although model calibration proved to be difficult for some storms and for some of the stream-gaging sites, the net infiltration model was found to be satisfactory in predicting the general timing and magnitude of the larger, more widespread winter storms recorded for the Death Valley region. The final set of optimized parameters was developed using only winter storm events and also using comparisons of simulated monthly and annual stream discharge with recorded discharge. The calibrated net infiltration model was applied using daily climate records from 1950 through 1999 to develop an estimate of modern climate net infiltration for the Death Valley region. The net infiltration model was evaluated by comparing simulated net infiltration with published basin-wide recharge estimates from previous studies using alternative techniques, such as empirical precipitation-recharge models and the chloride mass balance method. Results from model evaluation indicate a need to expand model calibration using additional sources of data, such as snow cover and soil moisture measurements.

Hevesi, J. A.; Flint, A. L.; Flint, L. E.; Blainey, J. B.

2001-12-01

226

Hydrostructural maps of the Death Valley regional flow system, Nevada and California  

USGS Publications Warehouse

The locations of principal faults and structural zones that may influence ground-water flow were compiled in support of a three-dimensional ground-water model for the Death Valley regional flow system (DVRFS), which covers 80,000 square km in southwestern Nevada and southeastern California. Faults include Neogene extensional and strike-slip faults and pre-Tertiary thrust faults. Emphasis was given to characteristics of faults and deformed zones that may have a high potential for influencing hydraulic conductivity. These include: (1) faulting that results in the juxtaposition of stratigraphic units with contrasting hydrologic properties, which may cause ground-water discharge and other perturbations in the flow system; (2) special physical characteristics of the fault zones, such as brecciation and fracturing, that may cause specific parts of the zone to act either as conduits or as barriers to fluid flow; (3) the presence of a variety of lithologies whose physical and deformational characteristics may serve to impede or enhance flow in fault zones; (4) orientation of a fault with respect to the present-day stress field, possibly influencing hydraulic conductivity along the fault zone; and (5) faults that have been active in late Pleistocene or Holocene time and areas of contemporary seismicity, which may be associated with enhanced permeabilities. The faults shown on maps A and B are largely from Workman and others (in press), and fit one or more of the following criteria: (1) faults that are more than 10 km in map length; (2) faults with more than 500 m of displacement; and (3) faults in sets that define a significant structural fabric that characterizes a particular domain of the DVRFS. The following fault types are shown: Neogene normal, Neogene strike-slip, Neogene low-angle normal, pre-Tertiary thrust, and structural boundaries of Miocene calderas. We have highlighted faults that have late Pleistocene to Holocene displacement (Piety, 1996). Areas of thick Neogene basin-fill deposits (thicknesses 1-2 km, 2-3 km, and >3 km) are shown on map A, based on gravity anomalies and depth-to-basement modeling by Blakely and others (1999). We have interpreted the positions of faults in the subsurface, generally following the interpretations of Blakely and others (1999). Where geophysical constraints are not present, the faults beneath late Tertiary and Quaternary cover have been extended based on geologic reasoning. Nearly all of these concealed faults are shown with continuous solid lines on maps A and B, in order to provide continuous structures for incorporation into the hydrogeologic framework model (HFM). Map A also shows the potentiometric surface, regional springs (25-35 degrees Celsius, D'Agnese and others, 1997), and cold springs (Turner and others, 1996).

Potter, C.J.; Sweetkind, D.S.; Dickerson, R.P.; Killgore, M.L.

2002-01-01

227

Mesozoic burial, Mesozoic and Cenozoic exhumation of the Funeral Mountains core complex, Death Valley, Southeastern California  

NASA Astrophysics Data System (ADS)

The Funeral Mountains of Death Valley National Park, CA, provide an opportunity to date metamorphism resulting from crustal shortening and subsequent episodic extensional events in the Sevier hinterland. It was not clear whether crustal shortening and thus peak temperature metamorphism in the hinterland of the Sevier-Laramide orogenic wedge have occurred whether in Late Jurassic, Early Cretaceous, Late Cretaceous or somewhere between. Particularly ambiguous is the timing of crustal shortening in the deep levels of the hinterland of the Sevier belt, now manifest in the metamorphic core complexes, and how and when these middle-to-lower crustal rocks were exhumed. A 6-point garnet and a whole rock Savillax isochron from middle greenschist facies pelitic schist of the southeastern Funeral Mountains core complex yields an age of 162.1 +/- 5.8 Ma (2sigma). Composite PT paths determined from growth-zoned garnets from the same samples show a nearly isothermal pressure increase of 2 kbar at 490C, suggesting thrust burial at 162.1 +/- 5.8 Ma. A second sample of Johnnie Formation from the comparatively higher metamorphic grade area to the northwest (East of Chloride Cliff) yielded an age of 172.9 +/- 4.9 Ma (2sigma) suggesting an increase of thrust burial age towards the higher grade rocks (northwest part of the core complex), consistent with paleo-depth interpretation and metamorphic grade. 40Ar/ 39Ar muscovite ages along footwall of the Boundary Canyon detachment fault and intra-core Chloride Cliff shear zone exhibit significant 40Ar/39Ar muscovite age differences. For samples from the immediate footwall of BCD, the pattern of ages decreasing toward the northwest is consistent with differences in depth of metamorphism, and for Late Cretaceous, top-to-northwest exhumation by motion along the precursor BCD; consistent with mesoscopic and microscopic kinematic studies. Samples from the footwall of the structurally-lower Chloride Cliff shear zone yield Tertiary 40Ar/39Ar muscovite ages (53 to 29 Ma) and interpreted to reflect a more youthful age of extensional ductile deformation confined along the CCSZ. (U-Th)/He analyses on detrital zircon (ZrHe) from quartzite samples collected along the footwall of the BCD along the same transect as the 40Ar/39Ar samples revealed inception of the Miocene BCD at 10-11 Ma. A slip rate of 8.5 +/-2.0 km/Ma was determined excluding three analyses that significantly deviate from the regression line. This study indicate that the core rocks of the Funeral Mountains were buried during Late Jurassic, and then slowly exhumed, probably by erosion between 152 and 90 Ma, and then more rapidly exhumed initially by movement along the precursor of the BCD during Late Cretaceous. Following a hiatus of tectonic activity, exhumation resumed during late early Tertiary with deformation likely confined along discrete ductile shear zones. The latest period of motion along the BCD and thus the final exhumation of metamorphosed core rocks in the Funeral Mountains has initiated 11-10 Ma and likely ceased around 6 Ma, consistent with ages of motions of detachment faults and exhumation of footwall rocks in the surrounding mountain ranges.

Beyene, Mengesha Assefa

2011-12-01

228

Hydrogeologic Framework and Ground Water in Basin-Fill Deposits of the Diamond Valley Flow System, Central Nevada  

USGS Publications Warehouse

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 Valley, flow is from valley margins toward the irrigated area. In northern Diamond Valley, flow appears to remain generally northward to the large discharge area. Subsurface flow through mountain ranges has been identified from Garden Valley (outside the study area) through the Sulphur Springs Range to Diamond Valley and from southeastern Antelope Valley through the Fish Creek Range to Little Smoky Valley (outside the study area). In both cases, the flow is probably through carbonate rocks. Ground-water levels in the Diamond Valley flow system have changed during the past 40 years. These changes are the result of pumpage for irrigation, municipal, domestic, and mining uses, mostly in southern Diamond Valley, and annual and longer-term variations in precipitation in undeveloped parts of the study area. A large area of ground-water decline that underlies an area about 10 miles wide and 20 miles long has developed in the basin-fill aquifer of southern Diamond Valley. Water levels beneath the main part of the irrigated area have declined as much as 90 feet. In undeveloped parts of the study area, annual water-level fluctuations generally have been no more than a few feet.

Tumbusch, Mary L.; Plume, Russell W.

2006-01-01

229

InSAR Reveals a Potpourri of Deformation Signals in the Yucca Mountain -- Amargosa Valley -- Death Valley Region, Southwestern Nevada/Southeastern California  

NASA Astrophysics Data System (ADS)

InSAR studies have revealed a variety of surface deformation signals attributed to several causes in the Yucca Mountain -- Amargosa Valley -- Death Valley region. This study utilizes 26 ERS 1 and 2 scenes to produce 34 interferometric pairs that cover the period of 1992 - 2000. Prominent signals that have been previously studied include the 1992 Little Skull Mountain Earthquake and groundwater subsidence in the Pahrump Valley (Lohman et al., 2002, and Utley, 2005). Several subsidence signals (2.5 -- 3.5 cm) present within Amargosa Valley represent aquifer response in close proximity to local groundwater withdrawal. Observed groundwater level declines in the vicinity of the subsidence bowls are also present. However, signals near Amargosa Flat and Ash Meadows National Wildlife Refuge appear to be a more complex regional aquifer response related either to distant groundwater use or other hydrologic processes related to the abundant spring activity in the area as groundwater levels have remained fairly steady in these regions. A subsidence signal at Frenchman Flat, within the Nevada Test Site, shows approximately 2 cm of subsidence with the majority occurring between 1998 and 2000. Groundwater use in this area was actually lower during this time period than during the previous six years covered by this study, and monitoring wells suggest a relatively constant depth to groundwater with no notable trend up or down. This suggests another mechanism behind the subsidence, including the possibility that three nuclear blast centers located within the subsidence bowl have altered groundwater recharge conditions in the area. The signal with the largest magnitude is related to mining activity at the Bullfrog Mine located west of Beatty, NV. At this location, as much as 8 cm of subsidence, occurring between 1995 and 2000, is centered on the eastern edge of the mine site and extends into the bedrock to the northeast. GPS data (Bennett et al, 2003 and Wernicke et al, 2004) suggest that a velocity contrast of approximately 3.5 mm/yr exists between the Yucca Mountain Block and the Furnace Creek Fault in eastern Death Valley. Unit vector values for the SAR data suggest that this velocity contrast translates to a line of sight (LOS) change of approximately 0.90 -- 0.95 mm/year. Therefore, over the eight year study period, a total LOS change of approximately 0.7 -- 0.8 cm is theorized. Although this LOS change is large enough to be detected using InSAR, this study was unable to detect and locate a signal that could be confidently attributed to this velocity contrast. This is likely due to the wide aperture over which the shear is acting, as well as topographic interference inherent in InSAR studies in regions of variable relief. This study was supported by NASA grant NAG 13 -- 02017.

Katzenstein, K. W.; Bell, J. W.

2005-12-01

230

Strike-Slip displacement along the Furnace Creek Fault Zone, southern Basins and Ranges, Death Valley, California  

NASA Astrophysics Data System (ADS)

The southern Basins and Ranges contain several strike-slip fault zones in addition to predominant normal faults. One of the strike-slip faults is the Furnace Creek fault zone (FCFZ) which extends from the Amorgosa Valley in eastern California northwestward continuously about 200 km and terminates in the Fish Lake Valley in Nevada. The fault zone is a part of the Eastern California Shear Zone. Although the right-lateral sense of strike-slip movement along the FCFZ is undisputed, the magnitude of displacement has been controversial since the 1970s. Recently, we have mapped conglomerates exposed in the Travertine point area of the Furnace Creek Wash of the Death Valley region. The conglomerates are composed of Paleozoic clasts from the following formations: Bonanza King, Nopah, Pogonip, Eureka Quartzite, Hidden Valley, and Ely Springs Dolomite. Our analysis of these breccias showed that they are made out of clasts of one composition and a matrix that was slightly different. This observation and our microscopic analysis suggest to us that these breccias were formed as fault breccias along the Furnace Creek fault zone. We have also mapped breccias in the Desolation Canyon on the southwestern side of the FCFZ where the Bonanza King Formation is brought into structural contact over the Ely Spring Dolomite and Eureka Quartzite suggesting the presence of a thrust fault. We correlate this thrust fault with a similar structural setting along the Clery Thrust of the southern Funeral Mountains on northeastern sides of the FCFZ where the Clery thrust brings the Cambrian Bonanza King Formation over the Eureka Quartzite and Ely Spring Dolomite in the southern Funeral Mountains. These observations suggest to us that the thrust fault in the Desolation Canyon area is the continuation of the Clery Thrust of the southern Funeral Mountains. If this interpretation is correct, the strike-slip displacement along the FCFZ is about 30 km.

Baucke, W.; Cemen, I.

2007-12-01

231

Quantitative investigations of geologic surfaces utilizing airborne visible/infrared imaging spectrometer (AVIRIS) and polarimetric radar (AIRSAR) data for Death Valley, California  

NASA Technical Reports Server (NTRS)

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and polarimetric radar (AIRSAR) data were collected over Death Valley, California, USA, in September 1989. These two data sets were used to quantitatively characterize both the mineralogy and surface structure of the valley floor. Field mapping and characterization of the salt flats across the valley identified 16 separate units. The AVIRIS data were calibrated using the 'empirical line' method, and spectra extracted for the 16 units. A water vapor map was generated from the AVIRIS data and showed spatial variations in its distribution due to evaporation of surface water. Unmixing of the 16 spectral units produced maps of endmember abundance.

Kierein-Young, Kathryn S.; Kruse, Fred A.

1991-01-01

232

[The role of certain sections of the central nervous system in the genesis of sudden death].  

PubMed

Hypothalamic and hippocampal lipid composition in sudden death from coronary heart disease is studied. Thin-layer chromatography was the main method of biochemical analysis. Disorders in the lipid component of hippocampal cytostructures involved mainly the cholesterol fractions. Metabolic disorders in the hypothalamus involved the phospholipid metabolism. The above-mentioned biochemical changes were paralleled by ultrastructural abnormalities. Analysis of the data demonstrates a probable metabolic basis of a central mechanism of sudden cardiac death. PMID:10467862

Dubrovin, I A; Chelnokov, V S; Kalinkin, M N

1999-01-01

233

A guide for using the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California  

USGS Publications Warehouse

This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

Blainey, Joan B.; Faunt, Claudia C.; Hill, Mary C.

2006-01-01

234

A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California  

SciTech Connect

This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

2006-05-16

235

Distribution of Oncomelania hupensis in the Napu Valley of Central Sulawesi, Indonesia.  

PubMed

Fifteen colonies of Oncomelania hupensis were found near trails transecting the North Lore District, Napu Valley, Central Sulawesi. Habitats were in abandoned rice fields, uncultivated grazing areas for livestock, roadside ditches and, in one case, an actively worked rice field. Marsh grasses, Ischaemum barbatum and Laersia hexandra, were the most common plants in oncomelanid habitats. Other mollusks found in association with O. hupensis were Radix sp., Melanoides sp., Gyraulus sp., Idiopoma sp., Thiara sp., Opeas sp. and Indopyrgus sp. in that order of frequency. Schistosoma japonicum cercariae, as determined by mouse exposures, were shed from snails collected at four foci. In Sulawesi, O. hupensis and S. japonicum were found in high mountain valleys near, or above, 1,000 meters in elevation. Oncomelania hupensis, however, were not found in what appeared to be suitable habitats at lower elevations in the same drainage systems. PMID:1166348

Carney, W P; Masri, S; Sudomo, M; Putrali, J; Davis, G M

1975-06-01

236

Hydrology of Prairie Dog Creek Valley, Norton Dam to state line, north-central Kansas  

USGS Publications Warehouse

Development of water resources has been a major factor in the economy of Prairie Dog Creek Valley in north-central Kansas. Releases from Norton Reservoir to the Almena Irrigation District averaged 6,900 acre-feet per year during 1967-76. The number of irrigation wells increased from 4 to 147 during 1947-78. Ground water in the valley is derived mostly from the alluvial aquifer. The effects of irrigation on the aquifer are indicated by water-level changes. The water in storage increased from 130,000 to 136,000 acre-feet during 1947-78 due to recharge from surface-water irrigation. A steady-state model of the aquifer prior to irrigation (1947) indicated that most recharge was from precipitation (88 percent) and most discharge was to streams (54 percent) and reparian transpiration (26 percent). Although aquifer storage increased in this area, storage generally decreased in other areas of western Kansas. (USGS)

Stullken, L.E.

1984-01-01

237

The role of Thurwieser rock avalanche in the geomorphological evolution of Zebr Valley (Italian Central Alps)  

NASA Astrophysics Data System (ADS)

On September 18th, 2004 a rock avalanche with an estimated volume of 2.5 M m3 propagated from the southern flank of Punta Thurwieser, affecting the Mar Valley, a tributary located in upper part of Zebr Valley, 30 Km East from Bormio, in the Italian Central Alps. The landslide event deposited a thick debris cover on the pre-landslide morphology up to 2.2 Km from the source area. In this contribution, we aim at studying the role of the rock avalanche on the geomorphological evolution of the valley and in particular in controlling the evolution of the drainage system, the sediment budget and the mass balance of Zebr glacier. In fact, after ten years it is possible to appreciate and valuate how such an event could modify the landscape and the geomorphology of an alpine valley. First, the landslide body formed a robust obstacle splitting the original watershed into two different sub-units. This caused a different distribution of the sediment yield rate in the upper part of the valley. As a consequence, an extremely rapid excavation of a new channel took place, ending in a new debris fan along the Zebr valley bottom. A consistent groundwater flow still occurs within the rock avalanche deposit along the old valley axis, excepted for periods characterized by intense precipitation and snow melting events, which are able to activate the recently developed drainage channel. Thus implies that the main transport of sediments will occur along the new channel, during periods of high discharge. In the middle part of the landslide deposit, a sediment trap formed, collecting the material eroded by the surrounding ridges and by the upper sector of the deposit itself, forming a small plain under constant accretion. From this temporary trap, it was possible to estimate the periglacial sediment transport yield of the basin. The Zebr glacier, flowing from the Mt Zebr peak, was partially interested from the landslide, which covered a portion of the ice tongue with a shallow layer of blocks and finer matrix. The Thurwieser debris acted as a thermal insulation, preserving a significant ice volume and building up a steep bound, in the order of 10 m high, between non-covered and covered glacier surface. Topographic data collected since 2004 are presented and analyzed in this contribution to study the evolution both at a large and small scale.

Riva, Federico; Frattini, Paolo; Greggio, Luca; Crosta, Giovanni B.

2014-05-01

238

Late Cenozoic sedimentation and volcanism during transtensional deformation in Wingate Wash and the Owlshead Mountains, Death Valley  

USGS Publications Warehouse

New 1:24,000 scale mapping, geochemical analyses of volcanic rocks, and Ar/Ar and tephrochronology analyses of the Wingate Wash, northern Owlshead Mountain and Southern Panamint Mountain region document a complex structural history constrained by syntectonic volcanism and sedimentation. In this study, the region is divided into five structural domains with distinct, but related, histories: (1) The southern Panamint domain is a structurally intact, gently south-tilted block dominated by a middle Miocene volcanic center recognized as localized hypabyssal intrusives surrounded by proximal facies pyroclastic rocks. This Miocene volcanic sequence is an unusual alkaline volcanic assemblage ranging from trachybasalt to rhyolite, but dominated by trachyandesite. The volcanic rocks are overlain in the southwestern Panamint Mountains by a younger (Late Miocene?) fanglomerate sequence. (2) An upper Wingate Wash domain is characterized by large areas of Quaternary cover and complex overprinting of older structure by Quaternary deformation. Quaternary structures record ???N-S shortening concurrent with ???E-W extension accommodated by systems of strike-slip and thrust faults. (3) A central Wingate Wash domain contains a complex structural history that is closely tied to the stratigraphic evolution. In this domain, a middle Miocene volcanic package contains two distinct assemblages; a lower sequence dominated by alkaline pyroclastic rocks similar to the southern Panamint sequence and an upper basaltic sequence of alkaline basalt and basanites. This volcanic sequence is in turn overlain by a coarse clastic sedimentary sequence that records the unroofing of adjacent ranges and development of ???N-S trending, west-tilted fault blocks. We refer to this sedimentary sequence as the Lost Lake assemblage. (4) The lower Wingate Wash/northern Owlshead domain is characterized by a gently north-dipping stratigraphic sequence with an irregular unconformity at the base developed on granitic basement. The unconformity is locally overlain by channelized deposits of older Tertiary(?) red conglomerate, some of which predate the onset of extensive volcanism, but in most of the area is overlain by a moderately thick package of Middle Miocene trachybasalt, trachyandesitic, ash flows, lithic tuff, basaltic cinder, basanites, and dacitic pyroclastic, debris, and lahar flows with localized exposures of sedimentary rocks. The upper part of the Miocene stratigraphic sequence in this domain is comprised of coarse grained-clastic sediments that are apparently middle Miocene based on Ar/Ar dating of interbedded volcanic rocks. This sedimentary sequence, however, is lithologically indistinguishable from the structurally adjacent Late Miocene Lost Lake assemblage and a stratigraphically overlying Plio-Pleistocene alluvial fan; a relationship that handicaps tracing structures through this domain. This domain is also structurally complex and deformed by a series of northwest-southeast-striking, east-dipping, high-angle oblique, sinistral, normal faults that are cut by left-lateral strike-slip faults. The contact between the southern Panamint domain and the adjacent domains is a complex fault system that we interpret as a zone of Late Miocene distributed sinistral slip that is variably overprinted in different portions of the mapped area. The net sinistral slip across the Wingate Wash fault system is estimated at 7-9 km, based on offset of Proterozoic Crystal Springs Formation beneath the middle Miocene unconformity to as much as 15 km based on offset volcanic facies in Middle Miocene rocks. To the south of Wingate Wash, the northern Owlshead Mountains are also cut by a sinistral, northwest-dipping, oblique normal fault, (referred to as the Filtonny Fault) with significant slip that separates the Lower Wingate Wash and central Owlshead domains. The Filtonny Fault may represent a young conjugate fault to the dextral Southern Death Valley fault system and may be the northwest

Luckow, H.G.; Pavlis, T.L.; Serpa, L.F.; Guest, B.; Wagner, D.L.; Snee, L.; Hensley, T.M.; Korjenkov, A.

2005-01-01

239

Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California  

SciTech Connect

A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year. To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for locations such as the Spring Mountains. Although this model is preliminary and uncalibrated, it provides a first approximation of the spatial distribution of net infiltration for the Death Valley region under current climatic conditions.

Hevesi, J.A.; Flint, A.L.; Flint, L.E.

2002-07-18

240

Geologic Utility of LANSDAT-4 TM Data. [Death Valley, California and the Silver Bell area of southern Arizona  

NASA Technical Reports Server (NTRS)

The performance of the TM vis-a-vis various geological applications was quantified by analyzing: (1) the geological utility of the data with respect to the increased spatial resolution and number of bands (compared to the MSS); (2) the geometric accuracy; (3) the radiometric performance of the TM scanner. Preliminary analyses were performed on TM scenes: over Death Valley, California, and over southern Arizona. Both scenes were acquired in CCT-PT format, where the data were geometrically and radiometrically corrected. Overall, the TM data appears to contain a marked increase in geologically useful information; however, a number of instrumental or processing artifacts may well limit the ability of the geologist to fully extract this information.

Abrams, M.; Kahle, A. B.; Gillespie, A.; Conel, J.; Lang, H.

1985-01-01

241

Geologic mapping in Death Valley, California/Nevada using NASA/JPL airborne systems (AVIRIS, TIMS, and AIRSAR)  

NASA Technical Reports Server (NTRS)

A multi-sensor aircraft campaign called the Geologic Remote Sensing Field Experiment (GRSFE) conducted during 1989 resulted in acquisition of high quality multispectral images in the visible, near infrared, shortwave infrared, thermal infrared, and microwave regions of the electromagnetic spectrum. The airborne data sets include the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), the Thermal Infrared Multispectral Scanner (TIMS), and the Airborne Synthetic Aperture Radar (SAR). Ancillary data include Landsat Thematic Mapper, laboratory and field spectral measurements, and traditional geologic mapping. The GRSFE data for a site in the northern Death Valley, (California and Nevada) region were calibrated to physical units and geometrically registered to a map base. Various aspects of this experiment are briefly discussed.

Kruse, Fred A.; Dietz, John B.; Kiereinyoung, Kathryn S.

1991-01-01

242

The Valley-of-Death: reciprocal sign epistasis constrains adaptive trajectories in a constant, nutrient limiting environment.  

PubMed

The fitness landscape is a powerful metaphor for describing the relationship between genotype and phenotype for a population under selection. However, empirical data as to the topography of fitness landscapes are limited, owing to difficulties in measuring fitness for large numbers of genotypes under any condition. We previously reported a case of reciprocal sign epistasis (RSE), where two mutations individually increased yeast fitness in a glucose-limited environment, but reduced fitness when combined, suggesting the existence of two peaks on the fitness landscape. We sought to determine whether a ridge connected these peaks so that populations founded by one mutant could reach the peak created by the other, avoiding the low-fitness "Valley-of-Death" between them. Sequencing clones after 250 generations of further evolution provided no evidence for such a ridge, but did reveal many presumptive beneficial mutations, adding to a growing body of evidence that clonal interference pervades evolving microbial populations. PMID:25449178

Chiotti, Kami E; Kvitek, Daniel J; Schmidt, Karen H; Koniges, Gregory; Schwartz, Katja; Donckels, Elizabeth A; Rosenzweig, Frank; Sherlock, Gavin

2014-12-01

243

Geomorphological analysis of the Lower Tagus Valley Fault Zone, Central Portugal.  

NASA Astrophysics Data System (ADS)

The Lower Tagus Valley Fault Zone (LTVFZ) is a northeast-southwest trending tectonic structure located within the Lower Tagus Valley (LTV), in central Portugal associated with at least two historical events: the 1909 Mw 6.0-6.2 Benavente earthquake and the 1531 Mw 6.9 earthquake. Recent investigations indicate that the relatively linear valley associated with the Lower Tagus River is controlled by active faults in varying geometry and slip rates. Based on mapped traces, LTVFZ is about 80 kilometers long and transects Miocene to late Quaternary deposit. The east and west strands of the fault zone may have different level of activity based on the variable clarity of mapped morphological expressions. In this work, new fault strands were identified using aerial photos on eastern side of LTV. These eastern faults has a trend that almost parallel those active traces previously mapped by Besana-Ostman et al., 2012 on the western side of the valley. The newly-mapped faults has left-lateral strike-slip movements and can be separated into two segments based on the kinematic indicators like offsets on river, ridges, and valley together with fluvial terraces displacements. Until this study, no Holocene fault scarps have been identified on the eastern portion of the LTV. Quaternary activity of faults can be assessed by the evaluation of morphometric indexes. In case of LTVFZ, the most characteristic landforms are fault-generated mountain fronts and valleys where the mountain front sinuosity index Smf is measured for fault activity evaluation. Through this morphometric index, mountain fronts are classified into Class I (Smf 1-1.4); active, Class II (Smf 1.4-2.5); intermediate, and Class III (Smf >2.5); inactive. In this paper, the Smf is calculated for the western and eastern sides of LTV as 1.3 and 1.8, respectively. These Smf values indicate that the western mountain front of the LTV corresponds to Class I while the eastern mountain front is Class II. However, considering the possible two segments of the eastern fault, the index of the northern segment produced 1.35 that indicates an active mountain front (Smf class I). This study, although preliminary, established additional active traces for the LTVFZ with the potential to generate M6 or greater earthquakes. This is very important because the LTV is the most populated and developed region of SW Iberia with the highest level of seismic hazard.

Canora-Catalan, Carolina; Besana-Ostman, Glenda; Vilanova, Susana; Fonseca, Joao; Pinto, Luis; Domingues, Ana; Narciso, Joao; Pinheiro, Patricia

2013-04-01

244

Perspective: Transforming science into medicine: how clinician-scientists can build bridges across research's "valley of death".  

PubMed

Significant increases in National Institutes of Health (NIH) spending on medical research have not produced corresponding increases in new treatments and cures. Instead, laboratory discoveries remain in what has been termed the "valley of death," the gap between bench research and clinical application. Recently, there has been considerable discussion in the literature and scientific community about the causes of this phenomenon and how to bridge the abyss. In this article, the authors examine one possible explanation: Clinician-scientists' declining role in the medical research enterprise has had a dilatory effect on the successful translation of laboratory breakthroughs into new clinical applications. In recent decades, the percentage of MDs receiving NIH funding has drastically decreased compared with PhDs. The growing gap between the research and clinical enterprises has resulted in fewer scientists with a true understanding of clinical problems as well as scientists who are unable to or uninterested in gleaning new basic research hypotheses from failed clinical trials. The NIH and many U.S. medical schools have recognized the decline of the clinician-scientist as a major problem and adopted innovative programs to reverse the trend. However, more radical action may be required, including major changes to the NIH peer-review process, greater funding for translational research, and significantly more resources for the training, debt relief, and early career support of potential clinician-scientists. Such improvements are required for clinician-scientists to conduct translational research that bridges the valley of death and transforms biomedical research discoveries into tangible clinical treatments and technologies. PMID:22373616

Roberts, Scott F; Fischhoff, Martin A; Sakowski, Stacey A; Feldman, Eva L

2012-03-01

245

A Comparison of Groundwater Storage Using GRACE Data, Groundwater Levels, and a Hydrological Model in Californias Central Valley  

NASA Technical Reports Server (NTRS)

The Gravity Recovery and Climate Experiment (GRACE) measures changes in total water storage (TWS) remotely, and may provide additional insight to the use of well-based data in California's agriculturally productive Central Valley region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques may prove useful. From October 2002 to September 2009, GRACE was used to map changes in TWS for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater- Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. The results from the three methods were compared. Downscaling GRACE data into the 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater resource management and use of existing hydrological models for the Central Valley.

Kuss, Amber; Brandt, William; Randall, Joshua; Floyd, Bridget; Bourai, Abdelwahab; Newcomer, Michelle; Skiles, Joseph; Schmidt, Cindy

2011-01-01

246

A comparison of groundwater storage using GRACE data, groundwater levels, and a hydrological model in California's Central Valley  

NASA Astrophysics Data System (ADS)

The Gravity Recovery and Climate Experiment (GRACE), a NASA satellite sensor, measures changes in total water storage (TWS) and may provide additional insight to the use of well-based data in California's Central Valley, an important agricultural region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques must be used. GRACE was used to map changes in TWS between October 2002 and September 2009 for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater-Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. Downscaling GRACE data into 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater measurements and existing hydrological models for the Central Valley.

Floyd, B.; Kuss, A. M.; Brandt, W. T.; Randall, J. N.; Bourai, A.; Newcomer, M. E.; Schmidt, C.; Skiles, J. W.

2011-12-01

247

Morrow Formation facies geometries and reservoir quality in compound valley fills, central State line area, Colorado and Kansas  

Microsoft Academic Search

Pennsylvanian Morrow valley-fill reservoirs are highly productive from a 2-km wide, 32-km long group of fields along the central Colorado and Kansas border. Many wells can produce 200-800 bbl\\/day, but 40-acre offsets to these wells with similar pay thicknesses and well log characteristics can be nonproductive. Variable production is caused by complex facies relationships created when a coarse, permeable valley

Lee F. Krystinik

1989-01-01

248

Depositional environments and sedimentary tectonics of subsurface Cotton Valley group (upper Jurassic), west-central Mississippi  

SciTech Connect

Study of data from 65 selected wells in a 6-county area (about 60 by 60 mi) north and west of Jackson, Mississippi, discloses that Cotton Valley strata, now within the axial trough of the Mississippi embayment, display thickness variations which demonstrate that Late Jurassic sedimentation was strongly controlled by maximum subsidence along the same trough axis. Examination of well logs, other records, and cutting sets from 38 wells has resulted in preparation of dip and strike cross sections that permit information definition of lower, middle, and upper parts of the Cotton Valley Group throughout the area evaluated. Within these lithostratigraphic diversions, lithofacies are discriminable that represent alluvial, upper delta plain, lower delta plain, and prodeltaic environments. These facies display a general variation from coarse, commonly red, oxidized sediments on the north and east, to mudrocks, locally calcareous and carbonaceous, on the southwest. Within the Cotton Valley Group examined, two persistent clastic lobes demonstrate relative environmental stability while deposits ranging in thickness from 1500 ft (northwestern corner of study area) to 4500 ft (axial depocenter on the south) accumulated. During Cotton Valley deposition, west-central Mississippi was the site of a two-toed birdfoot delta within which lignites were deposited. Major sediment supply was from the east and north; a minor source was to the northwest (Ouachita-Ozarks). Irregulatories in both rates of supply of clastics and of shelf subsidence permitted intermittent shallow, clear-water, marine incursions from the south during which thin carbonate beds were deposited, interfingering with the clastics. Thus, potential source and host rocks for hydrocarbon traps are closely associated, for thick, organic-rich, interlobate mudrocks pass laterally and vertically into fluvial sands of the delta lobes.

Sydboten, B.D. Jr.; Bowen, R.L.

1987-09-01

249

Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front  

Microsoft Academic Search

Controversy exists over whether alluvial-fan sedimentation along tectonically active mountain fronts is driven by climatic changes or tectonics. Knowing the age of sedimentation is the key to understanding the relationship between sedimentation and its cause. Alluvial-fan deposits in Death Valley and throughout the arid southwestern United States have long been the subjects of study, but their ages have generally eluded

M. F. Sohn; S. A. Mahan; J. R. Knott; D. D. Bowman

2007-01-01

250

Hydraulic-property estimates for use with a transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California  

USGS Publications Warehouse

The Death Valley regional ground-water flow system encompasses an area of about 43,500 square kilometers in southeastern California and southern Nevada, between latitudes 35? and 38?15' north and longitudes 115? and 117?45' west. The study area is underlain by Quaternary to Tertiary basin-fill sediments and mafic-lava flows; Tertiary volcanic, volcaniclastic, and sedimentary rocks; Tertiary to Jurassic granitic rocks; Triassic to Middle Proterozoic carbonate and clastic sedimentary rocks; and Early Proterozoic igneous and metamorphic rocks. The rock assemblage in the Death Valley region is extensively faulted as a result of several episodes of tectonic activity. This study is comprised of published and unpublished estimates of transmissivity, hydraulic conductivity, storage coefficient, and anisotropy ratios for hydrogeologic units within the Death Valley region study area. Hydrogeologic units previously proposed for the Death Valley regional transient ground-water flow model were recognized for the purpose of studying the distribution of hydraulic properties. Analyses of regression and covariance were used to assess if a relation existed between hydraulic conductivity and depth for most hydrogeologic units. Those analyses showed a weak, quantitatively indeterminate, relation between hydraulic conductivity and depth.

Belcher, Wayne R.; Elliott, Peggy E.; Geldon, Arthur L.

2001-01-01

251

Hydraulic-property estimates for use with a transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California  

SciTech Connect

The Death Valley regional ground-water flow system encompasses an area of about 43,500 square kilometers in southeastern California and southern Nevada. The study area is underlain by Quaternary to Tertiary basin-fill sediments and mafic-lava flows; Tertiary volcanic, volcaniclastic, and sedimentary rocks; Tertiary to Jurassic granitic rocks; Triassic to Middle Proterozoic carbonate and clastic sedimentary rocks; and Early Proterozoic igneous and metamorphic rocks. The rock assemblage in the Death Valley region is extensively faulted as a result of several episodes of tectonic activity. This study is comprised of published and unpublished estimates of transmissivity, hydraulic conductivity, storage coefficient, and anisotropy ratios for hydrogeologic units within the Death Valley region study area. Hydrogeologic units previously proposed for the Death Valley regional transient ground-water flow model, were recognized for the purpose of studying the distribution of hydraulic properties. Analyses of regression and covariance were used to assess if a relation existed between hydraulic conductivity and depth for most hydrogeologic units. Those analyses showed a weak, quantitatively indeterminate, relation between hydraulic conductivity and depth.

W.R. Belcher; P.E. Elliott; A.L. Geldon

2001-12-31

252

Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations  

USGS Publications Warehouse

Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologic infrastructure and management affect streamflow characteristics of rivers in the Central Valley, California and discuss those characteristics in the context of habitat requirements of native and alien fishes. We evaluated the effects of water management by comparing observed discharges with estimated discharges assuming no water management ("full natural runoff"). Rivers in the Sacramento River drainage were characterized by reduced winterspring discharges and augmented discharges in other months. Rivers in the San Joaquin River drainage were characterized by reduced discharges in all months but particularly in winter and spring. Two largely unaltered streams had hydrographs similar to those based on full natural runoff of the regulated rivers. The reduced discharges in the San Joaquin River drainage streams are favourable for spawning of many alien species, which is consistent with observed patterns of fish distribution and abundance in the Central Valley. However, other factors, such as water temperature, are also important to the relative success of native and alien resident fishes. As water management changes in response to climate change and societal demands, interdisciplinary programs of research and monitoring will be essential for anticipating effects on fishes and to avoid unanticipated ecological outcomes.

Brown, Larry R.; Bauer, Marissa L.

2010-01-01

253

Spatially Distributed Exposure Assessment of Pesticide Sources in the Central Valley, California, USA  

NASA Astrophysics Data System (ADS)

Pesticides in agricultural runoff are considered as significant pollution from nonpoint sources in intensive agricultural regions such as Californias Central Valley. This study presents a spatially explicit modeling approach to extend field-scale pesticide transport model into basin level. The approach was applied to simulate chlorpyrifos use in the Central Valley during 2003-2007. Chlorpyrifos loadings were reported for each section (11 mi cell), and the simulation results were in general agreements with monitoring results at watershed level. The average value of loading as percent of use (LAPU) is 0.031% and varied with seasons and locations. Results of this study provide strong evidence that surface runoff generation and pesticide application timing are the two influencing factors on the spatial and temporal variability of chlorpyrifos sources from agricultural fields. This is one of the first studies in coupling GIS and field-scale models and providing simulations for the dynamics of pesticides over an agriculturally dominated landscape. The demonstrated modeling approach may be useful for assessment of the implementations of best management practice (BMPs) and total maximum daily load (TMDL).

Luo, Y.; Zhang, M.

2009-12-01

254

Estimating Reference Evaporation in the Central Valley of California Using the Linacre Model  

NASA Astrophysics Data System (ADS)

The Linacre (1988) model for calculating evaporation from open water or well-watered surfaces only requires inputs of air temperature, latitude and elevation, and windspeed if it is available. The model was developed using data collected at a large number of sites in different climatic regions of the world, while independent tests of the model have shown it to be suitable for estimating evaporation in a variety of locations. This study was intended to contribute to the broad goal of evaluating temperature-based evaporation models for use in California by testing the Linacre model in the agriculturally intensive Central Valley. Observed monthly mean reference evaporation (E0) and meteorological data for periods ranging up to 72 months were obtained from 25 California Irrigation and Management Information System (CIMIS) stations distributed throughout the Central Valley. Uncalibrated and calibrated Linacre models were used to estimate monthly mean reference evaporation, and the performance of each model was evaluated using indices that quantified the random and systematic errors and overall model performance. The accuracy of the radiation and ventilation components of the model were evaluated separately. The uncalibrated model was found to systematically overestimate E0 with most of the model error being attributed to the ventilation component. Calibration of the radiation and ventilation components removed most of the systematic model errors, and the root mean square error for monthly mean E0 was 0.676 mm day-1 (16.8 percent of the mean observed value).

Hope, Allen S.; Evans, Shelly M.

1992-08-01

255

Packaging policies to reform the water sector: The case of the Central Valley Project Improvement Act  

NASA Astrophysics Data System (ADS)

Existing water policies often deviate from measures suggested by economic and environmental analysis. This is particularly true in the case of drought response policies, where effective policies are rarely adopted. This study focuses on how to enhance the political feasibility of options rather than identifying the optimal water policies. It argues that a legislative policy package may be a mechanism both to unite divergent interest groups into a coalition with common policy agendas and also to fragment or realign existing and traditional alliances. This majority building approach may have a greater chance of obtaining the required political support to advance water reforms. The negotiation over the Central Valley Project Improvement Act in California is used as an example. The case study illustrates how the policy packaging strategy split the traditional power alliance between the agricultural sector and the urban sector in California and between the agricultural sector in California and their allies in other U.S. western states. At the same time, policy packaging has created new regional and sectoral advocacy coalitions in support of water reform. As a result, the Bureau of Reclamation changed its policies in the Central Valley in California relating to the establishment of water markets, water pricing, and wildlife restoration fund and allocating water for the environment.

Fischhendler, Itay; Zilberman, David

2005-07-01

256

Recent land-use/land-cover change in the Central California Valley  

USGS Publications Warehouse

Open access to Landsat satellite data has enabled annual analyses of modern land-use and land-cover change (LULCC) for the Central California Valley ecoregion between 2005 and 2010. Our annual LULCC estimates capture landscape-level responses to water policy changes, climate, and economic instability. From 2005 to 2010, agriculture in the region fluctuated along with regulatory-driven changes in water allocation as well as persistent drought conditions. Grasslands and shrublands declined, while developed lands increased in former agricultural and grassland/shrublands. Development rates stagnated in 2007, coinciding with the onset of the historic foreclosure crisis in California and the global economic downturn. We utilized annual LULCC estimates to generate interval-based LULCC estimates (20002005 and 20052010) and extend existing 27 year interval-based land change monitoring through 2010. Resulting change data provides insights into the drivers of landscape change in the Central California Valley ecoregion and represents the first, continuous, 37 year mapping effort of its kind.

Soulard, Christopher E.; Wilson, Tamara S.

2013-01-01

257

A summary of ground-water pumpage in the Central Valley, California, 1961-77  

USGS Publications Warehouse

In the Central Valley of California, a great agricultural economy has been developed in a semiarid environment. This economy is supported by imported surface water and 9 to 15 million acre-feet per year of ground water. Estimates of ground-water pumpage computed from power consumption have been compiled and summarized. Under ideal conditions, the accuracy of the methods used is about 3 percent. This level of accuracy is not sustained over the entire study area. When pumpage for the entire area is mapped, the estimates seem to be consistent areally and through time. A multiple linear-regression model was used to synthesize data for the years 1961 through 1977, when power data were not available. The model used a relation between ground-water pumpage and climatic indexes to develop a full suite of pumpage data to be used as input to a digital ground-water model, one of the products of the Central Valley Aquifer Project. Statistical analysis of well-perforation data from drillers ' logs and water-temperature data was used to determine the percentage of pumpage that was withdrawn from each of two horizontal layers. (USGS)

Diamond, Jonathan; Williamson, A.K.

1983-01-01

258

Hydrogeologic framework and occurrence, movement, and chemical characterization of groundwater in Dixie Valley, west-central Nevada  

USGS Publications Warehouse

Dixie Valley, a primarily undeveloped basin in west-central Nevada, is being considered for groundwater exportation. Proposed pumping would occur from the basin-fill aquifer. In response to proposed exportation, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation and Churchill County, conducted a study to improve the understanding of groundwater resources in Dixie Valley. The objective of this report is to characterize the hydrogeologic framework, the occurrence and movement of groundwater, the general water quality of the basin-fill aquifer, and the potential mixing between basin-fill and geothermal aquifers in Dixie Valley. Various types of geologic, hydrologic, and geochemical data were compiled from previous studies and collected in support of this study. Hydrogeologic units in Dixie Valley were defined to characterize rocks and sediments with similar lithologies and hydraulic properties influencing groundwater flow. Hydraulic properties of the basin-fill deposits were characterized by transmissivity estimated from aquifer tests and specific-capacity tests. Groundwater-level measurements and hydrogeologic-unit data were combined to create a potentiometric surface map and to characterize groundwater occurrence and movement. Subsurface inflow from adjacent valleys into Dixie Valley through the basin-fill aquifer was evaluated using hydraulic gradients and Darcy flux computations. The chemical signature and groundwater quality of the Dixie Valley basin-fill aquifer, and potential mixing between basin-fill and geothermal aquifers, were evaluated using chemical data collected from wells and springs during the current study and from previous investigations. Dixie Valley is the terminus of the Dixie Valley flow system, which includes Pleasant, Jersey, Fairview, Stingaree, Cowkick, and Eastgate Valleys. The freshwater aquifer in the study area is composed of unconsolidated basin-fill deposits of Quaternary age. The basin-fill hydrogeologic unit can be several orders of magnitude more transmissive than surrounding and underlying consolidated rocks and Dixie Valley playa deposits. Transmissivity estimates in the basin fill throughout Dixie Valley ranged from 30 to 45,500 feet squared per day; however, a single transmissivity value of 0.1 foot squared per day was estimated for playa deposits. Groundwater generally flows from the mountain range uplands toward the central valley lowlands and eventually discharges near the playa edge. Potentiometric contours east and west of the playa indicate that groundwater is moving eastward from the Stillwater Range and westward from the Clan Alpine Mountains toward the playa. Similarly, groundwater flows from the southern and northern basin boundaries toward the basin center. Subsurface groundwater flow likely enters Dixie Valley from Fairview and Stingaree Valleys in the south and from Jersey and Pleasant Valleys in the north, but groundwater connections through basin-fill deposits were present only across the Fairview and Jersey Valley divides. Annual subsurface inflow from Fairview and Jersey Valleys ranges from 700 to 1,300 acre-feet per year and from 1,800 to 2,300 acre-feet per year, respectively. Groundwater flow between Dixie, Stingaree, and Pleasant Valleys could occur through less transmissive consolidated rocks, but only flow through basin fill was estimated in this study. Groundwater in the playa is distinct from the freshwater, basin-fill aquifer. Groundwater mixing between basin-fill and playa groundwater systems is physically limited by transmissivity contrasts of about four orders of magnitude. Total dissolved solids in playa deposit groundwater are nearly 440 times greater than total dissolved solids in the basin-fill groundwater. These distinctive physical and chemical flow restrictions indicate that groundwater interaction between the basin fill and playa sediments was minimal during this study period (water years 200911). Groundwater in Dixie Valley generally can be characterized as a sodium bicarbonate type, with greater proportions of chloride n

Huntington, Jena M.; Garcia, C. Amanda; Rosen, Michael R.

2014-01-01

259

Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California  

USGS Publications Warehouse

During the late Pleistocene, emergent groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (412 C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.011.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing of these fluctuations is consistent with changes in other paleowetland systems in the Mojave Desert, the nearby Great Basin Desert, and in southeastern Arizona, near the border of the Sonoran and Chihuahuan Deserts. The similarities in hydrologic conditions between these disparate locations suggest that changes in groundwater levels during the late Pleistocene in desert wetlands scattered throughout the American Southwest were likely driven by synoptic-scale climate processes.

Pigati, Jeffrey S.; Miller, David M.; Bright, Jordon E.; Mahan, Shannon A.; Nekola, Jeffrey C.; Paces, James B.

2011-01-01

260

Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California  

USGS Publications Warehouse

groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (4-12 ??C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.0-11.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing of these fluctuations is consistent with changes in other paleowetland systems in the Mojave Desert, the nearby Great Basin Desert, and in southeastern Arizona, near the border of the Sonoran and Chihuahuan Deserts. The similarities in hydrologic conditions between these disparate locations suggest that changes in groundwater levels during the late Pleistocene in desert wetlands scattered throughout the American Southwest were likely driven by synopticscale climate processes. ?? 2011 Geological Society of America.

Pigati, J.S.; Miller, D.M.; Bright, J.E.; Mahan, S.A.; Nekola, J.C.; Paces, J.B.

2011-01-01

261

[Ethnic conflicts and environmental degradation in Central Asia. The Ferghana valley and northern Kazakhstan].  

PubMed

This work seeks to demonstrate that the combination of ecological degradation, demographic pressure, and ethnic heterogeneity in Central Asia constitute a serious threat to the future stability of the region. The predominantly rural Ferghana Valley and Northern Kazakhstan suffer from shortages of water and land and from unemployment that leads to extensive out-migration to cities suffering from decline in their Soviet-era industries. The problem in the Ferghana Valley began with Tsarist conquest of the valley in 1876 and the subsequent imposition of cotton cultivation, which was greatly expanded by the Soviet Union. The Ferghana Valley, despite being a natural unit, was divided between Uzbekistan, Tajikistan, and Kyrgyzstan in the 1920s and 1930s, and remains divided between the independent states. The current population of 11 million is ethnically diverse, with Uzbeks in the majority and increasing most rapidly. Immigration from the Caucasus since 1950 added to the tension. Future peace will depend on such factors as whether the neo-Communist political regime chooses to incite ethnic hostilities, the manner in which land is redistributed, and the outcome of struggles for control of the flourishing narcotics trade. The northern Kazakhstan region was designated a pioneer wheat-growing region by Soviet planners in 1954. Russian and Ukrainian migrants established between 1954 and 1956 are today the predominant population sector, but feel their privileged position threatened by nationalist policies making Kazakh the official language and giving preference in employment to Kazakhs. Resettlement of Kazakhs from Mongolia, China, and Afghanistan in the region and the high Kazakh birth rate increase tensions. Grain production initially grew rapidly, but the mediocre soil and erosion-inducing constant dry winds have caused production to stagnate or decline. Regional disputes within Kazakhstan complicate the situation. Northern Kazakhstan, with its industrial development, is integrated more with the Urals and Western Siberia than with the rest of Kazakhstan. Serious ethnic conflicts in either Kazakhstan or the Ferghana Valley are likely to spill far beyond their local boundaries, embroiling much of the area in hostilities. PMID:12292788

De Cordier, B

1996-01-01

262

Chemistry, mineralogy and origin of the clay-hill nitrate deposits, Amargosa River valley, Death Valley region, California, U.S.A.  

USGS Publications Warehouse

The clay-hill nitrate deposits of the Amargosa River valley, California, are caliche-type accumulations of water-soluble saline minerals in clay-rich soils on saline lake beds of Miocene, Pliocene(?) and Pleistocene age. The soils have a maximum thickness of ??? 50 cm, and commonly consist of three layers: (1) an upper 5-10 cm of saline-free soil; (2) an underlying 15-20 cm of rubbly saline soil; and (3) a hard nitrate-rich caliche, 10-20 cm thick, at the bottom of the soil profile. The saline constituents, which make up as much as 50% of the caliche, are chiefly Cl-, NO-3, SO2-4 and Na+. In addition are minor amounts of K+, Mg2+ and Ca2+, varying, though generally minor, amounts of B2O3 and CO2-3, and trace amounts of I (probably as IO-3), NO-2, CrO2-4 and Mo (probably as MoO2-4). The water-soluble saline materials have an I/Br ratio of ??? 1, which is much higher than nearly all other saline depostis. The principal saline minerals of the caliche are halite (NaCl), nitratite (NaNO3), darapskite (Na3(SO4)(NO3)??H2O), glauberite (Na2Ca(SO4)2), gypsum (CaSO4??2H2O) and anhydrite (CaSO4). Borax (Na2B4O5(OH)4??8H2O), tincalconite (Na2B4O5(OH)4??3H2O) and trona (Na3(CO3)(HCO3)??2H2O) are abundant locally. The clay-hill nitrate deposits are analogous to the well-known Chilean nitrate deposits, and probably are of similar origin. Whereas the Chilean deposits are in permeable soils of the nearly rainless Atacama Desert, the clay-hill deposits are in relatively impervious clay-rich soils that inhibited leaching by rain water. The annual rainfall in the Death Valley region of ??? 5 cm is sufficient to leach water-soluble minerals from the more permeable soils. The clay-hill deposits contain saline materials from the lake beds beneath the nitrate deposits are well as wind-transported materials from nearby clay-hill soils, playas and salt marshes. The nitrate is probably of organic origin, consisting of atmospheric nitrogen fixed as protein by photoautotrophic blue-green algae, which are thought to form crusts on soils at the sites of the deposits when moistened by rainfall. The protein is subsequently transformed to nitrate by autotophic bacteria. ?? 1988.

Ericksen, G.E.; Hosterman, J.W.; St., Amand, P.

1988-01-01

263

Remediation of Mudboil Discharges in the Tully Valley of Central New York  

USGS Publications Warehouse

Mudboils have been documented in the Tully Valley in Onondaga County, in central New York State, since the late 1890s and have continuously discharged sediment-laden (turbid) water into nearby Onondaga Creek since the 1950s. The discharge of sediment causes gradual land-surface subsidence that, in the past, necessitated rerouting a major petroleum pipeline and a buried telephone cable, and caused two road bridges to collapse. The turbid water discharged from mudboils can be either fresh or brackish (salty). Mudboil activity was first reported in the Syracuse, NY, Post Standard in a short article dated October 19, 1899: 'Tully Valley - A Miniature Volcano Few people are aware of the existence of a volcano in this town. It is a small one, to be sure, but very interesting. In the 20-rod gorge where the crossroad leads by the Tully Valley grist mill the hard highway bed has been rising foot after foot till the apex of a cone which has been booming has broken open and quicksand and water flow down the miniature mountain sides. It is an ever increasing cone obliterating wagon tracks as soon as crossed. The nearby bluff is slowly sinking. Probably the highway must sometime be changed on account of the sand and water volcano, unless it ceases its eruption.' This newspaper article accurately describes mudboil activity and presages the collapse of the Otisco Road bridge, 92 years later in 1991. The article indicates that land subsidence occurred nearby, but gives no indication that Onondaga Creek was turbid; this was either an oversight by the reporter or was not a concern at that time.

Kappel, William M.

2009-01-01

264

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

265

Evaluating spatial and temporal variations of rainfall erosivity, case of Central Rift Valley of Ethiopia  

NASA Astrophysics Data System (ADS)

Land degradation in many Ethiopian highlands occurs mainly due to high rainfall erosivity and poor soil conservation practices. Rainfall erosivity is an indicator of the precipitation energy and ability to cause soil erosion. In Central Rift Valley (CRV) of Ethiopia, where the climate is characterized as arid and semiarid, rainfall is the main driver of soil erosion that in turn causes a serious expansion in land degradation. In order to evaluate the spatial and temporal variability of rainfall erosivity and its impact on soil erosion, long-term rainfall data (1980-2010) was used, and the monthly Fournier index (FI) and the annual modified Fournier index (MFI) were applied. Student's t test analysis was performed particularly to examine statistical significances of differences in average monthly and annual erosivity values. The result indicated that, in a similar spatial pattern with elevation and rainfall amount, average annual erosivity is also found being higher in western highlands of the valley and gradually decreased towards the east. The long-term average annual erosivity (MFI) showed a general decreasing trend in recent 10 years (2000-2010) as compared to previous 20 years (1980-1999). In most of the stations, average erosivity of main rainy months (May, June, July, and August) showed a decreasing trend, whereby some of them (about 33.3 %) are statically significant at 90 and 95 % confidence intervals but with high variation in spatial pattern of changes. The overall result of the study showed that rainfall aggression (erosivity) in the region has a general decreasing trend in the recent decade as compared to previous decades, especially in the western highlands of the valley. Hence, it implies that anthropogenic factors such as land use change being coupled with topography (steep slope) have largely contributed to increased soil erosion rate in the region.

Meshesha, Derege Tsegaye; Tsunekawa, Atsushi; Tsubo, Mitsuru; Haregeweyn, Nigussie; Adgo, Enyew

2015-02-01

266

Reconstruction of Flooding Events for the Central Valley, California from Instrumental and Documentary Weather Records  

NASA Astrophysics Data System (ADS)

All available instrumental winter precipitation data for the Central Valley of California back to 1850 were digitized and analyzed to construct continuous time series. Many of these data, in paper or microfilm format, extend prior to modern National Weather Service Cooperative Data Program and Historical Climate Network data, and were recorded by volunteer observers from networks such as the US Army Surgeon General, Smithsonian Institution, and US Army Signal Service. Given incomplete individual records temporally, detailed documentary data from newspapers, personal diaries and journals, ship logbooks, and weather enthusiasts instrumental data, were used in conjunction with instrumental data to reconstruct precipitation frequency per month and season, continuous days of precipitation, and to identify anomalous precipitation events. Multilinear regression techniques, using surrounding stations and the relationships between modern and historical records, bridge timeframes lacking data and provided homogeneous nature of time series. The metadata for each station was carefully screened, and notes were made about any possible changes to the instrumentation, location of instruments, or an untrained observer to verify that anomalous events were not recorded incorrectly. Precipitation in the Central Valley varies throughout the entire region, but waterways link the differing elevations and latitudes. This study integrates the individual station data with additional accounts of flood descriptions through unique newspaper and journal data. River heights and flood extent inundating cities, agricultural lands, and individual homes are often recorded within unique documentary sources, which add to the understanding of flood occurrence within this area. Comparisons were also made between dam and levee construction through time and how waters are diverted through cities in natural and anthropogenically changed environments. Some precipitation that lead to flooding events that occur in the Central Valley in the mid-19th century through the early 20th century are more outstanding at some particular stations than the modern records include. Several years that are included in the study are 1850, 1862, 1868, 1878, 1881, 1890, and 1907. These flood years were compared to the modern record and reconstructed through time series and maps. Incorporating the extent and effects these anomalous events in future climate studies could improve models and preparedness for the future floods.

Dodds, S. F.; Mock, C. J.

2009-12-01

267

Geomorphology and Tectonics at the Intersection of Silurian and Death Valleys, Southern California - 2005 Guidebook Pacific Cell Friends of the Pleistocene  

USGS Publications Warehouse

This publication describes results from new regional and detailed surficial geologic mapping, combined with geomorphologic, geochronologic, and tectonic studies, in Silurian Valley and Death Valley, California. The studies address a long-standing problem, the tectonic and geomorphic evolution of the intersection between three regional tectonic provinces: the eastern California shear zone, the Basin and Range region of southern Nevada and adjacent California, and the eastern Mojave Desert region. The chapters represent work presented on the 2005 Friends of the Pleistocene field trip and meeting as well as the field trip road log.

Miller, David M.; Valin, Zenon C.

2007-01-01

268

Petrologic Consequences of the Magmatic Death of a Continental Arc: Vanda Dike Swarm, Dry Valleys, Antarctica  

NASA Astrophysics Data System (ADS)

The Dry Valleys of southern Victoria Land, Antarctica, are notable for the presence of the Vanda dikes, prominent NE-trending swarms that crosscut a sequence of granitoid plutons. These older plutons are regional in extent and comprise 3 Cambro-Ordovician groups, including: a) calc-alkaline granitoids formed at an active plate margin during the Ross Orogeny (c. 505 Ma); b) adakitic granitoids, likely marking the conclusion of Ross Orogeny subduction-related activity (c. 490 Ma); and c) younger monzonitic plutons, probably generated in an intraplate extensional setting (Cox et al., 2000). The Vanda dikes crosscut the younger plutons, possibly between c. 490 and 477 Ma (Allibone et al., 1993; Encarnacion and Grunow, 1996). Dikes from the east wall of Bull Pass and the south wall of the Wright Valley range from 0.5-25 m wide with nearly vertical dips, are usually several km long, and, in the center of the swarms, occur with a frequency of ~18 dikes/km. Most have chilled margins and are surrounded by brittle fractures, indicative of shallow intrusion into cold country rock. Dike compositions are bimodal, most defining a trend at the boundary between the high-K calc-alkaline and shoshonite series in SiO2-K2O space; some Wright Valley dikes have slightly lower K2O and are calc-alkaline. Granite porphyry dikes are relatively homogeneous (69-73 wt.% SiO2), whereas the mafic dikes exhibit a wider range of compositions (49-57 wt.% SiO2). The felsic and mafic dikes have distinct trace element abundances but similar normalized distribution patterns, including fractionated heavy rare earth elements and negative Eu and high field-strength element anomalies. Average Sr/Y ratios of both the felsic and mafic dikes cluster around 20, well below a typical adakite signature. Major and trace element variations suggest that the felsic dikes may be differentiates of the mafic magmas. Field relations further indicate that the felsic lavas may represent, on average, a later phase of dike intrusion (Keiller, 1988; Allibone et al., 1993). The high-K calc-alkaline Vanda dike swarm likely represents the last phase of magmatism in a dying continental arc, perhaps accompanied by extension and uplift of the orogen. The relatively alkaline compositions of the dikes may result from lower degrees of melting, as subduction waned. References: Allibone, AH et al., New Zealand J of Geology and Geophysics, 36: 281-297, 1993. Cox, SC et al., New Zealand J of Geology and Geophysics, 43: 501-520, 2000. Encarnacion, J and Grunow, A, Tectonics, 15: 1325-1341, 1996. Keiller, IG, New Zealand Antarctic Record, 8: 25-34, 1988.

Harpp, K. S.; Christensen, B. C.; Geist, D. J.; Garcia, M. O.

2005-12-01

269

Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model  

USGS Publications Warehouse

A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional ground-water flow system. Ground-water flow in the Death Valley region is composed of several interconnected, complex ground-water flow systems. Ground-water flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional ground-water flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and evapotranspiration (ET) are the dominant natural ground-water discharge processes. Ground water also is withdrawn for agricultural, commercial, and domestic uses. Ground-water flow in the DVRFS was simulated using MODFLOW-2000, a 3D finite-difference modular ground-water flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 m on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins, also simulated by drains. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient model gener

: Belcher, Wayne R., (Edited By)

2004-01-01

270

Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model  

USGS Publications Warehouse

A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided by acquiring additional data, by reevaluating existing data using current technology and concepts, and by refining earlier interpretations to reflect the current understanding of the regional groundwater flow system. Groundwater flow in the Death Valley region is composed of several interconnected, complex groundwater flow systems. Groundwater flow occurs in three subregions in relatively shallow and localized flow paths that are superimposed on deeper, regional flow paths. Regional groundwater flow is predominantly through a thick Paleozoic carbonate rock sequence affected by complex geologic structures from regional faulting and fracturing that can enhance or impede flow. Spring flow and ET are the dominant natural groundwater discharge processes. Groundwater also is withdrawn for agricultural, commercial, and domestic uses. Groundwater flow in the DVRFS was simulated using MODFLOW-2000, the U.S. Geological Survey 3D finitedifference modular groundwater flow modeling code that incorporates a nonlinear least-squares regression technique to estimate aquifer parameters. The DVRFS model has 16 layers of defined thickness, a finite-difference grid consisting of 194 rows and 160 columns, and uniform cells 1,500 meters (m) on each side. Prepumping conditions (before 1913) were used as the initial conditions for the transient-state calibration. The model uses annual stress periods with discrete recharge and discharge components. Recharge occurs mostly from infiltration of precipitation and runoff on high mountain ranges and from a small amount of underflow from adjacent basins. Discharge occurs primarily through ET and spring discharge (both simulated as drains) and water withdrawal by pumping and, to a lesser amount, by underflow to adjacent basins simulated by constant-head boundaries. All parameter values estimated by the regression are reasonable and within the range of expected values. The simulated hydraulic heads of the final calibrated transient mode

: Belcher, Wayne R., (Edited By); Sweetkind, Donald S.

2010-01-01

271

Using the Bidirectional Reflectance Distribution Function (BRDF) for remotely mapping surface roughness on alluvial fans: A comparison of Death Valley, CA to Mojave Crater on Mars  

NASA Astrophysics Data System (ADS)

The Bidirectional Reflectance Distribution Function (BRDF) describes how incoming light from a given direction is reflected from specific surfaces in response to different incoming solar radiation angles. The amount and directionality of reflected light is a function of surface roughness and orientation. The goal of this study is to assess whether a BRDF based approach may be applicable for creating surface roughness maps for Martian alluvial fans. Landsat 7 satellite imagery is used to make classifications of surfaces with different roughness and spectral properties for alluvial fan surfaces in Death Valley, California. The resulting classes have been interpreted to represent surfaces of different ages and also different deposit types. In Death Valley, older surfaces are classified based on the amount of shadowing due to gully formation, differences in the amount of surface smoothness from desert pavement formation, and desert varnish color variations. In contrast, the most recently formed surfaces have an assemblage of classes that represent surface deposits of different grain size and sorting, as well as different landform types - incised channels and elevated bars. Many Death Valley fans have a telescoping morphology where progressively younger surfaces reach basin-ward. This is more evident on some fans using a BRDF classification. A similar map was made for depositional landforms within Mojave Crater on Mars, identified as sub-kilometer alluvial fans by Williams and Malin (2008). These alluvial fans are the youngest found on Mars (Amazonian age) and have topographic similarities to fans in the southwestern US. Any geomorphic similarities between Death Valley fans and those within Mojave Crater can be assessed using surface roughness. Imagery from both the High Resolution Imaging Experiment (HiRISE) and Context Camera (CTX) onboard the Mars Reconnaissance Orbiter (MRO) were used to compare differences in spatial resolution on BRDF classifications. The resulting surface roughness maps are strikingly similar in classes and patterns to many fans within Death Valley. The surfaces interpreted by Williams and Malin (2008) to be evidence of multiple flow events are clearly classified using BRDF. In addition to age differences, possible locations of materials with different grain size and sorting are also identified. Since the BRDF classes of certain surface features on Earth and Mars fans largely overlap, field observations for each class type made for Death Valley fan surfaces may be useful for understanding the past fluvial processes on Mars and their similarities with fan forming processes in arid regions on Earth. This remote sensing approach has the potential to provide a tool for studying fans that may be inaccessible or too large for extensive fieldwork.

Doyle, S. L.; Wilkinson, M. J.; Scuderi, L. A.; Weissmann, G. S.; Scuderi, L. J.

2011-12-01

272

Buried paleoindian-age landscapes in stream valleys of the central plains, USA  

USGS Publications Warehouse

A systematic study of late-Quaternary landscape evolution in the Central Plains documented widespread, deeply buried paleosols that represent Paleoindian-age landscapes in terrace fills of large streams (> 5th order), in alluvial fans, and in draws in areas of western Kansas with a thick loess mantle. Alluvial stratigraphic sections were investigated along a steep bio-climatic gradient extending from the moist-subhumid forest-prairie border of the east-central Plains to the dry-subhumid and semi-arid shortgrass prairie of the west-central Plains. Radiocarbon ages indicate that most large streams were characterized by slow aggradation accompanied by cumulic soil development from ca. 11,500 to 10,000??14C yr B.P. In the valleys of some large streams, such as the Ninnescah and Saline rivers, these processes continued into the early Holocene. The soil-stratigraphic record in the draws of western Kansas indicates slow aggradation punctuated by episodes of landscape stability and pedogenesis beginning as early as ca. 13,300??14C yr B.P. and spanning the Pleistocene-Holocene boundary. The development record of alluvial fans in western Kansas is similar to the record in the draws; slow aggradation was punctuated by multiple episodes of soil development between ca. 13,000 and 9000??14C yr B.P. In eastern Kansas and Nebraska, development of alluvial fans was common during the early and middle Holocene, but evidence shows fan development as early as ca. 11,300??14C yr B.P. Buried soils dating between ca. 12,600 and 9000??14C yr B.P. were documented in fans throughout the region. In stream valleys across the Central Plains, rapid alluviation after ca. 9000??14C yr B.P. resulted in deeply buried soils that may harbor Paleoindian cultural deposits. Hence, the paucity of recorded stratified Paleoindian sites in the Central Plains is probably related to poor visibility (i.e., deep burial in alluvial deposits) instead of limited human occupation in the region during the terminal Pleistocene and early Holocene. The thick, dark, cumulic A horizons of soils, representing buried Paleoindian-age landscapes, are targets for future archaeological surveys. ?? 2008 Elsevier B.V. All rights reserved.

Mandel, R.D.

2008-01-01

273

Community health centers: a promising venue for supplemental nutrition assistance program education in the Central Valley.  

PubMed

Health care providers could help achieve the necessary shift to healthful eating and active living; however, lack of coverage or reimbursement, lack of time, and limited information about appropriate interventions are some of the documented barriers. This report highlights the potential for Supplemental Nutrition Assistance Program Education (SNAP-Ed) implementation in the relatively nontraditional setting of Federally Qualified Health Centers based on the experience of the Central Valley Health Network's Nutrition Education Demonstration Project. The report provides a brief overview of the primary prevention role(s) suggested for health care providers, relevant SNAP-Ed policies, how SNAP-Ed has been implemented in Federally Qualified Health Center settings, and recommendations for similar efforts. PMID:21683283

MkNelly, Barbara; Nishio, Stephanie; Peshek, Cynthia; Oppen, Michelle

2011-01-01

274

Comparison of Summer and Winter California Central Valley Aerosol Distributions from Lidar and MODIS Measurements  

NASA Technical Reports Server (NTRS)

Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2008. While the PM2.5 concentration is highest in the winter, the aerosol optical depth measured from MODIS is highest in the summer. A seasonal comparison shows that PM2.5 in the winter can exceed summer PM2.5 by 55%, while summer AOD exceeds winter AOD by 43%. Higher temperatures wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not surface particulate matter monitors. Measurements of the boundary layer height from lidar instruments are necessary to incorporate satellite measurements with air quality measurements.

Lewis, Jasper R., Jr.; DeYoung, Russell J.; Chu, D. Allen

2010-01-01

275

Analysis of microsatellite DNA resolves genetic structure and diversity of chinook salmon ( Oncorhynchus tshawytscha ) in California's Central Valley  

Microsoft Academic Search

We use 10 microsatellite DNA markers to assess genetic diversity within and among the four runs (winter, spring, fall, and late fall) of chinook salmon ( Oncorhynchus tshawytscha ) in California's Central Valley. Forty-one pop- ulation samples are studied, comprising naturally spawning and hatchery stocks collected from 1991 through 1997. Maximum likelihood methods are used to correct for kinship in

Michael A. Banks; Vanessa K. Rashbrook; Marco J. Calavetta; Cheryl A. Dean; Dennis Hedgecock

2000-01-01

276

Paleohydrological fluctuations and steppe vegetation during the last glacial maximum in the central Ebro valley (NE Spain)  

Microsoft Academic Search

Combined analysis of sedimentary facies, geochemistry and pollen from lake sediment records, and sedimentological and palynological studies from slope deposits allow the characterization of vegetation and lake level status during the Last Glacial (LGM) in the central Ebro valley (NE Spain). These records show the presence of phases of increased effective moisture, while regional vegetation was dominated by steppe species.

Blas L. Valero-Garcs; Penlope Gonzlez-Sampriz; Ana Navas; Javier Mach??n; Antonio Delgado-Huertas; Jose Luis Pea-Monn; Carlos Sancho-Marcn; Tony Stevenson; Basil Davis

2004-01-01

277

Use of Otolith Microstructure to Discriminate Stocks of Juvenile Central Valley, California, Fall-Run Chinook Salmon  

Microsoft Academic Search

We examined the utility of otolith microstructure analysis as a means of discriminating among stocks and between rearing types of juvenile fall-run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley. Otolith samples were collected from 11 geographically discrete stocks of fall-run Chinook salmon of river and hatchery rearing types over 2 years. Six measured otolith attributes and three statistics derived

Martha C. Volkoff; Robert G. Titus

2007-01-01

278

Late quaternary geomorphology and geoarchaeology of a segment of the Central Mimbres River Valley, Grant County, New Mexico  

E-print Network

Two terraces, a modem floodplain, and alluvial fans were identified along a segment of the central Mimbres River Valley in Grant County, New Mexico. The oldest terrace, T2, is composed of one major depositional unit (1) and is capped by a...

Fitch, Michael Anthony

1996-01-01

279

Fluid inclusion and ReOs isotopic evidence for hot, Cenozoic mineralization in the central Pennsylvanian Valley and Ridge Province  

Microsoft Academic Search

SummaryHypotheses concerning processes and timing of hydrothermal sulfide mineralization in the central Pennsylvanian Appalachians\\u000a utilize Mississippi Valley-type (MVT) models with Paleozoic ages. To examine this model, we studied sulfide-bearing veins\\u000a in the Skytop sulfide occurrence that contain pyritecentral Pennsylvania, USA. In this study,\\u000a we obtained ReOs isotope compositions of hydrothermal pyrite and fluid inclusion data from

R. Mathur; L. Mutti; F. Barra; D. Gold; R. C. Smith; A. Doden; T. Detrie; J. Ruiz; A. McWilliams

2008-01-01

280

Lake Sediment Records of Holocene Climate Change in the Khanuy Valley, Arkhangai Aimag, North-Central Mongolia  

Microsoft Academic Search

Late Holocene geochemical records from three lakes in the Khanuy Valley, Arkhangai Aimag, north-central Mongolia document centennial and millennial-scale climate variability within central Asia. The oldest sediments of the shallow Tsegeen Nuur basin (49.09N, 101.86E) and nearby Sharga Nuur (48.92N, 101.96E) indicate lake filling and open water deposition by at least 3600 years before present (yrs. B.P.). Minimum oxygen isotope

S. E. Strano; M. F. Rosenmeier; S. Nergui

2006-01-01

281

Knowledge, transparency, and refutability in groundwater models, an example from the Death Valley regional groundwater flow system  

NASA Astrophysics Data System (ADS)

This work demonstrates how available knowledge can be used to build more transparent and refutable computer models of groundwater systems. The Death Valley regional groundwater flow system, which surrounds a proposed site for a high level nuclear waste repository of the United States of America, and the Nevada National Security Site (NNSS), where nuclear weapons were tested, is used to explore model adequacy, identify parameters important to (and informed by) observations, and identify existing old and potential new observations important to predictions. Model development is pursued using a set of fundamental questions addressed with carefully designed metrics. Critical methods include using a hydrogeologic model, managing model nonlinearity by designing models that are robust while maintaining realism, using error-based weighting to combine disparate types of data, and identifying important and unimportant parameters and observations and optimizing parameter values with computationally frugal schemes. The frugal schemes employed in this study require relatively few (10-1000 s), parallelizable model runs. This is beneficial because models able to approximate the complex site geology defensibly tend to have high computational cost. The issue of model defensibility is particularly important given the contentious political issues involved.

Hill, Mary C.; Faunt, Claudia C.; Belcher, Wayne R.; Sweetkind, Donald S.; Tiedeman, Claire R.; Kavetski, Dmitri

282

Evaluation of increases in dissolved solids in ground water, Stovepipe Wells Hotel, Death Valley National Monument, California  

USGS Publications Warehouse

Increases in dissolved solids have been monitored in two observation wells near Stovepipe Wells Hotel, Death Valley National Monument, California. One of the hotel 's supply wells delivers water to a reverse-osmosis treatment plant that produces the area 's potable water supply. Should water with increased dissolved solids reach the supply well, the costs of production of potable water will increase. The reverse-osmosis plant supply well is located about 0.4 mile south of one of the wells where increases have been monitored, and 0.8 mile southwest of the well where the most significant increases have been monitored. The direction of local ground-water movement is eastward, which reduces the probability of the supply well being affected. Honey mesquite, a phreatophyte located about 1.5 miles downgradient from the well where the most significant increases have been monitored, might be adversely affected should water with increased dissolved solids extend that far. Available data and data collected during this investigation do not indicate the source of the dissolved-solids increases. Continued ground-water-quality monitoring of existing wells and the installation of additional wells for water-quality monitoring would be necessary before the area affected by the increases, and the source and direction of movement of the water with increased dissolved solids, can be determined. (USGS)

Buono, Anthony; Packard, E.M.

1982-01-01

283

Sliding stones of Racetrack Playa, Death Valley, USA: The roles of rock thermal conductivity and fluctuating water levels  

NASA Astrophysics Data System (ADS)

On occasion, Racetrack playa in Death Valley National Park becomes flooded and temperatures then drop appreciably below freezing. The thermal conductivity of rock is greater than that of water, so heat is conducted from a partially-submerged rock faster than from water. Consequently, a collar of thicker ice forms at the water surface, a layer of ice forms on more deeply-submerged parts of the rock, and playa sediment beneath the rock may even become frozen to it. While this occurs, only a surface layer of ice forms on water away from the rock. Once the ice becomes thick enough, perhaps only 5-10 mm, either the buoyancy of the ice or additions of water to the playa by rain, snow-melt, or groundwater seepage then reduce the normal force between the rock and the playa to the point where wind shear can move the ice sheet with its entrained rocks, making trails (Stanley, 1955; Reid et al., 1995). After the ice melts, rocks are left at the ends of the trails, sometimes atop a pedestal of silt. A renewed increase in water level on the playa before the ice melts may lift a rock completely free of the playa surface and whisk it away, leaving a rockless trail. During a movement event, changes in rock orientation or water depth may result in changes in width along the track. Rock speeds are likely tens to hundreds of millimeters per second.

Kletetschka, Gunther; Hooke, Roger LeB.; Ryan, Andrew; Fercana, George; McKinney, Emerald; Schwebler, Kristopher P.

2013-08-01

284

Assessment of Computer-based Geologic Mapping of Rock Units in the LANDSAT-4 Scene of Northern Death Valley, California  

NASA Technical Reports Server (NTRS)

Geologists obtain low accuracy levels when maps derived from LANDSAT MSS data are compared with those made by conventional methods. Procedures developed for the IDIMS computer system and used to classify a subset of a TM image of the Death Valley, California - Nevada border are described. Despite the superior resolution, broader spectral coverage, and greater sensitivity inherent to the TM, the actual recorded measured accuracy was in the same narrow range (30 to 60%) recorded for MSS data from earlier LANDSATs. The supervised classification approach appears to be superior to the unsupervised approach when applied to vegetation-sparse surfaces composed of spectrally contrasting rock/soil units distributed in relatively flat to low relief terrain. As spatial resolution improves and optimal spectral bands for identifying rock materials are specified, use of classified multispectral remote sensing data from air and space when coupled with supporting field calibration and checks should become the dominant way in which geologic mapping is carried out in future decades.

Short, N. M.

1985-01-01

285

Isolation and characterization of two serine proteases from metagenomic libraries of the Gobi and Death Valley deserts.  

PubMed

The screening of environmental DNA metagenome libraries for functional activities can provide an important source of new molecules and enzymes. In this study, we identified 17 potential protease-producing clones from two metagenomic libraries derived from samples of surface sand from the Gobi and Death Valley deserts. Two of the proteases, DV1 and M30, were purified and biochemically examined. These two proteases displayed a molecular mass of 41.5 kDa and 45.7 kDa, respectively, on SDS polyacrylamide gels. Alignments with known protease sequences showed less than 55% amino acid sequence identity. These two serine proteases appear to belong to the subtilisin (S8A) family and displayed several unique biochemical properties. Protease DV1 had an optimum pH of 8 and an optimal activity at 55C, while protease M30 had an optimum pH >11 and optimal activity at 40C. The properties of these enzymes make them potentially useful for biotechnological applications and again demonstrate that metagenomic approaches can be useful, especially when coupled with the study of novel environments such as deserts. PMID:21494865

Neveu, Julie; Regeard, Christophe; DuBow, Michael S

2011-08-01

286

Delineation and hydrologic effects of a gasoline leak at Stovepipe Wells Hotel, Death Valley National Monument, California  

USGS Publications Warehouse

Ground water is the only local source of water available to the Stovepipe Wells Hotel facilities of the Death Valley National Monument, California. A leak in a service station storage tank caused the formation of a gasoline layer overlying the water table, creating the potential for contamination of the water supply. The maximum horizontal extent of the gasoline layer was mathematically estimated to be 1,300 feet downgradient from the leaky gasoline tank. Exploratory drilling detected the gasoline layer between 900 and 1,400 feet downgradient and between 50 and 150 feet upgradient from the source. Traces of the soluble components of gasoline were also found in the aquifer 150 feet upgradient, and 250 feet distant from the source perpendicular to the direction of ground-water movement. The gasoline spill is not likely to have an effect on the supply wells located 0.4 mile south of the leak source, which is nearly perpendicular to the direction of ground-water movement and the primary direction of gasoline movement in the area. No effect on phreatophytes 2 miles downgradient from the layer is likely, but the potential effects of gasoline vapors within the unsaturated zone on local xerophytes are not known. (USGS)

Buono, A.; Packard, Elaine M.

1982-01-01

287

Simulated effects of climate change on the Death Valley regional ground-water flow system, Nevada and California  

SciTech Connect

The US Geological Survey, in cooperation with the US Department of Energy, is evaluating the geologic and hydrologic characteristics of the Death Valley regional flow system as part of the Yucca Mountain Project. As part of the hydrologic investigation, regional, three-dimensional conceptual and numerical ground-water-flow models have been developed to assess the potential effects of past and future climates on the regional flow system. A simulation that is based on climatic conditions 21,000 years ago was evaluated by comparing the simulated results to observation of paleodischarge sites. Following acceptable simulation of a past climate, a possible future ground-water-flow system, with climatic conditions that represent a doubling of atmospheric carbon dioxide, was simulated. The steady-state simulations were based on the present-day, steady-state, regional ground-water-flow model. The finite-difference model consisted of 163 rows, 153 columns, and 3 layers and was simulated using MODFLOWP. Climate changes were implemented in the regional ground-water-flow model by changing the distribution of ground-water recharge. Global-scale, average-annual, simulated precipitation for both past- and future-climate conditions developed elsewhere were resampled to the model-grid resolution. A polynomial function that represents the Maxey-Eakin method for estimating recharge from precipitation was used to develop recharge distributions for simulation.

D`Agnese, F.A.; O`Brien, G.M.; Faunt, C.C.; San Juan, C.A.

1999-04-01

288

Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California  

SciTech Connect

Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35{degrees}N., long 115{degrees}W and lat 38{degrees}N., long 118{degrees}W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system.

D`Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

1997-12-31

289

Data on ground-water quality for the western Nevada part of the Death Valley 1 degree by 2 degree quadrangle  

USGS Publications Warehouse

Water quality data for groundwater has been compiled for the Nevada part of the Death Valley 1 degree x 2 degree quadrangle which covers a portion of western Nevada. Chemical characteristics of the water are shown on a map (at a scale of 1:250,000) and on trilinear diagrams for the major ions. The data for the area are also presented in a table. (USGS)

Welch, Alan H.; Williams, Rhea P.

1987-01-01

290

Tilt and rotation of the footwall of a major normal fault system: Paleomagnetism of the Black Mountains, Death Valley extended terrane, California  

Microsoft Academic Search

Paleomagnetic data have been obtained from Miocene intrusions, Proterozoic Paleomagnetic data have been obtained from Miocene intrusions, Proterozoic crystalline rocks and cross-cutting mafic to felsic dikes to evaluate footwall deformation during extension and unroofing of the crystalline core of the Black Mountains, Death Valley, California. Synrift intrusions contain a well-defined and, at the site level, well-grouped magnetization, interpreted to be

DANIEL K. HOLM; JOHN W. GEISSMAN; BRIAN WERNICKE

1993-01-01

291

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

USGS Publications Warehouse

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 results indicate that although WRP in the CCV and UKRB provide a number of benefits, there may be management mediated trade-offs among ecosystem services. In this report, we considered ecosystem services at the site-specific scale; however, future work will extend to include effects of WRP relative to surrounding cropland.

2011-01-01

292

Sedimentology and progressive tectonic unconformities of the sheetflood-dominated Hell's Gate alluvial fan, Death Valley, California  

NASA Astrophysics Data System (ADS)

The Hell's Gate alluvial fan of northern Death Valley has an area of 49.5 km 2, a radius of 11.8 km, and a smooth 5-3 sloping surface interrupted by shallow (<0.5 m), radially aligned gullies 1-4 m wide. Facies analysis of 1-14 m high exposures at 45 sites reveals that the fan is built almost entirely by water-flow processes. Two facies deposited by sheetflooding dominate the exposures from apex to toe. The main one (Facies A), comprising 80-95% of the cuts, consists of sandy, granular, fine to medium pebble gravel that alternates with cobbly, coarse to very coarse pebble gravel in planar-stratified couplets 5-20 cm thick that are aligned parallel to the fan surface. Facies B, comprising 0-10% of the exposures, consists of 10-40 cm thick wedge-planar beds of sandy pebble gravel in backsets dipping 5 to 24. Both Facies A and B are produced by infrequent sediment-charged flash floods from the catchment, and accumulate on the fan from supercritical standing waves of an expanding sheetflood. Antidune backsets are deposited during the buildup stage of the standing-wave cycle, and the couplets during the washout stage. The autocyclic growth and destruction of standing waves during a single sheetflood produces 50-250 cm thick sequences of multiple couplets with backsets. Couplets prevail over antidunes due to the selective preservation of deposits of the standing wave washout phase. Three minor facies comprise 5-20% of the fan exposures. The most common one (Facies D) is pebbly cobble gravel in lenticular beds typically 5-25 cm thick that overlie erosional scours into sheetflood deposits. It comprises gravel concentrated in gullies by fine-fraction winnowing of sheetflood units during recessional flood or by secondary overland flows. Though common on the fan surface, this facies is stratigraphically limited. Facies C consists of medium- to very fine-grained eolian sandsheet deposits 5-30 cm thick present on the distal fan in association with gully-fill gravel. It forms by wind reworking of the fan surface, and by sand transport from the adjoining erg. Facies C and D gully-fill and eolian deposits together comprise bounding beds that divide successive sheetflood sequences. They record secondary processes active on the surface between infrequent sheetfloods that mainly aggrade the fan. The fifth fan facies (Facies E) consists of lakeshore gravel deposited along the distal fan when it was transgressed by Lake Manly during latest Pleistocene time. The medial 3.8 km part of the Hell's Gate fan is uplifted and backtilted 1 to 16 into a tectonic ridge formed during strike-slip motion along the North Death Valley fault. Progressive intrafan unconformities, each likely initiated during one large earthquake, are common in these deposits. Two to eight sheetflood units capped by gully-fill or eolian facies are exposed within unconformity-bounded intervals, indicating that fan-aggrading catastrophic sheetfloods on a given part of fan are 2 to ?8 times more frequent than earthquakes that cause backtilting.

Blair, T. C.

2000-05-01

293

Mg- and K-bearing borates and associated evaporites at Eagle Borax spring, Death Valley, California: A spectroscopic exploration  

USGS Publications Warehouse

Efflorescent crusts at the Eagle Borax spring in Death Valley, California, contain an array of rare Mg and K borate minerals, several of which are only known from one or two other localities. The Mg- and/or K-bearing borates include aristarainite, hydroboracite, kaliborite, mcallisterite, pinnoite, rivadavite, and santite. Ulexite and probertite also occur in the area, although their distribution is different from that of the Mg and K borates. Other evaporite minerals in the spring vicinity include halite, thenardite, eugsterite, gypsum-anhydrite, hexahydrite, and bloedite. Whereas the first five of these minerals are found throughout Death Valley, the last two Mg sulfates are more restricted in occurrence and are indicative of Mg-enriched ground water. Mineral associations observed at the Eagle Borax spring, and at many other borate deposits worldwide, can be explained by the chemical fractionation of borate-precipitating waters during the course of evaporative concentration. The Mg sulfate and Mg borate minerals in the Eagle Borax efflorescent crusts point to the fractionation of Ca by the operation of a chemical divide involving Ca carbonate and Na-Ca borate precipitation in the subsurface sediments. At many other borate mining localities, the occurrence of ulexite in both Na borate (borax-kernite) and Ca borate (ulexite-colemanite) deposits similarly reflects ulexite's coprecipitation with Ca carbonate at an early concentration stage. Such ulexite may perhaps be converted to colemanite by later reaction with the coexisting Ca carbonate - the latter providing the additional Ca2+ ions needed for the conversion. Mg and Ca-Mg borates are the expected late-stage concentration products of waters forming ulexite-colemanite deposits and are therefore most likely to occur in the marginal zones or nearby mud facies of ulexite-colemanite orebodies. Under some circumstances, Mg and Ca-Mg borates might provide a useful prospecting guide for ulexite-colemanite deposits, although the high solubility of Mg borate minerals may prevent their formation in lacustrine settings and certainly inhibits their geologic preservation. The occurrence of Mg borates in borax-kernite deposits is also related to fractionation processes and points to the operation of an Mg borate chemical divide, characterized by Mg borate precipitation ahead of Mg carbonate. All of these considerations imply that Mg is a significant chemical component of many borate-depositing ground waters, even though Mg borate minerals may not be strongly evident in borate orebodies. The Eagle Borax spring borates and other evaporite minerals were studied using spectroscopic and X-ray powder diffraction methods, which were found to be highly complementary. Spectral reflectance measurements provide a sensitive means for detecting borates present in mixtures with other evaporites and can be used to screen samples rapidly for X-ray diffraction analysis. The apparently limited occurrence of Mg and K borate minerals compared to Ca and Na borates may stem partly from the inefficiency of X-ray diffraction methods for delineating the mineralogy of large and complex deposits. Spectral reflectance measurements can be made in the laboratory, in the field, on the mine face, and even remotely. Reflectance data should have an important role in studies of existing deposit mineralogy and related chemical fractionation processes, and perhaps in the discovery of new borate mineral resources.

Crowley, J.K.

1996-01-01

294

Impacts of Discharge Reductions on Physical and Thermal Habitat Characteristics in a Desert Spring, Death Valley National Park, California, USA  

NASA Astrophysics Data System (ADS)

Desert springs are biodiversity hotspots that are sensitive to anthropogenic activities. Despite their importance, the effects of human disturbance on desert springs are not well known, and scarce information exists describing the biotic or environmental effects of incrementally increasing disturbance. The objective of this research was to quantify the influence of incremental reductions in discharge on the physical and thermal characteristics of a desert springbrook. This objective was accomplished through a combination of field experiments at Travertine Spring in Death Valley National Park, USA, and hydraulic/temperature modeling in order to: (1) quantify changes in physical characteristics of the springbrook channel and aquatic environment; (2) investigate the effects of reduced spring discharge on seasonal spatial temperature patterns; (3) delineate tipping points that exhibit a non-linear response to decreased flow. The study results supported our predictions that decreased discharge would modify physical habitat characteristics of the springbrook, reduce aquatic habitat volume, increase variability in water temperatures along the springbrook, and reduce springbrook suitability for invertebrates that require stable environments. Field observations revealed a significant relationship between water depth and flow velocity with reduced spring discharge. The rate of change of mean water depths, velocities, and habitat volumes were greatest with only a 10% reduction in spring flow. In addition, a non-linear temperature response to flow reductions was present under all modeled conditions. Generally, water temperature gradients increased as flows were decreased, and the sensitivity of reduced discharge increased with distance from the spring source. The degree of sensitivity was a function of season, which reflects the influence of ambient air temperature and wind in the cooling of the springbrook. These results suggest that habitat for species using stable thermal environments will decrease, and habitat for species adapted to variable environments will increase.

Morrison, R. R.; Stone, M. C.; Sada, D. W.

2013-12-01

295

Evidence for a Putative Impact Structure in Palm Valley, Central Australia  

NASA Astrophysics Data System (ADS)

Introduction: We present evidence supporting the impact origin of a circular structure located in Palm Valley, Central Australia (24 03' 06'' S, 132 42' 34'' E). The ~280 m wide structure was discovered using a combination of Google Maps and a local Arrernte Aboriginal oral tradition regarding a star that fell into a waterhole called Puka in Palm Valley, Northern Territory [1][2] (see [3] for details of the discovery). Geophysical Evidence: A survey of the structure in September 2009 collected magnetic, gravity and topographic data. Geophysical modeling of the data revealed the structure has a bowl-shaped subsurface morphology, as expected for a simple impact crater. Though the structure sits within the Finke Gorge system, the models do not support an erosional origin for the structure, as no buried channels are observed. Nor does the modeling fit a volcanic origin, as the density structure at depth is consistent with fractured sandstone/sediments. Geological Evidence: One channel runs out of the crater to the south, consistent with outflow from crater-filling events, but again not with an erosional origin for the structure itself. The microstructure of rock samples collected from the site revealed the presence of planar deformation features in the quartz grains. The coincident angle of the fractures is consistent with the crystallographic fracture directions under mild-end shocks. These grains probably represent local focusing of stress as the shock wave moved through the heterogeneous grain matrix, suggesting the conditions were right for the shock pressure to locally exceed the ~7.5 GPa required to form the features, even though the bulk of the shock pressure was much less. Conclusion: Based on the level of erosion and the absence of shatter cones and meteorite fragments, we estimate the structure's age to be in the millions of years. While the presence of shocked-quartz is a direct indicator of a cosmic impact, we cannot rule out that the quartz was transported from an older structure into the Hermannsburg sandstone as it was deposited. The ~22 km wide Gosse's Bluff impact structure, located ~40 km from Palm Valley, postdates the Hermannsburg sandstone, leaving a distal unidentified impact event as a possibility. However, the bowl shaped morphology of the Palm Valley structure, as well as the fractures on the structure's walls, support an impact origin. References: [1] Austin-Broos, D., 2009, "Arrernte Past, Arrernte Present", University of Chicago Press, pp. 37-38. [2] Rheim, G., 1945, "The Eternal Ones of the Dream: a psychoanalytic interpretation of Australian myth and ritual", International Universities Press, New York, p. 183. [3] Hamacher, D.W. & Norris, R.P., 2010, Using Aboriginal Oral Traditions to locate meteorite falls and impact craters. In Ilgarijiri - things belonging to the sky, edited by R.P. Norris, Proceedings of the symposium on Indigenous Astronomy held on 27 November 2009 at Australian Institute for Aboriginal and Torres Strait Islander Studies, Canberra, Australia (in press).

Hamacher, D. W.; O'Neill, C.; Buchel, A.; Britton, T. R.

2010-07-01

296

Groundwater Age in Multi-Level Water Quality Monitor Wells on California Central Valley Dairies  

NASA Astrophysics Data System (ADS)

Dairy farming in California's Central Valley is a significant source of nitrate to underlying aquifers. One approach to mitigation is to implement farm-scale management plans that reduce nutrient loading to groundwater while sustaining crop yield. While the effect of different management practices on crop yield is easily measured, their effect on groundwater quality has only infrequently been evaluated. Documenting and predicting the impact of management on water quality requires a quantitative assessment of transport (including timescale and mixing) through the vadose and saturated zones. In this study, we measured tritium, helium isotopic composition, and noble gas concentrations in groundwater drawn from monitor wells on several dairies in the Lower San Joaquin Valley and Tulare Lake Basin of California's Central Valley in order to predict the timescales on which changes in management may produce observable changes in groundwater quality. These dairies differ in age (from <10 to >100 years old), thickness of the vadose zone (from <10 to 60 m), hydrogeologic setting, and primary source of irrigation water (surface or groundwater). All of the dairies use manure wastewater for irrigation and fertilization. Three of the dairies have implemented management changes designed to reduce nutrient loading and/or water usage. Monitor wells in the southern Tulare Lake Basin dairies were installed by UC-Davis as multi-level nested wells allowing depth profiling of tritium and noble gases at these sites. Tritium/helium-3 groundwater ages, calculated using a simple piston-flow model, range from <2 to >50 years. Initial tritium (the sum of measured tritium and tritiogenic helium-3) is close to or slightly above precipitation in the calculated recharge year for young samples; and significantly above the precipitation curve for older samples. This pattern is consistent with the use of 20-30 year old groundwater recharged before 1980 for irrigation, and illustrates how irrigation with groundwater can complicate the use of tritium alone for age dating. The presence of radiogenic helium-4 in several samples with measurable tritium provides evidence of mixing between pre-modern and younger groundwater. Groundwater age-depth relationships are complicated, consistent with transient flow patterns in shallow agricultural groundwaters affected by irrigation pumping and recharge. For the multi-level installations in the southern dairies, both depth profiles and re-sampling after significant changes in groundwater elevation emphasize the need to sample groundwater within 3 meters of the water table to obtain "first-encounter" groundwater with a tritium/helium-3 age of less than 5 years, and to use age tracers to identify wells and groundwater conditions suitable for monitoring and assessment of best management practice impacts on underlying groundwater quality. This work was carried out with funding from Sustainable Conservation and the California State Water Resources Control Board in collaboration with UC-Davis, and was performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

Esser, B. K.; Visser, A.; Hillegonds, D. J.; Singleton, M. J.; Moran, J. E.; Harter, T.

2011-12-01

297

Dissolved phosphorus distribution in shallow groundwater beneath dairy farms, Central Valley, California  

NASA Astrophysics Data System (ADS)

Concentrated animal farming operations (CAFOs) often produce surface runoff with high phosphorus (P) concentrations, but much less is known about P leaching and distributions in shallow groundwater beneath CAFOs. In this study, concentrations of soluble P were measured in shallow groundwater beneath ten dairies located in the Central Valley, California between 1998 and 2009 to assess spatial and temporal variability in areas of higher and lower hydrogeological vulnerability to groundwater contamination, and to investigate both land uses and physiochemical parameters associated with soluble P distribution. Distribution of bioavailable soil phosphate (bicarbonate extraction) was also examined in soil cores from several of the dairies in order to asses potential links between P distribution in the vadose zone and dissolved P concentrations near the top of the groundwater table. Dissolved P and other geochemical constituents were measured in 200 domestic drinking water wells to examine differences in shallow and deeper groundwater within the region. Samples from dairies and domestic wells were collected from two distinct regions in the Central Valley. The northern region (northeastern San Joaquin Valley) is characterized by a shallower water table, sandy soils, and groundwater discharges to surface water, whereas the southern region (Tulare Lake Basin) is characterized by a much deeper water table and does not have natural discharges of groundwater to surface water. Mean dissolved P concentrations were highest in the two dairies with the shallowest water table and sandiest soils, although dissolved P concentrations were highly variable across monitoring wells within individual dairies. Dissolved P ranged from below detection (< 0.05 mg/L) up to 18.6 mg/L in the northern dairy monitoring wells, and from below detection up to 0.12 mg/L in the southern dairy monitoring wells. For the two dairies with tile drains, discharge from the drains was also sampled, and dissolved P ranged from 1.8-5.3 mg/L. Dissolved P concentrations in dairy monitoring wells did not show distinct patterns associated with different dairy land uses (waste lagoons, corrals, and manured fields); however phosphate concentrations in soil cores appeared to be strongly influenced by dairy land use, with the highest values occurring in cores adjacent to waste lagoons, followed by cores taken from corral areas, and lower values occurring in cores taken from manured fields. All dairy soil cores showed elevated phosphate values in comparison to a control core taken from a field which had not received significant manure inputs. Dissolved P above the detection limit of 0.05 mg/L was measured in 30% of the domestic wells. Dissolved P was significantly correlated to Fe and Mn concentration in the domestic drinking water wells but not in the shallow dairy monitoring wells, suggesting that low oxygen was a major control on dissolved P in the deeper groundwater.

Young, M. B.; Lockhart, K.; Holstege, D.; Applegate, O.; Harter, T.

2012-12-01

298

Movement of Salt and Nitrate in Shallow Groundwater in California's Central Valley - Large Scale Water, Salt, and Nitrate Balance Calculations  

NASA Astrophysics Data System (ADS)

A large-scale analysis of salt and nitrate was performed for the shallow groundwater aquifer of the entire California Central Valley floor (about 20,000 square miles). This analysis combined many different platforms of data in order to complete water and mass balance calculations. Groundwater and surface water quality test data were used in combination with mass loading from a watershed model (the Environmental Protection Agency's Watershed Analysis Risk Management Framework, or WARMF), as well as an integrated hydrologic model that simulates the use and movement of water coupled between the landscape, surface water, and groundwater (the U.S. Geological Survey's Central Valley Hydrologic Model, or CVHM). For this analysis, the Central Valley floor was divided into 22 zones, and the movement of shallow groundwater, surface water, salt, and nitrate was simulated in, out, and between the zones on a quarterly basis for a 20-year simulation period. In this analysis, shallow groundwater is defined by an estimate of the vertical distance water will travel from the water table within 20 years. Fluxes of mass from deep ambient groundwater and ambient surface water quality were estimated from measured concentration data. Quantities of mass were acquired for recharge (from WARMF output) or calculated using concentrations and other water budget components. Flow and volume components were extracted by post-processing CVHM output data. This resulted in a transient water, salt, and nitrate budget for each of the 22 zones. Simulated shallow groundwater concentrations were calculated to investigate water quality trends for the Central Valley. Four zones were identified as areas with the highest concentrations of salt (TDS) in the southwestern portion of the Central Valley; and six zones were identified as areas with the highest nitrate concentrations, mostly in the southeastern portion of the Valley. Additional analyses intended to shift from the large-scale balance calculations to a higher resolution analysis of the movement of water, salt, and nitrate was performed as a 'proof of concept' for two focus areas located in Stanislaus/Merced Counties and the Kings Subbasin, using MODPATH and MODPATH-OBS. Particle tracking was employed for both focus areas to observe the movement of water, salt, and nitrate from recharge zones to monitored wells, or on a cell-by-cell/layer-by-layer basis.

Dalgish, B. A.; Boyle, D.; Kretsinger Grabert, V. J.

2013-12-01

299

Modeling nitrate at domestic and public-supply well depths in the Central Valley, California  

USGS Publications Warehouse

Aquifer vulnerability models were developed to map groundwater nitrate concentration at domestic and public-supply well depths in the Central Valley, California. We compared three modeling methods for ability to predict nitrate concentration >4 mg/L: logistic regression (LR), random forest classification (RFC), and random forest regression (RFR). All three models indicated processes of nitrogen fertilizer input at the land surface, transmission through coarse-textured, well-drained soils, and transport in the aquifer to the well screen. The total percent correct predictions were similar among the three models (6982%), but RFR had greater sensitivity (84% for shallow wells and 51% for deep wells). The results suggest that RFR can better identify areas with high nitrate concentration but that LR and RFC may better describe bulk conditions in the aquifer. A unique aspect of the modeling approach was inclusion of outputs from previous, physically based hydrologic and textural models as predictor variables, which were important to the models. Vertical water fluxes in the aquifer and percent coarse material above the well screen were ranked moderately high-to-high in the RFR models, and the average vertical water flux during the irrigation season was highly significant (p < 0.0001) in logistic regression.

Nolan, Bernard T.; Gronberg, JoAnn M.; Faunt, Claudia C.; Eberts, Sandra M.; Belitz, Ken

2014-01-01

300

Sex-related differences in habitat associations of wintering American Kestrels in California's Central Valley  

USGS Publications Warehouse

We used roadside survey data collected from 19 routes over three consecutive winters from 200708 to 200910 to compare habitat associations of male and female American Kestrels (Falco sparverius) in the Central Valley of California to determine if segregation by sex was evident across this region. As a species, American Kestrels showed positive associations with alfalfa and other forage crops like hay and winter wheat, as well as grassland, irrigated pasture, and rice. Habitat associations of females were similar, with female densities in all these habitats except rice significantly higher than average. Male American Kestrels showed a positive association only with grassland and were present at densities well below those of females in alfalfa, other forage crops, and grassland. Males were present in higher densities than females in most habitats with negative associations for the species, such as orchards, urbanized areas, and oak savannah. The ratio of females to males for each route was positively correlated with the overall density of American Kestrels on that route. Our findings that females seem to occupy higher quality habitats in winter are consistent with observations from elsewhere in North America. ?? 2011 The Raptor Research Foundation, Inc.

Pandolfino, E.R.; Herzog, M.P.; Smith, Z.

2011-01-01

301

Comparison of Summer and Winter California Central Valley Aerosol Distributions from Lidar and MODIS Measurements  

NASA Technical Reports Server (NTRS)

Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2007. While the ground PM(sub 2.5) concentration is highest in the winter, the aerosol optical depth measured from MODIS is highest in the summer. A seasonal comparison shows that PM(sub 2.5) in the winter can exceed summer PM(sub 2.5) by 55%, while summer AOD exceeds winter AOD by 43%. Higher temperatures and wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not surface particulate matter monitors. Temperature inversions, especially during the winter, contribute to higher PM(sub 2.5) measurements at the surface. Measurements of the boundary layer height from lidar instruments provide valuable information need to understand the relationship between satellite measurements of optical depth and in-situ measurements of PM(sub 2.5).

Lewis, Jasper; DeYoung, Russell; Ferrare, Richard; Chu, D. Allen

2010-01-01

302

Data for ground-water test hole near Butte City, Central Valley aquifer project, California  

USGS Publications Warehouse

This report provides preliminary data for the third of seven test holes drilled as part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 32, T. 19 N., R. 1 W., Glenn County, California, about one-half mile south of the town of Butte City. Drilled to a depth of 1,432 feet below land surface, the hole is cased to a depth of 82 feet and equipped with three piezometer tubes to depths of 592 feet, 968 feet, and 1,330 feet. A 5-foot well screen is at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer , and the well bore is filled between the plugs with sediment. Nine cores and 49 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, and chemical quality of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

French, James J.; Page, R.W.; Bertoldi, G.L.

1983-01-01

303

Data for ground-water test hole near Nicolaus, Central Valley aquifer project, California  

USGS Publications Warehouse

Preliminary data are provided for the third of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 2, T.12N., R.3E., Sutter County, California, about 1 1/2 miles northwest of the town of Nicolaus. Drilled to a depth of 1,150 feet below land surface, the hole is cased to a depth of 100 feet and equipped with three piezometer tubes to depths of 311, 711, and 1,071 feet. A 5-foot well screen is set in sand at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer, and the well bore is filled between the plugs with sediment. Thirty-one cores and 34 sidewall cores were recovered. Laboratory tests were made for minerology, consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis of the three tapped zones and measured for water level. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

French, James J.; Page, R.W.; Bertoldi, Gilbert L.

1983-01-01

304

Data for ground-water test hole near Zamora, Central Valley Aquifer Project, California  

USGS Publications Warehouse

Preliminary data are presented for the first of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 SE 1/4 sec. 34, T. 12 N. , R. 1 E., Yolo County, California, about 3 miles northeast of the town of Zamora. Drilled to a depth of 2,500 feet below land surface, the hole is cased to a depth of 190 feet and equipped with three piezometer tubes to depths of 947, 1,401, and 2,125 feet. A 5-foot well screen is at the bottom of each piezometer. Eighteen cores and 68 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, diatom identification, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

French, J.J.; Page, R.W.; Bertoldi, G.L.

1982-01-01

305

Application of pesticide transport model for simulating diazinon runoff in Californias central valley  

NASA Astrophysics Data System (ADS)

Dormant spray application of pesticides to almond and other stone fruit orchards is the main source of diazinon during the winter in California's central valley. Understanding the pesticide transport and the tradeoffs associated with the various management practices is greatly facilitated by the use of physically-based contaminant transport models. In this study, performance of Joyce's et al. (2008) pesticide transport model was evaluated using experimental data collected from two ground treatments such as resident vegetation and bare soil. The model simulation results obtained in calibration and validation process were analyzed for pesticide concentration and total load. The pesticide transport model accurately predicted the pesticide concentrations and total load in the runoff from bare field and was capable of simulating chemical responses to rainfall-runoff events. In case of resident vegetation, the model results exhibited a larger range of variation than was observed in the bare soil simulations due to increased model parameterization with the addition of foliage and thatch compartments. Furthermore, the model was applied to study the effect of runoff lag time, extent of crop cover, organic content of soil and post-application irrigation on the pesticide peak concentration and total load. Based on the model results, recommendations were suggested to growers prior to implementing certain management decisions to mitigate diazinon transport in the orchard's spray runoff.

Joyce, Brian A.; Wallender, Wesley W.; Mailapalli, Damodhara R.

2010-12-01

306

Interpretation of the Last Chance thrust, Death Valley region, California, as an Early Permian de??collement in a previously undeformed shale basin  

USGS Publications Warehouse

The Last Chance thrust, discontinuously exposed over an area of at least 2500 km2 near the south end of the Cordilleran foreland thrust belt in the Death Valley region of east-central California, is controversial because of its poorly constrained age and its uncertain original geometry and extent. We interpret this thrust to be Early Permian in age, to extend throughout a sedimentary basin in which deep-water Mississippian shale overlain by Pennsylvanian and earliest Permian limestone turbidites accumulated, to represent about 30 km of eastward displacement, and to be related to convergence on a northeast-trending segment of the Early Permian continental margin. Last Chance deformation occurred between the times of the Antler and Sonoma orogenies of Late Devonian-Early Mississippian and Late Permian ages, respectively, and followed Early to Middle Pennsylvanian truncation of the continental margin by transform faulting. In the western part of the Mississippian shale basin in east-central California, the originally recognized exposures of the Last Chance thrust show Neoproterozoic and early Paleozoic strata above lower-plate Mississippian shale. Farther east, faults subparallel to bedding above, below, and within the Mississippian shale are interpreted to mark the thrust zone and to represent a regional de??collement. At the eastern margin of the basin, upper-plate thrust slices of deep-water, late Paleozoic strata are interpreted to have piled up against the margin of the Mississippian carbonate shelf to form a large antiformal stack above the Lee Flat thrust, which we regard as the easternmost exposure of the Last Chance thrust. Thrust loading depressed the western part of the shelf, creating a new sedimentary basin in which about 3.5 km of younger Early Permian deep-water strata were deposited against the antiformal stack. Later, probably in the Late Permian, other thrusts, including the Inyo Crest thrust, which was subsequently overlapped by Early to Middle(?) Triassic marine strata, cut across the Last Chance thrust. We interpret the Last Chance thrust as similar in many ways to Appalachian-type de??collements in which the zone of thrusting is localized along a shale interval. The Last Chance thrust, however, has been dismembered during later geologic events so that its original geometry has been obscured. Our model may have unrecognized analogs in other structurally complex shale basins in which the initial deformation was along a major shale unit. ?? 2005 Elsevier B.V. All rights reserved.

Stevens, C.H.; Stone, P.

2005-01-01

307

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

NASA Astrophysics Data System (ADS)

The Middle Aterno River Valley is characterised by different Quaternary tectonic depressions localised along the present course of the Aterno River (Central Apennine) .This valley includes the L'Aquila and Paganica-Castelnuovo-San Demetrio tectonic basins, to the North, the Middle Aterno Valley and the Subequana tectonic basin, to the South. The aim of this contribution is to improve the knowledge about the Quaternary geomorphological and tectonic evolution of this portion of the Apennine chain. A synchronous lacustrine depositional phase is recognized in all these basins and attributed to the Early Pleistocene by Falcucci et al. (2012). At that time, this sector of the chain showed four distinct closed basins, hydrologically separated from each other and from the Sulmona depression. This depression, actually a tectonic basin too, was localized South of the Middle Aterno River Valley and it was drained by an endorheic hydrographic network. The formation of these basins was due to the activity of different fault systems, namely the Upper Aterno River Valley-Paganica system and San Pio delle Camere fault, to the North, and the Middle Aterno River Valley-Subequana Valley fault system to the South. These tectonic structures were responsible for the origin of local depocentres inside the depressions which hosted the lacustrine basins. Ongoing surveys in the uppermost sectors of the Middle Aterno River Valley revealed the presence of sub-horizontal erosional surfaces that are carved onto the carbonate bedrock and suspended several hundreds of metres over the present thalweg. Gently dipping slope breccias referred to the Early Pleistocene rest on these surfaces, thus suggesting the presence of an ancient low-gradient landscape adjusting to the local base level.. Subsequently, this ancient low relief landscape underwent a strong erosional phase during the Middle Pleistocene. This erosional phase is testified by the occurrence of valley entrenchment and of coeval fluvial deposition within the Middle Aterno River Valley. These fluvial deposits are deeply embedded into the lacustrine sequence, thus suggesting the happening of a hydrographic connection among the originally separated tectonic depressions. This was probably due to the headward erosion by streams draining the Sulmona depression that progressively captured the hydrological networks of the Subequana basin, the Middle Aterno Valley, the L'Aquila and Paganica-Castelnuovo-San Demetrio basins to the North. Stream piracy was probably helped by an increase of the regional uplift rate, occurred between the Lower and the Middle Pleistocene. To reconstruct the paleo-landscape that characterised the early stages of these basins formation we sampled the remnants of the Quaternary erosinal/depositional surfaces and reconstructed the ancient topographic surfaces using the Topo to Raster tool of ArcGIS 10.0 package. Finally we have cross-checked the geological and geomorphological data with the model of the Middle Aterno River paleo-drainage basin obtained through the GIS based method. References Falcucci E., Scardia G., Nomade S., Gori S., Giaccio B., Guillou H., Fredi P. (2012). Geomorphological and Quaternary tectonic evolution of the Subequana basin and the Middle Aterno Valley (central Apennines).16th Joint Geomorphological Meeting Morphoevolution of Tectonically Active Belts Rome, July 1-5, 2012

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

2014-05-01

308

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

USGS Publications Warehouse

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.

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

2002-01-01

309

Estimation of Evapotranspiration of Almond orchards using Remote Sensing based SEBAL model in Central Valley, California  

NASA Astrophysics Data System (ADS)

Evapotranspiration is one of the main components of the hydrologic cycle and its impact to hydrology, agriculture,forestry and environmental studies is very crucial. SEBAL (Surface Energy Balance Algorithm for Land) is an image-processing model comprised of twenty-five computational sub-models that computes actual evapotranspiration (ETa) and other energy exchanges as a component of energy balance which is used to derive the surface radiation balance equation for the net surface radiation flux (Rn) on a pixel-by-pixel basis. For this study, SEBAL method is applied to Level 1B dataset of visible, near-infrared and thermal infrared radiation channels of MASTER instrument on-board NASA-DC 8 flight. This paper uses the SEBAL method to (1) investigate the spatial distribution property of land surface temperature (Ls), NDVI, and ETa over the San Joaquin valley. (2) Estimate actual evapotranspiration of almond class on pixel-by-pixel basis in the Central valley, California. (3) Comparison of actual Evapotranspiration obtained from SEBAL model with reference evapotranspiration (Eto) using Penman Monteiths method based on the procedures and available data from California Irrigation Management Information System (CIMIS) stations. The results of the regression between extracted land surface temperature, NDVI and, evapotranspiration show negative (-) correlation. On the other hand Ls possessed a slightly stronger negative correlation with the ETa than with NDVI for Almond class. The correlation coefficient of actual ETa estimates from remote sensing with Reference ETo from Penmann Monteith are 0.8571. ETa estimated for almond crop from SEBAL were found to be almost same with the CIMIS_Penman Monteith method with bias of 0.77 mm and mean percentage difference is 0.10%. These results indicate that combination of MASTER data with surface meteorological data could provide an efficient tool for the estimation of regional actual ET used for water resources and irrigation scheduling and management. Keywords: Evapotranspiration, Hydrologic cycle, SEBAL, net surface radiation flux, MASTER, NDVI, Penman Monteith, CIMIS, Surface Temperature

Roy, S.; Ustin, S.; Kefauver, S. C.

2009-12-01

310

Middle Pleistocene palaeoenvironments and the late Lower-Middle Palaeolithic of the Hrazdan valley, central Armenia  

NASA Astrophysics Data System (ADS)

The palaeogeographic importance of the southern Caucasus in the Pleistocene as a region of population expansion and contraction between Africa, the Levant and Eurasia is well established as a result of recent archaeological works in the Republics of Armenia and Georgia. Not only does the area have a unique Palaeolithic record, but the presence of volcanic layers in association with archaeological sites and off site sequences means that there is the potential for both high precision dating and correlation. The Hrazdan valley, central Armenia is a case in point. Late Lower to late Middle Palaeolithic sites found as a result of systematic survey and then explored in excavations in 2008-2011 are associated with various volcanogenic strata. 40K/40Ar and 40Ar/39Ar dating in the 1970-2000s demonstrates the onset of volcanism in the adjacent Gegham range in the period 700-500ky BP, while recent 40Ar/39Ar dates on the latest lava from the Gutanasar volcano shows the latest effusive eruption to have occurred at c. 200 ky BP. Nine Middle Pleistocene lavas from the intervening period have been mapped in the Hrazdan valley in a 15km-long study area 12km north-east of Yerevan. Several of the basalts seal terrestrial strata, and thereby bury and 'fossilize' earlier landscapes. The most significant of these is sandwiched between basalts dating to 200 and 440ky BP, where a 135m-long exposure contains a palaeosol developing in floodplain alluvium and in situ archaeological material (Nor Geghi 1). Morphological and micromorphological examination of site strata suggest that hominin activity took place during a temperate episode, which 40Ar/39Ar dating of interbedded crypotephra suggests was MIS 9e. However, strata at other locales buried beneath the same 200ky BP basalt suggest that the landscape occupied by these hominids was a mosaic of river channels, floodplains and lakes. The fossilized MIS 9 landscape is not unique as further lacustrine deposits are buried beneath earlier Middle Pleistocene basalts, although earlier archaeological sites have yet to be found.

Wilkinson, Keith; Adler, Daniel; Nahapetyan, Samvel; Smith, Victoria; Mark, Darren; Mallol, Carolina; Blockley, Simon; Gasparian, Boris

2014-05-01

311

Stratigraphy and palaeogeography of the Godavari Supergroup in the south-central Pranhita-Godavari Valley, south India  

NASA Astrophysics Data System (ADS)

The Proterozoic succession of the Pranhita-Godavari Valley (PG Valley), defined as the Godavari Supergroup, occurs in two NW-SE trending belts flanking the margins of the Valley. The Supergroup comprises several unconformity-bound sequences of group status, and exhibits strong regional variations in the distribution of different groups deposited in widely variable conditions, ranging from fan-alluvial setting to deep-water slope, base-of-slope and basinal environments. The lithologic assemblages indicate that the basin experienced multiple rifting, and tectonic environment varied from an unstable rift setting to a stable shelf regime. The Godavari Supergroup, with a complex history of stratigraphic evolution, is still plagued by multiple problems of classification and correlation that have long been the major impediments to basin analysis. In the present paper, the attributes of the genetically linked stratal packages, the unconformities separating them, and their correlation in the south-central part of the Valley have been critically evaluated to address the problems of regional stratigraphy. The Godavari Supergroup is bounded by two inter-regional unconformities, separating it from the underlying crystalline cratonic basement, and from the overlying Gondwana sedimentary rocks of late Paleozoic-Mesozoic age. The Supergroup, in turn, is subdivided into four major sequences by three regional unconformities in the south-central part of the Valley. Comparison of stratigraphic profiles at different points indicates that the thickness of the unconformity-bound sequences, or of individual formations, and also the number of formations, increases from the central part of the Valley towards the southeast. The stratigraphic relationships collectively suggest that the basin deepened and opened in a southeasterly direction. The basin in its southeastern part appears to have been much wider than the present day outcrop width, and to have been continuous with other adjoining Proterozoic basins. The central part of the basin was a relatively stable and positive area compared to the southern part, where the basin floor repeatedly moved across the base level to the order of several hundred meters. The amplitude of movements indicates tectonically controlled subsidence and uplift.

Chaudhuri, Asru K.

2003-03-01

312

Depositional microfacies and burial diagenesis of Upper Jurassic Cotton Valley Limestone, Teague Townsite field, central Texas  

Microsoft Academic Search

The Cotton Valley Limestone, like the older Smackover, was deposited on a ramp where the monotonous regional topography was punctuated by salt-generated and basement highs that greatly influenced local depositional environments. Teague Townsite field is located above a salt ridge that was once divided into several domes where Cotton Valley grainstones were deposited. Open marine wackestones and packstones surrounded those

W. M. Ahr; R. C. Faucette; C. Steffensen

1983-01-01

313

A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California  

SciTech Connect

In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this ''second-generation'' regional model was to enhance the knowledge and understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-stat e representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration.

D'Agnese, F.A.; O'Brien, G.M.; Faunt, C.C.; Belcher, W.R.; San Juan, Carma

2002-11-22

314

Tilt and rotation of the footwall of a major normal fault system: Paleomagnetism of the Black Mountains, Death Valley extended terrane, California  

SciTech Connect

Paleomagnetic data have been obtained from Miocene intrusions, Proterozoic Paleomagnetic data have been obtained from Miocene intrusions, Proterozoic crystalline rocks and cross-cutting mafic to felsic dikes to evaluate footwall deformation during extension and unroofing of the crystalline core of the Black Mountains, Death Valley, California. Synrift intrusions contain a well-defined and, at the site level, well-grouped magnetization, interpreted to be of dual polarity, whose in situ direction is discordant in declination and inclination with an expected late Cenozoic reference direction. In situ site mean directions of this magnetization are directed towards the west and west-northwest with moderate to shallow positive and negative inclinations. The variation in magnetization direction, particularly inclination, with site locality around the turtleback structures along the western flank of the Black Mountains suggests folding of the intrusion after remanence acquisition. Two populations of in situ site means are identified: one with southwest declination and negative inclination, the other with northward declination and positive inclination. A preferred interpretation for footwall deformation involves, from oldest to youngest: (1) northeast-side up tilting of 20--40[degree] and local folding of the crystalline rocks associated with early structures (the Death Valley turtlebacks) between 11.6 and 8.7 Ma, (2) progressive east to west footwall unroofing between 8.7 and [approximately]6.5 Ma, and (3) large-scale clockwise rotation (50--80[degree]) after the core detached from stable terrane to the west. The authors interpret late rotation as oroflexure related to right-lateral shear along the Death Valley fault zone.

Holm, D.K. (Kent State Univ., OH (United States). Dept. of Geology); Geissman, J.W. (Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Geology and Planetary Sciences); Wernicke, B. (California Inst. of Tech., Pasadena, CA (United States). Dept. of Geology and Planetary Sciences)

1993-04-01

315

Principal facts for gravity stations in the Dry Valley area, west-central Nevada and east-central California  

USGS Publications Warehouse

In June, 2002, the U.S. Geological Survey (USGS) established 143 new gravity stations and 12 new rock samples in the Dry Valley area, 30 miles north of Reno, Nevada, on the California - Nevada border (see fig. 1). This study reports on gravity, magnetic, and physical property data intended for use in modeling the geometry and depth of Dry Valley for groundwater analysis. It is part of a larger study that aims to characterize the hydrologic framework of several basins in Washoe County. Dry Valley is located south of the Fort Sage Mountains and south-east of Long Valley, on USGS 7.5 quadrangles Constantia and Seven Lakes (fig. 2). The Cretaceous granitic rocks and Tertiary volcanic rocks that bound the sediment filled basin (fig. 3) may be especially important to future modeling because of their impact on groundwater flow. The granitic and volcanic rocks of Dry Valley exhibit densities and magnetic susceptibilities higher than the overlaying sediments, and create a distinguishable pattern of gravity and magnetic anomalies that reflect these properties.

Sanger, Elizabeth A.; Ponce, David A.

2003-01-01

316

Evolution of Late Miocene to Contemporary Displacement Transfer Between the Northern Furnace Creek and Southern Fish Lake Valley Fault Zones and the Central Walker Lane, Western Great Basin, Nevada  

NASA Astrophysics Data System (ADS)

Late Miocene to contemporary displacement transfer from the north Furnace Creek (FCF) and southern Fish Lake Valley (FLVF) faults to structures in the central Walker Lane was and continues to be accommodated by a belt of WNW-striking left-oblique fault zones in the northern part of the southern Walker Lane. The WNW fault zones are 2-9 km wide belts of anastomosing fault strands that intersect the NNW-striking FCF and southern FLVF in northern Death Valley and southern Fish Lake Valley, respectively. The WNW fault zones extend east for over 60 km where they merge with a 5-10 km wide belt of N10W striking faults that marks the eastern boundary of the southern Walker Lane. Left-oblique displacement on WNW faults progressively decreases to the east, as motion is successively transferred northeast on NNE-striking faults. NNE faults localize and internally deform extensional basins that each record cumulative net vertical displacements of between 3.0 and 5.2 km. The transcurrent faults and associated basins decrease in age from south to north. In the south, the WNW Sylvania Mountain fault system initiated left-oblique motion after 7 Ma but does not have evidence of contemporary displacement. Farther north, the left-oblique motion on the Palmetto Mountain fault system initiated after 6.0 to 4.0 Ma and has well-developed scarps in Quaternary deposits. Cumulative left-lateral displacement for the Sylvania Mountain fault system is 10-15 km, and is 8-12 km for the Palmetto fault system. The NNE-striking faults that emanate from the left-oblique faults merge with NNW transcurrent faults farther north in the eastern part of the Mina deflection, which links the Owens Valley fault of eastern California to the central Walker Lane. Left-oblique displacement on the Sylvania Mountain and Palmetto Mountain fault zones deformed the Furnace Creek and Fish Lake Valley faults. Left-oblique motion on Sylvania Mountain fault deflected the FCF into the 15 km wide Cucomungo Canyon restraining bend, segmented the >3.0 km deep basin underlying southern Fish Lake Valley, and formed a 2 km wide restraining bend in the FLVF. Part of the left-oblique motion on the Palmetto Mountain fault zone crosses Fish Lake Valley and offsets the FLVF in a 3 km wide restraining bend with the remainder being taken-up by NNW structures along the eastern side of southern Fish Lake Valley.

Oldow, J. S.; Geissman, J. W.

2013-12-01

317

Annual ground-water discharge by evapotranspiration from areas of spring-fed riparian vegetation along the eastern margin of Death Valley, 2000-02  

USGS Publications Warehouse

Flow from major springs and seeps along the eastern margin of Death Valley serves as the primary local water supply and sustains much of the unique habitat in Death Valley National Park. Together, these major spring complexes constitute the terminus of the Death Valley Regional Ground-Water Flow System--one of the larger flow systems in the Southwestern United States. The Grapevine Springs complex is the least exploited for water supply and consequently contains the largest area of undisturbed riparian habitat in the park. Because few estimates exist that quantify ground-water discharge from these spring complexes, a study was initiated to better estimate the amount of ground water being discharged annually from these sensitive, spring-fed riparian areas. Results of this study can be used to establish a basis for estimating water rights and as a baseline from which to assess any future changes in ground-water discharge in the park. Evapotranspiration (ET) is estimated volumetrically as the product of ET-unit (general vegetation type) acreage and a representative ET rate. ET-unit acreage is determined from high-resolution multi-spectral imagery; and a representative ET rate is computed from data collected in the Grapevine Springs area using the Bowen-ratio solution to the energy budget, or from rates given in other ET studies in the Death Valley area. The ground-water component of ET is computed by removing the local precipitation component from the ET rate. Two different procedures, a modified soil-adjusted vegetation index using the percent reflectance of the red and near-infrared wavelengths and land-cover classification using multi-spectral imagery were used to delineate the ET units within each major spring-discharge area. On the basis of the more accurate procedure that uses the vegetation index, ET-unit acreage for the Grapevine Springs discharge area totaled about 192 acres--of which 80 acres were moderate-density vegetation and 112 acres were high-density vegetation. ET-unit acreage for two other discharge areas delineated in the Grapevine Springs area (Surprise Springs and Staininger Spring) totaled about 6 and 43 acres, respectively; and for the discharge areas delineated in the Furnace Creek area (Nevares Springs, Cow Creek-Salt Springs, Texas Spring, and Travertine Springs) totaled about 29, 13, 11, and 21 acres, respectively. In discharge areas other than Grapevine Springs, watering and spring diversions have altered the natural distribution of the vegetation. More...

Laczniak, Randell J.; Smith, J. LaRue; DeMeo, Guy A.

2006-01-01

318

The role of cornice fall avalanche sedimentation in the valley Longyeardalen, Central Svalbard  

NASA Astrophysics Data System (ADS)

In arctic and alpine high relief landscapes snow avalanches are traditionally ranked behind rockfall in terms of their significance for mass wasting processes of rock slopes. Cornice fall avalanches are at present the most dominant snow avalanche type at two slope systems, called Nybyen and Larsbreen, in the valley Longyeardalen in Central Svalbard. Both slope systems are situated on NW-facing lee slopes underneath large summit plateau, where cornices form annually, and high frequency and magnitude cornice fall avalanching is observed by daily automatic time-lapse photography. In addition, rock debris sedimentation by these cornice fall avalanches was measured directly in either permanent sediment traps or by snow inventories. The results from a maximum of 7 yr of measurements in a total of 13 catchments show maximum avalanche sedimentation rates ranging from 8.2 to 38.7 kg m-2 at Nybyen and from 0.8 to 55.4 kg m-2 at Larsbreen. Correspondingly, the avalanche fan-surfaces accreted annually in a~maximum range from 3.7 to 13 mm yr-1 at Nybyen and from 0.3 to 21.4 mm yr-1 at Larsbreen. This comparably efficient rock slope mass wasting is due to collapsing cornices producing cornice fall avalanche with high rock debris content throughout the entire winter. The rock debris of different origin stems from the plateau crests, the adjacent free rock face and the transport pathway, accumulating distinct avalanche fans at both slope systems and contributing to the development of a rock glacier at the Larsbreen slope system.

Eckerstorfer, M.; Christiansen, H. H.; Rubensdotter, L.; Vogel, S.

2012-12-01

319

Dating Pliocene lacustrine sediments in the central Jordan Valley, Israel Implications for cosmogenic burial dating  

NASA Astrophysics Data System (ADS)

Cosmogenic burial dating of sediments is usually used at sites with relatively simple or known exposure-burial histories, such as in caves. In an attempt to extend the applicability of the method to other common geological settings (i.e. the dating of late Neogene sedimentary formations), where much less is known about the exposure-burial history, we apply the cosmogenic burial method on Pliocene-early Pleistocene (1.5-4.5 Ma) lacustrine sediments in the central Jordan Valley, Israel. 26Al, 10Be, and 21Ne concentrations in quartz were obtained from a 170 m tectonically-tilted section. Assuming fast burial and no post-burial production we obtained burial ages which range between 3.5 and 5.3 Ma. Integrating simple geological reasoning and the cosmogenic nuclide data, post burial production is found to be insignificant. We also found that the samples contain two distinct populations of grains (chert and quartz) from two different sources which experienced different pre-burial exposure histories. The cosmogenic nuclide concentrations in the samples are in accordance with those expected for the mixing of two sources, and the burial ages computed for both end members agree. Theoretical calculations of two-source mixing show that initial 26Al/10Be ratios are depressed relative to the expected surface ratios and may result in burial ages overestimated by as much as 500 ka. Using ages derived from cosmogenic nuclides, independent age constraints, and magnetostratigraphy we correlate the bottom of the section to the Cochiti Normal magnetic subchron (4.19-4.30 Ma) within the Reverse Gilbert chron, and the top of the section to the Reverse subchron at the top of the Gilbert chron (3.60-4.19 Ma).

Davis, M.; Matmon, A.; Fink, D.; Ron, H.; Niedermann, S.

2011-05-01

320

Identifying Key Vulnerabilities in Current Management of California Central Valley for the California Water Plan  

NASA Astrophysics Data System (ADS)

The California Department of Water Resources (DWR), for its 2013 Update of the California Water Plan (CWP), is building new analytic capabilities for developing and evaluating regional and state-wide water management strategies. These strategies are intended to address growing and diverse water needs coupled with uncertain future hydrologic conditions and available supplies. Recognizing the significant uncertainty about future water management conditions, DWR is utilizing new robust decision methods to identify robust and adaptive water management strategies. This talk will describe a recently completed application of Robust Decision Making (RDM) for long-term water planning as part of the 2013 CWP Update. This analysis utilizes a new hydrologic / water management model of the Sacramento River, San Joaquin River, and Tulare hydrologic regions, running the model under hundreds of potential futures. These futures consider potential variation in demographic growth, land-use patterns, drought length and timing, and other climate factors from projections generated by downscaled global circulation models. Cluster-finding "scenario discovery" algorithms, applied to the resulting database of simulation model results, identify the key characteristics of future conditions where current management fails to meet a wide range of policy objectives. These "vulnerabilities" provide the foundation for developing more robust and adaptive response packages and the considering tradeoffs between such response packages. This analysis will provide guidance for considering response packages to meet the challenges posed by future conditions in the California Central Valley and provides a widely applicable new approach for making water management plans more cognizant and responsive to a wide range of uncertainties.

Bloom, E.; Groves, D.; Joyce, B. A.; Juricich, R.

2012-12-01

321

Downscaling GRACE satellite data for sub-region groundwater storage estimates in California's Central Valley  

NASA Astrophysics Data System (ADS)

The Central Valley aquifer (CVA) is a vital economic and environmental resource for California and the United States, and supplies water for one of the most agriculturally productive regions in the world. Recent estimates of groundwater (GW) availability in California have indicated declines in GW levels that may pose a threat to sustainable groundwater use in this region. The Gravity Recovery and Climate Experiment (GRACE) can be used to estimate variations in total water storage (TWS) and are therefore used to estimate GW storage changes within the CVA. However, using GRACE data in the CVA is challenging due to the coarse spatial resolution and increased error. To compensate for this, we used a statistical downscaling approach applied to GRACE data at the sub-region level using GW storage estimates from the California Department of Water Resources' (DWR) C2VSim hydrological model. This method produced a spatially and temporally variable GW anomaly dataset for sub-region GW management and for analysis of GW changes influenced by spatial and temporal variability. An additional challenge for this region is the influence of natural climate variability, altering GW recharge and influencing pumping practices. Understanding the effects of climate variability on GW storage changes, may improve GRACE TWS and GW estimates during periods of increased rain or droughts. Thus, the GRACE TWS and GW storage estimates were compared to the El Nio Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) using singular spectral analysis (SSA). Results from SSA indicate that variations in GRACE TWS are moderately correlated to PDO (10-25 year cycle), although low correlations were observed when compared to ENSO (2-7 year cycle). The incorporation of these new methods for estimating variations in groundwater storage in highly productive aquifers may improve water management techniques in California.

Kuss, A. M.; Newcomer, M. E.; Hsu, W.; Bourai, A.; Puranam, A.; Landerer, F. W.; Schmidt, C.

2012-12-01

322

Fluxes of BVOC and tropospheric ozone from a Citrus orchard in the California Central Valley  

NASA Astrophysics Data System (ADS)

Citrus plants, especially oranges, are widely cultivated in many countries experiencing Mediterranean climates. In many of these areas, orchards are often exposed to high levels of tropospheric ozone (O3) due to their location in polluted airsheds. Citrus take up O3 through their stomata and emit biogenic volatile organic compounds (BVOC), which can contribute to non-stomatal O3 removal through fast gas-phase reactions with O3. The study was performed in a valencia orange orchard in Exeter, California. From fall 2009 to winter 2010, CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously in situ with specific sensors (e.g. fast ozone analyzer and Proton Transfer Reaction Mass Spectrometer) using the eddy covariance techniques. Vertical concentration gradients of these compounds were also measured at 4 heights from the orchard floor to above the canopy. We observed high levels (up to 60 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 7 nmol m-2 s-1) followed by acetone. Monoterpenes fluxes were also recorded during the all vegetative period, with the highest emissions taking place during flowering periods, and in general highly temperature dependent. The orchard represented a sink for ozone, with uptake rates on the order of 10 nmol m-2 s-1 during the central hours of the day. We found that BVOC played a major role in removing ozone through chemical reactions in the gas-phase, while only up to 40 % of ozone was removed via stomatal uptake. The current research aimed at investigating the fate of BVOC emitted from orange trees will help understanding the role of Citrus orchards in the complex oxidation mechanisms taking place in the polluted atmosphere of the San Joaquin Valley (California).

Fares, S.; Park, J.; Weber, R.; Gentner, D. R.; Karlik, J. F.; Goldstein, A. H.

2011-12-01

323

Soil chemical changes under irrigated mango production in the Central So Francisco River Valley, Brazil.  

PubMed

Irrigated areas in Brazil's Central So Francisco River Valley have experienced declines in productivity, which may be a reflection of changes in soil chemical properties due to management. This study was conducted to compare the chemical composition of soil solutions and cation exchange complexes in a five-year-old grove of irrigated mango (Mangifera indica L. cv. Tommy Atkins) with that of an adjacent clearing in the native caatinga vegetation. A detailed physiographic characterization of the area revealed a subsurface rock layer, which was more undulating than the current land surface, and identified the presence of a very saline and sodic (1045 microS cm(-1), sodium adsorption ratio [SAR] = 5.19) ground water table. While changes in concentrations of Ca, Mg, and K could be attributed to direct management inputs (fertilization and liming with dolomite), increases in Na suggested average annual capillary rise from the ground water table of 28 L m(-2). Accordingly, soil salinity levels appeared to be more dependent on surface elevation than the elevation of the rock layer or sediment thickness. The apparent influence of land surface curvature on water redistribution and the solution chemistry was more pronounced under irrigated mango production. In general, salinity levels had doubled in the mango grove and nearly tripled under the canopies, after only five years of irrigation. Though critical saline or sodic conditions were not encountered, the changes observed indicate a need for more adequate monitoring and management of water and salt inputs despite the excellent water quality of the So Francisco River. PMID:12931897

Heck, R J; Tiessen, H; Salcedo, I H; Santos, M C

2003-01-01

324

Land-use and land-cover dynamics in the central rift valley of Ethiopia.  

PubMed

Understanding the complexity of land-use and land-cover (LULC) changes and their driving forces and impacts on human and environmental security is important for the planning of natural resource management and associated decision making. This study combines and compares participatory field point sampling (pfps) and remote sensing to explore local LULC dynamics. The study was conducted in two peasant associations located in the central Ethiopian Rift Valley, which is a dry-land mixed farming area exposed to rapid deforestation. From 1973-2006, the area of cropland doubled at the expense of woodland and wooded-grassland in both of the study sites. Major deforestation and forest degradation took place from 1973-1986; woodland cover declined from 40% to 9% in one of the study sites, while the other lost all of its original 54% woodland cover. Our study concludes that assessing LULC dynamics using a combination of remote sensing and pfps is a valuable approach. The two methods revealed similar LULC trends, while the pfps provided additional details on how farmers view the changes. This study documents dramatic trends in LULC over time, associated with rapid population growth, recurrent drought, rainfall variability and declining crop productivity. The alarming nature of these trends is reflected in a decrease in the livelihood security of local communities and in environmental degradation. Given these dry-land conditions, there are few opportunities to improve livelihoods and environmental security without external support. If negative changes are to be halted, action must be taken, including building asset bases, instituting family planning services, and creating opportunities outside these marginal environments. PMID:19688359

Garedew, Efrem; Sandewall, Mats; Sderberg, Ulf; Campbell, Bruce M

2009-10-01

325

Strike-Slip displacement along the Furnace Creek Fault Zone, southern Basins and Ranges, Death Valley, California  

Microsoft Academic Search

The southern Basins and Ranges contain several strike-slip fault zones in addition to predominant normal faults. One of the strike-slip faults is the Furnace Creek fault zone (FCFZ) which extends from the Amorgosa Valley in eastern California northwestward continuously about 200 km and terminates in the Fish Lake Valley in Nevada. The fault zone is a part of the Eastern

W. Baucke; I. Cemen

2007-01-01

326

Studies of geology and hydrology in the Basin and Range province, southwestern United States, for isolation of high-level radioactive waste-characterization of the Death Valley region, Nevada and California  

SciTech Connect

The Death Valley region, Nevada and California, in the Basin and Range province, is an area of about 80,200 sq km located in southern Nevada and southeastern California. Precambrian metamorphic and intrusive basement rocks are overlain by a thick section of Paleozoic clastic and evaporitic sedimentary rocks. Mesozoic and Cenozoic rocks include extrusive and intrusive rocks and clastic sedimentary rocks. Structural features within the Death Valley indicate a long and complex tectonic evolution from late Precambrian to the present. Potential repository host media in the region include granite and other coarse-grained plutonic rocks, ashflow tuff, basaltic and andesitic lava flows, and basin fill. The Death Valley region is composed largely of closed topographic basins that are apparently coincident with closed groundwater flow systems. In these systems, recharge occurs sparingly at higher altitudes by infiltration of precipitation or by infiltration of ephemeral runoff. Discharge occurs largely by spring flow and by evaporation and transpiration in the playas. Death Valley proper, for which the region was named, is the ultimate discharge area for a large, complex system of groundwater aquifers that occupy the northeastern part of the region. The deepest part of the system consists of carbonate aquifers that connect closed topographic basins at depth. The discharge from the system occurs in several intermediate areas that are geomorphically, stratigraphically, and structurally controlled. Ultimately, most groundwater flow terminates by discharge to Death Valley; groundwater is discharged to the Colorado River from a small part of the region.

Bedinger, M.S.; Sargent, K.A.; Langer, W.H. (eds.)

1989-01-01

327

Cell Death, Neuronal Plasticity and Functional Loading in the Development of the Central Nervous System  

NASA Technical Reports Server (NTRS)

Research on the precise timing and regulation of neuron production and maturation in the vestibular and visual systems of Wistar rats and several inbred strains of mice (C57B16 and Pallid mutant) concentrated upon establishing a timing baseline for mitotic development of the neurons of the vestibular nuclei and the peripheral vestibular sensory structures (maculae, cristae). This involved studies of the timing and site of neuronal cell birth and preliminary studies of neuronal cell death in both central and peripheral elements of the mammalian vestibular system. Studies on neuronal generation and maturation in the retina were recently added to provide a mechanism for more properly defining the in utero' developmental age of the individual fetal subject and to closely monitor potential transplacental effects of environmentally stressed maternal systems. Information is given on current efforts concentrating upon the (1) perinatal period of development (E18 thru P14) and (2) the role of cell death in response to variation in the functional loading of the vestibular and proprioreceptive systems in developing mammalian organisms.

Keefe, J. R.

1985-01-01

328

The changing pattern of perinatal mortality and causes of death in central Anatolian region of Turkey.  

PubMed

In this study, the perinatal mortality is presented in 2009 compared to 1998. Changing patterns of the perinatal mortality rate (PNMR), the stillbirth rate (SBR), early neonatal mortality rate (ENMR) and the causes of the perinatal mortality in Zekai Tahir Burak Women's Health Education and Research Hospital (ZTBH) were described. This is the largest maternity hospital of Ankara in the central Anatolian region of Turkey. The total deliveries were 22,777 and 18,567 in 1998 and 2009, respectively. PNMR was 27.7 per 1000, and SBR was 23.7 per 1000 total births. ENMR was 4 per 1000 in 1998. PNMR is 20.7 per 1000, and SBR was 16.3 per 1000 and ENMR was 4.6 per 1000 total births in 2009. It is important to know the causes of mortality. In this study, the causes of perinatal deaths were classified according to the Wigglesworth classification. Antepartum stillbirth (62.3%) was the most frequent cause in 1998. Perinatal asphyxia is the majority (46.6%) of the perinatal deaths in 2009. This study shows that even prenatal care is getting better, obstetric care as well as close follow-up throughout the intrapartum period and diminishing the preterm delivery rate is also important for preventing and reducing perinatal mortality. PMID:22339476

Ecevit, Ayse; Oguz, Suna Serife; Tarcan, Aylin; Yazici, Canan; Dilmen, Ugur

2012-09-01

329

Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California  

USGS Publications Warehouse

This geologic map and pamphlet focus on the stratigraphy, depositional history, and paleogeographic significance of upper Paleozoic rocks exposed in the Marble Canyon area in Death Valley National Park, California. Bedrock exposed in this area is composed of Mississippian to lower Permian (Cisuralian) marine sedimentary rocks and the Jurassic Hunter Mountain Quartz Monzonite. These units are overlain by Tertiary and Quaternary nonmarine sedimentary deposits that include a previously unrecognized tuff to which we tentatively assign an age of late middle Miocene (~12 Ma) based on tephrochronologic analysis, in addition to the previously recognized Pliocene tuff of Mesquite Spring. Mississippian and Pennsylvanian rocks in the Marble Canyon area represent deposition on the western continental shelf of North America. Mississippian limestone units in the area (Tin Mountain, Stone Canyon, and Santa Rosa Hills Limestones) accumulated on the outer part of a broad carbonate platform that extended southwest across Nevada into east-central California. Carbonate sedimentation was interrupted by a major eustatic sea-level fall that has been interpreted to record the onset of late Paleozoic glaciation in southern Gondwana. Following a brief period of Late Mississippian clastic sedimentation (Indian Springs Formation), a rise in eustatic sea level led to establishment of a new carbonate platform that covered most of the area previously occupied by the Mississippian platform. The Pennsylvanian Bird Spring Formation at Marble Canyon makes up the outer platform component of ten third-order (1 to 5 m.y. duration) stratigraphic sequences recently defined for the regional platform succession. The regional paleogeography was fundamentally changed by major tectonic activity along the continental margin beginning in middle early Permian time. As a result, the Pennsylvanian carbonate shelf at Marble Canyon subsided and was disconformably overlain by lower Permian units (Osborne Canyon and Darwin Canyon Formations) representing part of a deep-water turbidite basin filled primarily by fine-grained siliciclastic sediment derived from cratonal sources to the east. Deformation and sedimentation along the western part of this basin continued into late Permian time. The culminating phase was part of a regionally extensive late Permian thrust system that included the Marble Canyon thrust fault just west of the present map area.

Stone, Paul; Stevens, Calvin H.; Belasky, Paul; Montaez, Isabel P.; Martin, Lauren G.; Wardlaw, Bruce R.; Sandberg, Charles A.; Wan, Elmira; Olson, Holly A.; Priest, Susan S.

2014-01-01

330

Data network, collection, and analysis in the Diamond Valley flow system, central Nevada  

USGS Publications Warehouse

Future groundwater development and its effect on future municipal, irrigation, and alternative energy uses in the Diamond Valley flow system are of concern for officials in Eureka County, Nevada. To provide a better understanding of the groundwater resources, the U.S. Geological Survey, in cooperation with Eureka County, commenced a multi-phase study of the Diamond Valley flow system in 2005. Groundwater development primarily in southern Diamond Valley has resulted in water-level declines since the 1960s ranging from less than 5 to 100 feet. Groundwater resources in the Diamond Valley flow system outside of southern Diamond Valley have been relatively undeveloped. Data collected during phase 2 of the study (2006-09) included micrometeorological data at 4 evapotranspiration stations, 3 located in natural vegetation and 1 located in an agricultural field; groundwater levels in 95 wells; water-quality constituents in aquifers and springs at 21 locations; lithologic information from 7 recently drilled wells; and geophysical logs from 3 well sites. This report describes what was accomplished during phase 2 of the study, provides the data collected, and presents the approaches to strengthen relations between evapotranspiration rates measured at micrometeorological stations and spatially distributed groundwater discharge. This report also presents the approach to improve delineation of areas of groundwater discharge and describes the current methodology used to improve the accuracy of spatially distributed groundwater discharge rates in the Diamond Valley flow system.

Knochenmus, Lari A.; Berger, David L.; Moreo, Michael T.; Smith, J. LaRue

2011-01-01

331

Hydrochemistry of the Mahomet Bedrock Valley Aquifer, East-Central Illinois: indicators of recharge and ground-water flow  

USGS Publications Warehouse

A conceptual model of the ground-water flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA), east-central Illinois, was developed using major ion chemistry and isotope geochemistry. The MVA is a 'basal' fill in the east-west trending buried bedrock valley composed of clean, permeable sand and gravel to thicknesses of up to 61 m. It is covered by a thick sequence of glacial till containing thinner bodies of interbedded sand and gravel. Ground water from the MVA was found to be characterized by clearly defined geochemical regions with three distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west. Ground water in the Onarga Valley, a northeastern tributary of the MVA, is of two types, a mixed cation-SO42- type and a mixed cation-HCO3- type. The ground water is enriched in Na+, Ca2+, Mg2+, and SO42- which appears to be the result of an upward hydraulic gradient and interaction of deeper ground water with oxidized pyritic coals and shale. We suggest that recharge to the Onarga Valley and overlying aquifers is 100% from bedrock (leakage) and lateral flow from the MVA to the south. The central MVA (south of the Onarga Valley) is composed of relatively dilute ground water of a mixed cation-HCO3- type, with low total dissolved solids, and very low concentrations of Cl- and SO42-. Stratigraphic relationships of overlying aquifers and ground-water chemistry of these and the MVA suggest recharge to this region of the MVA (predominantly in Champaign County) is relatively rapid and primarily from the surface. Midway along the westerly flow path of the MVA (western MVA), ground water is a mixed cation-HCO3- type with relatively high Cl-, where Cl- increases abruptly by one to ??? two orders of magnitude. Data suggest that the increase in Cl- is the result of leakage of saline ground water from bedrock into the MVA. Mass-balance calculations indicate that approximately 9.5% of recharge in this area is from bedrock. Concentrations of Na+, HCO3-, As, and TDS also increase in the western MVA. Ground water in the MAK is of a Ca2+-HCO3- type. Mass-balance calculations, using Cl- as a natural, conservative tracer, indicate that approximately 17% of the ground water flowing from the confluence area is derived from the MVA.

Panno, S.V.; Hackley, K.C.; Cartwright, K.; Liu, C.-L.

1994-01-01

332

Fjord-valley fill stratigraphy from onshore high-resolution shear-wave seismics, Trondheim harbour area, central Norway  

NASA Astrophysics Data System (ADS)

To obtain information on the stratigraphic variability within the underlying fjord-valley fill, a shallow, shear-wave reflection seismic survey was successfully carried out on land in the Trondheim harbor area, central Norway. Since the last deglaciation, the region has been subjected to a fall of relative sea level of totally 175 m due to glacioisostatic rebound. The relative sea-level fall was accompanied by river erosion of emerging (glacio) marine deposits, several, large landslides, and delta progradation into the fjord. The infilled harbour area is located on the submerged part of a delta plain, and land reclamation is still going on. Historic and older submarine landslides are known to have taken place along the shoreline and an improved understanding of the ground conditions is therefore valuable for engineering purposes. In addition, the unique, S-wave seismic record gives insight into the overall architecture and long-term development of a fjord-valley filling influenced by relative sea level fall accompanied by occasional major mass-wasting events. Shear-wave reflection seismics was applied using a land streamer of 120 channels combined with a newly developed shear-wave vibrator from LIAG. Overall, 4.2 profile-km were acquired in a 2.5-D grid along paved roads and parking lots during night to minimize environmental noise. The investigations achieved a highly resolved image of the fjord-valley fill and clear bedrock detection. Vertical resolution is within a few meters over the entire profile whereas horizontal resolution decreases with depth. The entire fjord-valley fill is up to 160 m thick and five main stratigraphic units have been identified including bedrock. The fjord-valley fill is interpreted as consisting of glaciomarine deposits overlain by marine fjord sediments grading upwards into deltaic deposits. The change from continuous to more discontinuous or irregular reflection patterns reflects a progressive influence of delta-derived processes and mass-wasting during progradation of the shoreline. The seismic sections also indicate the presence of erosional surfaces such as scours or slide scars, and localized sediment accumulations such as landslide debris or the deposits of more diluted flows. The fjord-valley succession is draped by anthropogenic fill. Existing drill-hole data and seismic data offshore help to constrain the interpretation of the shear-wave seismic data. However, deeper and more targeted cores are needed to validate the geophysical and geological model. It is shown that the S-wave method has a great potential for the investigation of a fjord-valley stratigraphy even on man-made fills.

Hansen, L.; Polom, U.; L'Heureux, J.; Sauvin, G.; Lecomte, I.; Krawczyk, C. M.; Longva, O.

2009-12-01

333

Facies analysis of Tertiary basin-filling rocks of the Death Valley regional ground-water system and surrounding areas, Nevada and California  

USGS Publications Warehouse

Existing hydrologic models of the Death Valley region typically have defined the Cenozoic basins as those areas that are covered by recent surficial deposits, and have treated the basin-fill deposits that are concealed under alluvium as a single unit with uniform hydrologic properties throughout the region, and with depth. Although this latter generalization was known to be flawed, it evidently was made because available geologic syntheses did not provide the basis for a more detailed characterization. As an initial attempt to address this problem, this report presents a compilation and synthesis of existing and new surface and subsurface data on the lithologic variations between and within the Cenozoic basin fills of this region. The most permeable lithologies in the Cenozoic basin fills are freshwater limestones, unaltered densely welded tuffs, and little-consolidated coarse alluvium. The least permeable lithologies are playa claystones, altered nonwelded tuffs, and tuffaceous and clay-matrix sediments of several types. In all but the youngest of the basin fills, permeability probably decreases strongly with depth owing to a typically increasing abundance of volcanic ash or clay in the matrices of the clastic sediments with increasing age (and therefore with increasing depth in general), and to increasing consolidation and alteration (both hydrothermal and diagenetic) with increasing depth and age. This report concludes with a categorization of the Cenozoic basins of the Death Valley region according to the predominant lithologies in the different basin fills and presents qualitative constraints on the hydrologic properties of these major lithologic categories.

Sweetkind, Donald S.; Fridrich, Christopher J.; Taylor, Emily

2001-01-01

334

Facies Analysis of Tertiary Basin-Filling Rocks of the Death Valley Regional Ground-Water System and Surrounding Areas, Nevada and California  

SciTech Connect

Existing hydrologic models of the Death Valley region typically have defined the Cenozoic basins as those areas that are covered by recent surficial deposits, and have treated the basin-fill deposits that are concealed under alluvium as a single unit with uniform hydrologic properties throughout the region, and with depth. Although this latter generalization was known to be flawed, it evidently was made because available geologic syntheses did not provide the basis for a more detailed characterization. As an initial attempt to address this problem, this report presents a compilation and synthesis of existing and new surface and subsurface data on the lithologic variations between and within the Cenozoic basin fills of this region. The most permeable lithologies in the Cenozoic basin fills are freshwater limestones, unaltered densely welded tuffs, and little-consolidated coarse alluvium. The least permeable lithologies are playa claystones, altered nonwelded tuffs, and tuffaceous and cl ay-matrix sediments of several types. In all but the youngest of the basin fills, permeability probably decreases strongly with depth owing to a typically increasing abundance of volcanic ash or clay in the matrices of the clastic sediments with increasing age (and therefore with increasing depth in general), and to increasing consolidation and alteration (both hydrothermal and diagenetic) with increasing depth and age. This report concludes with a categorization of the Cenozoic basins of the Death Valley region according to the predominant lithologies in the different basin fills and presents qualitative constraints on the hydrologic properties of these major lithologic categories.

Sweetkind, D.S.; Fridrich, C.J.; Taylor, Emily

2002-04-04

335

Update to the Ground-Water Withdrawals Database for the Death Valley REgional Ground-Water Flow System, Nevada and California, 1913-2003  

SciTech Connect

Ground-water withdrawal estimates from 1913 through 2003 for the Death Valley regional ground-water flow system are compiled in an electronic database to support a regional, three-dimensional, transient ground-water flow model. This database updates a previously published database that compiled estimates of ground-water withdrawals for 19131998. The same methodology is used to construct each database. Primary differences between the 2 databases are an additional 5 years of ground-water withdrawal data, well locations in the updated database are restricted to Death Valley regional ground-water flow system model boundary, and application rates are from 0 to 1.5 feet per year lower than original estimates. The lower application rates result from revised estimates of crop consumptive use, which are based on updated estimates of potential evapotranspiration. In 2003, about 55,700 acre-feet of ground water was pumped in the DVRFS, of which 69 percent was used for irrigation, 13 percent for domestic, and 18 percent for public supply, commercial, and mining activities.

Michael T. Moreo; and Leigh Justet

2008-07-02

336

A three-dimensional numerical model of predevelopment conditions in the Death Valley regional ground-water flow system, Nevada and California  

USGS Publications Warehouse

In the early 1990's, two numerical models of the Death Valley regional ground-water flow system were developed by the U.S. Department of Energy. In general, the two models were based on the same basic hydrogeologic data set. In 1998, the U.S. Department of Energy requested that the U.S. Geological Survey develop and maintain a ground-water flow model of the Death Valley region in support of U.S. Department of Energy programs at the Nevada Test Site. The purpose of developing this 'second-generation' regional model was to enhance the knowledge an understanding of the ground-water flow system as new information and tools are developed. The U.S. Geological Survey also was encouraged by the U.S. Department of Energy to cooperate to the fullest extent with other Federal, State, and local entities in the region to take advantage of the benefits of their knowledge and expertise. The short-term objective of the Death Valley regional ground-water flow system project was to develop a steady-state representation of the predevelopment conditions of the ground-water flow system utilizing the two geologic interpretations used to develop the previous numerical models. The long-term objective of this project was to construct and calibrate a transient model that simulates the ground-water conditions of the study area over the historical record that utilizes a newly interpreted hydrogeologic conceptual model. This report describes the result of the predevelopment steady-state model construction and calibration. The Death Valley regional ground-water flow system is situated within the southern Great Basin, a subprovince of the Basin and Range physiographic province, bounded by latitudes 35 degrees north and 38 degrees 15 minutes north and by longitudes 115 and 118 degrees west. Hydrology in the region is a result of both the arid climatic conditions and the complex geology. Ground-water flow generally can be described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the flow system, ground water flows through zones of high transmissivity that have resulted from regional faulting and fracturing. The conceptual model of the Death Valley regional ground-water flow system used for this study is adapted from the two previous ground-water modeling studies. The three-dimensional digital hydrogeologic framework model developed for the region also contains elements of both of the hydrogeologic framework models used in the previous investigations. As dictated by project scope, very little reinterpretation and refinement were made where these two framework models disagree; therefore, limitations in the hydrogeologic representation of the flow system exist. Despite limitations, the framework model provides the best representation to date of the hydrogeologic units and structures that control regional ground-water flow and serves as an important information source used to construct and calibrate the predevelopment, steady-state flow model. In addition to the hydrogeologic framework, a complex array of mechanisms accounts for flow into, through, and out of the regional ground-water flow system. Natural discharges from the regional ground-water flow system occur by evapotranspiration, springs, and subsurface outflow. In this study, evapotranspiration rates were adapted from a related investigation that developed maps of evapotranspiration areas and computed rates from micrometeorological data collected within the local area over a multiyear period. In some cases, historical spring flow records were used to derive ground-water discharge rates for isolated regional springs. For this investigation, a process-based, numerical model was developed to estimat

D'Agnese, Frank A.; O'Brien, G. M.; Faunt, C.C.; Belcher, W.R.; San Juan, C.

2002-01-01

337

Significance of orthogonal flow in the Funeral Mountains metamorphic core complex, Death Valley, California: Insights from geochronology and microstructural analysis  

NASA Astrophysics Data System (ADS)

The Funeral Mountains metamorphic core complex (FMMCC) in Death Valley, California, exposes middle to lower crustal rocks of the Sevier-Laramide orogen in the footwall of the Boundary Canyon detachment (BCD). Monarch Canyon, located in the northwest section of the Funeral Mountains, exposes the structurally deepest rocks in the FMMCC. These Mesoproterozoic to Neoproterozoic metasedimentary rocks record upper amphibolite facies metamorphism with migmatites developed at the deepest levels. The Monarch Spring fault (MSF) juxtaposes migmatitic paragneisses below against pelitic schists, calcsilicate schists, and marbles above, and represents a deformed anatectic front. In the footwall of the BCD above the MSF, distributed ductile deformation and stratigraphically localized high-strain zones, termed intracore shear zones, are responsible for attenuation and local stratigraphic omission during top-northwest non-coaxial deformation. The relative contributions of Late Cretaceous-early Tertiary and Miocene extensional strains which manifest in the top-northwest fabrics remains unclear, and is being addressed by ongoing and combined thermochronologic, microstructural, and EBSD studies. Our working hypothesis is a polystage extensional history in the FMMCC, with Late Cretaceous extensional intracore shear zones locally reactivated during the Miocene. Below the MSF, migmatitic paragneisses lack similar greenschist to lower amphibolite facies top-northwest fabrics. These rocks instead exhibit heterogeneous strain and a weak to moderately developed northeast-trending mineral lineation, and a local, strong fabric asymmetry indicative of a top-southwest sense of shear. We propose that the anatectic front is an apparent zone of structural decoupling between top-southwest shear below and top-northwest shear above the MSF. Structural and geochronologic studies are currently underway to establish whether the orthogonally directed flow above and below the anatectic front were coeval or developed in sequence with a progressive change in kinematics. Preliminary zircon U-Pb geochronology on leucogranite dikes and sills provide constraints on the timing of top-southwest shearing in paragneisses below the MSF. In lower Monarch Canyon, a strongly deformed pegmatitic muscovite granite sill that is folded with the surrounding rock provides an age of 68.1 0.3 Ma. A weakly deformed leucogranite dike in upper Monarch Canyon yields an age of 61.1 0.8 Ma, and an undeformed leucogranite dike that cross cuts the top-southwest fabric as well as the folded sills in lower Monarch Canyon yields an age of 57.2 0.9 Ma. These ages suggest that this phase of deformation below the MSF began after ~68 Ma, was in its waning stages at ~61 Ma, and had ceased by ~57 Ma. Currently, there are few constraints on the timing of top-northwest shearing above the MSF. If the top-northwest and top-southwest fabrics are determined to be coeval, we will test if the contact represents a distributed zone of decoupling or an attachment zone.

Sauer, K. M.; Wells, M. L.; Hoisch, T. D.

2013-12-01

338

Visualizing and Analyzing Geologic and Hydrologic Models of the Death Valley Regional Ground-water Flow System, Nevada and California  

NASA Astrophysics Data System (ADS)

Numerical modeling of the Death Valley regional ground-water flow system, Nevada and California, involves the conceptualization and simulation of a complex and heterogeneous geologic and hydrologic system. The hydrogeologic characteristics of the region result from an arid climate and complex geology. Interbasin regional ground-water flow occurs through a thick Paleozoic carbonate-rock sequence, a locally thick Tertiary volcanic-rock sequence, and basin-fill alluvium. Throughout the system, deep and shallow ground-water flow may be controlled by extensive and pervasive faults and fractures. Understanding ground-water flow requires the formulation of conceptual and digital models that characterize the three-dimensional (3D) hydrogeologic framework within which the water moves. Part of this study includes the construction of a digital 3D geologic model that provides a description of the geometry and composition of the hydrogeologic units and structures that control ground-water flow. These hydrogeologic units and structures are then simulated in the hydrologic model using the Hydrogeologic Unit Flow (HUF) Package and the Horizontal-Flow Barrier (HFB) Package of the ground-water modeling code MODFLOW-2000. The HUF Package allows the geometry of the hydrogeologic units to be defined explicitly using hydrogeologic units that can be different from the defined flow-model layers. The HFB Package allows the simulation of features that retard flow. Likewise, zone and multiplication arrays can be utilized to incorporate hydraulic property detail, such as facies changes within a particular unit. Utilizing these capabilities significantly contributes to the ability of the modeler to better simulate the hydrogeologic conceptual model of the flow system. As geologic and hydrologic modeling software increase in complexity, modelers have the ability to better visualize and interact with the simulated hydrogeologic system and flow-model results. Post-processing utilities such as MODPATH and ZONEBUDGET allow the calculation of information helpful for analyzing the vast quantities of data. New and existing geographic information system (GIS) techniques can be used to visualize these results, such as flow paths and water-budget data, as well as water-level altitudes, hydrogeologic units, zone arrays, and flow-model layers. For example, three-dimensional views of particle paths along with the geometry of hydrogeologic units and structures provide insight into which features may be controlling ground-water flow paths. Employing GIS to develop maps of flux in and out of particular parts of the system aids in the visualization of the water budget. In addition, with the advent of the newer techniques and modeling tools the scientist can better explore the links between the hydrogeologic framework and the flow system. For instance, the scientist may conduct hypothesis testing regarding the hydraulic parameters associated with specific units or features based on visualizations analyses performed with the aid of GIS. Thus, the power of combining the GIS techniques and modeling packages is that, in addition to helping the scientist calibrate the ground-water model, it allows the scientist to test the degree to which the flow-model results match the conceptual model.

Faunt, C. C.; San Juan, C.

2003-12-01

339

Historical estimates of spatial reference evapotranspiration for the Central Valley of California  

NASA Astrophysics Data System (ADS)

In this study we present spatial reference evapotranspiration (ETo) estimates for the Central Valley from 1921 to 2008 derived from NCDC/NOAA daily climate data and PRISM monthly climate data grids (PRISM group; Oregon State University, Corvallis, USA; http://www.prism.oregonstate.edu). Data from the California Irrigation Management Information System (CIMIS) weather station were also used. 2009 is currently the third year of drought in California and better tools for irrigation and water resource management are needed to provide a secure water supply in the future. Temperature and Precipitation are driving variables in the estimation of ET occurring on the landscape scale. Consequently, modeling evaluations of a growing number of hydrological issues are increasingly requiring reliable area coverage of meteorological datasets. The availability of these datasets with adequate spatial and temporal resolution is particularly critical for decision support models for better management of water resources, such as the SIMETAW-II project supported with this study. Daily maximum-minimum temperature and precipitation spatial datasets were calculated by combining daily NCDC climate station data and monthly PRISM climate data grids. This study relies on the input PRISM grids to reproduce spatial climate patterns as well as anchor the daily climate values to the monthly averages given in the PRISM dataset such as total monthly precipitation and average daily temperatures. The historic daily climate data available for the period from 1921 to present consists of data for minimum temperature, maximum temperature and precipitation. Due to this restricted historical data set we cannot directly compute Penman-Monteith Reference Evapotranspiration (ETo) as adopted by the Environmental Water Resources Institute - American Society of Civil Engineers (ASCE-EWRI, 2004). Instead this study uses the Hargreaves-Samani equation for estimating Reference Evapotranspiration (ETh). For the final ETo estimates, we developed a correction factor based on CIMIS station ETo data and ETh data calculated from NCDC/NOAA COOP station data. Results from our study were validated against spatial ETo estimates by the CIMIS-GOES project from 2005 to present.

Falk, M.; Snyder, R. L.; Orang, M.; Hayes, S.

2009-12-01

340

Genesis of a till/sand breccia (Pleistocene, Note? Valley near Atanazyn, central Poland)  

NASA Astrophysics Data System (ADS)

The study area in Atanazyn in Note? Valley, NW Poland, is located on the surface of terrace III in Toru?-Eberswalde ice-marginal valley. Terrace III is correlated with the Pomeranian Phase and the Oldest Dryas, during which most of the fluvio-periglacial sedimentation in the Note? Valley took place. Four units are distinguished in the terrace: (1) horizontally stratified, ripple-drift cross-laminated and massive sand (unit Sh, Src, Sm) deposited in a shallow, sand-bed channel with a low-energy current; (2) a unique till/sand breccia formed by disintegration of a lodgement till due to drying out and frost activity under periglacial conditions, which was fluvially transported over a short distance; (3) a massive gravelly diamicton (DGm) representing a subaerial, cohesive debris flow; and (4) sand with low-angle cross-stratification (Sl) forming a coversand layer over the terrace. The presence of the till/sand breccia, which is unique for Quaternary sediments, sheds new light on the depositional conditions in ice-marginal valleys. The till/sand breccia lithofacies can be considered to be a diagnostic criterion for fluvio-periglacial conditions in ice-marginal valleys.

Pisarska-Jamro?y, Ma?gorzata; Zieli?ski, Tomasz

2011-05-01

341

Geographical allozymes differentiation in wild Phaseolus lunatus L. of the Central Valley of Costa Rica and its implications for conservation and management of populations  

Microsoft Academic Search

To suggest a conservation and management strategy for wild Lima bean (Phaseolus lunatus L.) in the Central Valley of Costa Rica, we examined the spatial distribution of genetic variation in 96 populations, using ten enzyme loci to analyse F-statistics and Moran?s I. These loci displayed 20 alleles, of which 5 with relatively high frequencies were exclusively localised in the central

Arsne Iri Zoro Bi; Jean-Pierre Baudoin

342

Burial and preservation of a 30,000 year old perennial snowbank in Red Creek valley, Ogilvie Mountains, central Yukon, Canada  

Microsoft Academic Search

This study describes the origin and age of a body of massive ground ice exposed in the headwall of a thaw slump in the Red Creek valley, central Yukon, Canada. The site is located beyond the limits of Pleistocene glaciation in central Yukon and within the southern limit of the modern continuous permafrost zone. The origin of the massive ground

Denis Lacelle; Melanie St-Jean; Bernard Lauriol; Ian D. Clark; Antoni Lewkowicz; Duane G. Froese; Stephen C. Kuehn; Grant Zazula

2009-01-01

343

Spatial use by wintering greater white-fronted geese relative to a decade of habitat change in California's Central Valley  

USGS Publications Warehouse

We investigated the effect of recent habitat changes in California's Central Valley on wintering Pacific greater white-fronted geese (Anser albifrons frontalis) by comparing roost-to-feed distances, distributions, population range sizes, and habitat use during 1987-1990 and 1998-2000. These habitat changes included wetland restoration and agricultural land enhancement due to the 1990 implementation of the Central Valley Joint Venture, increased land area used for rice (Oryza sativa) production, and the practice of flooding, rather than burning, rice straw residues for decomposition because of burning restrictions enacted in 1991. Using radiotelemetry, we tracked 192 female geese and recorded 4,516 locations. Geese traveled shorter distances between roosting and feeding sites during 1998-2000 (24.2 ?? 2.2 km) than during 1987-1990 (32.5 ?? 3.4 km); distance traveled tended to decline throughout winter during both decades and varied among watershed basins. Population range size was smaller during 1998-2000 (3,367 km2) than during 1987-1990 (5,145 km2), despite a 2.2-fold increase in the size of the Pacific Flyway population of white-fronted geese during the same time period. The population range size also tended to increase throughout winter during both decades. Feeding and roosting distributions of geese also differed between decades; geese shifted into basins that had the greatest increases in the amount of area in rice production (i.e., American Basin) and out of other basins (i.e., Delta Basin). The use of rice habitat for roosting (1987-1990: 40%, 1998-2000: 54%) and feeding (1987-1990: 57%, 1998-2000: 72%) increased between decades, whereas use of wetlands declined for roosting (1987-1990: 36%, 1998-2000: 31%) and feeding (1987-1990: 22%, 1998-2000: 12%). Within postharvested rice habitats, geese roosted and fed primarily in burned rice fields during 1987-1990 (roost: 43%, feed: 34%), whereas they used flooded rice fields during 1998-2000 (roost: 78%, feed: 64%). Our results suggest that white-fronted geese have altered their spatial use of California's Central Valley during the past decade in response to changing agricultural practices and the implementation of the Central Valley Joint Venture.

Ackerman, J.T.; Takekawa, J.Y.; Orthmeyer, D.L.; Fleskes, J.P.; Yee, J.L.; Kruse, K.L.

2006-01-01

344

Effectiveness and Tradeoffs between Portfolios of Adaptation Strategies Addressing Future Climate and Socioeconomic Uncertainties in California's Central Valley  

NASA Astrophysics Data System (ADS)

The Central Valley of California is one of the major agricultural areas in the United States. The Central Valley Project (CVP) is operated by the Bureau of Reclamation to serve multiple purposes including generating approximately 4.3 million gigawatt hours of hydropower and providing, on average, 5 million acre-feet of water per year to irrigate approximately 3 million acres of land in the Sacramento, San Joaquin, and Tulare Lake basins, 600,000 acre-feet per year of water for urban users, and 800,000 acre-feet of annual supplies for environmental purposes. The development of effective adaptation and mitigation strategies requires assessing multiple risks including potential climate changes as well as uncertainties in future socioeconomic conditions. In this study, a scenario-based analytical approach was employed by combining three potential 21st century socioeconomic futures with six representative climate and sea level change projections developed using a transient hybrid delta ensemble method from an archive of 112 bias corrected spatially downscaled CMIP3 global climate model simulations to form 18 future socioeconomic-climate scenarios. To better simulate the effects of climate changes on agricultural water demands, analyses of historical agricultural meteorological station records were employed to develop estimates of future changes in solar radiation and atmospheric humidity from the GCM simulated temperature and precipitation. Projected changes in atmospheric carbon dioxide were computed directly by weighting SRES emissions scenarios included in each representative climate projection. These results were used as inputs to a calibrated crop water use, growth and yield model to simulate the effects of climate changes on the evapotranspiration and yields of major crops grown in the Central Valley. Existing hydrologic, reservoir operations, water quality, hydropower, greenhouse gas (GHG) emissions and both urban and agricultural economic models were integrated into a suite of decision support tools to assess the impacts of future socioeconomic-climate uncertainties on key performance metrics for the CVP, State Water Project and other Central Valley water management systems under current regulatory requirements. Four thematic portfolios consisting of regional and local adaptation strategies including changes in reservoir operations, increased water conservation, storage and conveyance were developed and simulated to evaluate their potential effectiveness in meeting delivery reliability, water quality, environmental, hydropower, GHG, urban and agricultural economic performance criteria. The results indicate that the portfolios exhibit a considerable range of effectiveness depending on the socioeconomic-climate scenario. For most criteria, the portfolios were more sensitive to climate projections than socioeconomic assumptions. However, the results demonstrate that important tradeoffs occur between portfolios depending on the performance criteria considered.

Tansey, M. K.; Van Lienden, B.; Das, T.; Munevar, A.; Young, C. A.; Flores-Lopez, F.; Huntington, J. L.

2013-12-01

345

New geochronological, paleoclimatological, and archaeological data from the Narmada Valley hominin locality, central India.  

PubMed

The oldest known fossil hominin in southern Asia was recovered from Hathnora in the Narmada Basin, central India in the early 1980's. Its age and taxonomic affinities, however, have remained uncertain. Current estimates place its maximum age at >236ka, but not likely older than the early middle Pleistocene. The calvaria, however, could be considerably younger. We report recent fieldwork at Hathnora and associated Quaternary type-sections that has provided new geological and archaeological insights. The portion of the exposed 'Boulder Conglomerate' within the Surajkund Formation, which forms a relict terrace and has yielded the hominin fossils, contains reworked and stylistically mixed lithic artifacts and temporally mixed fauna. Three mammalian teeth stratigraphically associated with the hominin calvaria were dated by standard electron spin resonance (ESR). Assuming an early uranium uptake (EU) model for the teeth, two samples collected from the reworked surface deposit averaged 49+/-1ka (83+/-2ka, assuming linear uptake [LU]; 196+/-7ka assuming recent uptake [RU]). Another sample recovered from freshly exposed, crossbedded gravels averaged 93+/-5ka (EU), 162+/-8ka (LU) or 407+/-21ka (RU). While linear uptake models usually provide the most accurate ages for this environment and time range, the EU ages represent the minimum possible age for fossils in the deposit. Regardless, the fossils are clearly reworked and temporally mixed. Therefore, the current data constrains the minimum possible age for the calvaria to 49+/-1ka, although it could have been reworked and deposited into the Hathnora deposit any time after 160ka (given the LU uptake ages) or earlier (given the RU ages). At Hathnora, carbonaceous clay, bivalve shells, and a bovid tooth recovered from layers belonging to the overlying Baneta Formation have yielded (14)C ages of 35.66+/-2.54cal ky BP, 24.28+/-0.39cal ky BP, and 13.15+/-0.34ky BP, respectively. Additional surveys yielded numerous lithics and fossils on the surface and within the stratigraphic sequence. At the foot of the Vindhyan Hills 2km from the river, we recovered a typologically Early Acheulean assemblage comprised of asymmetrical bifaces, large cleavers with minimal working, trihedral picks, and flake tools in fresh condition. These tools may be the oldest Acheulean in the Narmada Valley. Several lithics recovered from the Dhansi Formation may represent the first unequivocal evidence for an early Pleistocene hominin presence in India. In situ invertebrate and vertebrate fossils, pollen, and spores indicate a warm, humid climate during the late middle Pleistocene. High uranium concentrations in the mammalian teeth indicate exposure to saline water, suggesting highly evaporative conditions in the past. Late Pleistocene sediment dated between 24.28+/-0.39cal ky BP and 13.15+/-340ky BP has yielded pollen and spores indicating cool, dry climatic conditions corresponding to Oxygen Isotope Stage 2 (OIS 2). An early Holocene palynological assemblage from the type locality at Baneta shows evidence for relatively dry conditions and a deciduous forest within the region. The Dhansi Formation provisionally replaces the Pilikarar Formation as the oldest Quaternary formation within the central Narmada Basin. The Baneta Formation, previously dated at 70ka to 128ka, correlates with the late Pleistocene and early Holocene. Our results highlight the need for further Quaternary geological and paleoanthropological research within the Narmada Basin, especially because dam construction threatens these deposits. PMID:19118867

Patnaik, Rajeev; Chauhan, Parth R; Rao, M R; Blackwell, B A B; Skinner, A R; Sahni, Ashok; Chauhan, M S; Khan, H S

2009-02-01

346

Depositional environments and sedimentary tectonics of subsurface Cotton Valley group (upper Jurassic), west-central Mississippi  

Microsoft Academic Search

Study of data from 65 selected wells in a 6-county area (about 60 by 60 mi) north and west of Jackson, Mississippi, discloses that Cotton Valley strata, now within the axial trough of the Mississippi embayment, display thickness variations which demonstrate that Late Jurassic sedimentation was strongly controlled by maximum subsidence along the same trough axis. Examination of well logs,

B. D. Jr. Sydboten; R. L. Bowen

1987-01-01

347

GROUNDWATER AND STRATIGRAPHY IN TWO VALLEY BOTTOM WETLANDS CENTRAL PIEDMONT, VIRGINIA, USA  

E-print Network

-use history in controlling the role of groundwater and overbank flow in valley-bottom wetlands. The expected sequence often contain numerous riparian wetlands fed by rain, groundwater and overbank flow in the silty millpond sediments. This complex history of deposition, incision and piping created terrace

Darby, Dennis

348

Runoff simulation in the Ferghana Valley (Central Asia) using conceptual hydrological HBV-light model  

NASA Astrophysics Data System (ADS)

Glaciers and permafrost on the ranges of the Tien Shan mountain system are primary sources of water in the Ferghana Valley. The water artery of the valley is the Syr Darya River that is formed by confluence of the Naryn and Kara Darya rivers, which originate from the mountain glaciers of the Ak-Shyrak and the Ferghana ranges accordingly. The Ferghana Valley is densely populated and main activity of population is agriculture that heavily depends on irrigation especially in such arid region. The runoff reduction is projected in future due to global temperature rise and glacier shrinkage as a consequence. Therefore, it is essential to study climate change impact on water resources in the area both for ecological and economic aspects. The evaluation of comparative contribution of small upper catchments (n=24) with precipitation predominance in discharge and the large Naryn and Karadarya River basins, which are fed by glacial melt water, to the Fergana Valley water balance under current and future climatic conditions is general aim of the study. Appropriate understanding of the hydrological cycle under current climatic conditions is significant for prognosis of water resource availability in the future. Thus, conceptual hydrological HBV-light model was used for analysing of the water balance of the small upper catchments that surround the Ferghana Valley. Three trial catchments (the Kugart River basin, 1010 km; the Kurshab River basin, 2010 km2; the Akbura River basin, 2260 km) with relatively good temporal quality data were chosen to setup the model. Due to limitation of daily temperature data the MODAWEC weather generator, which converts monthly temperature data into daily based on correlation with rainfall, was tested and applied for the HBV-light model.

Radchenko, Iuliia; Breuer, Lutz; Forkutsa, Irina; Frede, Hans-Georg

2013-04-01

349

Paleomagnetic evidence for the age and extent of middle Tertiary counterclockwise rotation, Dixie Valley region, west central Nevada  

USGS Publications Warehouse

Paleomagnetic data obtained from Oligocene to lower Miocene igneous rocks and middle Miocene basaltic rocks of fifteen localities from a region surrounding Dixie Valley in west central Nevada indicate that parts of the area experienced counterclockwise vertical-axis rotation, and these data provide constraints on the extent and timing of rotation. Counterclockwise vertical-axis rotation probably exceeding 30?? is indicated for Oligocene to lower Miocene rocks in the central part of the study area. Paleomagnetic data indicate that Oligocene to lower Miocene rocks at some localities in the northern and southern parts of the study area (e.g., the Golconda Canyon locality) probably did not experience significant Tertiary counterclockwise rotation. -from Authors

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

1991-01-01

350

Chemical and nutritional composition of tejate, a traditional maize and cacao beverage from the Central Valleys of Oaxaca, Mexico.  

PubMed

Foam-topped cacao and maize beverages have a long history in Mesoamerica. Tejate is such a beverage found primarily in the Zapotec region of the Central Valleys of Oaxaca, Mexico. Historically tejate has been ceremonially important but also as an essential staple, especially during periods of hard fieldwork. However, the nutritional contribution of traditional foods such as tejate has not been investigated. We analyzed tejate samples from three Central Valley communities, vendors in urban Oaxaca markets and one migrant vendor in California, USA for their proximate composition, amino acid content and scores, and mineral and methylxanthine content. Nutritional and chemical variation exists among tejate recipes, however, the beverage is a source of energy, fat, methylxanthines, K, Fe and other minerals although their availability due to presence of phytates remains to be determined. Tejate is a source of protein comparable to an equal serving size of tortillas, with protein quality similarly limited in both. Tejate provides the nutritional benefits of maize, and some additional ones, in a form appealing during hot periods of intense work, and year round because of its cultural significance. Its substitution by sodas and other high glycemic beverages may have negative nutritional, health and cultural consequences. PMID:22407326

Sotelo, Angela; Soleri, Daniela; Wacher, Carmen; Snchez-Chinchillas, Argelia; Argote, Rosa Maria

2012-06-01

351

Single-Station Passive Seismic Stratigraphy for the characterization of subsurface structure of the Valtellina valley (central Alps, northern Italy)  

NASA Astrophysics Data System (ADS)

The reconstruction of the subsurface structure of alpine valleys plays a key-role in the evaluation of their genesis, entrenchment and tectonic evolution. As a matter of fact, their characterization is strictly dependent on borehole data (water wells, shallow geognostic logs) and land based, deep seismic reflection/refraction lines; unfortunately, the availability of these datasets is often limited by economic and logistical limitations. In this work the subsurface structure of the Valtellina buried valley (central Alps, northern Italy) was investigated by the means of Single-Station Passive Seismic Stratigraphy (S-SPSS), which yields the 1D shear velocity (Vs) profiles, based on the Horizontal to Vertical Spectral Ratios (HVSR) of microtremors produced by Raleigh waves trapped in the ground and provided by measurements of the resonance frequencies produced by a layered seismic stratigraphy. The study area is the central part of Valtellina, W-E oriented along the Insubric line and drained by the Adda river. The sedimentary succession is known by shallow (

Mele, M.; Bini, A.; Bassi, S.; Giudici, M.; Monti, M.; Azzola, M.

2012-04-01

352

Central California Valley Ecoregion: Chapter 17 in Status and trends of land change in the Western United States--1973 to 2000  

USGS Publications Warehouse

The Central California Valley Ecoregion, which covers approximately 45,983 km2 (17,754 mi2), is an elongated basin extending approximately 650 km north to south through central California (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is surrounded entirely by the Southern and Central California Chaparral and Oak Woodlands Ecoregion, which includes parts of the Coast Ranges to the west and which is bounded by the Sierra Nevada to the east. The Central California Valley Ecoregion accounts for more than half of Californias agricultural production value and is one of the most important agricultural regions in the country, with flat terrain, fertile soils, a favorable climate, and nearly 70 percent of its land in cultivation (Kuminoff and others, 2000; Sumner and others, 2003). Commodities produced in the region include milk and dairy, cattle and calves, cotton, almonds, citrus, and grapes, among others (U.S. Department of Agriculture, 2004; Johnston and McCalla, 2004; Kuminoff and others, 2000) (figs. 2A,B,C). Six of the top eight agricultural-producing counties in California are located at least partly within the Central California Valley Ecoregion (Kuminoff and others, 2000) (table 1). The Central California Valley Ecoregion is also home to nearly 5 million people spread throughout the region, including the major cities of Sacramento (state capital), Fresno, Bakersfield, and Stockton, California (U.S. Census Bureau, 2000) (fig. 1).

Sleeter, Benjamin M.

2012-01-01

353

Wild food plants and wild edible fungi in two valleys of the Qinling Mountains (Shaanxi, central China)  

PubMed Central

Background The aim of the study was to investigate knowledge and use of wild food plants in two mountain valleys separated by Mount Taibai the highest peak of northern China and one of its biodiversity hotspots, each adjacent to species-rich temperate forest vegetation. Methods Seventy two free lists were collected among the inhabitants of two mountain valleys (36 in each). All the studied households are within walking distance of primary forest vegetation, however the valleys differed in access to urban centers: Houzhenzi is very isolated, and the Dali valley has easier access to the cities of central Shaanxi. Results Altogether, 185 wild food plant species and 17 fungi folk taxa were mentioned. The mean number of freelisted wild foods was very high in Houzhenzi (mean 25) and slightly lower in Dali (mean 18). An average respondent listed many species of wild vegetables, a few wild fruits and very few fungi. Age and male gender had a positive but very low effect on the number of taxa listed. Twelve taxa of wild vegetables (Allium spp., Amaranthus spp., Caryopteris divaricata, Helwingia japonica, Matteucia struthiopteris, Pteridium aquilinum, Toona sinensis, Cardamine macrophylla, Celastrus orbiculatus, Chenopodium album, Pimpinella sp., Staphylea bumalda &S. holocarpa), two species of edible fruits (Akebia trifoliata, Schisandra sphenanthera) and none of the mushrooms were freelisted by at least half of the respondents in one or two of the valleys. Conclusion The high number of wild vegetables listed is due to the high cultural position of this type of food in China compared to other parts of the world, as well as the high biodiversity of the village surroundings. A very high proportion of woodland species (42%, double the number of the ruderal species used) among the listed taxa is contrary to the general stereotype that wild vegetables in Asia are mainly ruderal species. The very low interest in wild mushroom collecting is noteworthy and is difficult to explain. It may arise from the easy access to the cultivated Auricularia and Lentinula mushrooms and very steep terrain, making foraging for fungi difficult. PMID:23587149

2013-01-01

354

Rise and tilt of metamorphic rocks in the lower plate of a detachment fault in the Funeral Mountains, Death Valley, California  

SciTech Connect

The authors attempt to integrate new and old observations on the Funeral Mountains, in Death Valley, California, into an integrated model of the evolution of the lower plate in this region. This area consists of a detachment fault. Much effort has been directed toward explaining the development of detachment faults. Extensive petrologic, geochronologic and mapping evidence had been developed. The authors combine thermobarometric data on unsheared metamorphic rock in this region, kinematic analysis of folding in the area, and new geochronologic data from fission track measurements, K-Ar and [sup 40]Ar/[sup 39]Ar dating measurements. Their conclusion is that the data supports the feature of models for detachment faulting which claim that a fault surface dips and undergoes a rotation to a horizontal orientation, accompanied by a comparable tilt of the lower plate. 64 refs., 19 figs., 4 tabs.

Hoisch, T.D. (Northern Arizona Univ., Flagstaff (United States)); Simpson, C. (Johns Hopkins Univ., Baltimore, MD (United States))

1993-04-10

355

Expert system-based mineral mapping in northern Death Valley, California/Nevada, using the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)  

NASA Technical Reports Server (NTRS)

Integrated analysis of imaging spectrometer data and field spectral measurements were used in conjunction with conventional geologic field mapping to characterize bedrock and surficial geology at the northern end of Death Valley, California and Nevada. A knowledge-based expert system was used to automatically produce image maps showing the principal surface mineralogy from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data. Linear spectral unmixing of the AVIRIS data allowed further determination of relative mineral, abundances and identification of mineral assemblages and mixtures. The imaging spectrometer data show the spatial distribution of spectrally distinct minerals occurring both as primary rockforming minerals and as alteration and weathering products. Field spectral measurements were used to verify the mineral maps and field mapping was used to extend the remote sensing results. Geographically referenced image maps produced from these data form new base maps from which to develop improved understanding of the processes of deposition and erosion affecting the present land surface.

Kruse, F. A.; Lefkoff, A. B.; Dietz, J. B.

1993-01-01

356

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies. LANDSAT TM investigation proposal TM-019  

NASA Technical Reports Server (NTRS)

Processing and interpretation of Thematic Mapper (TM) data, extensive field work, and processing of SPOT data were continued. Results of these analyses led to the testing and rejecting of several of the geologic/tectonic hypotheses concerning the continuation of the Garlock Fault Zone (GFZ). It was determined that the Death Valley Fault Zone (DVFZ) is the major through-going feature, extending at least 60 km SW of the Avawatz Mountains. Two 5 km wide fault zones were identified and characterized in the Soda and Bristol Mountains, forming a continuous zone of NW trending faulting. Geophysical measurements indicate a buried connection between the Avawatz and the Soda Mountains Fault Zone. Future work will involve continued field work and mapping at key locations, further analyses of TM data, and conclusion of the project.

Abrams, Michael; Verosub, Ken

1987-01-01

357

Cardiospecificity of the 3 rd generation cardiac troponin T assay during and after a 216 km ultra-endurance marathon run in Death Valley  

Microsoft Academic Search

Background\\u000a The reasons\\u000a for the appearance of cardiacspecific\\u000a troponin (cTnT) after\\u000a strenuous exercise are unclear. The\\u000a aim of the present study was to\\u000a evaluate the cardiospecificity of the\\u000a 3rd generation cardiac cTnT assay\\u000a during and after an ultra-endurance\\u000a race of 216 km at extreme\\u000a environmental conditions in Death\\u000a Valley.\\u000a \\u000a \\u000a \\u000a \\u000a Study design and methods\\u000a We measured serially cTnT, creatine\\u000a kinase (CK),

H. J. Roth; R. M. Leithuser; H. Doppelmayr; M. Doppelmayr; H. Finkernagel; S. P. von Duvillard; S. Korff; H. A. Katus; Evangelos Giannitsis; R. Beneke

2007-01-01

358

Study of LANDSAT-D thematic mapper performance as applied to hydrocarbon exploration. [Southern Ontario, Lawton, Oklahoma; Owl Creek, Wyoming; Washington, D.C.; and Death Valley California  

NASA Technical Reports Server (NTRS)

Improved delineation of known oil and gas fields in southern Ontario and a spectacularly high amount of structural information on the Owl Creek, Wyoming scene were obtained from analysis of TM data. The use of hue, saturation, and value image processing techniques on a Death Valley, California scene permitted direct comparison of TM processed imagery with existing 1:250,000 scale geological maps of the area and revealed small outcrops of Tertiary volcanic material overlying Paleozoic sections. Analysis of TM data over Lawton, Oklahoma suggests that the reducing chemical environment associated with hydrocarbon seepage change ferric iron to soluble ferrous iron, allowing it to be leached. Results of the band selection algorithm show a suprising consistency, with the 1,4,5 combination selected as optimal in most cases.

Everett, J. R. (principal investigator)

1983-01-01

359

Linear-Patterned Slopes in the Discontinuous Permafrost Zone of the Central Mackenzie River Valley  

Microsoft Academic Search

In the Mackenzie River Valley between Norman Wells and Fort Simpson a study of the character, dlstribution and orientation of gently-inclined, linear-patterned slopes revealed that most northeast-facing, lichen-covered slopes have permafrost within about 10-25 inches of the surface, and display evidence that cryoturbation was once operative in the active layer. Most lineated slopes without near-surface permafrost face southwest, are surficially

C. B. CRAMPTON

360

Cenozoic Tectonism in the Central Basin and Range: Motion of the Sierran-Great Valley Block  

Microsoft Academic Search

According to geologic reconstructions, the motion of the Sierran-Great Valley block with respect to the Colorado Plateau was mainly westerly at more than 20 mm\\/yr from 16 to 10 Ma, changing to northwest or NNW since 8 to 10 Ma, at an average rate of 15 mm\\/yr. These kinematics are consistent with two other independent methods of determining the position

Brian Wernicke; J. Kent Snow

1998-01-01

361

Habitat range of two alpine medicinal plants in a trans-Himalayan dry valley, Central Nepal  

Microsoft Academic Search

Understanding of the habitat range of threatened Himalayan medicinal plants which are declining in their abundance due to\\u000a high anthropogenic disturbances is essential for developing conservation strategies and agrotechnologies for cultivation.\\u000a In this communication, we have discussed the habitat range of two alpine medicinal plants, Aconitum naviculare (Brhl) Stapf and Neopicrorhiza scrophulariiflora (Pennel) Hong in a trans-Himalayan dry valley of

Bharat Babu Shrestha; Pramod Kumar Jha

2009-01-01

362

Using remote sensing and GIS techniques to estimate discharge and recharge fluxes for the Death Valley regional groundwater flow system, USA  

USGS Publications Warehouse

The recharge and discharge components of the Death Valley regional groundwater flow system were defined by techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were used to calculate discharge volumes for these area. An empirical method of groundwater recharge estimation was modified to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter estimation techniques also used these data to evaluate the reliability and sensitivity of estimated values.The recharge and discharge components of the Death Valley regional groundwater flow system were defined by remote sensing and GIS techniques that integrated disparate data types to develop a spatially complex representation of near-surface hydrological processes. Image classification methods were applied to multispectral satellite data to produce a vegetation map. This map provided a basis for subsequent evapotranspiration and infiltration estimations. The vegetation map was combined with ancillary data in a GIS to delineate different types of wetlands, phreatophytes and wet playa areas. Existing evapotranspiration-rate estimates were then used to calculate discharge volumes for these areas. A previously used empirical method of groundwater recharge estimation was modified by GIS methods to incorporate data describing soil-moisture conditions, and a recharge potential map was produced. These discharge and recharge maps were readily converted to data arrays for numerical modelling codes. Inverse parameter estimation techniques also used these data to evaluate the reliability and sensitivity of estimated values.

D'Agnese, F. A.; Faunt, C.C.; Turner, A.K.

1996-01-01

363

Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front  

USGS Publications Warehouse

Controversy exists over whether alluvial-fan sedimentation along tectonically active mountain fronts is driven by climatic changes or tectonics. Knowing the age of sedimentation is the key to understanding the relationship between sedimentation and its cause. Alluvial-fan deposits in Death Valley and throughout the arid southwestern United States have long been the subjects of study, but their ages have generally eluded researchers until recently. Most mapping efforts have recognized at least four major relative-age groupings (Q1 (oldest), Q2, Q3, and Q4 (youngest)), using observed changes in surface soils and morphology, relation to the drainage net, and development of desert pavement. Obtaining numerical age determinations for these morphologic stages has proven challenging. We report the first optically stimulated luminescence (OSL) ages for three of these four stages deposited within alluvial-fans along the tectonically active Black Mountains of Death Valley. Deposits showing distinct, remnant bar and swale topography (Q3b) have OSL ages from 7 to 4 ka., whereas those with moderate to poorly developed desert pavement and located farther above the active channel (Q3a) have OSL ages from 17 to 11 ka. Geomorphically older deposits with well-developed desert pavement (Q2d) have OSL ages ???25 ka. Using this OSL-based chronology, we note that alluvial-fan deposition along this tectonically active mountain front corresponds to both wet-to-dry and dry-to-wet climate changes recorded globally and regionally. These findings underscore the influence of climate change on alluvial fan deposition in arid and semi-arid regions. ?? 2007 Elsevier Ltd and INQUA.

Sohn, M.F.; Mahan, S.A.; Knott, J.R.; Bowman, D.D.

2007-01-01

364

Copper Canyon track locality (Pliocene) conservation strategies, Death Valley National Park, USA (Gestion et mise en valeur du site pistes pliocnes du Copper Canyon, Parc National de la \\  

Microsoft Academic Search

Copper Canyon within Death Valley National Park, California, USA, preserves literally hundreds of in situ fossil mammal and bird tracks spanning over 3000 meters of lacustrine Pliocene deposits. Management of the Copper Canyon track locality has included closure and photo-monitoring of the locality. Research currently underway will evaluate the photo-monitoring program and recommend set standards and protocols for in situ

Torrey NYBORG

365

Principal facts for gravity stations in the Antelope Valley-Bedell Flat area, west-central Nevada  

USGS Publications Warehouse

In April 2000 the U.S. Geological Survey (USGS) established 211 gravity stations in the Antelope Valley and Bedell Flat area of west-central Nevada (see figure 1). The stations were located about 15 miles north of Reno, Nevada, southwest of Dogskin Mountain, and east of Petersen Mountain, concentrated in Antelope Valley and Bedell Flat (figure 2). The ranges in this area primarily consist of normal-faulted Cretaceous granitic rocks, with some volcanic and metavolcanic rocks. The purpose of the survey was to characterize the hydrogeologic framework of Antelope Valley and Bedell Flat in support of future hydrologic investigations. The information developed during this study can be used in groundwater models. Gravity data were collected between latitude 3937.5' and 4000' N and longitude 11937.5' and 12000' W. The stations were located on the Seven Lakes Mountain, Dogskin Mountain, Granite Peak, Bedell Flat, Fraser Flat, and Reno NE 7.5 minute quadrangles. All data were tied to secondary base station RENO-A located on the campus of the University of Nevada at Reno (UNR) in Reno, Nevada (latitude 3932.30' N, longitude 11948.70' W, observed gravity value 979674.69 mGal). The value for observed gravity was calculated by multiple ties to the base station RENO (latitude 3932.30' N, longitude 11948.70' W, observed gravity value 979674.65 mGal), also on the UNR campus. The isostatic gravity map (figure 3) includes additional data sets from the following sources: 202 stations from a Geological Survey digital data set (Ponce, 1997), and 126 stations from Thomas C. Carpenter (written commun., 1998).

Jewel, Eleanore B.; Ponce, David A.; Morin, Robert L.

2000-01-01

366

Heat flow in Railroad Valley, Nevada and implications for geothermal resources in the south-central Great Basin  

USGS Publications Warehouse

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.

Williams, C.F.; Sass, J.H.

2006-01-01

367

Stable isotope and groundwater flow dynamics of agricultural irrigation recharge into groundwater resources of the Central Valley, California  

SciTech Connect

Intensive agricultural irrigation and overdraft of groundwater in the Central Valley of California profoundly affect the regional quality and availability of shallow groundwater resources. In the natural state, the {delta}{sup 18}O values of groundwater were relatively homogeneous (mostly -7.0 {+-} 0.5{per_thousand}), reflecting local meteoric recharge that slowly (1-3m/yr) flowed toward the valley axis. Today, on the west side of the valley, the isotope distribution is dominated by high {sup 18}O enclosures formed by recharge of evaporated irrigation waters, while the east side has bands of low {sup 18}O groundwater indicating induced recharge from rivers draining the Sierra Nevada mountains. Changes in {delta}{sup 18}O values caused by the agricultural recharge strongly correlate with elevated nitrate concentrations (5 to >100 mg/L) that form pervasive, non-point source pollutants. Small, west-side cities dependent solely on groundwater resources have experienced increases of >1.0 mg/L per year of nitrate for 10-30 years. The resultant high nitrates threaten the economical use of the groundwater for domestic purposes, and have forced some well shut-downs. Furthermore, since >80% of modern recharge is now derived from agricultural irrigation, and because modern recharge rates are {approximately}10 times those of the natural state, agricultural land retirement by urbanization will severely curtail the current safe-yields and promote overdraft pumping. Such overdrafting has occurred in the Sacramento metropolitan area for {approximately}40 years, creating cones of depression {approximately}25m deep. Today, groundwater withdrawal in Sacramento is approximately matched by infiltration of low {sup 18}O water (-11.0{per_thousand}) away from the Sacramento and American Rivers, which is estimated to occur at 100-300m/year from the sharp {sup 18}O gradients in our groundwater isotope map.

Davisson, M.L.; Criss, R.E.

1995-01-01

368

Comparison of sediment supply to San Francisco Bay from watersheds draining the Bay Area and the Central Valley of California  

USGS Publications Warehouse

Quantifying suspended sediment loads is important for managing the world's estuaries in the context of navigation, pollutant transport, wetland restoration, and coastal erosion. To address these needs, a comprehensive analysis was completed on sediment supply to San Francisco Bay from fluvial sources. Suspended sediment, optical backscatter, velocity data near the head of the estuary, and discharge data obtained from the output of a water balance model were used to generate continuous suspended sediment concentration records and compute loads to the Bay from the large Central Valley watershed. Sediment loads from small tributary watersheds around the Bay were determined using 235 station-years of suspended sediment data from 38 watershed locations, regression analysis, and simple modeling. Over 16 years, net annual suspended sediment load to the head of the estuary from its 154,000 km2 Central Valley watershed varied from 0.13 to 2.58 (mean = 0.89) million metric t of suspended sediment, or an average yield of 11 metric t/km2/yr. Small tributaries, totaling 8145 km2, in the nine-county Bay Area discharged between 0.081 and 4.27 (mean = 1.39) million metric t with a mean yield of 212 metric t/km2/yr. The results indicate that the hundreds of urbanized and tectonically active tributaries adjacent to the Bay, which together account for just 5% of the total watershed area draining to the Bay and provide just 7% of the annual average fluvial flow, supply 61% of the suspended sediment. The small tributary loads are more variable (53-fold between years compared to 21-fold for the inland Central Valley rivers) and dominated fluvial sediment supply to the Bay during 10 out of 16 yr. If San Francisco Bay is typical of other estuaries in active tectonic or climatically variable coastal regimes, managers responsible for water quality, dredging and reusing sediment accumulating in shipping channels, or restoring wetlands in the world's estuaries may need to more carefully account for proximal small urbanized watersheds that may dominate sediment supply.

McKee, L.J.; Lewicki, M.; Schoellhamer, D.H.; Ganju, N.K.

2013-01-01

369

Timing and extent of Holocene glaciations in the monsoon dominated Dunagiri valley (Bangni glacier), Central Himalaya, India  

NASA Astrophysics Data System (ADS)

Field stratigraphy and optical and radiocarbon dating of lateral moraines in the monsoon dominated Dunagiri valley of the Central Himalaya provide evidence for three major glaciations during the last 12 ka. The oldest and most extensive glaciation, the Bangni Glacial Stage-I (BGS-I), is dated between 12 and 9 ka, followed by the BGS-II glaciation (7.5 and 4.5 ka) and the BGS-III glaciation (?1 ka). In addition, discrete moraine mounds proximal to the present day glacier snout are attributed to the Little Ice Age (LIA). BGS-I started around the Younger Dryas (YD) cooling event and persisted till the early Holocene when the Indian Summer Monsoon (ISM) strengthened. The less extensive BGS-II glaciation, which occurred during the early to mid-Holocene, is ascribed to lower temperature and decreased precipitation. Further reduction in ice volume during BGS-III is attributed to a late Holocene warm and moist climate. Although the glaciers respond to a combination of temperature and precipitation changes, in the Dunagiri valley decreased temperature seems to be the major driver of glaciations during the Holocene.

Sati, Sarswati Prakash; Ali, Sheikh Nawaz; Rana, Naresh; Bhattacharya, Falguni; Bhushan, Ravi; Shukla, Anil Dutt; Sundriyal, Yaspal; Juyal, Navin

2014-09-01

370

Vivid valleys, pallid peaks? Hypsometric variations and ruralurban land change in the Central Peruvian Andes  

PubMed Central

What happens to the land cover within the hinterland's altitudinal belts while Central Andean cities are undergoing globalization and urban restructuring? What conclusions can be drawn about changes in human land use? By incorporating a regional altitudinal zonation model, direct field observations and GIS analyses of remotely sensed long term data, the present study examines these questions using the example of Huancayo Metropolitano an emerging Peruvian mountain city of 420,000 inhabitants, situated at 3260masl in the Mantaro Valley. The study's results indicate that rapid urban growth during the late 1980s and early 1990s was followed by the agricultural intensification and peri-urban condominization at the valley floor (quechua) since the beginning of Peru's neoliberal era. Moreover, regarding the adjoining steep slopes (suni) and subsequent grassland ecosystems (puna), the research output presents land cover change trajectories that clearly show an expansion of human land use, such as reforestation for wood production and range burning for livestock grazing, even at high altitudes despite ruralurban migration trends and contrary to several results of extra-Andean studies. Consequently, ruralurban planners and policy makers are challenged to focus on the manifold impacts of globalization on human land use at all altitudinal belts of the Andean city's hinterland: toward sustainable mountain development that bridges the social and physical gaps from the bottom up. PMID:23564987

Haller, Andreas

2012-01-01

371

A Central Role for Carbon-Overflow Pathways in the Modulation of Bacterial Cell Death  

PubMed Central

Similar to developmental programs in eukaryotes, the death of a subpopulation of cells is thought to benefit bacterial biofilm development. However mechanisms that mediate a tight control over cell death are not clearly understood at the population level. Here we reveal that CidR dependent pyruvate oxidase (CidC) and ?-acetolactate synthase/decarboxylase (AlsSD) overflow metabolic pathways, which are active during staphylococcal biofilm development, modulate cell death to achieve optimal biofilm biomass. Whereas acetate derived from CidC activity potentiates cell death in cells by a mechanism dependent on intracellular acidification and respiratory inhibition, AlsSD activity effectively counters CidC action by diverting carbon flux towards neutral rather than acidic byproducts and consuming intracellular protons in the process. Furthermore, the physiological features that accompany metabolic activation of cell death bears remarkable similarities to hallmarks of eukaryotic programmed cell death, including the generation of reactive oxygen species and DNA damage. Finally, we demonstrate that the metabolic modulation of cell death not only affects biofilm development but also biofilm-dependent disease outcomes. Given the ubiquity of such carbon overflow pathways in diverse bacterial species, we propose that the metabolic control of cell death may be a fundamental feature of prokaryotic development. PMID:24945831

Thomas, Vinai Chittezham; Sadykov, Marat R.; Chaudhari, Sujata S.; Jones, Joselyn; Endres, Jennifer L.; Widhelm, Todd J.; Ahn, Jong-Sam; Jawa, Randeep S.; Zimmerman, Matthew C.; Bayles, Kenneth W.

2014-01-01

372

Adapting to Climate Variability and Change: Experiences from Cereal-Based Farming in the Central Rift and Kobo Valleys, Ethiopia  

NASA Astrophysics Data System (ADS)

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regionsthe Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20-30 years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977-2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change.

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rtter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

373

Adapting to climate variability and change: experiences from cereal-based farming in the central rift and Kobo Valleys, Ethiopia.  

PubMed

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions-the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99% of the respondents at the CRV and 96% at the Kobo Valley perceived an increase in temperature and 94% at CRV and 91% at the Kobo Valley perceived a decrease in rainfall over the last 20-30years. Inter-annual and intraseasonal rainfall variability also has increased according to the farmers. The observed climate data (1977-2009) also showed an increasing trend in temperature and high inter-annual and intra-seasonal rainfall variability. In contrast to farmers' perceptions of a decrease in rainfall totals, observed rainfall data showed no statistically significant decline. The interaction among various bio-physical and socio-economic factors, changes in rainfall intensity and reduced water available to crops due to increased hot spells, may have influenced the perception of farmers with respect to rainfall trends. In recent decades, farmers in both the CRV and Kobo have changed farming practices to adapt to perceived climate change and variability, for example, through crop and variety choice, adjustment of cropping calendar, and in situ moisture conservation. These relatively low-cost changes in farm practices were within the limited adaptation capacity of farmers, which may be insufficient to deal with the impacts of future climate change. Anticipated climate change is expected to impose new risks outside the range of current experiences. To enable farmers to adapt to these impacts critical technological, institutional, and market-access constraints need to be removed. Inconsistencies between farmers' perceptions and observed climate trends (e.g., decrease in annual rainfall) could lead to sub-optimal or counterproductive adaptations, and therefore must be removed by better communication and capacity building, for example through Climate Field Schools. Enabling strategies, which are among others targeted at agricultural inputs, credit supply, market access, and strengthening of local knowledge and information services need to become integral part of government policies to assist farmers to adapt to the impacts of current and future climate change. PMID:23943096

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rtter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

374

Central Avra Valley Storage and Recovery Project (CAVSARP) Site, Tucson, Arizona: Floodwater and Soil Moisture Investigations with Extraterrestrial Applications  

NASA Technical Reports Server (NTRS)

Planetary geologists, geomorphologists, and hydrologists have hypothesized that Mars is a dynamic, water-enriched planet since the Mariner and Viking missions based on geologic, geomorphic, and topographic information. Recent acquisition of Gamma Ray and Neutron Spectrometer information has added further credence to this hypothesis. A unique investigation is underway to work towards being able to successfully map the extent and depth of water on Mars. Researchers from the University of Arizona and members of the Autonomous Sciencecraft Experiment (ASE) have been compiling multiple layers of information in time and space at the Central Avra Valley Storage and Recovery Project (CAVSARP) site, Tucson, Arizona, for eventual comparative analysis. This information has been acquired from a variety of observational/scientific platforms in controlled conditions. CAVSARP facility:

Rucker, D. F.; Dohm, J. M.; Ferre, T. P. A.; Ip, Felipe; Baker, V. R.; Davies, A. G.; Castano, R.; Chien, S.; Doggett, T. C.

2004-01-01

375

Swollen head syndrome associated with E. coli and infectious bronchitis virus in the Central Valley of California.  

PubMed

A commercial broiler flock in the Central Valley of California experienced a sudden increase in mortality due to heavy culling. Clinical signs included a snick, swollen heads and severe depression. Necropsy and histology revealed tracheitis, rhinitis, facial cellulitis, blepharitis, episcleritis, otitis media and caseous exudate within the air spaces of cranial bones. Escherichia coli serotype O78 was isolated from all lesions. Infectious bronchitis virus (Massachusetts serotype) was isolated from trachea/nasal cavity tissue pool. Adenovirus group 1 was isolated from trachea/nasal cavity and caecal tonsil tissue pools. Serum samples were positive for infectious bronchitis using ELISA and haemagglutination inhibition tests, but negative for turkey rhinotracheitis by an ELISA using the British antigen. This case suggests that swollen head syndrome can be associated with viruses other than pneumovirus. PMID:18671139

Droual, R; Woolcock, P R

1994-12-01

376

Depositional microfacies and burial diagenesis of Upper Jurassic Cotton Valley Limestone, Teague Townsite field, central Texas  

SciTech Connect

The Cotton Valley Limestone, like the older Smackover, was deposited on a ramp where the monotonous regional topography was punctuated by salt-generated and basement highs that greatly influenced local depositional environments. Teague Townsite field is located above a salt ridge that was once divided into several domes where Cotton Valley grainstones were deposited. Open marine wackestones and packstones surrounded those oolite shoals and, updip, shaly wackestones were deposited in a more restricted environment. An overall increase upward in the carbonate grain/mud ratio resulted from a Late Jurassic regional regression. Nine smaller, shoaling-upward cycles are present in the study area; they probably reflect local salt movements. The reservoir at Teague Townsite field is mainly intraparticle porosity formed by early leaching of metastable allochems in the meteoric phreatic environment that was contemporaneous with several of the periods of local emergence. Neomorphism and replacement were common in early diagenesis. Subsequently, compaction, stylolitization, sparite cementation, and introduction of saddle dolomite occurred. Whole-rock analyses indicate that the present-day trace element distribution reflects (1) early cementation and flushing of porous zones; (2) comparatively less flushing of muddy zones; and (3) introduction of subsurface fluids. Whole-rock deltaO/sup 18//deltaC/sup 13/ values plot within the range of published data for typical Jurassic cements. A tendency toward heavier isotopic composition with increasing depth is interpreted to be the result of subsurface fluid influx during burial diagenesis.

Ahr, W.M.; Faucette, R.C.; Steffensen, C.

1983-03-01

377

Recognition of Paleoseismicity along Creeping Faults: Examples from the Dry Lake Valley Site on the central San Andreas  

NASA Astrophysics Data System (ADS)

Fault segmentation and probabilistic seismic hazard models rely heavily on data from paleoseismic investigations, however, relatively little paleoseismic data emanate from actively creeping faults such as the central San Andreas Fault (SAF). Geodetic studies have shown that this part of the SAF has been creeping at nearly 30 mm/yr during the historical period. Yet, only a handful of paleoseismic studies have been conducted. None of these have revealed unequivocal evidence of fault rupture. However, this does not mean that this portion of the SAF has not generated large earthquakes over the timespan breached by paleoseismology. Many pieces of data, such as displaced stratigraphy, unconformities, and folds, that would be utilized as evidence for a paleoearthquake on faults that are not historically creeping have been found in these trenches. These observations cannot be interpreted as earthquakes in light of historical aseismic creep. Generally, when facing fault creep, the best evidence for paleoearthquakes are observations of large ground failures such as filled fissures and buried fault scarp-derived colluvial wedges. At the 2012 Dry Lake Valley paleoseismic site, along the central creeping section of the SAF (DLV site; 36.46791, -121.05564), we exposed a sub-vertical, matrix-supported, package of large clasts (pebbles to boulders) within the main fault zone. Despite the apparent fissure shape and a capping horizon, discussions with independent trench reviewers led to several models for emplacing the gravel package within the fault zone at this orientation and without large earthquakes. Fault-parallel trenching revealed a source for the large clasts nearby the original excavation, however interpretation of a paleoearthquake remains ambiguous. Here, we present conceptual models and observations from the Dry Lake Valley paleoseismic site depicting how creep can create structures that are similar to paleoearthquakes and how creep may overprint paleoearthquake evidence, making it ambiguous. Finally, we present strategies for recognizing paleoseismicity in the face of creep.

Toke, N.; Abueg, N.; Anderson, J.; Kellum, L.; Selck, J.; Sato, T.; Salisbury, J. B.; Arrowsmith, R.

2012-12-01

378

SESSION B: CENTRAL VALLEY RIPARIAN HABITATS To the majority of people who responded to the first expressions of concern over the  

E-print Network

SESSION B: CENTRAL VALLEY RIPARIAN HABITATS To the majority of people who responded to the first expressions of concern over the catastrophic loss of riparian habitats in California, the focus was entirely in need of preservation. At the 1981 Riparian Systems Conference, a number of excellent papers described

Standiford, Richard B.

379

Dhaba: An initial report on an Acheulean, Middle Palaeolithic and microlithic locality in the Middle Son Valley, north-central India  

Microsoft Academic Search

This paper presents the first report on Dhaba, a newly discovered locality in the Middle Son Valley, north-central India. The locality preserves Acheulean, Middle Palaeolithic and microlithic artefacts within a Late Quaternary stratified alluvial sequence. Initial information is provided on the sedimentary sequence, archaeological survey and excavation, topographical mapping, and lithic technological analysis of Dhaba 1, the largest excavation at

Michael Haslam; Clair Harris; Chris Clarkson; J. N. Pal; Ceri Shipton; Alison Crowther; Jinu Koshy; Janardhana Bora; Peter Ditchfield; Harindra Prasad Ram; Kathryn Price; A. K. Dubey; Michael Petraglia

380

A comparative study of scattering, intrinsic, and coda Q exp -1 for Hawaii, Long Valley, and central California between 1.5 and 15.0 Hz  

Microsoft Academic Search

The effects of scattering Q exp -1 and intrinsic Q exp -1 were separated from an analysis of the S wave and its coda in Hawaii, Long Valley, and central California by means of a novel method developed by Hoshiba et al. (1991). This method is based on the integration of the S-wave energy for three successive time windows as

Kevin Mayeda; Stuart Koyanagi; Mitsuyuki Hoshiba; Keiiti Aki; Yuehua Zeng

1992-01-01

381

Alkaline Basalts of The Quaternary Buffalo Valley Volcanic Field, NW Fish Creek Mountains, North-central Nevada, Great Basin  

NASA Astrophysics Data System (ADS)

The Buffalo Valley volcanic field, 5 km southwest of Battle Mountain, consists of approximately 11 cinder cones and associated flows. Youthful volcanoes are rare in the region, and thus this field offers the opportunity to investigate mantle sources currently beneath the central Great Basin. Most of the eruptive centers are distributed along the northwestern margin of the Fish Creek Mountains, a mid-Tertiary caldera complex, along a 13-km-long northeasterly trend that is perpendicular to the regional stress field (or GPS velocity field), suggesting fault control or eruption from a now-buried fissure. The cones are geomorphologically youthful, with well-defined, commonly breached craters. At least one cone, situated slightly east of the main trend, consists of only a thin mantle of scoria and bombs overlying grey Paleozoic limestone. Previous K-Ar and Ar-Ar dating indicate that the cones are between 1.29 and 0.95 Ma in age. Two other nearby Quaternary volcanic centers lie northeast of the Fish Creek Mountains (K-Ar date of 3.3 Ma) and in the center of the Fish Creek caldera (age unknown). Rare Tertiary basalts and more common Tertiary andesites lie around the margin of the caldera. Lavas from the Buffalo Valley cones have vesicular flow tops and more massive interiors. All Quaternary centers are similar petrographically, including 1-2% olivine phenocrysts and megacrysts up to 1 cm in size, and characteristic plagioclase megacrysts that are rarely up to 4 cm long, commonly in a glassy matrix. Two cone samples are alkalic basalt and tephrite with Mg numbers of 0.55, high TiO2 (2.4%), K2O (2.0%), light REE, Nb (60 ppm), but low Cr and Ni (80 ppm), Pb (2 ppm), Ba (450 ppm) and 87Sr/86Sr (0.70375) compared to Late Pliocene/Quaternary volcanic rocks from the western Great Basin near Reno/Carson City/Fallon. The Buffalo Valley cones are similar chemically to lavas from the Pliocene-Quaternary Lunar Craters volcanic field in central Nevada, and are melts of mantle that is enriched in incompatible elements compared to MORB source mantles. This source is distinct from that currently beneath the western Great Basin where mantle sources include a significant subduction component.

Cousens, B.; Henry, C. D.

2008-12-01

382

California: San Joaquin Valley  

Atmospheric Science Data Center

article title: Fog and Haze in California's San Joaquin Valley ... Imaging SpectroRadiometer (MISR) images of southern California and southwestern Nevada acquired on January 3, 2001 (Terra orbit ... San Joaquin Valley, which comprises the southern extent of California's Central Valley, covers much of the viewed area. Also visible are ...

2014-05-15

383

Dabbling duck harvest dynamics in the Central Valley of California--implications for recruitment  

USGS Publications Warehouse

Age and sex ratios and body weights were obtained for northern pintails (Anas acuta), mallards (A. platyrhynchos), American wigeon (A. americana), green-winged teal (A. crecca), and northern shovelers (A. clypeata) shot at Mendota State Wildlife Area in the San Joaquin Valley (SANJV) and at Sacramento National Wildlife Refuge in the Sacramento Valley (SACV) during 1982-83 and 1983-84. Age ratios were determined for pintails at four locations during 1980-83. Cooperative Waterfowl Parts Collection Survey (1982-84; U.S. Fish and Wildlife Service) and California preseason-banding data (1973-77, for mallards and pintails) also were used to measure age ratios of the California harvest. Harvest rate (ducks shot per day) was obtained and summed from all SACV and SANJV public hunting areas in 1982-84. All species except female wigeon and adult female mallards lost weight between October and January. Except for wigeon, harvest rate was high in October when hunting began. Harvest rates were low in November and December but rose markedly in January in the SACV for all species and for all except pintails in the SANJV. Proportion of adults in the bag as measured by all methods increased progressively through the hunting season. Proportion of adults in the harvest was higher in 1982-83 than in 1983-84 and was greater in the SACV than the SANJV both years for most species. Adult females formed a small component of total kill but 50% or more of female kill. The harvest of pintails at a SACV and a SANJV location consistently contained about half as many immatures per adult as that at two other California locations for 1980-83. The substantial harvest of adults in January eliminates the most productive breeders from the population. Thus, winter hunting mortality may influence age composition of the spring flight and, hence, recruitment potential of the breeding population.

Miller, M.R.; Beam, J.; Connelly, D.P.

1988-01-01

384

Chronology and climatic implications of Late Quaternary glaciations in the Goriganga valley, central Himalaya, India  

NASA Astrophysics Data System (ADS)

Goriganga valley, which is located in the transition zone between the dry steppe of the Tibetan plateau in the north and the sub-humid Himalayan climate in the south, has preserved four events of glaciation with decreasing magnitude. The oldest Stage-I glaciation is represented by a 12.5 km long discontinuous diamictite ridge which terminates north of Rilkot (3100 m asl). The Stage-II glaciation is represented by sub-rounded and partially eroded lateral moraines and terminates around Martoli village (3240 m asl). The Stage-III and IV glacial moraines are sharp crested, unstable and terminate proximal to the present day glacier at