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1

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

2

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

3

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

4

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

Federal Register 2010, 2011, 2012, 2013

...Plan/Environmental Impact Statement, Death Valley National Park, Inyo County, CA...Saline Valley Warm Springs Management Plan, Death Valley National Park...Valley Warm Springs Management Plan for Death Valley [[Page 33238

2012-06-05

5

Central Valley Water Resource Study.  

National Technical Information Service (NTIS)

There is growing concern over water quality in the Central Valley of California, particularly in the Sacramento-San Joaquin Delta. Federal actions on both water quality standards and water project development are of major significance in future water mana...

1970-01-01

6

Trinity Division: Central Valley Project.  

National Technical Information Service (NTIS)

The Central Valley Project (CVP) continued expanding in California after completion of the Project's initial features. The Trinity River Division was part of this expansion. California picked up on the idea for the Division from a Federal Power Commission...

E. A. Stene

1996-01-01

7

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.

8

The Central Valley Hydrologic Model  

NASA Astrophysics Data System (ADS)

Historically, California’s Central Valley has been one of the most productive agricultural regions in the world. The Central Valley also is rapidly becoming an important area for California’s expanding urban population. In response to this competition for water, a number of water-related issues have gained prominence: conjunctive use, artificial recharge, hydrologic implications of land-use change, subsidence, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS made a detailed assessment of the Central Valley aquifer system that includes the present status of water resources and how these resources have changed over time. The principal product of this assessment is a tool, referred to as the Central Valley Hydrologic Model (CVHM), that simulates surface-water flows, groundwater flows, and land subsidence in response to stresses from human uses and from climate variability throughout the entire Central Valley. The CVHM utilizes MODFLOW combined with a new tool called “Farm Process” to simulate groundwater and surface-water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis. This model was discretized horizontally into 20,000 1-mi2 cells and vertically into 10 layers ranging in thickness from 50 feet at the land surface to 750 feet at depth. A texture model constructed by using data from more than 8,500 drillers’ logs was used to estimate hydraulic properties. Unmetered pumpage and surface-water deliveries for 21 water-balance regions were simulated with the Farm Process. Model results indicate that human activities, predominately surface-water deliveries and groundwater pumping for irrigated agriculture, have dramatically influenced the hydrology of the Central Valley. These human activities have increased flow though the aquifer system by about a factor of six compared to pre-development conditions. The simulated hydrology reflects spatial and temporal variability in climate, land-use changes, and available surface-water deliveries. For example, the droughts of 1976-77 and 1987-92 led to reduced streamflow and surface-water deliveries and increased evapotranspiration and groundwater pumpage throughout most of the valley, resulting in a decrease in groundwater storage. Since the mid-1990s, annual surface-water deliveries generally have exceeded groundwater pumpage, resulting in an increase or no change in groundwater storage throughout most of the valley. However, groundwater is still being removed from storage during most years in the southern part of the Central Valley. The CVHM is designed to be coupled with Global Climate Models to forecast the potential supply of surface-water deliveries, demand for groundwater pumpage, potential subsidence, and changes in groundwater storage in response to different climate-change scenarios. The detailed database on texture properties coupled with CVHM's ability to simulate the combined effects of recharge and discharge make CVHM particularly useful for assessing water-management plans, such as conjunctive water use, conservation of agriculture land, and land-use change. In the future, the CVHM could be used in conjunction with optimization models to help evaluate water-management alternatives to effectively utilize the available water resources.

Faunt, C.; Belitz, K.; Hanson, R. T.

2009-12-01

9

Excavations at Harmony Borax Works: Historical Archeology at Death Valley National Monument.  

National Technical Information Service (NTIS)

The report gives details of excavations at Harmony Borax Works, Death Valley National Monument, California. Harmony was the central feature in the opening of Death Valley. During the 1880s, 20-mule teams hauled borax from Harmony to the rail head at Mojav...

G. A. Teague L. O. Shenk

1977-01-01

10

36 CFR 7.26 - Death Valley National Monument.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Death Valley National Monument. 7.26 Section...OF THE NATIONAL PARK SYSTEM § 7.26 Death Valley National Monument. (a) Mining. Mining in Death Valley National Monument is subject...

2013-07-01

11

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.

12

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

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

Life in Death Valley: The Mystery of the Racing Rocks  

NSDL National Science Digital Library

This PBS site provides information of the mysterious sliding rocks in Death Valley, reviews competing hypotheses, and features the work of a geologist using GPS in her investigation. The site includes a photo of a rock and its track.

2010-06-29

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

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...

17

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

18

Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California  

Microsoft Academic Search

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

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

2009-01-01

19

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

20

Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California  

NASA Astrophysics Data System (ADS)

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 ?m diameter cocci, <2.5 ?m 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.

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

2009-06-01

21

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

22

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

23

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

24

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

25

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

26

Inventory of amphibians and reptiles at Death Valley National Park  

USGS Publications Warehouse

As part of the National Park Service Inventory and Monitoring Program in the Mojave Network, we conducted an inventory of amphibians and reptiles at Death Valley National Park in 2002-04. Objectives for this inventory were to: 1) Inventory and document the occurrence of reptile and amphibian species occurring at DEVA, primarily within priority sampling areas, with the goal of documenting at least 90% of the species present; 2) document (through collection or museum specimen and literature review) one voucher specimen for each species identified; 3) provide a GIS-referenced list of sensitive species that are federally or state listed, rare, or worthy of special consideration that occur within priority sampling locations; 4) describe park-wide distribution of federally- or state-listed, rare, or special concern species; 5) enter all species data into the National Park Service NPSpecies database; and 6) provide all deliverables as outlined in the Mojave Network Biological Inventory Study Plan. Methods included daytime and nighttime visual encounter surveys, road driving, and pitfall trapping. Survey effort was concentrated in predetermined priority sampling areas, as well as in areas with a high potential for detecting undocumented species. We recorded 37 species during our surveys, including two species new to the park. During literature review and museum specimen database searches, we recorded three additional species from DEVA, elevating the documented species list to 40 (four amphibians and 36 reptiles). Based on our surveys, as well as literature and museum specimen review, we estimate an overall inventory completeness of 92% for Death Valley and an inventory completeness of 73% for amphibians and 95% for reptiles. Key Words: Amphibians, reptiles, Death Valley National Park, Inyo County, San Bernardino County, Esmeralda County, Nye County, California, Nevada, Mojave Desert, Great Basin Desert, inventory, NPSpecies.

Persons, Trevor B.; Nowak, Erika M.

2006-01-01

27

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

28

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

29

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...

30

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.

31

Eagle Borax Works, Harmony Borax Works, Death Valley National Monument, California.  

National Technical Information Service (NTIS)

In this report the author suggests that in his view the most significant historical activity that occurred in Death Valley was the mining and processing of Borax. The purpose of this report has been to study the history of Death Valley National Monument. ...

F. R. Holland R. V. Simmonds

1971-01-01

32

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

33

Tehama-Colusa, Central Valley Project, California.  

National Technical Information Service (NTIS)

The report describes the proposal for construction of a 122-mile Tehama-Colusa Canal, Tehama, Colusa and Glenn Counties, California on west side of Sacramento Valley to serve approximately 244,500 irrigable acres in the Tehama-Colusa service area. Include...

1972-01-01

34

Late Cenozoic tephrochronology, stratigraphy, geomorphology, and neotectonics of the Western Black Mountains Piedmont, Death Valley, California: Implications for the spatial and temporal evolution of the Death Valley fault zone  

Microsoft Academic Search

This study presents the first detailed tephrochronologic study of the central Death Valley area by correlation of a Nomlaki-like tuff (>3.35 Ma), tuffs of the Mesquite Spring family (3.1 -- 3.35 Ma), a tuff of the lower Glass Mountain family (1.86 -- 2.06 Ma), and tephra layers from the upper Glass Mountain family (0.8 -- 1.2 Ma), the Bishop ash

Jeffrey Rayburn Knott

1998-01-01

35

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

36

Gravity survey of Dixie Valley, west-central Nevada  

USGS Publications Warehouse

Dixie Valley, a northeast-trending structural trough typical of valleys in the Basin and Range Province, is filled with a maximum of about 10,000 feet of alluvial and lacustrine deposits , as estimated from residual-gravity measurements obtained in this study. On the basis of gravity measurements at 300 stations on nine east-west profiles, the gravity residuals reach a maximum of 30 milligals near the south-central part of the valley. Results from a three-dimensional inversion model indicate that the central depression of the valley is offset to the west of the geographic axis. This offset is probably due to major faulting along the west side of the valley adjacent to the Stillwater Range. Comparison of depths to bedrock obtained during this study and depths obtained from a previous seismic-refraction study indicates a reasonably good correlation. A heterogeneous distribution of densities within the valley-fill deposits would account for differing depths determined by the two methods. (USGS)

Schaefer, Donald H.

1983-01-01

37

Gravity survey of Dixie Valley, west-central Nevada  

SciTech Connect

Dixie Valley, a northeast-trending structural trough typical of valleys in the Basin and Range Province, is filled with a maximum of about 10,000 feet of alluvial and lacustrine deposits, as estimated from residual-gravity measurements obtained in this study. On the basis of gravity measurements at 300 stations on nine east-west profiles, the gravity residuals reach a maximum of 30 milliGals near the south-central part of the valley. Results from a three-dimensional inversion model indicate that the central depression of the valley is offset to the west of the geographic axis. This offset is probably due to major faulting along the west side of the valley adjacent to the Stillwater Range. Comparison of depths to bedrock obtained during this study and depths obtained from a previous seismic-refraction study indicates a reasonably good correlation. A heterogeneous distribution of densities within the valley-fill deposits would account for differing depths determined by the two methods. 17 refs., 4 figs., 2 tabs.

Schaefer, D.H.

1983-01-01

38

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

39

Terpenes emitted from agricultural species found in California's Central Valley  

NASA Astrophysics Data System (ADS)

More than a dozen monoterpenes have been identified as emissions from agricultural and natural plant species occupying large acreages in the Central Valley of California, including as dominant emissions camphene, 2-carene, ?3-carene, limonene, myrcene, trans-ocimene, ?-phellandrene, ?-pinene, ?-pinene, sabinene, ?-terpinene, and terpinolene. Isoprene was not a significant emission from any of the crop species examined but was emitted by a Valley Oak. In addition to the monoterpenes, sesquiterpenes were emitted from approximately one third of the species investigated, in some cases at higher levels than the monoterpene emissions from the same plant. The possible contributions of these biogenic emissions to the ozone exceedances in the Central Valley should be considered in planning future emission control strategies.

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

1991-05-01

40

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

41

Central Valley Project proposed power rate increase environmental assessment  

SciTech Connect

The proposed action is to: (1) increase the Central Valley Project (CVP) wholesale rates from a current composite rate of around 10 mills/kWh to around 40 mills/kWh by October 1986; (2) establish new rates for firm and nonfirm wheeling service; and (3) establish provisions for an interruptible power service. Environmental, social and economic impacts are discussed.

Not Available

1983-01-01

42

Central Valley California: High Intensity Drug Trafficking Area. Drug Market Analysis, 2011.  

National Technical Information Service (NTIS)

This is the Central Valley California High Intensity Drug Trafficking Area (HIDTA) Drug Market Analysis for 2011. The overall drug threat to the Central Valley California HIDTA region has remained fairly consistent over the past year. Mexican drug traffic...

2011-01-01

43

Ground Water in the Central Valley, California: A Summary Report. Regional Aquifer-System Analysis, Central Valley, California.  

National Technical Information Service (NTIS)

The agricultural productivity of the Central Valley depends on irrigation. Half of the 22 million acre-feet of irrigation water applied annually is ground water. Nearly all the fresh ground water is contained in the continental rocks and deposits younger ...

G. L. Bertoldi R. H. Johnston K. D. Evenson

1991-01-01

44

The Black Mountains turtlebacks: Rosetta stones of Death Valley tectonics  

NASA Astrophysics Data System (ADS)

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 structural evolution of Death Valley, and because of the outstanding rock exposure, they also provide valuable natural laboratories for observing structural processes. There are three turtlebacks: the Badwater turtleback in the north, the Copper Canyon turtleback, and the Mormon Point turtleback in the south. Although important differences exist among them, each turtleback displays a doubly plunging antiformal core of metamorphic and igneous rock and a brittle fault contact to the northwest that is structurally overlain by Miocene-Pleistocene volcanic and/or sedimentary rock. The turtleback cores contain mylonitic rocks that record an early period of top-southeastward directed shear followed by top-northwestward directed shear. The earlier formed mylonites are cut by, and locally appear concurrent with, 55-61 Ma pegmatite. We interpret these fabrics as related to large-scale, basement-involved thrust faults at the turtlebacks, now preserved as areally-extensive, metamorphosed, basement over younger-cover contacts. The younger, and far more pervasive, mylonites record late Tertiary extensional unroofing of the turtleback footwalls from mid-crustal depths. Available geochronology suggests that they cooled through 300 °C at different times: 13 Ma at Badwater; 6 Ma at Copper Canyon; 8 Ma at Mormon Point. At Mormon Point and Copper Canyon turtlebacks these dates record cooling of the metamorphic assemblages from beneath the floor of an ˜ 11 Ma Tertiary plutonic complex. Collectively these relationships suggest that the turtlebacks record initiation of ductile extension before ˜ 14 Ma followed by injection of a large plutonic complex along the ductile shear zone. Ductile deformation continued during extensional uplift until the rocks cooled below temperatures for crystal plastic deformation by 6-8 Ma. Subsequent low-angle brittle fault slip led to final exposure of the igneous and metamorphic complex. The turtleback shear zones can constrain models for crustal extension from map-view as well as cross-sectional perspectives. In map view, the presence of basement-involved thrust faults in the turtlebacks suggest the Black Mountains were a basement high prior to late Tertiary extension. In cross-section, the turtleback geometries and histories are most compatible with models that call on multiple faults rather than a single detachment to drive post-11 Ma extension.

Miller, Marli B.; Pavlis, Terry L.

2005-12-01

45

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 basins—Furnace Creek, Amargosa Valley, Opera House, and central Death Valley—in California and Nevada. It extends over three full 7.5-minute quadrangles, and parts of eleven others—an 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

46

Influence of rock strength on the valley morphometry of Big Creek, central Idaho, USA  

Microsoft Academic Search

Analysis of valley morphometry and bedrock strength along Big Creek, central Idaho, shows that valley floor width is strongly controlled by bedrock. We performed statistical analysis of Schmidt hammer rock strength as a function of lithology and aspect and of valley morphometry as a function of rock strength. Rock strength is significantly greater on the south side of the valley

Zachery M. Lifton; Glenn D. Thackray; Robert Van Kirk; Nancy F. Glenn

2009-01-01

47

Winter habitat associations of diurnal raptors in Californias Central Valley  

USGS Publications Warehouse

The wintering raptors of California's Central Valley are abundant and diverse. Despite this, little information exists on the habitats used by these birds in winter. We recorded diurnal raptors along 19 roadside survey routes throughout the Central Valley for three consecutive winters between 2007 and 2010. We obtained data sufficient to determine significant positive and negative habitat associations for the White-tailed Kite (Elanus leucurus), Bald Eagle {Haliaeetus leucocephalus), Northern Harrier (Circus cyaneus), Red-tailed Hawk (Buteo jamaicensis), Ferruginous Hawk (Buteo regalis), Rough-legged Hawk (Buteo lagopus), American Kestrel (Falco sparverius), and Prairie Falcon (Falco mexicanus). The Prairie Falcon and Ferruginous and Rough-legged hawks showed expected strong positive associations with grasslands. The Bald Eagle and Northern Harrier were positively associated not only with wetlands but also with rice. The strongest positive association for the White-tailed Kite was with wetlands. The Red-tailed Hawk was positively associated with a variety of habitat types but most strongly with wetlands and rice. The American Kestrel, Northern Harrier, and White-tailed Kite were positively associated with alfalfa. Nearly all species were negatively associated with urbanized landscapes, orchards, and other intensive forms of agriculture. The White-tailed Kite, Northern Harrier, Redtailed Hawk, Ferruginous Hawk, and American Kestrel showed significant negative associations with oak savanna. Given the rapid conversion of the Central Valley to urban and intensive agricultural uses over the past few decades, these results have important implications for conservation of these wintering raptors in this region.

Pandolrno, E. R.; Herzog, M. P.; Hooper, S. L.; Smith, Z.

2011-01-01

48

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

49

Role of seismogenic processes in fault-rock development: An example from Death Valley, California  

NASA Astrophysics Data System (ADS)

Fault rocks developed along the Mormon Point turtleback of southern Death Valley suggest that a jog in the oblique-slip Death Valley fault zone served as an ancient seismic barrier, where dominantly strike-slip ruptures were terminated at a dilatant jog. Dramatic spatial variations in fault-rock thickness and type within the bend are interpreted as the products of: (1) fault "overshoot," in which planar ruptures bypass the intersection of the two faults composing the bend and slice into the underlying footwall; and (2) implosion brecciation, in which coseismic ruptures arrested at a releasing bend in the fault lead to catastrophic collapse brecciation, fluid influx, and mineralization.

Pavlis, Terry L.; Serpa, Laura F.; Keener, Charles

1993-03-01

50

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

51

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

52

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

53

Sliding rocks at the Racetrack, Death Valley: What makes them move?  

Microsoft Academic Search

Sharply angular boulders as large as 320 kg sit on the Racetrack Playa, Death Valley, California; trails leading to them indicate that the rocks have moved large distances. The process has never been witnessed. Although high winds and a wetted surface seem necessary, controversy persists about the need for other conditions, especially ice sheets. On the basis of experiments with

John B. Reid Jr.; Edward P. Bucklin; Lily Copenagle; Jon Kidder; Sean M. Pack; Pratigya J. Polissar; Michael L. Williams

1995-01-01

54

The depositional environments and petrography of the Stirling Quartzite Death Valley Region, California and Nevada  

Microsoft Academic Search

The Stirling Quartzite is a relatively unmetamorphosed, predominantly clastic formation of latest Precambrian age which accumulated during the early stages of a Cordilleran miogeocline. It is extensively exposed throughout the Death Valley region of California and Nevada. The formation was divided into fine members A-E. The stratigraphic arrangement of the members is such that the lower and upper halves of

W. E. Wertz

1983-01-01

55

Mineral biosignatures in evaporites: Presence of rosickyite in an endoevaporitic microbial community from Death Valley, California  

Microsoft Academic Search

Rosickyite is a rare form of sulfur (gamma-sulfur; monoclinic symmetry) that is not thermodynamically predicted to be stable at Earth's surface temperatures; instead, it reverts to the more common alpha-sulfur form (orthorhombic symmetry). Here we show, for the first time, that rosickyite exists and is stably maintained within an endoevaporitic microbial community from the salt pan of Death Valley, California.

Susanne Douglas; Heixong Yang

2002-01-01

56

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

57

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.

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

2009-01-01

58

The evaluation of water storage in Death Valley using GRACE satellite data  

NASA Astrophysics Data System (ADS)

As drought conditions spread across the United States, concerns over water supplies, water use, and water management policies are growing and possible contributing environmental factors are continually being scrutinized. This thesis examines Death Valley as an analog for Southern Nevada and utilizes NASA EOS data, combined with ancillary climate data, to assess the effect of decadal climate variability on groundwater storage in the Death Valley area. Historical climate data, combined with satellite imagery observations, were compiled and calculated for analyses. Conclusions derived from statistical analyses infer trends between GRACE (Gravity Recovery and Climate Experiment) satellite data and fluctuating levels of recharge and groundwater storage, as well as climatic changes in temperature and rainfall. The observations show seasonal variations in ground water thickness of up to 10 cm from the mean, correlated directly to seasonal temperature variability. Connections were also observed between temperature and precipitation with a correlation factor of -0.5. The relationship between precipitation and groundwater thickness change is also evident, with a correlation factor of 0.4 where evaporation and delayed aquifer response are likely impacting direct correlation. The research illustrates how and which environmental factors are impacting the groundwater storage in Death Valley. Due to the similarity of climates between Death Valley and Southern Nevada, this research may be used as an analogy illustrating the impact of climate variability in Southern Nevada. The research, combining GRACE satellite observations and downscaled historical climate data will show any adverse effects that climate variability may be having on the area, including the impact it has on aquifers, and the impact it has on Death Valley's water supply in general.

Sweigart, Maile J.

59

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

60

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

Microsoft Academic Search

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

K. W. Katzenstein; J. W. Bell

2005-01-01

61

A new hypothesis for the amount and distribution of dextral displacement along the Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, California-Nevada  

NASA Astrophysics Data System (ADS)

The Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, a ~250 km long, predominantly right-lateral structure in California and Nevada, is a key element in tectonic reconstructions of the Death Valley area, Eastern California Shear Zone and Walker Lane, and central Basin and Range Province. Total displacement on the fault zone is contested, however, with estimates ranging from ~30 to ~63 km or more. Here we present a new synthesis of available constraints. Preextensional thrust faults, folds, and igneous rocks indicate that offset reaches a maximum of ~50 km. Neogene rocks constrain its partitioning over time. Most offset is interpreted as ? ~13-10 Ma, accruing at ~3-5 mm/yr in the middle of the fault zone and more slowly toward the tips. The offset markers imply ~68 ± 14 km of translation between the Cottonwood Mountains and Resting Spring-Nopah Range (~60 ± 14 km since ~15 Ma) through a combination of strike slip and crustal extension. This suggests that a previous interpretation of ~104 ± 7 km, based on the middle Miocene Eagle Mountain Formation, is an overestimate by ~50%. Our results also help to mitigate a discrepancy in the ~12-0 Ma strain budget for the Eastern California Shear Zone. Displacement has previously been estimated at ~100 ± 10 km and ~67 ± 6 km for the Basin and Range and Mojave portions of the shear zone, respectively. Our new estimate of ~74 ± 17 km for the Basin and Range is within the uncertainty of the Mojave estimate.

Renik, Byrdie; Christie-Blick, Nicholas

2013-03-01

62

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

Microsoft Academic Search

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

J. S. Noller; M. C. Reheis

1993-01-01

63

An Impact Crater in Palm Valley, Central Australia?  

NASA Astrophysics Data System (ADS)

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.; Buchel, Andrew; O'Neill, Craig; Britton, Tui R.

2011-05-01

64

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

65

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

66

The Next Step in Central Valley Flood Management: Connecting Costs and Benefits  

Microsoft Academic Search

Historically, large expanses of California's low-lying Central Valley flooded nearly every winter. Over the past 150 years, individuals, communities, and state and national agencies have increasingly altered the landscape with levees, reservoirs, and bypasses to support agriculture and urban centers. The Central Valley's flood protection infrastructure and the institutions that manage flood risks have coevolved as risks and local needs

Kaveh Madani; Dana Rowan; Jay Lund

67

Homogenization of Fall-Run Chinook Salmon Gene Pools in the Central Valley of California, USA  

Microsoft Academic Search

We assessed the population genetic structure and temporal stability of genetic diversity from 1999 to 2001 in collections of fall-run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley. Tests for genotypic differentiation at seven microsatellite loci revealed few significant pairwise comparisons between samples from five hatchery populations and eight naturally spawning populations throughout the Central Valley that were separated by

Kevin S. Williamson; Bernie May

2005-01-01

68

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

Microsoft Academic Search

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

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

2002-01-01

69

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

70

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

SciTech Connect

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 that occurred on a 100 k.y. time scale. These cycles begin with mud-flat deposits (192 ka to bottom of core, and 60 ka to 120 ka). Wetter and/or colder conditions produced greater effective moisture; saline pan and shallow saline lake evaporites overlie mud-flat sediments (186 ka to 192 ka and 35 ka to 60 ks). Eventually, enough water entered Death Valley to sustain perennial lakes that had fluctuating water levels and salinities (120 ka to 186 ka and 10 ka to 35 ka). When more arid conditions returned, mud-flat deposits accumulated on top of the perennial lake sediments, completing the cycle (120 ka and 10 ka). Of particular significance are the major lacustrine phases, 10 ka to 35 ka and 120 ka to 186 ka (oxygen isotope stages 2 and 5e--6), which represent markedly colder and wetter conditions than those of modern Death Valley. Of the two major lake periods, the penultimate glacial lakes were deeper and far longer lasting than those of the last glacial.

Lowenstein, T.K.; Li, J.; Brown, C. [State Univ. of New York, Binghamton, NY (United States). Dept. of Geological Sciences and Environmental Studies] [State Univ. of New York, Binghamton, NY (United States). Dept. of Geological Sciences and Environmental Studies; Roberts, S.M. [Western Montana Coll., Dillon, MT (United States). Environmental Sciences Dept.] [Western Montana Coll., Dillon, MT (United States). Environmental Sciences Dept.; Ku, T.L.; Luo, S. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Earth Sciences] [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Earth Sciences; Yang, W. [State Univ. of New York, Stony Brook, NY (United States). Marine Science Research Center] [State Univ. of New York, Stony Brook, NY (United States). Marine Science Research Center

1999-01-01

71

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

72

gastropods of the Death Valley-lower Colorado River region: relicts of a late Neogene marine incursion?  

Microsoft Academic Search

Aim A small fauna of amphibious snails (genus Assiminea Fleming, 1828) living in association with highly mineralized springs in the Death Valley-lower Colorado River region (DVLCR) is thought to be a relict of the Bouse Embayment, a putative late Miocene-early Pliocene transgression of the ancestral Gulf of California along the lower Colorado River valley. We analysed the phylogenetic relationships of

Robert Hershler; Hsiu-Ping Liu

73

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

Microsoft Academic Search

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

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

2001-01-01

74

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

NASA Astrophysics Data System (ADS)

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 the geophysical data, one active segment appears to offset the low-angle faults in the subsurface of Death Valley.

Keener, Charles; Serpa, Laura; Pavlis, Terry L.

1993-04-01

75

Hydrogeology of Palm Valley, central Australia; a Pleistocene flora refuge?  

NASA Astrophysics Data System (ADS)

The Palm Valley Oasis (Finke Gorge National Park) in arid central Australia is characterised by large stands of red cabbage palm trees ( Livistona mariae). How these unique plants, over 1000 km away from nearest relatives in the tropical parts of northern Australia persist, has long fascinated visitors. The hydrogeology of this area helps explain this phenomenon. Stable isotope (? 2H, ? 8O) analyses shows groundwater to have a uniform composition that plots on or near a local meteoric water line. Carbon-14 results are observed to vary throughout this aquifer from effectively dead (<4%) to 87% modern carbon. Ratios of chlorine-36 to chloride range from 130 to 290×10 -1536Cl/Cl. In this region atmospheric 36Cl/Cl ratio is around 300×10 -15. Thus an age range of around 300 ka is indicated if, as is apparent radioactive decay is the only significant cause of 36Cl/Cl variation within the aquifer. The classic homogenous aquifer with varying surface topography flow model is the simplest conceptual model that need be invoked to explain these data. Complexities, associated with local topography flow cells superimposed on the regional gradient, may mean groundwater with markedly different flow path lengths has been sampled. This potential flow path complexity, which is also evidenced by slight variation in groundwater cation ratios, can account for the distribution of isotope age data throughout the aquifer. Given the likely very slow travel times indicated by this aquifer's hydraulic properties, age differences of the magnitude indicated from chlorine-36 data are feasible. The likely slow travel times (>100 ka) along some flow paths indicate groundwater discharge would endure through arid phases associated with Quaternary climate oscillations. Such a flow system can explain the persistence of this population of Palms and also highlight the possibility that Palm Valley has acted as a flora refuge since at least the mid Pleistocene.

Wischusen, John D. H.; Fifield, L. Keith; Cresswell, Richard G.

2004-06-01

76

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

77

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

78

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

79

Late Cenozoic tephrochronology, stratigraphy, geomorphology, and neotectonics of the Western Black Mountains Piedmont, Death Valley, California: Implications for the spatial and temporal evolution of the Death Valley fault zone  

NASA Astrophysics Data System (ADS)

This study presents the first detailed tephrochronologic study of the central Death Valley area by correlation of a Nomlaki-like tuff (>3.35 Ma), tuffs of the Mesquite Spring family (3.1 -- 3.35 Ma), a tuff of the lower Glass Mountain family (1.86 -- 2.06 Ma), and tephra layers from the upper Glass Mountain family (0.8 -- 1.2 Ma), the Bishop ash bed (0.76 Ma), the Lava Creek B ash bed (~0.66 Ma), and the Dibekulewe ash bed (~0.51 Ma). Correlation of these tuffs and tephra layers provides the first reliable numeric-age stratigraphy for late Cenozoic alluvial fan and lacustrine deposits for Death Valley and resulted in the naming of the informal early to middle Pleistocene Mormon Ploint formation. Using the numeric-age stratigraphy, the Death Valley fault zone (DVFZ) is interpreted to have progressively stepped basinward since the late Pliocene at Mormon Point and Copper Canyon. The Mormon Point turtleback or low-angle normal fault is shown to have unequivocal late Quaternary slip at its present low angle dip. Tectonic geomorphic analysis indicates that the (DVFZ) is composed of five geomorphic segments with the most persistent segment boundaries being the en-echelon step at Mormon Point and the bedrock salient at Artists Drive. Subsequent geomorphic studies resulting from the numeric-age stratigraphy and structural relations include application of Gilberts field criteria to the benches at Mormon Point indicating that the upper bench is a lacustrine strandline and the remaining topographically-lower benches are fault scarps across the 160--185 ka lake abrasion platform. In addition, the first known application of cosmogenic 10Be and 26Al exposure dating to a rock avalanche complex south of Badwater yielded an age of 29.5 +/- 1.9 ka for the younger avalanche. The 28 meter offset of the older avalanche may be interpreted as post-160--185 ka yielding a 0.1 mm/year slip rate, or post-29.5 +/- 1.9 ka yielding a maximum slip rate of 0.9 nun/year for the DVFZ. A consequence of these studies is the hypothesis that the turtleback or low-angle normal faults represent a thermally-warped detachment fault related to the Black Mountains igneous complex and do not conform with the present domino or a rolling-hinge models of low-angle normal fault development.

Knott, Jeffrey Rayburn

80

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

81

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

82

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

83

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

84

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

85

Pleistocene subglacial tunnel valleys in the central North Sea basin: 3-D morphology and evolution  

NASA Astrophysics Data System (ADS)

Four phases of cross-cutting tunnel valleys imaged on 3-D seismic datasets are mapped within the Middle-Late Pleistocene succession of the central North Sea basin (Witch Ground area). In plan the tunnel valleys form complex anastomosing networks, with tributary valleys joining main valleys at high angles. The valleys have widths ranging from 250 to 2300 m, and base to shoulder relief varying between 30 and 155 m, with irregular long-axis profiles characteristic of erosion by water driven by glaciostatic pressures. The youngest phase of tunnel valleys are smaller and have a thinner infill than the older generations. The fill of the larger valleys comprises three seismic facies, the lowermost of which has high amplitudes and is discontinuous. The middle facies consists of wedge-shaped packages of low-angle dipping reflectors and is overlain by a facies characterised by sub-horizontal reflectors, which onlap the valley margins. The seismic character, and comparison with lithologies identified in other northwest European Pleistocene tunnel valleys both onshore and offshore, suggests that the lower two seismic facies are most likely sand and gravel-dominated, while the uppermost facies consists of glaciolacustrine and marine muds. The 3-D morphology of the valley margins combined with the geometry of the infill packages suggest that episodic discharge of subglacial meltwater was responsible for incising the valleys and depositing at least some of the infill. Proglacial glaciofluvial deposits are inferred to account for some of the fill overlying the subglacial deposits. Glaciolacustrine and marine muds filled remaining valley topography as the ice sheet retreated. The preserved valley margins are shown to be time-transgressive erosion surfaces that record changes in geometry of the tunnel valley system as it evolved through time, implying that valleys associated with each ice-sheet advance/retreat cycle were dynamic and probably long-lived. Within the constraints of the existing stratigraphy the oldest tunnel valleys in the Witch Ground area of the central North Sea are most likely to be Marine Isotope Stage (MIS) 12 (Elsterian, ca. 470 ka) in age and the youngest pre-MIS 5e (last interglacial, ca. 120 ka). If each tunnel valley phase was formed during the retreat of a major ice sheet then four glaciations with ice coverage of the central North Sea are recorded in the pre-Weichselian, Middle-Late Pleistocene stratigraphy. Copyright

Lonergan, Lidia; Maidment, Susannah C. R.; Collier, Jenny S.

2006-12-01

86

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...

87

Particulate Air Pollution and Morbidity in the California Central Valley: A High Particulate Pollution Region.  

National Technical Information Service (NTIS)

The purpose of this study was to evaluate the relationship between particulate air pollution and morbidity among the Kaiser Permanente (KP) membership who reside in the Central Valley (CV) of California. Daily augmented particulate matter (PM) monitoring ...

S. K. Van Den Eeden C. P. Quesenberry J. Shan F. Lurmann

2002-01-01

88

Central Valley Project Municipal and Industrial Water Shortage Policy Scoping Report.  

National Technical Information Service (NTIS)

This report documents the Central Valley Project (CVP) Municipal and Industrial (M&I) Water Shortage Policy (WSP) scoping activities. The Bureau of Reclamation, the National Environmental Policy Act (NEPA) lead agency, plans to prepare an Environmental Im...

2011-01-01

89

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

Federal Register 2010, 2011, 2012, 2013

...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices that...evaluating the adequacy of all water conservation plans developed by...

2011-03-08

90

75 FR 70020 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013

...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices that...evaluating the adequacy of all water conservation plans developed by...

2010-11-16

91

77 FR 33240 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013

...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices that...evaluating the adequacy of all water conservation plans developed by...

2012-06-05

92

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

Federal Register 2010, 2011, 2012, 2013

...District. Kaweah Delta Water Conservation District. To meet the requirements...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices...

2011-08-31

93

75 FR 38538 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013

...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices that...evaluating the adequacy of all water conservation plans developed by...

2010-07-02

94

77 FR 64544 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013

...are considered the same as Water Conservation Plans. The above entities...office on Central Valley Project water conservation best management practices that...evaluating the adequacy of all water conservation plans developed by...

2012-10-22

95

Is the Central Valley of Costa Rica a genetic isolate?  

PubMed

In the last decade, the Costa Rican Central Valley population (CRCV), has received considerable scientific attention, attributed in part to a particularly interesting population structure. Two different and contradictory explanations have emerged: (1) An European-Amerindian-African admixed population, with some regional genetic heterocigosity and moderate degrees of consanguinity, similar to other Latin-American populations. (2) A genetic isolate, with a recent founder effect of European origin, genetically homogeneous, with a high intermarriage rate, and with a high degree of consanguinity. Extensive civil and religious documentation, since the settlement of the current population, allows wide genealogy and isonymy studies useful in the analysis of both hypotheses. This paper reviews temporal and spatial aspects of endogamy and consanguinity in the CRCV as a key to understand population history. The average inbreeding coefficients (a) between 1860 and 1969 show a general decrease within time. The consanguinity in the CRCV population is not homogeneous, and it is related to a variable geographic pattern. Results indicate that the endogamy frequencies are high but in general it was not correlated with a values. The general tendency shows a consanguinity decrease in time, and from rural to urban communities, repeating the tendencies observed in other countries with the same degree of development, and follows the general Western World tendency. Few human areas or communities in the world can be considered true genetic isolates. As shown, during last century, the CRCV population has had consanguinity values that definitively do not match those of true genetic isolates. A clear knowledge of the Costa Rican population genetic structure is needed to explain the origin of genetic diseases and its implications to the health system. PMID:17361557

Morera, Bernal; Barrantes, Ramiro

2004-09-01

96

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

97

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

98

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

99

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

100

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 activity—which 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

101

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

102

The depositional environments and petrography of the Stirling Quartzite Death Valley Region, California and Nevada  

NASA Astrophysics Data System (ADS)

The Stirling Quartzite is a relatively unmetamorphosed, predominantly clastic formation of latest Precambrian age which accumulated during the early stages of a Cordilleran miogeocline. It is extensively exposed throughout the Death Valley region of California and Nevada. The formation was divided into fine members A-E. The stratigraphic arrangement of the members is such that the lower and upper halves of the formation are approximate mirror images of each other with respect to their physical characteristics. The overall coarse to fine to coarse grain-size pattern which characterizes the stratigraphy of the Stirling Quartzite reflects a change from a relatively high energy depositional environment to a relatively low energy one and back again. Comparison of the Stirling paleocurrent trends with a paleogeographic map of the Pahrump Group (Wright and others, 1974), suggests that the structural template which is associated with the Amargosa aulacogen also influence the paleogeography of the Stirling Quartzite.

Wertz, W. E.

103

Early Tertiary magmatism and probable Mesozoic fabrics in the Black Mountains, Death Valley, California  

NASA Astrophysics Data System (ADS)

We report two early Tertiary U-Pb zircon ages for pegmatite from the Black Mountains of Death Valley, California. These ages, 54.7 ± 0.6 Ma and 56 ± 3 Ma, are unique for much of southeastern California. The samples belong to a pegmatite suite that occupies part of the footwall of the Badwater turtleback, a late Tertiary extensional feature; similar but undated pegmatite intrudes the footwalls of the Copper Canyon and Mormon Point turtlebacks farther south. The pegmatite suite demonstrates that fabric development on the turtlebacks was at least a two-stage process. Fabrics cut by these pegmatites likely formed during the Mesozoic, whereas those that involve them formed during late Tertiary extension.

Miller, Martin G.; Friedman, Richard M.

1999-01-01

104

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

105

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

106

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

107

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

108

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

109

Gathered wild food plants in the upper valley of the Serchio River (Garfagnana), Central Italy  

Microsoft Academic Search

A study of the traditional gathered food plants in the upper valley of the Serchio river (Garfagnana), Lucca Province, north-west\\u000a Tuscany, central Italy, was carried out. One hundred thirty-three species (including fungi), belonging to 48 families, were\\u000a encountered. The geographical isolation of the valley and the survival of old gastronomic traditions have permitted a rich\\u000a popular knowledge to be main-tained.

Andrea Pieroni

1999-01-01

110

BAGC.m: Three dimensional gravity modeling software with an application in Southern Death Valley, CA  

NASA Astrophysics Data System (ADS)

Basin Anomaly Gravity Calculator (BAGC.m) is a 3D interactive gravity modeling package designed to create, edit, and calculate the gravitational attraction of basin models entirely within the MATLAB(TM) environment. Gravity anomalies are calculated using the Rectangular Prism Method (Bott, 1960; Kane, 1962; and Plouff, 1966) which subdivides earth models into regularly spaced rectangular prisms. This approach requires large 3D matrices to store most realistic earth models. The process of model editing is simplified by storing basins as 2D gridded files which define the depth to the boundary between basement rock and sedimentary fill for each model cell. In order to minimize computation time, BAGC.m calculates and stores the gravitational attraction of each cell so that when the model is edited only those cells that change need to be recalculated. The performance of BAGC.m was tested by comparing the gravity anomaly produced by a modeled sphere of radius 4.5 km at a depth of 4.5 km with its analytical solution. The tests indicate that BAGC.m reproduces the analytical solution with an error of 0.6% for a sample spacing of 60 m which corresponds to 7.07x10-6% of the volume of the sphere. BAGC.m was used to calculate the gravitational attraction of a regional basin depth model of Death Valley developed by Blakely and Ponce (2001). Results were compared to a new high precision gravity data set and indicate that the structures within the Southern Death Valley Fault Zone (SDVFZ) are more complex than predicted by the regional basin depth model. However, the program did calculate the contributions of the basin fill to the regional gravity field based on that depth model.

Eslick, Brian Eugene

111

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

112

Hydrogeological characterization of Gold Valley: an investigation of precipitation recharge in an intermountain basin in the Death Valley region, California, USA  

NASA Astrophysics Data System (ADS)

Gold Valley is typical of intermountain basins in Death Valley National Park (DVNP), California (USA). Using water-balance calculations, a GIS-based analytical model has been developed to estimate precipitational infiltration rates from catchment-scale topographic data (elevation and slope). The calculations indicate that groundwater recharge mainly takes place at high elevations (>1,100 m) during winter (average 1.78 mm/yr). A resistivity survey suggests that groundwater accumulates in upstream compartmentalized reservoirs and that the groundwater flows through basin fill and fractured bedrock. This explains the relationship between the upstream precipitational infiltration in Gold Valley and the downstream spring flow in Willow Creek. To verify the ability of local recharge to support high-flux springs in DVNP, a GIS-based model was also applied to the Furnace Creek catchment. The results produced insufficient total volume of precipitational infiltration to support flow from the main high-flux springs in DVNP under current climatic conditions. This study introduces a GIS-based infiltration model that can be integrated into the Death Valley regional groundwater flow model to estimate precipitational infiltration recharge. In addition, the GIS-based model can efficiently estimate local precipitational infiltration in similar intermountain basins in arid regions provided that the validity of the model is verified.

Abdulaziz, Abdulaziz M.; Hurtado, José M.; Faid, Abdalla

2012-06-01

113

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

114

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

National Technical Information Service (NTIS)

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 kil...

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

2001-01-01

115

Preliminary Estimates of Spatially Distributed Net Infiltration and Recharge for the Death Valley Region, Nevada-California.  

National Technical Information Service (NTIS)

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 defi...

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

2002-01-01

116

Study of Hypersaline Deposits and Analysis of Their Signature in Airborne and Spaceborne SAR Data: Example of Death Valley, California  

Microsoft Academic Search

Field measurements of dielectric properties of hypersaline deposits were realized over an arid site located in Death Valley, CA. The dielectric constant of salt and water mixtures is usually high but can show large variations, depending on the considered salt. We confirmed values observed on the field with laboratory measurements and used these results to model both the amplitude and

Yannick Lasne; Philippe Paillou; Anthony Freeman; Tom Farr; Kyle McDonald; Gilles Ruffie; Jean-Marie Malezieux; Bruce Chapman

2009-01-01

117

Delineation and Hydrologic Effects of a Gasoline Leak at Stovepipe Wells Hotel, Death Valley National Monument, California.  

National Technical Information Service (NTIS)

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...

A. Buono E. M. Packard

1982-01-01

118

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

NASA Astrophysics Data System (ADS)

Springs in the Furnace Creek area (Texas, Travertine, and Nevares Springs) of Death Valley National Park exhibit high discharge rates and depleted ?18O VSMOW (˜-13‰) and ?D VSMOW (˜-102‰) values. Isotopic depletion of this magnitude and large spring fluxes (˜10,000 L/min) suggests that modern local recharge in the arid Furnace Creek drainage cannot be responsible for spring fluxes. An alternate explanation, interbasin flow, is difficult to envisage due to the stratigraphic and structural relationships of bedrock in intervening ranges, although it is the most common conceptual model for Furnace Creek spring flows. High-flux springs at Furnace Creek nonetheless respond modestly to modern climate in terms of discharge rate and isotopic composition. Hydrographs show a climate response and variations in time-series stable isotope data of widely spaced springs track one another. Small, but measurable quantities of tritium (<0.2 TU) were found at Nevares Spring, also suggesting a component of modern recharge. Thus, whatever the main source of water for these springs may be, there appears to be a subtle, but recent climatic influence. Estimates of flow at nearby mountain springs produce discharge rates per square kilometer of catchment that, by analogy, could support from 20 to 300% of the flow at large Death Valley springs under the current climate. Yet, 14C model ages suggest valley-bottom springs at Furnace Creek (5500-14,500 yr) contain a large component of older water, suggesting that much of the water was recharged during a pluvial period (Younger Dryas?) when net infiltration would have been much higher and isotopically depleted. 14C model ages are also of similar age, or younger, than many 'up gradient' waters, rather than being older as would be expected for interbasin flow. Chemical evolution models of solutes are consistent with both local recharge and interbasin transfer from Ash Meadows. However, when considered with isotopic constraints, interbasin flow becomes obviously untenable. Estimates of the thickness of alluvium and semi-consolidated Tertiary units in the Furnace Creek drainage seem to provide adequate storage, confinement, and upward leakage to accommodate current discharge. Thus, although Death Valley is the ultimate discharge location for regional groundwaters in terms of potential, careful study of these springs suggests that most of their flux is supported by local pluvial recharge, suggesting that a careful re-evaluation of the interbasin transfers be conducted on a case-by-case basis. Furthermore, regional flow models that are built on the concept of interbasin flow provide boundary flux conditions for site-scale models for the proposed nuclear waste repository at Yucca Mountain, Nevada. Thus, site-scale models may over-predict the potential transport of waste from the Yucca Mountain facility.

Anderson, Katherine; Nelson, Stephen; Mayo, Alan; Tingey, David

2006-05-01

119

Winter fog is decreasing in the fruit growing region of the Central Valley of California  

NASA Astrophysics Data System (ADS)

Central Valley of California is home to a variety of fruit and nut trees. These trees account for 95% of the U.S. production, but they need a sufficient amount of winter chill to achieve rest and quiescence for the next season's buds and flowers. In prior work, we reported that the accumulation of winter chill is declining in the Central Valley. We hypothesize that a reduction in winter fog is cooccurring and is contributing to the reduction in winter chill. We examined a 33 year record of satellite remote sensing to develop a fog climatology for the Central Valley. We find that the number of winter fog events, integrated spatially, decreased 46%, on average, over 32 winters, with much year to year variability. Less fog means warmer air and an increase in the energy balance on buds, which amplifies their warming, reducing their chill accumulation more.

Baldocchi, Dennis; Waller, Eric

2014-05-01

120

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

121

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

122

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

123

Late Pleistocene-Holocene Chemical Stratigraphy and Paleolimnology of the Rift Valley Lakes of Central Africa.  

National Technical Information Service (NTIS)

The interaction of climate and geology in Central Africa during Late Pleistocene and Holocene is examined. The study is based on sedimentological and limnological work on the main lakes of the Western Branch of the East African Rift Valley, particularly L...

R. E. Hecky E. T. Degens

1973-01-01

124

Spatial and Seasonal Variability of Base Flow in the Verde Valley, Central Arizona, 2007 and 2011.  

National Technical Information Service (NTIS)

Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in cooperation with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai Count...

B. D. Garner D. J. Bills

2012-01-01

125

Evaluation of the Central Valley Partnership of the James Irvine Foundation  

ERIC Educational Resources Information Center

The Central Valley Partnership (CVP) was the centerpiece of the Civic Culture Program area of the James Irvine Foundation headquartered in San Francisco. Initiated in 1996 as a "partnership for citizenship," CVP had three objectives: (1) assisting and supporting immigrants seeking citizenship; (2) promoting active civic participation throughout…

Campbell, Martha S.; Patton, Michael Quinn; Patrizi, Patricia

2005-01-01

126

Early Pleistocene Glacial Lake Lesley, West Branch Susquehanna River valley, central Pennsylvania  

Microsoft Academic Search

Laurentide glaciers extended into north central Pennsylvania repeatedly during at least the last 2 million years. Early Pleistocene glaciation extended farther south into central Pennsylvania than any subsequent glaciation, reaching the West Branch Susquehanna River (WBSR) valley. Early Pleistocene ice dammed the northeast-flowing West Branch Susquehanna River at Williamsport, forming Glacial Lake Lesley, a 100-km-long proglacial lake. In this paper,

Joan M. Ramage; Thomas W. Gardner; Ira D. Sasowsky

1998-01-01

127

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

NASA Astrophysics Data System (ADS)

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, and Braldu valleys, to elucidate the spatio-temporal scale dependencies of surface processes active in the region. These valleys were examined using geomorphic field methods, remote sensing, geomorphometry, and terrestrial cosmogenic nuclides (TCNs) surface exposure dating. The glaciers in this region have oscillated considerably throughout the Late Quaternary, and four glacial stages have been recognized including at least six glacial advances. Surface processes readjusted after glacier retreat, and ubiquitous mass movements and catastrophic landsliding transported material from steep slopes to valley bottoms, while glaciofluvial meltwater and glacier outburst floods redistributed sediment down valley. Glacier geochronology and late Holocene ages of the outburst flood deposits indicate that landscape evolution has been dominated by glaciation and paraglaciation during the late Quaternary.

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

2009-01-01

128

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

129

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 subtilis–B. 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.

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

2012-01-01

130

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

131

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

132

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

133

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

Microsoft Academic Search

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.

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

2003-01-01

134

Aminostratigraphic Correlation and Geochronology of Two Quaternary Loess Localities, Central Mississippi Valley  

NASA Astrophysics Data System (ADS)

Amino acid epimeric (aIle/Ile) values from terrestrial molluscs are used to define and correlate three aminozones in loess sequences exposed across the central Mississippi Valley, in Arkansas and Tennessee. Three superposed aminozones are defined at Wittsburg quarry, Arkansas, primarily using aIle/Ile values from total hydrolysates of the gastropod genus Hendersonia: Peoria Loess (aIle/Ile = 0.07 ± 0.01), Roxana Silt (0.14 ± 0.02), and a third loess (0.28 ± 0.06). Loess units at Wittsburg quarry can be correlated on lithologic characteristics eastward across the Mississippi Valley to the Old River section, near Memphis, Tennessee; however, only one loess unit is fossil-bearing (Peoria Loess, aIle/Ile = 0.05) at that section. Radiocarbon analyses of charcoal from the upper Roxana Silt (ca. 26,000 to 29,000 yr old) and mollusc shell carbonate from the basal Roxana Silt (ca. 39,000 yr old) are used to calibrate amino acid epimeric data for the central Mississippi Valley. These data, applied to the apparent parabolic kinetic model of R. M. Mitterer and N. Kriausakul (1989, Quaternary Science Reviews 8, 353-357), suggest an Illinoian (>120,000 yr) age for the third loess in the central Mississippi Valley that is correlative with part of the Loveland Loess in Illinois and Iowa.

Mirecki, June E.; Miller, Barry B.

1994-05-01

135

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

136

Climate change, shifting seasons, and the ecohydrology of Devils Hole, Death Valley National Park  

NASA Astrophysics Data System (ADS)

Devils Hole, a water-filled fracture in the carbonate aquifer of the Death Valley Regional Flow System, comprises an ecosystem that can serve as a bellwether of climate change. This 50 square meter pool of unknown depth is home to the only extant population of the endangered Devils Hole pupfish (Cyprinodon diabolis). A shallow shelf in the system provides the most suitable habitat for spawning, and the past pupfish population counts have been correlated to the water level in the system. Recently, however, population declines unrelated to water level have been observed. The 33° C waters of Devils Hole are near the upper threshold for most Cyprinodon species, and the shallow shelf experiences the greatest diurnal and seasonal temperature variability. The extremely limited habitat, small population (the spring, 2011 population survey counted approximately 100 individuals), and precarious nature of populations near survival thresholds combine to make the system exceptionally susceptible to the impacts of climate change. A hydrodynamic model of the shallow shelf was developed to simulate thermal convection in response to a number of energy fluxes, including climatic drivers such as air temperature and solar radiation. Simulations of current conditions demonstrate seasonal and diurnal changes in the temperature of the water and the substrate in which adult pupfish spawn, eggs hatch, and larvae develop. The simulated convection patterns also influence the oxygen dynamics, nutrient cycling, and the food web of the ecosystem. Simulations of future conditions using a delta change methodology point towards changes in the seasonal cycles, which may limit or shift the reproductive season of the species.

Hausner, M. B.; Wilson, K. P.; Gaines, D. B.; Suarez, F. I.; Tyler, S. W.

2011-12-01

137

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

138

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, III, J. C.; Wells, S. G.

2002-01-01

139

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.

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

2012-01-01

140

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

141

Irrigation in California's Central Valley strengthens the southwestern U.S. water cycle  

NASA Astrophysics Data System (ADS)

Characterizing climatological and hydrological responses to agricultural irrigation continues to be an important challenge to understanding the full impact of water management on the Earth's environment and hydrological cycle. In this study, we use a global climate model, combined with realistic estimates of regional agricultural water use, to simulate the local and remote impacts of irrigation in California's Central Valley. We demonstrate a clear mechanism that the resulting increase in evapotranspiration and water vapor export significantly impacts the atmospheric circulation in the southwestern United States, including strengthening the regional hydrological cycle. We also identify that irrigation in the Central Valley initiates a previously unknown, anthropogenic loop in the regional hydrological cycle, in which summer precipitation is increased by 15%, causing a corresponding increase in Colorado River streamflow of ~30%. Ultimately, some of this additional streamflow is returned to California via managed diversions through the Colorado River aqueduct and the All-American Canal.

Lo, Min-Hui; Famiglietti, James S.

2013-01-01

142

Biological Assessment of Urban and Agricultural Streams in the California Central Valley  

Microsoft Academic Search

This project was designed to establish baseline aquatic biological community structure and physical habitat conditions in\\u000a select wadeable streams within the California Central Valley. A secondary objective was to evaluate possible water quality\\u000a differences between site types and seasons. Two agricultural and two urban streams were monitored in spring and fall for two\\u000a consecutive years beginning in the fall of

Juanita Bacey; Frank Spurlock

2007-01-01

143

Biological Assessment on the Continued Long-term Operations of the Central Valley Project and the State Water Project.  

National Technical Information Service (NTIS)

The Bureau of Reclamation (Reclamation) and the California Department of Water Resources (DWR) propose to operate the Central Valley Project (CVP) and State Water Project (SWP) to divert, store, re-divert, and convey CVP and SWP (Project) water consistent...

2008-01-01

144

Final Environmental Assessment: Community Water Company of Green Valley Central Arizona Project Water Delivery System Pima County, Arizona  

National Technical Information Service (NTIS)

An initial draft Environmental Assessment (DEA) for the Community Water Company of Green Valleys (CWC) proposed construction and operation of its Central Arizona Project (CAP) Water Delivery System and Recharge Facility was made available for a public rev...

2010-01-01

145

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

Federal Register 2010, 2011, 2012, 2013

...Water Management Plans are considered the same as Water Conservation Plans. DATES: Submit written comments by April...and administer an office on Central Valley Project water conservation best management practices (BMPs) that shall...

2011-03-25

146

A Geophysical Survey of the Quaternary Beatty Junction Paleolake Shoreline Deposit, Death Valley National Park, California  

NASA Astrophysics Data System (ADS)

We conducted a ground-penetrating radar (GPR) and seismic refraction survey of the Beatty Junction Shoreline Deposit in Death Valley National Park in March 2005. The deposit is a beach barrier bar approximately 500 m long, 50 m wide, and 5 m high, at an elevation of about 30 m above sea level and corresponds to a relict shoreline of the former Lake Manly (Orme and Orme, Phys. Geog., 12, pp. 334-346, 1980). The bar is oriented WSW-ENE, slopes to the east and is cut by the Beatty Junction Road. The longitudinal profile of the bar slopes to the east and is slightly concave upward. A total of 730 m of GPR data were recorded, including a longitudinal line 360 m in length, oriented along the crest of the bar, and four transverse lines, each approximately 100 m long. A hammer seismic refraction line was also recorded along the crest of the bar, and yielded a 3-layer model consisting of a surface layer about 1 m thick with a velocity of 200 m/s, a second layer 4-9 m thick with a velocity of 700 m/s, and a basal unit with a velocity of 1500 m/s. The uppermost layer apparently corresponds to an unconsolidated surface veneer of coarse gravel that has been winnowed to form desert pavement. The second layer is presumably sand and gravel that forms the main portion of the bar, and which thins in the longitudinal direction, from 9 m in the west to 4 m in the east. The third, basal layer represents older, more consolidated fan sediments. Shallow reflectors on the lakeward side of two of the transverse GPR lines have a distinct step-like appearance that may represent berms. All GPR lines show a thin surface layer, about 1 m thick, that unconformably covers all reflectors in the interior of the deposit, similar to the Hanaupah Shoreline Deposit at Tule Spring, described by Ibbeken and Warnke ( J. Paleolimnology, 23, pp. 439-447, 2002). The age of the deposit is given as 153 ± 12 Ka, late in Marine Isotope Stage 6 (Orme and Orme, 1991). Since this age range overlaps with that given by Machette et al. for the Tule Spring deposit ( GSA Abstracts with Programs, 34, pp. 257-258, 2003), we consider both deposits nearly time equivalent, deposited near or during Termination II.

Craig, M.; Warnke, D.; Teitler, L.; Narvaez, R.

2005-12-01

147

Monitoring The Dynamics Of Hyper-Saline Environments With Polarimetric SAR: Death Valley, California Example  

NASA Astrophysics Data System (ADS)

Soil salinization in arid and semi-arid regions still remains one of the most important threats not only for socio-economical issues when dealing with water ressources management, but also for ecological matters such as: desertification, climate changes, and biomass reduction. Then, monitoring and mapping of soil salinity distribution represent today a key challenge in our understanding of such environmental processes. Being highly dependent on the dielectric properties of soils, synthetic aperture radar (SAR) appears to be an efficient tool for the remote sensing of hyper-saline environments. More precisely, the influence of saline deposits on SAR imagery lies in the solubility and ionic properties of the minerals which strongly influence both real and imaginary parts of the complex permittivity of such deposits, and thus the radar backscattering coefficient. Based on temporal series acquired with spaceborne SAR systems (ALOS/PALSAR, SIR-C) over the Death Valley (CA), we show that the copolarized backscattering ratio and phase difference derived from SAR data can be used as suitable indicators to monitor the dynamics of hyper-saline deposits. In particular, we propose these copolar parameters to follow the variations in the dielectric properties of moistened and salt-affected soils on a seasonal time scale because of the close relationship between the salinity (governed by the soil moisture content) and the complex permittivity of the soils. We also highlight a strong temporal correlation between the copolar parameters and weather data since precipitation events control the soil moisture and salinity. In order to allow for a better interpretation of the saline deposits signatures observed on SAR data, we also perform analytical simulations of the radar backscattering associated with saline deposits by means of the IEM scattering model. Using laboratory and in~ situ dielectric measurements as input parameters, we simulate the copolar ratio and phase difference as function of the complex permittivity and surface roughness. Successfully reproducing the observed signature, our results indicate that the analysis of SAR data could also account for the monitoring and understanding of seasonal changes of evaporitic basins through a close correlation between the soil moisture and surface roughness related to the desiccation processes. Such results are of great interest for soil salinity monitoring and the detection of small amounts of subsurface water mixed with evaporites, not only for arid terrestrial surfaces but also for planetary missions, particularly the exploration of Mars. Both of the observation and simulation aspects of our methodology will be thouroughly described at time of the presentation as well as the sustaining measurement technique. We will also present preliminary results derived from the first high-resolution image acquired with the UAVSAR sensor operated by NASA/JPL/CalTech.

Lasne, Y.; McDonald, K.; Paillou, P.; Freeman, A.; Chapman, B.; Farr, T.; Ruffié, G.; Malézieux, J.

2008-12-01

148

Morphometric differences in debris flow and mixed flow fans in eastern Death Valley, CA  

NASA Astrophysics Data System (ADS)

Geomorphological features are best examined through direct measurement and parameterization of accurate topographic data. Fine-scale data are therefore required to produce a complete set of elevation data. Airborne Laser Swath Mapping (ALSM) data provide high-resolution data over large spatially continuous areas. The National Center for Advanced Laser Mapping (NCALM) collected ALSM data for an area along the eastern side of Death Valley extending from slightly north of Badwater to Mormon Point. The raw ALSM data were post-processed and delivered by NCALM in one-meter grid nodes that we converted to one-meter raster data sets. ALSM data are used to assess variations in the dimensions of surficial features found in 32 alluvial fans (21 debris flow and 11 mixed flow fans). Planimetric curvature of the fan surfaces is used to develop a topographic signature to distinguish debris flow from mixed flow fans. These two groups of fans are identified from field analysis of near vertical exposures along channels as well as surficial exposures at proximal, medial, and distal fan locations. One group of fans exhibited debris flow characteristics (DF), while the second group contained a mixture of fluid and debris flows (MF). Local planimetric curvature of the alluvial fan surfaces was derived from the one-meter DEM. The local curvature data were reclassified into concave and convex features. This sequence corresponds to two broad classes of fan features: channels and interfluves. Thirty random points were generated inside each fan polygon. The length of the nearest concave-convex (channel-interfluve) couplet was measured at each point and the percentage of convex and concave pixels in a 10m box centered on the random point was also recorded. Plots and statistical analyses of the data show clear indication that local planimetric curvature can be used as a topographic signature to distinguish between the varying formative processes in alluvial fans. Significant differences in the lengths of the channel and interfluve couplets and the percent pixels per unit area have been identified between the two fan groups. In general, shorter distances were found in the mixed flow fans. This finding can be attributed to primary and secondary erosional processes leading to a higher degree of dissection in the MF fan surfaces than was identified in the DF fans. The clast-rich deposits of the DF fan are more resistant to secondary erosional processes and overtopping of the levees likely leads to filling of older incised debris flow channels.

Wasklewicz, T. A.; Whitworth, J.

2004-12-01

149

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

150

Death Valley turtlebacks: Mesozoic contractional structures overprinted by Cenozoic extension and metamorphism beneath syn-extensional plutons  

NASA Astrophysics Data System (ADS)

The term turtleback was first coined to describe the curvilinear fault surfaces that produced a distinctive geomorphic form in the Black Mountains east of Death Valley, and although it was decades before their full significance was appreciated, they remain one of the most distinctive features of the extensional structure of the Death Valley region. Historically the interpretation of the features has varied markedly, and misconceptions about their character continue to abound, including descriptions in popular field guides for the area. It the 1990's, however, the full history of the systems began to be apparent from several key data: 1) the dating of the plutonic assemblage associated with the turtlebacks demonstrated that late Miocene, syn-extensional plutonism was fundamental to their formation; 2) the plutonic assemblage forms an intrusive sheet structurally above the turtlebacks, indicating a tie between much of the high grade metamorphism and Cenozoic plutonism; 3) a modern analog for the syn-extensional plutonism in the Black Mountains was recognized beneath Death Valley with the imaging of a mid-crustal magma body; 4) the Neogene structural history was worked out in the turtlebacks showing that folding of early-formed shear zones formed the turtleback anticlinoria but overprinting by brittle faults produced the final form as they cut obliquely across the older structure; and 5) the pre-extensional structural history was clarified, demonstrating that Mesozoic basement-involved thrust systems are present within the turtlebacks, but have been overprinted by the extensional system. An unresolved issue is the significance of Eocene U-Pb dates for pegmatites within the region, but presumably these relate somehow to the pre-extensional history. Miller and Pavlis (2005; E. Sci. Rev.) reviewed many features of the turtlebacks, and our working model for the region is that the turtlebacks originated as mid-crustal ductile-thrust systems within the Cordilleran fold-thrust belts. Our work to the east of Death Valley suggests these thrusts were part of a NW trending thrust system that overprinted an older NE trending fold-thrust system that tracks into the Death Valley region from Nevada. These NW trending thrusts probably underlie all of the southern Black Mountains (south of the turtlebacks) and we suggest that pre-extensional structural relief along these basement thrusts placed basement at shallow crustal levels throughout what is now the Black Mountains; a conclusion consistent with the absence of rocks younger than Cambrian beneath Tertiary unconformities throughout the southern Death Valley region. In Late Miocene time, a major detachment system formed and the turtlebacks represent a mid-crustal shear zone developed during that time period, but this system is older, and structurally beneath younger detachments systems that comprise the Amargosa fault system. During motion on the detachment, an ~2km thick plutonic sheet was emplaced along the shear zone forming the Miocene plutonic assemblages of the Black Mountains, and produced upper amphibolite facies metamorphic assemblages along the floor of the pluton in what are now the Copper Canyon and Mormon Point turtlebacks, but the Badwater Turtleback escaped this metamorphism due to a different structural position. Motion continued along the floor of the pluton but syn-extensional folding produced structural relief along folds with axes parallel to the extension direction. Ultimately a new detachment system cut obliquely across the older extensional system, removing the roof of the pluton, but cutting down to its floor in the turtlebacks. This fault system formed a complex detachment system updip in the famous 'Amargosa Chaos', and removing the entire cover sequence from the Black Mountains (~10-12km of crustal section). The turtlebacks are therefore a composite structure in which extension contemporaneous with folding, presumably as a result of distributed transcurrent motion during extension, was critical to their formation. In addition, syn-tectonic plutonism played a key

Pavlis, T. L.; Miller, M.; Serpa, L.

2008-07-01

151

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

152

Surficial Geologic Mapping Using Digital Techniques Reveals Late-Phase Basin Evolution and Role of Paleoclimate, Death Valley Junction 30' × 60' Quadrangle, California and Nevada  

NASA Astrophysics Data System (ADS)

The recently released surficial geologic map of the Death Valley Junction 30' x 60' quadrangle at 1:100,000 scale (USGS SIM 3013) was simultaneously mapped and compiled using digital photogrammetric methods. The map area covers the central part of Death Valley and adjacent mountain ranges—the Panamint Range on the west and the Funeral Mountains on the east—as well as areas east of Death Valley including some of the Amargosa Desert, the Spring Mountains, and Pahrump Valley. We mapped six alluvial units, an eolian unit, three playa or playa-related units, lacustrine beach deposits, colluvium, and marl. Interpretation of surface morphology, tone, relative height, and map pattern in air photos enabled us to differentiate among the alluvial units, which make up about 80 percent of the surficial deposits in the map area. Systematic variations in alluvial surface morphology with age permit us to map and correlate geomorphic surfaces. Surface morphology is a product of depositional and post-depositional processes. Lithologic variations across the map area influence the tone of the alluvial units. Although young alluvial units are often light-toned due to an absence or paucity of rock varnish, they may appear dark where the source rocks are dark. Lithology also influences the development of rock varnish; fine-grained or aphanitic rocks, such as quartzite or basalt, tend to become varnished more quickly than rocks such as limestone or granite. Granite commonly disaggregates to grus before becoming varnished and limestone becomes etched. Relative height (topographic position) is useful for mapping in individual drainage basins near range fronts, but basinward, especially in tectonically inactive areas, most surfaces grade to the same base level, and relative height differs little among the alluvial units. Faulting, both the magnitude and location, also affects the map pattern of alluvial units. As faulting uplifts ranges relative to the basins, streams adjust to new base levels, abandoning and incising older alluvial units, thus preserving them on the footwall block of the fault. In tectonically inactive areas, streams continue to grade to the same level or aggrade, thus progressively burying older alluvial units. Therefore, map pattern of alluvial units is an important tool to evaluate late-phase basin evolution in the Basin and Range province. Determining the age of these alluvial units enables us to examine the role of paleoclimate during deposition. Six terrestrial cosmogenic-nuclide (TCN) 36Cl depth-profile dates of unit Qai fans along the west side of Death Valley range from about 40 ka to 100 ka (with a mean age of about 65 ka) and thus post-date the marine oxygen-isotope stage (MIS) 6 cycle of Pleistocene Lake Manly, but predate the lesser, MIS 2 successor. TCN 36Cl depth-profile dating establishes the age of a lacustrine bar complex at 30 m above sea level on the north side of Hanaupah Canyon to be 130 (+75/-39) ka and correlates with a deep lake at MIS 6. This bar predates units mapped as Qai and thus provides an important stratigraphic datum.

Slate, J.; Berry, M.; Menges, C. M.

2010-12-01

153

Tributary-stream infiltration in Marsh Creek Valley, north-central Pennsylvania  

USGS Publications Warehouse

The geohydrology of infiltration from five tributary streams along a 3.6-mile reach of Marsh Creek valley in north-central Pennsylvania was investigated during 1983-85. Marsh Creek valley is underlain by up to 100 feet of stratified drift that overlies Devonian bedrock. The stratified drift is overlain by up to 30 feet of alluvial-fan deposits near the tributary streams. Four of the five tributary streams lose large amounts of water to the stratified-drift aquifer in Marsh Creek valley. Along reaches away from the valley wall, infiltration losses from the streams averaged about 2 cubic feet per second per 1,000 feet of wetted channel length. Estimated hydraulic conductivity of the deposits near these streams ranges from 31 to 100 feet per day and averages 61 feet per day. Silty beds of lower permeability near the streams may significantly affect infiltration. The low permeability of the sediments near the fifth stream, which probably consist largely of fine-grained alluvium and swamp deposits, may account for the lack of infiltration losses along this stream. Tributary-stream infiltration accounted for more than 70 percent of the estimated recharge to the stratified-drift aquifer along the reach investigated during water year 1985, in which annual precipitation was below average. The sources of recharge and their estimated rates were: (1) direct infiltration of precipitation on the valley, 1.7 cubic feet per second; (2) unchanneled runoff and ground-water inflow from the uplands, 2.7 cubic feet per second; and (3) tributary-stream infiltration from Asaph Run, 3.7 cubic feet per second, Straight Run, 3.7 cubic feet per second, Dantz Run, 1.2 cubic feet per second, and Canada Run, 1.9 cubic feet per second. The temporal variation in recharge from tributary-stream infiltration greatly affects drawdowns caused by pumping from the wellfield at the National Fisheries Research and Development Laboratory near Straight Run.

Williams, John H.

1991-01-01

154

Source-area dynamics recorded in Pennsylvanian to early Permian Keeler Canyon Formation, Death Valley-Owens Valley region, California  

SciTech Connect

The middle to upper Keeler Canyon Formation exposed in east-central California is composed of up to 1200 m of mixed-carbonate/siliciclastic gravity-flow deposits that accumulated in a basin inherited from the Antler foreland basin. Based on lithologic and facies associations and on paleocurrent data, this basinal succession is divisible into two distinct depositional sequences related to the evolution of two separate source areas.

Yose, L.A.; Miller, R.P.; Heller, P.L.

1989-04-01

155

Source-area dynamics recorded in Pennsylvanian to early Permian Keeler Canyon Formation, Death Valley-Owens Valley region, California  

Microsoft Academic Search

The middle to upper Keeler Canyon Formation exposed in east-central California is composed of up to 1200 m of mixed-carbonate\\/siliciclastic gravity-flow deposits that accumulated in a basin inherited from the Antler foreland basin. Based on lithologic and facies associations and on paleocurrent data, this basinal succession is divisible into two distinct depositional sequences related to the evolution of two separate

L. A. Yose; R. P. Miller; P. L. Heller

1989-01-01

156

The role of Thurwieser rock avalanche in the geomorphological evolution of Zebrù 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 Marè Valley, a tributary located in upper part of Zebrù 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 Zebrù 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 Zebrù 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 Zebrù glacier, flowing from the Mt Zebrù 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

157

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

158

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

159

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

160

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

161

Geochemistry of Mesozoic plutons, southern Death Valley region, California: Insights into the origin of Cordilleran interior magmatism  

USGS Publications Warehouse

Mesozoic granitoid plutons in the southern Death Valley region of southeastern California reveal substantial compositional and isotopic diversity for Mesozoic magmatism in the southwestern US Cordillera. Jurassic plutons of the region are mainly calc-alkaline mafic granodiorites with ??Ndi of -5 to -16, 87Sr/86Sri of 0.707-0.726, and 206Pb/204Pbi of 17.5-20.0. Cretaceous granitoids of the region are mainly monzogranites with ??Ndi of -6 to -19, 87Sr/86Sri of 0.707-0.723, and 206Pb/204Pbi of 17.4-18.6. The granitoids were generated by mixing of mantle-derived mafic melts and pre-existing crust - some of the Cretaceous plutons represent melting of Paleoproterozoic crust that, in the southern Death Valley region, is exceptionally heterogeneous. A Cretaceous gabbro on the southern flank of the region has an unuasually juvenile composition (??Ndi -3.2, 87Sr/86Sri 0.7060). Geographic position of the Mesozoic plutons and comparison with Cordillera plutonism in the Mojave Desert show that the Precambrian lithosphere (craton margin) in the eastern Mojave Desert region may consists of two crustal blocks separated by a more juvenile terrane.

Ramo, O. T.; Calzia, J. P.; Kosunen, P. J.

2002-01-01

162

Slip Rates, Recurrence Intervals and Earthquake Event Magnitudes for the southern Black Mountains Fault Zone, southern Death Valley, California  

NASA Astrophysics Data System (ADS)

The normal-oblique Black Mountain Fault zone (BMFZ) is part of the Death Valley fault system. Strong ground-motion generated by earthquakes on the BMFZ poses a serious threat to the Las Vegas, NV area (pop. ~1,428,690), the Death Valley National Park (max. pop. ~20,000) and Pahrump, NV (pop. 30,000). Fault scarps offset Holocene alluvial-fan deposits along most of the 80-km length of the BMFZ. However, slip rates, recurrence intervals, and event magnitudes for the BMFZ are poorly constrained due to a lack of age control. Also, Holocene scarp heights along the BMFZ range from <1 m to >6 m suggesting that geomorphic sections have different earthquake histories. Along the southernmost section, the BMFZ steps basinward preserving three post-late Pleistocene fault scarps. Surveys completed with a total station theodolite show scarp heights of 5.5, 5.0 and 2 meters offsetting the late Pleistocene, early to middle Holocene, to middle-late Holocene surfaces, respectively. Regression plots of vertical offset versus maximum scarp angle suggest event ages of <10 - 2 ka with a post-late Pleistocene slip rate of 0.1mm/yr to 0.3 mm/yr and recurrence of <3300 years/event. Regression equations for the estimated geomorphically constrained rupture length of the southernmost section and surveyed event displacements provides estimated moment magnitudes (Mw) between 6.6 and 7.3 for the BMFZ.

Fronterhouse Sohn, M.; Knott, J. R.; Bowman, D. D.

2005-12-01

163

Silurian, Devonian, and Mississippian Formations of the Funeral Mountains in the Ryan Quadrangle, Death Valley Region, California  

USGS Publications Warehouse

A composite section of the Silurian, Devonian, and Mississippian formations in the Funeral Mountains between Death Valley and Amargosa Valley is about 4,700 feet thick. The formations are in the top of a concordant, complexly faulted sequence that is about 25,000 feet thick from the highest part of the Precambrian to the Upper Mississippian. The Silurian and younger formations consist of marine dolomite and limestone that contain some regionally characteristic cherty and siliceous clastic beds as well as widely spaced fossiliferous zones. The Hidden Valley Dolomite, overlying the Ordovician Ely Springs Dolomite, is 1,440 feet thick except in the southeast end of the area where it is 870 feet thick. Cherty dark dolomite in the lower part of the Hidden Valley contains Silurian (possibly Llandovery, clearly Wenlock, and probably Ludlow) fossils; dolomite in a somewhat argillaceous and silty uppermost part contains Lower Devonian (upper Emsian) fossils. The Lost Burro Formation, 2,640 feet thick, has Middle Devonian (Givetian) fossils stratigraphically high in the lower part of the formation, which consists of dolomite above the basal Lippincott Member. It has Upper Devonian (Frasnian) fossils midway in the upper part, which consists predominantly of limestone. The Tin Mountain Limestone, 315 feet thick, contains abundant Lower Mississippian (Kinderhookian and Osagean) fossils. The Perdido Formation, which is incomplete and no more than 500 feet thick under unconformable Cenozoic continental rocks, consists mostly of limestone, chert, and siltstone. Fossils, which are scarce, include Upper Mississippian (Meramecian) microfossils 205 feet above the base of the Perdido.

McAllister, James Franklin

1974-01-01

164

Pulmonary paragonimiasis in Southeast Asians living in the central San Joaquin Valley.  

PubMed

We describe four cases of pulmonary paragonimiasis in Southeast Asians who emigrated to the central San Joaquin Valley of California. Physicians should be alerted to the possibility of this disease in Asian patients with hemoptysis and pulmonary infiltrates. Paragonimiasis can masquerade as pulmonary tuberculosis, especially in patients from areas that are endemic for both the parasite and the tubercle bacillus. The ease and safety with which this infection can be treated, in contrast to tuberculosis, reiterates the importance of diagnosing this lung fluke when it is present. PMID:1574893

Yee, B; Hsu, J I; Favour, C B; Lohne, E

1992-04-01

165

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

166

Spatial and seasonal variability of base flow in the Verde Valley, central Arizona, 2007 and 2011  

USGS Publications Warehouse

Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in cooperation with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai County. These surveys, also known as seepage runs, measured streamflow under base-flow conditions at many locations over a short period of time. Surveys were conducted on a segment of the Verde River that flows through the Verde Valley, between USGS streamflow-gaging stations 09504000 and 09506000, a distance of 51 river miles. Data from the surveys were used to investigate the dominant controls on Verde River base flow, spatial variability in gaining and losing reaches, and the effects that human alterations have on base flow in the surface-water system. The most prominent human alterations in the Verde Valley are dozens of surface-water diversions from streams, including gravity-fed ditch diversions along the Verde River.Base flow that entered the Verde River from the tributary streams of Oak Creek, Beaver Creek, and West Clear Creek was found to be a major source of base flow in the Verde River. Groundwater discharge directly into the Verde River near these three confluences also was an important contributor of base flow to the Verde River, particularly near the confluence with Beaver Creek. An examination of individual reaches of the Verde River in the Verde Valley found three reaches (largely unaffected by ditch diversions) exhibiting a similar pattern: a small net groundwater discharge in February 2011 (12 cubic feet per second or less) and a small net streamflow loss in June 2007 (11 cubic feet per second or less). Two reaches heavily affected by ditch diversions were difficult to interpret because of the large number of confounding human factors. Possible lower and upper bounds of net groundwater flux were calculated for all reaches, including those heavily affected by ditches.

Garner, Bradley D.; Bills, Donald J.

2012-01-01

167

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

168

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

169

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

170

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

171

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 (2000–2005 and 2005–2010) 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

172

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 California’s 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 (1×1 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

173

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 winter–spring 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

174

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

175

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

176

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

USGS Publications Warehouse

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.

2002-01-01

177

Weichselian Glaciation History in the 'dry Valleys' of East-Central Southern Norway  

NASA Astrophysics Data System (ADS)

East-central southern Norway is situated within the zone of inferred cold-based (low-erosive) ice-sheets during the Late Weichselian maximum in central Scandinavia. The region has high bedrock coverage of Quaternary deposits, while morphological features are mainly glaciofluvial deltas, kame terraces, shorelines, marginal moraines and various indicators of ice-marginal meltwater drainage. In the studied area, former meltwater flow patterns at high altitudes indicate drainage from east, south and west towards the `dry valleys' of Dorålen, Haverdalen, Grimsdalen and upper Folldal north of the Rondane mountains, and then further northwards across the main watershed to Trondelag. At present, the region is among the driest in Scandinavia with most of the precipitation related to south/south-easterly winds. With a suggested ice divide south of Rondane during the build-up of continental ice sheets in central Scandinavia, the `rainshadow' may have been even more pronounced during glaciations. Hence, the area north of Rondane is suggested to be a key area for studying glacier inception and wastage of Weichselian ice sheets in central Scandinavia. Based on detailed field investigations, both stratigraphical settings and landforms have been dated by use of Optically Stimulated Luminescence (OSL) dating. The results indicate that no period during the Weichselian obtained a large enough lowering of the regional glacier equilibrium-line altitude (ELA) to produce glacier ice at the terrain surface in the valleys north of Rondane. All glaciers that entered this area were produced elsewhere. Three main glacier events have been recorded: the largest occurred about 110-90 kyr ago during the early Weichselian, the next largest took place during early parts of the Middle Weichselian about 70-60 kyr ago, and the third largest occurred during the Late Weichselian maximum c. 20 kyr ago. Based on OSL-dated sections, long periods in between the major glacier advances were dominated by ice-dammed lakes in the upper valley of Folldal and its tributaries. Periglacial features like fossil rock glaciers and ice-wedge casts are related to several of the periods with glacier advances and/or periods with ice-dammed lakes.

Dahl, S.; Lie, O.; Linge, H.; Pytte, A. B.; Murray, A.; Tveranger, J.; Nesje, A.

2004-12-01

178

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

179

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

180

Using remote sensing and GIS techniques to estimate discharge and recharge fluxes for the Death Valley regional groundwater flow system, USA  

Microsoft Academic Search

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 évapotranspiration and infiltration

FRANK A. D'AGNESE; CLAUDIA C. FAUNT; A. KEITH TURNER

1996-01-01

181

Assessment of Climate Change Impacts on Agricultural Water Demands and Crop Yields in California's Central Valley  

NASA Astrophysics Data System (ADS)

Long term planning for the management of California's water resources requires assessment of the effects of future climate changes on both water supply and demand. Considerable progress has been made on the evaluation of the effects of future climate changes on water supplies but less information is available with regard to water demands. Uncertainty in future climate projections increases the difficulty of assessing climate impacts and evaluating long range adaptation strategies. Compounding the uncertainty in the future climate projections is the fact that most readily available downscaled climate projections lack sufficient meteorological information to compute evapotranspiration (ET) by the widely accepted ASCE Penman-Monteith (PM) method. This study addresses potential changes in future Central Valley water demands and crop yields by examining the effects of climate change on soil evaporation, plant transpiration, growth and yield for major types of crops grown in the Central Valley of California. Five representative climate scenarios based on 112 bias corrected spatially downscaled CMIP 3 GCM climate simulations were developed using the hybrid delta ensemble method to span a wide range future climate uncertainty. Analysis of historical California Irrigation Management Information System meteorological data was combined with several meteorological estimation methods to compute future solar radiation, wind speed and dew point temperatures corresponding to the GCM projected temperatures and precipitation. Future atmospheric CO2 concentrations corresponding to the 5 representative climate projections were developed based on weighting IPCC SRES emissions scenarios. The Land, Atmosphere, and Water Simulator (LAWS) model was used to compute ET and yield changes in the early, middle and late 21st century for 24 representative agricultural crops grown in the Sacramento, San Joaquin and Tulare Lake basins. Study results indicate that changes in ET and yield vary between crops due to plant specific sensitivities to temperature, solar radiation and the vapor pressure deficits. Shifts in the growth period to earlier in the year, shortened growth period for annual crops as well as extended fall growth can also exert important influences. Projected increases in CO2 concentrations in the late 21st century exert very significant influences on ET and yield for many crops. To characterize potential impacts and the range of uncertainty, changes in total agricultural water demands and yields were computed assuming that current crop types and acreages in 21 Central Valley regional planning areas remained constant throughout the 21st century for each of the 5 representative future climate scenarios.

Tansey, M. K.; Flores-Lopez, F.; Young, C. A.; Huntington, J. L.

2012-12-01

182

A plan to study the aquifer system of the Central Valley of California  

USGS Publications Warehouse

Unconsolidated Quaternary alluvial deposits comprise a large complex aquifer system in the Central Valley of California. Millions of acre-feet of water is pumped from the system annually to support a large and expanding agribusiness industry. Since the 1950's, water levels have been steadily declining in many areas of the valley and concern has been expressed about the ability of the entire ground-water system to support agribusiness at current levels, not to mention its ability to function at projected expansion levels. At current levels of ground-water use, an estimated 1.5 to 2 million acre-feet is withdrawn from storage each year; that is, 1.5 to 2 million acre-feet of water is pumped annually in excess of annual replenishment. The U.S. Geological Survey has initiated a 4-year study to develop geologic, hydrologic, and hydraulic information and to establish a valleywide ground-water data base that will be used to build computer models of the ground-water flow system. Subsequently, these models may be used to evaluate the system response to various ground-water management alternatives. This report describes current problems, objectives of the study, and outlines the general work to be accomplished in the study area. A bibliography of about 600 references is included. (Kosco-USGS)

Bertoldi, Gilbert L.

1979-01-01

183

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

184

Depth to water, 1991, in the Rathdrum Prairie, Idaho; Spokane River valley, Washington; Moscow-Lewiston-Grangeville area, Idaho; and selected intermontane valleys, east-central Idaho  

USGS Publications Warehouse

This map report illustrates digitally generated depth-to-water zones for the Rathdrum Prairie in Idaho; part of the Spokane River Valley in eastern Washington; and the intermontane valleys of the upper Big Wood, Big Lost, Pahsimeroi, Little Lost, and Lemhi Rivers and Birch Creek in Idaho. Depth to water is 400 to 500 feet below land surface in the northern part of Rathdrum Prairie, 100 to 200 feet below land surface at the Idaho-Washington State line, and 0 to 250 feet below land surface in the Spokane area. Depth to water in the intermontane valleys in east-central Idaho is least (usually less than 50 feet) near streams and increases toward valley margins where mountain-front alluvial fans have formed. Depths to water shown in the Moscow-Lewiston-Grangeville area in Idaho are limited to point data at individual wells because most of the water levels measured were not representative of levels in the uppermost aquifer but of levels in deeper aquifers.

Berenbrock, Charles E.; Bassick, M. D.; Rogers, T. L.; Garcia, S. P.

1995-01-01

185

Variability of the Rh system in a central Pyrenean population (Aran Valley).  

PubMed

This work describes the results of a survey on the Rhesus system carried out in the autochthonous population of Aran Valley, a small and rather isolated region on the Northern side of the Central Pyrenees. Also, a comparison is made with other geographically and historically related populations in order to discuss the data in terms of the historical origin of this population. The data obtained shows a good agreement between observed and expected values in Hardy-Weinberg equilibrium. The Aranese population also reveals some peculiarities concerning some haplotypes. The comparison with European and non European Mediterranean populations shows a clear genetic distance from Basque populations, and a relative proximity with presumably Celtic ones. PMID:1299320

Nogues, R M; Aluja, M P; Malgosa, A; Mas, J

1992-01-01

186

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

187

Human Effects on the Hydrologic System of the Verde Valley, Central Arizona, 1910-2005 and 2005-2110, Using a Regional Groundwater Flow Model.  

National Technical Information Service (NTIS)

Water budgets were developed for the Verde Valley of central Arizona in order to evaluate the degree to which human stresses have affected the hydrologic system and might affect it in the future. The Verde Valley is a portion of central Arizona wherein co...

B. D. Garner B. T. Forbes F. D. Tillman

2010-01-01

188

MODELING THE CENTRAL VALLEY: Investigating the Effects of Irrigation on a Semi-Arid Hydrologic Cycle  

NASA Astrophysics Data System (ADS)

Growing populations and increased aridity in the Central Valley of California, USA has led to a renewed interest regarding the effects of population and anthropogenic irrigation on the region's hydrologic cycle. This model deviates from previous studies in that it utilizes a fully integrated hydrologic model to incorporate surface and subsurface systems on a finely discretized grid and includes an explicit treatment of the mountain systems. A model of the Southern portion of the Central Valley of California was undertaken using ParFlow, an integrated hydrologic model that includes surface, groundwater, land-surface vegetation and snow processes, coupled with the Common Land Model (a land-surface model). The goal of this study was to develop a model that incorporated complex subsurface hydrogeology as well as a complex surface discretization and to complete a comparison study on the effects irrigation on the land-energy and hydrology balances. The resulting model was composed of a matrix of approximately 60,000 sq. km (269 by 219 km) at a 1km resolution run over a period of 4 total model years using parallel processing. This study incorporated irrigation during the summer months (April through September) and no irrigation during wet months (October through March). This study highlights some of the potential impacts that anthropogenic irrigation has on this region including temperature, evapotranspiration and water flow as well techniques for subsurface discretizations (through geological simplifications) and land use variability via the incorporation of both general regional land use modeling as well as detailed county land use maps. The model domain is pictured here shown with a general schematic of flow within the ParFlow system.

Wolfenden, S. A.; Maxwell, R. M.; Lopez, S. R.

2012-12-01

189

Climate Variability and Water-Regulation Effects on Surface Water and Groundwater Interactions in California's Central Valley  

NASA Astrophysics Data System (ADS)

California's Central Valley is one of the most important agricultural areas in the world and is highly dependent on the availability and management of surface water and groundwater. As such, it is a valuable large-scale system for investigating the interaction of climate variability and water-resource management on surface-water and groundwater interactions. In the Central Valley, multiple tools are available to allow scientists to understand these interactions. However, the full effect of human activities on the interactions occurring along the Aquifer-Soil-Plant-Atmosphere continuum remains uncertain. Two models were linked to investigate how non-regulated (natural conditions) and regulated (releases from dams) surface-water inflows from the surrounding contributing drainage areas to the alluvial plains of the Central Valley affects the valley's surface-water supply and groundwater pumpage under different climate conditions. The Variable Infiltration Capacity (VIC) macroscale (surface) hydrologic model was used to estimate the non-regulated streamflow. The U.S. Geological Survey's recently developed Central Valley Hydrologic Model (CVHM) was used to route both the regulated and non-regulated streamflow to the Central Valley and simulate the resulting hydrologic system. The CVHM was developed using MODFLOW's Farm Process (MF-FMP) in order to simulate agricultural water demand, surface-water deliveries, groundwater pumpage, and return flows in 21 water-balance subregions. As such, the CVHM simulates conjunctive use of water, providing a broad perspective on changes in the water systems of the Valley. Inflows from the contributing mountain watersheds are simulated in CVHM using the streamflow-routing package for the 1961-2003 time period. In order to analyze the affect of climate variability, dry and wet years were identified from below the 10th and above the 90th percentiles, respectively, in a multi-decadal time series (1961-2003) of surface-water inflows. The simulated recharge and groundwater pumping rates under four sets of conditions (dry unregulated, wet unregulated, dry regulated, and wet regulated) showed that the southern basins are more sensitive to water regulation than the northern basins. Additional results illustrate spatial differences in crop irrigation requirements during wet and dry years, which also were examined to enhance our understanding of the surface-water/groundwater interactions and their links with climate and resource management in the drainages contributing inflows to the Central Valley.

Munoz-Arriola, F.; Dettinger, M. D.; Hanson, R. T.; Faunt, C.; Cayan, D. R.

2011-12-01

190

Alkaline Basalts of The Quaternary Buffalo Valley Volcanic Field, NW Fish Creek Mountains, North-central Nevada, Great Basin  

Microsoft Academic Search

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,

B. Cousens; C. D. Henry

2008-01-01

191

Very Fine and Ultrafine Metals and Ischemic Heart Disease in the California Central Valley 2: 1974–1991  

Microsoft Academic Search

The southern part of Central Valley of California in winter has long had high PM10 mass, which until about 1990 included sulfate, vanadium, and nickel from the burning of crude oil used to generate steam to enhance heavy petroleum recovery. In roughly 1990, natural gas became the major energy source used for steam generation. In 1989–1991, data were collected throughout

Thomas A. Cahill; David E. Barnes; Earl Withycombe; Mitchell Watnik

2011-01-01

192

Holocene geomorphological processes and soil development as indicator for environmental change around Karakorum, Upper Orkhon Valley (Central Mongolia)  

Microsoft Academic Search

Mantles of silt- and sand-size particles, paleosols and fluvial deposits preserve valuable information on Holocene environmental change. These archives were used to reconstruct the landscape history in the upper Orkhon Valley close to the former capitals of the Uighurs (Kharbalgasin Tuur) and the Mongolian Empire (Karakorum) near the recent town of Kharkhorin, Central Mongolia. A holistic approach involving the use

Frank Lehmkuhl; Alexandra Hilgers; Susanne Fries; Daniela Hülle; Frank Schlütz; Lyudmila Shumilovskikh; Thomas Felauer; Jens Protze

2011-01-01

193

Temperature effects on juvenile anadromous salmonids in California’s central valley: what don’t we know?  

Microsoft Academic Search

The anadromous Chinook salmon (Oncorhynchus tshawytscha) (4 runs) and steelhead (rainbow trout, O. mykiss), are both native to California’s Sacramento-San Joaquin River (SSJR) system, whose watershed encompasses the central valley of California. The SSJR system holds the southernmost extant Chinook salmon populations in the Eastern Pacific Ocean, whereas coastal anadromous steelhead populations are found at more southerly latitudes. Populations of

Christopher A. Myrick; Joseph J. Cech

2004-01-01

194

The NRG1 exon 11 missense variant is not associated with autism in the Central Valley of Costa Rica  

Microsoft Academic Search

BACKGROUND: We are conducting a genetic study of autism in the isolated population of the Central Valley of Costa Rica (CVCR). A novel Neuregulin 1 (NRG1) missense variant (exon 11 G>T) was recently associated with psychosis and schizophrenia (SCZ) in the same population isolate. METHODS: We genotyped the NRG1 exon 11 missense variant in 146 cases with autism, or autism

Lynne A McInnes; Leonid Ouchanov; Alisa Nakamine; Patricia Jimenez; Marcela Esquivel; Marietha Fallas; Silvia Monge; Pamela Bondy; Elina R Manghi

2007-01-01

195

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

edited by Belcher, Wayne R.

2004-01-01

196

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

Edited by: Belcher, Wayne R.; Sweetkind, Donald S.

2010-01-01

197

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.

Edited by Miller, David M.; Valin, Zenon C.

2007-01-01

198

Paleoseismology of a possible fault scarp in Wenas Valley, central Washington  

USGS Publications Warehouse

In October 2009, two trenches excavated across an 11-kilometer-long scarp at Wenas Valley in central Washington exposed evidence for late Quaternary deformation. Lidar imagery of the Wenas Valley illuminated the west-northwest-trending, 2- to 8-meter-high scarp as it bisected alluvial fans developed at the mouths of canyons along the south side of Umtanum Ridge. The alignment of the scarp and aeromagnetic lineaments suggested that the scarp may be a product of and controlled by the same tectonic structure that produced the magnetic lineaments. Several large landslides mapped in the area demonstrated the potential for large mass-wasting events in the area. In order to test whether the scarp was the result of an earthquake-generated surface rupture or a landslide, trenches were excavated at Hessler Flats and McCabe Place. The profiles of bedrock and soil stratigraphy that underlie the scarp in each trench were photographed, mapped, and described, and a sequence of depositional and deformational events established for each trench. The McCabe Place trench exposed a sequence of volcaniclastic deposits overlain by soils and alluvial deposits separated by three unconformities. Six normal faults and two possible reverse faults deformed the exposed strata. Crosscutting relations indicated that up to five earthquakes occurred on a blind reverse fault, and a microprobe analysis of lapilli suggested that the earliest faulting occurred after 47,000 years before present. The Hessler Flat trench exposure revealed weathered bedrock that abuts loess and colluvium deposits and is overlain by soil, an upper sequence of loess, and colluvium. The latter two units bury a distinctive paloesol.

Sherrod, Brian L.; Barnett, Elizabeth A.; Knepprath, Nichole; Foit, Franklin F., Jr.

2013-01-01

199

Natural Protection Against Groundwater Pollution by Nitrates in the Central Valley of Chile\\/Protection Naturelle Contre la Pollution des Eaux Souterraines par les Nitrates Dans la Vallée Centrale du Chili  

Microsoft Academic Search

The Central Valley of Chile is a zone of intensive agricultural activity. Historically, in this zone, large amounts of fertilizers have been applied and low technological level irrigation methods have been used. Contrary to what might be expected, the existing aquifers in the Central Valley do not contain significant nitrate that could be associated with agricultural activity. This situation leads

Jose Luis Arumi; Ricardo Oyarzún; Marco Sandoval

2005-01-01

200

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

201

Trace Element Geochemistry of the Dolomite Member of the Neoproterozoic Ibex Formation, Death Valley National Park, CA  

NASA Astrophysics Data System (ADS)

This work examines the major and trace element geochemistry of the pink, laminated Dolomite Member of the Neoprotoerozic Ibex Formation, sampled at high resolution in the Ibex Hills of Death Valley, California. The Dolomite Member of the Ibex Formation directly overlies a basal conglomerate which has lead Corsetti and Kaufman (2005) to speculate that the juxtaposition of these units represents a diamictite - cap carbonate pair. Cap carbonates are inferred to represent deposition under high alkalinity conditions in the shallow ocean at the termination of low latitude glaciation. Increased alkalinity may be driven by the post glacial overturn of anoxic water masses. Here we infer paleoredox conditions during the deposition of the Dolomite Member of the Ibex Formation using trace metal enrichments. The Dolomite Member shows enrichments of Ni, Mo, Fe, Cu, V, Co, and Ba near the base of the unit, and also has a weak overall enrichment in Mn. The enrichment of these metals suggests a period of anoxia during the initial deposition of the Dolomite, and may signal the introduction of basin brines to the shallow ocean during marine transgression. These data are consistent with patterns observed in other cap carbonates worldwide, and support the speculation that the Dolomite Member is a cap carbonate. Alternatively, trace metal enrichments may reflect diagenetic alteration.

Meyer, E. E.; Lanids, J. D.; Quicksall, A. N.; Ddamba, I.

2012-12-01

202

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

203

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

204

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

205

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

206

Deaths of Mexican and Central American children along the US border: the Pima County Arizona experience.  

PubMed

Using data obtained through the Arizona Child Fatality Review Program, we reviewed deaths of all children (birth-17 years) who were Mexican or Central American residents and who died in Pima County, Arizona during the years 1995-2004. They accounted for 5% of all pediatric deaths in the county. Causes of death were motor vehicle collision (32%), environmental exposure (17%), prematurity (11%), other trauma (11%) and other medical conditions (28%). Fifty-three percent of these children were in the US seeking medical care; 36% were undocumented migrants. Significant trends over the 10 years were toward fewer children seeking medical care and more children dying while border crossing. Border health and economic disparities affected overall child mortality in this US county, but current prevention efforts are unlikely to affect this population group. PMID:17514425

Bowen, Kathryn A; Marshall, William N

2008-02-01

207

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] Róheim, 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

208

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

209

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

210

Rock avalanche deposits in Alai Valley, Central Asia: misinterpretation of glacial record  

NASA Astrophysics Data System (ADS)

The reconstruction of Quaternary glaciations has been restricted by conventional approaches with resulting contradictions in interpretation of the regional glacial record, that recently have been subjected to critical re-evaluation. Along with uncertainties in dating techniques and their applicability to particular landforms (Kirkbride and Winkler, 2012), it has recently been demonstrated that the presence of rock avalanche debris in a landform can be unequivocally detected; this allows for the first time definitive identification of and distinction between glacial moraines and landslide deposits. It also identifies moraines that have formed due to rock avalanche deposition on glaciers, possibly with no associated climatic signal (Reznichenko et al., 2012). Confusion between landslide deposits and moraines is evident for ranges in Central Asia (e.g., Hewitt, 1999) where the least-studied glacial record is selectively correlated with established glacial chronologies in Alpine ranges, which in turn masks the actual glacial extent and their responses to climate change, tectonics and landsliding activity. We describe examples in the glaciated Alai Valley, large intermountain depression between the Zaalay Range of the Northern Pamir and the Alay Range of the Southern Tien-Shan, showing that some large Quaternary deposits classically interpreted as moraines are of rock avalanche origin. Sediment from these deposits has been tested for the presence of agglomerates that are only produced under high stress conditions during rock avalanche motion, and are absent from glacial sediments (Reznichenko et al., 2012). This reveals that morphologically-similar deposits have radically different geneses: rock avalanche origin for a deposit in the Komansu river catchment and glacial origin for deposits in the Ashiktash and Kyzylart catchments. The enormous Komansu rock avalanche deposit, probably triggered by a rupture of the Main Pamir thrust, currently covers about 100 km2 with a minimum estimated volume more than 1 x 109 m3. Another smaller rock avalanche deposit rests on the Lenin Glacial sediment in the neighbour Ashiktash river catchment, which was previously suggested to originate from Mt. Lenin (7134 m). The revised origin of these deposits highlights the role of rock avalanches in glacial activity and in the resulting glacial record in this valley and other actively tectonic areas of Central Asia. Although further investigation is required to detail the geneses, magnitudes and ages for these and other landforms in the valley, this study contributes explicit evidence for contamination of palaeoclimate proxies with data from non-climatic events, and reinforces the urgent need for revised interpretation of the glacial chronologies. Hewitt, K., 1999. Quaternary moraines vs. catastrophic rock avalanches in the Karakoram Himalaya, Northern Pakistan. Quaternary Research, v. 51, p. 220-237. Kirkbride, M.P., and Winkler, S., 2012. Correlation of Late Quaternary moraines: impact of climate variability, glacier response, and chronological resolution: Quaternary Science Reviews, v. 46, p. 1-29. Reznichenko, N.V., Davies, T.R.H., Shulmeister, J. and Larsen S.H, 2012. A new technique for identifying rock-avalanche-sourced sediment in moraines and some paleoclimatic implications. Geology, v. 40, p. 319-322.

Reznichenko, Natalya; Davies, Tim; Robinson, Tom; De Pascale, Gregory

2013-04-01

211

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

PubMed

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 (69-82%), 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. PMID:24779475

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

2014-05-20

212

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

213

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 (69–82%), 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

214

Geochemistry of natural gas manifestions from the Upper Tiber Valley (central Italy)  

USGS Publications Warehouse

Six natural gas manifestions from the upper Tiber Valley at Caprese Michelangela and Pieve S. Stefano (Arezzo) and at Umbertide (Pertugia) localities have been analysed for major, minor, trace gas compositions, as well as for ??13C in CO2 and CH4, ??15N in N2 and 3He/4He isotopic ratios. All gas emissions are CO2-rich (???94%), with N2 contents of 4-5%. Those from Caprese and Pieve S. Stefano have very peculiar compsitions when compared to other gases from northern-central Apennines. Apart from CO2, these gases show relatively high contents of He (with crustal isotopic ratios) and medium to high temperature-related gases such as CO, H2 and C6H6. Although located quite far from the geothermal areas in Tuscany, the application of several gas geothermetric techniques suggest for these gases deep equilibrium tempratures of about 300??C. Moreover, the ??13C in CO2 and CH4 (~.4.0% and -38.0%, respectively) and the ??13N values in N2 (+0.064 to +0.84%) would seem to imply a multiple deep source for these gases.

Vaselli, O.; Tassi, F.; Minissale, A.; Capaccioni, B.; Macro, G.; Evans, W. C.

1997-01-01

215

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

216

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

217

Long-term response of groundwater nitrate concentrations to management regulations in Nebraska's central Platte valley.  

PubMed

The impact of 16 years (1988-2003) of management practices on high groundwater nitrate concentrations in Nebraska's central Platte River valley was assessed in a 58,812-ha (145,215-ac) groundwater quality management area intensively cropped to irrigated corn (Zea mays L.). Crop production and groundwater nitrate data were obtained from approximately 23,800 producer reports. The terrace, comprising approximately 56% of the study area, is much more intensively cropped to irrigated corn than the bottomland. From 1987 to 2003, average groundwater nitrate concentrations in the primary aquifer beneath the bottomland remained static at approximately 8 mg N/l. During the same period, average groundwater nitrate concentrations in the primary aquifer beneath the terrace decreased from 26.4 to 22.0 mg N/l at a slow, but significant (p < 0.0001), rate of 0.26 mg N/l/year. Approximately 20% of the decrease in nitrate concentrations can be attributed to increases in the amount of N removed from fields as a consequence of small annual increases in yield. During the study, producers converted approximately 15% of the approximately 28,300 furrow-irrigated terrace hectares (approximately 69,800 ac) to sprinkler irrigation. The conversion is associated with about an additional 50% of the decline in the nitrate concentration, and demonstrates the importance of both improved water and N management. Average N fertilizer application rates on the terrace were essentially unchanged during the study. The data indicate that groundwater nitrate concentrations have responded to improved management practices instituted by the Central Platte Natural Resources District. PMID:20191240

Exner, Mary E; Perea-Estrada, Hugo; Spalding, Roy F

2010-01-01

218

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

219

Hydrology of Alkali Creek and Castle Valley Ridge coal-lease tracts, central Utah, and potential effects of coal mining  

USGS Publications Warehouse

The Alkali Creek coal-lease tract includes about 2,150 acres in the Book Cliffs coal field in central Utah, and the Castle Valley Ridge coal-lease tract includes about 3,360 acres in the Wasatch Plateau coal field, also in central Utah. Both the Alkali Creek and Castle Valley Ridge coal-lease tracts are near areas where coal is currently (1987) mined by underground methods from the Cretaceous Blackhawk Formation. The Alkali Creek and Castle Valley Ridge areas have intermittent streams in which flow after snowmelt runoff is locally sustained into midsummer by springflow. The only perennial stream is South Fork Corner Canyon Creek in the Castle Valley Ridge area. Peak flow in both areas generally is from snowmelt runoff; however, peak flow from thunderstorm runoff in the Alkali Creek area can exceed that from snowmelt runoff. Estimated annual source-area sediment yield was 0.5 acre-ft/sq mi in the Alkali Creek lease tract and it was 0.3 acre-ft/sq mi in the Castle Valley Ridge lease tract. Groundwater in the Alkali Creek area occurs in perched aquifers in the Flagstaff Limestone and in other formations above the coal-bearing Blackhawk Formation. The principal source of recharge to the aquifers is snowmelt on outcrops. Faults may be major conduits and control the movement of groundwater. Groundwater discharges at formation contacts, between zones of differing permeability within a formation, near faults and into mines. Water sampled from 13 springs in the Alkali Creek area contained dissolved solids at concentrations ranging from 273 to 5,210 mg/L. Water sampled from 17 springs in the Castle Valley Ridge area contained dissolved solids at concentrations ranging from 208 to 579 mg/L. The composition of water from a recently abandoned part of an active mine the Wasatch Plateau closely resembles that of water discharging from a nearby mine that has been abandoned for more than 30 years. Mining of the Alkali Creek and Castle Valley Ridge coal-lease tracts likely will result in decreased pH and increased concentration of dissolved solids of the water that enters the mines. Even after mining, the water, especially in the Castle Valley Ridge area, may still meet Utah 's drinking water standards. (Lantz-PTT)

Seiler, R. L.; Baskin, R. L.

1988-01-01

220

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

221

Regional simulations to quantify land use change and irrigation impacts on hydroclimate in the California Central Valley  

Microsoft Academic Search

In this study, the influence of land use change and irrigation in the California Central Valley is quantified using the Pennsylvania\\u000a State University\\/National Center for Atmospheric Research fifth generation Mesoscale Model (MM5) coupled with the Community\\u000a Land Model version 3 (CLM3). The simulations were forced with modern-day and presettlement land use types at 30-km spatial\\u000a resolution for the period 1

Jiming Jin; Norman L. Miller

2011-01-01

222

Bedrock channel geometry along an orographic rainfall gradient in the upper Marsyandi River valley in central Nepal  

Microsoft Academic Search

Pronounced rainfall gradients combined with spatially uniform exhumation of rocks at Quaternary timescales and uniform rock strength make the upper Marsyandi River valley in central Nepal a useful natural laboratory in which to explore variations in bedrock channel width. We focus on small catchments (0.6–12.4 km2) along a more than tenfold gradient in monsoon rainfall. Rainfall data are gathered from

William H. Craddock; Douglas W. Burbank; Bodo Bookhagen; Emmanuel J. Gabet

2007-01-01

223

Bedrock channel geometry along an orographic rainfall gradient in the upper Marsyandi River valley in central Nepal  

Microsoft Academic Search

Pronounced rainfall gradients combined with spatially uniform exhumation of rocks at Quaternary timescales and uniform rock strength make the upper Marsyandi River valley in central Nepal a useful natural laboratory in which to explore variations in bedrock channel width. We focus on small catchments (0.6-12.4 km2) along a more than tenfold gradient in monsoon rainfall. Rainfall data are gathered from

William H. Craddock; Douglas W. Burbank; Bodo Bookhagen; Emmanuel J. Gabet

2007-01-01

224

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

225

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

226

Magnetic Orbital and Reversal Stratigraphy of the Johnnie Formation, Death Valley region, with implications for the Shuram Carbon Isotope Excursion  

NASA Astrophysics Data System (ADS)

This study demonstrates a ~720 kyr depositional period for 33 meters of dolomites from the Johnnie Formation at the Winters Pass Hills locality in Death Valley, CA. These dolomites have been shown to record the Shuram carbon isotope anomaly (Corsetti and Kaufman, 2003). We provide a new record of the anomaly that demonstrates the presence of the Shuram excursion from its nadir of ?13C= -12 ‰ to a recovered value of -8 ‰. By comparison to a full stratigraphic reconstruction of the Shuram Excursion by Verdel et al. (2011) the measured section from this study represents roughly 1/10 of the Shuram excursion, suggesting a 7.2 myr duration for the complete excursion, significantly shorter than the 50 myr estimate of Le Guerroué et al. (2006). The orbitally-forced stratigraphy used to make this measurement was obtained by performing multi-taper method spectral analysis on data series of magnetic susceptibility and a magnetically measured goethite to hematite ratio. Cyclic variations in magnetic susceptibility with wavelengths of 18.6 m and 5.4 m are observed in the spectrum above the 95% significance level with respect to the robust red noise and are interpreted to represent varying concentrations of paramagnetic clay particles forced by climate controlled weathering and transport of sediment to the ancient Laurentian passive margin. 0.63m and 0.71 m wavelength cycles with spectral peaks above the 95% significance level are also observed. A magnetic reversal stratigraphy developed by thermal demagnetization of oriented samples demonstrates three polarity intervals in the dolomites of the Winters Pass Hills, constraining the depositional period of the dolomites to <1 myr (estimate of magnetic reversal frequency for the Meso-NeoProterozoic based on Pavlov and Gallet, 2010). This suggests that cycles with wavelengths of 18.6m, 5.4m, and 0.71m represent long eccentricity, short eccentricity, and precession, respectively. The ratio of goethite to hematite also varies cyclically with wavelengths of 18.6m, 5.8m, and 0.63m. The goethite is most likely the product of present day weathering and may represent variations in depositional Fe-rich clay particles. These results replicate results obtained by Kodama and Hillhouse (2011) in the Nopah Range of Death Valley, approximately 40 km to the north. The Nopah Range rocks were deposited in a more distal sedimentary environment in the same depositional basin. The agreement between the two studies suggests a basin wide response to climatic forcing of depositional processes observable by the rock magnetic cyclostratigraphy. Assuming the period of Earth's long eccentricity has not varied significantly since the Ediacaran period (Laskar et al., 2011; Berger and Loutre, 1994) and that the magnetostratigraphy constrains the 33 m section to <1 myr, depositional cycles of 18.6m represent ~400 kyr, 5.4 m cycles represent ~116 kyr, and 0.71m cycles represent ~15 kyr.

Minguez, D. A.; Kodama, K. P.; Hillhouse, J. W.

2012-12-01

227

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

228

EFFECTIVE MODEL CALIBRATION OF THE GEOLOGICALLY COMPLEX DEATH VALLEY REGIONAL GROUND-WATER FLOW SYSTEM, NEVADA AND CALIFORNIA  

SciTech Connect

A numerical ground-water flow model is being constructed for the Death Valley regional ground-water system, an area that encompasses approximately 80,000 km{sup 2} in southern Nevada and southeastern California. Effective construction and calibration of the regional-scale steady-state flow model, developed using MODFLOW-2000, is dependent upon integration of hydrogeologic data and parameter-estimation techniques. A three-dimensional hydrogeologic-framework model of the region was initially constructed to provide a conceptual model of the geometry, composition, and hydraulic properties of the materials that control the regional ground-water flow system. This framework was resampled at the scale of the flow model to define the hydrogeologic units present in each of the 15 flow-model layers. In addition, there are non-traditional types of geologic data in the hydrogeologic-framework model that are used during flow-model calibration. For each hydrogeologic unit, the spatial distribution of geologic features important to the hydrologic system is defined. The volumetric cells can be populated by various hydrogeologic data such as the hydrogeologic unit, lithology, hydraulic conductivity, faulting, tectonic features, stratigraphic or lithologic facies, porosity, and derivative data calculated from these attributes. The approach for using this arsenal of geologic data is dependent on utilizing parameter-estimation techniques available within MODFLOW-2000. The principle of parsimony is used throughout the flow-modeling process so that a simple conceptual model is methodically made more complex. Initially, the most basic conceptual model that could reasonably define the flow system was constructed and geologic units were grouped into four major hydrogeologic units. Only major geologic structures were included; there was little structural or stratigraphic differentiation, and a minimum number of parameters were used. As the calibration process progresses, additional complexity is added to the flow model. Evaluation of the flow model is based on analysis of several MODFLOW-2000 functions such as composite scaled sensitivity, weighted and unweighted hydraulic-head and flow residuals, comparison of parameter estimates with reasonable values based on previous studies, and parameter correlations. These functions provide information on whether the available hydraulic-head and ground-water discharge data are likely to be sufficient to estimate parameter values and to subdivide parameters into more detailed units. If sufficient data are available then a parameter can be subdivided into several parameters that represent specific distinguishing hydrogeologic features. For example, in the Death Valley region the lower carbonate aquifer is widely distributed and although regionally uniform, areas with unique hydrologic characteristics exist. Although the lower carbonate aquifer was initially considered one hydrogeologic unit with one set of hydrologic properties, it has been progressively subdivided into different structural and stratigraphic regions with unique hydrologic properties. The best flow model consists of the fewest number of parameters that can adequately describe the flow system and meet the modeling objectives.

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

2000-10-19

229

Relation of deformation and multiple intrusion in the Death Valley extended region, California, with implications for magma entrapment mechanism  

NASA Astrophysics Data System (ADS)

The crystalline core of the Black Mountains crustal section, Death Valley, California, exposes a tremendous volume of Miocene plutonic rock intruded at a depth of 10-13 km. Few plutons were intruded above ˜10 km prior to unroofing by tectonic denudation. In the eastern part of the core, a brittle detachment fault separates predominantly Miocene hanging wall strata from the midcrustal, Miocene (11.6 and ˜8.7 Ma), plutonic complex and Early Proterozoic basement. In the west, mylonitic lineations and foliations, locally well-developed within the 11.6 Ma intermediate-mafic Willow Spring pluton, are cut by dikes which emanate from an ˜8.7 Ma silicic plutonic complex. The younger silicic complex throughout the crystalline core exhibits few ductile deformational structures. Published thermal and barometric studies from both plutonic bodies indicate similar midcrustal (10-13 km) emplacement depths at ambient temperatures just above 300°C. The significant difference in densities of these magmas argues against a density control for magma entrapment. Also, the country rock above and below the plutonic complex contains no apparent differences (from field observations) that would suggest a change in density. The depth of entrapment corresponds well with the expected depth for the crustal strength maximum determined from laboratory experiments. The similar emplacement depths but contrasting styles of deformation of the two plutonic bodies further suggests that entrapment may have been controlled by a high-strength barrier represented by the brittle-ductile transition. Late hypabyssal intrusions and associated volcanism are linked to diachronous rapid unroofing of the range block; all show a northwest progression paralleling the regional extension direction. Thus when migration of magma through the high-strength barrier did occur, it was apparently related to increased strain rates which allowed magma ascent by fracture exploitation. Rheological stratification of the crust may have played an important, if not major, role in trapping magmas in the middle crust in this area.

Holm, Daniel K.

1995-06-01

230

Modeling The Evolution Of A Regional Aquifer System With The California Central Valley Groundwater-Surface Water Simulation Model (C2VSIM)  

Microsoft Academic Search

The finite element application IWFM has been used to develop an integrated groundwater-surface water model for California's Central Valley, an area of ~50,000 km2, to simulate the evolution of the groundwater flow system and historical groundwater-surface water interactions on a monthly time step from October 1921 to September 2003. The Central Valley's hydrologic system changed significantly during this period. Prior

C. F. Brush; E. C. Dogrul; T. N. Kadir; M. R. Moncrief; S. Shultz; M. Tonkin; D. Wendell

2006-01-01

231

Neotectonics of the Marikina Valley fault system (MVFS) and tectonic framework of structures in northern and central Luzon, Philippines  

NASA Astrophysics Data System (ADS)

Recognition of neotectonic features along the Marikina Valley fault system (MVFS) in central Luzon, Philippines indicates a dominantly dextral strike-slip motion during its most recent activity believed to be Late Pleistocene to Holocene in age. Variations in the ratios of vertical to horizontal displacements for the segments imply a dominantly dextral motion of the West Marikina Valley fault (WMVF) and oblique dextral motion for the East Marikina Valley fault (EMVF). The displacement data further suggest that rupturing along the EMVF involved multiple segments and occurred separately from the events along the WMVF segments. Estimated earthquake magnitudes for the WMVF and EMVF based on single-event offsets fall within the range M 7.3-7.7. The vertical slip component in the northern part of the Marikina Valley is associated with the development of a basin between the EMVF and WMVF while the large vertical component in the southernmost segment of the EMVF (Talim) is attributed to volcanism-related extension. Lateral advection of the block bounded by the MVFS and the Philippine fault zone (PFZ), rather than pure shear resulting from an assumed east-west compression, best explains the observed kinematics of the MVFS. This is the result of compression during the westward drift of the Philippine Sea Plate and northern Luzon and occurs through slip along the WMVF and EMVF at rates of 5-7 mm/yr.

Rimando, Rolly E.; Knuepfer, Peter L. K.

2006-03-01

232

Rainwater harvesting for small-scale irrigation of maize in the Central Rift Valley, Ethiopia  

NASA Astrophysics Data System (ADS)

In the Central Rift Valley of Ethiopia, small scale farmers mostly rely on rainfall for crop production. The erratic nature of rainfall causes frequent crop failures and makes the region structurally dependent on food aid. Rainwater Harvesting (RWH) is a technique to collect and store runoff that could provide water for livestock, domestic use or small scale irrigation. Usually, such irrigation is promoted for high value crops, but in the light of regional food security it may become interesting to invest in irrigation of maize. In this research, two cemented RWH cisterns were investigated to determine their economic and social potential for supplemental irrigation of maize using drip irrigation. For this, data from test fields with irrigated maize and monitoring of water levels of the cisterns were used, as well as a survey under 30 farmers living close to the experimental site. The results show that catchment size and management should be in balance with the designed RWH system, to prevent too little runoff or flooding. An analysis with Cropwat 8.0 was used to investigate the possibility of irrigating maize with the observed amounts of water in the RWH cisterns. This would suffice for 0.3-0.8 ha of maize. For a RWH cistern with a drip irrigation system to be economically viable, the production on this acreage should become 3-4 ton/ha; 2.5 times higher than the current yield. But the biggest challenge would be to change the perception of respondents, who don't find it logical to spend precious water on a common crop like maize. Therefore, if the Ethiopian government considers the irrigation of maize to be important for regional food security, it is recommended to either subsidize the construction of RWH cisterns or provide credit on favourable terms.

Keesstra, Saskia; Hartog, Maaike; Muluneh, Alemayehu; Stroosnijder, Leo

2013-04-01

233

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

234

Biological assessment of urban and agricultural streams in the California Central Valley.  

PubMed

This project was designed to establish baseline aquatic biological community structure and physical habitat conditions in select wadeable streams within the California Central Valley. A secondary objective was to evaluate possible water quality differences between site types and seasons. Two agricultural and two urban streams were monitored in spring and fall for two consecutive years beginning in the fall of 2002. Bioassessment sampling was conducted according to modified US EPA methods. The study included physical habitat assessment, water and sediment chemical analysis and characterization of the benthic macroinvertebrate community at each site. Water samples were analyzed for selected organophosphate insecticides, pyrethroid insecticides and herbicides, while sediment samples were analyzed for pyrethroids only. All sites had substantial physical habitat and water quality impairments, and the absence of pollution intolerant macroinvertebrates and dominance of pollution tolerant macroinvertebrates were indications of biological impairment. Due to the limited amount of water quality and pesticide data collected, it was not possible to definitively demonstrate any cause and effect relationships between BMI community structure and water quality or pesticide concentrations. Though most physical habitat parameters were similar and EPA physical habitat scores revealed on no significant differences between urban and agricultural sites (P=0.290), a significant difference was seen in substrate embeddedness (P=0.020). Dominant taxon found at all sites were chironomids, amphipods, and oligochaetes. Benthic macroinvertebrate metrics were significantly different between both types of sites (P=0.001) and seasons (P=0.014). Chironomidae taxon and those of the functional feeding group scrapers were greater at urban sites, while those of the functional feeding group filterers were greater at agricultural sites. In addition, the metric groups Chironomidae, filterers, and predators were found in greater numbers in the spring than the fall. PMID:17072545

Bacey, Juanita; Spurlock, Frank

2007-07-01

235

Soil chemical changes under irrigated mango production in the Central São Francisco River Valley, Brazil.  

PubMed

Irrigated areas in Brazil's Central São 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 São Francisco River. PMID:12931897

Heck, R J; Tiessen, H; Salcedo, I H; Santos, M C

2003-01-01

236

Land-Use and Land-Cover Dynamics in the Central Rift Valley of Ethiopia  

NASA Astrophysics Data System (ADS)

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.

Garedew, Efrem; Sandewall, Mats; Söderberg, Ulf; Campbell, Bruce M.

2009-10-01

237

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

238

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

239

Early Oligocene partial melting in the Main Central Thrust Zone (Arun valley, eastern Nepal Himalaya)  

NASA Astrophysics Data System (ADS)

The Main Central Thrust Zone (MCTZ) is a key tectonic feature in the architecture of the Himalayan chain. In the Arun valley of the eastern Nepal Himalaya, the MCTZ is a strongly deformed package of amphibolite- to granulite-facies metapelitic schist and granitic orthogneiss. This package is tectonically interposed between the underlying, low-grade, Lesser Himalaya sequences and the overlying, high-grade and locally anatectic, Higher Himalayan Crystallines (HHC). The MCTZ is characterized by a well documented inverted metamorphism from the Grt-Bt zone, across the Ky-in, St-in and -out, Kfs-in, Ms-out and Sil-in isograds. Partial melting with local occurrence of migmatitic segregations has been rarely reported from the highest structural levels of the MCTZ. While it is widely accepted that thrusting along the MCT occurred during the Miocene, geochronological data constraining the timing of crustal anatexis in the upper portion of the MCTZ are still lacking. In order to understand the link between partial melting in the MCTZ and the Miocene activation of the MCT, we present the P- T-time evolution of a kyanite-bearing anatectic gneiss occurring at the highest structural levels of the MCTZ, along the Arun-Makalu transect (eastern Nepal). Microstructural observations combined with P- T pseudosection analysis show that dehydration partial melting occurred in the kyanite-field. After reaching peak conditions at about 820 °C, 13 kbar, the studied sample experienced decompression accompanied by cooling down to 805 °C, 10 kbar, which caused in situ melt crystallization. SHRIMP monazite and zircon geochronology provides evidence that the anatexis affecting the upper portion of the MCTZ occurred during Early Oligocene (˜ 31 Ma). These results demonstrate that in the upper MCTZ, at least in the eastern Himalaya, crustal anatexis was earlier than, and not a consequence of, decompression linked to exhumation along the MCT.

Groppo, Chiara; Rubatto, Daniela; Rolfo, Franco; Lombardo, Bruno

2010-08-01

240

[Floristic composition and structure of a premontane moist forest in Central Valley of Costa Rica].  

PubMed

The floristic composition and structure of a premontane moist forest remnant were studied in the El Rodeo Protected Zone, Central Valley of Costa Rica. Three one-hectare plots were established in the non-disturbed forest, and all trees with a diameter at breast height (dbh) of 10 cm or greater were marked, measured and identified. The plots were located within a radius of 500 m from each other. A total of 106 tree species were recorded in the three plots. Average values: species richness 69.6 species ha-1, abundance 509 individuals ha-1, basal area 36.35 m2 ha-1. Total diversity was 3.54 (Shannon Index, H'), and the species similarity among the plots ranged between S = 0.68 and 0.70 (Sørensen Similarity Index). Most tree species are represented by few individuals (five or less). There is a lack of emergent trees and arborescent palms in the forest canopy. According to the Familial Importance Value, Moraceae, followed by Fabaceae, Lauraceae, and Sapotaceae, largely dominates this forest. Pseudolmedia oxyphillaria (Moraceae) is the dominant species (Importance Value Index), accounting for 25% of all the marked trees in the plots, followed by Clarisia racemosa (Moraceae), Heisteria concinna (Olacaceae), and Brosimum alicastrum (Moraceae). The size class distributions were similar among plots, and in general followed the expected J-inverted shape. Differences in tree abundance, floristic composition, and spatial distribution of some species among the plots suggest heterogeneity of this ecosystem's arborescent vegetation. Moreover, it is an important natural reservoir for the conservation of rare and endangered tree species in a national level. Using these results as a baseline, this study should start a long term monitoring of the structure and composition of this very reduced and fragmented ecosystem. PMID:11795150

Cascante, A; Estrada, A

2001-03-01

241

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 Niño 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

242

Role of cell death in the formation of sexual dimorphism in the Drosophila central nervous system.  

PubMed

Currently, sex differences in behavior are believed to result from sexually dimorphic neural circuits in the central nervous system (CNS). Drosophila melanogaster is a common model organism for studying the relationship between brain structure, behavior, and genes. Recent studies of sex-specific reproductive behaviors in D. melanogaster have addressed the contribution of sexual differences in the CNS to the control of sex-specific behaviors and the development of sexual dimorphism. For example, sexually dimorphic regions of the CNS are involved in the initiation of male courtship behavior, the generation of the courtship song, and the induction of male-specific muscles in D. melanogaster. In this review, I discuss recent findings about the contribution of cell death to the formation of sexually dimorphic neural circuitry and the regulation of sex-specific cell death by two sex determination factors, Fruitless and Doublesex, in Drosophila. PMID:21338349

Kimura, Ken-Ichi

2011-02-01

243

Differential hypermethylation of death-associated protein kinase promoter in central neurocytoma and oligodendroglioma.  

PubMed

Background. Central neurocytoma and oligodendroglioma are rare tumors of the central nervous system. However, diagnosis between these two types of tumors is challenging due to their many cytological and histological similarities. Death-associated protein kinase (DAPK) is a calcium/calmodulin-regulated serine/threonine protein kinase involved in many apoptosis pathways, and repressed expression of DAPK by promoter hypermethylation has been found in a variety of human cancers. The purpose of this study was to assess DAPK protein expression and promoter hypermethylation in central neurocytoma and oligodendroglioma. Method. Central neurocytoma and oligodendroglioma samples were obtained from age- and sex-matched patients. DAPK protein expression was performed using immunohistochemical assays in formalin-fixed, paraffin-embedded sections. DAPK promoter hypermethylation was carried out using bisulfite-modified genomic DNA in methylation-specific PCR followed by separation in agarose gels. Findings. A statistically significant difference (P = 0.021) in DAPK promoter hypermethylation between central neurocytoma (76.9%) and oligodendroglioma (20%) was observed. High levels of DAPK protein expression were generally found in oligodendroglioma (90%), compared with 38.5% in central neurocytoma (P = 0.054; not statistically significant). There was an inverse correlation between DAPK protein expression and DAPK promoter hypermethylation in the cohort of 23 patients (P = 0.002). Conclusions. The results show that DAPK promoter hypermethylation and repressed expression of DAPK protein were more common in central neurocytoma than in oligodendroglioma. Thus, DAPK promoter hypermethylation could be useful for differential diagnosis between these two types of tumors, whereas DAPK protein expression might be less predictive. The role of DAPK promoter hypermethylation in the pathogenesis of central neurocytoma warrants further study. PMID:24877104

Chung, Chia-Li; Tsai, Hung Pei; Tsai, Cheng-Yu; Chen, Wan-Tzu; Lieu, Ann-Shung; Wang, Chih-Jen; Sheehan, Jason; Chai, Chee-Yin; Kwan, Aij-Lie

2014-01-01

244

Differential Hypermethylation of Death-Associated Protein Kinase Promoter in Central Neurocytoma and Oligodendroglioma  

PubMed Central

Background. Central neurocytoma and oligodendroglioma are rare tumors of the central nervous system. However, diagnosis between these two types of tumors is challenging due to their many cytological and histological similarities. Death-associated protein kinase (DAPK) is a calcium/calmodulin-regulated serine/threonine protein kinase involved in many apoptosis pathways, and repressed expression of DAPK by promoter hypermethylation has been found in a variety of human cancers. The purpose of this study was to assess DAPK protein expression and promoter hypermethylation in central neurocytoma and oligodendroglioma. Method. Central neurocytoma and oligodendroglioma samples were obtained from age- and sex-matched patients. DAPK protein expression was performed using immunohistochemical assays in formalin-fixed, paraffin-embedded sections. DAPK promoter hypermethylation was carried out using bisulfite-modified genomic DNA in methylation-specific PCR followed by separation in agarose gels. Findings. A statistically significant difference (P = 0.021) in DAPK promoter hypermethylation between central neurocytoma (76.9%) and oligodendroglioma (20%) was observed. High levels of DAPK protein expression were generally found in oligodendroglioma (90%), compared with 38.5% in central neurocytoma (P = 0.054; not statistically significant). There was an inverse correlation between DAPK protein expression and DAPK promoter hypermethylation in the cohort of 23 patients (P = 0.002). Conclusions. The results show that DAPK promoter hypermethylation and repressed expression of DAPK protein were more common in central neurocytoma than in oligodendroglioma. Thus, DAPK promoter hypermethylation could be useful for differential diagnosis between these two types of tumors, whereas DAPK protein expression might be less predictive. The role of DAPK promoter hypermethylation in the pathogenesis of central neurocytoma warrants further study.

Chung, Chia-Li; Tsai, Hung Pei; Tsai, Cheng-Yu; Chen, Wan-Tzu; Lieu, Ann-Shung; Wang, Chih-Jen; Sheehan, Jason; Chai, Chee-Yin; Kwan, Aij-Lie

2014-01-01

245

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

246

Simulation of net infiltration and potential recharge using a distributed-parameter watershed model of the Death Valley region, Nevada and California  

USGS Publications Warehouse

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 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. To estimate the magnitude and distribution of potential recharge in response to variable climate and spatially varying drainage basin characteristics, the INFILv3 model uses a daily water-balance model of the root zone with a primarily deterministic representation of the processes controlling net infiltration and potential recharge. The daily water balance includes precipitation (as either rain or snow), snow accumulation, sublimation, snowmelt, infiltration into the root zone, evapotranspiration, drainage, water content change throughout the root-zone profile (represented as a 6-layered system), runoff (defined as excess rainfall and snowmelt) and surface water run-on (defined as runoff that is routed downstream), and net infiltration (simulated as drainage from the bottom root-zone layer). Potential evapotranspiration is simulated using an hourly solar radiation model to simulate daily net radiation, and daily evapotranspiration is simulated as an empirical function of root zone water content and potential evapotranspiration. The model uses daily climate records of precipitation and air temperature from a regionally distributed network of 132 climate stations and a spatially distributed representation of drainage basin characteristics defined by topography, geology, soils, and vegetation to simulate daily net infiltration at all locations, including stream channels with intermittent streamflow in response to runoff from rain and snowmelt. The temporal distribution of daily, monthly, and annual net infiltration can be used to evaluate the potential effect of future climatic conditions on potential recharge. The INFILv3 model inputs representing drainage basin characteristics were developed using a geographic information system (GIS) to define a set of spatially distributed input parameters uniquely assigned to each grid cell of the INFILv3 model grid. The model grid, which was defined by a digital elevation model (DEM) of the Death Valley region, consists of 1,252,418 model grid cells with a uniform grid cell dimension of 278.5 meters in the north-south and east-west directions. The elevation values from the DEM were used with monthly regression models developed from the daily climate data to estimate the spatial distribution of daily precipitation and air temperature. The elevation values were also used to simulate atmosp

Hevesi, Joseph A.; Flint, Alan L.; Flint, Lorraine E.

2003-01-01

247

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

248

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

249

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

250

Analysis of the quality of image data acquired by the LANDSAT-4 thematic mapper and multispectral scanners. [Central Valley, California  

NASA Technical Reports Server (NTRS)

Image products and numeric data were extracted from both TM and MSS data in an effort to evaluate the quality of these data for interpreting major agricultural resources and conditions in California's Central Valley. The utility of TM data appears excellent for meeting most of the inventory objectives of the agricultural resource specialist. These data should be extremely valuable for crop type and area proportion estimation, for updating agricultural land use survey maps at 1:24,000-scale and smaller, for field boundary definition, and for determining the size and location of individual farmsteads.

Colwell, R. N. (principal investigator)

1983-01-01

251

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

252

I. Detailed records of geomagnetic field behavior from Death Valley and Hawaii. II. An age constraint on Gulf of California rifting from Santa Rosalia, Baja California  

NASA Astrophysics Data System (ADS)

Paleomagnetic studies were performed on sedimentary rocks exposed in the Confidence Hills of southern Death Valley. These rocks contain two records of the upper Olduvai geomagnetic polarity reversal (1.79 Ma) which agree despite differences of lithology, depositional environment, and structural tilting. The records show evidence for an aborted reversal during the transition from normal to reversed polarity. Transitional virtual geomagnetic poles (VGP's) lie in longitudinal bands approx. 90sp° from the sampling site longitude, vastly different from VGP's produced elsewhere for this reversal but consistent with site-dependent trends of VGP paths observed in global data compilations. Studies of the anisotropy of anhysteritic remanence conclude that inclination shallowing in sediments during low geomagnetic field intensities is a possible cause for the site dependence of VGP paths. Another detailed paleomagnetic record from the Confidence Hills shows that the Reunion normal-polarity subchron was a single event of approx. 20 kyr duration (2.15-2.13 Ma). The presence of a lithofacies containing disruptive evaporite crystals creates two small gaps in the record just prior to the normal-polarity Reunion interval. A paleomagnetic study was performed on the 1-km Hawaii Scientific Drilling Project core. This core sampled over 200 lava flows erupted from Mauna Loa and Mauna Kea volcanos in the past 400 kyr. The results of this study show that secular variation at Hawaii is consistent with that elsewhere on Earth for the past 400 kyr. In addition, the data show evidence for a persistent axial quadrupole in the time-averaged field and the first records of the Blake and Pringle Falls or Jamaica geomagnetic field excurions in the central Pacific. Paleomagnetic and geochronologic studies performed on marine sedimentary rocks from Santa Rosalia, Baja California Sur, Mexico resulted in an estimated age of 7.1 ± 0.05 Ma for the base of the Boleo Formation, the earliest marine rocks there. This provides a new age constraint on Gulf of California rifting and may help refine models of North America-Pacific plate interactions during 12-3.5 Ma.

Holt, John William

253

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; Montañez, Isabel P.; Martin, Lauren G.; Wardlaw, Bruce R.; Sandberg, Charles A.; Wan, Elmira; Olson, Holly A.; Priest, Susan S.

2014-01-01

254

Gravity Data from Dry Lake and Delamar Valleys, east-central Nevada  

USGS Publications Warehouse

Cenozoic basins in eastern Nevada and western Utah constitute major ground-water recharge areas in the eastern part of the Great Basin, and our continuing studies are intended to characterize the geologic framework of the region. Prior to these investigations, regional gravity coverage was variable over the region, adequate in some areas and very sparse in others. The current study in Nevada provides additional high-resolution gravity along transects in Dry Lake and Delamar Valleys to supplement data we established previously in Cave and Muleshoe Valleys. We combine all previously available gravity data and calculate an up-to-date isostatic residual gravity map of the study area. Major density contrasts are identified, indicating zones where Cenozoic tectonic activity could have been accommodated. A gravity inversion method is used to calculate depths to pre-Cenozoic basement rock and to estimate maximum alluvial/volcanic fill in the valleys. Average depths of basin fill in the deeper parts of Cave, Muleshoe, Dry Lake, and Delamar Valleys are approximately 4 km, 2 km, 5 km, and 3 km, respectively.

Mankinen, Edward A.; Chuchel, Bruce A.; Moring, Barry C.

2008-01-01

255

Hydrogeologic Framework of Antelope Valley and Bedell Flat, Washoe County, West-Central Nevada.  

National Technical Information Service (NTIS)

The purpose of this report is to describe the hydrogeologic framework of the Antelope Valley and Bedell Flat Hydrographic Areas. This framework is defined by: (1) the rocks and deposits that transmit ground water or impede its movement, and (2) the combin...

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

2001-01-01

256

Tectonic implications of basaltic volcanism within the central Owens Valley, California  

Microsoft Academic Search

Basaltic volcanism occurs at four locations in the Owens Valley. We examine the Big Pine field south of Independence, CA and the Darwin field situated 45 miles to the southeast on the Darwin Plateau. Big Pine basalts were extruded between 1.2 Ma and 25 ka. They range in composition from ne normative alkali basalt to Q normative tholeiitic basalt. Basalts

David R. Jessey; Matthew W. Lusk; Ashley Varnell-Lusk

2009-01-01

257

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 km²; the Kurshab River basin, 2010 km2; the Akbura River basin, 2260 km²) 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

258

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 1913–1998. 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

259

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

260

Assessment of regional change in nitrate concentrations in groundwater in the Central Valley, California, USA, 1950s-2000s  

USGS Publications Warehouse

A regional assessment of multi-decadal changes in nitrate concentrations was done using historical data and a spatially stratified non-biased approach. Data were stratified into physiographic subregions on the basis of geomorphology and soils data to represent zones of historical recharge and discharge patterns in the basin. Data were also stratified by depth to represent a shallow zone generally representing domestic drinking-water supplies and a deep zone generally representing public drinking-water supplies. These stratifications were designed to characterize the regional extent of groundwater with common redox and age characteristics, two factors expected to influence changes in nitrate concentrations over time. Overall, increasing trends in nitrate concentrations and the proportion of nitrate concentrations above 5 mg/L were observed in the east fans subregion of the Central Valley. Whereas the west fans subregion has elevated nitrate concentrations, temporal trends were not detected, likely due to the heterogeneous nature of the water quality in this area and geologic sources of nitrate, combined with sparse and uneven data coverage. Generally low nitrate concentrations in the basin subregion are consistent with reduced geochemical conditions resulting from low permeability soils and higher organic content, reflecting the distal portions of alluvial fans and historical groundwater discharge areas. Very small increases in the shallow aquifer in the basin subregion may reflect downgradient movement of high nitrate groundwater from adjacent areas or overlying intensive agricultural inputs. Because of the general lack of regionally extensive long-term monitoring networks, the results from this study highlight the importance of placing studies of trends in water quality into regional context. Earlier work concluded that nitrate concentrations were steadily increasing over time in the eastern San Joaquin Valley, but clearly those trends do not apply to other physiographic subregions within the Central Valley, even where land use and climate are similar.

Burow, Karen R.; Jurgens, Bryant C.; Belitz, Kenneth; Dubrovsky, Neil M.

2013-01-01

261

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; Sánchez-Chinchillas, Argelia; Argote, Rosa Maria

2012-06-01

262

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

263

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

264

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 California’s 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

265

Dynamic Adjustments in Channel Width in Response to a Forced Diversion: Gower Gulch, Death Valley National Park, California  

NASA Astrophysics Data System (ADS)

We study the 1941 diversion of Furnace Creek Wash (drainage area 439 km2) into Gower Gulch (5.8 km2) as an experiment in the transient response of channel geometry to a large change in water and sediment discharge. We measure sequential changes in valley width using a time series of aerial photographs (1948-1995), airborne laser elevation data from 2005, and a field survey. We find that response of the system varies depending on the pre-diversion channel morphology and geology. In two steep knickzone segments, narrowing, knickpoint retreat, and bedrock incision dominates-- a detachment-limited response. In the relatively low-gradient main part of Gower Gulch, fine-grained, soft sedimentary rocks underlie the channel, and widening dominates as the large, coarse post-diversion sediment load covers the channel bed. The response in this section is transport limited, with only modest incision and adjustments in gradient. Two different processes appear to cause the channel to widen. (1) In many reaches, the stream is attacking the valley walls, as evidenced by fresh plucking and scour marks. This probably occurs because the bed in the middle of the channel is alluviated and protected, which minimizes the opportunity for vertical incision. (2) Some reaches have experienced aggradation, which widens the valley by filling it in. This occurs in places where storage space exists (splay deposits in small tributary mouths, fill terraces in the wide valleys at larger tributary mouths) or in reaches upstream of constrictions. Over long periods, the lowering rate of Gower Gulch probably depends on knickpoint retreat, but the present-day response of this non-steady-state system is a hybrid of incision and narrowing in detachment-limited reaches and widening in transport-limited reaches. This system demonstrates the importance of initial conditions and evolving channel geometry in setting the transient response of rivers.

Snyder, N. P.; Kammer, L. L.

2007-12-01

266

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

267

Climate change impact on future water resources availability for a semi-arid area (Ferghana Valley, Central Asia)  

NASA Astrophysics Data System (ADS)

Considering increasing temperatures and glacier recession during the last decades, it is of high interest to study the climate change impact on water resources availability in semi-arid regions of Central Asia. The Ferghana Valley is surrounded by the Tien-Shan and Pamiro-Alay mountain systems that store big amounts of water in snowpacks and glaciers. In the valley the agricultural activity of local people strongly depends on available water from the Syrdarya River. The river is formed by the confluence of the Naryn and Karadarya Rivers, which are mainly fed by the glacier and snow melt from the Akshiirak and Ferghana ridges of the aforementioned mountain systems. The small upper river basins of the valley also contribute with runoff (~34 %) to the Syrdarya River. These small rivers are mainly fed by precipitation and seasonal snow melt. Thus, because of climate change and glacier decline, it is necessary to investigate the comparative contribution of the small catchments versus two big river basins to the Syrdarya River system, as these small upper catchments could become more important for future water consumption. In this study the conceptual hydrological HBV-light model has been calibrated and validated for the period 1980-1985 over 18 upper catchments that feed the Syrdarya River from the surrounding mountain ridges. Dynamically downscaled climate change scenarios were then applied up to the year 2100 for these basins. The scenarios were generated by means of Global Circulation Model (ECHAM5) and Regional Climate Model (REMO) with a baseline period from 1971 till 2000. We will present modelling results of water resources, the contribution of small rivers to the Syrdarya River and to what extent this contribution is likely to change in the future. Moreover, the results of simulated potential runoff will be used to develop future climate change adaptation strategies regarding socio-economic and environmental sustainable water use.

Radchenko, Iuliia; Breuer, Lutz; Mannig, Birgit; Frede, Hans-Georg

2014-05-01

268

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 39°37.5' and 40°00' N and longitude 119°37.5' and 120°00' 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 39°32.30' N, longitude 119°48.70' W, observed gravity value 979674.69 mGal). The value for observed gravity was calculated by multiple ties to the base station RENO (latitude 39°32.30' N, longitude 119°48.70' 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

269

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

270

Chemistry of fog waters in California's Central Valley—Part 3: concentrations and speciation of organic and inorganic nitrogen  

NASA Astrophysics Data System (ADS)

Although organic nitrogen (ON) has been found to be a ubiquitous and significant component in wet and dry deposition, almost nothing is known about its concentration or composition in fog waters. To address this gap, we have investigated the concentration and composition of ON in fog waters collected in Davis, in California's Central Valley. Significant quantities of dissolved organic nitrogen (DON) were found in these samples, with a median concentration of 303 ?M N (range=120-1630 ?M N). DON typically represented approximately 16% of the total dissolved nitrogen (inorganic+organic) in Davis fog waters. The median concentration of nitrogen in free amino acids and alkyl amines was 16 ?M N (range=3.8-120 ?M N), which accounted for 3.4% of the DON in Davis fogs. Thus, although the absolute concentrations of free amino compounds were significant, they were only a minor component of the DON pool. Combined amino nitrogen (e.g., proteins and peptides) was present at higher concentrations and accounted for 6.1-29% (median=16%) of DON. Overall, free and combined amino compounds typically accounted for a median value of 22% of DON in the fog waters. The high concentrations of DON found, and the fact that amino and other N-containing organic compounds can serve as nitrogen sources for microorganisms and plants, indicate that atmospheric ON compounds likely play an important role in nitrogen cycling in the Central Valley. In addition, due to the basicity of some N functional groups, ON compounds likely contribute to the previously observed acid buffering capacity of Central Valley fog waters. Finally, a comparison of fog waters with fine particles (PM 2.5) collected from the same site during the same period of time indicated that the median concentrations (mol N m -3-air) of total water-soluble ON, free amino nitrogen and total amino nitrogen were very similar in the fog water and PM 2.5. Given the high water solubility of many organic N compounds, this result suggests that ON might contribute to the hygroscopic properties of atmospheric particles.

Zhang, Qi; Anastasio, Cort

271

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

272

Vivid valleys, pallid peaks? Hypsometric variations and rural-urban 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 3260 m asl 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 rural–urban migration trends and contrary to several results of extra-Andean studies. Consequently, rural–urban 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.

Haller, Andreas

2012-01-01

273

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

274

Starch grain and phytolith evidence for early ninth millennium B.P. maize from the Central Balsas River Valley, Mexico  

PubMed Central

Questions that still surround the origin and early dispersals of maize (Zea mays L.) result in large part from the absence of information on its early history from the Balsas River Valley of tropical southwestern Mexico, where its wild ancestor is native. We report starch grain and phytolith data from the Xihuatoxtla shelter, located in the Central Balsas Valley, that indicate that maize was present by 8,700 calendrical years ago (cal. B.P.). Phytolith data also indicate an early preceramic presence of a domesticated species of squash, possibly Cucurbita argyrosperma. The starch and phytolith data also allow an evaluation of current hypotheses about how early maize was used, and provide evidence as to the tempo and timing of human selection pressure on 2 major domestication genes in Zea and Cucurbita. Our data confirm an early Holocene chronology for maize domestication that has been previously indicated by archaeological and paleoecological phytolith, starch grain, and pollen data from south of Mexico, and reshift the focus back to an origin in the seasonal tropical forest rather than in the semiarid highlands.

Piperno, Dolores R.; Ranere, Anthony J.; Holst, Irene; Iriarte, Jose; Dickau, Ruth

2009-01-01

275

Starch grain and phytolith evidence for early ninth millennium B.P. maize from the Central Balsas River Valley, Mexico.  

PubMed

Questions that still surround the origin and early dispersals of maize (Zea mays L.) result in large part from the absence of information on its early history from the Balsas River Valley of tropical southwestern Mexico, where its wild ancestor is native. We report starch grain and phytolith data from the Xihuatoxtla shelter, located in the Central Balsas Valley, that indicate that maize was present by 8,700 calendrical years ago (cal. B.P.). Phytolith data also indicate an early preceramic presence of a domesticated species of squash, possibly Cucurbita argyrosperma. The starch and phytolith data also allow an evaluation of current hypotheses about how early maize was used, and provide evidence as to the tempo and timing of human selection pressure on 2 major domestication genes in Zea and Cucurbita. Our data confirm an early Holocene chronology for maize domestication that has been previously indicated by archaeological and paleoecological phytolith, starch grain, and pollen data from south of Mexico, and reshift the focus back to an origin in the seasonal tropical forest rather than in the semiarid highlands. PMID:19307570

Piperno, Dolores R; Ranere, Anthony J; Holst, Irene; Iriarte, Jose; Dickau, Ruth

2009-03-31

276

The environmental costs of mountaintop mining valley fill operations for aquatic ecosystems of the Central Appalachians.  

PubMed

Southern Appalachian forests are recognized as a biodiversity hot spot of global significance, particularly for endemic aquatic salamanders and mussels. The dominant driver of land-cover and land-use change in this region is surface mining, with an ever-increasing proportion occurring as mountaintop mining with valley fill operations (MTVF). In MTVF, seams of coal are exposed using explosives, and the resulting noncoal overburden is pushed into adjacent valleys to facilitate coal extraction. To date, MTVF throughout the Appalachians have converted 1.1 million hectares of forest to surface mines and buried more than 2,000 km of stream channel beneath mining overburden. The impacts of these lost forests and buried streams are propagated throughout the river networks of the region as the resulting sediment and chemical pollutants are transmitted downstream. There is, to date, no evidence to suggest that the extensive chemical and hydrologic alterations of streams by MTVF can be offset or reversed by currently required reclamation and mitigation practices. PMID:21449964

Bernhardt, Emily S; Palmer, Margaret A

2011-03-01

277

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 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 20-30 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; Rötter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-11-01

278

Younger Dryas Cladocera assemblages from two valley mires in central Poland and their potential significance for climate reconstructions  

NASA Astrophysics Data System (ADS)

Two sections of sediment from small oxbow-lake infillings located in different river valleys in central Poland were studied by cladoceran analysis in order to examine the response of aquatic ecosystems to the Younger Dryas. Lithological and geochemical records, as well as chydorid (Chydoridae) ephippia analysis were also used to reconstruct Younger Dryas climate trends. A high concentration of cladocerans, as well as the presence of Cladocera taxa preferring warmer water, was found. It is likely that local processes in the oxbow lakes were important, because the presence of warm-preferring taxa was also related to their habitats and their development. Yet local environmental forces, such as the influence of the rivers, habitat modification, macrophyte abundance, and eutrophication, were not only major factors to affect the Cladocera diversity in the Younger Dryas. The observation of changes in the composition and concentration of Cladocera in oxbow-lake infillings indicates that most of the changes occurred in response to climate changes.

Paw?owski, Dominik

2012-12-01

279

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

280

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

281

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

282

Dissolved Pesticide and Organic Carbon Concentrations Detected in Surface Waters, Northern Central Valley, California, 2001-2002  

USGS Publications Warehouse

Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central Valley of California. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of California. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central Valley of California and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of California Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, California. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon analyzer.

Orlando, James L.; Jacobson, Lisa A.; Kuivila, Kathryn M.

2004-01-01

283

Soilscape analysis at different scales using pattern indices in the Jarama-Henares interfluve and Henares River valley, Central Spain  

NASA Astrophysics Data System (ADS)

The Jarama-Henares interfluve is located south of the Ayllon range, one of the easternmost ranges of the "Sistema Central" mountains in central Spain. The Henares river valley is asymmetric, with 20 topographic benches along its right bank and a series of glacis-terraces on its left bank. We investigated the soil-geoform units in the Jarama-Henares interfluve and the Henares river valley using several indices to quantify and understand the evolution of soil and landscape patterns of the area during the Plio-Quaternary. Features such fragmentation, dominance, geopedologic unit diversity, relative spatial diversity, size and shape, neighbourhood and interaction were analysed in geopedologic maps prepared at two scales (1:18,000 and 1:50,000) using ancillary data, aerial photographs and field observations. Likewise, the taxonomic pedorichness and pedodiversity were assessed on plot maps at 1:100 scale representing three fluvial terrace areas of different age. Soil diversity analysis was carried out at the subgroup level of the USDA Soil Taxonomy using (1) the number of individuals included in a given pedotaxum, and (2) the areal proportion occupied by each soil taxum in a given map unit. One of the main findings was that the values of the indices were higher and the number of indices required to describe appropriately the soilscape patterns was smaller at the local than at the regional scale, the relative spatial diversity being one of the most useful indices. At the plot scale, taxonomic pedorichness and pedodiversity of soil subgroups increased from low/young to high/old terraces. Thus, pattern indices can be used to characterise soilscape evolution aspects such as diversification due to the behaviour of the depositional system or to relief dissection.

Saldaña, A.; Ibáñez, J. J.; Zinck, J. A.

2011-12-01

284

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

285

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

286

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 ˜3640 m asl and ˜3740 m asl respectively. The Stage-II moraines have been optically dated between 25 ± 2 ka and 22 ± 1 ka implying that glacier expanded during the global Last Glacial Maximum (LGM). This is contrary to the suggestion that during Last Glacial maximum (LGM) glaciation was limited in extent due to weak Indian Summer Monsoon (ISM) in the monsoon dominated regions of the Himalaya. We ascribe the LGM glaciations to a combination of the lowered temperature and enhanced mid-latitude westerlies. Following the LGM glaciation, Goriganga valley experienced two major pulses of deglaciation. The older event is dated between 16 and 12 ka and is coeval with the initiation of the ISM whereas the younger events (10-8 ka) represent the early to mid-Holocene strengthened ISM. The Stage-III and IV glaciations which terminated proximal to the modern glacier are speculated to occur during the mid-Holocene and Little Ice Age (LIA) respectively.

Nawaz Ali, S.; Biswas, R. H.; Shukla, A. D.; Juyal, N.

2013-08-01

287

Postglacial fluvial response and landform development in the upper Muskegon River valley in North-Central Lower Michigan, U.S.A  

Microsoft Academic Search

This study focuses on the upper part of the Muskegon River system in north-central Lower Michigan and is the first to reconstruct the post-glacial history of fluvial landform development in the core of North America's Great Lakes region. Results indicate that the upper Muskegon River valley contains four alluvial terraces and numerous paleomeanders. Radiocarbon dating of peats within these old

Alan F. Arbogast; Juleigh R. Bookout; Bradley R. Schrotenboer; Amy Lansdale; Ginny L. Rust; Victorino A. Bato

2008-01-01

288

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

289

Constraints from fission track analysis on the evolution of the Rio Tinguiririca valley area in the Main Cordillera of the Andes, Central Chile  

Microsoft Academic Search

In the Rio Tinguiririca valley in the Main Cordillera of the Andes of central Chile, 35° south, parts of a stratigraphic section ranging from the late Jurassic to the Quaternary are exposed. Fission track analysis was carried out on samples from all the stratigraphic units exposed in the area in order to gain information on the low-grade metamorphic history of

K. Waite; S. Schmidt

2005-01-01

290

Copper Canyon track locality (Pliocene) conservation strategies, Death Valley National Park, USA (Gestion et mise en valeur du site à pistes pliocènes 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

291

Digital Elevation Model (DEM) file of topographic elevations for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1-degree Digital Elevation Model data files.  

National Technical Information Service (NTIS)

Elevation data have been compiled into a digital data base for an approx. 100,000-sq km area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35 deg N, long 115 deg W, and lat 38 deg N, long 118 d...

A. K. Turner F. A. D'Agnese C. C. Faunt

1996-01-01

292

Amelioration of central cardiovascular regulatory dysfunction by tropomyocin receptor kinase B in a mevinphos intoxication model of brain stem death  

PubMed Central

BACKGROUND AND PURPOSE Little information exists on the mechanisms that precipitate brain stem death, the legal definition of death in many developed countries. We investigated the role of tropomyocin receptor kinase B (TrkB) and its downstream signalling pathways in the rostral ventrolateral medulla (RVLM) during experimental brain stem death. EXPERIMENTAL APPROACH An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos bilaterally into the RVLM of Sprague–Dawley rats was used, in conjunction with cardiovascular, pharmacological and biochemical evaluations. KEY RESULTS A significant increase in TrkB protein, phosphorylation of TrkB at Tyr516 (pTrkBY516), Shc at Tyr317 (pShcY317) or ERK at Thr202/Tyr204, or Ras activity in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Microinjection bilaterally into RVLM of a specific TrkB inhibitor, K252a, antagonized those increases. Pretreatment with anti-pShcY317 antiserum, Src homology 3 binding peptide (Grb2/SOS inhibitor), farnesylthioacetic acid (Ras inhibitor), manumycin A (Ras inhibitor) or GW5074 (Raf-1 inhibitor) blunted the preferential augmentation of Ras activity or ERK phosphorylation in RVLM and blocked the up-regulated NOS I/protein kinase G (PKG) signalling, the pro-life cascade that sustains central cardiovascular regulation during experimental brain stem death. CONCLUSIONS AND IMPLICATIONS Activation of TrkB, followed by recruitment of Shc/Grb2/SOS adaptor proteins, leading to activation of Ras/Raf-1/ERK signalling pathway plays a crucial role in ameliorating central cardiovascular regulatory dysfunction via up-regulation of NOS I/PKG signalling cascade in the RVLM in brain stem death. These findings provide novel information for developing therapeutic strategies against this fatal eventuality.

Chan, SHH; Chan, JYH; Hsu, KS; Li, FCH; Sun, EYH; Chen, WL; Chang, AYW

2011-01-01

293

Socioeconomic effects of power marketing alternatives for the Central Valley and Washoe Projects: 2005 regional econmic impact analysis using IMPLAN  

SciTech Connect

The Western Area Power Administration (Western) was founded by the Department of Energy Organization Act of 1977 to market and transmit federal hydroelectric power in 15 western states outside the Pacific Northwest, which is served by the Bonneville Power Administration. Western is divided into four independent Customer Service Regions including the Sierra Nevada Region (Sierra Nevada), the focus of this report. The Central Valley Project (CVP) and the Washoe Project provide the primary power resources marketed by Sierra Nevada. Sierra Nevada also purchases and markets power generated by the Bonneville Power Administration, Pacific Gas and Electric (PG&E), and various power pools. Sierra Nevada currently markets approximately 1,480 megawatts of power to 77 customers in northern and central California. These customers include investor-owned utilities, public utilities, government agencies, military bases, and irrigation districts. Methods and conclusions from an economic analysis are summarized concerning distributional effects of alternative actions that Sierra Nevada could take with it`s new marketing plan.

Anderson, D.M.; Godoy-Kain, P.; Gu, A.Y.; Ulibarri, C.A.

1996-11-01

294

Geohydrology of the central Mesilla Valley, Dona Ana County, New Mexico  

USGS Publications Warehouse

Five large-capacity irrigation wells, with depths ranging from 370 to 686 feet, were drilled by the Elephant Butte Irrigation District between 1973 and 1975, in the Mesilla Valley about 7 miles south of Las Cruces, New Mexico. These were the first deep wells in the area, and their installation provided an opportunity to conduct extensive aquifer tests under relatively undisturbed conditions. The deep irrigation wells are perforated in the Santa Fe Group of Miocene to Pleistocene Age. The Santa Fe Group is composed of interfingering and alternating beds of clay, silt, sand, and small gravel. In the area of these wells, the upper part of the saturated zone contains slightly saline water to a depth of about 100 to 175 feet below the water table, underlain by a freshwater zone extending to depths greater than 1,200 feet. As water is pumped from the freshwater zone, leakage occurs from above and below the perforated interval. At one of the irrigation district wells, slightly saline water moved downward because of a lack of confining layers in the aquifer. At three other wells, the surface casing was not set deep enough and slightly saline water moved into the top of the perforations , downward in the casing, and into the freshwater part of the aquifer. (USGS)

Wilson, Clyde A.; White, Robert R.

1984-01-01

295

Winter raptor use of the Platte and North Platte River Valleys in south central Nebraska  

USGS Publications Warehouse

Winter distribution and abundance of raptors were monitored within the Platte and North Platte river valleys. Data were collected along 265 km of census routes along the Platte and North Platte rivers during the winters of 1978-1979 and 1979-1980. Observations recorded during the second winter involved less observation time and were at somewhat different periods. There were 1574 sightings of 15 species representing 3 raptor families. Number of raptors observed on 54 days from 15 November to 13 February 1978-1979 was 48.3 per 100 km. In 20 days of observation from 5 December to 6 March 1979-1980, 39.7 raptors were observed per 100 km. Small mammal indices were 21 and 12 captures per 1000 trap nights during November 1978 and 1979, respectively. Raptors were sighted most frequently in riverine habitat and least in pasture and tilled fields. American kestrels (Falco sparverius) (11.1 individuals/100 km), red-tailed hawks (Buteo jamaicensis) (9.9), and bald eagles (Haliaeetus leucocephalus) (9.6) were the most frequently sighted raptors. Northern harrier (Circus cyaneus), rough-legged hawk (B. lagopus), and prairie falcon (P. mexicanus) sightings were 3.4, 3.4, and 1.7, respectively. Nine species were seen at a frequency of less than 1.0 individuals/100 km. Improved foraging conditions throughout the region resulted in fewer raptors sighted in 1979-1980.

Lingle, G. R.

1989-01-01

296

New geochronological, paleoclimatological, and archaeological data from the Narmada Valley hominin locality, central India  

Microsoft Academic Search

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

Rajeev Patnaik; Parth R. Chauhan; M. R. Rao; B. A. B. Blackwell; A. R. Skinner; Ashok Sahni; M. S. Chauhan; H. S. Khan

2009-01-01

297

A central role for carbon-overflow pathways in the modulation of bacterial cell death.  

PubMed

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

2014-06-01

298

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.

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

299

Cosmogenic 10Be and 36Cl geochronology of offset alluvial fans along the northern Death Valley fault zone: Implications for transient strain in the eastern California shear zone  

NASA Astrophysics Data System (ADS)

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 the Red Wall Canyon alluvial fan, which exposes clean dextral offsets of seven channels. Analysis of airborne laser swath mapping data indicates ˜297 ± 9 m of right-lateral displacement on the fault system since the late Pleistocene. In situ terrestrial cosmogenic 10Be and 36Cl geochronology was used to date the Red Wall Canyon fan and a second, correlative fan also cut by the fault. Beryllium 10 dates from large cobbles and boulders provide a maximum age of 70 +22/-20 ka for the offset landforms. The minimum age of the alluvial fan deposits based on 36Cl depth profiles is 63 ± 8 ka. Combining the offset measurement with the cosmogenic 10Be date yields a geologic fault slip rate of 4.2 +1.9/-1.1 mm yr-1, whereas the 36Cl data indicate 4.7 +0.9/-0.6 mm yr-1 of slip. Summing these slip rates with known rates on the Owens Valley, Hunter Mountain, and Stateline faults at similar latitudes suggests a total geologic slip rate across the northern ECSZ of ˜8.5 to 10 mm yr-1. This rate is commensurate with the overall geodetic rate and implies that the apparent discrepancy between geologic and geodetic data observed in the Mojave section of the ECSZ does not extend north of the Garlock fault. Although the overall geodetic rates are similar, the best estimates based on geology predict higher strain rates in the eastern part of the ECSZ than to the west, whereas the observed geodetic strain is relatively constant.

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

2007-06-01

300

SEASONAL VARIATION IN PESTICIDE LOADS AND TRENDS IN THE CENTRAL VALLEY, CALIFORNIA: CALCULATED USING TWO PARAMETRIC METHODS  

NASA Astrophysics Data System (ADS)

Mass loading and trends in concentration were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream; and, (2) the Sine Wave model (SineWave), in which first-order Fourier series sine and cosine terms are used to simulate seasonal loading patterns. The models were applied to data for water years 1997 through 2005 provided by the National Water Quality Assessment Program (NAWQA). The pesticides considered in this study were carbaryl, diazinon, metolachlor, and molinate. Data were analyzed for two seasons: precipitation season (October through March), and the irrigation season (April through September). Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. When compared with results from previous studies, both models well estimated seasonal loads and trends in concentrations. It is important to point out that loads estimated by the two models did not differ substantially from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and precipitation. At the same time, trends in pesticide concentrations over time, as estimated by both models, were nearly identical indicating that either model can be used equally for calculating trends in concentrations. However, in watersheds where pesticides are applied in specific patterns— involving multiple applications of various amounts—the SeaWave model might be a better model to use due to its robust capability to describe seasonal variations in pesticide concentrations. As a case study, trends in pesticide concentrations for streams in the Central Valley were estimated using SeaWave. Timing of peak concentrations for individual compounds varied greatly across this geographic gradient because of different application periods and the effects of local rainfall patterns, irrigation, and soil drainage. Pesticides that have been the target of numerous regulatory actions, such as diazinon and chlorpyrifos, tended to have negative trends at most of the sampling locations as agriculturists shifted to the use of alternative pesticides and urban users faced mandatory sales restrictions. In general, herbicides, which have not been the target of regulatory restrictions, generally showed no significant changes in concentrations. However, in a few cases the model indicated increasing trends resulting from land-use changes or decreasing trends due to shifts in herbicide product use (like diazinon) in the watersheds.

Saleh, D.; Domagalski, J. L.; Johnson, H. M.; Lorenz, D. J.

2009-12-01

301

Character and evolution of the ground-water flow system in the central part of the western San Joaquin Valley, California  

USGS Publications Warehouse

The occurrence of selenium in agricultural drain water derived from the western San Joaquin Valley, California, has focused concern on the groundwater flow system of the western valley. Previous work and recently collected texture and water level data were used to evaluate the character and evolution of the regional groundwater flow system in the central part of the western valley, with particular emphasis on the deposits overlying the Corcoran Clay Member of the Tulane Formation. The Corcoran Clay Member, where present, divides the flow system into an upper semiconfined zone and a lower confined zone. Above the Corcoran, three geohydrologic units can be recognized: Coast Range alluvium, Sierran sand, and flood-basin deposits. These units differ in texture, hydrologic properties, and oxidation state. The development of irrigated agriculture in the central part of the western valley has significantly altered the flow system. Percolation of irrigation water past crop roots has caused a rise in the altitude of the water table in mid-fan and distal-fan areas. Pumpage of groundwater from wells has caused a lowering of the water table beneath parts of the fanheads and a lowering of the potentiometric surface of the confined zone over much of the western valley. The combination of percolation and pumpage has resulted in development of a large downward hydraulic head gradient in the semi-confined zone and has created a groundwater divide along the western margin of the valley. Surface water deliveries from the California Aqueduct have allowed a decrease in pumpage and a consequent recovery in hydraulic head throughout the system. (Author 's abstract)

Belitz, K. R.

1988-01-01

302

Crustal imaging using old industry seismic reflection data across the Coast Ranges and the Great Valley in Central Californa, USA  

NASA Astrophysics Data System (ADS)

We make use of the old industry seismic reflection data set SJ-6 in order to image middle and lower crustal structures beneath the California Coast Ranges and the Great Valley in Central California. For this purpose we use advanced imaging techniques in combination with a local 3D tomographic velocity model in order to map the reflectivity structure of the crust in particular across the San Andreas fault zone. The SJ-6 data set is so far the only active seismic data set crossing the San Andreas fault where the transitional fault segment approaches into the locked segment that last ruptured during the 1857 M7.9 Fort Tejon earthquake. This particular region shows major non volcanic tremor activity that is related directly to and at close range to the deep San Andreas fault zone. The SJ-6 data have been recorded along a crooked profile line that changes its predominating orientation from SW-NE to W-E after crossing the San Andreas fault surface trace. For this reason the imaging technique is implemented in 3D in order to account for the true source and receiver locations. We use a Prestack Kirchhoff type migration method called Fresnel Volume migration that spatializes the recorded reflection energy to the vicinity of the actual reflector elements according to the subsurface model. The results are high quality seismic images of improved signal- to noise ratio compared to standard Prestack Kirchhoff migration techniques. In order to extract reflection signals recorded from the deep crust we extend the record length of the data by adding zeros to the original field data and then crosscorrelate the latter with the source sweep signal. Several adjustments are applied to the migration and stacking schemes in order to obtain final 2D depth sections that represent the reflectivity structure directly beneath the crooked acquisition line. The most prominent feature southwest of the San Andreas fault is a bundle of strong northeast dipping reflectors within the lower crust of the Salinian Block. Several northeast dipping coherent reflectors in the middle crust appear directly southwest to the San Andreas fault that disappear when they approach the fault zone. The San Andreas fault can be localized in the image as zone that lacks of strong coherent reflectors in the middle and lower crust. The upper part of the fault zone reveals short truncated reflectors of variable orientations possibly representing fault gouge material. Microseismic events are located within the upper 13 km of that zone and non volcanic tremor locations correlate well with the minor reflective lower part of the fault zone. The most significant feature beneath the eastern segment of line SJ-6 are west dipping reflectors in the middle crust beneath west tilted sedimentary layer sequences of the Great Valley. These structures may represent sequences of ultramafic rocks called Great Valley Ophiolites. Several geophysical investigations along the Great Valley indicate its existance and cause new debates on the pre-Cenozoic evolution of this major plate boundary.

Gutjahr, Stine; Buske, Stefan

2014-05-01

303

Diagenesis of quartz in the Upper Proterozoic Kaimur Sandstones, Son Valley, central India  

NASA Astrophysics Data System (ADS)

The Upper Proterozoic Kaimur Sandstones in central India are quartz-, sublithic- and lithic-arenites cemented by quartz, illite and hematite. Diagenetic quartz occurs in five modes: syntaxial overgrowths, fracture healings, aggregates of small euhedral crystals, quartz resulting from the alteration of detrital silicates and from the recrystallization of quartz. Intergranular pressure dissolution is suggested as the main source of silica with smaller contribution from other sources, such as silica dissolved in meteoric waters, stylolitization, clay-mineral diagenesis, and the alteration of detrital silicates. Studies on the fluid inclusions and oxygen isotopes of diagenetic quartz suggest that meteoric water modified by diagenetic reactions has mediated the quartz cementation.

Morad, S.; Bhattacharyya, Ajit; Al-Aasm, I. S.; Ramseyer, K.

1991-10-01

304

Palaeoenvironmental response to the ˜74 ka Toba ash-fall in the Jurreru and Middle Son valleys in southern and north-central India  

NASA Astrophysics Data System (ADS)

Distal deposits of rhyolitic volcanic ash from the ˜74 ka "supervolcanic" eruption of Toba, in northern Sumatra, are preserved in numerous river valleys across peninsular India. The Toba eruption is hypothesized to have resulted in climate change and the devastation of ecosystems and hominin populations. This study reports the results of the analysis of sediments and stratigraphical sequences from sites in the Jurreru and Middle Son valleys in southern and north-central India. The aim of the study is to determine the extent of palaeoenvironmental change in both valleys as a result of the ash-fall. Inferences based on evidence from the Jurreru valley are more detailed, where pre- and post-Toba palaeoenvironmental changes are divided into seven phases. The results indicate that ash-fall deposits in both valleys underwent several phases of reworking that possibly lasted for several years, indicating that ash was mobile in the landscape for a considerable period of time prior to burial. This could have enhanced and lengthened the detrimental effects of the ash on vegetation and water sources, as well as animal and hominin populations.

Jones, Sacha Claire

2010-03-01

305

Mixed carbonate-siliciclastic infilling of a Neogene carbonate shelf-valley system: Tampa Bay, West-Central Florida  

Microsoft Academic Search

The shelf-valley system underlying Tampa Bay, Florida’s largest estuary, is situated in the middle of the Neogene carbonate Florida Platform. Compared to well-studied fluvially incised coastal plain valley systems, this shelf-valley system is unique in its karstic origin and its alternating carbonate-siliciclastic infill. A complex record of sea-level changes, paleo-fluvial variability and marine processes have controlled the timing and mechanisms

David S. Duncan; Stanley D. Locker; Gregg R. Brooks; Albert C. Hine; Larry J. Doyle

2003-01-01

306

Parkinson's Disease and Residential Exposure to Maneb and Paraquat From Agricultural Applications in the Central Valley of California  

PubMed Central

Evidence from animal and cell models suggests that pesticides cause a neurodegenerative process leading to Parkinson's disease (PD). Human data are insufficient to support this claim for any specific pesticide, largely because of challenges in exposure assessment. The authors developed and validated an exposure assessment tool based on geographic information systems that integrated information from California Pesticide Use Reports and land-use maps to estimate historical exposure to agricultural pesticides in the residential environment. In 1998–2007, the authors enrolled 368 incident PD cases and 341 population controls from the Central Valley of California in a case-control study. They generated estimates for maneb and paraquat exposures incurred between 1974 and 1999. Exposure to both pesticides within 500 m of the home increased PD risk by 75% (95% confidence interval (CI): 1.13, 2.73). Persons aged ?60 years at the time of diagnosis were at much higher risk when exposed to either maneb or paraquat alone (odds ratio?=?2.27, 95% CI: 0.91, 5.70) or to both pesticides in combination (odds ratio?=?4.17, 95% CI: 1.15, 15.16) in 1974–1989. This study provides evidence that exposure to a combination of maneb and paraquat increases PD risk, particularly in younger subjects and/or when exposure occurs at younger ages.

Cockburn, Myles; Bronstein, Jeff; Zhang, Xinbo; Ritz, Beate

2009-01-01

307

Modelling air quality impact of a biomass energy power plant in a mountain valley in Central Italy  

NASA Astrophysics Data System (ADS)

In this study, we investigate the potential impact on local air quality of a biomass power plant, which is planned for installation near L'Aquila, a city of 70,000 people located in a mountain valley in Central Italy. The assessment is carried out by applying a one year simulation with the CALPUFF model, following the recommendations of the U. S. Environmental Protection Agency. Meteorological input is produced with CALMET model, fed with both MM5 meteorological fields at 3 km resolution and wind observations from a surface weather station. We estimate small (<0.5 ?g m-3) annual average increments to SO2, NO2 and PM10 ambient levels over the domain of interest, but significant (up to 50% for NO2) enhancements and several violations (up to 141 for NO2) of hourly limits for human protection within 1.5 km from the source. These results anticipate a larger negative effect on local air quality than those published by the building firm of the plant. We also suggest that a minimum distance of 5 km from the nearest residential area would represent a significant decrease of population exposure.

Curci, Gabriele; Cinque, Giovanni; Tuccella, Paolo; Visconti, Guido; Verdecchia, Marco; Iarlori, Marco; Rizi, Vincenzo

2012-12-01

308

Influence of grazing and available moisture on breeding densities of grassland birds in the central platte river valley, Nebraska  

USGS Publications Warehouse

We investigated the relationship between grassland breeding bird densities and both grazing and available moisture in the central Platte River Valley. Nebraska between 1980 and 1996. We also compared species richness and community similarity of breeding birds in sedge (Carex spp.) meadows and mesic grasslands. Densities of two species had a significant relationship with grazing and six of seven focal species had a significant relationship with available moisture. Bobolink (Dolichonyx oryzivorus) and Brown-headed Cowbird (Molothrus ater) densities were lower in grazed plots compared to ungrazed plots, whereas Red-winged Blackbird (Agelaius phoeniceus) densities were greater in sedge-meadow plots compared to mesic grassland plots. Bobolink, Dickcissel (Spiza americana). and Brown-headed Cowbird were negatively associated with available moisture with breeding densities peaking during the driest conditions. Our results suggest that wet conditions increase species richness for the community through addition of wetland-dependant and wetland-associated birds, but decrease densities of ground-nesting grassland birds in wet-meadow habitats, whereas dry conditions reduce species richness but increase the density of the avian assemblage. We propose that wet-meadow habitats serve as local refugia for grassland-nesting birds during local or regional droughts.

Kim, D. H.; Newton, W. E.; Lingle, G. R.; Chavez-Ramirez, F.

2008-01-01

309

Magnetic Susceptibility and Mineral Zonations Controlled by Provenance in Loess along the Illinois and Central Mississippi River Valleys  

NASA Astrophysics Data System (ADS)

Magnetic susceptibility (MS) patterns have proven useful for regional stratigraphic correlations of zones within thick, oxidized Peoria and Roxana Silts along the Illinois and Central Mississippi River valleys for more than 350 km. Variations in MS of C horizon loess are controlled by silt-sized magnetite content and are interpreted to reflect changes in sediment provenance due to fluctuations of the Superior and Lake Michigan glacier lobes and the diversion of the Mississippi River to its present course. Grain size distributions and scanning electron microscopic observations indicate that stratigraphic changes in MS are not significantly influenced by eolian sorting or diagenetic dissolution, respectively. Three compositional zones (lower, middle, and upper) are delineated within Peoria Silt which usually can be traced in the field by MS, the occurrence of clay beds, interstadial soils, and/or subtle color changes. These zones can be correlated with, but are generally of more practical use than, previously studied dolomite zones (McKay, 1977) or clay mineral zones (Frye et al.,1968). However, mineralogical analyses can help to substantiate zone boundaries when in question. MS and compositional zones may indirectly record a climatic signal, primarily through the effect that global cooling has had on ice lobe fluctuations in the Upper Mississippi drainage basin.

Grimley, David A.; Follmer, Leon R.; McKay, E. Donald

1998-01-01

310

Magnetic Susceptibility and Mineral Zonations Controlled by Provenance in Loess along the Illinois and Central Mississippi River Valleys  

USGS Publications Warehouse

Magnetic susceptibility (MS) patterns have proven useful for regional stratigraphic correlations of zones within thick, oxidized Peoria and Roxana Silts along the Illinois and Central Mississippi River valleys for more than 350 km. Variations in MS of C horizon loess are controlled by silt-sized magnetite content and are interpreted to reflect changes in sediment provenance due to fluctuations of the Superior and Lake Michigan glacier lobes and the diversion of the Mississippi River to its present course. Grain size distributions and scanning electron microscopic observations indicate that stratigraphic changes in MS are not significantly influenced by eolian sorting or diagenetic dissolution, respectively. Three compositional zones (lower, middle, and upper) are delineated within Peoria Silt which usually can be traced in the field by MS, the occurrence of clay beds, interstadial soils, and/or subtle color changes. These zones can be correlated with, but are generally of more practical use than, previously studied dolomite zones (McKay, 1977) or clay mineral zones (Frye et al., 1968). However, mineralogical analyses can help to substantiate zone boundaries when in question. MS and compositional zones may indirectly record a climatic signal, primarily through the effect that global cooling has had on ice lobe fluctuations in the Upper Mississippi drainage basin. ?? 1998 University of Washington.

Grimley, D. A.; Follmer, L. R.; McKay, E. D.

1998-01-01

311

Parkinson's disease and residential exposure to maneb and paraquat from agricultural applications in the central valley of California.  

PubMed

Evidence from animal and cell models suggests that pesticides cause a neurodegenerative process leading to Parkinson's disease (PD). Human data are insufficient to support this claim for any specific pesticide, largely because of challenges in exposure assessment. The authors developed and validated an exposure assessment tool based on geographic information systems that integrated information from California Pesticide Use Reports and land-use maps to estimate historical exposure to agricultural pesticides in the residential environment. In 1998-2007, the authors enrolled 368 incident PD cases and 341 population controls from the Central Valley of California in a case-control study. They generated estimates for maneb and paraquat exposures incurred between 1974 and 1999. Exposure to both pesticides within 500 m of the home increased PD risk by 75% (95% confidence interval (CI): 1.13, 2.73). Persons aged < or =60 years at the time of diagnosis were at much higher risk when exposed to either maneb or paraquat alone (odds ratio = 2.27, 95% CI: 0.91, 5.70) or to both pesticides in combination (odds ratio = 4.17, 95% CI: 1.15, 15.16) in 1974-1989. This study provides evidence that exposure to a combination of maneb and paraquat increases PD risk, particularly in younger subjects and/or when exposure occurs at younger ages. PMID:19270050

Costello, Sadie; Cockburn, Myles; Bronstein, Jeff; Zhang, Xinbo; Ritz, Beate

2009-04-15

312

Methods for using groundwater model predictions to guide hydrogeologic data collection, with application to the Death Valley regional groundwater flow system  

USGS Publications Warehouse

Calibrated models of groundwater systems can provide substantial information for guiding data collection. This work considers using such models to guide hydrogeologic data collection for improving model predictions by identifying model parameters that are most important to the predictions. Identification of these important parameters can help guide collection of field data about parameter values and associated flow system features and can lead to improved predictions. Methods for identifying parameters important to predictions include prediction scaled sensitivities (PSS), which account for uncertainty on individual parameters as well as prediction sensitivity to parameters, and a new "value of improved information" (VOII) method presented here, which includes the effects of parameter correlation in addition to individual parameter uncertainty and prediction sensitivity. In this work, the PSS and VOII methods are demonstrated and evaluated using a model of the Death Valley regional groundwater flow system. The predictions of interest are advective transport paths originating at sites of past underground nuclear testing. Results show that for two paths evaluated the most important parameters include a subset of five or six of the 23 defined model parameters. Some of the parameters identified as most important are associated with flow system attributes that do not lie in the immediate vicinity of the paths. Results also indicate that the PSS and VOII methods can identify different important parameters. Because the methods emphasize somewhat different criteria for parameter importance, it is suggested that parameters identified by both methods be carefully considered in subsequent data collection efforts aimed at improving model predictions.

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

2003-01-01

313

What is the Safest Way to Cross the Valley of Death: Wisdom gained from Making a Satellite based Flood Forecasting System Operational and Owned by Stakeholders  

NASA Astrophysics Data System (ADS)

More than a decade ago, the National Research Council report popularized the term 'Valley of Death' to describe the region where research on Weather Satellites had struggled to survive before reaching maturity for societal applications. For example, the space vantage of earth observing satellites can solve some of the world's otherwise fundamentally intractable operational problems on water resources. However, recent experiences show that many of the potential beneficiaries, who are not as familiar with water cycle remote sensing missions or anthropogenic climate studies, referred here as the ';non-traditional consumers,' may have a more skeptical view based on their current practices. This talk will focus on one such non-traditional consumer group: the water resources managers/staff in developing nations of South Asia. Using real-world examples on applications and hands-on-training to make a satellite based flood forecasting system operational, the talk will dissect the view that is shared by many water managers of Bangladesh on satellite remote sensing for day to day decision making. The talk will share the experience and wisdom generated in the successful capacity building of emerging satellite technology for water management. It will end with an overview of initiatives for more effective promotion of the value of planned water cycle satellite missions for water resources management community in the developing world.

Hossain, F.

2013-12-01

314

An estimated potentiometric surface of the Death Valley region, Nevada and California, developed using geographic information system and automated interpolation techniques  

SciTech Connect

An estimated potentiometric surface was constructed for the Death Valley region, Nevada and California, from numerous, disparate data sets. The potentiometric surface was required for conceptualization of the ground-water flow system and for construction of a numerical model to aid in the regional characterization for the Yucca Mountain repository. Because accurate, manual extrapolation of potentiometric levels over large distances is difficult, a geographic-information-system method was developed to incorporate available data and apply hydrogeologic rules during contour construction. Altitudes of lakes, springs, and wetlands, interpreted as areas where the potentiometric surface intercepts the land surface, were combined with water levels from well data. Because interpreted ground-water recharge and discharge areas commonly coincide with groundwater basin boundaries, these areas also were used to constrain a gridding algorithm and to appropriately place local maxima and minima in the potentiometric-surface map. The resulting initial potentiometric surface was examined to define areas where the algorithm incorrectly extrapolated the potentiometric surface above the land surface. A map of low-permeability rocks overlaid on the potentiometric surface also indicated areas that required editing based on hydrogeologic reasoning. An interactive editor was used to adjust generated contours to better represent the natural water table conditions, such as large hydraulic gradients and troughs, or ``vees``. The resulting estimated potentiometric-surface map agreed well with previously constructed maps. Potentiometric-surface characteristics including potentiometric-surface mounds and depressions, surface troughs, and large hydraulic gradients were described.

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

1998-07-01

315

Probability distributions of hydraulic conductivity for the hydrogeologic units of the Death Valley regional ground-water flow system, Nevada and California  

SciTech Connect

The use of geologic information such as lithology and rock properties is important to constrain conceptual and numerical hydrogeologic models. This geologic information is difficult to apply explicitly to numerical modeling and analyses because it tends to be qualitative rather than quantitative. This study uses a compilation of hydraulic-conductivity measurements to derive estimates of the probability distributions for several hydrogeologic units within the Death Valley regional ground-water flow system, a geologically and hydrologicaly complex region underlain by basin-fill sediments, volcanic, intrusive, sedimentary, and metamorphic rocks. Probability distributions of hydraulic conductivity for general rock types have been studied previously; however, this study provides more detailed definition of hydrogeologic units based on lithostratigraphy, lithology, alteration, and fracturing and compares the probability distributions to the aquifer test data. Results suggest that these probability distributions can be used for studies involving, for example, numerical flow modeling, recharge, evapotranspiration, and rainfall runoff. These probability distributions can be used for such studies involving the hydrogeologic units in the region, as well as for similar rock types elsewhere. Within the study area, fracturing appears to have the greatest influence on the hydraulic conductivity of carbonate bedrock hydrogeologic units. Similar to earlier studies, we find that alteration and welding in the Tertiary volcanic rocks greatly influence conductivity. As alteration increases, hydraulic conductivity tends to decrease. Increasing degrees of welding appears to increase hydraulic conductivity because welding increases the brittleness of the volcanic rocks, thus increasing the amount of fracturing.

Belcher, W.R.; Sweetkind, D.S.; Elliott, P.E.

2002-11-19

316

Assessment of salt and nitrate sources and loading implications using a coupled surface water/groundwater model: a Central Valley example  

NASA Astrophysics Data System (ADS)

A study is underway as a key initial step in the effort by the Central Valley Salinity Coalition (CVSC) to help develop a Basin Plan amendment to address the issue of salt and nutrient management in the Central Valley. The overall objectives of the study are to develop and document procedures and methodologies to quantify the significant salt and nitrate sources in the Central Valley and to pilot those procedures in selected areas to validate the appropriateness and region-wide applicability of the procedures. The study employs the use of the Watershed Analysis Risk Management Framework (WARMF) watershed model in coordination with the finite difference groundwater flow model, MODFLOW, to evaluate salt and nitrate mass loading in three pilot study areas. Previously developed MODFLOW groundwater flow models for the Modesto and the Tule River pilot study areas will be used to provide information about recharge rates and groundwater pumpage to the WARMF model; salt and nitrate mass loads developed from the WARMF model will be shared with the groundwater models. MODFLOW with the particle tracking program, MODPATH, will then be used to provide a map of the distribution of groundwater originating from different sources using backward and forward particle tracking techniques. In a third pilot study area in Yolo County, it is planned that the recently released USGS Central Valley Hydrologic Model (CVHM), which uses advanced components of MODFLOW (MODFLOW-2000, or MF2K, including the Farm Process) will provide data such as for groundwater pumpage, deep percolation, and overland farm runoff for inputs to the WARMF domain in this study area.

Kretsinger, V.; Foglia, L.; Herr, J.; Dickey, J.; Smith, R.

2009-12-01

317

U\\/Th age constraints on the absence of ice in the central Inn Valley (eastern Alps, Austria) during Marine Isotope Stages 5c to 5a  

Microsoft Academic Search

Calcitic flowstones are present in fractures of a Pleistocene breccia near Innsbruck, Austria, and record periods of carbonate precipitation in the unsaturated zone between 101,500 ± 1500 and 70,300 ± 1800 yr, constrained by U-series disequilibrium dates. The occurrence of these speleothems, their low carbon isotopic composition, and the lack of infiltrated siliciclastic material demonstrate that the central Inn valley – which harbored one of

Christoph Spötl; Augusto Mangini

2006-01-01

318

Sedimentation and significance of the Nuia -bearing units in the Lower Middle Ordovician Antelope Valley Limestone (AVL): In central Nevada, USA  

Microsoft Academic Search

In central Nevada, theNuia pack- and grainstone lithofacies constitute the lower cliffs of the Lower Middle Ordovician Antelope Valley Limestone (AVL).\\u000a In these pack- and grainstone units,Nuia, a problematic alga, is the primary kind of particle. TheNuia pack- and grainstone lithofacies occur in the lower intervals of the AVL and are interpreted to represent the algal subtidal\\u000a shoal bars. We

Ali Kaya; Gerald M. Friedman

1997-01-01

319

Deformation in the hinge region of a chevron fold, Valley and Ridge Province, central Pennsylvania  

NASA Astrophysics Data System (ADS)

The hinge region of an asymmetrical chevron fold in sandstone, taken from the Tuscarora Formation of central Pennsylvania, U.S.A., was studied in detail in an attempt to account for the strain that produced the fold shape. The fold hinge consists of a medium-grained quartz arenite and was deformed predominantly by brittle fracturing and minor amounts of pressure solution and intracrystalline strain. These fractures include: (1) faults, either minor offsets or major limb thrusts, (2) solitary well-healed quartz veins and (3) fibrous quartz veins which are the result of repeated fracturing and healing of grains. The fractures formed during folding as they are observed to cross-cut the authigenic cement. Deformation lamellae and in a few cases, pressure solution, occurred contemporaneously with folding. The fibrous veins appear to have formed as a result of stretching of one limb: they cross-cut all other structures. Based upon the spatial relationships between the deformation features, we believe that a neutral surface was present during folding, separating zones of compression and extension along the inner and outer arcs, respectively. Using the strain data from the major faults, the fold can be restored back to an interlimb angle of 157°; however, the extension required for such an angle along the outer arc is much more than was actually measured. This disparity between observed and required deformation suggests that the rest of the folding strain may be attributed to minor faulting, isolated severe pressure solution and to slight grain movements; we were not able to recognize the latter. We propose that a single episode of deformation produced the chevron fold causing the brittle deformation after the sandstone had been lithified. This brittle deformation was accomplished by faulting together with the translation of individual sandstone blocks which do not contain significant internal deformation.

Narahara, David K.; Wiltschko, David V.

320

Late Pleistocene and Holocene environmental history of the Iguala Valley, Central Balsas Watershed of Mexico  

PubMed Central

The origin of agriculture was a signal development in human affairs and as such has occupied the attention of scholars from the natural and social sciences for well over a century. Historical studies of climate and vegetation are closely associated with crop plant evolution because they can reveal the ecological contexts of plant domestication together with the antiquity and effects of agricultural practices on the environment. In this article, we present paleoecological evidence from three lakes and a swamp located in the Central Balsas watershed of tropical southwestern Mexico that date from 14,000 B.P. to the modern era. [Dates expressed in B.P. years are radiocarbon ages. Calibrated (calendar) ages, expressed as cal B.P., are provided for dates in the text.] Previous molecular studies suggest that maize (Zea mays L.) and other important crops such as squashes (Cucurbita spp.) were domesticated in the region. Our combined pollen, phytolith, charcoal, and sedimentary studies indicate that during the late glacial period (14,000–10,000 B.P.), lake beds were dry, the climate was cooler and drier, and open vegetational communities were more widespread than after the Pleistocene ended. Zea was a continuous part of the vegetation since at least the terminal Pleistocene. During the Holocene, lakes became important foci of human activity, and cultural interference with a species-diverse tropical forest is indicated. Maize and squash were grown at lake edges starting between 10,000 and 5,000 B.P., most likely sometime during the first half of that period. Significant episodes of climatic drying evidenced between 1,800 B.P. and 900 B.P. appear to be coeval with those documented in the Classic Maya region and elsewhere, showing widespread instability in the late Holocene climate.

Piperno, D. R.; Moreno, J. E.; Iriarte, J.; Holst, I.; Lachniet, M.; Jones, J. G.; Ranere, A. J.; Castanzo, R.

2007-01-01

321

Digital Elevation Model (DEM) file of topographic elevations for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1-degree Digital Elevation Model data files  

SciTech Connect

Elevation data have been compiled into a digital data base for an {approx}100,000-km{sup 2} area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35{degree}N, long 115{degree}W, and lat 38{degree}N, long 118{degree}W. This region includes the Nevada Test Site, Yucca Mountain, and adjacent parts of southern Nevada and eastern California and encompasses the Death Valley regional ground-water system. Because digital maps are often useful for applications other than that for which they were originally intended, and because the area corresponds to a region under continuing investigation by several groups, these digital files are being released by USGS.

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

1996-04-01

322

Principal oil and gas plays in the Appalachian Basin (Province 131) (Chapter I). Middle eocene intrusive igneous rocks of the central Appalachian Valley and Ridge Province: Setting, chemistry, and implications for crustal structure (Chapter J). Bulletin  

SciTech Connect

;Contents: Principal Oil and Gas Plays in the Appalachian Basin (Province 131); and Middle Eocene Intrusive Igneous Rocks of the Central Appalachian Valley and Ridge Province - Setting, Chemistry, and Implications for Crustal Structure.

de Witt, W.; Southworth, C.S.; Gray, K.J.; Sutter, J.F.

1993-12-31

323

Cosmogenic 10Be and 36Cl geochronology of offset alluvial fans along the northern Death Valley fault zone: Implications for transient strain in the eastern California shear zone  

USGS Publications Warehouse

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 the Red Wall Canyon alluvial fan, which exposes clean dextral offsets of seven channels. Analysis of airborne laser swath mapping data indicates ???297 ?? 9 m of right-lateral displacement on the fault system since the late Pleistocene. In situ terrestrial cosmogenic 10Be and 36C1 geochronology was used to date the Red Wall Canyon fan and a second, correlative fan also cut by the fault. Beryllium 10 dates from large cobbles and boulders provide a maximum age of 70 +22/-20 ka for the offset landforms. The minimum age of the alluvial fan deposits based on 36Cl depth profiles is 63 ?? 8 ka. Combining the offset measurement with the cosmogenic 10Be date yields a geologic fault slip rate of 4.2 +1.9/-1.1 mm yr-1, whereas the 36Cl data indicate 4.7 +0.9/-0.6 mm yr-1 of slip. Summing these slip rates with known rates on the Owens Valley, Hunter Mountain, and Stateline faults at similar latitudes suggests a total geologic slip rate across the northern ECSZ of ???8.5 to 10 mm yr-1. This rate is commensurate with the overall geodetic rate and implies that the apparent discrepancy between geologic and geodetic data observed in the Mojave section of the ECSZ does not extend north of the Garlock fault. Although the overall geodetic rates are similar, the best estimates based on geology predict higher strain rates in the eastern part of the ECSZ than to the west, whereas the observed geodetic strain is relatively constant. Copyright 2007 by the American Geophysical Union.

Frankel, K. L.; Brantley, K. S.; Dolan, J. F.; Finkel, R. C.; Klinger, R. E.; Knott, J. R.; Machette, M. N.; Owen, L. A.; Phillips, F. M.; Slate, J. L.; Wernicke, B. P.

2007-01-01

324

Human effects on the hydrologic system of the Verde Valley, central Arizona, 1910–2005 and 2005–2110, using a regional groundwater flow model  

USGS Publications Warehouse

Water budgets were developed for the Verde Valley of central Arizona in order to evaluate the degree to which human stresses have affected the hydrologic system and might affect it in the future. The Verde Valley is a portion of central Arizona wherein concerns have been raised about water availability, particularly perennial base flow of the Verde River. The Northern Arizona Regional Groundwater Flow Model (NARGFM) was used to generate the water budgets and was run in several configurations for the 1910–2005 and 2005–2110 time periods. The resultant water budgets were subtracted from one another in order to quantify the relative changes that were attributable solely to human stresses; human stresses included groundwater withdrawals and incidental and artificial recharge but did not include, for example, human effects on the global climate. Three hypothetical and varied conditions of human stresses were developed and applied to the model for the 2005–2110 period. On the basis of this analysis, human stresses during 1910–2005 were found to have already affected the hydrologic system of the Verde Valley, and human stresses will continue to affect the hydrologic system during 2005–2110. Riparian evapotranspiration decreased and underflow into the Verde Valley increased because of human stresses, and net groundwater discharge to the Verde River in the Verde Valley decreased for the 1910–2005 model runs. The model also showed that base flow at the upstream end of the study area, as of 2005, was about 4,900 acre-feet per year less than it would have been in the absence of human stresses. At the downstream end of the Verde Valley, base flow had been reduced by about 10,000 acre-feet per year by the year 2005 because of human stresses. For the 2005–2110 period, the model showed that base flow at the downstream end of the Verde Valley may decrease by an additional 5,400 to 8,600 acre-feet per year because of past, ongoing, and hypothetical future human stresses. The process known as capture (or streamflow depletion caused by the pumping of groundwater) was the reason for these human-stress-induced changes in water-budget components.

Garner, Bradley D.; Pool, D. R.; Tillman, Fred D.; Forbes, Brandon T.

2013-01-01

325

Validation and future predictions based on a new Non-Point Source Assessment Toolbox, applied to the Central Valley, California  

NASA Astrophysics Data System (ADS)

Groundwater is a major irrigation water source in semi-arid regions. It is also vulnerable to Non-Point Source (NPS) contamination, particularly from nitrate (NO3-) as a result of agricultural practices. To support sound policy decisions we developed a physically based flow and transport model framework to understand and predict the fate of contaminants within regional aquifer systems. In large aquifers, the total source area of pollutants typically cover several thousand square kilometers, whilst individual sources typically do not exceed a few hundred square meters. The large contrast in these scenarios result in NPS modeling tasks that are computationally demanding, and the classical 3D models that solve the Advection-Dispersion Equation (ADE) are often not applicable due to computer memory limitations, numerical dispersion and numerical instabilities. Here, we developed and employed a number of numerical techniques to assemble a Non-Point Source Assessment Toolbox (NPSAT). The NPSAT is a quasi-3D model, combining a flow model and a streamline transport model. The flow model solves the groundwater flow equation using very fine discretization. For very large groundwater basins, a simplistic decomposition method is applied, splitting the aquifer into several overlapping sub-domains and solving to produce a high resolution velocity field. This velocity field is subsequently utilized within the transport model, where backward particle tracking links contamination sources with discharge surfaces using a large number of streamlines. For each streamline the 1D ADE is solved, assuming a unit pulse loading at the source side and a free exit boundary condition at the discharge surface side. From this, a Unit Response Function (URF) is obtained at the discharge surface side. Subsequently, actual Breakthrough Curves (BTCs) can be quickly computed from actual or hypothetical loading histories, by convoluting the URFs with real loading functions. The URFs are stored into a GIS platform and can be used for efficient scenario evaluations without the need to repeat groundwater model simulations. This method is applied to the southern third part of the Central Valley Aquifer, California, which is an intensively farmed semi-arid area, where the local communities rely heavily on groundwater. To obtain a detailed velocity field, the Central Valley Hydrologic Model (CVHM) developed by the USGS was used as the coarse solution, split and refined into a large number of sub-domains. The CVHM resolution is 1 sq mi, with the stresses applied to the center of each cell. In our refined model the well stresses are spatially distributed to a large number of hypothetical wells, where the pumping rates, well depths and screen lengths are obtained from empirical probability distributions, derived from real data. The NPSAT generates a time-dependent water quality probability distribution, which express the time-dependent probability for a discharge surface (e.g., well) to exceed a threshold level of contamination across at a specific time. The model result is compared against real historic nitrate data, and used for future predictions with different scenario evaluations.

Kourakos, G.; Harter, T.

2011-12-01

326

Compilation of data for isotope mapping of groundwater in the Central Valley of California, 1993-1995  

SciTech Connect

A major stable isotope mapping project is underway that will provide important baseline information to the State of California in management of their groundwater resources. The results represent a new technological application using isotope hydrology to better understand and predict the sustainability of California`s groundwater supply for the future. This project is driven by the fact that Californians inhabit a semi-arid region of seasonal precipitation, but have created a lifestyle and economic infrastructure requiring a sub-tropical climate. They have accomplished this by engineering systems that store and divert alpine runoff, and by utilizing a large, productive alluvial aquifer. In the past, both of these resources appeared to be unlimited. Today, water shortages are recognized, regardless of drought conditions. Because Californians maintain their current practices of prolific water use, the deep-seated competition between agricultural users and urban consumers has been amplified. This has been aggravated by the acquisition of one-third of the available surface water resources for maintenance of aquatic habitats. The State of California accepts and encourages the use of groundwater to supplement these diverse water demands. Stable isotope imaging of the groundwater resources has proven to be the most economical and effective means to diagnose the health of the giant alluvial aquifer of the Central Valley. Augmented by radiocarbon analysis and nitrate determinations, stable isotope data can be used to clearly distinguish groundwater recharged from natural or anthropogenic sources. Isotope maps delineate (1) the geographic distribution of various groundwater masses and of preferential recharge zones, (2) the sources and extent of non-point source pollution, and (3) the locations and rates of lateral flow channels. Different recharge rates of natural and modem groundwater bodies can be used to characterize safe yield parameters for aquifers.

Davisson, M.L. [Lawrence Livermore National Lab., CA (United States); Criss, R.E. [Washington Univ., St. Louis, MO (United States). Dept. of Earth and Planetary Sciences; Campbell, K.R. [Univ. of California, Davis, CA (United States). Dept. of Geology

1995-05-01

327

Late Quaternary alluvial fan response to climatic and tectonic base-level changes: Jakes Valley, Central Great Basin, USA  

NASA Astrophysics Data System (ADS)

Late Quaternary alluvial fans within the Jakes Valley region (White Pine County, Central Great Basin) are typically composed of up to 4 inset morphostratigraphic units. These units, Qf0 (oldest) through to Qf3 (youngest), are based upon field relationships (mapping & fan topographic profiles) and soil properties. Distal fan areas contain pluvial lake shoreline features (erosional benches and beach ridges) that record lake-level lowering since the last glacial maximum. Integration of the fan morphostratigraphy and pluvial lake shoreline features allows for the alluvial fan response to climate induced base-level lowering to be investigated. Geochronology is established by AMS C14 dating of gastropod shells sampled from a range of highstand (dates pending) through to lowstand (12,080 +/- 50 rcybp) beach ridges. Detailed analysis of two alluvial fans from the western (Cottonwood Fan) and eastern (Yamaha Fan) basin margins reveals some interesting differences in fan morphostratigraphy. The Cottonwood fan is characterised by a complete suite of morphostratigraphic units (Qf0-Qf3), whilst the Yamaha fan comprises only Qf0 and Qf3. The presence of a pronounced 17 m high scarp feature, some several hundreds of metres in length, within close proximity to the mountain front on the Cottonwood fan, suggests the occurrence of neotectonic activity. This extensional (?) faulting appears to be post QF0 and may have been responsible for influencing the observed stratigraphic differences between the Cottonwood and Yamaha fans via a tectonic lowering of base-level. Within this poster we explore the relative roles of climate and tectonic base-level lowering for alluvial fan development.

Stokes, M.; Garcia, A. F.

2003-12-01

328

Three-Dimensional Parameter Structure Identification: A Case Study of the Central Part of the Western San Joaquin Valley, California  

NASA Astrophysics Data System (ADS)

In this research, we propose a three-dimensional parameter structure identification procedure for a regional-scale aquifer. The procedure simultaneously identifies the parameter values, parameter pattern, and parameter dimension. These three unknowns are the values, location and number of basis points associated with a chosen parameterization. Parameter structure identification seeks to find the optimal values, location and number of basis points by minimizing the fitting residual of head observations. In this research, a universal parameterization (UP) that unifies zonation and interpolation for the inverse solution is developed. The UP generates a distribution between a pure zone structure and a continuous structure over a set of shape parameters. It shows greater flexibility in manipulating spatial distribution and spatial optimization. When a non-smooth field is investigated, the UP outperforms all other parameterization schemes. For each given level of parameter structure complexity, we have developed a global-local optimization approach, in which a genetic algorithm (GA) simultaneously searches for the ­best­" inverse solution. And then, a quasi-Newton method revisits the fitting residual minimization and improves the GA­Ýs results. We use sensitivity equation to calculate the derivatives of head with respect to the values and locations of basis points as well as the shape parameters. MODFLOW solves the groundwater flow and sensitivity equations. We demonstrate the developed methodology by a case study located in the central part of the western San Joaquin Valley, California. The unknown distributed parameter is the hydraulic conductivity of the semi-confined aquifer above the Corcoran Clay Member of the Tulare Formation. For the given set of observations, we have identified the parameter structure of the horizontal and vertical hydraulic conductivity in three dimensions with an appropriate complexity level.

Tsai, F. T.; Sun, N.; Yeh, W. W.

2002-12-01

329

Bedrock channel geometry along an orographic rainfall gradient in the upper Marsyandi River valley in central Nepal  

NASA Astrophysics Data System (ADS)

Pronounced rainfall gradients combined with spatially uniform exhumation of rocks at Quaternary timescales and uniform rock strength make the upper Marsyandi River valley in central Nepal a useful natural laboratory in which to explore variations in bedrock channel width. We focus on small catchments (0.6-12.4 km2) along a more than tenfold gradient in monsoon rainfall. Rainfall data are gathered from a dense weather network and calibrated satellite observations, the pattern of Quaternary exhumation is inferred from apatite fission track cooling ages, and rock compressive strength is measured in the field. Bedrock channel widths, surveyed at high scour indicators, scale as a power law function of discharge (w ?Qw0.38±0.09) that is estimated by combining rainfall data with 90-m digital topography. The results suggest that power law width scaling models apply (1) to regions with pronounced rainfall gradients, (2) to tributary catchments distributed across a climatically diverse region, and (3) to large, rapidly denuding orogens. An analysis of rainfall data indicates that the regional gradient of rainfall during storms that drive erosive discharge events is about half as large as the gradient of seasonal rainfall across the same area. Finally, numerical models in which the maximum rainfall is displaced significantly downstream from the headwaters predict a midcatchment zone of relatively rapid decreases in channel gradient and increases in channel concavity that are driven by locally enhanced discharge. Because differential rock uplift can produce analogous changes in gradients, the influence of rainfall gradients should be assessed before tectonic inferences are drawn.

Craddock, William H.; Burbank, Douglas W.; Bookhagen, Bodo; Gabet, Emmanuel J.

2007-09-01

330

A method for evaluating the importance of system state observations to model predictions, with application to the Death Valley regional groundwater flow system  

NASA Astrophysics Data System (ADS)

We develop a new observation-prediction (OPR) statistic for evaluating the importance of system state observations to model predictions. The OPR statistic measures the change in prediction uncertainty produced when an observation is added to or removed from an existing monitoring network, and it can be used to guide refinement and enhancement of the network. Prediction uncertainty is approximated using a first-order second-moment method. We apply the OPR statistic to a model of the Death Valley regional groundwater flow system (DVRFS) to evaluate the importance of existing and potential hydraulic head observations to predicted advective transport paths in the saturated zone underlying Yucca Mountain and underground testing areas on the Nevada Test Site. Important existing observations tend to be far from the predicted paths, and many unimportant observations are in areas of high observation density. These results can be used to select locations at which increased observation accuracy would be beneficial and locations that could be removed from the network. Important potential observations are mostly in areas of high hydraulic gradient far from the paths. Results for both existing and potential observations are related to the flow system dynamics and coarse parameter zonation in the DVRFS model. If system properties in different locations are as similar as the zonation assumes, then the OPR results illustrate a data collection opportunity whereby observations in distant, high-gradient areas can provide information about properties in flatter-gradient areas near the paths. If this similarity is suspect, then the analysis produces a different type of data collection opportunity involving testing of model assumptions critical to the OPR results.

Tiedeman, Claire R.; Ely, D. Matthew; Hill, Mary C.; O'Brien, Grady M.

2004-12-01

331

A method for evaluating the importance of system state observations to model predictions, with application to the Death Valley regional groundwater flow system  

USGS Publications Warehouse

We develop a new observation-prediction (OPR) statistic for evaluating the importance of system state observations to model predictions. The OPR statistic measures the change in prediction uncertainty produced when an observation is added to or removed from an existing monitoring network, and it can be used to guide refinement and enhancement of the network. Prediction uncertainty is approximated using a first-order second-moment method. We apply the OPR statistic to a model of the Death Valley regional groundwater flow system (DVRFS) to evaluate the importance of existing and potential hydraulic head observations to predicted advective transport paths in the saturated zone underlying Yucca Mountain and underground testing areas on the Nevada Test Site. Important existing observations tend to be far from the predicted paths, and many unimportant observations are in areas of high observation density. These results can be used to select locations at which increased observation accuracy would be beneficial and locations that could be removed from the network. Important potential observations are mostly in areas of high hydraulic gradient far from the paths. Results for both existing and potential observations are related to the flow system dynamics and coarse parameter zonation in the DVRFS model. If system properties in different locations are as similar as the zonation assumes, then the OPR results illustrate a data collection opportunity whereby observations in distant, high-gradient areas can provide information about properties in flatter-gradient areas near the paths. If this similarity is suspect, then the analysis produces a different type of data collection opportunity involving testing of model assumptions critical to the OPR results.

Tiedeman, C. R.; Ely, D. M.; Hill, M. C.; O'Brien, G. M.

2004-01-01

332

Death Valley 1/sup 0/ x 2/sup 0/ NTMS area, California and Nevada. Data report: National Uranium Resource Evaluation program, hydrogeochemical and stream sediment reconnaissance  

SciTech Connect

Results of ground water and stream sediment reconnaissance in the National Topographic Map Series (NTMS) Death Valley 1/sup 0/ x 2/sup 0/ quadrangle are presented. Stream sediment samples were collected from small streams at 649 sites or at a nominal density of one site per 20 square kilometers. Ground water samples were collected at 62 sites or at a nominal density of one site per 220 square kilometers. Neutron activation analysis results are given for uranium and 16 other elements in sediments, and for uranium and 8 other elements in ground water and surface water. Mass spectrometry results are given for helium in ground water. Field measurements and observations are reported for each site. Analytical data and field measurements are presented in tables and maps. Statistical summaries of data and a brief description of results are given. A generalized geologic map and a summary of the geology of the area are included. Key data from ground water sites include (1) water chemistry measurements (pH, conductivity, and alkalinity), (2) scintillometer readings, and (3) elemental analyses (U, Br, Cl, F, He, Mn, Na, and V). Supplementary data include site descriptors, tabulated analytical data for Al, Dy, and Mg, and histograms and cumulative frequency plots for all elements. Key data from stream sediment sites include (1) water quality measurements (2) important elemental analyses, (U, Th, Hf, Ce, Fe, Mn, Sc, Na, Ti, and V), and (3) scintillometer readings. Supplementary data from stream sediment sites include sample site descriptors (stream characteristics, vegetation, etc.), additional elemental analyses (Dy, Eu, La, Lu, Sm, and Yb), and histograms and cumulative frequency plots for all elements.

Cook, J.R.

1980-04-01

333

Physical, chemical, and biological data for detailed study of irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, 1991-92  

USGS Publications Warehouse

Because of concerns about potential effects of irrigation drainage on fish and wildlife resources and on human health, the U.S. Department of the Interior initiated a program in 1985 to assess water-quality problems associated with Federal irrigation projects in the Western United States. Physical, chemical, and biological data were collected for a detailed study of irrigation drainage in the Uncompahgre Project area and in the Grand Valley, west-central Colorado, during 1991-92. This report lists onsite measurements and concen- trations of major constituents, trace elements, and stable isotopes for surface-water- and ground-water-sampling sites. Insecticide data collected in the Grand Valley are presented. Ranges of specific-conductance measurements and dissolved- oxygen concentrations for selected wells and a daily record of water-level altitude and specific conduc- tance for a well in the Grand Valley are presented. The report presents historical water-level and dissolved-solids data for two wells in the Grand Valley. Concentrations of trace elements, major constituents, total carbon, and organic carbon in bottom-sediment, bedrock, and in aquifer-sediment samples and semiquantitative data on clay and bulk mineralogy of samples of the Mancos Shale are presented. The report contains selenium-speciation data for selected water and bottom-sediment samples and selected aquifer-test results. Biological samples collected in the Uncompahgre Project area and in the Grand Valley included aquatic plants, aquatic invertebrates, fish, birds, and bird eggs. The report lists concentrations of trace elements in biological samples collected in 1991-92. A limited number of biological samples were analyzed for pesticides, PCB's, and polycyclic aromatic hydrocarbons.

Butler, D. L.; Wright, W. G.; Hahn, D. A.; Krueger, R. P.; Osmundson, B. C.

1994-01-01

334

Central role of lactic acidosis in cancer cell resistance to glucose deprivation-induced cell death.  

PubMed

Solid tumours are dependent on glucose, but are generally glucose-deprived due to poor vascularization. Nevertheless, cancer cells can generally survive glucose deprivation better than their normal counterparts. Thus, to render cancer cells sensitive to glucose depletion may potentially provide an effective strategy for cancer intervention. We propose that lactic acidosis, a tumour microenvironment factor, may allow cancer cells to develop resistance to glucose deprivation-induced death, and that disruption of lactic acidosis may resume cancer cells' sensitivity to glucose depletion. Lactic acidosis, lactosis, or acidosis was generated by adding pure lactic acid, sodium lactate, or HCl to the culture medium. Cell death, cell cycle, autophagy, apoptosis, and gene expression profiling of the surviving cancer cells under glucose deprivation with lactic acidosis were determined. Under glucose deprivation without lactic acidosis, 90% of 4T1 cancer cells died within a single day; in a sharp contrast, under lactic acidosis, 90% of 4T1 cells died in a period of 10 days, with viable cells identified even 65 days after glucose was depleted. Upon glucose restoration, surviving cells resumed proliferation. Lactic acidosis also significantly extended survival of other cancer cells under glucose deprivation. G1/G0 arrest, autophagy induction, and apoptosis inhibition were tightly associated with lactic acidosis-mediated resistance to glucose deprivation. Lactosis alone had no effect on cell survival under glucose deprivation; acidosis alone can prolong cell survival time but is not as potent as lactic acidosis. Thus, the ability of cancer cells to resist glucose deprivation-induced cell death is conferred, at least in part, by lactic acidosis, and we envision that disrupting the lactic acidosis may resume the sensitivity of cancer cells to glucose deprivation. PMID:22190257

Wu, Hao; Ding, Zonghui; Hu, Danqing; Sun, Feifei; Dai, Chunyan; Xie, Jiansheng; Hu, Xun

2012-06-01

335

High Resolution Airborne InSAR DEM of Bagley Ice Valley, South-central Alaska: Geodetic Validation with Airborne Laser Altimeter Data  

NASA Astrophysics Data System (ADS)

Bagley Ice Valley, in the St. Elias and Chugach Mountains of south-central Alaska, is an integral part of the largest connected glacierized terrain on the North American continent. From the flow divide between Mt. Logan and Mt. St. Elias, Bagley Ice Valley flows west-northwest for some 90 km down a slope of less than 1o, at widths up to 15 km, to a saddle-gap where it turns south-west to become Bering Glacier. During 4-13 September 2000, an airborne survey of Bagley Ice Valley was performed by Intermap Technologies, Inc., using their Star-3i X-band SAR interferometer. The resulting digital elevation model (DEM) covers an area of 3243 km2. The DEM elevations are orthometric heights, in meters above the EGM96 geoid. The horizontal locations of the 10-m postings are with respect to the WGS84 ellipsoid. On 26 August 2000, 9 to 18 days prior to the Intermap Star-3i survey, a small-aircraft laser altimeter profile was acquired along the central flow line for validation. The laser altimeter data consists of elevations above the WGS84 ellipsoid and orthometric heights above GEOID99-Alaska. Assessment of the accuracy of the Intermap Star-3i DEM was made by comparison of both the DEM orthometric heights and elevations above the WGS84 ellipsoid with the laser altimeter data. Comparison of the orthometric heights showed an average difference of 5.4 +/- 1.0 m (DEM surface higher). Comparison of elevations above the WGS84 ellipsoid showed an average difference of -0.77 +/- 0.93 m (DEM surface lower). This indicates that the X-band Star-3i interferometer was penetrating the glacier surface by an expected small amount. The WGS84 comparison is well within the 3 m RMS accuracy quoted for GT-3 DEM products. Snow accumulation may have occurred, however, on Bagley Ice Valley between 26 August and 4-13 September 2000. This will be estimated using a mass balance model and used to correct the altimeter-derived surface heights. The new DEM of Bagley Ice Valley will provide a reference surface of high accuracy for glaciological and geodetic research using ICEsat and small-aircraft laser altimeter profiling of this glaciologically important region of south-central Alaska.

Muskett, R. R.; Lingle, C. S.; Echelmeyer, K. A.; Valentine, V. B.; Elsberg, D.

2001-12-01

336

Congenital central hypoventilation syndrome:PHOX2B genotype determines risk for sudden death  

Microsoft Academic Search

Summary. Objective: Children with Congenital Central Hypoventilation Syndrome (CCHS) have cardiovascular symptoms consistent with the autonomic nervous system dysregulation\\/ dysfunction (ANSD) phenotype. We hypothesized that children with CCHS would have a relationshipbetween PHOX2Bgenotypeand two clinicallyapplicable cardiovascular measures of ANSD: duration of longest r-r interval and longest corrected QT interval (QTc). Materials and Methods: We studied 501 days of Holter recordings

Jerome O. Gronli; Barbara A. Santucci; Sue E. Leurgans; Elizabeth M. Berry-Kravis; Debra E. Weese-Mayer

2008-01-01

337

Geophysical studies in the vicinity of Blue Mountain and Pumpernickel Valley near Winnemucca, north-central Nevada  

USGS Publications Warehouse

From May 2008 to September 2009, the U.S. Geological Survey (USGS) collected data from more than 660 gravity stations, 100 line-km of truck-towed magnetometer traverses, and 260 physical-property sites in the vicinity of Blue Mountain and Pumpernickel Valley, northern Nevada (fig. 1). Gravity, magnetic, and physical-property data were collected to study regional crustal structures as an aid to understanding the geologic framework of the Blue Mountain and Pumpernickel Valley areas, which in general, have implications for mineral- and geothermal-resource investigations throughout the Great Basin.

Ponce, David A.

2012-01-01

338

76 FR 30938 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...  

Federal Register 2010, 2011, 2012, 2013

...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams; Release...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams (EPA...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams...

2011-05-27

339

75 FR 18499 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...  

Federal Register 2010, 2011, 2012, 2013

...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams AGENCY...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian...

2010-04-12

340

Farmers adoption and propensity to abandoned adoption of sawah-based rice farming in the inland valley of central Nigeria  

Microsoft Academic Search

This paper describes a process of technology dissemination to rice farmers cultivating inland valleys in Nigeria. The sawah-based rice production technology is an adapted rice production technology system in Asia, which consists of leveled field surrounded by banks with inlet and outlet connecting irrigation and drainage canals, row transplanting of improved variety and fertilizer application. The sawah system has contributed

Regina Hoi; Yee Fu; Makoto Maruyama; O. Idowu Oladele; Toshiyuki Wakatsuki

341

Source rocks, thermal history and oil in the Carson Sink and Buena Vista Valley, west central Nevada  

Microsoft Academic Search

Rock-Eval, gas chromatography, mass spectrometry, and thermal history reconstruction data from six wells suggest that Tertiary rocks in the Carson Sink and Buena Vista Valley areas are marginally mature to overmature with respect to hydrocarbon generation and have locally expelled oil. The lacustrine Tertiary calcareous mudstones and marls in these wells have a total organic carbon (TOC) range from 0.1

Charles E. Barker

1995-01-01

342

NADPH oxidase plays a central role in cone cell death in retinitis pigmentosa.  

PubMed

Retinitis pigmentosa (RP) is a collection of diseases in which rod photoreceptors die from a variety of mutations. After rods die, the level of tissue oxygen in the outer retina becomes elevated and there is progressive oxidative damage to cones that ultimately triggers apoptosis. In this study, we investigated the hypothesis that NADPH oxidase (Nox) and/or xanthine oxidase serve as critical intermediaries between increased tissue oxygen and the generation of excessive reactive oxygen species that cause oxidative damage to cones. Apocynin, a blocker of Nox, but not allopurinol, a blocker of xanthine oxidase, markedly reduced the superoxide radicals visualized by hydroethidine in the outer retina in the retinal degeneration-1 (rd1(+/+)) model of RP. Compared to rd1(+/+) mice treated with vehicle, those treated with apocynin, but not those treated with allopurinol, had significantly less oxidative damage in the retina measured by ELISA for carbonyl adducts. Apocynin-treated, but not allopurinol-treated, rd1(+/+) mice had preservation of cone cell density, increased mRNA levels for m- and s-cone opsin, and increased mean photopic b-wave amplitude. In Q344ter mice, a model of dominant RP in which mutant rhodopsin is expressed, apocynin treatment preserved photopic electroretinogram b-wave amplitude compared to vehicle-treated controls. These data indicate that Nox, but not xanthine oxidase, plays a critical role in generation of the oxidative stress that leads to cone cell death in RP and inhibition of Nox provides a new treatment strategy. PMID:19493169

Usui, Shinichi; Oveson, Brian C; Lee, Sun Young; Jo, Young-Joon; Yoshida, Tsunehiko; Miki, Akiko; Miki, Katsuaki; Iwase, Takeshi; Lu, Lili; Campochiaro, Peter A

2009-08-01

343

Dopamine induces cell death, lipid peroxidation and DNA base damage in a catecholaminergic cell line derived from the central nervous system  

Microsoft Academic Search

Dopamine can be autoxidized to superoxides and quinones. Superoxides can form hydroxyl radicals that are highly reactive with\\u000a lipids, proteins and DNA leading to neuronal damage and cell death. We used a clonal catecholaminergic cell line (CATH.a)\\u000a derived from the central nervous system to evaluate the effects of dopamine on cell death, lipid peroxidation and DNA base\\u000a damage. Dopamine produces

Joseph M. Masserano; Ivory Baker; Diane Venable; Li Gong; Steven J. Zullo; Carl R. Merril; Richard Jed Wyatt

1999-01-01

344

Assessing the Vulnerability of Public-Supply Wells to Contamination: Central Valley Aquifer System near Modesto, California  

USGS Publications Warehouse

This fact sheet highlights findings from the vulnerability study of a public-supply well in Modesto, California. The well selected for study pumps on average about 1,600 gallons per minute from the Central Valley aquifer system during peak summer demand. Water samples were collected at the public-supply well and at monitoring wells installed in the Modesto vicinity. Samples from the public-supply wellhead contained the undesirable constituents uranium, nitrate, arsenic, volatile organic compounds (VOCs), and pesticides, although none were present at concentrations exceeding drinking-water standards. Of these contaminants, uranium and nitrate pose the most significant water-quality risk to the public-supply well because human activities have caused concentrations in groundwater to increase over time. Overall, study findings point to four primary factors that affect the movement and (or) fate of contaminants and the vulnerability of the public-supply well in Modesto: (1) groundwater age (how long ago water entered, or recharged, the aquifer); (2) irrigation and agricultural and municipal pumping that drives contaminants downward into the primary production zone of the aquifer; (3) short-circuiting of contaminated water down the public-supply well during the low-pumping season; and (4) natural geochemical conditions of the aquifer. A local-scale computer model of groundwater flow and transport to the public-supply well was constructed to simulate long-term nitrate and uranium concentrations reaching the well. With regard to nitrate, two conflicting processes influence concentrations in the area contributing recharge to the well: (1) Beneath land that is being farmed or has recently been farmed (within the last 10 to 20 years), downward-moving irrigation waters contain elevated nitrate concentrations; yet (2) the proportion of agricultural land has decreased and the proportion of urban land has increased since 1960. Urban land use is associated with low nitrate concentrations in recharge (3.1 milligrams per liter). Results of the simulation indicate that nitrate concentrations in the public-supply well peaked in the late 1990s and will decrease slightly from the current level of 5.5 milligrams per liter during the next 100 years. A lag time of 20 to 30 years between peak nitrate concentrations in recharge and peak concentrations in the well is the result of the wide range of ages of water reaching the public-supply well combined with changing nitrogen input concentrations over time. As for uranium, simulation results show that concentrations in the public-supply well will likely approach the Maximum Contaminant Level of 30 micrograms per liter over time; however, it will take more than 100 years because of the contribution of old water at depth in the public-supply well that dilutes uranium concentrations in shallower water entering the well. This allows time to evaluate management strategies and to alter well-construction or pumping strategies to prevent uranium concentrations from exceeding the drinking-water standard.

Jagucki, Martha L.; Jurgens, Bryant C.; Burow, Karen R.; Eberts, Sandra M.

2009-01-01

345

Stratigraphy of the Arriaga Palaeolithic sites. Implications for the geomorphological evolution recorded by thickened fluvial sequences within the Manzanares River valley (Madrid Neogene Basin, Central Spain)  

NASA Astrophysics Data System (ADS)

The Arriaga Palaeolithic sites, located within the Middle-Late Pleistocene thickened terrace (TCMZ: + 18-22 m) of the Manzanares River valley (Madrid, Central Spain), were subject to intensive archaeological and palaeontological prospecting during the 1980s. Compilation of documents from these old excavations, together with new geoarchaeological, sedimentological, pedological and geophysical data, allow us to locate the morpho-stratigraphic position of the analysed sites within the overall stratigraphy of the TCMZ. This thickened terrace comprises two main fluvial sequences (Lower and Upper) topped by a thick (2.5-5 m) alluvial-colluvial formation. The fluvial sequences are stacked in the study site located in the lowermost reach of the valley, but display complex inset relationships upstream, where they are individualized in two different terrace levels at + 18-22 and + 12-15 m. Terrace thickening was primarily controlled by synsedimentary subsidence caused by dissolution of the evaporitic substratum and locally influenced and backfed by tectonic activity. The regional analysis of the dated (TL and OSL) fluvial sequences containing Palaeolithic sites within the TCMZ, together with new TL dates provided in this study, indicate that the three sedimentary sequences in the TCMZ are time-transgressive valley-fill bodies. Terrace thickening started before the Last Interglacial Period (MIS 6 or older) and continued during whole MIS 5 (lower fluvial sequence) and MIS 4 (upper fluvial sequence) reaching the MIS 3 (top alluvial formation), the latter characterized by the accumulation of alluvial-colluvial sequences derived from the main tributaries and valley slopes. The TCMZ records the Middle-Late Pleistocene boundary, but also the transition between the Lower and Middle Palaeolithic periods during the Late MIS 5 (ca. 96 to 74 ka). The studied Arriaga sites contain evolved Lower Palaeolithic industry (evolved Acheulean techno-complexes) and warm faunal assemblages located within the Lower fluvial sequence, but apparently well constrained Middle Palaeolithic sites are placed within the Upper fluvial sequence at other upstream locations. Deposition of the thickened alluvium was mainly controlled by the upstream advance of dissolution-induced subsidence phenomena, blurring the impact of Late Pleistocene climatic cycles and producing time-transgressive longitudinal valley-fill bodies (i.e. sedimentary sequences). Late Quaternary climatic changes only seem to control the incision/aggradation cycles after the termination of the TCMZ from the Late MIS 3. Dates related to the development of younger inset terraces indicate that they are apparently linked with cold Heinrich events H4 to H1. These younger inset terraces yield cold faunal assemblages and abundant Middle Palaeolithic "Mousterian" assemblages.

Silva, P. G.; López-Recio, M.; Tapias, F.; Roquero, E.; Morín, J.; Rus, I.; Carrasco-García, P.; Giner-Robles, J. L.; Rodríguez-Pascua, M. A.; Pérez-López, R.

2013-08-01

346

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

Federal Register 2010, 2011, 2012, 2013

...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams AGENCY...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams...data used to derive a benchmark for conductivity. The original Federal Register...

2010-08-18

347

75 FR 30393 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...  

Federal Register 2010, 2011, 2012, 2013

...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams AGENCY...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams...data used to derive a benchmark for conductivity. By following the link below,...

2010-06-01

348

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

Federal Register 2010, 2011, 2012, 2013

...Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams AGENCY...Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams...data used to derive a benchmark for conductivity. The original Federal Register...

2010-07-13

349

Digital tabulation of stratigraphic data from oil and gas wells in Cuyama Valley and surrounding areas, central California  

USGS Publications Warehouse

Stratigraphic information from 391 oil and gas exploration wells from Cuyama Valley, California, and surrounding areas are herein compiled in digital form from reports that were released originally in paper form. The Cuyama Basin is located within the southeasternmost part of the Coast Ranges and north of the western Transverse Ranges, west of the San Andreas fault. Knowledge of the location and elevation of stratigraphic tops of formations throughout the basin is a first step toward understanding depositional trends and the structural evolution of the basin through time, and helps in understanding the slip history and partitioning of slip on San Andreas and related faults.

Sweetkind, Donald S.; Bova, Shiera C.; Langenheim, Victoria E.; Shumaker, Lauren E.; Scheirer, Daniel S.

2013-01-01

350

Regional soil geochemistry in the Ojailen Valley: a realm dominated by the industrial and mining city of Puertollano (South Central Spain)  

NASA Astrophysics Data System (ADS)

Regional soil geochemistry in the Ojailén Valley: a realm dominated by the industrial and mining city of Puertollano (South Central Spain). Authors: Miguel A. López-Berdonces¹; Sergio Fernández Calderón¹; Pablo Higueras¹; José María Esbrí¹; Beatriz González-Corrochano¹; Eva Mª García-Noguero¹; Alba Martínez-Coronado¹; Carolina García Noguero¹ ¹Instituto de Geología Aplicada, Universidad de Castilla La Mancha, Almadén 13400 (Spain). Ojailén Valley is situated in South Central of Spain, an area where livestock, agriculture, mining and industry coexist. This work tries to assess the relationships between these activities and local environmental compartments: water, soils and heavy metal contents, and establish the most appropriate methodology of sample treatment and analytical techniques that can be employed on this kind of studies. For soil geochemistry, 152 samples were taken at two different depths, one at surface layer and another at 20 cm depth, and establish relationships between them and the possible sources. For this purpose, we determine soil parameters (pH, conductivity and organic matter) and total metal contents by Energy Dispersion of X Ray Fluorescence (EDXRF). Samples with higher nickel contents were analyzed with Inductive Coupled Plasma Spectroscopy (ICP-OES) after acid digestion. The study of surface waters includes 18 samples along the river and tributaries near mining and industrial areas. Water analysis was performed by ICP-OES. Soil samples shows pH between 6 and 8.5, highest located near on the east part of the valley, in the vicinity of petrochemical complex. Conductivity values show higher levels (1600 µS cm¯¹) in the vicinity of Puertollano and the industrial sites. Local reference value (LRV) for contaminated soils were determined according to the methodology proposed by Jimenez-Ballesta et al. (2010), using the equation: LRV=GM + 2SD, where LRV: Local Reference Value, GM: Geometric Mean, SD: Standard Deviation. Trace metals values are significantly higher than calculated LRV, especially for Zn, Pb, (Average content: 230 mg kg¯¹ and 249.9 mg kg¯¹ respectively), probable due to Pb-Zn mining in the nearest Alcudia valley. Other elements seem to be influenced by petrochemical industry (Ni, V, and Cu) with LRV: 199.9 mg kg¯¹, 39.2 mg kg¯¹ and 184.2 mg kg¯¹ respectively. Most water samples have metal contents higher than levels for drinking water (WHO, 2006), especially Fe and Pb with 20 µg l¯¹ and 10 µg l¯¹ respectively. Higher metal contents were located on three different sites: downstream an open-pit coal mine, in stagnant water where we can find an old sewage treatment plant, and downstream a photovoltaic plant built in 2008. We can consider that Ojailén Valley is not an area with high contents in heavy metals in the environment, but Puertollano and its petrochemical complex have contents in Pb, Zn, Cu, As, Ni above the LRV. A comparison of results obtained by ICP-MS and XRF related to Pb, Zn, Cr, Ni in thirty-four selected samples, we can conclude that both techniques are qualitatively agree, although XRF cannot be considered suitable for establishing reference legal limits. References Jiménez-Ballesta, R; Conde-Bueno,P; Martin-Rubí,J.A.; García-Jímenez,R. 2010. Geochemical baseline contents levels and soil quality reference values of trace elements in soils from the Mediterranean (Castilla-La Mancha, Spain). Central European Journal of Geosciences 2, 441-454. WHO2006. Guidelines for drinking- water quality, Vol.1, 3rd edition incorporating 1st and 2nd addenda. (http//www.who.int/entity/water_sanitation_health/dwq/fulltext.pdf) Geneve, Suiza.

López-Berdonces, Miguel; Fernandez-Calderón, Sergio; Higueras, Pablo; María Esbrí, Jose; Gonzalez-Corrochano, Beatríz; García-Noguero, Eva Mª; Martínez-Coronado, Alba; García-Noguero, Carolina

2013-04-01

351

A regression model for the temporal development of soil pipes and associated gullies in the alluvial-fill valley of the Rio Puerco, central New Mexico  

NASA Technical Reports Server (NTRS)

On Mars, the association of gullied escarpments and chaotic terrain is evidence for failure and scarp retreat of poorly consolidated materials. Some martian gullies have no surface outlets and may have drained through subterranean channels. Similar features, though on a much smaller scale, can be seen in alluvium along terrestrial river banks in semiarid regions, such as the Rio Puerco Valley of central New Mexico. Many of the escarpments along the Rio Puerco are developing through formation of collapse gullies, which drain through soil pipes. Gully development can be monitored on aerial photographs taken in 1935, 1962, and 1980. A regression model was developed to quantify gully evolution over a known time span. Soil pipes and their associated collapse gullies make recognizable signatures on the air photos. The areal extent of this signature can be normalized to the scarp length of each pipe-gully system, which makes comparisons between systems possible.

Condit, C. D.; Elston, W. E.

1984-01-01

352

Airborne Measurements of Ammonia and Implications for Ammonium Nitrate Formation in the Central Valley and the South Coast Air Basin of California  

NASA Astrophysics Data System (ADS)

Ammonia (NH3) is the dominant gas-phase base in the troposphere. As a consequence, NH3 abundance influences aerosol formation and composition. Ammonium nitrate aerosol is formed from the reaction of gas phase NH3 and nitric acid (HNO3). Anthropogenic emissions of NH3 and NOx (NO + NO2), which in sunlight can be oxidized to form HNO3, can react to form ammonium nitrate aerosol. Agricultural activity (i.e., dairy farms), and urban centers (i.e., Fresno, Los Angeles) are sources of ammonium nitrate gas-phase precursors in both the Central Valley and the South Coast Air Basin. Airborne measurements of NH3, HNO3, particle composition, and particle size distribution were made aboard the NOAA WP-3D research aircraft during May and June 2010 in the Central Valley and the South Coast Air Basin of California, as part of CalNex 2010 (California Research at the Nexus of Air Quality and Climate Change). The highest mixing ratios of NH3, well over 100 parts-per-billion by volume (ppbv), were measured downwind of dairy farms. The high NH3 mixing ratios were highly anti-correlated with HNO3 mixing ratios on fast time scales (~1 s) that correspond to short flight distances (~100 m). During these periods particulate nitrate (NO3-) concentrations increased, indicating ammonium nitrate formation. The meteorological and chemical environments during these periods will be studied to determine the factors driving or limiting ammonium nitrate formation and the resulting regional differences. Finally, the relationship between the NH3 observations and NH3 sources will be examined to assess the emissions and their contribution to ammonium nitrate abundance.

Nowak, J. B.; Neuman, J.; Bahreini, R.; Middlebrook, A. M.; Brock, C. A.; Frost, G. J.; Holloway, J. S.; McKeen, S. A.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Trainer, M.; Parrish, D. D.

2010-12-01

353

Water circulation within a high-Arctic glaciated valley (Petunia Bay, Central Spitsbergen): Recharge of a glacial river  

NASA Astrophysics Data System (ADS)

This article presents an investigation of the runoff of a glacial river located in the high Arctic region of Spitsbergen. The Ebba River runoff was measured during three melting seasons of 2007, 2008 and 2009. The most important component of the river recharge is the flow of melting water from glaciers (76-82% of total river runoff). However, the other components (surface water and groundwater) also made a significant contribution to the river recharge. The contribution of groundwater flow in total river runoff was estimated by measurements performed in four groups of piezometers located in different parts of the valley. The hydrogeological parameters that characterize shallow aquifer (thickness of the active layer, hydraulic conductivity, groundwater level fluctuations) were recognized by direct field measurements. The groundwater recharging river was the most variable recharge component, and ranged from 1% of the total runoff at the beginning of the melting season to even 27% at the end of summer.

Marciniak, Marek; Dragon, Krzysztof; Chudziak, ?ukasz

2014-05-01

354

An 11??000-year-long record of fire and vegetation history at Beaver Lake, Oregon, central Willamette Valley  

USGS Publications Warehouse

High-resolution macroscopic charcoal and pollen analysis were used to reconstruct an 11??000-year-long record of fire and vegetation history from Beaver Lake, Oregon, the first complete Holocene paleoecological record from the floor of the Willamette Valley. In the early Holocene (ca 11??000-7500 calendar years before present [cal??yr??BP]), warmer, drier summers than at present led to the establishment of xeric woodland of Quercus, Corylus, and Pseudotsuga near the site. Disturbances (i.e., floods, fires) were common at this time and as a result Alnus rubra grew nearby. High fire frequency occurred in the early Holocene from ca 11??200-9300??cal??yr??BP. Riparian forest and wet prairie developed in the middle Holocene (ca 7500??cal??yr??BP), likely the result of a decrease in the frequency of flooding and a shift to effectively cooler, wetter conditions than before. The vegetation at Beaver Lake remained generally unchanged into the late Holocene (from 4000??cal??yr??BP to present), with the exception of land clearance associated with Euro-American settlement of the valley (ca 160??cal??yr BP). Middle-to-late Holocene increases in fire frequency, coupled with abrupt shifts in fire-episode magnitude and charcoal composition, likely indicate the influence anthropogenic burning near the site. The paleoecological record from Beaver Lake, and in particular the general increase in fire frequency over the last 8500??years, differs significantly from other low-elevation sites in the Pacific Northwest, which suggests that local controls (e.g., shifts in vegetation structure, intensification of human land-use), rather than regional climatic controls, more strongly influenced its environmental history. ?? 2010 Elsevier Ltd.

Walsh, M. K.; Pearl, C. A.; Whitlock, C.; Bartlein, P. J.; Worona, M. A.

2010-01-01

355

Hydrology of the Mississippi River Valley alluvial aquifer, south- central United States; a preliminary assessment of the regional flow system  

USGS Publications Warehouse

Data describing the aquifer framework and steady-state regional flow were assembled for the Mississippi River Valley alluvial aquifer north of Vicksburg, Mississippi. The aquifer is part of the Mississippi embayment aquifer system. The 60 to 140 ft thick alluvial aquifer grades from gravel at the bottom to fine sand near the top. It is overlain by the Mississippi River Valley confining unit, which consists of 10 to 50 ft of silts, clays, and fine-grained sands. Underlying units consist of alternating sands and clays corresponding to regional hydrogeologic units of the Mississippi embayment aquifer system. The three-layer finite difference model was used to simulate two-dimensional confined or unconfined steady-state flow for predevelopment and 1972. Preliminary analysis of predevelopment flow indicates that recharge to the alluvial aquifer was from underlying aquifers and the confining unit. Rivers accounted for almost all discharge. Pumpage from the alluvial aquifer for irrigation substantially changed regional flow direction toward depressions in the potentiometric surface. Recharge from rivers and the confining unit increased and recharge from underlying aquifers decreased. Discharge to underlying aquifers increased and discharge to rivers decreased. Recharge from the confining unit reached a maximum of 1.3 inch/year for large parts of the aquifer. Nearly all drawdown exceeding 20 ft was at two locations in Arkansas--the Grande Prairie region, and west of Crowleys Ridge. Model results indicate the importance of leakage from rivers and the confining unite to providing recharge to sustain large amounts of pumpage from the alluvial aquifer. (USGS)

Ackerman, D. J.

1989-01-01

356

Late Glacial and early Holocene environment in the middle Lahn river valley (Hessen, central-west Germany) and the local impact of early Mesolithic people—pollen and macrofossil evidence  

Microsoft Academic Search

The Late Glacial to early Holocene river valley landscape of the middle Lahntal in Hessen, central-west Germany, is reconstructed by means of pollen and macrofossil analyses. AMS 14C dating combined with pollen, macrofossil and geomorphological mapping provide a detailed chronology of the floodplain sediments of the river Lahn. Archaeological evidence for early Mesolithic settlements in the middle Lahntal is backed

Johanna A. A. Bos; Ralf Urz

2003-01-01

357

THE SLOW DEATH (OR REBIRTH?) OF EXTENDED STAR FORMATION IN z {approx} 0.1 GREEN VALLEY EARLY-TYPE GALAXIES  

SciTech Connect

UV observations in the local universe have uncovered a population of early-type galaxies with UV flux consistent with low-level recent or ongoing star formation. Understanding the origin of such star formation remains an open issue. We present resolved UV-optical photometry of a sample of 19 Sloan Digital Sky Survey (SDSS) early-type galaxies at z {approx} 0.1 drawn from the sample originally selected by Salim and Rich to lie in the bluer part of the green valley in the UV-optical color-magnitude diagram as measured by the Galaxy Evolution Explorer (GALEX). Utilizing high-resolution Hubble Space Telescope (HST) far-UV imaging provides unique insight into the distribution of UV light in these galaxies, which we call ''extended star-forming early-type galaxies'' (ESF-ETGs) because of extended UV emission that is indicative of recent star formation. The UV-optical color profiles of all ESF-ETGs show red centers and blue outer parts. Their outer colors require the existence of a significant underlying population of older stars in the UV-bright regions. An analysis of stacked SDSS spectra reveals weak LINER-like emission in their centers. Using a cross-matched SDSS DR7/GALEX GR6 catalog, we search for other green valley galaxies with similar properties to these ESF-ETGs and estimate that Almost-Equal-To 13% of dust-corrected green valley galaxies of similar stellar mass and UV-optical color are likely ESF-candidates, i.e., ESF-ETGs are not rare. Our results are consistent with star formation that is gradually declining in existing disks, i.e., the ESF-ETGs are evolving onto the red sequence for the first time, or with rejuvenated star formation due to accreted gas in older disks provided that the gas does not disrupt the structure of the galaxy and the resulting star formation is not too recent and bursty. ESF-ETGs may typify an important subpopulation of galaxies that can linger in the green valley for up to several Gyrs, based on their resemblance to nearby gas-rich green valley galaxies with low-level ongoing star formation.

Fang, Jerome J.; Faber, S. M. [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Salim, Samir [Department of Astronomy, Indiana University, Bloomington, IN 47404 (United States); Graves, Genevieve J. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Rich, R. Michael, E-mail: jjfang@ucolick.org [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

2012-12-10

358

Precipitation and runoff simulations of select perennial and ephemeral watersheds in the middle Carson River basin, Eagle, Dayton, and Churchill Valleys, west-central Nevada  

USGS Publications Warehouse

The effect that land use may have on streamflow in the Carson River, and ultimately its impact on downstream users can be evaluated by simulating precipitation-runoff processes and estimating groundwater inflow in the middle Carson River in west-central Nevada. To address these concerns, the U.S. Geological Survey, in cooperation with the Bureau of Reclamation, began a study in 2008 to evaluate groundwater flow in the Carson River basin extending from Eagle Valley to Churchill Valley, called the middle Carson River basin in this report. This report documents the development and calibration of 12 watershed models and presents model results and the estimated mean annual water budgets for the modeled watersheds. This part of the larger middle Carson River study will provide estimates of runoff tributary to the Carson River and the potential for groundwater inflow (defined here as that component of recharge derived from percolation of excess water from the soil zone to the groundwater reservoir). The model used for the study was the U.S. Geological Survey's Precipitation-Runoff Modeling System, a physically based, distributed-parameter model designed to simulate precipitation and snowmelt runoff as well as snowpack accumulation and snowmelt processes. Models were developed for 2 perennial watersheds in Eagle Valley having gaged daily mean runoff, Ash Canyon Creek and Clear Creek, and for 10 ephemeral watersheds in the Dayton Valley and Churchill Valley hydrologic areas. Model calibration was constrained by daily mean runoff for the 2 perennial watersheds and for the 10 ephemeral watersheds by limited indirect runoff estimates and by mean annual runoff estimates derived from empirical methods. The models were further constrained by limited climate data adjusted for altitude differences using annual precipitation volumes estimated in a previous study. The calibration periods were water years 1980-2007 for Ash Canyon Creek, and water years 1991-2007 for Clear Creek. To allow for water budget comparisons to the ephemeral models, the two perennial models were then run from 1980 to 2007, the time period constrained somewhat by the later record for the high-altitude climate station used in the simulation. The daily mean values of precipitation, runoff, evapotranspiration, and groundwater inflow simulated from the watershed models were summed to provide mean annual rates and volumes derived from each year of the simulation. Mean annual bias for the calibration period for Ash Canyon Creek and Clear Creek watersheds was within 6 and 3 percent, and relative errors were about 18 and -2 percent, respectively. For the 1980-2007 period of record, mean recharge efficiency and runoff efficiency (percentage of precipitation as groundwater inflow and runoff) averaged 7 and 39 percent, respectively, for Ash Canyon Creek, and 8 and 31 percent, respectively, for Clear Creek. For this same period, groundwater inflow volumes averaged about 500 acre-feet for Ash Canyon and 1,200 acre-feet for Clear Creek. The simulation period for the ephemeral watersheds ranged from water years 1978 to 2007. Mean annual simulated precipitation ranged from 6 to 11 inches. Estimates of recharge efficiency for the ephemeral watersheds ranged from 3 percent for Eureka Canyon to 7 percent for Eldorado Canyon. Runoff efficiency ranged from 7 percent for Eureka Canyon and 15 percent at Brunswick Canyon. For the 1978-2007 period, mean annual groundwater inflow volumes ranged from about 40 acre-feet for Eureka Canyon to just under 5,000 acre-feet for Churchill Canyon watershed. Watershed model results indicate significant interannual variability in the volumes of groundwater inflow caused by climate variations. For most of the modeled watersheds, little to no groundwater inflow was simulated for years with less than 8 inches of precipitation, unless those years were preceded by abnormally high precipitation years with significant subsurface storage carryover.

Jeton, Anne E.; Maurer, Douglas K.

2011-01-01

359

Hydrologic and geologic characteristics of the Yucca Mountain site relevant to the performance of a potential repository: Day 1, Las Vegas, Nevada to Pahrump, Nevada: Stop 6A. Keane Wonder Spring and regional groundwater flow in the Death Valley region  

USGS Publications Warehouse

Yucca Mountain, located ~100 mi northwest of Las Vegas, Nevada, has been designated by Congress as a site to be characterized for a potential mined geologic repository for high-level radioactive waste. This field trip will examine the regional geologic and hydrologic setting for Yucca Mountain, as well as specific results of the site characterization program, The first day focuses on the regional seeing with emphasis on current and paleo hydrology, which are both of critical concern for predicting future performance of a potential repository. Morning stops will be in southern Nevada and afternoon stops will be in Death Valley. The second day will be spent at Yucca Mountain. The filed trip will visit the underground testing sites in the "Exploratory Studies Facility" and the "Busted Butte Unsaturated Zone Transport Field Test" plus several surface-based testing sites. Much of the work at the site has concentrated on studies of the unsaturated zone, and element of the hydrologic system that historically has received little attention. Discussions during the second day will comprise selected topics of Yucca Mountain geology, mic hazard in the Yucca Mountain area. Evening discussions will address modeling of regional groundwater flow, the geology and hydrology of Yucca Mountain to the performance of a potential repository. Day 3 will examine the geologic framework and hydrology of the Pahute Mesa-Oasis Valley Groundwater Basin and then will continue to Reno via Hawthorne, Nevada and the Walker Lake area.

Steinkampf, W.C.

2000-01-01