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1

Structure and regional significance of the Late Permian(?) Sierra Nevada-Death Valley thrust system, east-central California  

NASA Astrophysics Data System (ADS)

An imbricate system of north-trending, east-directed thrust faults of late Early Permian to middle Early Triassic (most likely Late Permian) age forms a belt in east-central California extending from the Mount Morrison roof pendant in the eastern Sierra Nevada to Death Valley. Six major thrust faults typically with a spacing of 15-20 km, original dips probably of 25-35°, and stratigraphic throws of 2-5 km compose this structural belt, which we call the Sierra Nevada-Death Valley thrust system. These thrusts presumably merge into a décollement at depth, perhaps at the contact with crystalline basement, the position of which is unknown. We interpret the deformation that produced these thrusts to have been related to the initiation of convergent plate motion along a southeast-trending continental margin segment probably formed by Pennsylvanian transform truncation. This deformation apparently represents a period of tectonic transition to full-scale convergence and arc magmatism along the continental margin beginning in the Late Triassic in central California.

Stevens, Calvin H.; Stone, Paul

2005-12-01

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

Age and Elevations of High-Level OIS2 Pluvial Lake Manly Shorelines, Northern and Central Death Valley: Implications for Lacustrine Sequence Stratigraphy in Southern Death Valley and the OIS6 Pluvial Lake Level  

NASA Astrophysics Data System (ADS)

New 14C ages of algal tufa from high-level Lake Manly shorelines at the Beatty Bar Complex (BBC) in Northern Death Valley (NDV) and on the west flank of the Black Mountains in Central Death Valley (CDV) indicate that shoreline features at elevations of up to 46 m and 61 m, respectively, formed during the latest- Pleistocene, OIS2 pluvial-lake cycle rather than the earlier OIS6 lake cycle as commonly interpreted. In-situ algal tufa clast coatings in the highest shoreline gravel bar at the BBC yielded an age of 26.97±0.62 14C kyrs B.P. The prominent horizon of tufa coatings lies ~1.5 m below the bar crest (46 m) and is interpreted to mark the static elevation of the OIS2 Lake Manly highstand. The tufa age is consistent with the gravel bar's youthful geomorphic expression and generally weak soil development, a previously reported TL age of 24.0±2.5 ka from fine-grained lagoonal(?) deposits behind this same gravel bar (45 m), a thinolitc-tufa age of 16.40-15.75 cal yrs B.P. from Mesquite Flat (37 m), and U-series ages (9.6±3.3 and 30.1±3.3 ka) and associated deep-lake ostracodes from core in CDV. In CDV, 2.5 km north of Badwater, prominent shoreline beach rock and algal tufa lie in deposition against the steep footwall escarpment of Black Mountains fault zone (BMFZ) to an elevation of ~61 m. Algal tufa collected at ~55 m yielded an age of 24.55±0.33 14C kyrs B.P. indicating that OIS2 Lake Manly highstand shorelines in CDV now lie at least 15 m higher than in NDV. The lack of major vertical-slip-rate faults in NDV suggests absolute footwall uplift adjacent to the prominent BMFZ (ala Borah Peak) may account for the difference. In Southern Death Valley (SDV), new mapping and tephra ages have defined a series of 3 lacustrine sequences well exposed along eastern traces of the Southern Death Valley fault zone (SDVFZ): 1) a lower sequence of highly-folded, late-Pliocene strata containing ~3.4 Ma Mesquite Springs tephra (correlative to strata in the eastern Noble Hills); 2) a gently- folded middle sequence of early-to-middle-Pleistocene strata containing Glass Mountain (1.2-0.9 Ma) and Lava Creek (0.64 Ma) tephra (age-correlative to strata in the Confidence Hills); and 3) a non-folded upper sequence, which is not dated, but clearly unconformably overlies the folded middle sequence. The upper sequence also shows only minor displacement along the SDVFZ. The upper sequence lies at a maximum elevation of ~45 m, the same as the BBC highstand gravel bar 100 km to the north. Hence, we correlate the undeformed upper lacustrine sequence in SDV to the OIS2 phase of Lake Manly. Although previously dated OIS6 shorelines (120-186 ka) along the Black Mountains escarpment lie at an elevation of ~90 m, we have yet to identify an OIS6 sequence of lacustrine deposits in SDV. Again, following the concept of absolute footwall uplift along the BMFZ, it is possible that the OIS6 Lake Manly highstand was considerably lower than 90 m and didn't spill into SDV. A relatively lower OIS6 lake level (<46 m OIS2) is consistent with our current understanding of the regional paleohydrology. During the OIS6 lake phase, the Amargosa River terminated in Lake Tecopa, and major flow into Death Valley was perhaps limited to spillover from the Owens-Searles- Panamint lake chain. During the OIS2 lake phase, both the Amargosa and Mojave rivers flowed into Death Valley.

Caskey, S.; Lackey, H. G.; Klinger, R. E.; Wan, E.; Sarna-Wojcicki, A.

2006-12-01

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

The Central Valley Hydrologic Model  

Microsoft Academic Search

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

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

2009-01-01

6

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

7

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.

8

Surficial Geologic Map of the Death Valley Junction 30' x 60' Quadrangle, California and Nevada  

USGS Publications Warehouse

This surficial geologic map of the Death Valley Junction 30' x 60' quadrangle was compiled digitally at 1:100,000 scale. 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. Shaded relief delineates the topography and appears as gray tones in the mountain ranges where the bedrock is undifferentiated and depicted as a single unit.

Slate, Janet L.; Berry, Margaret E.; Menges, Christopher M.

2009-01-01

9

Death Valley research revises age of last deep lake  

Microsoft Academic Search

The last deep lake in Death Valley probably existed during marine isotope stage VI, more than 100,000 years earlier than previously thought, according to a paper presented this past spring at a conference on geologic research in Death Valley. The long accepted paradigm of a deep lake, known as Lake Manley in the very late Pleistocene appears to have fallen

Michael N. Machette; Ren A. Thompson; Janet L. Slate; Bruce Heise

1999-01-01

10

Imaging Radar Applications in the Death Valley Region.  

National Technical Information Service (NTIS)

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 insi...

T. G. Farr

1996-01-01

11

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

12

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...

13

Technology push, market pull, and the Valley of Death  

NASA Astrophysics Data System (ADS)

The Valley of Death is the gap between fundamental research and product development, where apparently promising technologies can stall or disappear. Fundamental researchers may hope for potential applications of their work, and they try to push technology based on their research. Businesses may hope that new technology might serve their market needs, and they try to find promising new technologies that can be pulled toward practical use. The valley between the researchers and the businesses can be surprisingly twisted and thorny, despite government attempts to build roads across it. The histories of cryogenic engineering in the late 20th century and of thermoacoustics work at Los Alamos offer examples of both useful and misguided strategies in this valley. Although global thermoacoustics R&D has not (yet?) been as successful as cryogenic engineering, thermoacoustics has thus far avoided some of the worst pitfalls in the valley.

Swift, Gregory W.

2005-09-01

14

Death Valley research revises age of last deep lake  

NASA Astrophysics Data System (ADS)

The last deep lake in Death Valley probably existed during marine isotope stage VI, more than 100,000 years earlier than previously thought, according to a paper presented this past spring at a conference on geologic research in Death Valley. The long accepted paradigm of a deep lake, known as Lake Manley in the very late Pleistocene appears to have fallen in light of recent U-series dating of high shorelines.This and other new research were the topics of an interdisciplinary meeting on the “Status of Geologic Research and Mapping in Death Valley National Park.” As its title indicates, the conference was organized to compile up-to-date information on the status of geologic research and mapping in Death Valley National Park and surrounding areas. It also was intended to establish a network of active researchers to create synergy for cooperative, interdisciplinary research endeavors and to present recent and current research results in an informal setting, thus encouraging dialogue.

Machette, Michael N.; Thompson, Ren A.; Slate, Janet L.; Heise, Bruce

15

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

National Technical Information Service (NTIS)

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 ...

C. C. Faunt

1997-01-01

16

Upper Neogene stratigraphy and tectonics of Death Valley — a review  

NASA Astrophysics Data System (ADS)

New tephrochronologic, soil-stratigraphic and radiometric-dating studies over the last 10 years have generated a robust numerical stratigraphy for Upper Neogene sedimentary deposits throughout Death Valley. Critical to this improved stratigraphy are correlated or radiometrically-dated tephra beds and tuffs that range in age from > 3.58 Ma to < 1.1 ka. These tephra beds and tuffs establish relations among the Upper Pliocene to Middle Pleistocene sedimentary deposits at Furnace Creek basin, Nova basin, Ubehebe-Lake Rogers basin, Copper Canyon, Artists Drive, Kit Fox Hills, and Confidence Hills. New geologic formations have been described in the Confidence Hills and at Mormon Point. This new geochronology also establishes maximum and minimum ages for Quaternary alluvial fans and Lake Manly deposits. Facies associated with the tephra beds show that ˜3.3 Ma the Furnace Creek basin was a northwest-southeast-trending lake flanked by alluvial fans. This paleolake extended from the Furnace Creek to Ubehebe. Based on the new stratigraphy, the Death Valley fault system can be divided into four main fault zones: the dextral, Quaternary-age Northern Death Valley fault zone; the dextral, pre-Quaternary Furnace Creek fault zone; the oblique-normal Black Mountains fault zone; and the dextral Southern Death Valley fault zone. Post - 3.3 Ma geometric, structural, and kinematic changes in the Black Mountains and Towne Pass fault zones led to the break up of Furnace Creek basin and uplift of the Copper Canyon and Nova basins. Internal kinematics of northern Death Valley are interpreted as either rotation of blocks or normal slip along the northeast-southwest-trending Towne Pass and Tin Mountain fault zones within the Eastern California shear zone.

Knott, J. R.; Sarna-Wojcicki, A. M.; Machette, M. N.; Klinger, R. E.

2005-12-01

17

Relative size of fluvial and glaciated valleys in central Idaho  

Microsoft Academic Search

Quantitative comparisons of the morphometry of glaciated and fluvial valleys in central Idaho were used to investigate the differences in valley relief and width in otherwise similar geologic and geomorphic settings. The local relief, width, and cross-sectional area of valleys were measured using GIS software to extract information from USGS digital elevation models. Hillslope gradients were also measured using GIS

Byron E. Amerson; David R. Montgomery; Grant Meyer

2008-01-01

18

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

19

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

Microsoft Academic Search

Sedimentary and petrographic features of evaporites and associated sediments from a 185 m deep core taken in Death Valley, CA, together with uranium-series dating have been used to reconstruct the history of water table fluctuations and climate changes in Death Valley for the past 100 ka. Death Valley has been arid during the Holocene (0–10 ka), with predominantly mudflat and

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

1996-01-01

20

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

21

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

2013-02-09

22

Groundwater Availability of the Central Valley Aquifer, California  

USGS Publications Warehouse

California's Central Valley covers about 20,000 square miles and is one of the most productive agricultural regions in the world. More than 250 different crops are grown in the Central Valley with an estimated value of $17 billion per year. This irrigated agriculture relies heavily on surface-water diversions and groundwater pumpage. Approximately one-sixth of the Nation's irrigated land is in the Central Valley, and about one-fifth of the Nation's groundwater demand is supplied from its aquifers. The Central Valley also is rapidly becoming an important area for California's expanding urban population. Since 1980, the population of the Central Valley has nearly doubled from 2 million to 3.8 million people. The Census Bureau projects that the Central Valley's population will increase to 6 million people by 2020. This surge in population has increased the competition for water resources within the Central Valley and statewide, which likely will be exacerbated by anticipated reductions in deliveries of Colorado River water to southern California. In response to this competition for water, a number of water-related issues have gained prominence: conservation of agricultural land, conjunctive use, artificial recharge, hydrologic implications of land-use change, and effects of climate variability. To provide information to stakeholders addressing these issues, the USGS Groundwater Resources Program made a detailed assessment of groundwater availability of the Central Valley aquifer system, that includes: (1) the present status of groundwater resources; (2) how these resources have changed over time; and (3) tools to assess system responses to stresses from future human uses and climate variability and change. This effort builds on previous investigations, such as the USGS Central Valley Regional Aquifer System and Analysis (CV-RASA) project and several other groundwater studies in the Valley completed by Federal, State and local agencies at differing scales. The principal product of this new assessment is a tool referred to as the Central Valley Hydrologic Model (CVHM) that accounts for integrated, variable water supply and demand, and simulates surface-water and groundwater-flow across the entire Central Valley system. The development of the CVHM comprised four major elements: (1) a comprehensive Geographic Information System (GIS) to compile, analyze and visualize data; (2) a texture model to characterize the aquifer system;(3) estimates of water-budget components by numerically modeling the hydrologic system with the Farm Process (FMP); and (4) simulations to assess and quantify hydrologic conditions.

Faunt, Claudia C. (editor)

2009-01-01

23

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

24

Central Valley Emergency Medical Services System Development Program.  

National Technical Information Service (NTIS)

The Central Valley Emergency Medical Services System Development Program was established via a grant from Regional Medical Programs. Initially, research was undertaken by program staff to gather information - educational and operational - concerning pre-h...

L. H. Grayson L. B. Burnett M. A. Collins

1975-01-01

25

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.

26

Testing the Interbasin Flow Hypothesis at Death Valley, California  

NASA Astrophysics Data System (ADS)

Interbasin flow is a process by which groundwater moves from one topographic basin to another through an intervening structural or topographic barrier. For decades, interbasin flow has been the prevailing conceptual paradigm for groundwater movement in the arid southwestern United States wherever carbonate rocks are thought to be in continuous contact. This conceptual model of groundwater flow is especially relevant in the Death Valley region where water resources are scarce and where the U.S. government has conducted underground nuclear tests as well as the planned storage facility for spent nuclear fuel at Yucca Mountain, Nevada. Recent studies of large flux springs (~10,000 L/min) in the Furnace Creek area of Death Valley, California (Figure 1), however, indicate that the concept of interbasin flow may be fundamentally flawed, or at least not as universally applicable as previously thought. Rather, it appears that aquifers supplying Furnace Creek springs were replenished locally during episodes of wet climate more than 9500 yr ago, a contention supported by extensive regional fossil spring deposits.

Nelson, Stephen T.; Anderson, Katherine; Mayo, Alan L.

2004-09-01

27

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

Microsoft Academic Search

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

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

2010-01-01

28

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

Microsoft Academic Search

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

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

2008-01-01

29

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

30

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

31

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

NASA Astrophysics Data System (ADS)

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

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

32

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

33

Geostatistical estimates of future recharge for the Death Valley region  

SciTech Connect

Spatially distributed estimates of regional ground water recharge rates under both current and potential future climates are needed to evaluate a potential geologic repository for high-level nuclear waste at Yucca Mountain, Nevada, which is located within the Death Valley ground-water region (DVGWR). Determining the spatial distribution of recharge is important for regional saturated-zone ground-water flow models. In the southern Nevada region, the Maxey-Eakin method has been used for estimating recharge based on average annual precipitation. Although this method does not directly account for a variety of location-specific factors which control recharge (such as bedrock permeability, soil cover, and net radiation), precipitation is the primary factor that controls in the region. Estimates of recharge obtained by using the Maxey-Eakin method are comparable to estimates of recharge obtained by using chloride balance studies. The authors consider the Maxey-Eakin approach as a relatively simple method of obtaining preliminary estimates of recharge on a regional scale.

Hevesi, J.A. [Geological Survey, Las Vegas, NV (United States); Flint, A.L. [Geological Survey, Sacramento, CA (United States)

1998-12-01

34

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

SciTech Connect

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

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

1993-04-01

35

Application of Multispectral Radar and Landsat Imagery to Geologic Mapping in Death Valley.  

National Technical Information Service (NTIS)

Side-Looking Airborne Radar (SLAR) images, acquired by JPL and Strategic Air Command Systems, and visible and near-infrared LANDSAT imagery were applied to studies of the Quatenary alluvial and evaporite deposits in Death Valley, California. Unprocessed r...

M. Daily C. Elachi T. Farr W. Stromberg S. Williams

1978-01-01

36

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

Microsoft Academic Search

Gravity investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15'

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

2002-01-01

37

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

SciTech Connect

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

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

2003-04-21

38

Evolution of extensional basins and Basin and Range topography west of Death Valley, California  

NASA Astrophysics Data System (ADS)

Neogene extension in the Death Valley region, SE California, has produced a variety of sedimentary basins. Diachronous movements on an array of strike-slip and normal fault systems have resulted in the uplift and preservation of older basins in modern ranges. One of the best exposed of these is the Nova basin on the western flank of the Panamint Mountains. The Nova basin includes over 2000 m of sedimentary and volcanic rocks deposited during denudation of the Panamint Mountains metamorphic core complex in late Miocene (?) - early Pliocene time. The principal growth structure for the basin was the Emigrant detachment, which initiated and moved at a low angle. Modern Panamint Valley, west of the range, developed as a consequence of Late Pliocene - Recent, kinematically linked movement on the right-slip, high-angle Hunter Mountain fault zone and the low-angle Panamint Valley detachment. Detailed mapping of the intersection between the Emigrant and Panamint Valley detachments demonstrates that segments of the earlier system remained active during development of Panamint Valley and, thus, during development of modern Basin and Range topography as well. These results indicate that large-scale extension in the Death Valley region, accommodated by movement on low- to moderate-angle normal fault systems and high-angle strike-slip fault systems, is a continuing process. Basin and Range topography in the Panamint Valley - Death Valley area was generated at least in part by displacements on low-angle detachments rather than high-angle normal faults.

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

1989-06-01

39

Parasitology survey in the Palu Valley, central Sulawesi (Celebes), Indonesia.  

PubMed

A survey was undertaken in the Palu Valley, Central Sulasesi to determine whether schisto somiasis japonica was endemic in the area and to determine the prevalences rates of intestinal and blood parasites. Seven villages along the Palu River drainage system with an estimated popualtion of 18,700 were surveyed and 2,433 stools, 3,651 blood smears and 1,167 sera were collected and examined. PMID:176737

Cross, J H; Clarke, M D; Carney, W P; Putrali, J; Joesoef, A; Sajidiman, H; Partono, F; Hudojo; Oemijati, S

1975-09-01

40

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

41

Evolution of a forearc basin, Luzon central valley, Philippines  

SciTech Connect

The Cenozoic history of the 14 km-thick Luzon Central Valley sequence illustrates the development of a forearc basin. Forearc basins are important both as major sediment traps and as sites of hydrocarbon accumulations. The Luzon basin is floored by oceanic crust on the seaward (western) side and older accreted terranes on the arc (eastern) side. Initial sedimentation on this oceanic crust occurred during early Tertiary northward translation and emplacement of the crust as an ophiolite along a strike-slip or oblique-slip zone. The basal sediments consist of pelagic limestones and thin ash layers overlain by sandy turbidites derived from uplift and progressive dissection of the opmolite. A sequence of arc-derived sediments at least 26,000 ft (8 km) thick was shed into the eastern (arc) side of the basin during late Paleogene to Quaternary convergence along the western margin of Luzon. By the middle Miocene, the Central Valley became a continuous, elongate basin fringed by extensive shelf deposits, along both the uplifted seaward and arc sides of the basin. Detritus shed from both flanks filled the subsiding basin and resulted in progressively shallower depths. Nonmarine deposition began in central portions of the basin in the Pliocene and migrated with time both north and south along the basin axis. Late Miocene to Holocene movement along the Philippine fault zone caused uplift and folding of adjacent parts of the basin. Exploration models for the Central Valley predict gasprone hydrocarbon generation in central portions of the basin at times that coincide with and postdate the formation of both structural and stratigraphic traps. Previous drilling in the basin has either been in areas with thermally immature source rocks or has failed to reach prospective intervals where thermal maturation is inferred. The hydrocarbon potential has not been determined adequately.

Bachman, S.B.; Lewis, S.D.; Schweller, W.J.

1983-07-01

42

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

43

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

Microsoft Academic Search

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 km² 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

C. C. Faunt; A. K. Turner

1997-01-01

44

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

SciTech Connect

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

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

1991-12-31

45

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

46

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

47

Development of a three-dimensional model of sedimentary texture in valley-fill deposits of Central Valley, California, USA  

Microsoft Academic Search

A three-dimensional (3D) texture model was developed to help characterize the aquifer system of Central Valley, California\\u000a (USA), for a groundwater flow model. The 52,000-km2 Central Valley aquifer system consists of heterogeneous valley-fill deposits. The texture model was developed by compiling\\u000a and analyzing approximately 8,500 drillers’ logs, describing lithologies up to 950 m below land surface. The lithologic descriptions\\u000a on the

Claudia C. Faunt; Kenneth Belitz; Randall T. Hanson

2010-01-01

48

Sedimentology, diagenesis, and stratigraphic occurrence of giant ooids in the Ediacaran Rainstorm Member, Johnnie Formation, Death Valley region, California  

Microsoft Academic Search

The Rainstorm Member of the late Neoproterozoic Johnnie Formation contains several distinctive features of possibly regional to global significance—the Johnnie Oolite, an incised valley with a carbonate breccia fill, and an enigmatic bed of giant ooids (the Rainstorm giant ooids). Although the Johnnie Oolite and the incised valley occur in most Johnnie Formation outcrops scattered throughout the Death Valley region,

Elizabeth J. Trower; John P. Grotzinger

2010-01-01

49

Contaminated fish consumption in California's Central Valley Delta.  

PubMed

Extensive mercury contamination and angler selection of the most contaminated fish species coincide in California's Central Valley. This has led to a policy conundrum: how to balance the economic and cultural impact of advising subsistence anglers to eat less fish with the economic cost of reducing the mercury concentrations in fish? State agencies with regulatory and other jurisdictional authority lack sufficient data and have no consistent approach to this problem. The present study focused on a critical and contentious region in California's Central Valley (the Sacramento-San Joaquin Rivers Delta) where mercury concentrations in fish and subsistence fishing rates are both high. Anglers and community members were surveyed for their fish preferences, rates of consumption, the ways that they receive health information, and basic demographic information. The rates of fish consumption for certain ethnicities were higher than the rates used by state agencies for planning pollution remediation. A broad range of ethnic groups were involved in catching and eating fish. The majority of anglers reported catching fish in order to feed to their families, including children and women of child-bearing age. There were varied preferences for receiving health information and no correlation between knowledge of fish contamination and rates of consumption. Calculated rates of mercury intake by subsistence anglers were well above the EPA reference dose. The findings here support a comprehensive policy strategy of involvement of the diverse communities in decision-making about education and clean-up and an official recognition of subsistence fishers in the region. PMID:20176346

Shilling, Fraser; White, Aubrey; Lippert, Lucas; Lubell, Mark

2010-02-21

50

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

Microsoft Academic Search

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

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

2008-01-01

51

Geological Study of Uranium Potential of the Kingston Peak Formation, Death Valley Region, California.  

National Technical Information Service (NTIS)

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak qu...

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

1980-01-01

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

Imaging the subsurface stratigraphy in the Ubehebe hydrovolcanic field (Death Valley, California) using ground penetrating radar  

Microsoft Academic Search

Ground penetrating radar (GPR) surveys were carried out to collect subsurface images of the basaltic base surge deposits in the Ubehebe hydrovolcanic field, Death Valley National Park, California. Antennae with frequencies of 50, 100 and 200 MHz were used. This technique allowed the collection of useful geologic data, for example, the lower stratigraphic boundary of the pyroclastic deposits can be

B. Cagnoli; J. K Russell

2000-01-01

54

SAR imagery applied to the monitoring of hyper-saline deposits: Death Valley example (CA)  

Microsoft Academic Search

The present study aims at understanding the influence of salinity on the dielectric constant of soils and then on the backscattering coefficients recorded by airborne\\/spaceborne SAR systems. Based on dielectric measurements performed over hyper-saline deposits in Death Valley (CA), as well as laboratory electromagnetic characterization of salts and water mixtures, we used the dielectric constants as input parameters of analytical

Yannick Lasne; Philippe Paillou; Anthony Freeman; Bruce Chapman

2009-01-01

55

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

National Technical Information Service (NTIS)

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 flig...

L. Johnson

2009-01-01

56

Aerial Radiometric and Magnetic Survey: Death Valley National Topographic Map, Nevada, California.  

National Technical Information Service (NTIS)

The results of analysis of the airborne gamma radiation survey flown for the region identified as the Death Valley National Topographic Map NJ11-11 is presented in the bound Volume of this report. The airborne data gathered are reduced by ground computer ...

1979-01-01

57

Hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques.  

National Technical Information Service (NTIS)

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 bord...

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

1997-01-01

58

Macropolygon morphology, development, and classification on North Panamint and Eureka playas, Death Valley National Park CA  

Microsoft Academic Search

Panamint and Eureka playas, both located within Death Valley National Park, exhibit a host of surficial features including fissures, pits, mounds, and plant-covered ridges, representing topographic highs and lows that vary up to 2 m of relief from the playa surface. Aerial photographs reveal that these linear strands often converge to form polygons, ranging in length from several meters to

Paula Messina; Phil Stoffer; Ward C. Smith

2005-01-01

59

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

Microsoft Academic Search

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

James K. Crowley; Simon J. Hook

1996-01-01

60

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

61

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

Microsoft Academic Search

The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak quadrangles. Radiometric suveys of the area were conducted using gamma ray spectrometers. Samples of the conglomerate were

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

1980-01-01

62

Integrated Geophysical and Geologic Mapping of the Death Valley Region, California and Nevada  

Microsoft Academic Search

We use a combination of geophysical and geologic mapping approaches to produce an updated tectonic analysis of the Death Valley region, California and Nevada. Gravity and magnetic anomalies delineate discrete crustal blocks underlying basins and ranges of the region. High-resolution aeromagnetic surveys flown in 1999 and 2000, when processed to emphasize shallow magnetic sources, show clear evidence of mapped and

C. J. Fridrich; R. J. Blakely; J. B. Workman; R. A. Thompson; V. E. Langenheim

2001-01-01

63

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

Microsoft Academic Search

We have mapped alluvial fans in Death Valley, California using NASA's 8-12 mum six-channel airborne Thermal Infrared Multispecrtral Scanner (TIMS). We are able to recognize both composition and relative age differences. Age unit boundaries are generally consistent with those obtained by conventional mapping. Composition was verified by field investigatin and comparison with existing geologic maps. Bedrock and its young derived

Alan R. Gillespie; Anne B. Kahle; Frank D. Palluconi

1984-01-01

64

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

Microsoft Academic Search

We have mapped alluvial fans in Death Valley, California using NASA's 8-12 µm six-channel airborne Thermal Infrared Multispectral Scanner (TIMS). We are able to recognize both composition and relative age differences. Age unit boundaries 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

Alan R. Gillespie; Anne B. Kahle; Frank D. Palluconi

1984-01-01

65

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

Microsoft Academic Search

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

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

1987-01-01

66

Study of burn deaths in Nagpur, Central India  

Microsoft Academic Search

A series of 384 victims of burn deaths were reviewed to determine the trends of burn deaths in Nagpur, an urban area of Central India. It was found that deaths due to burning accounted for 21.6% of the total medicolegal deaths. Female (74.2%) predominance was seen in burning with male–female ratio equal to 1:2.9. Most of the victims of burn

Vipul Namdeorao Ambade; Hemant Vasant Godbole

2006-01-01

67

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 long-term effects of groundwater development and irrigation-supported agriculture on water quality in arid and semiarid regions around the world. Journal compilation ?? 2009 National Ground Water Association. No claim to original US government works.

Jurgens, B. C.; Fram, M. S.; Belitz, K.; Burow, K. R.; Landon, M. K.

2010-01-01

68

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

69

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

70

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

71

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

Microsoft Academic Search

This aeromagnetic map of the Death Valley ground-water model area was prepared from numerous separate aeromagnetic surveys that were gridded, merged, and described by Hildenbrand and Kucks (1988) and by McCafferty and Grauch (1997). These data are available in grid format from the EROS Data Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, and from the National Geophysical Data

D. A. Ponce; R. J. Blakely

2002-01-01

72

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

Microsoft Academic Search

The locations of principal faults and structural zones that may influence ground-water flow were compiled in support of a three-dimensional ground-water model for the Death Valley regional flow system, which covers 80,000 km2 in southwestern Nevada and southeastern California. Faults include Neogene extensional and strike-slip faults and pre-Tertiary thrust faults. Emphasis was given to characteristics of faults and deformed zones

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

2002-01-01

73

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

Microsoft Academic Search

The purpose of this map is to provide tectonic interpretations in the Death Valley ground-water model area to be incorporated into a transient ground-water flow model by the U.S. Geological Survey (D'Agnese, 2000; D'Agnese and Faunt, 1999; Faunt and others, 1999; and O'Brien and others, 1999). This work has been conducted in collaboration with the U.S. Department of Energy in

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

2002-01-01

74

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

Microsoft Academic Search

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

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

2003-01-01

75

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; Roberts, S.M. [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; Yang, W. [State Univ. of New York, Stony Brook, NY (United States). Marine Science Research Center

1999-01-01

76

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

SciTech Connect

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

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

2002-03-12

77

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

National Technical Information Service (NTIS)

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, r...

F. A. D'Agnese G. M. O'Brien C. C. Faunt C. A. San Juan

1999-01-01

78

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

NASA Astrophysics Data System (ADS)

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

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

79

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

Microsoft Academic Search

This map shows the depth to pre-Cenozoic basement in the Death Valley ground-water model area. It was prepared utilizing gravity (Ponce and others, 2001), geologic (Jennings and others, 1977; Stewart and Carlson, 1978), and drill-hole information. Geophysical investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S.

R. J. Blakely; D. A. Ponce

2002-01-01

80

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

81

Diurnal Evolution of Three-Dimensional Wind and Temperature Structure in California's Central Valley  

SciTech Connect

The diurnal evolution of the three-dimensional summer season mean wind and temperature structure in California’s Sacramento and San Joaquin Valleys (collectively called the Central Valley) are investigated using data from 22 radar wind profiler/Radio Acoustic Sounding Systems (RASS) operated as part of the Central California Ozone Study in 2000. The profiler network revealed, for the first time, that the persistent summer season flow pattern documented by surface observations extends 800-1000 m above the surface. At most locations, up-valley winds persist both day and night except at the upper ends of the valleys and close to the valley sidewalls where diurnal wind reversals occur. Wind speeds exhibit pronounced diurnal oscillations, with amplitudes decreasing with height. A low-level wind maximum occurs in the lowest 300 m, with a sharp decrease in speed above the maximum. Especially well-defined nocturnal low-level jets occur at sites in the southern San Joaquin Valley, where maximum speeds of 10 m s-1 or more occur 1-2 h before midnight at heights near 300 m. The afternoon mixed layer, generally deeper than 1000 m, increases in depth with up-valley distance in both valleys. At night, temperature inversions develop in the lowest several hundred meters with near-isothermal layers above. Mean temperatures in the lowest 500 m of the valleys are always warmer than at the same altitude over the coast, and temperature increases from the lower to upper valleys. The diurnal oscillation of the coast-valley and along-valley temperature and pressure difference reach a maximum in late afternoon and a minimum in early morning. These oscillations are in phase with the diurnal variation of westerly onshore flows. The along-valley wind maxima, however, occur 1-2 h before midnight while the pressure gradient maxima are usually found just before sunset.

Zhong, Shiyuan; Whiteman, Charles D.; Bian, Xindi

2004-11-01

82

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

USGS Publications Warehouse

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

Stauffer, Karl W.

1975-01-01

83

Evaluation of Central Valley Project Water Supply and Delivery Systems. Global Climate Change Response Program.  

National Technical Information Service (NTIS)

A simple mass balance reservoir operation model for the Central Valley Project (CVP) and State Water Project (SWP) water systems, California, was used to assess the possible global climate change impacts to the CVP. Historic hydrologic parameters were mod...

J. Sandberg P. Manza

1991-01-01

84

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

Federal Register 2010, 2011, 2012, 2013

...District. City of Santa Barbara. Tulare Irrigation District. Pacheco Irrigation District. City of Tracy. Citrus Heights. Water District. To meet the requirements of the Central Valley Project Improvement Act of 1992 (CVPIA) and the...

2012-06-05

85

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

EPA Science Inventory

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

86

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

87

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

88

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

89

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

90

Integrated Geophysical and Geologic Mapping of the Death Valley Region, California and Nevada  

NASA Astrophysics Data System (ADS)

We use a combination of geophysical and geologic mapping approaches to produce an updated tectonic analysis of the Death Valley region, California and Nevada. Gravity and magnetic anomalies delineate discrete crustal blocks underlying basins and ranges of the region. High-resolution aeromagnetic surveys flown in 1999 and 2000, when processed to emphasize shallow magnetic sources, show clear evidence of mapped and unmapped faults, including specific strands of the Furnace Creek, Death Valley, and Stateline fault zones. Depth to pre-Tertiary basement, derived by inverting isostatic residual gravity anomalies, indicate basin-bounding faults and the sub-surface extent of deep sub-basins. Taken together, faults interpreted from aeromagnetic anomalies and basins interpreted from gravity inversion define a distinctive pattern of northwest-striking strike-slip faults and north-striking transtensional basins and basin-bounding normal faults. Surface geologic mapping constrains the nature of many of the largely concealed structures imaged in the gravity and aeromagnetic surveys. Many geophysical lineaments project locally up onto bedrock, where the cause can be directly observed. In other cases, changes in stratigraphy or metamorphic grade or other evidence of displacements across geophysically defined structures provide critical clues as to cause. Overlapping basinal structures produced in multiple tectonic episodes can be unraveled in some cases by combining structure mapping with stratigraphic constraints on the tectonic evolution of this region. For example, a north-northeast-trending gravity anomaly under Yucca Mountain appears to define an old basin boundary that formed by ~16 Ma, was abandoned at ~13 Ma, and may be correlative with an exposed growth fault on the northeast flank of the Funeral Mountains. Our synthesis of the latest field-based studies and potential-field investigations is summarized in an interpretive tectonic map of the Death Valley region.

Fridrich, C. J.; Blakely, R. J.; Workman, J. B.; Thompson, R. A.; Langenheim, V. E.

2001-12-01

91

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

92

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

SciTech Connect

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

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

2002-03-12

93

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)

1996-08-01

94

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

SciTech Connect

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

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

1980-09-01

95

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

NASA Astrophysics Data System (ADS)

We have mapped alluvial fans in Death Valley, California using NASA's 8-12 µm six-channel airborne Thermal Infrared Multispectral Scanner (TIMS). We are able to recognize both composition and relative age differences. Age unit boundaries 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, Alan R.; Kahle, Anne B.; Palluconi, Frank D.

96

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

PubMed Central

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

Adams, David J.

2012-01-01

97

Geology: Structural history and fluvial geomorphology of the southern Death Valley Fault Zone, Inyo and San Bernardino Counties, California  

NASA Astrophysics Data System (ADS)

Estimates of offset along the southern Death Valley fault zone range from 8 to 80 km of right-lateral slip. In order to determine the amount of offset, an area of approximately 200 square km was mapped in southern Death Valley between the Owishead Mountains and the southern Black Mountains, focusing primarily on late-cenozoic deposits. Field mapping was supplemented by age determinations of volcanic rocks and geophysical studies, including a gravity and magnetic line across the fault zone and paleomagnetic determinations to assist in correlation and age control of lacustrine deposits. By matching offset alluvial fan gravel with its source area, 20 to 35 km of right-lateral slip is documented for the last 10 to 12 million years. The geometry of the pull-apart-basin model that has been proposed for Death Valley requires that there be approximately 20 km of right-lateral slip along the southern Death Valley fault zone. Virtually all of the right-lateral slip took place prior to 0.9 million years ago along western traces of the southern Death Valley fault zone.

Butler, P. R.

98

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

99

Paeloredox Conditions During Deposition of Neoproterozoic Low Latitude Glacial Strata of the Death Valley Region, CA  

NASA Astrophysics Data System (ADS)

Considerable debate surrounds the extent of late Neoproterozoic glaciations and their effect on ocean circulation, chemistry, and the evolution of life. Glacially interpreted diamictites are associated with banded iron formations suggesting the existence of a reduced ocean possibly caused by ice blocking ocean water- atmosphere oxygen exchange. However, differences in the stratigraphic position of the banded iron formations relative to the diamictite complicate their interpretation as indicators of widespread reducing conditions during deposition. To date little other evidence has been reported to substantiate the extent of ocean circulation or to examine the link between productivity, decomposition and the generation of reducing conditions. This work examines the geochemistry of two Neoproterozoic outcrops containing diamictite/cap carbonate pairs in Death Valley, CA to better understand their depositional environments. Paleoredox conditions are inferred from trace element concentrations and speciation. Geochemical evidence from the Death Valley sedimentary record does not support the existence of anoxic or euxinic ocean conditions during deposition. Neither the Marinoan diamictite nor the associated cap carbonate sequences show a major enrichment in trace metals. Minor enrichment in uranium and vanadium concentrations is seen at the diamictite/carbonate boundary and suggests that ocean conditions may have been mildly suboxic immediately following glaciation. Thus, these data indicate that the ocean basin experienced significant mixing and ocean-atmosphere gas exchange during and after glaciation.

Meyer, E. E.; Bostick, B. C.; Landis, J. D.; Quicksall, A. N.; Theissen, K. M.

2006-12-01

100

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

101

Macropolygon morphology, development, and classification on North Panamint and Eureka playas, Death Valley National Park CA  

NASA Astrophysics Data System (ADS)

Panamint and Eureka playas, both located within Death Valley National Park, exhibit a host of surficial features including fissures, pits, mounds, and plant-covered ridges, representing topographic highs and lows that vary up to 2 m of relief from the playa surface. Aerial photographs reveal that these linear strands often converge to form polygons, ranging in length from several meters to nearly a kilometer. These features stand out in generally dark contrast to the brighter intervening expanse of flat, plant-free, desiccated mud of the typical playa surface. Ground-truth mapping of playa features with differential GPS (Global Positioning System) was conducted in 1999 (North Panamint Valley) and 2002 (Eureka Valley). High-resolution digital maps reveal that both playas possess macropolygons of similar scale and geometry, and that fissures may be categorized into one of two genetic groups: (1) shore-parallel or playa-interior desiccation and shrinkage; and (2) tectonic-induced cracks. Early investigations of these features in Eureka Valley concluded that their origin may have been related to agricultural activity by paleo-Indian communities. Although human artifacts are abundant at each locale, there is no evidence to support the inference that surface features reported on Eureka Playa are anthropogenic in origin. Our assumptions into the genesis of polygons on playas is based on our fortuitous experience of witnessing a fissure in the process of formation on Panamint Playa after a flash flood (May 1999); our observations revealed a paradox that saturation of the upper playa crusts contributes to the establishment of some desiccation features. Follow-up visits to the same feature over 2 yrs' time are a foundation for insight into the evolution and possible longevity of these features.

Messina, Paula; Stoffer, Phil; Smith, Ward C.

2005-12-01

102

Contractional Strain Related to Interference of Intersecting Sets of Strike-slip Faults in the Southern Death Valley Region, California  

NASA Astrophysics Data System (ADS)

Structural and geomorphic data reveal complex neotectonic deformation(Pliocene-Quaternary, post 3-4 Ma)derived in part from interactions among intersecting sets of strike-slip faults in the southern Death Valley area on the eastern margin of the Eastern California Shear Zone. A distinct 40-km-wide domain of strike-slip faulting and associated contractional strain is bounded on the north by the southern end of the Panamint and Death Valley extensional terrane and on the south by the eastern Garlock fault (EGF). The dominant regional structures are (a) two NW-trending dextral-slip faults—the southern Death Valley fault (SDVF) and southern Panamint Valley fault (SPVF), and (b) three E- to NE-oriented sinistral-slip faults. This latter set includes the EGF, an associated splay of the Owl Lake fault (OLF) and a diffuse fault zone associated with discontinuous surface rupture in upper and central Wingate Wash valley (WWF). The strike-slip faults intersect with one another in a complex interference pattern that produces on-fault zones of transpressive deformation. These faults, moreover, are embedded within widespread areas of off-fault contractional strain in the intervening crustal blocks. Specifically, secondary on-fault transpressive deformation occurs along the majority of the EGF and SDVF and sections of the OLF and SPVF. This transpression is manifested as commonly asymmetric flower structures that produce domal to elongate zones of uplifted topography along the fault trace. Surface deformation within the flower structure appears partitioned between (a)translation along strike-slip faults in the dissected core of the uplifts and (b) contraction and uplift accommodated on near-surface blind thrusts below fault-propagation folds on the flanks of the structure. Where two or more large strike-slip faults intersect one another, one or more of the structures typically merges with or is truncated against one primary though-going structure. The geometry and slip-sense of the through-going structure commonly is altered at this intersection by development of an arcuate bend in the fault trace and (or) enhancement of any reverse-slip component. In the most extreme case, the EGF terminates in the Avawatz Mts. behind the apparent SE-continuation of the SDVF. This structure is characterized in the area of intersection by a stacked set of blind to emergent thrust faults and associated fault-propagation folds bounding a prominent NE-oriented arcuate salient in the range- front. The intersections of faults with opposing slip sense are additionally surrounded by broad aureoles of off- fault uplift and (or) tilting that induce significant bedrock incision and drainage rearrangement. Many crustal blocks between intersecting faults are internally deformed by contractional structures ranging from localized strain on folds and pop-up structures to broad linear zones of synformal downwarping and antiformal uplift. For example, the Owlshead Mts. block (OMB) has experienced complex contractional deformation on both boundary and internal fault and fold structures. This deformation in part is derived from mutual interference between intersecting sets of dextral faults (SDVF and SPV) and sinistral faults (WWF and EGF) that completely bound the block. Further, the entire OMB may have been laterally extruded to the northeast above a blind thrust system, thereby producing a distinct transpressive right-step or kink to the northeast in the SDVF, which bounds the block on that side.

Menges, C. M.; Pavlis, T. L.; McMackin, M. R.; Serpa, L.

2006-12-01

103

Development of a three-dimensional model of sedimentary texture in valley-fill deposits of Central Valley, California, USA  

NASA Astrophysics Data System (ADS)

A three-dimensional (3D) texture model was developed to help characterize the aquifer system of Central Valley, California (USA), for a groundwater flow model. The 52,000-km2 Central Valley aquifer system consists of heterogeneous valley-fill deposits. The texture model was developed by compiling and analyzing approximately 8,500 drillers’ logs, describing lithologies up to 950 m below land surface. The lithologic descriptions on the logs were simplified into a binary classification of coarse- and fine-grained. The percentage of coarse-grained sediment, or texture, was then computed for each 15-m depth interval. The model was developed by 3D kriging of the percentage of coarse-grained deposits onto a 1.6-km spatial grid at 15-m depth intervals from land surface down to 700 m below land surface. The texture model reflects the known regional, spatial, and vertical heterogeneity in the aquifer system. The texture model correlates to sediment source areas, independently mapped geomorphic provinces, and factors affecting the development of alluvial fans, thus demonstrating the utility of using tcdrillers’ logs as a source of lithologic information. The texture model is upscaled to a layered groundwater flow model for use in defining the hydraulic properties of the aquifer system.

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

2010-05-01

104

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

SciTech Connect

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

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

2002-03-12

105

Assessing vertical axis rotations in large-magnitude extensional settings: A transect across the Death Valley extended terrane, California  

NASA Astrophysics Data System (ADS)

Models for Neogene crustal deformation in the central Death Valley extended terrane, southeastern California, differ markedly in their estimates of upper crustal extension versus shear translations. Documentation of vertical axis rotations of range-scale crustal blocks (or parts thereof) is critical when attempting to reconstruct this highly extended region. To better define the magnitude, aerial extent, and timing of vertical axis rotation that could mark shear translation of the crust in this area, paleomagnetic data were obtained from Tertiary igneous and remagnetized Paleozoic carbonate rocks along a roughly east-west traverse parallel to about 36°N latitude. Sites were established in ˜7 to 5 Ma volcanic sequences (Greenwater Canyon and Brown's Peak) and the ˜10 Ma Chocolate Sundae Mountain granite in the Greenwater Range, ˜8.5 to 7.5 Ma and 5 to 4 Ma basalts on the east flank of the Black Mountains, the 10.6 Ma Little Chief stock and upper Miocene(?) basalts in the eastern Panamint Mountains, and Paleozoic Pogonip Group carbonate strata in the north central Panamint Mountains. At the site level, most materials yield readily interpretable paleomagnetic data. Group mean directions, after appropriate structural corrections, suggest no major vertical axis rotation of the Greenwater Range (e.g., D = 359°, I = 46°, ?95 = 8.0°, N = 12 (7 normal (N), 5 reversed (R) polarity sites)), little post-5 Ma rotation of the eastern Black Mountains (e.g., D = 006°, I = 61°, ?95 = 4.0°, N = 9 N, 6 R sites), and no significant post-10 Ma rotation of the Panamint Range (e.g., D = 181°, I = -51°, ?95 = 6.5°, N = 9 R sites). In situ data from the Greenwater Canyon volcanic rocks, Chocolate Sundae Mountain granite, Funeral Peak basalt rocks, the Little Chief stock, and Paleozoic carbonate rocks (remagnetized) are consistent with moderate south east-side-down tilting of the separate range blocks during northwest directed extension. The paleomagnetic data reported here suggest that the Panamints shared none of the 7 Ma to recent clockwise rotation of the Black Mountains crystalline core, as proposed in recent models for transtensional development of the central Death Valley extended terrane.

Petronis, Michael S.; Geissman, John W.; Holm, Daniel K.; Wernicke, Brian; Schauble, Edwin

2002-01-01

106

Beryllium-10 terrestrial cosmogenic nuclide surface exposure dating of Quaternary landforms in Death Valley  

NASA Astrophysics Data System (ADS)

Quaternary alluvial fans, and shorelines, spits and beach bars were dated using 10Be terrestrial cosmogenic nuclide (TCN) surface exposure methods in Death Valley. The 10Be TCN ages show considerable variance on individual surfaces. Samples collected in the active channels date from ~ 6 ka to ~ 93 ka, showing that there is significant 10Be TCN inheritance within cobbles and boulders. This suggests that the predominantly bedrock hillslopes erode very slowly and sediment is transferred very gradually in most regions within Death Valley. Comparisons of 10Be TCN ages on alluvial fan surfaces with chronostratigraphies based on soil development and optically stimulated luminescence dating show that minimum 10Be TCN ages within sample sets on individual surfaces most closely approximate to the age of landforms that are younger than ~ 70 ka. Alluvial fan surfaces older than ~ 70 ka have begun to undergo sufficient erosion such that the majority of 10Be TCN ages for datasets on individual surfaces probably underestimate the true age of the surface due to erosion and exhumation of fresh cobbles and boulders. The spread of 10Be TCN ages for beach bars near Beatty Junction and shorelines ~ 8 km south of Furnace Creek is large, ranging from ~ 119 ka to ~ 385 ka and ~ 109 ka to ~ 465 ka, respectively. New and previously published luminescence ages and soil development suggest that these landforms may have formed during marine isotope stage (MIS) 2 (~ 22-18 ka), but these younger ages may reflect elluviation of material into the bar deposit long after deposition, and hence the younger ages do not record the true antiquity of the landforms. This disparity between dates determined by different dating methods and the large spread of TCN ages suggests that the cobbles and boulders have considerable inherited 10Be concentrations, suggesting that the clasts have been derived from older shorelines or associated landforms. These results highlight the problems associated with using surface cobbles and boulders to date Quaternary surfaces in Death Valley and emphasizes the need to combine multiple, different dating methods to accurately date landforms in similar dryland regions elsewhere in the world. However, these results highlight the potential to use TCN methods, when used in combination with other dating techniques, to examine and quantify processes such as sediment transfer and denudation in drylands.

Owen, Lewis A.; Frankel, Kurt L.; Knott, Jeffrey R.; Reynhout, Scott; Finkel, Robert C.; Dolan, James F.; Lee, Jeffrey

2011-02-01

107

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

108

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

109

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

110

Devils Hole: A Window into the Carbonate Aquifer of the Death Valley Regional Flow System  

NASA Astrophysics Data System (ADS)

Devils Hole is a window into the carbonate aquifer located in the Amargosa Valley of southwestern Nevada, and is the sole habitat for the endangered Devils Hole pupfish (Cyprinodon diabolis). The water surface is 15 m below the land surface and approximately 50 m2 in area. This groundwater-fed pool has no surface inlet or outlet; the system is fed by water flowing through the carbonate aquifer of the Death Valley regional groundwater flow system. The system comprises a cavernous deep pool of unknown depth (divers have descended as far as 130 m) and a shallow breeding shelf (20 - 80 cm deep) that provides a substrate for pupfish spawning and algae growth. While water temperatures within the deep pool are relatively constant around 33.5° C, temperatures on the shallow shelf are highly variable, ranging from lows of 26° C during winter nights to highs of 37° C during summer. Seasonal convective mixing in the system is driven by air temperature changes, and diel convective mixing occurs when the water over the shallow shelf is exposed to direct sunlight during summer afternoons. These mixing processes expose both adult and juvenile pupfish to a variety of stresses, from food limitation to thermal extremes.

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

2010-12-01

111

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

112

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

113

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

114

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

115

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

116

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

SciTech Connect

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

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

1991-04-01

117

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

118

Interseismic deformation and geologic evolution of the Death Valley Fault Zone  

NASA Astrophysics Data System (ADS)

The Death Valley Fault Zone (DVFZ), located in southeastern California, is an active fault system with an evolved pull-apart basin that has been deforming over the past 6 Myr. We present a study of the interseismic motion and long-term stress accumulation rates to better understand the nature of both past and present-day loading conditions of the DVFZ. Using a 3-D semi-analytic viscoelastic deformation model, combined with geodetic velocities derived from the Mobile Array of GPS for Nevada Transtension (MAGNET) network and the Southern California Earthquake Center (SCEC) Crustal Motion Map version 4 (CMMv4) GPS data, we establish parameters for interseismic slip rate and apparent locking depth for four DVFZ fault segments. Our preferred model provides good fit to the data (1.0 mm/yr and 1.5 mm/yr RMS misfit in the fault-perpendicular and fault-parallel directions, respectively) and yields apparent locking depths between 9.8-17.1 km and strike-slip rates of 3-7 mm/yr for the segments. We also determine subsidence (0.5-0.8 mm/yr) and extension (1.0-1.2 mm/yr) rates in the pull-apart basin region. With these parameters, we construct a DVFZ evolution model for the last 6 Myr that recreates the motion of the fault blocks involved in the formation of the present-day geological structures in Death Valley. Finally, using Coulomb stress accumulation rates derived from our model (0.25-0.49 MPa/100 yr), combined with earthquake recurrence interval estimates of 500 to 2600 years, we assess present-day seismic hazards with calculated moment magnitudes ranging from 6.7-7.7.

Del Pardo, Cecilia; Smith-Konter, Bridget R.; Serpa, Laura F.; Kreemer, Corné; Blewitt, Geoffrey; Hammond, William C.

2012-06-01

119

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

SciTech Connect

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

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

2002-10-17

120

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

121

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

122

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

Microsoft Academic Search

Recharge estimates are needed to define the upper boundary conditions for groundwater flow models used to analyze water contamination and availability in the Death Valley region of southeastern California and southern Nevada. Estimated net infiltration, where net infiltration is defined as percolation below the root zone, was used as an indicator of potential recharge. Spatially distributed net infiltration was estimated

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

2001-01-01

123

Complete Bouguer gravity map of the Nevada part of the Death Valley 1° x 2° sheet  

Microsoft Academic Search

The complete Bouguer gravity map of the Nevada part of the Death Valley 1° x 2° sheet results from a compilation of gravity data obtained by field crews of the U.S. Geological Survey. The locations for the gravity stations and the gravity base stations are shown. Most of the gravity stations were obtained as part of the gravity survey of

D. L. Healey; R. R. Wahl; F. E. Currey; W. E. Stephens

1978-01-01

124

Airborne Laser Swath Mapping as a Tool to Study Active Deformation Along the Death Valley Fault Zone, California  

Microsoft Academic Search

The degree to which fault loading and strain release rates are constant in time and space is one of the most fundamental, unresolved issues in modern tectonics. In order to understand how strain is distributed across plate boundaries we must compare slip rate data over a wide range of time scales. The Death Valley fault zone (DVFZ) is one of

K. L. Frankel; J. F. Dolan; R. C. Finkel; T. Wasklewicz

2005-01-01

125

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

Microsoft Academic Search

All available instrumental winter precipitation data for the Central Valley of California back to 1850 were digitized and analyzed to construct continuous time series. Many of these data, in paper or microfilm format, extend prior to modern National Weather Service Cooperative Data Program and Historical Climate Network data, and were recorded by volunteer observers from networks such as the US

S. F. Dodds; C. J. Mock

2009-01-01

126

Epidemiology and Public Health Consequences of Methamphetamine Use in California's Central Valley  

Microsoft Academic Search

Methamphetamine use is an increasingly serious public health problem in California and other parts of the country. Despite sensationalistic media attention, however, very little is known about users of this clandestinely consumed drug. Employing methods known as Rapid Assessment and Response, the authors describe the epidemiology and public health implications of methamphetamine use in California's Central Valley, with a focus

David R. Gibson; Martin H. Leamon; Neil Flynn

2002-01-01

127

76 FR 127 - The Central Valley Project, the California-Oregon Transmission Project, the Pacific Alternating...  

Federal Register 2010, 2011, 2012, 2013

...Transmission Proposed Rate Schedule CV-T3 (Supersedes CV-T2) Central Valley Project...transmission rate under Rates Schedule CV-T3 is revised. Component 2: Any charges or...1, 2011. Proposed Rate Schedule COTP-T3 (Supersedes Schedule COTP-T2)...

2011-01-03

128

The population shuffle in the central Illinois valley: A diachronic model of Mississippian biocultural interactions  

Microsoft Academic Search

A new population genetics method is applied to discriminate between processes of extraregional gene flow and intraregional biological continuity within and among three temporally sequential prehistoric Native American cultures in the central Illinois valley. Within a population genetics framework, the impact of regional and interregional cultural changes on local population structure can be quantified and the magnitude of biocultural interaction

Dawnie Wolfe Steadman

1998-01-01

129

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

National Technical Information Service (NTIS)

This report assesses the state of the science on the environmental impacts of mountaintop mines and valley fills (MTM-VF) on streams in the Central Appalachian Coalfields. These coalfields cover about 48,000 square kilometers (12 million acres) in West Vi...

2001-01-01

130

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

SciTech Connect

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

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

1993-03-01

131

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

132

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

133

Pedodiversity and pedogenesis in Zayandeh-rud Valley, Central Iran  

NASA Astrophysics Data System (ADS)

A geomorphic hierarchical downscaling method was used to decompose the forms and processes forming the landscapes and their subdivisions in the main region of Zayandeh-rud Valley. The purpose of this study was to determine the degree of soil heterogeneity and to check if K-entropy would be a good measure of soil evolution. Soil diversity analyses were performed considering soil families as individuals of soil entities in each geomorphic or taxonomic category level. Pedodiversity indices were used to follow the trend of soil and landscape evolution. The relationships between K-entropy (Shannon diversity index) and pedo-richness versus increasing area were analyzed to find out the effects of soil-landscape evolution on complexity of soil patterns in different geomorphic surfaces. Entropy-age relationship was studied to check the pedogenetic pathways responsible for soil landscape evolution. The soil diversity increases as geomorphic and taxonomic hierarchy levels decrease. The diversity indices were high when the sequence of soil horizons in a homogeneous family was also investigated. An increase in K-entropy of soil and landscape during time confirms the hypothesis of soil divergence evolution, whereby differences in initial conditions or local perturbations, and dynamic instability appear to have produced more variable soils and landscapes in the study area.

Toomanian, Norair; Jalalian, Ahmad; Khademi, Hossein; Eghbal, Mostafa Karimian; Papritz, Andreas

2006-11-01

134

Role of volcanics in formation of new crust during hyperextension of the Death Valley region  

NASA Astrophysics Data System (ADS)

Death Valley (DV) is a pull-apart basin formed in the last 3 million years by extensional dextral strike slip linked to eastward propagation of the Pacific - North America plate boundary. From 15-18 Ma until 6 Ma, DV was part of the Basin and Range extensional province, with large-magnitude generally east-west extension. Several structural features in the region have been proposed as pinning points for restoration of this extension, allowing for quantitative palinspastic reconstructions. These reconstructions show over 100 km of motion between some pinning points. Depending on how initial geometries are restored, these offsets can imply over 200% extension. In a continental margin setting, this amount of extension would produce thin crust (assuming the horizontal extension factor equals the inverse of the crust thinning factor) and ultimately the mantle would probably be exhumed, like in the Iberia-Newfoundland rift. In the Death Valley region, however, the crust is still about 30 km thick. With 200% extension, original crustal thickness would have been nearly 90 km (defining %extension as {original-present}/original%, thickness or length). In this presentation I suggest that original crustal thickness was a more reasonable 40-45 km. 200% extension of this crust would have reduced crustal thickness to 15 km. Based on the observation of voluminous syn-extensional volcanics, both extrusive and intrusive, in the DV region, I also suggest that the difference in crustal thickness was made up of new volcanic material that has become a part of the crust during extension. The same hypothesis can be applied to the Basin and Range province, where syn-extensional volcanics make up nearly 50% of the exposed pre-Quaternary outcrop. These volcanics could have increased crustal thickness to the observed 30km, in spite of the large amount of extension in the province. Applying the same hypothesis to passive margins, where the presence or absence of syn-extensional volcanics is the primary differentiating factor in classification of margins, formation of new crust by volcanism is a major factor is the crustal structure of volcanic margins.

Norton, I. O.

2011-12-01

135

Stable Ca, H and O Isotopes in the Modern Death Valley Hydrological System, California  

NASA Astrophysics Data System (ADS)

We have characterized waters and sediment from Death Valley to investigate the fractionation of Ca isotopes and how it relates to evaporation effects and precipitation of Ca minerals in a natural system. The ultimate objective is to determine whether there can be substantial Ca isotope fractionation in the absence of significant biological activity, which would determine whether Ca isotopes could be useful as a biomarker on Mars. In this study, we collected water samples from the Death Valley region in May of 2006, and we have also data from a sediment core at Badwater. The ?18O and ?^{}D values of waters vary from -13.9 to +1.6 ‰ and from -109 to -21 ‰ respectively. The spring waters, discharged from the regional groundwater systems and collected at their sources, have low ?18O and ?^{}D values falling on the meteoric water line (MWL). Salt pan brines fall on the upper end of the local evaporation trend (Yang at al., 1997), indicating strong evaporation. The surface spring waters collected from small shallow ponds at the edges of the salt pans show significant variation from the MWL which are the result of evaporation and mixing with the concentrated salt pan brines. The ?44Ca values of the spring waters vary slightly from -0.39 to -0.25 ‰ regardless of their locations and types of water chemistry, which is close to the local bedrock values; whereas the ?44Ca values of the two concentrated Badwater salt pan brine samples are about +0.4 ‰. There is about 0.7 ‰ difference in ?44Ca between the evaporated brine-Ca (chloride-Ca) and the inflow source-Ca, which apparently results from the precipitation of calcium carbonate and sulfate during extreme evaporation. This effect is consistent with the precipitated Ca salts being enriched in the light Ca isotopes as is observed in laboratory precipitation experiments. Calcite and sulfate minerals from the 186-meter Badwater saline sediment core were also measured. The calcite is slightly lower in ?44Ca relative to the freshwater inflow, but shows no significant variation in the evaporation-dissolution-flooding cycles indicated by O and D isotopes, nor in glacial-interglacial climatic transitions (Yang et al., 2005). It is most likely that there is only about -0.3 ‰ differences in ?44Ca between the non-chloride minerals and their inflow sources; hence although there may be some inorganic isotopic fractionation, it does not appear to be as large as the ca. 1.3 permil fractionations found in laboratory experiments.

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

2006-12-01

136

Clustering Regional Ozone Concentrations to Reveal Meteorological Regimes Influencing Air Quality in California's Central Valley  

NASA Astrophysics Data System (ADS)

California's central valley suffers from serious ozone air pollution problems due to its unique geography as well as diverse emission sources from both local and upwind areas. The primary flows in the region are produced by the thermal contrast between the ocean and land, and between the valley and surrounding mountains. On typical summer days, westerly winds are funneled into the valley through gaps in the coastal range, along with the Bay area pollutants. During the day, the flow is directed up the Sierra Nevada Mountain slope, while at night it reverses and recirculates the local pollutants. Meteorological factors are important in governing the spatial distribution and variation of air pollutants in this region. Such knowledge is mainly obtained in previous studies using multi-year historical observations at limited measurement sites. There are concerns about spatial representativeness of these measurement locations, and confounding effects from changes in anthropogenic emissions over the analysis period. While modeling studies can control and minimize these limitations, the short simulation period usually makes temporally representative patterns difficult to discern. Our study simulates ozone formation in central California for the entire summer of 2000, with wide meteorological and air quality variations seen in both space and time, and thus provides a good opportunity to examine meteorological regimes that lead to different ozone production, transport, and accumulation in the Central valley. Using cluster analysis and principal component analysis, we determined distinctive meteorological regimes that are associated with different ozone spatial patterns in the Central Valley. In general, average ozone levels in the valley increase with temperature, while their spatial distribution depend on flow regimes, in particular, the strength of sea breezes and upslope flows. The regional meteorological effects are shown to explain the different ozone patterns in the valley, their dynamic relationship with each other, and their relationship to those in the upwind air basins. Our results can serve as a basis to study variability in ozone responses to emission controls and inter-basin pollutant transport under and across different temperature and flow regimes.

Jin, L.; Brown, N. J.; Harley, R. A.

2008-12-01

137

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

138

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

139

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

USGS Publications Warehouse

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

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

2012-01-01

140

ALSM and GIS Analysis of Debris Flow Fan Variability, Death Valley, CA  

NASA Astrophysics Data System (ADS)

Analysis of form in geomorphology has gone through numerous transitions that began with the qualitative assessments of form through field observations as well as an attempt to unravel the historical development of landscapes. The dissatisfaction with the historical approach led to an emphasis on quantitative measures and analyses of planimetric (2D) boundary conditions of surficial features. The advent of Airborne Laser Swath Mapping (ALSM) and other remotely sensed techniques provided access to high-resolution data and permitted geomorphologic research to move beyond 2D measures to more closely approximate the form in 2.5D space. The current study presents preliminary results from a GIS analysis of ALSM data of alluvial fan form in Death Valley, CA. Functional surficial units, identified from field observations and DEM data, from debris flow fans were extracted from the ALSM point cloud. The functional units consisted of channels, levees, snouts, and interfluves between levees of two separate debris flow channels. The morphometric characteristics of these features were compared using spatial statistical analyses. The spatial interpretation provides a 2.5D assessment of within- and between-fan variability. It explains similarities and differences between the geomorphometric signatures of debris flow fans in a hyper-arid setting. The findings have implications for process-response models and planning/management of these often inhabited features.

Wasklewicz, T.; Volker, H.

2003-12-01

141

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

142

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

143

Mars remote-sensing analog studies in the Badwater Basin, Death Valley, California  

NASA Astrophysics Data System (ADS)

The search for evaporites on Mars has important implications for the role that liquid water has played in shaping the planet's geologic, climatic, and potential biologic history. Orbital investigations of surface mineralogy are crucial to this exploration effort. With the exception of coarse-grained gray hematite at a restricted number of sites and trace amounts of carbonate in globally distributed dust deposits, the Thermal Emission Spectrometer (TES) and Thermal Emission Imaging System (THEMIS) instruments have yet to find widespread mineralogical evidence of aqueously formed minerals. This may reflect the coarse spatial resolution of TES (3 × 5 km/pixel) and low spectral resolution of THEMIS (10 bands between 6.5 and 14.5 ?m). Spectral mapping in the Badwater Basin, Death Valley, California, was conducted to better understand the capabilities of TES and THEMIS in detecting evaporite minerals. High-resolution MODIS/ASTER Airborne Simulator (MASTER) data, degraded to TES and THEMIS spatial resolutions, were used to evaluate the detection limits of sulfates and carbonates. To assess the validity of this spectral remote sensing, a quantitative ground truth analysis of surface mineralogy in the Badwater Basin was performed. The analysis was based on thin section petrography, X-ray diffraction, electron microprobe, and laboratory and field thermal emission spectrometer analyses. Taken together, the results of all five methods provided enough constraints for a robust interpretation that was in general agreement with the spectral remote-sensing mapping study for ~90% of the surface samples examined.

Baldridge, Alice M.; Farmer, Jack D.; Moersch, Jeffrey E.

2004-12-01

144

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

Microsoft Academic Search

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

Rolly E. Rimando; Peter L. K. Knuepfer

2006-01-01

145

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

NASA Astrophysics Data System (ADS)

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

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

1989-06-01

146

Descriptions and chemical analyses for selected wells in the Central Sacramento Valley, California  

USGS Publications Warehouse

The Sacramento Valley occupies the northern one-third of the Great Central Valley of California. The study area of this report includes about 1,200 square miles (3,100 square kilometers) adjacent to the Sacramento River from Knights Landing to Los Molinos, in parts of Yolo, Sutter, Colusa, Glenn, Butte, and Tehama Counties. Between April and August 1975, 559 wells were canvassed, and during September and October 1975, water samples were collected for chemical analysis from 209 of these wells. Field determinations of alkalinity, conductance, pH , and temperature were made on the site at the time of sampling. Samples were prepared in the field for shipment and analysis for individual constituents at the Geological Survey Central Laboratory, Salt Lake City, Utah. Descriptive data for water wells are listed, chemical data are tabulated, and the location of wells is shown on maps. (Woodard-USGS)

Fogelman, Ronald P.

1976-01-01

147

Invertebrate mercury bioaccumulation in permanent, seasonal, and flooded rice wetlands within California's Central Valley  

Microsoft Academic Search

We examined methylmercury (MeHg) bioavailability in four of the most predominant wetland habitats in California's Central Valley agricultural region during the spring and summer: white rice, wild rice, permanent wetlands, and shallowly-flooded fallow fields. We sampled MeHg and total mercury (THg) concentrations in two aquatic macroinvertebrate taxa at the inlets, centers, and outlets of four replicated wetland habitats (8 wetlands

Joshua T. Ackerman; A. Keith Miles; Collin A. Eagles-Smith

2010-01-01

148

Lateglacial and early Holocene climate oscillations in the Matanuska Valley, south-central Alaska  

Microsoft Academic Search

Here we present multi-proxy data from two cores taken from Hundred Mile Lake in the Matanuska Valley of south-central Alaska to investigate the climate, vegetation and deglaciation history of the last 14,000 years. The chronology of the cores was controlled by five AMS dates. Sediment lithology changes from clay at ?14–13ka (1ka=1000calBP), through marl at 13–8ka, to gyttja at 8–0ka.

Zicheng Yu; Karina N. Walker; Edward B. Evenson; Irka Hajdas

2008-01-01

149

Modeling Land Application of Food-Processing Wastewater in the Central Valley, California  

Microsoft Academic Search

California's Central Valley contains over 640 food-processing plants, serving a multi-billion dollar agricultural industry. These processors consume approximately 7.9 x 107 m3 of water per year. Approximately 80% of these processors discharge the resulting wastewater, which is typically high in organic matter, nitrogen, and salts, to land, and many of these use land application as a treatment method. Initial investigations

Y. Rubin; P. Benito; G. Miller; J. McLaughlin; Z. Hou; S. Hermanowicz; U. Mayer

2007-01-01

150

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

USGS Publications Warehouse

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

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

1978-01-01

151

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

Microsoft Academic Search

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

THOMAS H. POGSON; SUSAN M. LINDSTEDT

152

Impacts of Uranium Mining on Environment of Fergana Valley in Central Asia  

Microsoft Academic Search

\\u000a After collapse of the USSR and curbing of uranium extraction numerous pits, mines, waste dumps and tailings remained in the\\u000a territory of Fergana valley in Central Asia. These objects pose a serious threat to the environment and population of the\\u000a region. This paper considers the most problematic areas (hotspots) where various components of the environment are systematically\\u000a polluted with radionuclides

Isakbek Torgoev; Yuriy Aleshin; Gennadiy Ashirov

153

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

Microsoft Academic Search

The Hell's Gate alluvial fan of northern Death Valley has an area of 49.5km2, a radius of 11.8km, and a smooth 5–3° sloping surface interrupted by shallow (<0.5m), radially aligned gullies 1–4m wide. Facies analysis of 1–14m high exposures at 45 sites reveals that the fan is built almost entirely by water-flow processes. Two facies deposited by sheetflooding dominate the

T. C. Blair

2000-01-01

154

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

Microsoft Academic Search

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

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

1987-01-01

155

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

Microsoft Academic Search

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

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

156

Visualizing and Analyzing Geologic and Hydrologic Models of the Death Valley Regional Ground-water Flow System, Nevada and California  

Microsoft Academic Search

Numerical modeling of the Death Valley regional ground-water flow system, Nevada and California, involves the conceptualization and simulation of a complex and heterogeneous geologic and hydrologic system. The hydrogeologic characteristics of the region result from an arid climate and complex geology. Interbasin regional ground-water flow occurs through a thick Paleozoic carbonate-rock sequence, a locally thick Tertiary volcanic-rock sequence, and basin-fill

C. C. Faunt

2003-01-01

157

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

SciTech Connect

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

Inyo County

2006-07-26

158

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

159

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

USGS Publications Warehouse

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

Bartolino, James R.; Adkins, Candice B.

2012-01-01

160

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

161

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

162

Depositional processes and facies of Trail Fan sandflat: Death Valley, California  

SciTech Connect

A study was conducted of the alluvial fan to playa transition along Trail fan in Death Valley, California with the primary objectives of documenting sedimentary facies and textural features of so-called arid region sandflat. The study involved description of sedimentary structures along trenches and meter-deep cores, description of surficial bedforms, and collection of samples for lithological analyses. Surficial features of Trail Fan sandflat gradually change downdip as a function of texture, ground water depth, and runoff. They include: (1) tongues of mudflows; (2) shallow braided channels that taper out into mudflat or coalesced into single channels; (3) puffy grounds; and (4) flat-smooth surface of the mudflat. The sediment's texture shows a fining downdip trend except when the surface are draped by mudflows. Four facies are distinguished downdip from the alluvial fan to playa mudflat. Facies 1 consists of massive, light gray, matrix to grain supported gravel, and is interpreted as debris flow or streamflow deposit. Facies 2 consists of thin-bedded (0.6--0.06 m), tan, massive, gravelly mud and is interpreted as mudflow deposit. Facies 2 consists of repeated sequences of thick-bedded (0.15 to 0.3 m), massive to planar stratified, graveliferous sand with mud drape and is interpreted as poorly sorted sheetflood or streamflow deposit. Facies 4 consist of light gray, planar laminated, coarsening upward mud to muddy sand, and is interpreted as mudflat facies. This study shows that arid region sandflat facies is a mosaic of mudflow, debris flow, sheetflood and streamflow deposits and is more complex than previous sandflat models described.

Malicse, A.E.; Mazzullo, J.M.; Eide, M.G. (Texas A and M Univ., College Station, TX (United States))

1992-01-01

163

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

164

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

NASA Astrophysics Data System (ADS)

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

Del Pardo, Cecilia

165

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

NASA Astrophysics Data System (ADS)

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

Aslett, Zan

166

Airborne Laser Swath Mapping as a Tool to Study Active Deformation Along the Death Valley Fault Zone, California  

NASA Astrophysics Data System (ADS)

The degree to which fault loading and strain release rates are constant in time and space is one of the most fundamental, unresolved issues in modern tectonics. In order to understand how strain is distributed across plate boundaries we must compare slip rate data over a wide range of time scales. The Death Valley fault zone (DVFZ) is one of the last major missing pieces of the kinematic puzzle in the eastern California shear zone (ECSZ). Published models of geodetic data suggest the DVFZ is storing much, and perhaps almost all, of the Pacific-North American plate boundary strain in the ECSZ north of the Garlock fault. However, the scarcity of geochronologically constrained long-term slip rates makes it difficult to determine whether strain storage and release have been constant along this part of the plate boundary. We are using airborne laser swath mapping (ALSM) data, together with cosmogenic nuclide geochronology and field mapping to determine geologic slip rates over a variety of time scales on this section of the plate boundary. The scarcity of vegetation in the study area is ideal for acquisition of ALSM data to survey deformed geomorphic features; removal of data points related to returns from the top of plants does not reduce the point density of bare-earth shots, as it might in a heavily-canopied area. We have acquired 46 km2 of ALSM data from two locations along the northern DVFZ. In addition, approximately 100 km2 of ALSM data have been collected along the central Death Valley normal fault. The ALSM data highlight many dextral and normal fault offsets in alluvial fans along the western piedmonts of the Black and Grapevine Mountains. These data are particularly useful for active tectonic studies because the landscape can be artificially illuminated from any azimuth and sun angle to reveal subtle topographic features that may not otherwise be seen. The amount of mid-Pleistocene to Holocene displacement on the fault system can be determined by restoring alluvial channel offsets observed in the ALSM data along the DVFZ to their pre-faulting positions. Minimum fault offsets in surfaces of varying age range from < 5 m in the youngest offset surface to 390 m in the oldest deformed surface. We have also used the ALSM data to construct surficial geologic maps of offset fans on the basis of slope maps and surface roughness characteristics. Field mapping using the ALSM data as a base map will augment digital analyses of the topography. Cosmogenic nuclide geochronology (10Be) will constrain the ages of deformed surfaces, and generate precise intermediate- and long-term slip rates from the restored fault offsets. Comparison of these longer-term rate data with short-term geodetic data will allow us to determine whether strain storage and release have been constant over the Holocene-late Pleistocene time scales of interest. Of particular importance is whether the potential strain transient observed in the Mojave section of the ECSZ extends north of the Garlock fault and away from the zone of structural complexity associated with the Big Bend of the San Andreas fault.

Frankel, K. L.; Dolan, J. F.; Finkel, R. C.; Wasklewicz, T.

2005-12-01

167

Sudden death in the working population; a collaborative study in Central Japan  

Microsoft Academic Search

Aim Few epidemiological data are available describing the sudden death of persons in their prime. This study aims to elucidate when and how sudden death occurs among employees. Methods A total of 196 775 employees from 10 workplaces in Central Japan were surveyed for non-traumatic sudden death during 1989-1995. Demographic data and informa- tion regarding onset were collected by their

T. Kawamura; H. Kondo; M. Hirai; K. Wakai; A. Tamakoshi; T. Terazawa; S. Osugi; M. Ohno; N. Okamoto; T. Tsuchida; Y. Ohno; J. Toyama

1999-01-01

168

Drought Analyses of the California Central Valley Surface-Groundwater-Conveyance System  

NASA Astrophysics Data System (ADS)

Historically, California has experienced periods of long drought conditions. Isotopic analyses have indicated that naturally occurring droughts were most pronounced during the 15th century, when S.F. Delta inflows were less than 50 percent of the long term mean flows. During the last 150 years there has been an above average mean flow concurrent with the onset of agricultural development. More importantly, is the advancement of the California water conveyance system and irrigation farming that came into existence during the latter half of the 20th century. This was during a period of historically wet conditions, and until recently, water resource managers have relied on stationary conditions as part of their management strategy. To provide water resources decision makers with the tools needed for better understanding the consequences of persistent droughts, we have begun a series of numerical investigations to determine system behavior and economic impacts under a range of conditions. Our investigations of California Central Valley impacts of sustained droughts are based on a series of specified reductions (10 to 70 percent) in net surface flows for periods ranging from 10 to 60 years and applied to the California Department of Water Resources' California Central Valley Simulation Model (C2VSIM). This simplified methodology represents a means to evaluate the impacts of reductions in net surface flow from reservoirs. The goals of this study are to understand how reductions in surface water are handled within C2VSIM, how groundwater pumping compensates the reduced inflow, to what degree the water table is reduced, and how this system recovers. Pumping costs will also be calculated for each case. Finally, an economic analysis of the impacts on agriculture as related to changes in farming practices that may be needed to maintain a sustainable agricultural economy in the Central Valley under the range of imposed drought conditions is presented.

Miller, N. L.; Dale, L. L.; Vicuna, S. D.

2006-12-01

169

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

170

Aeromagnetic maps with geologic interpretations for the Tularosa Valley, south-central New Mexico  

USGS Publications Warehouse

An aeromagnetic survey of the Tularosa Valley in south-central New Mexico has provided information on the igneous rocks that are buried beneath alluvium and colluvium. The data, compiled as residual magnetic anomalies, are shown on twelve maps at a scale of 1:62,500. Measurements of magnetic properties of samples collected in the valley and adjacent highlands give a basis for identifying the anomaly-producing rocks. Precambrian rocks of the crystalline basement have weakly induced magnetizations and produce anomalies having low magnetic intensities and low magnetic gradients. Late Cretaceous and Cenozoic intrusive rocks have moderately to strongly induced magnetizations. Precambrian rocks produce prominent magnetic anomalies having higher amplitudes and higher gradients. The Quaternary basalt has a strong remanent magnetization of normal polarity and produces narrow anomalies having high-magnetic gradients. Interpretations include an increase in elevation to the top of buried Precambrian rock in the northern part of the valley, a large Late Cretaceous and Cenozoic intrusive near Alamogordo, and a southern extension of the intrusive rock exposed in the Jarilla Mountains. Evidence for the southern extension comes from a quantitative analysis of the magnetic anomalies..

Bath, G. D.

1977-01-01

171

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

SciTech Connect

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

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

1987-09-01

172

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

173

Quaternary tectonics in the central Interandean Valley, Ecuador: Fault-propagation folds, transfer faults and the Cotopaxi Volcano  

Microsoft Academic Search

We studied the Quaternary tectonics of the central Interandean Valley (IV, Ecuador), around the active Cotopaxi volcano, by field geological–structural survey, analysis of seismicity, precise levelling of river terraces and numerical modelling. North of the volcano, there are main Quaternary west-dipping reverse faults located along the western side of the valley. At the Cotopaxi foothills, we found NNE-SSW-striking, vertical, right-lateral

Emilia Fiorini; Alessandro Tibaldi

174

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

175

New observations of VOC emissions and concentrations in, above, and around the Central Valley of California  

NASA Astrophysics Data System (ADS)

Large portions of the Central Valley of California are out of compliance with current state and federal air quality standards for ozone and particulate matter, and the relative importance of biogenic and anthropogenic VOC emissions to their photochemical production in this region remains uncertain. In 2009-2011 multiple measurement campaigns were completed investigating the VOC emission inventory and concentration distributions. In 2009 BVOC emissions from more than 20 species of major agricultural crops in California were measured in a greenhouse using branch enclosures by both PTRMS and in-situ GC. Overall, crops were found to emit low amounts of BVOC compared to the natural forests surrounding the valley. Crops mainly emitted methanol and terpenes, with a broad array of other species emitted at lower levels, and all the measured crops showed negligible emissions of isoprene. Navel oranges were the largest crop BVOC emitters measured so a full year of flux measurements were made in an orange grove near Visalia in 2010 by eddy covariance(EC)-PTRMS with two multi-week periods of concentration measurements by hourly in-situ GC, and one month of high mass resolution flux measurements by EC-PTR-TOF-MS. The dominant BVOC emissions from the orange grove were methanol and terpenes, followed by acetone, acetaldehyde, and a low level of emissions for many other species. In 2011 aircraft eddy covariance measurements of BVOC fluxes were made by EC-PTRMS covering a large area of California as part of the California Airborne Bvoc Emission Research in Natural Ecosystem Transects (CABERNET) campaign aimed at improving BVOC emission models on regional scales, mainly profiling BVOC emissions from oak woodlands surrounding the Central Valley. In 2010, hourly in-situ VOC measurements were made via in-situ GC in Bakersfield, CA as part of the CalNex experiment. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel. Measurements by in-situ GC included more than 200 anthropogenic and biogenic VOCs with a wide range of volatilities (up to 17 carbon atoms in size) and various functional groups (e.g. aldehydes, ketones, alcohols, halogens, sulfur, & nitrogen). Finally, in 2011 vertical profiles of VOC were made at 5 heights on a communication tower at Walnut Grove (~20 miles south of Sacramento) from 30' to 1550' by PTRMS. Results from all of these studies combined provide a novel overview of the distribution of VOC emissions and concentrations in, around, and above the Central Valley of California.

Goldstein, A. H.; Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Ormeno, E.; Holzinger, R.; Misztal, P. K.; Karl, T. R.; Guenther, A. B.; Fischer, M. L.; Harley, R. A.; Karlik, J. F.

2011-12-01

176

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

177

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

SciTech Connect

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

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

1990-03-01

178

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

179

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

180

Conodont biostratigraphy of the Ordovician-Silurian boundary in the Central Appalachian Valley and Ridge Province  

SciTech Connect

Conodont biostratigraphy of the Ordovician-Silurian boundary in the Central Appalachian Valley and Ridge Province is based primarily on lithologic criteria. Although the boundary is precisely defined lithologically, virtually nothing is known about the biostratigraphic relationships in this interval due to a historic lack of detailed studies in this region. The present study is based on nearly 50 samples from 7 sections in Tennessee and Virginia, aimed at establishing a conodont-based biostratigraphic framework useful for local and regional correlation of lithostratigraphic units and boundaries. The data at hand show uppermost Ordovician rocks in this region have conodont faunas which are characterized by species of Oulodus, Aphelognathus, Phragmodus, and Plectodina. These faunas represent associations which locally correspond to the Oulodus velicuspis to Aphelognathus divergens Zones. Lowermost Silurian rocks contain faunas dominated by species of Ozarkodina, Distomodus, Pranognathus, and Walliserodus that correspond to the faunas of the Distomodus kentuckyensis Zone. Conodont ages indicate that the uppermost Ordovician rocks in the Central Appalachians range in age from upper Edenian to upper Richmondian and lowermost Silurian rocks range in age from upper Rhuddanian to lower Telychian in age. No conodont faunas which characterize the uppermost Richmondian, Gamachian, or lowermost Rhuddanian have yet been identified. The results of this study are in agreement with those of out previous study of the Southern Appalachian Valley and Ridge Province.

Philips, P.L. Jr.; Hall, J.C. (Univ. of North Carolina, Wilmington, NC (United States). Dept. of Earth Sciences)

1993-03-01

181

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

182

Viscous flow lobes in central Taylor Valley, Antarctica: Origin as remnant buried glacial ice  

NASA Astrophysics Data System (ADS)

Viscous flow lobes are common throughout the McMurdo Dry Valleys (MDV) of Antarctica. These features have been described as rock glaciers, gelifluction lobes, solifluction lobes, talus mobilized by pore ice and/or segregation ice, and debris-covered glaciers. We investigate the origin, modification, and flow of a 2-km-long lobe (East Stocking Lobe or ESL) along the north wall of central Taylor Valley using field mapping techniques, shallow seismic surveys, time-dependent displacement surveys, and isotopic analyses of buried-ice samples. On the basis of these integrated analyses, we show that the ESL is cored with remnant glacier ice, most probably derived from an advance of nearby Stocking Glacier ˜ 130 kyr BP. Seismic data, coupled with results from ice-flow modeling assuming plastic flow of clean ice, suggest that the buried core of glacier ice is ˜ 14- to 30-m thick. Near its terminus, the ESL flows at a rate of ˜ 2.4 to 6.7 mm a - 1 . The loose drift that caps the buried ice (typically < 1 m thick) is composed of moderately stratified sand- and gravel-sized clasts; it is dry (1-3% soil gravimetric water content; GWC), except near ephemeral stream channels and the margins of melting snow banks (6-25% GWC). Stable isotopic analyses of samples from the upper 30 cm of the ice lie on a slope of ˜ 5.8 (when plotted on a ?D vs. ?18O graph), well below the local meteoric water line of 7.75, suggesting modification by freeze/thaw processes and evaporation/sublimation. Measured air and soil temperatures show that intermittent melting is most likely possible during summer months where buried ice is ? 35 cm below the ground surface. Morphological comparisons with ice-cored deposits in upland regions of the Dry Valleys, e.g., Mullins and Beacon Valleys (30 km inland and ˜ 500 m higher in elevation), and near the coast (40 km distant and ˜ 500 m lower) reveal marked contrasts in the style of near-surface ice degradation and cryoturbation. From these morphological comparisons, we infer that buried-ice deposits in the stable upland zone have not experienced the relatively warm climate conditions now found at the ESL and at lower elevations in the Dry Valleys region (e.g. sustained summertime temperatures of ?-4 °C) for the last several million years.

Swanger, Kate M.; Marchant, David R.; Kowalewski, Douglas E.; Head, James W., III

2010-08-01

183

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

184

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

NASA Astrophysics Data System (ADS)

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

Beyene, Mengesha Assefa

185

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

186

Estimated natural ground-water recharge, discharge, and budget for the Dixie Valley area, west-central Nevada  

USGS Publications Warehouse

The Dixie Valley area includes seven valleys in west-central Nevada (Dixie, Fairview, Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys; total, 2,380 square miles). Dixie Valley receives surface-water and ground-water flow from Stingaree, Cowkick, Eastgate, Pleasant, and Jersey Valleys and subsurface flow from Fairview Valley, which is a topographically closed basin. The relation between precipitation and altitude was re-evaluated for the Dixie Valley area using new data, and empirical estimates of recharge were revised accordingly. The revised estimate of total recharge is 23,000 acre-feet per Re-evaluation of ground-water discharge focused on Dixie Valley as the largest basin in the study area. Phreatophytic vegetation was mapped and partitioned into nine zones on the basis of species composition and foliage density. For woody phreatophytes, annual evapotranspiration rates of 0.7 cubic feet of water per cubic foot of foliage for greasewood and 1.1 cubic feet of water per cubic foot of foliage for rabbitbrush were adapted from lysimeter studies near Winnemucca, Nevada. These rates were multiplied by the foliage density of the respective phreatophytes in each zone to estimate a specific rate for that zone. Rates for salt-grass (0.5 to 0.8 foot per year) and the playa surface (0.1 to 0.3 foot per year) were based on a range of rates. used in other recent studies in western and central Nevada. These rates were multiplied by the areas of the zones to produce estimates of the annual volume of ground water discharged. The discharge estimated for Dixie Valley is between 17,000 and 28,000 acre-feet per year. The revised discharge estimate for the entire Dixie Valley area is between 20,000 and 31,000 acre-feet per year. The revised ground-water budget for the entire Dixie Valley study area has a total recharge of about 23,000 acre-feet per year. This is within the range of estimates of natural discharge--from 20,000 to 31,000 acre-feet per year. For Dixie Valley alone, the total recharge of about 8,900 acre-feet per year and the estimated subsurface inflow from tributary areas of about 11,000 acre-feet per year produce an estimated total inflow of about 20,000 acre-feet per year. This compares with the discharge estimate of 17,000 to 28,000 acre-feet per year.

Harrill, J. R.; Hines, L. B.

1995-01-01

187

Three-dimensional P-wave Velocity Structure of the Bear Valley Region of Central California  

NASA Astrophysics Data System (ADS)

The three-dimensional P-wave velocity structure of the Bear Valley region of central California is determined by applying a circular ray-tracing technique to 1735 P-wave arrivals from 108 locally recorded earthquakes. Comparison of the results obtained from one-dimensional and laterally varying starting models shows that many of the features in the structure determined are fairly insensitive to the choice of the starting model. Velocities associated with the Gabilan granites southwest of the San Andreas Fault are slightly higher than those in the Franciscan formation to the northeast, and these two features are separated in the southern part of the region by a narrow fault zone with very low velocities. In the southeastern part of the region, where the Gabilan granites do not abut the San Andreas Fault, the low velocities of the fault zone cross over to the southwestern side of the fault. They also appear to extend to depths of at least 15km, thus locally reversing the contrast across the San Andreas Fault that prevails farther to the northwest. In the northwestern part of the region, the low velocities of the fault zone split and follow the surface traces of the San Andreas and Calaveras Faults, but do not appear to extend to depths much deeper than about 6km. There also appears to be a well-defined contrast in structure in the middle of the Santa Clara Valley, suggesting the existence of a fault in the basement of the valley that may be a southern extension of the Sargent Fault into this region. Relocated hypocenters beneath the San Andreas Fault cluster in a zone that dips about 80° southwest and intersects the surface trace of the fault in the southern part of region.

Lin, C.-H.; Roecker, S. W.

188

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

189

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

190

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

NASA Astrophysics Data System (ADS)

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-dipping fault imaged by COCORP studies. Similarly, younger deformation in upper Wingate Wash is

Luckow, Heather Golding; Pavlis, Terry L.; Serpa, Laura F.; Guest, Bernard; Wagner, David L.; Snee, Lawrence; Hensley, Tabitha M.; Korjenkov, Andrey

2005-12-01

191

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

192

Chemical quality of ground water in the central Sacramento Valley, California  

USGS Publications Warehouse

The study area includes about 1,200 square miles in the central Sacramento Valley adjacent to the Sacramento River from Knights Landing to Los Molinos, Calif. With recent agricultural development in the area, additional land has been brought under irrigation from land which had been used primarily for dry farming and grazing. This report documents the chemical character of the ground water prior to water-level declines resulting from extensive pumping for irrigation or to changes caused by extensive use of imported surface water. Chemical analyses of samples from 209 wells show that most of the area is underlain by ground water of a quality suitable for most agricultural and domestic purposes. Most of the water sampled in the area has dissolved-solids concentrations ranging from 100 to 700 milligrams per liter. The general water types for the area are a calcium magnesium bicarbonate or magnesium calcium bicarbonate and there are negligible amounts of toxic trace elements. (Woodard-USGS)

Fogelman, Ronald P.

1978-01-01

193

The Dynamics of Social Indicator Research for California's Central Valley in Transition  

PubMed Central

How can social indicator research improve understanding of community health as well as inform stakeholders about the assets disadvantaged communities have for coping with disparities? This paper describes the development and evolution of the Partnership for Assessment of Communities (PAC) and its best practices for social indicator research. The PAC will be of interest to researchers across multiple disciplines for a number of reasons. First, PAC is a working model of best practices for multidisciplinary scholarly inquiry. Second, it has developed an integrated model of quantitative and qualitative methodology to define and measure community health as compared to traditional quality-of-life indicators. Third, it serves as an example of “action research,” in that the findings have the potential to make an impact on community stakeholders and policy outcomes in the greater Central San Joaquin Valley of California, a region characterized by deep social and economic disparities.

Hernandez, Marcia D.; Sylvester, Dari E.; Weffer, Simon E.

2010-01-01

194

Serological study of amebiasis and toxoplasmosis in the Lindu Valley, Central Sulawesi, Indonesia.  

PubMed

Results of a serology survey in April 1972 for Entamoeba histolytica and Toxoplasma gondii antibodies among 484 inhabitants of the isolated Lake Lindu Valley of Central Sulawesi (Celebes) are presented. Indirect hemagglutination antibody titers for amebiasis were found in over 10% of the population, although only 3.7% demonstrated significant titers of 1:128 or greater. There appeared to be no relationship between antibody titers and the age and sex of individuals tested, and the frequency distribution of antibody titers indicates a low prevalence of invasive amebiasis in the population. Indirect hemagglutination antibody titers for Toxoplasma gondii equal to or greater than 1:32 were found in 27.1% of the total population, and it appeared that the prevalence of titers increased with age in both sexes. More families with cats had Toxoplasma gondii antibody titers than families without cats. PMID:171809

Clarke, M D; Cross, J H; Carney, W P; Hadidjaja, P; Joesoef, A; Putrali, J; Sri Oemijati

1975-09-01

195

Planned updates and refinements to the central valley hydrologic model, with an emphasis on improving the simulation of land subsidence in the San Joaquin Valley  

USGS Publications Warehouse

California's Central Valley has been one of the most productive agricultural regions in the world for more than 50 years. To better understand the groundwater availability in the valley, the U.S. Geological Survey (USGS) developed the Central Valley hydrologic model (CVHM). Because of recent water-level declines and renewed subsidence, the CVHM is being updated to better simulate the geohydrologic system. The CVHM updates and refinements can be grouped into two general categories: (1) model code changes and (2) data updates. The CVHM updates and refinements will require that the model be recalibrated. The updated CVHM will provide a detailed transient analysis of changes in groundwater availability and flow paths in relation to climatic variability, urbanization, stream flow, and changes in irrigated agricultural practices and crops. The updated CVHM is particularly focused on more accurately simulating the locations and magnitudes of land subsidence. The intent of the updated CVHM is to help scientists better understand the availability and sustainability of water resources and the interaction of groundwater levels with land subsidence. ?? 2011 ASCE.

Faunt, C. C.; Hanson, R. T.; Martin, P.; Schmid, W.

2011-01-01

196

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

Microsoft Academic Search

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

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

2000-01-01

197

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

Microsoft Academic Search

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

Qi Zhang; Cort Anastasio

2001-01-01

198

Very Fine and Ultrafine Metals and Ischemic Heart Disease in the California Central Valley 1: 2003–2007  

Microsoft Academic Search

The enhancement of mortality associated with cardiovascular and specifically ischemic heart disease (IHD) has been observed in the southern California Central Valley since at least 1990, and it continues to be a major source of mortality. While there is a strong statistical association of IHD with wintertime PM2.5 mass, the causal agents are uncertain. Medical studies identify some potential causal

Thomas A. Cahill; David E. Barnes; Nicholas J. Spada; Jonathan A. Lawton; Thomas M. Cahill

2011-01-01

199

U\\/Th dating of freshwater travertine from Middle Velino Valley (Central Italy): paleoclimatic and geological implications  

Microsoft Academic Search

Six travertine bodies outcropping along the Middle Velino Valley (Central Italy) have been studied and dated using the U\\/Th method in order to obtain new chronological constraints for the recent geological evolution of the area. The lithological and sedimentological characteristics of travertines have been described, showing that such deposits can be referred to waterfall, pool terraces and gentle slopes environment.

M Soligo; P Tuccimei; R Barberi; M. C Delitala; E Miccadei; A Taddeucci

2002-01-01

200

EPIDEMIOLOGY OF PIERCE'S DISEASE IN THE CENTRAL SAN JOAQUIN VALLEY OF CALIFORNIA: FACTORS AFFECTING PATHOGEN DISTRIBUTION AND MOVEMENT Project Leaders  

Microsoft Academic Search

The overall goal of this project is enhance our present understanding of the epidemiology of Pierce's disease (PD) in the central San Joaquin Valley (SJV) of California by elucidating factors that influence its geographical distribution and movement. The objective of this research will be to characterize the seasonal abundance and dispersal biology of the glassy- winged sharpshooter (GWSS), a primary

Russell Groves; Jianchi Chen; Kent Daane; Marshall Johnson; Daniel Bigham

201

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

Microsoft Academic Search

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

Martha C. Volkoff; Robert G. Titus

2007-01-01

202

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

Microsoft Academic Search

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

Tony Stevensonf; Basil Davisf

203

Numerical Simulation of Ground-Water Flow in the Central Part of the Western San Joaquin Valley, California.  

National Technical Information Service (NTIS)

This report documents the development of a three-dimensional, finite-difference numerical model of the ground-water flow system in the central part of the western San Joaquin Valley. The model described in this report can be used to evaluate the response ...

K. Belitz S. P. Phillips J. M. Gronberg

1993-01-01

204

Distribution of Glyphosate-Resistant Horseweed (Conyza Canadensis) and Relationship to Cropping Systems in the Central Valley of California  

Technology Transfer Automated Retrieval System (TEKTRAN)

Horseweed is an increasing problem in perennial crops and non-crop areas of the Central Valley of California. Similar to the situation in glyphosate-tolerant crops in other regions, glyphosate-based weed management strategies in perennial crops and non-crop areas have resulted in selection of a gly...

205

Diagenetic controls on primary and secondary porosity in valley-fill marine sandstones - Misener Formation, north-central Oklahoma  

Microsoft Academic Search

The Devonian Misener formation in north-central Oklahoma consists of a series of discontinuous sandstone and shale bodies deposited in erosional topographic lows on the post-Hunton unconformity surface of north-central Oklahoma. Paleontological, mineralogical, and sedimentological evidence supports a marine valley-fill depositional setting including both channel and nonchannel facies. Abrupt changes in sandstone thickness and reservoir properties are characteristic of Misener sandstones.

D. Prezbindowski; R. D. Fritz; B. M. Francis

1989-01-01

206

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

NASA Astrophysics Data System (ADS)

Hidden Valley is located in the north-central McCullough Range south of Las Vegas along the western edge of the Northern Colorado River extensional corridor (NCREC) in the central Basin and Range. The western portion of the NCREC is an area of highly extended crust, but the McCullough Range is a relatively unextended block. Hidden Valley is bound on all sides by volcanic rock of the central and northern McCullough Mountains. The evolution of Hidden Valley is still unresolved due to a lack inter-basin exposure. Four proposed models have been suggested for the formation of Hidden Valley. Models include a volcanic sag basin, half-graben, pull-apart basin, and antithetic synclinal accommodation zone. An east-west trending high-resolution seismic reflection/refraction profile and gravity measurements were collected in the valley to resolve the basin formation, determine the relationship between volcanism and extension in the area as well as to determine the basin structure. From the eastern edge of the basin moving west, a 2.18 km seismic profile was acquired in the summer of 2005 using a combination of alternating hammer source and 15-second linear vibroseis sweep. First arrivals were used to create a velocity model along this profile and integrated on the seismic reflection data. Gravity measurements were taken across the valley at 1 km spacing and at 250 m across the center of the valley during the winter of 2006. Gravity modeling was performed at the regional scale and local scale. Seismic reflection/refraction data were used for accurate gravity modeling and local well data was integrated into all data sets. Preliminary interpretations of the data sets show a thin basin fill on the eastern edge of the basin with basaltic basement rock on that side of the valley. The basin fill thickens to the middle of the valley, possibly associated with faulting. Results show little faulting and syn-tectonic volcanism, which would strengthen the evidence for volcanic sagging. Further refinement of the integrated data sets and modeling could reveal normal faulting, which alternatively would suggest a half-graben or accommodation zone. Faulting of Holocene sediments would indicate a possible seismic hazard for the growing population of the Las Vegas area.

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

2006-12-01

207

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

Microsoft Academic Search

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

C. C. Faunt; A. K. Turner

1998-01-01

208

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

Microsoft Academic Search

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

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

2007-01-01

209

Geologic Cross Sections of Parts of the Colorado, White River, and Death Valley Regional Ground-Water Flow Systems, Nevada, Utah, and Arizona.  

National Technical Information Service (NTIS)

This report contains 10 interpretive cross sections and an integrated text describing the geology of parts of the Colorado, White River, and Death Valley regional ground-water flow systems, Nevada, Utah, and Arizona. The primary purpose of the report is t...

W. R. Page D. S. Scheirer V. E. Langenheim

2006-01-01

210

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies. LANDSAT TM investigation proposal TM019  

Microsoft Academic Search

Processing and interpretation of Thematic Mapper (TM) data, extensive field work, and processing of SPOT data were continued. Results of these analyses led to the testing and rejecting of several of the geologic\\/tectonic hypotheses concerning the continuation of the Garlock Fault Zone (GFZ). It was determined that the Death Valley Fault Zone (DVFZ) is the major through-going feature, extending at

Michael Abrams; Ken Verosub

1987-01-01

211

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

212

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

SciTech Connect

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

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

2001-12-31

213

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

214

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

215

Recharge response to interannual and multidecadal climate variability and implications for groundwater resources of the Central Valley aquifer, California  

NASA Astrophysics Data System (ADS)

Climate variability on interannual to multidecadal temporal scales has substantial implications for management and sustainability of water resources, yet are poorly understood throughout much of the United States. Climate forcings on these timescales partially control precipitation distribution, temperature fluctuations, drought occurrence and severity, streamflow, and recharge. Reliable predictions of future climate and subsequent adaptation of groundwater management strategies in vulnerable aquifers, such as the Central Valley aquifer located in central California of the United States, requires improved understanding of climate variability on interannual to multidecadal timescales and the associated responses in recharge rates. Groundwater withdrawals from the Central Valley aquifer are the second largest of all aquifers in the United States and are used to support one of the largest agricultural economies. However, the effects of the El Niño Southern Oscillation (ENSO) (2 to 6 year cycle), Pacific Decadal Oscillation (PDO) (10 to 25 year cycle), and Atlantic Multidecadal Oscillation (AMO) (50 to 80 year cycle) on recharge rates and groundwater levels in the Central Valley aquifer previously have not been quantified. In this study, singular spectrum analysis (SSA) was used to identify the principal components of groundwater level time series from selected wells in Central Valley aquifer that contribute to the greatest amount of variance in the record. In each of the time series analyzed, the PDO was the most significant contributor to groundwater level fluctuations. Wavelet analysis was also used to examine the nonstationary phase relation of multiple time series to identify significance and duration of each forcing. A consistent phase relation of multiple signals suggests possible coherence between climate forcings and groundwater levels, and also indicates the effect of the PDO on groundwater levels. These findings support the conclusion that interannual to multidecadal climate variability, especially PDO, contributes to fluctuations in available groundwater in the Central Valley, and is therefore a necessary component of future water resource management. Findings from the Central Valley aquifer are presented within the context of the effects of climate variability on multiple aquifers across the United States, and support the use of spatiotemporal variations in recharge rates due to climate variability within adaptation strategies for groundwater sustainability.

Kuss, A. M.; Gurdak, J. J.

2010-12-01

216

Are the stair case terraces in the Inylchek Valley (Central Tien Shan, Kyrgyzstan) of neotectonic or sedimentary origin?  

NASA Astrophysics Data System (ADS)

In 2011 we performed fieldwork at the Global Change Observatory "Gottfried Merzbacher" east of Gribkov Base. High-resolution satellite images show at least six ridges which can be traced on the northern slopes of the Inylchek Valley. These ridges parallel each other and are intersected by smaller erosional valleys. Detailed mapping of outcrops in the tributary valleys revealed intensively folded Paleozoic formations overlain by glacial and fluvioglacial deposits of a thickness of tens of meters. From the sedimentological point of view we differentiate between kame terraces (KT), which are defined as depositional terraces perched on valley sides, deposited by meltwater streams flowing between lateral glacier margins and the adjacent valley wall, and fluvial terraces (FT), deposited above the niveau of the present Inylchek River. In the investigated sector of the Inylchek Valley we mapped FT1 and FT2 above the recent valley floor of the braided Inylchek River. These terraces intersect with the debris fans of the tributary streams. Up the northern hill we mapped at least four higher ridges, which are interpreted as remnants of kame terraces. The first and second of these higher ridges do not differ significantly in altitude and are therefore considered remnants of KT1a & b, followed up by two higher kame terraces KT2 and KT3. Each kame terrace represents one distinct stage of deglaciation of the valley glacier in the Southern Inylchek Valley. When another lower kame terrace was deposited, the higher terrace partly eroded along the valley wall and finally turned into a ridge. The observation that former fluvioglacial terraces today form ridges between incised valleys provides an example for an inverted relief. From the morphology of six ridges on the northern slope of the Inylchek Valley we derive the following succession of glacial and periglacial processes: 1) The highest kame terrace 3 (KT3) was deposited between the glacier margin of the former Inylchek Glacier at 4000 m altitude and the adjacent valley wall. 2) The next lower kame terrace (KT2) at about 3920 m altitude documents the deglaciation of the Southern Inylchek Glacier by 80 metres. 3) The lowest kame terrace (KT1) is preserved at an altitude of 3850 m a.s.l., indicating that the Southern Inylchek Glacier melted down another 70 metres. 4) After the retreat of the Glacier at least two fluvial terraces document proglacial sedimentation in a braided river system of the Inylchek Valley (upper fluvial terrace FT2 and lower terrace FT1). 5) In the studied Gribkov sector the recent Inylchek River eroded FT1 by three meters. Despite the fact that many recent, historical and paleo-earthquakes have been recorded in the Northern and Central Tien Shan, and that many scarps and even terraces may have resulted either from slides or from neotectonic tilting, we do not interpret the set of multiple ridges on the northern slope of Inylchek Valley as of tectonic origin but present arguments for their fluvioglacial evolution.

Häusler, H.; Kopecny, A.; Leber, D.

2012-04-01

217

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

218

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

219

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

220

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

221

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

222

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

Microsoft Academic Search

In the 1960s, a major hydrogeologic investigation was conducted at the Nevada Test Site (NTS, Figure 1) that included drilling, hydraulic testing, and hydrogeochemical studies in conjunction with geologic mapping and geophysical surveys. This work demonstrated that a large part of south central Nevada is underlain by thick (several kilometers) highly fractured Paleozoic carbonate rocks that typically act as an

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

2005-01-01

223

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

SciTech Connect

A series of drought simulations were performed for the California Central Valley using computer applications developed by the California Department of Water Resources and historical datasets representing a range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping patterns, and water demand were held fixed at the 2003 level and water supply was decreased by amounts ranging between 25 and 50%, representing light to severe drought types. Impacts were examined for four hydrologic subbasins, the Sacramento Basin, the San Joaquin Basin, the Tulare Basin, and the Eastside Drainage. Results suggest the greatest impacts are in the San Joaquin and Tulare Basins, regions that are heavily irrigated and are presently overdrafted in most years. Regional surface water diversions decrease by as much as 70%. Stream-to-aquifer flows and aquifer storage declines were proportional to drought severity. Most significant was the decline in ground water head for the severe drought cases, where results suggest that under these scenarios the water table is unlikely to recover within the 30-year model-simulated future. However, the overall response to such droughts is not as severe as anticipated and the Sacramento Basin may act as ground-water insurance to sustain California during extended dry periods.

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

2009-05-15

224

High Resolution Monitoring of Algal Growth Dynamics in a Hypereutrophic River in the Central Valley, California  

NASA Astrophysics Data System (ADS)

The lower San Joaquin River in California's Central Valley experiences periods of hypoxia during the late summer and fall that is detrimental to aquatic organisms and migration of fall-run chinook salmon and steelhead trout. Hypoxia is attributable, in part, to excess nutrients from urban waste water and agricultural runoff, which contribute to growth of high concentrations of phytoplankton. This study examined spatial and temporal growth patterns that control algal loading using continuous fluorescence measurements at three sites along a 50 km section of the lower San Joaquin River between April and October. A strong diel fluorescence signal was observed and associated grab samples verified that fluorescence was an accurate measure of chlorophyll. Peak chlorophyll concentrations occurred between 18:00 and 20:00 and minimum concentrations between 10:00 and 12:00. Maximum concentrations were nearly two times greater than minimum concentrations although this ratio varied temporally and spatially. Although the mechanism for the diel chlorophyll signal is not very well understood several parameters including temperature, irradiance, turbidity, residence time, stream depth, and zooplankton grazing were considered within the scope of this study. This study highlights the importance of considering high resolution sampling on algal loading rates within heavily impacted riverine systems.

Henson, S. S.; Dahlgren, R.; van Nieuwenhuyse, E.; O'Geen, A. T.; Gallo, E. L.; Ahearn, D. S.

2005-05-01

225

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

226

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

227

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

228

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

USGS Publications Warehouse

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

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

1983-01-01

229

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

2010-02-17

230

BVOC and tropospheric ozone fluxes from an orange orchard in the California Central Valley  

NASA Astrophysics Data System (ADS)

Citrus plants, especially oranges, are widely cultivated in the Central Valley of California and in many other 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 navel orange orchard in Exeter, California. The CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously using 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 40 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 5 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. 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. BVOC fluxes were highly temperature dependent, while ozone fluxes were more dependent on the physiology of the orchard, consistent with dominant removal occurring through the stomatal opening. The current research is aimed at: 1. Quantifying the uptake of O3 by citrus and partitioning it into stomatal and non-stomatal processes; 2. Quantifying the BVOC emissions and their dependence on physical and ecophysiological parameters.

Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Karlik, J. F.; Goldstein, A. H.

2010-12-01

231

Constraints on the post-middle-Pleistocene tectonic development of the Confidence Hills, southern Death Valley, California  

NASA Astrophysics Data System (ADS)

Our recent field mapping and tephrochronology offers new constraints on the style, timing, and rates of middle-Pleistocene-to-recent deformation in the Confidence Hills (CH), southern Death Valley. Movement on the active trace of the Southern Death Valley fault zone (SDVFZ) was preceded by earlier large-scale, northeast-vergent folding. This earlier folding involves several hundred meters of conformable late-Pliocene-to-middle-Pleistocene strata, which together form the common limb of a locally overturned fault-propagation fold pair. Geometric relations require that the blind thrust(s) responsible for earlier folding in the CH root well to the southwest of the active trace of the SDVFZ, which raises questions concerning previous flower structure models for earlier folding in the CH. Earlier folding began after deposition of Upper Glass Mountain tephra (1.1-0.9 Ma), which lies within the uppermost section of conformable, locally overturned Confidence Hills Formation(CHF), and ended prior to deposition of unconformably overlying fanglomerate, which contain tephra layers we tentatively correlate to the Bishop (0.76 Ma) and Lava Creek B (0.64 Ma) tephra. Earlier folding resulted in greater than 400 m structural relief and nearly 600 m of shortening in the span of 140-340 ka, yielding a middle-Pleistocene shortening rate of ~1.8-4.3 mm/yr. Dextral slip along the mappable traces of the SDVFZ began after earlier fault-propagation folding and also after deposition of the 0.76-0.64-Ma fanglomerates. Net right-lateral offset along the fault zone is well constrained ~4-km south of Shoreline Butte where a steeply-dipping contact marking the base of volcaniclastic conglomerate of the CHF is offset ~650 m. These relations yield a minimum post-middle-Pleistocene slip rate of ~1 mm/yr for the SDVFZ. Post-0.64-Ma shortening within the CH has been minor relative to earlier folding. The earlier fault-propagation folding in the CH appears to be related to a short-lived episode of northeast-directed motion of the Owlshead Mountains block, which was likely accommodated by left-lateral slip along the Wingate Wash fault.

Goodman, J. T.; Caskey, S. J.

2009-12-01

232

Congenital central hypoventilation syndrome and sudden infant death syndrome: disorders of autonomic regulation.  

PubMed

Long considered a rare and unique disorder of respiratory control, congenital central hypoventilation syndrome has recently been further distinguished as a disorder of autonomic regulation. Similarly, more recent evidence suggests that sudden infant death syndrome is also a disorder of autonomic regulation. Congenital central hypoventilation syndrome typically presents in the newborn period with alveolar hypoventilation, symptoms of autonomic dysregulation and, in a subset of cases, Hirschsprung disease or tumors of neural crest origin or both. Genetic investigation identified PHOX2B, a crucial gene during early autonomic development, as disease defining for congenital central hypoventilation syndrome. Although sudden infant death syndrome is most likely defined by complex multifactorial genetic and environmental interactions, it is also thought to result from central deficits in the control of breathing and autonomic regulation. The purpose of this article is to review the current understanding of these autonomic disorders and discuss the influence of this information on clinical practice and future research directions. PMID:23465774

Rand, Casey M; Patwari, Pallavi P; Carroll, Michael S; Weese-Mayer, Debra E

2013-03-01

233

Large-scale single incised valley from a small catchment basin on the western Adriatic margin (central Mediterranean Sea)  

NASA Astrophysics Data System (ADS)

The Manfredonia Incised Valley (MIV) is a huge erosional feature buried below the Apulian shelf, on the western side of the Adriatic margin. The incision extends more than 60 km eastward, from the Tavoliere Plain to the outer shelf, not reaching the shelf edge. High-resolution chirp sonar profiles allow reconstruction of the morphology of the incision and its correlation at regional scale. The MIV records a single episode of incision, induced by the last glacial-interglacial sea level fall that forced the rivers draining the Tavoliere Plain to advance basinward, reaching their maximum extent at the peak of the Last Glacial Maximum. The valley was filled during a relatively short interval of about 10,000 yr during the Late Pleistocene-Holocene sea level rise and almost leveled-off at the time of maximum marine ingression, possibly recording the short-term climatic fluctuations that occurred. The accommodation space generated by the lowstand incision was exploited during the following interval of sea level rise by very high rates of sediment supply that allowed the preservation of up to 45 m of valley fill. High-resolution chirp sonar profiles highlight stratal geometries that are consistent with a typical transgressive valley fill of an estuary environment, including bay-head deltas, central basin and distal barrier-island deposits, organized in a backstepping configuration. The highest complexity of the valley fill is reached in the shallowest and most proximal area, where a kilometric prograding wedge formed during a period dominated by riverine input, possibly connected to high precipitation rates. Based on the depth of the valley margins during this interval, the fill was likely isochronous with the formation of sapropel S1 in the Mediterranean region and may have recorded significant fluctuations within the hydrological cycle.

Maselli, Vittorio; Trincardi, Fabio

2013-01-01

234

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

USGS Publications Warehouse

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

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

2002-01-01

235

State-of-the-Art for Assessing Earthquake Hazards in the United States. Report 10. Attenuation of High-Frequency Seismic Waves in the Central Mississippi Valley.  

National Technical Information Service (NTIS)

This study was concerned with the attenuation of high-frequency earthquake waves in the central Mississippi valley. The data were obtained from seismographs which measured the vertical component of ground motion. Recording was on analog magnetic tape and ...

J. J. Dwyer O. W. Nuttli

1978-01-01

236

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

237

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

238

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

239

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

240

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

NASA Astrophysics Data System (ADS)

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

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

241

Ictal central apnea as a predictor for sudden unexpected death in epilepsy  

Microsoft Academic Search

Epidemiological evidence associating ictal hypoventilation during focal seizures with a heightened risk for subsequent sudden unexpected death in epilepsy (SUDEP) is lacking. We describe a patient with temporal lobe epilepsy with two focal seizures recorded in the epilepsy monitoring unit that were associated with central apnea lasting 57 and 58seconds. During these events, she demonstrated oxygen desaturation down to 68

Stephan U. Schuele; Mitra Afshari; Zahra S. Afshari; Michael P. Macken; Jorge Asconape; Lisa Wolfe; Elizabeth E. Gerard

2011-01-01

242

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

243

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  

Microsoft Academic Search

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

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

2007-01-01

244

Geochemical evidence of hydrothermal recharge in Lake Baringo, central Kenya Rift Valley  

NASA Astrophysics Data System (ADS)

Lake Baringo, a freshwater lake in the central Kenya Rift Valley, is fed by perennial and ephemeral rivers, direct rainfall, and hot springs on Ol Kokwe Island near the centre of the lake. The lake has no surface outlet, but despite high evaporation rates it maintains dilute waters by subsurface seepage through permeable sediments and faulted lavas. New geochemical analyses (major ions, trace elements) of the river, lake, and hot spring waters and the suspended sediments have been made to determine the main controls of lake water quality. The results show that evaporative concentration and the binary mixing between two end members (rivers and thermal waters) can explain the hydrochemistry of the lake waters.Two zones are recognized from water composition. The southern part of the lake near sites of perennial river inflow is weakly influenced by evaporation, has low total dissolved species (TDS), and has a seasonally variable load of mainly detrital suspended sediments. In contrast, waters of the northern part of the lake show evidence for strong evaporation (TDS of up to eight times inflow). Authigenic clay minerals and calcite may be precipitating from those more concentrated fluids.The subaerial hot-spring waters have a distinctive chemistry and are enriched in some elements that are also present in the lake water. Comparison of the chemical composition of the inflowing surface waters and lake water shows (1) an enrichment of some species (HCO3-, Cl, SO42-, F, Na, B, V, Cr, As, Mo, Ba and U) in the lake, (2) a depletion in SiO2 in the lake, and (3) a possible hydrothermal origin for most F. The rare earth element distribution and the F/Cl and Na/Cl ratios give valuable information on the rate of mixing of the river and hydrothermal fluids in the lake water. Calculations imply that thermal fluids may be seeping upward locally into the lake through grid-faulted lavas, particularly south of Ol Kokwe Island.

Tarits, Corinne; Renaut, Robin W.; Tiercelin, Jean-Jacques; Le Hérissé, Alain; Cotten, Jo; Cabon, Jean-Yves

2006-06-01

245

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

246

Adsorption studies of the herbicide simazine in agricultural soils of the Aconcagua valley, central Chile.  

PubMed

Simazine is a s-triazine herbicide that has been applied worldwide for agriculture. This herbicide is the second most commonly detected pesticide in surface and groundwater in the United States, Europe and Australia. In this study, simazine adsorption behaviour was studied in two agricultural soils of the Aconcagua valley, central Chile. The two studied soils were soil A (loam, 8.5% organic matter content) and soil B (clay-loam, 3.5% organic matter content). Three times higher simazine adsorption capacity was observed in soil A (68.03 mg kg(-1)) compared to soil B (22.03 mg kg(-1)). The simazine adsorption distribution coefficients (K(d)) were 9.32 L kg(-1) for soil A and 7.74 L kg(-1) for soil B. The simazine adsorption enthalpy in soil A was -21.0 kJ mol(-1) while in soil B the adsorption enthalpy value was -11.5 kJ mol(-1). These results indicate that simazine adsorption process in these soils is exothermic, governing H bonds the adsorption process of simazine in both the loam and clay-loam soils. These results and the potentiometric profiles of both soils, suggest that simazine adsorption in soil A is mainly governed by simazine-organic matter interactions and in soil B by simazine-clay interactions. The understanding of simazine sorption-desorption processes is essential to determine the pesticide fate and availability in soil for pest control, biodegradation, runoff and leaching. PMID:19101008

Flores, Cecilia; Morgante, Verónica; González, Myriam; Navia, Rodrigo; Seeger, Michael

2008-12-19

247

78 FR 21414 - Central Valley Project Improvement Act, Water Management Plans  

Federal Register 2010, 2011, 2012, 2013

...Valley Project Improvement Act, Water Management Plans AGENCY: Bureau of Reclamation...SUMMARY: The following Water Management Plans are available for review...the Criteria for Evaluating Water Management Plans (Criteria). For...

2013-04-10

248

Reconstructing the evolutionary history of an endangered subspecies across the changing landscape of the Great Central Valley of California.  

PubMed

Identifying historic patterns of population genetic diversity and connectivity is a primary challenge in efforts to re-establish the processes that have generated and maintained genetic variation across natural landscapes. The challenge of reconstructing pattern and process is even greater in highly altered landscapes where population extinctions and dramatic demographic fluctuations in remnant populations may have substantially altered, if not eliminated, historic patterns. Here, we seek to reconstruct historic patterns of diversity and connectivity in an endangered subspecies of woodrat that now occupies only 1-2 remnant locations within the highly altered landscape of the Great Central Valley of California. We examine patterns of diversity and connectivity using 14 microsatellite loci and sequence data from a mitochondrial locus and a nuclear intron. We reconstruct temporal change in habitat availability to establish several historical scenarios that could have led to contemporary patterns of diversity, and use an approximate Bayesian computation approach to test which of these scenarios is most consistent with our observed data. We find that the Central Valley populations harbour unique genetic variation coupled with a history of admixture between two well-differentiated species of woodrats that are currently restricted to the woodlands flanking the Valley. Our simulations also show that certain commonly used analytical approaches may fail to recover a history of admixture when populations experience severe bottlenecks subsequent to hybridization. Overall our study shows the strength of combining empirical and simulation analyses to recover the history of populations occupying highly altered landscapes. PMID:23106496

Matocq, Marjorie D; Kelly, Patrick A; Phillips, Scott E; Maldonado, Jesus E

2012-10-26

249

Seroprevalence of Hepatitis B and C Infections among Healthy Volunteer Blood Donors in the Central California Valley  

PubMed Central

Background/Aims The Central California Valley has a diverse population with significant proportions of Hispanics and Asians. This cross-sectional study was conducted to evaluate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in healthy blood donors in the Valley. Methods A total of 217,738 voluntary blood donors were identified between 2006 and 2010 (36,795 first-time donors; 180,943 repeat donors). Results Among the first-time donors, the HBV and HCV prevalence was 0.28% and 0.52%, respectively. Higher HBV prevalence seen in Asians (3%) followed by Caucasians (0.05%), African Americans (0.15%), and Hispanics (0.05%). Hmong had a HBV prevalence of 7.63% with a peak prevalence of 8.76% among the 16- to 35-year-old age group. Highest HCV prevalence in Native Americans (2.8) followed by Caucasians (0.59%), Hispanics (0.45%), African Americans (0.38%), and Asians (0.2%). Conclusions Ethnic disparities persist with regard to the prevalence of HBV and HCV in the Central California Valley. The reported prevalence may be an underestimate because our study enrolled healthy volunteer blood donors only. The development of aggressive public health measures to evaluate the true prevalence of HBV and HCV and to identify those in need of HBV and HCV prevention measures and therapy is critically important.

Atla, Pradeep R.; Ameer, Adnan; Sadiq, Humaira; Sadler, Patrick C.

2013-01-01

250

Hydrochemistry of the Mahomet Bedrock Valley Aquifer, East-Central Illinois: indicators of recharge and ground-water flow  

USGS Publications Warehouse

A conceptual model of the ground-water flow and recharge to the Mahomet Bedrock Valley Aquifer (MVA), east-central Illinois, was developed using major ion chemistry and isotope geochemistry. The MVA is a 'basal' fill in the east-west trending buried bedrock valley composed of clean, permeable sand and gravel to thicknesses of up to 61 m. It is covered by a thick sequence of glacial till containing thinner bodies of interbedded sand and gravel. Ground water from the MVA was found to be characterized by clearly defined geochemical regions with three distinct ground-water types. A fourth ground-water type was found at the confluence of the MVA and the Mackinaw Bedrock Valley Aquifer (MAK) to the west. Ground water in the Onarga Valley, a northeastern tributary of the MVA, is of two types, a mixed cation-SO42- type and a mixed cation-HCO3- type. The ground water is enriched in Na+, Ca2+, Mg2+, and SO42- which appears to be the result of an upward hydraulic gradient and interaction of deeper ground water with oxidized pyritic coals and shale. We suggest that recharge to the Onarga Valley and overlying aquifers is 100% from bedrock (leakage) and lateral flow from the MVA to the south. The central MVA (south of the Onarga Valley) is composed of relatively dilute ground water of a mixed cation-HCO3- type, with low total dissolved solids, and very low concentrations of Cl- and SO42-. Stratigraphic relationships of overlying aquifers and ground-water chemistry of these and the MVA suggest recharge to this region of the MVA (predominantly in Champaign County) is relatively rapid and primarily from the surface. Midway along the westerly flow path of the MVA (western MVA), ground water is a mixed cation-HCO3- type with relatively high Cl-, where Cl- increases abruptly by one to ??? two orders of magnitude. Data suggest that the increase in Cl- is the result of leakage of saline ground water from bedrock into the MVA. Mass-balance calculations indicate that approximately 9.5% of recharge in this area is from bedrock. Concentrations of Na+, HCO3-, As, and TDS also increase in the western MVA. Ground water in the MAK is of a Ca2+-HCO3- type. Mass-balance calculations, using Cl- as a natural, conservative tracer, indicate that approximately 17% of the ground water flowing from the confluence area is derived from the MVA.

Panno, S. V.; Hackley, K. C.; Cartwright, K.; Liu, C. L.

1994-01-01

251

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

252

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

NASA Astrophysics Data System (ADS)

Phreatomagmatic eruptions occur when rising magma encounters groundwater and/or surface water, causing a steam explosion and the ejection of country rock and pyroclastic material. The predominance of this type of activity at the Ubehebe volcanic field in northern Death Valley, California, is enigmatic owing to the extremely arid climate of the region. A novel application of 10Be surface exposure dating is presented to determine the timing of phreatomagmatic eruptions at Ubehebe Crater and to test the idea that volcanism may relate to a wetter than present hydro-climate. Twelve of the fifteen ages obtained lie between 0.8 and 2.1 ka, while three samples give older, mid-Holocene ages. The cluster between 0.8 and 2.1 ka is interpreted as encompassing the interval of volcanic activity during which Ubehebe Crater was formed. The remaining older ages are inferred to date eruptions at the older neighboring craters. The main and most recent period of activity encompasses the Medieval Warm Period, an interval of prolonged drought in the American southwest, as well as slightly wetter conditions prior to the Medieval Warm Period. Phreatomagmatic activity under varied hydrologic conditions casts doubt on the idea that eruptive timing relates to a wetter hydro-climate. Instead, the presence of a relatively shallow modern water table suggests that sufficient groundwater was generally available for phreatomagmatic eruptions at the Ubehebe site, in spite of prevailing arid conditions. This and the youth of the most recent activity suggest that the Ubehebe volcanic field may constitute a more significant hazard than generally appreciated.

Sasnett, Peri; Goehring, Brent M.; Christie-Blick, Nicholas; Schaefer, Joerg M.

2012-01-01

253

Give Me Equity or Give Me Death - The Role of Competition and Compensation in Building Silicon Valley  

Microsoft Academic Search

In this essay, I argue that the preeminence of Silicon Valley as an incubator of technology companies is attributable to equity compensation. Ronald Gilson, relying on the work of AnnaLee Saxenian and others who have noted the tendency of Silicon Valley employees to job hop, has suggested that California law prohibiting the enforcement of non-compete agreements was a major factor

Richard A. Booth

2006-01-01

254

Goats in resource-poor systems in the dry environments of West Asia, Central Asia and the Inter-Andean valleys  

Microsoft Academic Search

A review of goat production systems in harsh and dry environments of West Asia, Central Asia and the Inter-Andean valleys of Latin America reveals that while goats are an important component of a considerable number of vulnerable and resource-poor production systems, the production performance and potentials have not been sufficiently characterized nor documented. In West and Central Asia goats are

L. Iñiguez

2004-01-01

255

Diagenetic controls on primary and secondary porosity in valley-fill marine sandstones - Misener Formation, north-central Oklahoma  

SciTech Connect

The Devonian Misener formation in north-central Oklahoma consists of a series of discontinuous sandstone and shale bodies deposited in erosional topographic lows on the post-Hunton unconformity surface of north-central Oklahoma. Paleontological, mineralogical, and sedimentological evidence supports a marine valley-fill depositional setting including both channel and nonchannel facies. Abrupt changes in sandstone thickness and reservoir properties are characteristic of Misener sandstones. These sandstones were episodically deposited, fine upward and commonly interfinger with an equivalent shale facies. The basal contacts of the Misener sandstone bodies are erosional with the inclusion of shale, phosphate, and sandstone clasts in a medium-grained, dolomitic quartzarenite sandstone. A combination of primary and secondary porosity makes Misener sandstone reservoirs prolific hydrocarbon producers.

Prezbindowski, D.; Fritz, R.D.; Francis, B.M.

1989-03-01

256

Single-Station Passive Seismic Stratigraphy for the characterization of subsurface structure of the Valtellina valley (central Alps, northern Italy)  

NASA Astrophysics Data System (ADS)

The reconstruction of the subsurface structure of alpine valleys plays a key-role in the evaluation of their genesis, entrenchment and tectonic evolution. As a matter of fact, their characterization is strictly dependent on borehole data (water wells, shallow geognostic logs) and land based, deep seismic reflection/refraction lines; unfortunately, the availability of these datasets is often limited by economic and logistical limitations. In this work the subsurface structure of the Valtellina buried valley (central Alps, northern Italy) was investigated by the means of Single-Station Passive Seismic Stratigraphy (S-SPSS), which yields the 1D shear velocity (Vs) profiles, based on the Horizontal to Vertical Spectral Ratios (HVSR) of microtremors produced by Raleigh waves trapped in the ground and provided by measurements of the resonance frequencies produced by a layered seismic stratigraphy. The study area is the central part of Valtellina, W-E oriented along the Insubric line and drained by the Adda river. The sedimentary succession is known by shallow (

Mele, M.; Bini, A.; Bassi, S.; Giudici, M.; Monti, M.; Azzola, M.

2012-04-01

257

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

258

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

259

Habitat range of two alpine medicinal plants in a trans-Himalayan dry valley, Central Nepal  

Microsoft Academic Search

Understanding of the habitat range of threatened Himalayan medicinal plants which are declining in their abundance due to\\u000a high anthropogenic disturbances is essential for developing conservation strategies and agrotechnologies for cultivation.\\u000a In this communication, we have discussed the habitat range of two alpine medicinal plants, Aconitum naviculare (Brühl) Stapf and Neopicrorhiza scrophulariiflora (Pennel) Hong in a trans-Himalayan dry valley of

Bharat Babu Shrestha; Pramod Kumar Jha

2009-01-01

260

Valley-Fill Sandstones in the Kootenai Formation on the Crow Indian Reservation, South Central Montana.  

SciTech Connect

Subsurface data is being collected, organized, and a digital database is being prepared for the project. An ACCESS database and PC-Arcview will be used to manage and interpret the data. All of the four 30 X 60 geologic quadrangles have been scanned to produce a digital surface geologic data base for the Crow Reservation and all are nearing completion. Writing of the map explanations has begun. Field investigations were nearly completed during this quarter; only minor field checks remain. With the help of a student field assistant from the Crow Tribe, the entire project area was inventoried for the presence of valley-fill deposits in the Kootenai Formation. Field inventory has resulted in the identification of nine exposures of thick valley-fill deposits. These appear to represent at least four major westward-trending valley systems. All the channel localities have been measured and described in detail and paleocurrent data has been collected from all but one locality. In addition, two stratigraphic sections were measured in areas where channels are absent.

Lopez, D.A.

1997-10-01

261

Groundwater basin of the Tulum Valley, San Juan, Argentina: A morphohydrogeologic analysis of its central sector  

NASA Astrophysics Data System (ADS)

The geometry of a sector in the groundwater basin of the Tulum Valley has been studied to determine the shape, thickness, and vertical and horizontal distribution of the grain size, as well as the depositional environmental conditions of the Quaternary deposits that fill the valley. The geomorphologic features of the area have been investigated on the basis of aerial photographs checked with fieldwork. Three subsurface sections were prepared for a hydrogeological analysis of the area. These cross-sections were prepared by combining information from descriptions of well samples and interpretations of geophysical logs of wells and electric resistivity surveys. Within the studied area, the floor of the groundwater basin is asymmetrically shaped; the Quaternary deposits, which lie on an impervious or poorly pervious electrically conductive hydrogeologic basement of Late Tertiary age, reach a thickness of 670 m in the west and only 215 m in the eastern extreme. The Tulum Valley Basin is divided into two subbasins by a fault system trending NNE SSW, which plays an important role in the configuration of the basin and the distribution of the Quaternary sediments units, as well as the distribution of aquifers in the subsurface. The western subbasin has a thicker cover and coarser grain sizes than the eastern one, where the sediments have more fine-grained intercalations and hardpans. The latter are probably pedogenic in origin.

Lloret, Gustavo; Suvires, Graciela M.

2006-07-01

262

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

263

Estuarine fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution  

NASA Astrophysics Data System (ADS)

We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial incision-deposition. We suggest that several incision-aggradation phases may have occurred during glacial periods. Major aggradation events may overlap with cold episodes, while incision appears to concentrate on the warming limb of climate transitions. The complex stratigraphy of the Quaternary record in the Lower Tagus valley is influenced by repeated base-level and climate changes. This paper submits the first chronostratigraphic framework for valley fill deposits in the Lower Tagus area. Sea-level rise forced aggradation and controlled deposition of the fine-grained sedimentary wedge underlying the low-gradient Lower Tagus floodplain. Investigations have focused on the lower Muge tributary, where rapidly aggrading estuarine and fluvial environments were abruptly established (˜8150 cal BP) as sea level rose. Base level at the valley mouth controlled the upstream extent of the fine-grained backfill. Tidal environments disappeared abruptly (˜5800 cal BP) when the open estuary at the Muge confluence was infilled by the Tagus River. The decrease and final still stand of sea-level rise led to floodplain stabilisation with peat (˜6400 5200 cal BP) and soil formation (˜5200 2200 cal BP). Localised renewed sedimentation (˜2200 200 cal BP) is linked to human activity.

van der Schriek, Tim; Passmore, David G.; Rolão, Jose; Stevenson, Anthony C.

2007-11-01

264

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

265

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

266

Facies Analysis of Tertiary Basin-Filling Rocks of the Death Valley Regional Ground-Water System and Surrounding Areas, Nevada and California  

SciTech Connect

Existing hydrologic models of the Death Valley region typically have defined the Cenozoic basins as those areas that are covered by recent surficial deposits, and have treated the basin-fill deposits that are concealed under alluvium as a single unit with uniform hydrologic properties throughout the region, and with depth. Although this latter generalization was known to be flawed, it evidently was made because available geologic syntheses did not provide the basis for a more detailed characterization. As an initial attempt to address this problem, this report presents a compilation and synthesis of existing and new surface and subsurface data on the lithologic variations between and within the Cenozoic basin fills of this region. The most permeable lithologies in the Cenozoic basin fills are freshwater limestones, unaltered densely welded tuffs, and little-consolidated coarse alluvium. The least permeable lithologies are playa claystones, altered nonwelded tuffs, and tuffaceous and cl ay-matrix sediments of several types. In all but the youngest of the basin fills, permeability probably decreases strongly with depth owing to a typically increasing abundance of volcanic ash or clay in the matrices of the clastic sediments with increasing age (and therefore with increasing depth in general), and to increasing consolidation and alteration (both hydrothermal and diagenetic) with increasing depth and age. This report concludes with a categorization of the Cenozoic basins of the Death Valley region according to the predominant lithologies in the different basin fills and presents qualitative constraints on the hydrologic properties of these major lithologic categories.

Sweetkind, D.S.; Fridrich, C.J.; Taylor, Emily

2002-04-04

267

Visualizing and Analyzing Geologic and Hydrologic Models of the Death Valley Regional Ground-water Flow System, Nevada and California  

NASA Astrophysics Data System (ADS)

Numerical modeling of the Death Valley regional ground-water flow system, Nevada and California, involves the conceptualization and simulation of a complex and heterogeneous geologic and hydrologic system. The hydrogeologic characteristics of the region result from an arid climate and complex geology. Interbasin regional ground-water flow occurs through a thick Paleozoic carbonate-rock sequence, a locally thick Tertiary volcanic-rock sequence, and basin-fill alluvium. Throughout the system, deep and shallow ground-water flow may be controlled by extensive and pervasive faults and fractures. Understanding ground-water flow requires the formulation of conceptual and digital models that characterize the three-dimensional (3D) hydrogeologic framework within which the water moves. Part of this study includes the construction of a digital 3D geologic model that provides a description of the geometry and composition of the hydrogeologic units and structures that control ground-water flow. These hydrogeologic units and structures are then simulated in the hydrologic model using the Hydrogeologic Unit Flow (HUF) Package and the Horizontal-Flow Barrier (HFB) Package of the ground-water modeling code MODFLOW-2000. The HUF Package allows the geometry of the hydrogeologic units to be defined explicitly using hydrogeologic units that can be different from the defined flow-model layers. The HFB Package allows the simulation of features that retard flow. Likewise, zone and multiplication arrays can be utilized to incorporate hydraulic property detail, such as facies changes within a particular unit. Utilizing these capabilities significantly contributes to the ability of the modeler to better simulate the hydrogeologic conceptual model of the flow system. As geologic and hydrologic modeling software increase in complexity, modelers have the ability to better visualize and interact with the simulated hydrogeologic system and flow-model results. Post-processing utilities such as MODPATH and ZONEBUDGET allow the calculation of information helpful for analyzing the vast quantities of data. New and existing geographic information system (GIS) techniques can be used to visualize these results, such as flow paths and water-budget data, as well as water-level altitudes, hydrogeologic units, zone arrays, and flow-model layers. For example, three-dimensional views of particle paths along with the geometry of hydrogeologic units and structures provide insight into which features may be controlling ground-water flow paths. Employing GIS to develop maps of flux in and out of particular parts of the system aids in the visualization of the water budget. In addition, with the advent of the newer techniques and modeling tools the scientist can better explore the links between the hydrogeologic framework and the flow system. For instance, the scientist may conduct hypothesis testing regarding the hydraulic parameters associated with specific units or features based on visualizations analyses performed with the aid of GIS. Thus, the power of combining the GIS techniques and modeling packages is that, in addition to helping the scientist calibrate the ground-water model, it allows the scientist to test the degree to which the flow-model results match the conceptual model.

Faunt, C. C.; San Juan, C.

2003-12-01

268

Vivid valleys, pallid peaks? Hypsometric variations and rural-urban land change in the Central Peruvian Andes.  

PubMed

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. PMID:23564987

Haller, Andreas

2012-11-01

269

Geophysical and Geological Evidence of Neotectonic Deformation Along the Hovey Lake Fault, Lower Wabash Valley Fault System, Central United States  

NASA Astrophysics Data System (ADS)

High-resolution seismic (shear-wave) reflection profiles were collected over a segment of the Hovey Lake fault, a known Paleozoic fault within a system of faults in the southernmost Wabash River valley of the central United States. Although the system of faults, called the Wabash Valley fault system, lie in an area of recognized prehistoric and contemporary seismicity, their seismogenic potential remain poorly defined, however. Consequently, the objectives of this study were to assess the Hovey Lake fault, one of the more prominent fault strands in the system, for neotectonic reactivation, and if present, collect sediment samples for dateable material from the disrupted horizons to provide an age constraint for the movement. The resultant stacked profiles show high-angle deformation extending above the Paleozoic bedrock, and into Upper Quaternary sediment. Time displacement calculations from the data show approximately 10.5 m of offset on the top-of-bedrock horizon, and 2 m of inverted displacement along the earliest-arriving Quaternary soil reflector at a depth of 5 m. Preliminary correlative coring found organic material in a disrupted soil horizon located 7.7 m below ground surface. Subsequent carbon-14 testing of the deeper horizon allows us to place a maximum age constraint at this site of approximately 37,000 YBP.

Woolery, E. W.; Rutledge, F. A.; Wang, Z.

2004-12-01

270

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

271

Adapting to climate variability and change: experiences from cereal-based farming in the central rift and kobo valleys, ethiopia.  

PubMed

Small-holder farmers in Ethiopia are facing several climate related hazards, in particular highly variable rainfall with severe droughts which can have devastating effects on their livelihoods. Projected changes in climate are expected to aggravate the existing challenges. This study examines farmer perceptions on current climate variability and long-term changes, current adaptive strategies, and potential barriers for successful further adaptation in two case study regions-the Central Rift Valley (CRV) and Kobo Valley. The study was based on a household questionnaire, interviews with key stakeholders, and focus group discussions. The result revealed that about 99 % of the respondents at the CRV and 96 % at the Kobo Valley perceived an increase in temperature and 94 % at CRV and 91 % at the Kobo Valley perceived a decrease in rainfall over the last 20-30 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. PMID:23943096

Kassie, Belay Tseganeh; Hengsdijk, Huib; Rötter, Reimund; Kahiluoto, Helena; Asseng, Senthold; Van Ittersum, Martin

2013-08-14

272

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

273

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

274

California GAMA Special Study: An isotopic and dissolved gas investigation of nitrate source and transport to a public supply well in California's Central Valley  

Microsoft Academic Search

This study investigates nitrate contamination of a deep municipal drinking water production well in Ripon, CA to demonstrate the utility of natural groundwater tracers in constraining the sources and transport of nitrate to deep aquifers in the Central Valley. The goal of the study was to investigate the origin (source) of elevated nitrate and the potential for the deep aquifer

M J Singleton; J E Moran; B K Esser; S K Roberts; D J Hillegonds

2010-01-01

275

Pesticide risk management using indicators for vineyards in the central valley of Chile.  

PubMed

The Apalta catchment is a wine-producing area of 1300 ha, lying south of Santiago, located in the Colchagua Valley, near Santa Cruz in the VI Region of Chile. The vineyards are planted on slopes of up to 22 degrees, the rows being aligned mainly down the slope. This cropping system and its management lead to a potential contamination of natural resources. To assess the risk of environmental contamination due to the application of pesticides in different pest control strategies, indicators at a field level were derived according to a step-by-step procedure. Using these indicators, runoff was found to be the main process of impact. The different pest control strategies in this catchment caused different potential risks, though these in general were low. PMID:20050034

Nario, Adriana; Capri, Ettore; Balderacchi, Matteo; Pino, Inés; Parada, Ana María; Videla, Ximena; Luzio, Walter; Casanova, Manuel; Seguel, Oscar

2009-07-01

276

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

277

The effects of mountaintop mines and valley fills on the physicochemical quality of stream ecosystems in the central Appalachians: a review.  

PubMed

This review assesses the state of the science on the effects of mountaintop mines and valley fills (MTM-VF) on the physicochemical characteristics of streams in the central Appalachian coalfields of West Virginia, Kentucky, Virginia and Tennessee, USA. We focus on the impacts of mountaintop removal coal mining, which involves removing all - or some portion - of the top of a mountain or ridge to expose and mine one or more coal seams. Excess overburden is disposed in constructed fills in small valleys adjacent to the mining site. MTM-VF leachate persistently increases the downstream concentrations of major ions. Conductivity is a coarse measure of these ions, which are dominated by a distinct mixture of SO(4)(2-), HCO(3)(-), Ca(2+) and Mg(2+), that reflects their source, the oxidation of pyrite to form acid followed by neutralization of the acidity by carbonate minerals within the valley fills. This results in neutral to alkaline pHs, a range at which many metals are relatively insoluble. Other compounds within coal or overburden are solubilized and occur at elevated albeit lower concentrations, including K(+), Na(+), Cl(-), Se and Mn. In terms of physical characteristics, the valley fills act like headwater aquifers, baseflows increase in streams below valley fills and water temperatures exhibit reduced seasonal variation. Peak discharges may be increased in response to intense precipitation events, because of compaction of base surfaces of the MTM-VF areas, but newer approaches to reclamation reduce this compaction and may ameliorate these peak flows. Although the sedimentation pond is intended to capture fine particles that wash downstream from the valley fill, some studies found increased fine sediments in streams downstream from valley fills. However, a proportion of these fines may be eroded from stream banks rather than the valley fills. This is probably a result of the alterations in stream flows. PMID:22264919

Griffith, Michael B; Norton, Susan B; Alexander, Laurie C; Pollard, Amina I; LeDuc, Stephen D

2012-01-20

278

The Slow Death (Or Rebirth?) of Extended Star Formation in z ~ 0.1 Green Valley Early-type Galaxies  

NASA Astrophysics Data System (ADS)

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 ~ 0.1 drawn from the sample originally selected by Salim & 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 ?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.; Salim, Samir; Graves, Genevieve J.; Rich, R. Michael

2012-12-01

279

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

280

Quality of groundwater and surface water, Wood River Valley, south-central Idaho, July and August 2012  

USGS Publications Warehouse

Residents and resource managers of the Wood River Valley of south-central Idaho are concerned about the effects that population growth might have on the quality of groundwater and surface water. As part of a multi-phase assessment of the groundwater resources in the study area, the U.S. Geological Survey evaluated the quality of water at 45 groundwater and 5 surface-water sites throughout the Wood River Valley during July and August 2012. Water samples were analyzed for field parameters (temperature, pH, specific conductance, dissolved oxygen, and alkalinity), major ions, boron, iron, manganese, nutrients, and Escherichia coli (E.coli) and total coliform bacteria. This study was conducted to determine baseline water quality throughout the Wood River Valley, with special emphasis on nutrient concentrations. Water quality in most samples collected did not exceed U.S. Environmental Protection Agency standards for drinking water. E. coli bacteria, used as indicators of water quality, were detected in all five surface-water samples and in two groundwater samples collected. Some analytes have aesthetic-based recommended drinking water standards; one groundwater sample exceeded recommended iron concentrations. Nitrate plus nitrite concentrations varied, but tended to be higher near population centers and in agricultural areas than in tributaries and less populated areas. These higher nitrate plus nitrite concentrations were not correlated with boron concentrations or the presence of bacteria, common indicators of sources of nutrients to water. None of the samples collected exceeded drinking-water standards for nitrate or nitrite. The concentration of total dissolved solids varied considerably in the waters sampled; however a calcium-magnesium-bicarbonate water type was dominant (43 out of 50 samples) in both the groundwater and surface water. Three constituents that may be influenced by anthropogenic activity (chloride, boron, and nitrate plus nitrite) deviate from this pattern and show a wide distribution of concentrations in the unconfined aquifer, indicating possible anthropogenic influence. Time-series plots of historical water-quality data indicated that nitrate does not seem to be increasing or decreasing in groundwater over time; however, time-series plots of chloride concentrations indicate that chloride may be increasing in some wells. The small amount of temporal variability in nitrate concentrations indicates a lack of major temporal changes to groundwater inputs.

Hopkins, Candice B.; Bartolino, James R.

2013-01-01

281

Deep-currents along a rift valley of Central Indian Ridge observed by AUV "r2D4"  

NASA Astrophysics Data System (ADS)

In December 2006, the Institute of Industrial Science made geological and chemical investigation along rift valleys off the Rodriguez Island in the Central Indian Ridge with an AUV "gr2D4"h and found hydrothermal activities in one of the valleys, named the Great Dodo Lava Plain (water depth of approximately 2700m). In this present study, based on the AUV"fs navigation data taken from the investigation, we figured out the distribution of deep-currents in the Great Dodo Lava Plain and analyzed those currents and their relations with the tidal current and water-mass property. For current velocity, we used water-tracking velocity data measured by the Doppler Velocity Log (DVL) at a layer under the AUV. When the AUV was close to the sea bed, the velocity was adjusted to the absolute current velocity with bottom-tracking velocity measured by the DVL. When the bottom-tracking velocity was not available, the velocity was adjusted with AUV"fs velocity measured by the Inertial Navigation System. The adjusted current velocity data in the Great Dodo Lava Plain were observed for 6.5-hours in the range of 18.32°S-18.45°S, 65.28°E-65.37°E, and most of them reached 20 cm s-1 or more. The direction of the currents is between northwest and northeast, which almost corresponds to the direction of the valley"fs extension (north-northwest). The observed current speed is much higher than the tidal current speed predicted from a barotropic tidal model (< 3 cm s-1), but its meridional velocity component is stronger than the zonal component as well as the observed velocity. The predicted tidal current velocity shows semi-diurnal period, and that is also the case in the observed meridional velocity component. Thus, it is expected that the deep-currents and tidal currents are influenced by the bottom topography extending north-northwestward. For error consideration, we compared near-surface current velocities measured by the AUV and by the shipboard acoustic Doppler velocity profiler of the parent vessel. Then, the directions roughly correspond although the current speed measured by the AUV is rather low. This might be because bottom-tracking data measured by the DVL were not available at near-surface. In our presentation, we will also show the analysis in terms of water-mass properties and the other results from the data measured in the Mariana Trough in May 2004 and in the Izu-Ogasawara Island Arc in August 2005.

Komaki, K.; Ura, T.; Nagahashi, K.; Tamaki, K.

2008-12-01

282

Cardiospecificity of the 3 rd generation cardiac troponin T assay during and after a 216 km ultra-endurance marathon run in Death Valley  

Microsoft Academic Search

Background\\u000a   The reasons\\u000a for the appearance of cardiacspecific\\u000a troponin (cTnT) after\\u000a strenuous exercise are unclear. The\\u000a aim of the present study was to\\u000a evaluate the cardiospecificity of the\\u000a 3rd generation cardiac cTnT assay\\u000a during and after an ultra-endurance\\u000a race of 216 km at extreme\\u000a environmental conditions in Death\\u000a Valley.\\u000a \\u000a \\u000a \\u000a \\u000a Study design and methods\\u000a   We measured serially cTnT, creatine\\u000a kinase (CK),

H. J. Roth; R. M. Leithäuser; H. Doppelmayr; M. Doppelmayr; H. Finkernagel; S. P. von Duvillard; S. Korff; H. A. Katus; Evangelos Giannitsis; R. Beneke

2007-01-01

283

A Modified Method for Saline Lake Calcite Isotope Analysis: Application to a Study of Climate Change over 200,000 Years in Death Valley, California.  

NASA Astrophysics Data System (ADS)

The standard method of oxygen and carbon isotope analyses for carbonate minerals was first reported by McCrea (1950). Carbonates are converted to CO2 by the reaction of carbonates with 100% phosphoric acid at temperatures between 25 and 95° C for C- and O-isotope analyses: 3CaCO3 + 2H3PO4 = 3CO2 + 3H2O + Ca3(PO4)2 The reaction time for this method can vary depending on different minerals and temperature. For example, at room temperature, the reaction time could be an hour or less for calcite and aragonite, three days for dolomite, two weeks for magnesite, and several months for siderite. This method is very reliable for almost every carbonate-dominated sample or even trace carbonates in silicate rocks. However, Death Valley saline core sediments showed that this standard method could be problematic for chloride-rich or soluble sulfate-rich carbonate samples because of the production of SO2 and/or HCl gas by partial reaction of the chloride or sulfate minerals with 100% H3PO4. The SO2 and HCl gases can affect the ? -values significantly in two ways: (1) The contaminating gases may react with the CO2 in the mass spectrometer source region, isotopically fractionating the CO2 and/or generating background peaks in the CO2 + spectrum; and (2) The SO2 and HCl may react with interior parts of the mass spectrometer reducing its stability and/or sensitivity. In this study, we choose 85% H3PO4 to react with the lacustrine calcite at room temperature by off-line "Y" tube preparation for 2 to 3 minutes. This modification to the traditional method has resulted in negligible SO2 and HCl production. The CO2 gas generated from each bulk lacustrine sediment sample was manually introduced into a VG 609 mass spectrometer for C and O isotope analyses. The analytical precision is better than ±0.2‰ for both ? 13C and ? 18O. This modification of the method of McCrea (1950) was applied to determining carbon and oxygen isotopic compositions of lacustrine calcite in bulk saline lake sediments. For a continuous 200,000-year ? 18O record of lacustrine calcite from a 186-meter sediment core from Badwater Basin, Death Valley, California, a two-level climatic fluctuation model is suggested.. This record provides new insight to the debate on the timing and driving forces of late Quaternary paleoclimatic changes. Excursions in calcite ? 18O are similar to those of ? 18O in sulfate in the Death Valley core, as well as to those in marine carbonate (SPECMAP) and polar ice in the Summit ice core (GRIP), Greenland. The Death Valley record shows periodicities of 96000, 39000, 21000, 14000 and 8000 years. The longer-term (96000, 39000 & 21000 years) fluctuations match Milankovitch orbital forcing, and are thus likely to be global in origin; the shorter-term (14000 and 8000 years) fluctuations probably reflect regional climatic and/or hydrologic forcing.

Yang, W.; Lowenstein, T. K.; Krouse, R. H.; Spencer, R. J.; Ku, T.

2004-12-01

284

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

285

Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies. LANDSAT TM investigation proposal TM-019  

NASA Astrophysics Data System (ADS)

Processing and interpretation of Thematic Mapper (TM) data, extensive field work, and processing of SPOT data were continued. Results of these analyses led to the testing and rejecting of several of the geologic/tectonic hypotheses concerning the continuation of the Garlock Fault Zone (GFZ). It was determined that the Death Valley Fault Zone (DVFZ) is the major through-going feature, extending at least 60 km SW of the Avawatz Mountains. Two 5 km wide fault zones were identified and characterized in the Soda and Bristol Mountains, forming a continuous zone of NW trending faulting. Geophysical measurements indicate a buried connection between the Avawatz and the Soda Mountains Fault Zone. Future work will involve continued field work and mapping at key locations, further analyses of TM data, and conclusion of the project.

Abrams, Michael; Verosub, Ken

286

EVOLUTION OF POLASKIA CHICHIPE (CACTACEAE) UNDER DOMESTICATION IN THE TEHUACAN VALLEY, CENTRAL MEXICO: REPRODUCTIVE BIOLOGY1  

Microsoft Academic Search

Polaskia chichipe, a columnar cactus, is cultivated for its edible fruits in central Mexico. This study analyzed whether artificial selection has modified its reproduction patterns and caused barriers to pollen exchange between wild, managed in situ, and cultivated populations. Anthesis was diurnal (;16 h in winter, ;10 h in spring) as well as partly nocturnal (;12 h in winter, ;3

ADRIANA OTERO-ARNAIZ; A LEJANDRO CASAS; CARMEN BARTOLO

287

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

288

Co-evolution of soils and vegetation in the Aísa Valley Experimental Station (Central Pyrenees)  

NASA Astrophysics Data System (ADS)

Soils and vegetation tend to evolve jointly in relation to climate evolution and the impacts of human activity. This study analyzes soil and vegetation characteristics under various plant covers, using information from the Aísa Valley Experimental Station (AVES), Spanish Pyrenees, from 1991 to 2010. The land uses considered were: dense shrub cover, grazing meadow, abandoned field, cereal (barley), abandoned shifting agriculture, active shifting agriculture, burnt1 and burnt2 plots, and in-fallow plot. All the plots were installed on a field abandoned 45 years ago. Some of the plots did not change in plant cover through the study period (e.g., the meadow, cereal and shifting agriculture plots), but others underwent changes in density and composition, such as: (i) The dense shrub cover plot represents the natural evolution of the abandoned field. When the AVES was equipped, this plot was completely dominated by Genista scorpius, with a few stands of Rosa gr. Canina. Twenty years later, Genista scorpius is affected of senescence and shows almost no regeneration capacity. (ii) The abandoned field had previously been cultivated with cereals until 1993. Once abandoned, the progression of plant colonization was very rapid. Firstly with grasses and, 10 years later, with Genista scorpius. At present, this latter occupies more than 50% of the plot. (iii) The evolution of plant colonization in the abandoned shifting agriculture plot was slower than that in the 'normal' abandoned field, mainly because of the differences in fertilization when they were cultivated. (iv) One of the burnt plots evolved from 0% to a coverage of almost 100% in a shot period, whereas the other plot remained with a shrub density of about 60% several years after the fire. Soil samples (superficial and depth) were analyzed to obtain physical and chemical properties: structure, texture, pH, CaCO3, Organic Matter and various anions and cations. The main purpose was to detect differences in the soil properties as a consequence of land cover/land uses.

Serrano Muela, Maria Pilar; Nadal Romero, Estela; Lasanta, Teodoro; María García Ruiz, José

2013-04-01

289

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

290

Studies of geology and hydrology in the Basin and Range province, southwestern United States, for isolation of high-level radioactive waste-characterization of the Death Valley region, Nevada and California  

Microsoft Academic Search

The Death Valley region, Nevada and California, in the Basin and Range province, is an area of about 80,200 sq km located in southern Nevada and southeastern California. Precambrian metamorphic and intrusive basement rocks are overlain by a thick section of Paleozoic clastic and evaporitic sedimentary rocks. Mesozoic and Cenozoic rocks include extrusive and intrusive rocks and clastic sedimentary rocks.

M. S. Bedinger; K. A. Sargent; W. H. Langer

1989-01-01

291

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

292

Central sympathetic blockade ameliorates brain death-induced cardiotoxicity and associated changes in myocardial gene expression  

Microsoft Academic Search

Objective: Brain death results in cardiac injury and hemodynamic instability. After brain death, catecholamine levels surge in concert with increased expression of select myocardial gene products. Sympathetic blockade was used to investigate the effects of the adrenergic nervous system on myocardial gene expression in a rabbit model of brain death.Methods: A balloon expansion model of brain death in rabbits (n

Thomas Yeh; Andrew S. Wechsler; Laura Graham; Kathryn E. Loesser; Domenic A. Sica; Luke Wolfe; Emma R. Jakoi

2002-01-01

293

Programmed cell death in type II neuroblast lineages is required for central complex development in the Drosophila brain  

PubMed Central

Background The number of neurons generated by neural stem cells is dependent upon the regulation of cell proliferation and by programmed cell death. Recently, novel neural stem cells that amplify neural proliferation through intermediate neural progenitors, called type II neuroblasts, have been discovered, which are active during brain development in Drosophila. We investigated programmed cell death in the dorsomedial (DM) amplifying type II lineages that contribute neurons to the development of the central complex in Drosophila, using clonal mosaic analysis with a repressible cell marker (MARCM) and lineage-tracing techniques. Results A significant number of the adult-specific neurons generated in these DM lineages were eliminated by programmed cell death. Programmed cell death occurred during both larval and pupal stages. During larval development, approximately one-quarter of the neuronal (but not glial) cells in the lineages were eliminated by apoptosis before the formation of synaptic connectivity during pupal stages. Lineage-tracing experiments documented the extensive contribution of intermediate neural progenitor-containing DM lineages to all of the major modular substructures of the adult central complex. Moreover, blockage of apoptotic cell death specifically in these lineages led to prominent innervation defects of DM-derived neural progeny in the major neuropile substructures of the adult central complex. Conclusions Our findings indicate that significant neural overproliferation occurs normally in type II DM lineage development, and that elimination of excess neurons in these lineages through programmed cell death is required for the formation of correct neuropile innervation in the developing central complex. Thus, amplification of neuronal proliferation through intermediate progenitors and reduction of neuronal number through programmed cell death operate in concert in type II neural stem-cell lineages during brain development.

2012-01-01

294

The Antarctic viewpoint of the Central Paratethys: cause, timing, and duration of a deep valley incision in the Middle Miocene Alpine-Carpathian Foredeep of Lower Austria  

NASA Astrophysics Data System (ADS)

Global, glacio-eustatic sea-level changes massively influenced the depositional history of the Central Paratethyan region. Here, we correlate Middle Miocene global ?18O-shifts with ice volume changes on Antarctica and sea-level changes with corresponding phases of erosion (valley incision) and deposition in the Lower Austrian part of the Alpine-Carpathian Foredeep. This allows the exact dating of the valley formation. Two periods of positive ?18O-shifts resulted in sea-level drops of about 60 and 40 m, respectively. The first drop in the late Langhian (middle Badenian) at c. 13.9 Ma (Mi3b) was fast and caused severe erosion on the emerged foredeep. In a second, less pronounced step around 13.0 Ma (Mi4) in the middle Serravallian (late Badenian), the base level was further deepened after a period of alternating erosion and deposition. The combined sea-level change (80-120 m) fits well with the maximum thickness of Sarmatian sediments drilled within incised valley (110 m). The global sea-level falls affected not only the geological history of the foredeep. The intensive erosion (valley incision) is combined with delta progradation in the adjacent Vienna Basin. Due to this massive sea-level drop, the interruption of marine connections resulted in vast salt deposits and faunal crises within the Central Paratethys during this time.

Gebhardt, Holger; Roetzel, Reinhard

2013-06-01

295

Water transfer and major environmental provisions of the Central Valley Project Improvement Act: A preliminary economic evaluation  

NASA Astrophysics Data System (ADS)

Increasing block water pricing, water transfer, and wildlife refuge water supply provisions of the Central Valley Project (CVP) Improvement Act are analyzed in terms of likely farmer response and economic efficiency of these provisions. Based on a simplified partial equilibrium analysis, we estimate small, but significant water conservation savings due to pricing reform, the potential for substantial water transfers to non-CVP customers in severe drought years when the water price exceeds 110 per acre foot (1 acre foot equals 1.234 × 103 m3) and positive net benefits for implementation of the wildlife refuge water supply provisions. The high threshold water price is partly a result of requiring farmers to pay full cost on transferred water plus a surcharge of 25 per acre foot if the water is transferred to a non-CVP user. The act also sets an important precedent for water pricing reform, water transfer provisions, and environmental surcharges on water users that may find their way to other Bureau of Reclamation projects.

Loomis, John B.

1994-06-01

296

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

297

Poisoning deaths in Central China (Hubei): A 10-year retrospective study of forensic autopsy cases.  

PubMed

A retrospective study of autopsy cases was conducted at the Department of Forensic Medicine, Tongji Medical College (DFM-TMC), in Hubei, China to describe the characteristics of poisoning deaths from 1999 to 2008. A total of 212 poisoning deaths were investigated by DFM-TMC during the 10-year period. The poisoning deaths ranged from 17 cases in 1999 to 27 cases in 2008. Of the 212 cases, 82 deaths (38.7%) were from pesticides, 36 deaths (17.0%) from carbon monoxide, 34 deaths (16.0%) from drugs, 22 deaths (10.4%) from alcohol, 17 deaths (8.0%) from other chemicals, 15 deaths (7.1%) from poisonous plants and animals, and six deaths (2.8%) from heavy metals. Of the 82 pesticide poisoning deaths, 43 (52.4%) cases were caused by rodenticides, mainly tetramine (N = 39). The majority of poisoning deaths were accidents (63.7%), followed by suicides (25.9%) and homicides (3.8%). The manner of death could not be determined in 14 cases (6.6%). PMID:21198624

Zhou, Lan; Liu, Liang; Chang, Lin; Li, Ling

2010-12-13

298

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

Microsoft Academic Search

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°N., long 115°W and lat 38°N., long 118°W and encompasses the Death

C. C. Faunt; A. K. Turner; M. C. Hill

1997-01-01

299

West African and Amerindian ancestry and risk of myocardial infarction and metabolic syndrome in the Central Valley population of Costa Rica  

Microsoft Academic Search

Genetic ancestry and environmental factors may contribute to the ethnic differences in risk of coronary heart disease (CHD),\\u000a metabolic syndrome (MS) or its individual components. The population of the Central Valley of Costa Rica offers a unique opportunity\\u000a to assess the role of genetic ancestry in these chronic diseases because it derived from the admixture of a relatively small\\u000a number

Edward A. Ruiz-Narváez; Lance Bare; Andre Arellano; Joseph Catanese; Hannia Campos

2010-01-01

300

Mitochondrial DNA Haplotype Diversity in Apparent XY Female Fall-Run and Spring-Run Chinook Salmon in California's Central Valley  

Microsoft Academic Search

Mitochondrial DNA (mtDNA) haplotype diversity between putative XY females and genetically normal females of fall- and spring-run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley were compared to ascertain whether or not a subset of mtDNA haplotypes are unique to putative XY females. Two Y-chromosome markers, OtY1 and growth hormone pseudogene (GH-?), were used to screen spring Chinook salmon collected

Kevin S. Williamson; Bernie May

2007-01-01

301

Brainstem auditory evoked potentials in syndromes of decerebration, the bulbar syndrome and in central death.  

PubMed

The results are reported of serial brainstem auditory evoked potentials recordings in 51 patients with decerebration and bulbar syndrome. In contrast to the stability of latencies of single components of the potential in healthy subjects, patients with decerebration syndromes show considerable instability and an increase in the latency of all the components of the potential. In 34 decerebrate patients the P-I latency and the interpeak latencies for the medullo-pontine and ponto-mesencephalic segments as well as the central conduction time were significantly increased. There was marked reduction of the amplitude of P-V and P-III and deformation of the single components of the potential with widening and smoothing. The amplitude ratios A-V to A-I and A-III to A-I were significantly decreased. The findings are interpreted as due to mesencephalic and pontine functional disturbance during decerebration. The brainstem auditory evoked potential can be used to estimate the time of brain death. Possible causes of misinterpretation are discussed. PMID:6183408

Klug, N

1982-01-01

302

Evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacan Valley, central Mexico: reproductive biology.  

PubMed

Polaskia chichipe, a columnar cactus, is cultivated for its edible fruits in central Mexico. This study analyzed whether artificial selection has modified its reproduction patterns and caused barriers to pollen exchange between wild, managed in situ, and cultivated populations. Anthesis was diurnal (?16 h in winter, ?10 h in spring) as well as partly nocturnal (?12 h in winter, ?3 h in spring), and flowers were pollinated by bees, hummingbirds, and hawk moths. Manual cross-pollination was ?37-49% effective in all populations. Self-pollination was ?12% successful in the wild, but twice as successful (?22-27%) in managed and cultivated populations. Diurnal pollination was ?35-55% effective in winter and 100% in spring. Nocturnal pollination was successful only in winter (15%). Crosses among individuals were more effective within populations than among populations, including populations under a similar management regimen. The least successful crosses were between wild and cultivated populations. Flowers were produced in all populations from January to March, but flowering peaks differed by 1 mo among wild, managed, and cultivated populations and by 2 mo between wild and cultivated populations. The latter interrupted pollen exchange in May. Seeds from managed and cultivated populations germinated faster than those from wild individuals. Domestication has seemingly favored self-compatible P. chichipe plants with higher fruit yield, a longer period of fruit production, and faster seed germination, attributes that have resulted in partial reproductive barriers between wild and manipulated populations. PMID:21659154

Otero-Arnaiz, Adriana; Casas, Alejandro; Bartolo, Carmen; Pérez-Negrón, Edgar; Valiente-Banuet, Alfonso

2003-04-01

303

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

304

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

305

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

PubMed

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. PMID:17537917

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

2007-05-30

306

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

307

Heritability of Cognitive Functions in Families of Successful Cognitive Aging Probands from the Central Valley of Costa Rica  

PubMed Central

We sought to identify cognitive phenotypes for family/genetic studies of successful cognitive aging (SCA; maintaining intact cognitive functioning while living to late old age).We administered a battery of neuropsychological tests to nondemented nonagenarians (n = 65; mean age = 93.4±3.0) and their offspring (n = 188; mean age = 66.4±5.0) from the Central Valley of Costa Rica. After covarying for age, gender, and years of education, as necessary, heritability was calculated for cognitive functions at three pre-defined levels of complexity: specific neuropsychological functions (e.g., delayed recall, sequencing), three higher level cognitive domains (memory, executive functions, attention), and an overall neuropsychological summary. The highest heritability was for delayed recall (h2 = 0.74, se = 0.14, p < 0.0001) but significant heritabilities involving memory were also observed for immediate recall (h2 = 0.50), memory as a cognitive domain (h2 = 0.53), and the overall neuropsychological summary (h2 = 0.42). Heritabilities for sequencing (h2 = 0.42), fluency (h2 = 0.39), abstraction (h2 = 0.36), and the executive functions cognitive domain (h2 = 0.35) were also significant. In contrast, the attention domain and memory recognition were not significantly heritable in these families. Among the heritable specific cognitive functions, a strong pleiotropic effect (i.e., evidence that these may be influenced by the same gene or set of genes) for delayed and immediate recall was identified (bivariate statistic = 0.934, p < 0.0001) and more modest but significant effects were found for four additional bivariate relationships. The results support the heritability of good cognitive function in old age and the utilization of several levels of phenotypes, and they suggest that several measures involving memory may be especially useful for family/genetic studies of SCA.

Greenwood, Tiffany A.; Beeri, Michal S.; Schmeidler, James; Valerio, Daniel; Raventos, Henriette; Mora-Villalobos, Lara; Camacho, Karla; Carrion-Baralt, Jose R.; Angelo, Gary; Almasy, Laura; Sano, Mary; Silverman, Jeremy M.

2012-01-01

308

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

309

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

310

Methods, quality assurance, and data for assessing atmospheric deposition of pesticides in the Central Valley of California  

USGS Publications Warehouse

The U.S. Geological Survey monitored atmospheric deposition of pesticides in the Central Valley of California during two studies in 2001 and 2002–04. The 2001 study sampled wet deposition (rain) and storm-drain runoff in the Modesto, California, area during the orchard dormant-spray season to examine the contribution of pesticide concentrations to storm runoff from rainfall. In the 2002–04 study, the number and extent of collection sites in the Central Valley were increased to determine the areal distribution of organophosphate insecticides and other pesticides, and also five more sample types were collected. These were dry deposition, bulk deposition, and three sample types collected from a soil box: aqueous phase in runoff, suspended sediment in runoff, and surficial-soil samples. This report provides concentration data and describes methods and quality assurance of sample collection and laboratory analysis for pesticide compounds in all samples collected from 16 sites. Each sample was analyzed for 41 currently used pesticides and 23 pesticide degradates, including oxygen analogs (oxons) of 9 organophosphate insecticides. Analytical results are presented by sample type and study period. The median concentrations of both chloryprifos and diazinon sampled at four urban (0.067 micrograms per liter [?g/L] and 0.515 ?g/L, respectively) and four agricultural sites (0.079 ?g/L and 0.583 ?g/L, respectively) during a January 2001 storm event in and around Modesto, Calif., were nearly identical, indicating that the overall atmospheric burden in the region appeared to be fairly similar during the sampling event. Comparisons of median concentrations in the rainfall to those in the McHenry storm-drain runoff showed that, for some compounds, rainfall contributed a substantial percentage of the concentration in the runoff; for other compounds, the concentrations in rainfall were much greater than in the runoff. For example, diazinon concentrations in rainfall were about 70 percent of the diazinon concentration in the runoff, whereas the chlorpyrifos concentration in the rain was 1.8 times greater than in the runoff. The more water-soluble pesticides—carbaryl, metolachlor, napropamide, and simazine—followed the same pattern as diazinon and had lower concentrations in rain compared to runoff. Similar to chlorpyrifos,compounds with low water solubilities and higher soil-organic carbon partition coefficients, including dacthal, pendimethalin, and trifluralin, were found to have higher concentrations in rain than in runoff water and were presumed to partition to the suspended sediments and organic matter on the ground. During the 2002–04 study period, the herbicide dacthal had the highest detection frequencies for all sample types collected from the Central Valley sites (67–100 percent). The most frequently detected compounds in the wet-deposition samples were dacthal, diazinon, chlorpyrifos, and simazine (greater than 90 percent). The median wet-deposition amounts for these compounds were 0.044 micrograms per square meter per day (?g/m2/day), 0.209 ?g/m2/day, 0.079 ?g/m2/day, and 0.172 ?g/m2/day, respectively. For the dry-deposition samples, detection frequencies were greater than 73 percent for the compounds dacthal, metolachor, and chlorpyrifos, and median deposition amounts were an order of magnitude less than for wet deposition. The differences between wet deposition and dry deposition appeared to be closely related to the Henry’s Law (H) constant of each compound, although the mass deposited by dry deposition takes place over a much longer time frame. Pesticides detected in rainfall usually were detected in the aqueous phase of the soil-box runoff water, and the runoff concentrations were generally similar to those in the rainfall. For compounds detected in the aqueous phase and suspended-sediment samples of soil-box runoff, concentrations of pesticides in the aqueous phase generally were detected in low concentrations and had few corresponding detections in the suspended- sediment samples. Dacthal, diazinon, c

Zamora, Celia; Majewski, Michael S.; Foreman, William T.

2013-01-01

311

Tectonic Setting of the Gravity Fault and Implications for Ground-Water Resources in the Death Valley Region, Nevada and California  

NASA Astrophysics Data System (ADS)

The Amargosa trough, extending south from Crater Flat basin to the California-Nevada state line, is believed to be a transtensional basin accommodated in part by strike-slip displacement on the northwest-striking State Line fault and normal displacement on the north-striking Gravity fault. The Gravity fault, lying along the eastern margin of the Amargosa trough, was first recognized in the 1970s on the basis of correlations between gravity anomalies and a prominent spring line in Amargosa Valley. The Gravity fault causes an inflection in water-table levels, similar to other (but not all) normal faults in the area. Pools along the spring line, some of which lie within Death Valley National Park and Ash Meadows Wildlife Refuge, include endemic species potentially threatened by increasing agricultural activities in Amargosa Valley immediately to the west, where water tables are declining. Most of the springs and pools lie east of the Gravity fault, however, and it is important to understand the role that the Gravity fault plays in controlling ground-water flow. We have conducted a variety of geophysical investigations at various scales to better understand the tectonic framework of the Amargosa Desert and support new ground-water-flow models. Much of our focus has been on the tectonic interplay of the State Line, Gravity, and other faults in the area using gravity, ground-magnetic, audiomagnetotelluric (AMT), and time-domain electromagnetic (TEM) surveys. With 1250 new gravity measurements from Ash Meadows and Stewart Valley, we have developed a revised three-dimensional crustal model of the Amargosa trough constrained by well information and geologic mapping. The model predicts approximately 2 km of vertical offset on the Gravity fault but also suggests a complex structural framework. The fault is conventionally seen as a simple, down-to-the-west normal fault juxtaposing permeable pre-Tertiary carbonate rocks to the east against less permeable Tertiary sediments to the west. The new gravity inversion indicates a more complex footwall: some springs, for example, are associated with a concealed ridge or horst, with a secondary basin lying to the east. Six ground-magnetic transects across the Gravity fault using a truck- towed magnetometer show a characteristic magnetic anomaly reflecting different magnetic properties in rocks east and west of the fault. Ground-magnetic measurements, interpreted in conjunction with existing aeromagnetic data, allow us to map the shallow aspects of the Gravity fault and other faults in Ash Meadows in detail. Three TEM transects across the Gravity fault showed no strong evidence of a faulted contact, although depth of penetration may have been insufficient to reach associated resistivity contrasts. An AMT transect, however, shows a narrow zone of high resistivity directly along the Gravity fault. Although other interpretations are possible, this resistivity anomaly may reflect carbonate-rich cementation along the fault plane, possibly contributing to its influence on ground-water flow.

Blakely, R. J.; Sweetkind, D. S.; Faunt, C. C.; Jansen, J. R.; McPhee, D. K.; Morin, R. L.

2007-12-01

312

Methods for Using Ground-Water Model Predictions to Guide Hydrogeologic Data Collection, with Applications to the Death Valley Regional Ground-Water Flow System  

SciTech Connect

Calibrated models of ground-water 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 that 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, which includes the effects of parameter correlation in addition to individual parameter uncertainty and prediction sensitivity. The PSS and VOII methods are demonstrated using a model of the Death Valley regional ground-water 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.

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

2001-07-31

313

Preliminary evaluation of the importance of existing hydraulic-head observation locations to advective-transport predictions, Death Valley regional flow system, California and Nevada  

SciTech Connect

When a model is calibrated by nonlinear regression, calculated diagnostic statistics and measures of uncertainty provide a wealth of information about many aspects of the system. This report presents a method of ranking the likely importance of existing observation locations using measures of prediction uncertainty. It is suggested that continued monitoring is warranted at more important locations, and unwarranted or less warranted at less important locations. The report develops the methodology and then demonstrates it using the hydraulic-head observation locations of a three-layer model of the Death Valley regional flow system (DVRFS). The predictions of interest are subsurface transport from beneath Yucca Mountain and 14 underground Test Area (UGTA) sites. The advective component of transport is considered because it is the component most affected by the system dynamics represented by the regional-scale model being used. The problem is addressed using the capabilities of the U.S. Geological Survey computer program MODFLOW-2000, with its ADVective-Travel Observation (ADV) Package, and an additional computer program developed for this work.

Hill, M.C.; Ely, D.M.; Tiedeman, C.R.; O'Brien, G.M.; D'Agnese, F.A.; Faunt, C.C.

2001-08-01

314

Formerly-aragonite seafloor fans from Neoproterozoic strata, Death Valley and southeastern Idaho, United States: Implications for "cap carbonate" formation and snowball Earth  

NASA Astrophysics Data System (ADS)

Seafloor-precipitated calcium carbonate fans, exceedingly rare in post-Paleoproterozoic time, make a dramatic reappearance in the post-glacial cap carbonates associated with Neoproterozoic low latitude glaciation (snowball Earth). Their presence is commonly interpreted to indicate elevated seawater alkalinity; the source of the anomalous alkalinity has been a critical, much-debated component in competing "snowball Earth" hypotheses. Two new Neoproterozoic seafloor fan occurrences have been reported recently in the Western United States (Death Valley and southeastern Idaho). Each were deposited during transgression and record negative ?13C values as do all known cap carbonates, but they lack a known underlying glacial deposit and do not necessarily rest on the transgressive surface. It is possible, but not likely, that the units represent post-glacial cap carbonates without a preserved/discovered underlying glaciogenic unit. More likely, processes independent of glaciation may cause negative ?13C excursions and cap carbonate-like facies and caution must be exercised when interpreting the meaning of seafloor precipitates in association with snowball Earth events.

Corsetti, Frank A.; Lorentz, Nathaniel J.; Pruss, Sara B.

315

Holocene activity of the Subequana Valley-Middle Aterno Valley normal fault system, south of the epicentral area of the April 6, 2009 "L'Aquila" earthquake (Mw 6.3): Implications for seismic hazard in central Italy  

NASA Astrophysics Data System (ADS)

Geological and paleoseismological analyses led along the 10 km long Subequana Valley fault, in central Apennines, located about 40 km S of the epicentre of the earthquake that struck central Italy in April 6, 2009 (Mw 6.3), indicate that this structure ruptured twice during the late Holocene, resulting in surface displacement with a slip per event of about 70-80 cm. The last activation occurred after the IV-II century b.C. and before the past millennium (perhaps during the II century b.C.), while the penultimate event occurred between 6381±30BP and 3511±37 PB. The presence of transtensive faults connecting the SVF with the 15 km long (at least) Middle Aterno Valley fault indicate that these structures belong to the same fault system, ?26 km long, that probably ruptures during M?6.7 earthquakes. Lastly, we analyse the possible influence of the Coulomb stress diffusion induced by the April 6 seismic event on the earthquake probability related to the analysed fault system.

Falcucci, Emanuela; Gori, Stefano; Moro, Marco; Galadini, Fabrizio; Pisani, Anna Rita; Fredi, Paola

2010-05-01

316

Three-dimensional hydrogeologic framework model for use with a steady-state numerical ground-water flow model of the Death Valley regional flow system, Nevada and California  

Microsoft Academic Search

The U.S. Geological Survey, in cooperation with the Department of Energy and other Federal, State, and local agencies, is evaluating the hydrogeologic characteristics of the Death Valley regional ground-water flow system. The ground-water flow system covers and area of about 100,000 square kilometers from latitude 35 degrees to 38 degrees 15 minutes North to longitude 115 degrees to 118 degrees

W. R. Belcher; C. C. Faunt; F. A. DAgnese

2002-01-01

317

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  

Microsoft Academic Search

Elevation data have been compiled into a digital data base for an â100,000-km² area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35°N, long 115°W, and lat 38°N, long 118°W. This region includes the Nevada Test Site, Yucca Mountain, and adjacent parts of southern Nevada and eastern California and encompasses

A. K. Turner; C. C. Faunt

1996-01-01

318

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

319

Late Cenozoic N-S shortening across the central Garlock fault in Pilot Knob Valley, California - Implications for structural and kinematic relations with the Panamint Valley fault system  

NASA Astrophysics Data System (ADS)

The intersection of the dextral (2-3 mm/yr) Panamint Valley fault system (PVFS) with the sinistral (5-15 mm/yr) Garlock fault (GF) in eastern Pilot Knob Valley (PKV) controls the active off-fault tectonic deformation in the southern Slate Range (SSR) and northern PKV. We suggest here that the 430+ m uplift of late Cenozoic sediments adjacent to the SSR partially accommodates decreased slip on the southern PVFS near the GF. We present preliminary data that constrain modern uplift in northern PKV: (1) Be-10 cosmogenic profiles, (2) OSL samples, (3) existing Earthscope 0.5 m airborne LiDAR and newly acquired terrestrial LiDAR, and (4) detailed soil PDI’s. Two uplifted terrace treads adjacent to the GF and one adjacent to the SSF are analyzed herein. A 50 ± 13 ka Be-10 cosmogenic profile age for a 16-m-high terrace tread adjacent to the GF suggests an uplift rate of ~0.32 ± 0.08 mm/yr. An additional Be-10 cosmogenic profile from a 12.5-m-high tread located 4.5 km west on the GF will test for spatial and temporal uplift rate variability. An OSL sample collected from this second cosmogenic profile will check the terrace’s age estimation. A second OSL sample collected from a 25.5-m-high terrace will allow for a slip-rate determination of a reverse fault near the SSR. We attribute the localized uplift between the SSR and the GF in northern PKV as strain accommodation between the southern PVFS and GF. If all reverse faults responsible for 430+ m of uplift are assumed to dip 70-80°, then approximately 155-76 m of horizontal N-S shortening is tenable. Likewise, the ca. 50 ka uplifted terrace adjacent to the GF would indicate a 0.12-0.06 mm/yr component of N-S shortening. Additional reverse faults to the north will add to this value, but lack of surfaces suitable for dating make a regional shortening estimate over this time interval challenging.

Rittase, W. M.; Walker, J. D.; Kirby, E.; McDonald, E.; Gosse, J.; Spencer, J. Q.; Mojave Red Iwbc

2010-12-01

320

Valley-Fill Standstones in the Kootenai Formation on the Crow Indian Reservation, South-Central Montana  

SciTech Connect

Subsurface data is being collected, organized, and a digital database is being prepared. An ACCESS database and PC-Arcview if being used to manage and interpret the data. Well data and base map have been successfully imported to Arcview and customized. All of the four 30 feet by 60 feet geologic surface geologic quadrangles have been scanned to produce a digital surface data base for the Crow Reservation. Field investigations inventoried for the presence of valley-fill deposits. These appear to represent at least a four major westward-trending valley systems.

David A. Lopez

1998-01-07

321

Using Gamma Spectrometry to Determine U, Th, and K Signatures in Cap Carbonates of the Death Valley Region and Their Relation to Other Carbonates  

NASA Astrophysics Data System (ADS)

We collected spectral gamma data (K, U, Th) and measured sections in cap carbonates (Noonday dolomite) and cap-like carbonates (Beck Spring dolomite) of the Death Valley region in order to explore elemental changes in the post-snowball oceans. The Snowball Earth theory of Hoffman et al. (1998) proposes dramatic post-glacial chemical weathering as large concentrations of carbon were removed from the atmosphere. This would result in a large input of terrigenous material; hence, we expect that carbonates formed under these conditions would demonstrate elevated K, U, Th levels in comparison to carbonates formed under more typical conditions. However, based on our preliminary findings, cap carbonates of the Noonday dolomite and cap-like carbonates of the Beck Spring dolomite have values (0-1% for K, 0.2-6.0 ppm for U, and 0.6-6.9 ppm for Th) that fall within the published range for those measured in carbonates (presumably non-cap or cap-like carbonates). Possible explanations for this include: (a) dilution of any terrigeneous signal by the vast amount of carbonate precipitating in the oceans, or (b) any biological activity that might have an influence on chemical processes in the ocean. A preliminary comparison of our spectral gamma data measured in the Noonday dolomite with published ? 13C data from the same section indicate similar trends in both proxies, namely, a very gradual decrease in values through the majority of the section (Lower Noonday) followed by a more noticeable increase in values in the upper part of the section (Upper Noonday). Further work will be necessary to determine the significance of this possible correlation. Additionally, planned analysis of hand specimens using a high-resolution gamma spectrometer should provide more details about the composition of cap-carbonates and provide further information about the conditions under which they were formed.

Hannon, M.; Lindberg, J.; Barrie, C.; Johnson, T.; Donatelle, A.; Goeden, J.; Holter, S.; Hickson, T.; Theissen, K.; Lamb, M.

2004-05-01

322

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

323

Potential of public lands in California's central valley as habitat for the endangered San Joaquin kit fox. [Vulpes macrotis mutica  

SciTech Connect

As part of an assessment of the impacts of their activities on the endangered San Joaquin kit fox and its essential habitat, the Department of Energy and Bureau of Land Management investigated the potential of public lands in the San Joaquin Valley as suitable habitat for the San Joaquin kit fox. (ACR)

O'Farrell, T.P.; McCue, P.; Sauls, M.L.; Kato, T.

1982-01-01

324

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

325

Ground-Water Budgets for the Wood River Valley Aquifer System, South-Central Idaho, 1995-2004.  

National Technical Information Service (NTIS)

This report describes the development of ground-water budgets for the Wood River Valley aquifer system for the 10-year period 1995-2004, as well as for a wet year (1995), and a dry year (2001) within that period. The report also includes discussions of th...

J. R. Bartolino

2009-01-01

326

Linking economic and integrated hydrologic models to investigate the effects of reduced surface water deliveries on the aquifers of California’s Central Valley  

NASA Astrophysics Data System (ADS)

Predicted global mean temperature increases will change the rates and timing of mountain-front discharges and thus the availability of surface water supplies for agricultural and urban water consumers. California’s water supply and distribution system collects runoff from the Sierra Nevada Mountain range in the northeastern and eastern part of the state, and routes this to agricultural and urban consumers in the central, western and southern parts of the state. The surface water collection and distribution system relies heavily on the storage of winter precipitation as snow in the Sierra Nevada Mountains, with moderately-sized reservoirs collecting and releasing melt-water through the spring and summer months. Higher elevations of the Sierra Nevada have already experienced a 0.60C rise and 10% reduction in snowpack, and continued warming may reduce snowpack volume by 25% by 2050, with further reductions likely as lower-elevation precipitation increasingly falls as rain. Snowpack reductions, environmental restrictions and recurring droughts may significantly constrain surface water supplies. Agricultural water users have historically increased groundwater pumping to replace surface water during droughts, and groundwater levels have recovered in subsequent years of higher precipitation (and recharge) and surface water flows. Central Valley aquifers could be significantly impacted if reduced snowpack leads to sustained increases in groundwater pumping. These impacts are being studied using the California Central Valley Groundwater-Surface Water Simulation Model (C2VSIM) and the Central Valley Production Model (CVPM). Multiple CVPM runs were conducted to simulate crop acreage changes in response to surface water reductions and groundwater depth increases, and were then converted to logit function parameters. C2VSIM was used to simulate three future levels of drought (corresponding to 30%, 50% and 70% reductions in precipitation) for periods of 10, 20, 30 and 60 years, each preceded by a 10-yr spin-up and a 30-yr recovery period. Simulations were conducted with fixed agricultural demands and incorporating dynamic changes in crop mix using the logit function parameters derived from CVPM. Simulation results with fixed agricultural demands suggest that an extended drought would have moderate impacts on aquifer heads in the northern Sacramento River Basin, locally severe impacts in the central San Joaquin River Basin, and regionally severe impacts in the southern Tulare Basin. Simulation results incorporating dynamic crop changes suggest acreage reductions and changes in crop mix may significantly reduce impacts on the aquifers.

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

2009-12-01

327

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

328

Pollen-derived history of timber exploitation from the Roman period onwards in the Romanche valley, central French Alps  

Microsoft Academic Search

The history of forestry in the Romanche river valley, south-east of Grenoble, France, is reconstructed for the past ca. 3000 years on the basis of detailed pollen analysis and AMS14C dating. Three deforestation phases are recorded during the last two millennia, each phase showing different features and also contrasting woodland succession in the post-clearance period. The first major deforestation is

Takeshi Nakagawa; Jacques-Louis de Beaulieu; Hiroyuki Kitagawa

2000-01-01

329

Boundary of the Eagle River Watershed Valley-Fill Aquifer, Eagle County, North-Central Colorado, 2006-2007  

USGS Publications Warehouse

This vector data set delineates the approximate boundary of the Eagle River watershed valley-fill aquifer (ERWVFA). This data set was developed by a cooperative project between the U.S. Geological Survey, Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority. This project was designed to evaluate potential land-development effects on groundwater and surface-water resources so that informed land-use and water management decisions can be made. The boundary of the ERWVFA was developed by combining information from two data sources. The first data source was a 1:250,000-scale geologic map of the Leadville quadrangle developed by Day and others (1999). The location of Quaternary sediments was used as a first approximation of the ERWVFA. The boundary of the ERWVFA was further refined by overlaying the geologic map with Digital Raster Graphic (DRG) scanned images of 1:24,000 topographic maps (U.S. Geological Survey, 2001). Where appropriate, the boundary of the ERWVFA was remapped to correspond with the edge of the valley-fill aquifer marked by an abrupt change in topography at the edge of the valley floor throughout the Eagle River watershed. The boundary of the ERWVFA more closely resembles a hydrogeomorphic region presented by Rupert (2003, p. 8) because it is based upon general geographic extents of geologic materials and not on an actual aquifer location as would be determined through a rigorous hydrogeologic investigation.

Rupert, Michael G.; Plummer, L. Niel

2009-01-01

330

Earthquake recurrence and fault behavior on the Homestead Valley fault -- Central segment of the 1992 Landers surface rupture sequence  

SciTech Connect

The 1992 M 7.5 Landers earthquake produced complex surface rupture on sections of the previously mapped Johnson Valley, Homestead Valley, and Emerson faults. The earthquake has raised questions about new faulting, characteristic earthquakes, and fault segmentation. To address these issues the authors initiated a study of both ruptured and unruptured fault segments, and report initial observations on the Homestead Valley fault (HVF). The authors site is located at the distal end of a large alluvial fan where 1992 right slip was 3 m, vertical slip was 40 cm, and the rupture followed pre-existing NE-facing scarps. Two trenches provide clear evidence of the two most recent pre-1992 surface faulting events. The trenches exposed alluvial fan and scarp derived colluvial deposits that are displaced and locally warped by both vertical strike-slip and low angle reverse-oblique( )-slip faults. At the main fault trace two pre-1992 colluvial wedges overlie a distinctive Bt soil horizon of late( ) Pleistocene age. Colluvium from the penultimate event has weak soil development, indicating a Holocene age for this faulting; apparent vertical displacement from this event is 35 cm, essentially the same as 1992. Preliminary observations indicate that recurrence of large magnitude earthquakes on faults of the Eastern California Shear Zone is one to two orders of magnitude longer than on major faults of the San Andreas system. The length of the HVF is short for this amount of offset, which suggests prior events may have also involved the rupture of multiple fault segments.

Cinti, F.R. (ING, Rome (Italy)); Fumal, T.E.; Garvin, C.D.; Hamilton, J.C.; Powers, T.J.; Schwartz, D.P. (Geological Survey, Menlo Park, CA (United States))

1993-04-01

331

H. R. 3113: an act providing for the coordinated operation of the Central Valley project and the State water project in California. Introduced in the Senate of the United States, Ninety-Ninth Congress, Second Session, March 25, 1985  

SciTech Connect

The House Committee on Energy and Natural Resources rewrote the Bill coordinating operations of the Central Valley Project in California and the state water project, and limited the Secretary of the Interior to no more than 75% of the Central Valley Project's annual yield. The Bill specifies procedures for water delivery contracts and reimbursements. Title II deals with the preservation of the Suisin Marsh District; Title III with the reclamation of small projects; and Title IV with contract validation. The document contains both the original and the amended wording of H.R. 3113.

Not Available

1986-01-01

332

Ground-Water Budgets for the Wood River Valley Aquifer System, South-Central Idaho, 1995-2004  

USGS Publications Warehouse

The Wood River Valley contains most of the population of Blaine County and the cities of Sun Valley, Ketchum, Haley, and Bellevue. This mountain valley is underlain by the alluvial Wood River Valley aquifer system which consists of a single unconfined aquifer that underlies the entire valley, an underlying confined aquifer that is present only in the southernmost valley, and the confining unit that separates them. The entire population of the area depends on ground water for domestic supply, either from domestic or municipal-supply wells, and rapid population growth since the 1970s has caused concern about the long-term sustainability of the ground-water resource. To help address these concerns this report describes a ground-water budget developed for the Wood River Valley aquifer system for three selected time periods: average conditions for the 10-year period 1995-2004, and the single years of 1995 and 2001. The 10-year period 1995-2004 represents a range of conditions in the recent past for which measured data exist. Water years 1995 and 2001 represent the wettest and driest years, respectively, within the 10-year period based on precipitation at the Ketchum Ranger Station. Recharge or inflow to the Wood River Valley aquifer system occurs through seven main sources (from largest to smallest): infiltration from tributary canyons, streamflow loss from the Big Wood River, areal recharge from precipitation and applied irrigation water, seepage from canals and recharge pits, leakage from municipal pipes, percolation from septic systems, and subsurface inflow beneath the Big Wood River in the northern end of the valley. Total estimated mean annual inflow or recharge to the aquifer system for 1995-2004 is 270,000 acre-ft/yr (370 ft3/s). Total recharge for the wet year 1995 and the dry year 2001 is estimated to be 270,000 acre-ft/yr (370 ft3/s) and 220,000 acre-ft/yr (300 ft3/s), respectively. Discharge or outflow from the Wood River Valley aquifer system occurs through five main sources (from largest to smallest): Silver Creek streamflow gain, ground-water pumpage, Big Wood River streamflow gain, direct evapotranspiration from riparian vegetation, and subsurface outflow (treated separately). Total estimated mean 1995-2004 annual outflow or discharge from the aquifer system is 250,000 acre-ft/yr (350 ft3/s). Estimated total discharge is 240,000 acre-ft/yr (330 ft3/s) for both the wet year 1995 and the dry year 2001. The budget residual is the difference between estimated ground-water inflow and outflow and encompasses subsurface outflow, ground-water storage change, and budget error. For 1995-2004, mean annual inflow exceeded outflow by 20,000 acre-ft/yr (28 ft3/s); for the wet year 1995, mean annual inflow exceeded outflow by 30,000 acre-ft/yr (41 ft3/s); for the dry year 2001, mean annual outflow exceeded inflow by 20,000 acre-ft/yr (28 ft3/s). These values represent 8, 13, and 8 percent, respectively, of total outflows for the same periods. It is difficult to differentiate the relative contributions of the three residual components, although the estimated fluctuations between the wet and dry year budgets likely are primarily caused by changes in ground-water storage. The individual components in the wet and dry year ground-water budgets responded in a consistent manner to changes in precipitation and temperature. Although the ground-water budgets for the three periods indicated that ground-water storage is replenished in wet years, statistical analyses by Skinner and others (2007) suggest that such replenishment is not complete and over the long term more water is removed from storage than is replaced. In other words, despite restoration of water to ground-water storage in wet years, changes have occurred in either recharge and (or) discharge to cause ground-water storage to decline over time. Such changes may include, but are not limited to: lining or abandoning canals and ditches, conversion of surface-water irriga

Bartolino, James R.

2009-01-01

333

Cytokines in the Central Nervous System: Regulatory Roles in Neuronal Function, Cell Death and Repair  

Microsoft Academic Search

Recent evidence suggests that neurons and glia can synthesize and secrete cytokines, which play critical roles in maintaining homeostasis in the central nervous system (CNS) by mediating the interaction between cells via autocrine or paracrine mechanisms. Circulating cytokines and soluble receptors also regulate neuronal function via endocrine mechanisms. Disturbance of the cytokine-mediated interaction between cells may lead to neuronal dysfunction

Yoshitatsu Sei; Ljubiša Vitkoviç; Mitsuo Yokoyama

1995-01-01

334

VALLEY-FILL SANDSTONE IN THE KOOTENAI FORMATION ON THE CROW INDIAN RESERVATION, SOUTH-CENTRAL MONTANA  

SciTech Connect

The subsurface database has been completed for the project. An ACCESS database converted to PC-Arcview is being used to manage and interpret the data. Well data and base map data have been successfully imported into Arcview and customized to meet the needs of this project. Log tops and other data from all of the exploration wells in the area have been incorporated into the data base, except for some wells that have no available logs or other information. All of the four 30 x 60 feet geologic quadrangles have been scanned to produce a digital surface geologic data base for the Crow Reservation and all are nearing completion. Formal technical review prior to publication has been completed for all the quandrangles; Billings, Bridger; Hardin, and Lodge Grass. All four quadrangles are in the Bureau's Publications Department being prepared for submittal to a printer. Field investigations were completed during the third quarter, 1997. With the help of a student field assistant from the Crow Tribe, the entire project area was inventoried for the presence of valley-fill deposits in the Kootenai Formation. Field inventory has resulted in the identification of nine exposures of thick valley-fill deposits. These appear to represent at least four major westward-trending valley systems. All the channel localities have been measured and described in detail and paleocurrent data has been collected from all but one locality. In addition, two stratigraphic sections were measured in areas where channels are absent. One channel has been traced over a distance of about 60 miles and exhibits definite paleostructural control. An abstract describing this channel was submitted and the paper was presented at the Williston Basin Symposium in October, 1998. A follow on proposal to conduct a soil gas geochemical survey of the reservation was approved and the contract was received in late August. The sampling will be conducted next summer and will involve Crow students.

David A. Lopez

1999-04-12

335

Valley-Fill Sandstones in the Kootenai Formation on the Crow Indian Reservation, South-Central Montana  

SciTech Connect

Subsurface data continues to be collected, organized, and a digital database is being prepared for the project. An ACCESS database and PC-Arcview is being used to manage and interpret the data. Well data and base map data have been successfully imported into Arcview and customized to meet the needs of this project. Log tops and other data from about ¾ of the exploration wells in the area have been incorporated into the data base. All of the four 30? X 60? geologic quadrangles have been scanned to produce a digital surface geologic data base for the Crow Reservation and all are nearing completion. Formal technical review prior to publication has been completed for all the quadrangles; Billings, Bridger; Hardin, and Lodge Grass. Final GIS edits are being made before being forwarded to the Bureau?s Publications Department. Field investigations were completed during the third quarter, 1997. With the help of a student field assistant from the Crow Tribe, the entire project area was inventoried for the presence of valley-fill deposits in the Kootenai Formation. Field inventory has resulted in the identification of nine exposures of thick valley-fill deposits. These appear to represent at least four major westward-trending valley systems. All the channel localities have been measured and described in detail and paleocurrent data has been collected from all but one locality. In addition, two stratigraphic sections were measured in areas where channels are absent. One channel has bee traced over a distance of about 60 miles and exhibits definite paleostructural control. An abstract describing this channel has been submitted and accepted for presentation at the Williston Basin Symposium in October, 1998.

David A. Lopez

1998-07-03

336

Extensional geometries in the northern Grant Range, east-central Nevada - Implications for oil occurrences in Railroad Valley  

SciTech Connect

Tertiary heterogeneous extension in the northern Grant Range, Nevada, is manifested by a stacked array of curviplanar low-angle attenuation faults that formed concurrent with arching. Attenuation was controlled by lithologic character, structural depth, and geometry of the arch. Extension appears to be greater on the west side of the range than on the east. On the east side of the range, the stacked array of low-angle attenuation faults is subparallel to bedding and attenuation is distributed across many stacked fault zones; except at highest crustal levels, these faults are blind. On the west side of the range, the low-angle attenuation faults of the stacked array merge into a single, major down-to-the-west fault zone across which as much as 19,000 ft of strata are omitted. Arching of the fault array resulted in an extensional culmination. Cross sections incorporating seismic and drill-hole data suggest that the low-angle attenuation faults (particularly the major down-to-the-west attenuation fault) seen in the range extend into Railroad Valley on the west side of the range with no significant offset by high-angle normal faults. Thus, the topographic expression of Grant Range and Railroad Valley may be due to the synchronous arching and low-angle faulting. These data indicate that both petroleum source and reservoir rocks in Railroad Valley oil fields are located in relatively immature but extensively fractured rocks of the upper plate to the extensional ramp. Lower plate rocks are metamorphosed, illustrate ductile behavior, and lack significant porosity and permeability.

Lund, K.; Perry, W.J. Jr. (Geological Survey, Denver, CO (United States)); Beard, L.S. (Geological Survey, Flagstaff, AZ (United States))

1991-06-01

337

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

338

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

SciTech Connect

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 to 3 wt.-%, with modes at about 0.5 to 0.7, 1.5, and 2 to 3 wt-% TOC. However, in the Standard Amoco Carson Sink 1 well, some of these samples have up to 3 wt-% less TOC than reported by Hastings (1979) and these are thought to represent drill cutting samples that have been depleted in more TOC rich rock chips. Even if the TOC data are biased, these TOC-depleted samples are still oil-prone rocks, with hydrogen indices commonly above 400 mg hydrocarbon/g C, and some samples with TOC in the 2-3 wt.-% range. Analysis of an oil show at Kyle Hot Springs in Buena Vista Valley revealed a wax-rich, low sulfur oil probably from a carbonate-rich, hypersaline lacustrine source rock. This oil could be generated from strata similar to those analyzed above. Other Tertiary source rocks in the two valleys consist of lenses of humic coals that appear to be gas prone. Shows of biogenic(?) gas from shallow wells in Tertiary to Holocene lacustrine strata are common in the Carson Sink. Mesozoic rocks locally may have remaining hydrocarbon generation potential in the Stillwater Range which lie along the eastern margin of the Carson Sink. Published conodont alteration index data shows that the Paleozoic rocks are overmature. Reconstructed thermal histories of the Carson Sink and Buena Vista Valley areas, indicate petroleum is presently being generated. Mechanisms for petroleum generation are rapid burial (140 m/m.y.) in a high geothermal gradient (45 to 110{degrees}C/km), and hydrothermal and contact metamorphism.

Barker, C.E. [Geological Survey, Denver, CO (United States)

1995-06-01

339

Neurotrophin3 prevents the death of adult central noradrenergic neurons in vivo  

Microsoft Academic Search

NEUROTROPHIN-3 (NT-3)1-4 and neurotrophin-4\\/5 (NT-4)5-7, together with nerve growth factor and brain-derived neurotrophic factor, are members of the neurotrophin family of proteins8,9, which supports the survival of vertebrate neurons. However, no function in vivo has been described for NT-4 and limited information is available on the role of the other neurotrophins in the central nervous system in vivo. Nerve growth

Ernest Arenas; Hakan Persson

1994-01-01

340

Record of Decision on Final Environmental Impact Statement for Fish Passage Improvement Project at the Red Bluff Diversion Dam, Central Valley Project, California Mid-Pacific Region. Managing Water in the West.  

National Technical Information Service (NTIS)

The Red Bluff Diversion Dam (RBDD) is part ofthe Central Valley Project's Sacramento Canals Unit, authorized in 1950. In addition to the RBDD, unit facilities include Funks Dam, the Coming pumping plant, the Tehama-Colusa (TC) Canal, and the Coming Canal....

2008-01-01

341

Interagency Task Force for the Economic Development of the Central San Joaquin Valley. 2003-2004 Progress Report and Action Plan.  

National Technical Information Service (NTIS)

The San Joaquin Valley (the Valley) is a region with unique and serious social, economic, and environmental challenges that merit special attention by the federal government. In February 2002, President Bush implemented Executive Order 13173, which create...

2004-01-01

342

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

343

POST CLOSURE INSPECTION AND MONITORING REPORT FOR CORRECTIVE ACTION UNIT 417: CENTRAL NEVADA TEST AREA - SURFACE, HOT CREEK VALLEY, NEVADA, FOR CALENDAR YEAR 2004  

SciTech Connect

This post-closure inspection and monitoring report has been prepared according to the stipulations laid out in the Closure Report (CR) for Corrective Action Unit (CAU) 417, Central Nevada Test Area (CNTA)--Surface (U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office [NNSA/NV], 2001), and the Federal Facility Agreement and Consent Order (FFACO, 1996). This report provides an analysis and summary of site inspections, subsidence surveys, meteorological information, and soil moisture monitoring data for CAU 417, which is located in Hot Creek Valley, Nye County, Nevada. This report covers Calendar Year 2004. Inspections at CAU 417 are conducted quarterly to document the physical condition of the UC-1, UC-3, and UC-4 soil covers, monuments, signs, fencing, and use restricted areas. The physical condition of fencing, monuments, and signs is noted, and any unusual conditions that could impact the integrity of the covers are reported. The objective of the soil moisture monitoring program is to monitor the stability of soil moisture conditions within the upper 1.2 meters (m) (4 feet [ft]) of the UC-1 Central Mud Pit (CMP) cover and detect changes that may be indicative of moisture movement exceeding the cover design performance expectations.

BECHTEL NEVADA; NNSA NEVADA SITE OFFICE

2005-04-01

344

Measurement of evapotranspiration in phreatophyte areas, Smith Creek Valley and Carson Desert, west-central Nevada, 1983  

USGS Publications Warehouse

Evaporation from bare soils and evapotranspiration from phreatophyte areas are major sources of natural groundwater loss in the Great Basin region of Nevada, Utah, and adjacent states. This study evaluated three methods for determining evapotrans- piration under natural conditions and provides quantitative estimates of evapotranspiration. Two of the methods used, the eddy-correlation and the Bowen ratio methods, measure actual evapotrans- piration under natural conditions, whereas the Penman method measures potential evapotranspiration. Phreatophytes at the Smith Creek Valley site (near Austin, Nev.) consist mainly of rabbitbrush. Actual evapotranspiration for 1983 at this site, estimated by the eddy-correlation method, was about 0.32 m/yr, compared with a calculated potential evapotrans- piration (measured by the Penman method) of about 2.0 m/yr. Phreatophytes at the Carson Desert site (near Fallon, Nev.) consist predominantly of greasewood. Estimated actual evapotranspiration at this site for 1983 (eddy-correlation method) was 0.18 m/yr, compared with a calculated potential evapotranspiration (Penman method) of 1.8 m/yr.

Carman, R. L.

1993-01-01

345

Critical controlling of PRED system of oasis ecology in the arid region of central Asia: a case study of Keriya River Valley oases, Xinjiang  

NASA Astrophysics Data System (ADS)

Oases is a special ecosystem formed in arid climate and hungriness environment, in which resident, water and soil are the principal factor and exchanges of materials, energy and information are the main functional characteristics. The oases regions in central Asia are not only the basilic cradle of civilization of human beings, but also the important strategic places in world growing awareness of the potential benefits. We choose Keriya River Basin oases in south of Xinjiang as a case to study critical controlling of Oases Evolution, Based on the theories and methods used for environmental geology, physical geography, land resource research, and oases ecology. This study try to indicate the essential factors driving the oases ecosystem and the interactional dynamic mechanism in different scales and levels, confirm the optimal equilibrium aggregate of harmonious development between Population, Resources, Environment and Development, and establish the critical controlling pattern of sustainable development. We advance the indicator system to research the evolution of the PRED System of oases in Keriya River valley oases, in basis of the information derived from the field investigation and local materials. According to inquisitional result based on technical support of Geographic Information System (GIS) and Remote Sense (RS), the comparisons and analyses are carried out in land use at the upper reaches, vegetation change in the middle reaches, and desertification at the lower reaches, which narrates the regulations of Keriya River Valley oases land cover dynamic change. The main land cover types represent distinct characteristics of the local place. On the basis of field survey and statistical data, we use ARCINFO software to preprocess these data and the 2 TM satellite images. Through analyzing these images resulting from post-classification compare, we sums up the concrete quantificational dynamic distributed data of 13 land types covering a span of 15 years and regulation of the local ecological environment system. It finally points out that the trend of Keriya River Valley oases desertification expansion is mainly related to two important reasons: impact of natural environment and impact of human activities. In order to improve the local ecological environment, people inhabited this

Chen, Rui; Liu, Jiaqi; Niu, Wenyuan; Deng, Xiangzheng; Mu, Guijin; Wagner, Mayke; Geldmacher, Karl

2003-07-01

346

Stable isotopes as indicators of sources and processes influencing nitrate distributions in dairy monitoring wells and domestic supply wells in the Central Valley, California  

NASA Astrophysics Data System (ADS)

Nitrate concentrations above the 10 mg/L NO3-N maximum contaminant level (MCL) have been found in many wells throughout the Central Valley, California. This area contains many possible anthropogenic nitrate sources including current and historic agriculture, private septic systems, municipal waste water, and confined animal feeding operations (primarily dairies). In order to better understand the potential contributions of dairy manure derived nitrate to both shallow and deep groundwater, we used a combined chemical, stable isotope, and age-dating approach for water samples collected from a network of shallow groundwater monitoring wells located on seven different dairies, and from a survey of approximately 200 deeper domestic supply wells (used for drinking water and dairy operations). Groundwater from shallow monitoring wells and deep supply wells was collected in two geographic regions. In the northern region, the lower San Joaquin Valley, the water table is shallow (2- 5 m below surface) and therefore considered highly vulnerable to contamination, while in the southern region, the Tulare Lake Basin, the water table is much deeper (20 - 30 m). Mean ?15N of nitrate in dairy monitoring wells in both the north and south regions was significantly higher than the mean ?15N measured in the deeper supply wells, and also showed greater variability. Mean ?15N and ?18O values measured in the deep supply wells were not significantly different between the north and south regions. Mean nitrate concentrations, ?15N, and ?18O were significantly higher in the northern (lower San Joaquin Valley) monitoring wells in comparison to the southern (Tulare Lake Basin) monitoring wells. Nitrate isotope measurements indicated that many of the northern monitoring wells had consistently high contributions of manure-derived nitrate to the shallow groundwater during the 16 month study. Monitoring wells located in relatively new dairies in the south region showed little evidence of manure-derived nitrate, while those located in much older dairies in the south region showed a very wide range of nitrate isotope values, indicating significant nitrate contributions from multiple sources including manure and industrial fertilizer and biological processing effects. Combined nitrate concentration and isotopic data from all the monitoring wells showed very little evidence of significant saturated-zone denitrification. Monitoring well networks within individual dairies showed wide ranges of nitrate concentrations, nitrate isotopic compositions, and geochemical compositions, confirming the heterogeneity of the nitrate loading across dairy facilities and indicating that measurements from any single monitoring well may not be representative of general groundwater quality downgradient of an individual dairy.

Young, M. B.; Harter, T.; Kendall, C.; Silva, S. R.; Esser, B. K.; Singleton, M. J.; Holstege, D.; Lockhart, K.; Applegate, O.

2011-12-01

347

Groundwater Quality, Age, and Probability of Contamination, Eagle River Watershed Valley-Fill Aquifer, North-Central Colorado, 2006-2007  

USGS Publications Warehouse

The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado. Ground- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.

Rupert, Michael G.; Plummer, L. Niel

2009-01-01

348

Evidence for late-paleozoic brine migration in Cambrian carbonate rocks of the central and southern Appalachians: implications for Mississippi Valley-type sulfide mineralization  

SciTech Connect

Many Lower Paleozoic limestones and dolostones in the Valley and Ridge province of the central and southern Appalachians contain 10 to 25 weight percent authigenic potassium feldspar. This was considered to be a product of early diagenesis, however, /sup 40/Ar//sup 39/Ar analyses of overgrowths on detrital K-feldspar in Cambrian carbonate rocks from Pennsylvania, Maryland, Virginia, and Tennessee yield Late Carboniferous-Early Permian ages (278-322 Ma). Simple mass balance calculations suggest the feldspar could not have formed isochemically, but required the flux of multiple pore volumes of fluid through the rocks, reflecting regional fluid migration events during the Late-Paleozoic Alleghanian orogeny. Microthermometric measurements of fluid inclusions in overgrowths on detrital K-feldspar and quartz grains from unmineralized rocks throughout the study area indicate homogenization temperatures from 100/sup 0/ to 200/sup 0/C and freezing point depressions of -14/sup 0/ to -18.5/sup 0/C. The apparent similarity of these fluids to fluid inclusions in ore and gangue minerals of nearby Mississippi Valley-type (MVT) deposits suggests that the regional occurrences of authigenic K-feldspar and MVT mineralization may be genetically related. This hypothesis is supported by the discovery of authigenic K-feldspar intergrown with sphalerite in several mines of the Mascot-Jefferson City District, E. Tennessee. Regional potassic alteration in unmineralized carbonate rocks and localized occurrences of MVT mineralization are both explainable by a gravity-driven flow model, in which deep brines migrate towards the basin margin under a hydraulic gradient established during the Alleghanian orogeny.

Hearn, P.P. Jr; Sutter, J.F.; Belkin, H.E.

1987-05-01

349

Oil exploration in Pine Valley, Nevada  

Microsoft Academic Search

Three oil fields have already been established in Pine Valley, which is located in north-central Nevada along the late Mesozoic thrust trend. The potential exists for much more future exploration because of excellent reservoir potential, favorable hydrocarbon generating system, and trapping mechanisms. The Devonian is one of the main target reservoirs of Pine Valley. Pine Valley lies near the Devonian

C. H. Scott; A. K. Chamberlain

1989-01-01

350

Estuarine fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution  

Microsoft Academic Search

We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial

Tim van der Schriek; David G. Passmore; Jose Rolão; Anthony C. Stevenson

2007-01-01

351

Estuarine–fluvial floodplain formation in the Holocene Lower Tagus valley (Central Portugal) and implications for Quaternary fluvial system evolution  

Microsoft Academic Search

We present a brief synthesis of the Quaternary fluvial record in the Lower Tagus Basin (central Portugal), concentrating on factors controlling infill and incision. The Holocene part of the record forms the focus of this paper and guides the questioning of the basic assumptions of the established Quaternary fluvial evolution model, in particular the link between sea-level change and fluvial

Tim van der Schriek; David G. Passmore; Jose Rolão; Anthony C. Stevenson

2007-01-01

352

Primary and secondary porosity development in valley fill, marine sandstone reservoirs - Misener Formation, north-central Oklahoma  

Microsoft Academic Search

The Devonian Misener formation in north-central Oklahoma consists of a series of discontinuous sand and shale bodies deposited in erosional topographic lows on the post-Hunton unconformity surface. Paleontological, mineralogical, and sedimentological evidence supports a marine depositional setting. Rapid changes in sandstone thickness and reservoir properties are characteristic of Misener sands. These sands were episodically deposited, fine upward, and commonly interfinger

D. R. Prezbindowski; B. M. Francis; R. D. Fritz

1989-01-01

353

A model of central place forager prey choice and an application to faunal remains from the Mimbres Valley, New Mexico  

Microsoft Academic Search

Drawing on models from foraging theory, many researchers have used assemblages of animal bones from archaeological sites to document cases of resource depression and reduced foraging efficiency. This paper presents a model of central place forager prey choice that unifies several issues that these previous studies have addressed through the use of separate models. In comparison to the models usually

Michael D Cannon

2003-01-01

354

Creeping Deformation by the Precise Leveling Survey at the central part of the Longitudinal valley fault, Southeast Taiwan  

NASA Astrophysics Data System (ADS)

We would like to know the distributed asperity for seismic hazard and forecast. It is closely related to slip distribution on the fault in interseismic. We focused on the accumulating process of the stress at the boundary between the creeping and the locking zone, to clear the behavior on the fault. The Longitudinal Valley Fault (LVF), 150 km long and NNE-SSW striking, passes through the eastern Taiwan, and represents the obvious surface expression of the collision boundary between the Philippine Sea plate and the Eurasian continental plate. Owing to such a high deformation rate, many earthquakes have occurred along the LVF. The 1951 earthquake sequence represents a good example. The southern of LVF segment is observed to be high speed creeping based on the creep meter and leveling survey etc. The northern of LVF segment is not observed to be creeping and are found huge earthquakes evidence by paleo-seismology study in the trench. Yuili fault is one of the active segments of the longitudinal valley faults, is located around the boundary between creeping and locking area. It is reverse fault with east dip. We established about 30km leveling route from Yuli to Changbin to detect the vertical deformation in detail. Murase et al. (2009, 2010, and 2011) established about 30 km densely leveling route from Yuli to Changbin to detect the vertical deformation across the LVF for two years. As a result, the vertical displacement is 1.7 cm in 200 m across the LVF and 2.7 cm in 1000 m, referred to the west end of our route. In addition, a synclinal deformation is detected on the hanging wall side of the fault. This result is caused by the geometry of and the slipping distribution on the fault. The deformation detected in the period from 2009 to 2010 denotes the same tendency and rate of that from 2008 to 2009. We compared to the airphotographs which are taken by Taiwanese government at different age (1978 and 2007). If the creeping on the fault has continued for 30 years, the accumulation of displacement reaches about 1m, which is significantly-distinguishable by photogrammetric method. We measure profiles across the fault on 1978 and 2007 air-photograph by photogrammetric system respectively. The comparing result is shown that there are regional differences in deformation in relatively narrow region. About this result, we think two possibility; one is the creeping is not uniformity along the fault, second is the photogrammetry is not enough quality. We should actually check the creeping or not. We made thee new leveling survey lines in last year. In this August , we carried out second leveling survey in three area. We can show the variation of the deformation pattern and uplift rate across the LVF in this presentation.

Matta, N.; Murase, M.; Ishiguro, S.; Ozawa, K.; Lin, J.; Chen, W.; Lin, C.

2011-12-01

355

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

356

Taxonomic diversity of insects from the relic steppes of the Mid-Lena River Valley (Central Yakutia)  

Microsoft Academic Search

Data on insects of the central Yakutian steppes preserved in the relic state since the Late Pleistocene are presented. Orthoptera,\\u000a Homoptera, Heteroptera, Coleoptera, and Diptera are used as examples to demonstrate that, in addition to meadow and meadow-steppe\\u000a species, these steppes are inhabited by species belonging to an extrazonal steppe fauna-genetic complex comprising five elements:\\u000a Eurasian, Dauria-Mongolian, Black Sea-Kazakhstan, desert-steppe,

A. K. Bagachanova; N. N. Vinokurov; T. G. Evdokarova; Yu. V. Ermakova; S. N. Nogovitsyna; A. A. Popov

2011-01-01

357

Water-Resource Trends and Comparisons Between Partial-Development and October 2006 Hydrologic Conditions, Wood River Valley, South-Central Idaho  

USGS Publications Warehouse

This report analyzes trends in ground-water and surface-water data, documents 2006 hydrologic conditions, and compares 2006 and historic ground-water data of the Wood River Valley of south-central Idaho. The Wood River Valley extends from Galena Summit southward to the Timmerman Hills. It is comprised of a single unconfined aquifer and an underlying confined aquifer present south of Baseline Road in the southern part of the study area. Streams are well-connected to the shallow unconfined aquifer. Because the entire population of the area depends on ground water for domestic supply, either from domestic or municipal-supply wells, rapid population growth since the 1970s has raised concerns about the continued availability of ground and surface water to support existing uses and streamflow. To help address these concerns, this report evaluates ground- and surface-water conditions in the area before and during the population growth that started in the 1970s. Mean annual water levels in three wells (two completed in the unconfined aquifer and one in the confined aquifer) with more than 50 years of semi-annual measurements showed statistically significant declining trends. Mean annual and monthly streamflow trends were analyzed for three gaging stations in the Wood River Valley. The Big Wood River at Hailey gaging station (13139500) showed a statistically significant trend of a 25-percent increase in mean monthly base flow for March over the 90-year period of record, possibly because of earlier snowpack runoff. Both the 7-day and 30-day low-flow analyses for the Big Wood River near Bellevue gaging station (13141000) show a mean decrease of approximately 15 cubic feet per second since the 1940s, and mean monthly discharge showed statistically significant decreasing trends for December, January, and February. The Silver Creek at Sportsman Access near Picabo gaging station (13150430) also showed statistically significant decreasing trends in annual and mean monthly discharge for July through February and April from 1975 to 2005. Comparisons of partial-development (ground-water conditions from 1952 to 1986) and 2006 ground-water resources in the Wood River Valley using a geographic information system indicate that most ground-water levels for the unconfined aquifer in the study area are either stable or declining. Declines are predominant in the southern part of the study area south of Hailey, and some areas exceed what is expected of natural fluctuations in ground-water levels. Some ground-water levels rose in the northern part of the study area; however, these increases are approximated due to a lack of water-level data in the area. Ground-water level declines in the confined aquifer exceed the range of expected natural fluctuations in large areas of the confined aquifer in the southern part of the study area in the Bellevue fan. However, the results in this area are approximated due to limited available water-level data.

Skinner, Kenneth D.; Bartolino, James R.; Tranmer, Andrew W.

2007-01-01

358

Trends in nitrate concentrations and determination of its origin using stable isotopes (18O and 15N) in groundwater of the Western Central Valley, Costa Rica.  

PubMed

A study was conducted to evaluate long-term trends in nitrate concentrations and to try to identify the origin of nitrate using stable isotopes (15N(NO3-) and 18O(NO3-)) in the aquifers of the western Central Valley, Costa Rica, where more than 1 million people depend on groundwater to satisfy their daily needs. Data from 20 sites periodically sampled for 4 to 17 years indicate an increasing trend in nitrate concentrations at five sites, which in a period ranging from 10 to 40 years, will exceed recommended maximum concentrations. Results of isotopic analysis indicate a correspondence between land use patterns and the isotopic signature of nitrate in groundwater and suggest that urbanization processes without adequate waste disposal systems, followed by coffee fertilization practices, are threatening water quality in the region. We conclude that groundwater management in this area is not sustainable, and that land use substitution processes from agricultural activity to residential occupation that do not have proper sewage disposal systems may cause a significant increment in the nitrate contaminant load. PMID:16989507

Reynolds-Vargas, Jenny; Fraile-Merino, Julio; Hirata, Ricardo

2006-08-01

359

Measurements of hydrocarbons and halogenated hydrocarbons over the Southern California Air Basin and the California Central Valley during the CalNex-2010 mission  

NASA Astrophysics Data System (ADS)

The CalNex 2010 mission was an intensive study of air quality and climate related processes over California. The study was designed to examine emissions, chemical transformations, climate processes, transport, and meteorology in California. Objectives included improving emission inventories of greenhouse gases, traditional air pollutants and ozone and aerosol precursors. The NOAA P-3 aircraft was one of the platforms used during the study, which took place during May and June, 2010. Flights covered the Southern California Air Basin, the California Central Valley, and the nearshore ocean atmosphere. This presentation will focus on the measurements from a whole air sampler, which was part of the P3 instrument payload. The sampler collected approximately 72 samples per flight. Gases measured from these samples include a wide range of natural and anthropogenic hydrocarbons, halogenated hydrocarbons, organic nitrates, and selected sulfur species. We will discuss the distributions and relationships that were observed in the study region for these gases and examine implications for emissions and transport and chemical processing.

Atlas, E. L.; Lueb, R.; Blake, D. R.; Meinardi, S.; Ryerson, T. B.; Holloway, J. S.; Peischl, J.; de Gouw, J. A.; Warneke, C.; Pollack, I. B.; Trainer, M.; Hendershot, R.

2010-12-01

360

Farmers' perceptions of land degradation and their investments in land management: a case study in the Central Rift Valley of Ethiopia.  

PubMed

To combat land degradation in the Central Rift Valley (CRV) of Ethiopia, farmers are of crucial importance. If farmers perceive land degradation as a problem, the chance that they invest in land management measures will be enhanced. This study presents farmers' perceptions of land degradation and their investments in land management, and to what extent the latter are influenced by these perceptions. Water erosion and fertility depletion are taken as main indicators of land degradation, and the results show that farmers perceive an increase in both indicators over the last decade. They are aware of it and consider it as a problem. Nevertheless, farmers' investments to control water erosion and soil fertility depletion are very limited in the CRV. Results also show that farmers' awareness of both water erosion and soil fertility decline as a problem is not significantly associated with their investments in land management. Hence, even farmers who perceive land degradation on their fields and are concerned about its increase over the last decade do not significantly invest more in water erosion and soil fertility control measures than farmers who do not perceive these phenomena. Further research is needed to assess which other factors might influence farmers' investments in land management, especially factors related to socioeconomic characteristics of farm households and plot characteristics which were not addressed by this study. PMID:23511911

Adimassu, Zenebe; Kessler, Aad; Yirga, Chilot; Stroosnijder, Leo

2013-03-20

361

Aerial photographic interpretation of lineaments and faults in late cenozoic deposits in the Eastern part of the Benton Range 1:100,000 quadrangle and the Goldfield, Last Chance Range, Beatty, and Death Valley Junction 1:100,000 quadrangles, Nevada and California  

Microsoft Academic Search

Lineaments and faults in Quaternary and late Tertiary deposits in the southern part of the Walker Lane are potentially active and form patterns that are anomalous with respect to the typical fault patterns in most of the Great Basin. Little work has been done to identify and characterize these faults, with the exception of those in the Death Valley-Furnace Creek

M. C. Reheis; J. S. Noller

1991-01-01

362

Molecular and Geochemical Evidence of in situ Denitrification at a Dairy Field Site in the Central Valley of California  

NASA Astrophysics Data System (ADS)

Rising nitrate concentrations in California groundwater threaten an already strained water supply. Under certain conditions, however, intrinsic microbial denitrification can mitigate this problem. We present results from a field study at a central California dairy that document saturated-zone denitrification using a combination of molecular and geochemical methods. Geochemical measurements to assess denitrification included nitrate concentration, dissolved oxygen (DO) concentration, dissolved excess N2, and stable isotope composition of nitrate. Sharp decreases in nitrate concentrations with depth corresponded to sharp decreases in DO concentrations and decreasing redox potential. Nitrate in groundwater from this study had ?15N values (5 to 60 ‰) and ?18O values (-4 to 25 ‰) that plotted with a ?18O/?15N slope of 0.5, consistent with denitrification. Dissolved N2 was found at concentrations well above Ar-normalized concentrations predicted for atmospheric N2, consistent with reduction of nitrate to N2. in situ denitrification was further documented by increased populations of denitrifying bacteria in zones with geochemical signatures of denitrification. Real-time, quantitative, Polymerase Chain Reaction (qPCR) analysis was used to determine denitrifying bacterial cell populations present in aquifer sediment samples by measuring the abundance of genes encoding nitrite reductase, a central enzyme involved in denitrification. Real-time qPCR primers and probes allowing for universal detection of both the nirS (Fe-containing nitrite reductase) and nirK (Cu-containing nitrite reductase) genes in environmental samples were designed based on multiple alignments of over 30 nirS and nirK gene sequences available in GenBank. Trends in total eubacterial populations were also monitored by real-time qPCR analysis. Although geochemical measurements alone can sometimes convincingly indicate denitrification, the real-time qPCR analysis used in this study provides additional valuable information, namely: populations of denitrifying bacteria in an area (which is useful for reactive-transport modeling) and localization of activity to a specific well (in contrast to geochemical indicators, which may record upgradient denitrification).

Esser, B. K.; Letain, T. E.; Singleton, M. J.; Beller, H. R.; Kane, S. R.; Balser, L. M.; Moran, J. E.

2005-12-01

363

Primary and secondary porosity development in valley fill, marine sandstone reservoirs - Misener Formation, north-central Oklahoma  

SciTech Connect

The Devonian Misener formation in north-central Oklahoma consists of a series of discontinuous sand and shale bodies deposited in erosional topographic lows on the post-Hunton unconformity surface. Paleontological, mineralogical, and sedimentological evidence supports a marine depositional setting. Rapid changes in sandstone thickness and reservoir properties are characteristic of Misener sands. These sands were episodically deposited, fine upward, and commonly interfinger with an equivalent shale facies. The basal contact of the Misener sandstone bodies is erosional with the inclusion of shale, phosphate, and sandstone clasts in a medium-grained, dolomitic quartzarenite sandstone. Reservoir porosity is best developed in the poorer sorted, medium-grained, dolomitic quartzarenites of the channel facies. A mixed mineralogy sandstone is critical to the preservation of primary porosity and the development of secondary porosity. Well-sorted, fine-grained quartzarenite sandstones (nonchannel) have been extensively quartz cemented. Early dolomitization in the mixed mineralogy sandstones prevented quartz cementation and preserved primary porosity. Sandstones containing preserved primary porosity served as pathways for the movement of subsurface fluids. These fluids generated secondary porosity by the selective dissolution of glauconite, phosphate, and lithic grains. Significant post-hydrocarbon diagenesis in the form of bitumen precipitation, dedolomitization, and calcite cementation has occurred in the water zone of several Misener sandstone reservoirs. The occurrence of these diagenetic products in the oil column suggests post entrapment tilting of some reservoirs.

Prezbindowski, D.R.; Francis, B.M.; Fritz, R.D. (International Petrology Research, Tulsa, OK (USA))

1989-08-01

364

Macroinvertebrate Communities in Restored and Natural Slough Wetlands: Evaluation of Restoration Practices in the Central Platte River Valley.  

NASA Astrophysics Data System (ADS)

Wetlands in the central Platte River basin of Nebraska provide numerous ecosystem services, but these systems have been degraded through drainage for agriculture and increasing river regulation. Restoration is currently a common means of increasing wetland area in this region, but little is known about the success of these restorations. We quantified macroinvertebrate abundance, biomass, and community structure in restored wetlands ranging in age from 5-11yrs old and compared them with proximal natural systems to assess success. Analyses of seasonal samples showed that total macroinvertebrate abundance, biomass, richness, and diversity were similar between restored and natural wetlands. However, biomass values reflected some differences in community and functional structure. Whereas insects constituted most biomass in natural systems (55%), mollusks, mostly Physella and Fossaria, dominated biomass (61%) in restorations. In natural wetlands, collector-gatherers and predators contributed most to mean biomass (~29% each), followed by a relatively even distribution of herbivores, collector-filterers, and scrapers. In contrast, collector-gatherers contributed most to mean biomass in restored wetlands (47%), followed by scrapers (43%) and predators (13%). Although total values and most abundance-based metrics suggested that macroinvertebrate communities had recovered in restored wetlands, biomass patterns indicate that recovery of communities and function is not complete.

Meyer, C. K.; Whiles, M. R.

2005-05-01

365

State-dependent life history models in a changing (and regulated) environment: steelhead in the California Central Valley  

PubMed Central

We use a state dependent life history model to predict the life history strategies of female steelhead trout (Oncorhynchus mykiss) in altered environments. As a case study of a broadly applicable approach, we applied this model to the American and Mokelumne Rivers in central California, where steelhead are listed as threatened. Both rivers have been drastically altered, with highly regulated flows and translocations that may have diluted local adaptation. Nevertheless, evolutionary optimization models could successfully predict the life history displayed by fish on the American River (all anadromous, with young smolts) and on the Mokelumne River (a mix of anadromy and residency). The similar fitness of the two strategies for the Mokelumne suggested that a mixed strategy could be favored in a variable environment. We advance the management utility of this framework by explicitly modeling growth as a function of environmental conditions and using sensitivity analyses to predict likely evolutionary endpoints under changed environments. We conclude that the greatest management concern with respect to preserving anadromy is reduced survival of emigrating smolts, although large changes in freshwater survival or growth rates are potentially also important. We also demonstrate the importance of considering asymptotic size along with maximum growth rate.

Satterthwaite, William H; Beakes, Michael P; Collins, Erin M; Swank, David R; Merz, Joseph E; Titus, Robert G; Sogard, Susan M; Mangel, Marc

2010-01-01

366

Foraminifera and paleoenvironments in the Etchegoin and lower San Joaquin Formations, west-central San Joaquin valley, California  

SciTech Connect

The Etchegoin and San Joaquin formations preserve a rich stratigraphic record of paleoenvironments, deposition, and tectonics during the late Miocene-Pliocene development of the San Joaquin basin. The distribution of foraminifera within these formations can help constrain this record, which includes final filling of the basin, facies responses to sea level changes, and active movement on the San Andreas fault system. The distribution of foraminifera in core samples is analyzed from seven wells along the west-central San joaquin basin - four from Buena Vista oil field, one from western Elk Hills oil field, and two from an area just south of South Belridge oil field. A model of modern, shallow- to marginal-marine foraminiferal biofacies is used to interpret the Etchegoin-San Joaquin faunal distributions. This modern model distinguishes marsh, tidal channel, intertidal, lagoonal, littoral, and shallow sublittoral environments. Ongoing work calibrating this foraminiferal record to the lithologic and macrofossil records in addition to interpreted depositional systems within these formations will further define relationships between paleoenvironments, relative sea level, and tectonics.

Lagoe, M.B.; Tenison, J.A.; Buehring, R. (Univ. of Texas, Austin (United States))

1991-02-01

367

Hydrologic connections of a stream aquifer-vegetation zone in south-central Platte River valley, Nebraska  

NASA Astrophysics Data System (ADS)

Field investigation and numerical modeling approaches were used to examine the hydrologic relations between the Platte River and the adjacent alluvial aquifer and riparian zone in south-central Nebraska. Field methods include direct-push techniques for coring and electric logging in the river channel, permeameter tests for estimating the hydraulic conductivity of the streambed, and monitoring of groundwater levels responding to changes in stream stages and to groundwater evapotranspiration. The channel sediments consist mostly of coarse sand and gravels at the study site with large values of horizontal and vertical hydraulic conductivity. Groundwater in the riparian zone responded nearly simultaneously to the changes in stream stages, and diurnal fluctuations of the water table are correlated with fluctuations of stream stage in summer. All these indicate a well-connected river-aquifer-vegetation hydrologic system. Numerical models, based on the Galerkin finite element method, were developed to construct detailed flow nets for examining the changes in the patterns of groundwater flow dynamics resulting from the use of groundwater and stream water by riparian vegetation. Simulation results suggest that a number of hydrologic factors, such as the thickness of the aquifer and vertical anisotropy of aquifer hydraulic conductivity, also affect the flow patterns. Vertical flow is a major component, more significant than the horizontal flow below the river and the vegetation zone in the growing season. Groundwater evapotranspiration can bring deeper groundwater to the water table by hydraulic lift. This function of riparian vegetation could cause a complicated situation in an investigation of groundwater quality in riparian zones.

Chen, Xunhong

2007-02-01