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High-angle faults in the basement of Yucca Flat, Nevada Test Site, Nevada, based on analysis of a constrained gravity inversion surface
Geoffrey A. Phelps, Edwin H. McKee
1999, Open-File Report 99-383
Using a model of the topographic subsurface derived from drill hole and gravity inversion analysis of the basement rocks in Yucca Flat, Nevada Test Site (NTS), Nevada, a fault map and digital fault dataset were constructed based on offsets of the basement surface. Because these faults are, in large part,...
Basic Requirements for Collecting, Documenting, and Reporting Precipitation and Stormwater-Flow Measurements
Peter E. Church, Gregory E. Granato, David W. Owens
1999, Open-File Report 99-255
Accurate and representative precipitation and stormwater-flow data are crucial for use of highway- or urban-runoff study results, either individually or in a regional or national synthesis of stormwater-runoff data. Equally important is information on the level of accuracy and representativeness of this precipitation and stormwaterflow data. Accurate and representative measurements...
Geometry, structure, and concealed lithology of the San Rafael Basin, southeastern Arizona
Mark W. Bultman
1999, Open-File Report 99-399
The contiguous United States has been well explored for exposed conventional mineral deposits. Therefore, it is likely that many economically viable and strategically significant conventional undiscovered mineral deposits will be found in bedrock concealed beneath basin sediments. Mineral resource assessments must incorporate an understanding of the geometry, structure, and concealed...
Inversion of gravity data to define the pre-Tertiary surface and regional structures possibly influencing ground-water flow in the Pahute Mesa-Oasis Valley region, Nye County, Nevada
T.G. Hildenbrand, V.E. Langenheim, E. A. Mankinen, E.H. McKee
1999, Open-File Report 99-49
A three-dimensional inversion of gravity data from the Pahute Mesa–Oasis Valley region reveals a topographically complex pre-Tertiary basement surface. Beneath Pahute Mesa, the thickness of the Tertiary volcanic deposits may exceed 5 km within the Silent Canyon caldera complex. South of Pahute Mesa in Oasis Valley, basement is shallower (<...
Digital Geologic Map of the Wallace 1:100,000 Quadrangle, Idaho
Reed S. Lewis, Russell F. Burmester, Mark D. McFaddan, Pamela D. Derkey, Jon R. Oblad
1999, Open-File Report 99-390
The geology of the Wallace 1:100,000 quadrangle, Idaho was compiled by Reed S. Lewis in 1997 primarily from published materials including 1983 data from Foster, Harrison's unpublished mapping done from 1975 to 1985, Hietenan's 1963, 1967, 1968, and 1984 mapping, Hobbs and others 1965 mapping, and Vance's 1981 mapping, supplemented...
Spatial geologic data model for the Gunnison, Grand Mesa, Uncompahgre National Forests mineral resource assessment area, southwestern Colorado and digital data for the Leadville, Montrose, Durango, and Colorado parts of the Grand Junction, Moab, and Cortez 1° x 2° geologic maps
W. C. Day, G.N. Green, D. H. Knepper Jr., R. C. Phillips
1999, Open-File Report 99-427
The digital geologic and geographic information system (GIS) data presented here were prepared to aid in Grand Mesa, Uncompahgre, Gunnison National Forest (GMUG) mineral resource assessment Project studies by the U.S. Geological Survey Mineral Resource Program. The goals of the GMUG Project is to provide mineral resource data and an...
Neogene-quaternary Ostracoda and paleoenvironments, of the Limón basin, Costa Rica, and Bocas del Toro basin, Panama
P.F. Borne, T. M. Cronin, J. E. Hazel
1999, Bulletins of American Paleontology 231-250
Tropical marine ostracodes from Neogene and Quaternary sediments of the Central American Caribbean region have been the subject of biostratigraphic, ecological, taxonomic, and evolutionary studies. As part of the Panama Paleontology Project (PPP), Neogene and Quaternary ostracodes are being studied from the Central American region. The overall goal of this...
Use of nitrogen isotopes to determine sources of nitrate contamination in two desert basins in California
J.N. Densmore, J.K. Bohlke
1999, IAHS-AISH Publication (260) 63-73
Nitrogen-15/14 isotope ratios (δ15N) were measured in groundwater, infiltrating wastewater, and natural uncontaminated soil to determine the source of high NO3- concentrations in two desert basins at Fort Irwin National Training Center in the Mojave Desert. The abundance and isotopic composition of dissolved nitrogen gas were measured in some of...
Specific conductance, water temperature, and water level data, San Francisco Bay, California, water year 1998
Paul A. Buchanan
1999, Interagency Ecological Program Newsletter (12) 46-53
Specific conductance and water temperature data are continuously recorded at four sites in San Francisco Bay, California: San Pablo Strait at Point San Pablo, Central San Francisco Bay at Presidio Military Reservation, Pier 24 at Bay Bridge, and South San Francisco Bay at San Mateo Bridge near Foster City (Figure...
Pattern and process of land loss in the Mississippi Delta: A spatial and temporal analysis of wetland habitat change
John W. Day, Gary P. Shaffer, Louis D. Britsch, Denise J. Reed, Suzanne Hawes, Donald R. Cahoon
1999, Conference Paper, Recent research in coastal Louisiana : natural system function and response to human influence : a symposium convened by the Louisiana Universities Marine Consortium, February 3-5, 1998, Lafayette, Louisiana
An earlier investigation (Turner 1997) concluded that most of the coastal wetland loss in Louisiana was caused by the effects of canal dredging, that loss was near zero in the absence of canals, and that land loss had decreased to near zero by the late 1990s. This analysis was based...
The ecological condition of estuaries in the Gulf of Mexico
1999, Cooperator Report 620-R-98-004
The Gulf of Mexico is a vast natural resource encompassing the coastal areas of western Florida, Alabama, Mississippi, Louisiana, and Texas, as well as a portion of Mexico. Many estuaries flow into the Gulf of Mexico and serve as nursery grounds for fish, habitat for a wide variety of wildlife,...
Integrated use of continuous seismic-reflection profiling and ground-penetrating radar methods at John's Pond, Cape Cod, Massachusetts
C.J. Powers, F.P. Haeni, S. Smith
1999, Conference Paper, Proceedings of the symposium on the application of geophysics to engineering and environmental problems : March 14-18, 1999, Oakland, CA
Continuous seismic-reflection profiling (CSP) and ground-penetrating radar (GPR) surveys were conducted by the U.S. Geological Survey in April 1998 over the northern part of John’s Pond, a glacial kettle pond southeast of Otis Air National Guard Base, Cape Cod, Massachusetts. The surveys were conducted to delineate the types and...
Tracing sediment dispersal on nourished beaches: Two case studies
E. Robert Thieler, Paul T. Gayes, William C. Schwab, M. Scott Harris
1999, Conference Paper, Coastal Sediments '99
The event- to decade-scale patterns of sediment dispersal on two artificially nourished beaches have been mapped using a combination of geophysical surveys, closely-spaced vibracores, and repeated beach profiles. At both Wrightsville Beach, NC and Folly Island, SC the sediment used for beach nourishment is macroscopically distinct from native sediment and...
Modern accumulation rates and a sediment budget for the Eel shelf: a flood-dominated depositional environment
Christopher K. Sommerfield, Charles A. Nittrouer
1999, Marine Geology (154) 227-241
The northern California continental margin is periodically impacted by geologically significant storms, which have a marked influence on terrigenous sediment supply, flood deposition, and long-term accumulation of fine-grained sediment on the Eel shelf. Accumulation of Eel River muds on the adjacent shelf was investigated using 210Pb and 137Cs geochronologies, in...
Development of a long-term ecological monitoring program in Denali National Park and Preserve, Alaska (USA)
Karen L. Oakley, Edward M. Debevec, Eric A. Rexstad
1999, Conference Paper, Proceedings: North American science symposium: Toward a unified framework for inventorying and monitoring forest ecosystem resources
A Long-term Ecological Monitoring (LTEM) program began at Denali National Park and Preserve, Alaska (USA) in 1992, as a prototype for subarctic parks. The early history of the Denali LTEM program provides insight into the challenges that can arise during monitoring program development. The Denali program has thus far taken...
Chapter 7: Studies of short-lived radionuclides in Santorini volcanics
T. H. Druitt, L. Edwards, R. M. Mellors, D. M. Pyle, R. S. J. Sparks, Marvin A. Lanphere, M. Davies, B. Barreirio
1999, Geological Society, London, Memoirs (19) 118-128
Disequilibria between the short-lived radioactive nuclides 226Ra, 230Th and 238U in young volcanic rocks can be used both for dating the time of crystallisation of a rock, and as isotopic tracers of the sources of magmas and the chemical evolution of volcanic systems. The principles of these methods have been reviewed extensively elsewhere...
Chapter 6 Geochemistry, isotopic composition and petrogenetic modelling of the Thera pyroclastics
T. H. Druitt, L. Edwards, R. M. Mellors, D. M. Pyle, R. S. J. Sparks, Marvin A. Lanphere, M. Davies, B. Barreirio
1999, Geological Society, London, Memoirs (19) 89-116
This chapter examines the major element, trace element, and isotope geochemistry of the Thera pyroclastics, and places it in the context of the geochemical evolution of the whole volcanic field. Geochemical studies to date have been undertaken predominantly on the lavas, and the pyroclastic succession has been relatively neglected. The...