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Full-Text Articles in Physical Sciences and Mathematics
Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System. 3. Source Of Water Vapor Overlying Pyramid Lake, Larry Benson, J. W. C. White
Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System. 3. Source Of Water Vapor Overlying Pyramid Lake, Larry Benson, J. W. C. White
United States Geological Survey: Staff Publications
During 1988 and 1989, a series of water-vapor extractions were conducted in the Pyramid Lake basin to determine the source of moisture that overlies the lake. Calculations of the isotopic and water-vapor balances were made from isotopic and meteorological data from the Pyramid Lake and Reno, Nevada, areas. The results indicate that in the warm season, most of the moisture that overlies the lake is derived from evaporation as opposed to advected moisture. Isotopic fluxes at the lake surface can be approximated by climatic data from the lake site, which simplifies the calculation of this input in numerical simulations of …
Initial Reference Models In Local Earthquake Tomography, E. Kissling, W. L. Ellsworth, D. Eberhart-Phillips, U. Kradolfer
Initial Reference Models In Local Earthquake Tomography, E. Kissling, W. L. Ellsworth, D. Eberhart-Phillips, U. Kradolfer
United States Geological Survey: Staff Publications
The inverse problem of three-dimensional (3-D) local earthquake tomography is formulated as a linear approximation to a nonlinear function. Thus the solutions obtained and the reliability estimates depend on the initial reference model. Inappropriate models may result in artifacts of significant amplitude. Here, we advocate the application of the same inversion formalism to determine hypocenters and one-dimensiona(1-D) velocity model parameters, including station corrections, as the first step in the 3-D modeling process. We call the resulting velocity model the minimum 1-D model. For test purposes, synthetic data set based on the velocity structure of the San Andreas fault zone in …
A Metapopulation Approach To Pitcher's Thistle (Cirsium Pitcheri) Recovery In Southern Lake Michigan Dunes, A. Kathryn Mceachern, Marlin L. Bowles, Noel B. Pavlovic
A Metapopulation Approach To Pitcher's Thistle (Cirsium Pitcheri) Recovery In Southern Lake Michigan Dunes, A. Kathryn Mceachern, Marlin L. Bowles, Noel B. Pavlovic
United States Geological Survey: Staff Publications
Successful recovery planning for a rare species relies upon knowledge of its life history and ecology, as well as an understanding of its habitat requirements and disturbance regime (Gilpin & Soule 1986, Lande 1988a). Species that depend upon early-successional or transient habitats in landscape mosaics present unique recovery challenges (Menges 1990). They require perpetuation of multiple populations within a shifting mosaic of local habitats. Recovery plans for these species must be formulated from an understanding of population demography within the context of community and landscape dynamics. Processes that maintain landscape mosaics must be given long-term protection if recovery is to …
Geochemical Evidence Of Saharan Dust Parent Material For Soils Developed On Quaternary Limestones Of Caribbean And Western Atlantic Islands, Daniel R. Muhs, Charles A. Bush, Kathleen C. Stewart, Tracy R. Rowland, Russell C. Crittenden
Geochemical Evidence Of Saharan Dust Parent Material For Soils Developed On Quaternary Limestones Of Caribbean And Western Atlantic Islands, Daniel R. Muhs, Charles A. Bush, Kathleen C. Stewart, Tracy R. Rowland, Russell C. Crittenden
United States Geological Survey: Staff Publications
Most previous workers have regarded the insoluble residues of high-purity Quatemary limestones (coral reefs and oolites) as the most important parent material for well-developed, clay-rich soils on Caribbean and western Atlantic islands, but this genetic mechanism requires unreasonable amounts of limestone solution in Quatemary time. Other possible parent materials from external sources are volcanic ash from the Lesser Antilles island arc and Saharan dust carried across the Atlantic Ocean on the northeast trade winds. Soils on Quatemary coral terraces and carbonate eolianites on Barbados, Jamaica, the Florida Keys (United States), and New Providence Island (Bahamas) were studied to determine which, …
Herbicide Interchange Between A Stream And The Adjacent Alluvial Aquifer, Wuncheng Wang, Paul Squillace
Herbicide Interchange Between A Stream And The Adjacent Alluvial Aquifer, Wuncheng Wang, Paul Squillace
United States Geological Survey: Staff Publications
Herbicide interchange between a stream and the adjacent alluvial aquifer and quantification of herbicide bank storage during high streamflow were investigated at a research site on the Cedar River flood plain, 10 km southeast of Cedar Rapids, Iowa. During high streamflow in March 1990, alachlor, atrazine, and metolachlor were detected at concentrations above background in water from wells as distant as 20, 50, and 10 m from the river’s edge, respectively. During high streamflow in May 1990, alachlor, atrazine, cyanazine, and metolachlor were detected at concentrations above background as distant as 20, 50, 10, and 20 m from the river’s …
Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson
Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System, 2. A Predictive Model Of Δ18O And Δ2H In Pyramid Lake, S. W. Hostetler, Larry Benson
United States Geological Survey: Staff Publications
A physically based model of variations in δ18O and δ2H in Pyramid Lake is presented. For inputs, the model uses measurements of liquid water inflows and outflows and their associated isotopic compositions and a set of meteorological data (radiative fluxes, air temperature, relative humidity, and windspced). The model simulates change of lake volume, thermal and isotopic stratification, evaporation, and the isotopic composition of evaporation. A validation of the model for 1987-1989 and 1991 indicates that it can reproduce measured intra- and interannual variations of δ18O and δ2H. Three applications of the model …
Stable Isotopes Of Oxygen And Hydrogen In The Truckee River-Pyramid Lake Surface-Water System. 1. Data Analysis And Extraction Of Paleoclimatic Information, Larry Benson
United States Geological Survey: Staff Publications
The δ18O content of streamflow discharge entering Pyramid Lake is a simple mixture of isotopically enriched Lake Tahoe discharge and isotopically depleted snowmelt. The δ18O value of Pyramid Lake water varies continuously, as isotopically depleted water evaporates from the epilimnion and isotopically depicted water enters the lake as streamflow discharge and on-lake precipitation. In a normal water year, the δ18O of Pyramid Lake surface water varies seasonally because the components of the hydrologic balance in the Pyramid Lake system are seasonally shifted. The problem of isotopic and thermal heterogeneity can be minimized by analyzing …
Effects Of Lithology And Depth On The Permeability Of Core Samples From The Kola And Ktb Drill Holes, C. Morrow, D. Lockner, S. Hickman, M. Rusanov, T. Röckel
Effects Of Lithology And Depth On The Permeability Of Core Samples From The Kola And Ktb Drill Holes, C. Morrow, D. Lockner, S. Hickman, M. Rusanov, T. Röckel
United States Geological Survey: Staff Publications
Permeability measurements were conducted on intact core samples from
the Kola drill hole in Russia and the KTB drill hole in Germany. Samples included granodiorite gneisses, basalts and amphibolites from depths up to 11 km. The tests were intended to determine the pressure sensitivity of permeability and to compare the effects of stress relief and thermal microcracking on the matrix permeability of different rock types and similar samples from different depths. The pore pressure Pp was fixed at the estimated in situ pressure assuming a normal hydrostatic gradient;
the confining pressure Pc was varied to produce effective pressures(P …
Ultrasonic Velocities In Cores From The Kola Superdeep Well And The Nature Of Subhorizontal Seismic Reflections, Lev Vernik, Stephen Hickman, David Lockner, Michael Rusanov
Ultrasonic Velocities In Cores From The Kola Superdeep Well And The Nature Of Subhorizontal Seismic Reflections, Lev Vernik, Stephen Hickman, David Lockner, Michael Rusanov
United States Geological Survey: Staff Publications
P wave velocity and orthogonally polarized S wave velocities were
measured on 12 cores recovered from the Kola superdeep well at depths of 0 to 12 km. Measurements were made along the core axis at a frequency of 1 MHz, at confiningp ressures ranging from 2 to 100 MPa, and under dry and water-saturated conditions. Cores were chosen to sample a variety of lithologies and were used to estimate interval velocities based on a simplified geological column of the well. These interval velocities were then compared with sonic log and vertical seismic profile (VSP) data. High-pressure lab velocities correlated primarily …
Thorium-230 Ages Of Corals And Duration Of The Last Interglacial Sea-Level High Stand On Oahu, Hawaii, Barney J. Szabo, Kenneth R. Ludwig, Daniel R. Muhs, Kathleen R. Simmons
Thorium-230 Ages Of Corals And Duration Of The Last Interglacial Sea-Level High Stand On Oahu, Hawaii, Barney J. Szabo, Kenneth R. Ludwig, Daniel R. Muhs, Kathleen R. Simmons
United States Geological Survey: Staff Publications
Thorium-230 ages of emergent marine deposits on Oahu, Hawaii, have a uniform dis- tribution of ages from ~114,000 to ~131,000 years, indicating a duration for the last interglacial sea-level high stand of ~17,000 years, in contrast to a duration of ~8000 years inferred from the orbitally tuned marine oxygen isotope record. Sea level on Oahu rose to ≥1 to 2 meters higher than present by 131,000 years ago or ~6000 years earlier than inferred from the marine record. Although the latter record suggests a shift back to glacial conditions beginning at ~119,000 years ago, the Oahu coral ages indicate a …