XRD measurement of mean thickness, thickness distribution and strain for illite and illite-smectite crystallites by the Bertaut-Warren-Averbach technique
Victor A. Drits, Dennis D. Eberl, Jan Srodon
1998, Clays and Clay Minerals (46) 38-50
A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949, 1950; Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions for calculated and experimental XRD...
Caribou distribution during the post-calving period in relation to infrastructure in the Prudhoe Bay oil field, Alaska
Matthew A. Cronin, Steven C. Amstrup, George M. Durner, Lynn E. Noel, Trent L. McDonald, Warren B. Ballard
1998, Arctic (51) 85-93
There is concern that caribou (Rangifer tarandus) may avoid roads and facilities (i.e., infrastructure) in the Prudhoe Bay oil field (PBOF) in northern Alaska, and that this avoidance can have negative effects on the animals. We quantified the relationship between caribou distribution and PBOF infrastructure during the post-calving period (mid-June...
Dating previously balanced rocks in seismically active parts of California and Nevada
J. W. Bell, J.N. Brune, T. Liu, M. Zreda, J. C. Yount
1998, Geology (26) 495-498
Precariously balanced boulders that could be knocked down by strong earthquake ground motion are found in some seismically active areas of southern California and Nevada. In this study we used two independent surface-exposure dating techniques—rock-varnish microlamination and cosmogenic 36Cl dating methodologies—to estimate minimum- and...
Terrestrial sedimentation and the carbon cycle: Coupling weathering and erosion to carbon burial
Robert F. Stallard
1998, Global Biogeochemical Cycles (12) 231-257
This paper examines the linkages between the carbon cycle and sedimentary processes on land. Available data suggest that sedimentation on land can bury vast quantities of organic carbon, roughly 1015 g C yr−1. To evaluate the relative roles of various classes of processes in the burial of carbon on land, terrestrial...
Late Quaternary slip on the Santa Cruz Island fault, California
N. Pinter, S.B. Lueddecke, E.A. Keller, K. R. Simmons
1998, Geological Society of America Bulletin (110) 711-722
The style, timing, and pattern of slip on the Santa Cruz Island fault were investigated by trenching the fault and by analysis of offset late Quaternary landforms. A trench excavated across the fault at Christi Beach, on the western coast of the island,...
ASTER preflight and inflight calibration and the validation of level 2 products
K. Thome, K. Aral, S. Hook, H. Kieffer, H. Lang, T. Matsunaga, A. Ono, F. D. Palluconi, H. Sakuma, P. Slater, T. Takashima, H. Tonooka, S. Tsuchida, R.M. Welch, E. Zalewski
1998, IEEE Transactions on Geoscience and Remote Sensing (36) 1161-1172
Describes the preflight and inflight calibration approaches used for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The system is a multispectral, high-spatial resolution sensor on the Earth Observing System's EOS-AM1 platform. Preflight calibration of ASTER uses well-characterized sources to provide calibration and preflight round-robin exercises to understand biases...
Singularity and Nonnormality in the Classification of Compositional Data
Geoffrey C. Bohling, J.C. Davis, Ricardo A. Olea, Jan Harff
1998, Mathematical Geology (30) 5-20
Geologists may want to classify compositional data and express the classification as a map. Regionalized classification is a tool that can be used for this purpose, but it incorporates discriminant analysis, which requires the computation and inversion of a covariance matrix. Covariance matrices of compositional data always will be singular...
Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia
Niel Plummer, E. Busenberg, J. B. McConnell, S. Drenkard, P. Schlosser, R. L. Michel
1998, Applied Geochemistry (13) 995-1015
The quality of water in the Upper Floridan aquifer near Valdosta, Georgia is affected locally by discharge of Withlacoochee River water through sinkholes in the river bed. Data on transient tracers and other dissolved substances, including Cl−, 3H, tritiogenic helium-3 (3He), chlorofluorocarbons (CFC-11, CFC-12,...
Closing the gap between regional and global travel time tomography
H. Bijwaard, W. Spakman, E.R. Engdahl
1998, Journal of Geophysical Research B: Solid Earth (103) 30055-30078
Recent global travel time tomography studies by Zhou [1996] and van der Hilst et al. [1997] have been performed with cell parameterizations of the order of those frequently used in regional tomography studies (i.e., with cell sizes of 1°–2°). These new global models constitute a considerable improvement over previous results that were obtained...
Estimation of the depth to the fresh-water/salt-water interface from vertical head gradients in wells in coastal and island aquifers
S. K. Izuka, S. B. Gingerich
1998, Hydrogeology Journal (6) 365-373
An accurate estimate of the depth to the theoretical interface between fresh, water and salt water is critical to estimates of well yields in coastal and island aquifers. The Ghyben–Herzberg relation, which is commonly used to estimate interface depth, can greatly underestimate or overestimate the fresh-water...
Waveform inversion of very long period impulsive signals associated with magmatic injection beneath Kilauea Volcano, Hawaii
T. Ohminato, B. A. Chouet, P. Dawson, S. Kedar
1998, Journal of Geophysical Research B: Solid Earth (103) 23839-23862
We use data from broadband seismometers deployed around the summit of Kilauea Volcano to quantify the mechanism associated with a transient in the flow of magma feeding the east rift eruption of the volcano. The transient is marked by rapid inflation of the Kilauea summit peaking at 22 μrad 4.5...
The National Water Data Exchange-capabilities and trends in the dissemination and exchange of water data
J.S. Burton
1998, IAHS-AISH Publication 237-248
This paper discusses the programmes of the National Water Data Exchange (NAWDEX) in providing access to US Geological Survey (USGS) water data and water-related information. NAWDEX dissseminates water data and water-related information by working cooperatively through a network of 68 Assistance Centers to more than 430 member organizations. In addition,...
An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs
E. Udegbunam, J.O. Amaefule
1998, Journal of Petroleum Science and Engineering (21) 143-152
An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the...
Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine volcanic field, California
R. E. Arvidson, C. Acton, D. Blaney, J. Bowman, S. Kim, G. Klingelhofer, J. Marshall, C. Niebur, J. Plescia, R.S. Saunders, C.T. Ulmer
1998, Journal of Geophysical Research E: Planets (103) 22671-22688
Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover-based, long-distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57Fe Mössbauer and nuclear magnetic resonance spectrometers for in situ...
Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina
J.M. Rine, R. C. Berg, J.M. Shafer, E.R. Covington, J.K. Reed, C.B. Bennett, J.E. Trudnak
1998, Environmental Geology (35) 263-277
A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in South Carolina. A Geographic Information System (GIS) was used to integrate...
Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins
K. L. Tanaka, J. M. Dohm, J.H. Lias, T.M. Hare
1998, Journal of Geophysical Research E: Planets (103) 31407-31419
Analysis of erosional valleys, geologic materials and features, and topography through time in the Thaumasia region of Mars using co-registered digital spatial data sets reveals significant associations that relate to valley origin. Valleys tend to originate (1) on Noachian to Early Hesperian (stages 1 and 2) large volcanoes, (2) within...
Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology
Greg A. Ludvigson, Luis A. Gonzalez, R.A. Metzger, B.J. Witzke, Richard L. Brenner, A.P. Murillo, T. S. White
1998, Geology (26) 1039-1042
Sphaerosiderite, a morphologically distinct millimeter-scale spherulitic siderite (FeCO3), forms predominantly in wetland soils and sediments, and is common in the geologic record. Ancient sphaerosiderites are found in paleosol horizons within coal-bearing stratigraphic intervals and, like their modern counterparts, are interpreted as having formed...
Use of indicator items to monitor marine debris on a New Jersey beach from 1991 to 1996
C. A. Ribic
1998, Marine Pollution Bulletin (36) 887-891
The US National Marine Debris Monitoring Program is using indicator items from beach surveys to identify whether amounts of marine debris are changing over time. Indicator items were selected through expert opinion and assumed to reflect the trend of all debris. We used monthly data from a 1991-1996 study of...
Plant taphonomy in incised valleys: Implications for interpreting paleoclimate from fossil plants
T.M. Demko, R. F. Dubiel, Judith T. Parrish
1998, Geology (26) 1119-1122
Paleoclimatic interpretations of the Upper Triassic Chinle Formation (Colorado Plateau) based on plants conflict with those based on the sedimentary rocks. The plants are suggestive of a humid, equable climate, whereas the rocks are more consistent with deposition under highly seasonal precipitation and...
Using safety inspection data to estimate shaking intensity for the 1994 Northridge earthquake
K. Thywissen, J. Boatwright
1998, Bulletin of the Seismological Society of America (88) 1243-1253
We map the shaking intensity suffered in Los Angeles County during the 17 January 1994, Northridge earthquake using municipal safety inspection data. The intensity is estimated from the number of buildings given red, yellow, or green tags, aggregated by census tract. Census tracts...
Flow of river water into a karstic limestone aquifer: 2. Dating the young fraction in groundwater mixtures in the Upper Floridan aquifer near Valdosta, Georgia
Niel Plummer, E. Busenberg, S. Drenkard, P. Schlosser, B. Ekwurzel, R. Weppernig, J. B. McConnell, R. L. Michel
1998, Applied Geochemistry (13) 1017-1043
Tritium/helium-3 (3H/3He) and chlorofluorocarbon (CFCs, CFC–11, CFC–12, CFC–113) data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near Valdosta, Georgia, where regional paleowater in the Upper Floridan aquifer receives recharge from two young sources—the flow of Withlacoochee River water through sinkholes in the...
Proxy of monsoon seasonality in carbon isotopes from paleosols of the southern Chinese Loess Plateau
Hongfang Wang, L.R. Follmer
1998, Geology (26) 987-990
Soil organic matter (SOM) and soil carbonate (SC) are common constituents in soils and are directly related to plant growth. SOM accumulates gradually from the decomposition of plant material over time, whereas SC formation is biased to dry-season soil-dissolved CO2 that derives from plant...
Noble gases, stable isotopes, and radiocarbon as tracers of flow in the Dakota aquifer, Colorado and Kansas
J.F. Clark, M.L. Davisson, G.B. Hudson, P. A. Macfarlane
1998, Journal of Hydrology (211) 151-167
A suite of chemical and isotope tracers (dissolved noble gases, stable isotopes of water, radiocarbon, and CI) have been analyzed along a flow path in the Dakota aquifer system to determine likely recharge sources, ground water residence times, and the extent of mixing between local and intermediate flow systems, presumably...
Earthquake triggering by transient and static deformations
J. Gomberg, N.M. Beeler, M.L. Blanpied, P. Bodin
1998, Journal of Geophysical Research B: Solid Earth (103) 24411-24426
Observational evidence for both static and transient near-field and far-field triggered seismicity are explained in terms of a frictional instability model, based on a single degree of freedom spring-slider system and rate- and state-dependent frictional constitutive equations. In this study a triggered earthquake is one whose failure time has been...
Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary
W.J. Kimmerer, J.R. Burau, W.A. Bennett
1998, Limnology and Oceanography (43) 1697-1709
In many estuaries, maxima in turbidity and abundance of several common species of zooplankton occur in the low salinity zone (LSZ) in the range of 0.5-6 practical salinity units (psu). Analysis of zooplankton abundance from monitoring in 1972-1987 revealed that historical maxima in abundance of the copepod Eurytemora affinis and...
