Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana
D.J. Schnoebelen, N.C. Krothe
1999, Groundwater (37) 194-203
The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were...
Wave-propagation formulation of seismic response of multistory buildings
E. Safak
1999, Journal of Structural Engineering (125) 426-437
This paper presents a discrete-time wave-propagation method to calculate the seismic response of multistory buildings, founded on layered soil media and subjected to vertically propagating shear waves. Buildings are modeled as an extension of the layered soil media by considering each story as another layer in the wave-propagation path. The...
Interaction of tectonic and depositional processes that control the evolution of the Iberian Gulf of Cadiz margin
A. Maldonado, C.H. Nelson
1999, Marine Geology (155) 217-242
This study provides an integrated view of the growth patterns and factors that controlled the evolution of the Gulf of Cadiz continental margin based on studies of the tectonic, sedimentologic and oceanographic history of the area. Seven sedimentary regimes are identified, but there are more extensive descriptions of the late...
Nitrogen mineralization in a mature boreal forest, Isle Royale, Michigan
R. Stottlemyer, D. Toczydlowski
1999, Conference Paper, Journal of Environmental Quality
The 115-ha boreal Wallace Lake watershed, located on Isle Royale in the Lake Superior Basin, receives moderate anthropogenic atmospheric N inputs (3 kg ha-1 yr-1). Ecosystem response to atmospheric N inputs is, in part, determined by internal production and consumption of this limiting nutrient. The objectives of this 2-yr study...
Seafloor environments in the Long Island Sound estuarine system
H.J. Knebel, R. P. Signell, R.R. Rendigs, L.J. Poppe, J. H. List
1999, Marine Geology (155) 277-318
Four categories of modern seafloor sedimentary environments have been identified and mapped across the large, glaciated, topographically complex Long Island Sound estuary by means of an extensive regional set of sidescan sonographs, bottom samples, and video-camera observations and supplemental marine-geologic and modeled physical-oceanographic data. (1) Environments of erosion or nondeposition...
Observations on the palynology, petrography and geochemistry of the Western Kentucky number 4 coal bed
C.F. Eble, S.F. Greb, D.A. Williams, J.C. Hower
1999, International Journal of Coal Geology (39) 121-139
Eight bench-column samples of the Western Kentucky Number 4 coal bed, collected from an area along the southern margin of the Western Kentucky Coal Field, were analyzed palynologically, petrographically, and geochemically to document both temporal and spatial variability among these parameters. The Western Kentucky Number 4 coal occurs near the...
Depositional and diagenetic history and petroleum geology of the Jurassic Norphlet Formation of the Alabama coastal waters area and adjacent federal waters area
R.L. Kugler, R.M. Mink
1999, Marine Georesources and Geotechnology (17) 215-232
The discovery of deep (>20,000 ft) gas reservoirs in eolian sandstone of the Upper Jurassic Norphlet Formation in Mobile Bay and offshore Alabama in the late 1970s represents one of the most significant hydrocarbon discoveries in the nation during the past several decades. Estimated original proved gas from Norphlet reservoirs...
Transport and attenuation of carboxylate-modified latex microspheres in fractured rock laboratory and field tracer tests
M.W. Becker, P.W. Reimus, P. Vilks
1999, Ground Water (37) 387-395
Understanding colloid transport in ground water is essential to assessing the migration of colloid‐size contaminants, the facilitation of dissolved contaminant transport by colloids, in situ bioremediation, and the health risks of pathogen contamination in drinking water wells. Much has been learned through laboratory and field‐scale colloid...
Lead isotope compositions of Late Cretaceous and early Tertiary igneous rocks and sulfide minerals in Arizona: Implications for the sources of plutons and metals in porphyry copper deposits
R. M. Bouse, J. Ruiz, S.R. Titley, R. M. Tosdal, J. L. Wooden
1999, Economic Geology (94) 211-244
Porphyry copper deposits in Arizona are genetically associated with Late Cretaceous and early Tertiary igneous complexes that consist of older intermediate volcanic rocks and younger intermediate to felsic intrusions. The igneous complexes and their associated porphyry copper deposits were emplaced into an Early Proterozoic basement characterized by different rocks, geologic...
Preliminary results on photometric properties of materials at the Sagan Memorial Station, Mars
Jeffrey R. Johnson, Randolph L. Kirk, Laurence A. Soderblom, Lisa R. Gaddis, Robert J. Reid, Daniel T. Britt, Peter Smith, Mark T. Lemmon, Nicolas Thomas, James F. Bell III, Nathan T. Bridges, Robert Anderson, Kenneth E. Herkenhoff, Justin N. Maki, Scott L. Murchie, Andreas Dummel, Ralf Jaumann, Frank Trauthan, Gabriele Arnold
1999, Journal of Geophysical Research E: Planets (104) 8809-8830
Reflectance measurements of selected rocks and soils over a wide range of illumination geometries obtained by the Imager for Mars Pathfinder (IMP) camera provide constraints on interpretations of the physical and mineralogical nature of geologic materials at the landing site. The data sets consist of (1) three small “photometric spot”...
Component flow processes at four streams in the Catskill Mountains, New York, analysed using episodic concentration/discharge relationship
C. Evans, T.D. Davies, Peter S. Murdoch
1999, Hydrological Processes (13) 563-575
Plots of solute concentration against discharge have been used to relate stream hydrochemical variations to processes of flow generation, using data collected at four streams in the Catskill Mountains, New York, during the Episodic Response Project of the US Environmental Protection Agency. Results suggest that a two-component system of shallow...
Assessment of Mars Pathfinder landing site predictions
M.P. Golombek, H. J. Moore, A. F. C. Haldemann, T. J. Parker, J. T. Schofield
1999, Journal of Geophysical Research E: Planets (104) 8585-8594
Remote sensing data at scales of kilometers and an Earth analog were used to accurately predict the characteristics of the Mars Pathfinder landing site at a scale of meters. The surface surrounding the Mars Pathfinder lander in Ares Vallis appears consistent with orbital interpretations, namely, that it would be a...
Effects of environmental change on plant species density: Comparing predictions with experiments
L. Gough, J.B. Grace
1999, Ecology (80) 882-890
Ideally, general ecological relationships may be used to predict responses of natural communities to environmental change, but few attempts have been made to determine the reliability of predictions based on descriptive data. Using a previously published structural equation model (SEM) of descriptive data from a coastal marsh landscape, we compared...
Geologic continuous casting below continental and deep-sea detachment faults and at the striated extrusion of Sacsayhuaman, Peru
J.E. Spencer
1999, Geology (27) 327-330
In one common type of industrial continuous casting, partially molten metal is extruded from a vessel through a shaped orifice called a mold in which the metal assumes the cross-sectional form of the mold as it cools and solidifies. Continuous casting can be...
Coupling groundwater and riparian vegetation models to assess effects of reservoir releases
Abraham E. Springer, Julie M. Wright, Patrick B. Shafroth, Juliet C. Stromberg, Duncan T. Patten
1999, Water Resources Research (35) 3621-3630
Although riparian areas in the arid southwestern United States are critical for maintaining species diversity, their extent and health have been declining since Euro‐American settlement. The purpose of this study was to develop a methodology to evaluate the potential for riparian vegetation restoration and groundwater recharge. A numerical groundwater flow...
CFIRP: What we learned in the first ten years
C. L. Chambers, W.C. McComb, J. C. Tappeiner II, L.D. Kellogg, R.L. Johnson, G. Spycher
1999, Conference Paper, Forestry Chronicle
In response to public dissatisfaction with forest management methods, we initiated the College of Forestry Integrated Research Project (CFIRP) to test alternative silvicultural systems in Douglas-fir (Pseudotsuga menziesii stands in western Oregon. We compared costs and biological and human responses among a control and three replicated silvicultural alternatives to clearcutting...
Estimating lake-atmosphere CO2 exchange
D.E. Anderson, Robert G. Striegl, D.I. Stannard, C.M. Michmerhuizen, T.A. McConnaughey, J. W. LaBaugh
1999, Limnology and Oceanography (44) 988-1001
Lake‐atmosphere CO2 flux was directly measured above a small, woodland lake using the eddy covariance technique and compared with fluxes deduced from changes in measured lake‐water CO2 storage and with flux predictions from boundary‐layer and surface‐renewal models. Over a 3‐yr period, lake‐atmosphere exchanges of CO2 were measured over 5 weeks...
Factors controlling the establishment of Fremont cottonwood seedlings on the Upper Green River, USA
David J. Cooper, David M. Merritt, Douglas C. Andersen, Rodney A. Chimner
1999, Regulated Rivers: Research & Management (15) 419-440
Declines in cottonwood (Populus spp.) recruitment along alluvial reaches of large rivers in arid regions of the western United States have been attributed to modified flow regimes, lack of suitable substrate, insufficient seed rain, and increased interspecific competition. We evaluated whether and how these factors were operating during 1993–1996 to influence...
A method for nitrate collection for δ15N and δ18O analysis from waters with low nitrate concentrations
Cecily C.Y. Chang, J. Langston, M. Riggs, K. Campbell, S. R. Silva, C. Kendall
1999, Canadian Journal of Fisheries and Aquatic Sciences (56) 1856-1864
Recently, methods have been developed to analyze NO3- for δ15N and δ18O, improving our ability to identify NO3- sources and transformations. However, none of the existing methods are suited for waters with low NO3- concentrations (0.7-10 µM). We describe an improved method for collecting and recovering NO3- on exchange columns....
Estimation of near-surface shear-wave velocity by inversion of Rayleigh waves
J. Xia, R. D. Miller, C.B. Park
1999, Geophysics (64) 691-700
The shear‐wave (S-wave) velocity of near‐surface materials (soil, rocks, pavement) and its effect on seismic‐wave propagation are of fundamental interest in many groundwater, engineering, and environmental studies. Rayleigh‐wave phase velocity of a layered‐earth model is a function of frequency and four groups...
Development of a comprehensive watershed model applied to study stream yield under drought conditions
S.P. Perkins, M. Sophocleous
1999, Groundwater (37) 418-426
We developed a model code to simulate a watershed's hydrology and the hydraulic response of an interconnected stream-aquifer system, and applied the model code to the Lower Republican River Basin in Kansas. The model code links two well-known computer programs: MODFLOW (modular 3-D flow...
A topological system for delineation and codification of the Earth's river basins
K.L. Verdin, J. P. Verdin
1999, Journal of Hydrology (218) 1-12
A comprehensive reference system for the Earth's river basins is proposed as a support to fiver basin management, global change research, and the pursuit of sustainable development. A natural system for delineation and codification of basins is presented which is based upon topographic control and the topology of the fiver...
Coseismic slip resolution along a plate boundary megathrust: the Nankai Trough, southwest Japan
Takeshi Sagiya, Wayne Thatcher
1999, Journal of Geophysical Research B: Solid Earth (104) 1111-1129
Geodetic survey measurements are used to estimate the coseismic slip distribution in the 1944 Tonankai (Mw=8.1) and 1946 Nankaido (Mw=8.3) earthquakes and to assess quantitatively the degree to which this slip is resolved on the plate boundary megathrust. Data used include 798 angle changes from triangulation surveys, 328 leveling section...
Regional Vp, Vs, Vp/Vs, and Poisson's ratios across earthquake source zones from Memphis, Tennessee, to St. Louis, Missouri
R. D. Catchings
1999, Bulletin of the Seismological Society of America (89) 1591-1605
Models of P- and S-wave velocity, Vp/Vs ratios, Poisson's ratios, and density for the crust and upper mantle are presented along a 400-km-long profile trending from Memphis, Tennessee, to St. Louis, Missouri. The profile crosses the New Madrid seismic zone and reveals distinct regional variations in the crustal velocity structure...
Spatial distribution of Serengeti wildebeest in relation to resources
J.F. Wilmshurst, J. M. Fryxell, Brian P. Farm, A.R.E. Sinclair, C.P. Henschel
1999, Canadian Journal of Zoology (77) 1223-1232
We investigated the spatial distribution of radio-marked wildebeest (Connochaetes taurinus) in the Serengeti ecosystem in relation to the distribution of their food resources, comparing patterns in the wet and dry seasons and at local and landscape spatial scales. A mechanistic model of ruminant energy optimization predicted that wildebeest should maximize...
