Kinetic and mineralogic controls on the evolution of groundwater chemistry and 87Sr/86Sr in a sandy silicate aquifer, northern Wisconsin, USA
T.D. Bullen, D. P. Krabbenhoft, C. Kendall
1996, Geochimica et Cosmochimica Acta (60) 1807-1821
Substantial flowpath-related variability of 87Sr/86Sr is observed in groundwaters collected from the Trout Lake watershed of northern Wisconsin. In the extensive shallow aquifer composed of sandy glacial outwash, groundwater is recharged either by seepage from lakes or by precipitation that infiltrates the inter-lake uplands. 87Sr/86Sr of groundwater derived mainly as...
Observations and analysis of self-similar branching topology in glacier networks
D.B. Bahr, S.D. Peckham
1996, Journal of Geophysical Research B: Solid Earth (101) 25511-25521
Glaciers, like rivers, have a branching structure which can be characterized by topological trees or networks. Probability distributions of various topological quantities in the networks are shown to satisfy the criterion for self-similarity, a symmetry structure which might be used to simplify future models of glacier dynamics. Two analytical methods...
Estimation of the potential for atrazine transport in a silt loam soil
D. A. V. Eckhardt, R. J. Wagenet
1996, ACS Symposium Series (630) 101-116
The transport potential of the herbicide atrazine (2-chloro-4-ethyl-6-isopropyl-s-triazine) through a 1-meter-thick root zone of corn (Zea mays L.) in a silty-loam soil in Kansas was estimated for a 22-year period (1972-93) using the one-dimensional water-flow and solute-transport model LEACHM. Results demonstrate that, for this soil, atrazine transport is directly related to...
The enigma of the New Madrid earthquakes of 1811-1812
A. C. Johnston, E.S. Schweig
1996, Annual Review of Earth and Planetary Sciences (24) 339-384
Continental North America's greatest earthquake sequence struck on the western frontier of the United States. The frontier was not then California but the valley of the continent's greatest river, the Mississippi, and the sequence was the New Madrid earthquakes of the winter of 1811–1812. Their described impacts on the land...
Identification of groundwater parameters at Columbus, Mississippi, using a 3D inverse flow and transport model
H.C. Barlebo, D. Rosbjerg, M. C. Hill
1996, IAHS-AISH Publication (237) 189-208
An extensive amount of data including hydraulic heads, hydraulic conductivities and concentrations of several solutes from controlled injections have been collected during the MADE 1 and MADE 2 experiments at a heterogeneous site near Columbus, Mississippi. In this paper the use of three-dimensional inverse groundwater models including simultaneous estimation of...
Potential climatic impacts of vegetation change: A regional modeling study
J.H. Copeland, R.A. Pielke, T.G.F. Kittel
1996, Journal of Geophysical Research D: Atmospheres (101) 7409-7418
The human species has been modifying the landscape long before the development of modern agrarian techniques. Much of the land area of the conterminous United States is currently used for agricultural production. In certain regions this change in vegetative cover from its natural state may have led to local climatic...
Experimental investigation and modeling of uranium (VI) transport under variable chemical conditions
M. Kohler, G.P. Curtis, D.B. Kent, J.A. Davis
1996, Water Resources Research (32) 3539-3551
The transport of adsorbing and complexing metal ions in porous media was investigated with a series of batch and column experiments and with reactive solute transport modeling. Pulses of solutions containing U(VI) were pumped through columns filled with quartz grains, and the breakthrough of U(VI) was studied as a function...
Diagenesis, compaction, and fluid chemistry modeling of a sandstone near a pressure seal: Lower Tuscaloosa Formation, Gulf Coast
Suzanne Weedman, Susan L. Brantley, R. Shiraki, Simon R. Poulson
1996, American Association of Petroleum Geologists Bulletin (80) 1045-1063
Petrographic, isotopic, and fluid-inclusion evidence from normally and overpressured sand-stones of the lower Tuscaloosa Formation (Upper Cretaceous) in the Gulf Coast documents quartz-overgrowth precipitation at 90°C or less, calcite cement precipitation at approximately 100° and 135°C, and prismatic quartz cement precipitation at about 125°C. Textural evidence suggests that carbonate cement...
Climate change and northern prairie wetlands: Simulations of long-term dynamics
Karen A. Poiani, W. Carter Johnson, George A. Swanson, Thomas C. Winter
1996, Limnology and Oceanography (41) 871-881
A mathematical model (WETSIM 2.0) was used to simulate wetland hydrology and vegetation dynamics over a 32-yr period (1961–1992) in a North Dakota prairie wetland. A hydrology component of the model calculated changes in water storage based on precipitation, evapotranspiration, snowpack, surface runoff, and subsurface inflow. A spatially explicit vegetation...
Reactive solute transport in acidic streams
R. E. Broshears
1996, Water, Air, & Soil Pollution (90) 195-204
Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model...
Genetic characteristics of fluid inclusions in sphalerite from the Silesian-Cracow ores, Poland
A. Kozlowski, D. L. Leach, J.G. Viets
1996, Prace - Panstwowego Instytutu Geologicznego (154) 72-84
Fluid inclusion studies in sphalerite from early-stage Zn-Pb mineralization in the Silesian-Cracow region (southern Poland), yielded homogenization temperatures (Th) from 80 to 158??C. Vertical thermal gradient of the parent fluids was 6 to 10??C, and the ore crystallization temperature ranges varied from <10??C at deep levels to 25??C at shallow...
Depositional controls on coal distribution and quality in the Eocene Brunner Coal Measures, Buller Coalfield, South Island, New Zealand
R. M. Flores, R. Sykes
1996, International Journal of Coal Geology (29) 291-336
The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal...
Kinematics of the Eastern California shear zone: Evidence for slip transfer from Owens and Saline Valley fault zones to Fish Lake Valley fault zone
M.C. Reheis, T.H. Dixon
1996, Geology (24) 339-342
Late Quaternary slip rates and satellite-based geodetic data for the western Great Basin constrain regional fault-slip distribution and evolution. The geologic slip rate on the Fish Lake Valley fault zone (the northwest extension of the Furnace Creek fault zone) increases northward from about...
A simulation-based approach for designing effective field-sampling programs to evaluate contamination risk of groundwater supplies
R. Nordqvist, C.I. Voss
1996, Hydrogeology Journal (4) 23-39
An approach to model discrimination and network design for evaluation of groundwater contamination risk is proposed and demonstrated by application to a site in a glaciofluvial aquifer in Sweden. The approach consists of first hypothesizing alternative conceptual models of hydrogeology at the site on the basis of both quantitative data...
Age dating of shallow groundwater with chlorofluorocarbons, tritium/helium: 3, and flow path analysis, southern New Jersey coastal plain
Zoltan Szabo, D.E. Rice, Niel Plummer, E. Busenberg, S. Drenkard, P. Schlosser
1996, Water Resources Research (32) 1023-1038
Groundwater age dating through the combination of transient tracer methods (chlorofluorocarbons (CFCs) and tritium/helium 3 (3H/3He)) and groundwater flow path analysis is useful for investigating groundwater travel times, flow patterns, and recharge rates, as demonstrated by this study of the homogeneous shallow, unconfined Kirkwood-Cohansey aquifer system in the southern New...
Implications of fault constitutive properties for earthquake prediction
James H. Dieterich, B. Kilgore
1996, Conference Paper, Proceedings of the National Academy of Sciences of the United States of America
The rate- and state-dependent constitutive formulation for fault slip characterizes an exceptional variety of materials over a wide range of sliding conditions. This formulation provides a unified representation of diverse sliding phenomena including slip weakening over a characteristic sliding distance D(c), apparent fracture energy at a rupture front, time- dependent...
Integrating a geographic information system, a scientific visualization system, and a precipitation model
L.E. Hay, L.K. Knapp
1996, Water Resources Bulletin (32) 357-369
Investigating natural, potential, and human-induced impacts on hydrologic systems commonly requires complex modeling with overlapping data requirements, plus massive amounts of one- to four-dimensional data at multiple scales and formats. Given the complexity of most hydrologic studies, the requisite software infrastructure must incorporate many components including simulation modeling and spatial...
The initial cooling of pahoehoe flow lobes
L. Keszthelyi, R. Denlinger
1996, Bulletin of Volcanology (58) 5-18
In this paper we describe a new thermal model for the initial cooling of pahoehoe lava flows. The accurate modeling of this initial cooling is important for understanding the formation of the distinctive surface textures on pahoehoe lava flows as well as being the first step in modeling such key...
Semivariogram modeling by weighted least squares
X. Jian, Ricardo A. Olea, Y.-S. Yu
1996, Computers & Geosciences (22) 387-397
Permissible semivariogram models are fundamental for geostatistical estimation and simulation of attributes having a continuous spatiotemporal variation. The usual practice is to fit those models manually to experimental semivariograms. Fitting by weighted least squares produces comparable results to fitting manually in less time, systematically, and provides an Akaike information criterion...
Granular-flow rheology: Role of shear-rate number in transition regime
Chiu-Lan Chen, C. #NAME? Ling
1996, Journal of Engineering Mechanics (122) 469-479
This paper examines the rationale behind the semiempirical formulation of a generalized viscoplastic fluid (GVF) model in the light of the Reiner-Rivlin constitutive theory and the viscoplastic theory, thereby identifying the parameters that control the rheology of granular flow. The shear-rate number ( N ) proves to be among the most significant...
Groundwater inflow measurements in wetland systems
Randy J. Hunt, David P. Krabbenhoft, Mary P. Anderson
1996, Water Resources Research (32) 495-507
Our current understanding of wetlands is insufficient to assess the effects of past and future wetland loss. While knowledge of wetland hydrology is crucial, groundwater flows are often neglected or uncertain. In this paper, groundwater inflows were estimated in wetlands in southwestern Wisconsin using traditional Darcy's law calculations and three...
Failure in laboratory fault models in triaxial tests
J.C. Savage, D.A. Lockner, J.D. Byerlee
1996, Journal of Geophysical Research B: Solid Earth (101) 22215-22224
A model of a fault in the Earth is a sand-filled saw cut in a granite cylinder subjected to a triaxial test. The saw cut is inclined at an angle α to the cylinder axis, and the sand filling is intended to represent gouge. The triaxial test subjects the granite...
Mn-rich ilmenite from the Sullivan Pb-Zn-Ag deposit, British Columbia
S.-Y. Jiang, M. R. Palmer, J. F. Slack
1996, Canadian Mineralogist (34) 29-36
Electron-microprobe analyses of 76 ilmenite grains from 13 locations in the footwall, hanging wall, and ore zone of the Sullivan Pb-Zn-Ag deposit, Kimberley, British Columbia, and from regionally developed tourmalinite of the Middle Proterozoic Aldridge Formation show two different modes that reflect two stages of formation. The first stage of...
NLEAP/GIS approach for identifying and mitigating regional nitrate-nitrogen leaching
M.J. Shaffer, M.D. Hall, B.K. Wylie, D.G. Wagner
D.L. Corwin, K. Loague, editor(s)
1996, Book chapter, Applications of GIS to the modeling of non-point source pollutants in the vadose zone, SSSA Special Publication 48
Improved simulation-based methodology is needed to help identify broad geographical areas where potential NO3-N leaching may be occurring from agriculture and suggest management alternatives that minimize the problem. The Nitrate Leaching and Economic Analysis Package (NLEAP) model was applied to estimate regional NO3-N leaching in eastern Colorado. Results show that...
Hydrologic modification to improve habitat in riverine lakes: Management objectives, experimental approach, and initial conditions
Barry L. Johnson, John W. Barko, Yuri Gerasimov, William F. James, Alexander Litvinov, Teresa J. Naimo, James G. Wiener, Robert F. Gaugush, James T. Rogala, Sara J. Rogers
R.A. Schoettger, editor(s)
1996, Book chapter, Problems of Aquatic Toxicology, Biotesting, and Water Quality Management
The Finger Lakes habitat-rehabilitation project is intended to improve physical and chemical conditions for fish in six connected back water lakes in Navigation Pool 5 of the upper Missouri River. The primary management objective is to improve water temperature, dissolved oxygen concentration and current velocity during winter for bluegills, Lepomis...
