Use of D-C resistivity to map saline ground water
Christina L. Stamos, Steven K. Predmore, Adel A. R. Zohdy
1992, Book, Irrigation and Drainage: Saving a Threatened Resource - In Search of Solutions, Proceedings of the Irrigation and Drainage Sessions at Water Forum '92
It has been estimated in previous studies that 23 square miles of the Oxnard aquifer, a member of a multi-layered aquifer system beneath the Oxnard plain in Ventura County, California, has been contaminated as a result of seawater intrusion. To investigate this and other potential sources of saline water, a...
D4Z: A new renumbering for iterative solution of ground-water flow and solute-transport equations
K.L. Kipp, T.F. Russell, J.S. Otto
1992, Conference Paper, Finite Elements in Water Resources, Proceedings of the International Conference
D4 zig-zag (D4Z) is a new renumbering scheme for producing a reduced matrix to be solved by an incomplete LU preconditioned, restarted conjugate-gradient iterative solver. By renumbering alternate diagonals in a zig-zag fashion, a very low sensitivity of convergence rate to renumbering direction is obtained. For two demonstration problems involving...
Large lake basins of the southern High Plains: Ground-water control of their origin?
W.W. Wood, W. E. Sanford, C.C. Reeves Jr.
1992, Geology (20) 535-538
The origin of the ∼40-50 topographically large lake basins on the southern High Plains of Texas and New Mexico has been an enigma. Previous workers have considered deflation or evaporite dissolution at depth and subsequent collapse as the most probable mechanisms. However, the eolian hypotheses have been unable to provide...
Seasonal changes in the spatial distribution of phytoplankton in small, temperate-zone lakes
J. E. Cloern, A.E. Alpine, B.E. Cole, T. Heller
1992, Journal of Plankton Research (14) 1017-1024
Seasonal sampling across two small lakes shows that phytoplankton patchiness is greatly enhanced during winter ice-cover relative to the open-water seasons of exposure to wind stress and rapid turbulent mixing....
Geology of the Eel River basin and adjacent region: Implications for late Cenozoic tectonics of the southern Cascadia subduction zone and Mendocino triple junction
S. H. Clarke Jr.
1992, American Association of Petroleum Geologists Bulletin (76) 199-224
Two upper Cenozoic depositional sequences of principally marine strata about 4000m thick overlie accreted basement terranes of the Central and Coastal belts of the Franciscan Complex in the onshore-offshore Eel River basin of northwestern California. The older depositional sequence is early to middle Miocene in age and represents slope basin...
3H and 14C as tracers of ground-water recharge
John A. Izbicki, Robert L. Michel, Peter Martin
1992, Conference Paper, Irrigation and Drainage: Saving a Threatened Resource - In Search of Solutions, Proceedings of the Irrigation and Drainage Sessions at Water Forum '92
Surface spreading of water from the Santa Clara River is used to recharge aquifers underlying the Oxnard Plain. These aquifers are divided into an upper system about 400 feet thick, and a lower system more than 1,000 feet thick. In previous studies, it has been reported that surface spreading recharged...
The extent of temporal smearing in surface-temperature histories derived from borehole temperature measurements
Gary D. Clow
1992, Global and Planetary Change (6) 81-86
The ability of borehole temperature data to resolve past climatic events is investigated using Backus-Gilbert inversion methods. Two experimental approaches are considered: (1) the data consist of a single borehole temperature profile, and (2) the data consist of climatically-induced temperature transients measured within a borehole during a monitoring experiment. The...
Two-dimensional circulation modeling of the Pamlico River estuary, North Carolina
G. L. Giese, Jerad Bales
1992, Conference Paper
A two dimensional, vertically averaged, unsteady flow model was applied to a 50- kilometer reach of the Pamlico River estuary, North Carolina. The model computational grid, which consists of about 16,000 square cells, each 200 meters on a side, was developed from more than one million depth soundings. Information from...
Thermodynamics and kinetics of reactions involving vanadium in natural systems: Accumulation of vanadium in sedimentary rocks
R. B. Wanty, M. B. Goldhaber
1992, Geochimica et Cosmochimica Acta (56) 1471-1483
A critical review of thermodynamic data for aqueous and solid V species is presented to evaluate dissolution, transport, and precipitation of V under natural conditions. Emphasis is given to results of experimental studies of V chemistry, especially those for which the experimental conditions are near those found in nature. Where...
Organic control on shoreface stacking patterns: bogged down in the mire
P.J. McCabe, K.W. Shanley
1992, Geology (20) 741-744
In ever-wet climates, raised mires that are elevated several metres above flood levels can cover significant portions of coastal plains. Because peat accumulation may keep pace with moderate rates of base-level rise, the development of raised mires may reduced the areal extent of...
The San Andreas Fault System, California, USA
R.D. Brown, R. E. Wallace, D.P. Hill
1992, Annales Tectonicae (6) 261-284
Geologists, seismologists, and geophysicists have intensively studied the San Andreas fault system for the past 20 to 30 years. Their goals were to learn more about damaging earthquakes, the behavior of major stirke-slip faults, and methods of reducing earthquake hazards in populated areas. Field geologic investigations, seismic networks, post-earthquake studies,...
Fault stability under conditions of variable normal stress
James H. Dieterich, Mark F. Linker
1992, Geophysical Research Letters (19) 1691-1694
The stability of fault slip under conditions of varying normal stress is modeled as a spring and slider system with rate- and state-dependent friction. Coupling of normal stress to shear stress is achieved by inclining the spring at an angle, ø, to the sliding surface. Linear...
Pesticides in Iowa precipitation
B.K. Nations, G.R. Hallberg
1992, Journal of Environmental Quality (21) 486-492
Rainfall was sampled for pesticides to assess their occurrence in precipitation and potential impacts on water resources. Three areas in Iowa were sampled; two localities were in rural settings, and a third in an urban area. Fourteen pesticides, including ten herbicides and four insecticides, were detected...
Use of weather types to disaggregate general circulation model predictions
L.E. Hay, G. J. McCabe Jr., D.M. Wolock, M. A. Ayers
1992, Journal of Geophysical Research (97) 2781-2790
General circulation models (GCMs) simulate climatic conditions with a grid cell resolution on the order of 100,000 km2. This resolution is inadequate to assess the effects of climatic change on water resources at a regional scale. A method has been developed that uses weather-type analysis as...
A glacier peak and Mount Saint Helens J volcanic ash couplet and the timing of deglaciation in the Colville Valley area, Washington
P. E. Carrara, D.A. Trimble
1992, Canadian Journal of Earth Sciences (29) 2397-2405
A Late Pleistocene volcanic ash couplet consisting of a Glacier Peak ash layer and an underlying Mount Saint Helens J ash layer has been identified at three sites in the Colville Valley area of northeastern Washington. This ash couplet has been reported as far east as northwestern Montana and therefore...
An unusual occurrence of arsenic-bearing pyrite in the Upper Freeport coal bed, West-Central Pennsylvania
L.F. Ruppert, J.A. Minkin, J. J. McGee, C. B. Cecil
1992, Energy & Fuels (6) 120-125
Scanning electron microscopy and electron microprobe analysis were used to identify a rare type of As-bearing pyrite in selected specific gravity separates from the Pennsylvanian age Upper Freeport coal bed, west-central Pennsylvania. Arsenic was detected mainly in cell-wall replacement pyrite where concentrations ranged from nondetectable to 1.9 wt %. Although...
Thermal springs in Lake Baikal
Wayne C. Shanks III, E. Callender
1992, Geology (20) 495-497
Pore waters extracted from sediment cores were analyzed for their oxygen and hydrogen isotopic compositions and major ion chemistry to determine the source of water from a vent area for diffuse lake-bottom thermal springs or seeps in Frolikha Bay, northeastern Lake Baikal. The...
40Ar/39Ar dating of Quaternary feldspar: Examples from the Taupo Volcanic Zone, New Zealand
M. S. Pringle, M. McWilliams, Bruce F. Houghton, M. A. Lanphere, C. J. N. Wilson
1992, Geology (20) 531-534
Using a continuous laser and resistance furnace, we have measured ages on Quaternary plagioclase with an absolute precision of about ±30 ka and on Quaternary sanidine with a relative precision of better than 1%. Such precision was achieved by using low-temperature heating steps to remove much of the nonradiogenic argon...
Subsidence of Surtsey volcano, 1967-1991
J.G. Moore, S. Jakobsson, J. Holmjarn
1992, Bulletin of Volcanology (55) 17-24
The Surtsey marine volcano was built on the southern insular shelf of Iceland, along the seaward extension of the east volcanic zone, during episodic explosive and effusive activity from 1963 to 1967. A 1600-m-long, east-west line of 42 bench marks was established across the island shortly after volcanic activity stopped....
Remote sensing of water clarity and suspended sediments in coastal waters
R. P. Stumpf
1992, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
Processing of data for estimation of suspended sediment concentrations and water clarity in turbid coastal water requires three components: (1) correction of raw data to water reflectance; (2) establishment of appropriate general models relating reflectance characteristics to materials in the water; and (3) determination of the coefficients of the models...
Trophic interactions and direct physical effects control phytoplankton biomass and production in an estuary
A.E. Alpine, J. E. Cloern
1992, Limnology and Oceanography (37) 946-955
San Francisco Bay has recently been invaded by the suspension-feeding clam Potamocorbula amurensis. Previous work has shown that phytoplankton biomass in the upper estuary is low (2-3 mg Chl a m-3) during seasonal periods of high river flow and short residence time and it is usually high (peak >30 mg...
Sulfate retention and release in soils at Panola Mountain, Georgia
J. B. Shanley
1992, Soil Science (153) 499-508
Inorganic sulfate pools, sulfate sorption characteristics, and Fe and Al fractions were determined on soils at Panola Mountain, a 41-ha forested watershed in the Georgia Piedmont. Sulfate sorption properties of these soils fall along a continuum between two end members. The "low-adsorbing' end member comprises shallow soils (0-10 cm), with...
Incorporation and redistribution of locally derived lithic fragments within a pyroclastic flow
D.C. Buesch
1992, Geological Society of America Bulletin (104) 1193-1207
The lower Miocene Peach Springs Tuff exposed in the Newberry Mountains, California, was deposited within a paleovalley trending S65°W. Exposures within the paleovalley contain lithic breccia intercalated with ash-rich ignimbrite. The clast assemblage of the lithic breccias matches the rock types of the paleovalley walls, and therefore the clasts were...
Comparison of spatial variability in visible and near-infrared spectral images
P.S. Chavez Jr.
1992, Photogrammetric Engineering and Remote Sensing (58) 957-964
The visible and near-infrared bands of the Landsat Thematic Mapper (TM) and the Satellite Pour l'Observation de la Terre (SPOT) were analyzed to determine which band contained more spatial variability. It is important for applications that require spatial information, such as those dealing with mapping linear features and automatic image-to-image...
Laboratory investigations on the role of sediment surface and ground water chemistry in transport of bacteria through a contaminated Sandy Aquifer
M. A. Scholl, R.W. Harvey
1992, Environmental Science & Technology (26) 1410-1417
No abstract available. ...
