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Conference Papers

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A spectral reflectance study (0.4-2.5 μm) of selected playa evaporite mineral deposits and related geochemical processes A spectral reflectance study (0.4-2.5 μm) of selected playa evaporite mineral deposits and related geochemical processes

Playa evaporite mineral deposits show major compositional variations related to differences in lithology, hydrology, and groundwater geochemistry. The use of visible and near-infrared (VNIR) spectral reflectance measurements as a technique for investigating the mineralogy of playa efflorescent crusts is examined. Samples of efflorescent crust were collected from 4 playa: Bristol Dry Lake...
Authors
James K. Crowley

Acoustic Doppler discharge-measurement system Acoustic Doppler discharge-measurement system

A discharge-measurement system that uses a vessel-mounted acoustic Doppler current profiler has been developed and tested by the U.S. Geological Survey. Discharge measurements using the system require a fraction of the time needed for conventional current-meter discharge measurements and do not require shore-based navigational aids or tag lines for positioning the vessel.
Authors
Michael R. Simpson, Richard N. Oltmann

Arsenopyrite in the bank deposits of the Whitewood Creek-Belle Fourche-Cheyenne River-Lake Oahe system, South Dakota, U.S.A. Arsenopyrite in the bank deposits of the Whitewood Creek-Belle Fourche-Cheyenne River-Lake Oahe system, South Dakota, U.S.A.

Mining, milling, and processing wastes containing quantities of arsenopyrite were produced around Lead, South Dokata, from 1875 to 1977. Much of this material was discharged into Whitewood Creek, and from there portions of the waste were transported to the Belle Fourche River, thence to the Cheyenne River, and finally to the Missouri River. In 1958, the Missouri River was dammed at...
Authors
A. J. Horowitz, K. A. Elrick, R.B. Cook

Channel-changing processes on the Santa Cruz River, Pima County, Arizona, 1936-86 Channel-changing processes on the Santa Cruz River, Pima County, Arizona, 1936-86

Lateral channel change on the mainly ephemeral Santa Cruz River, Pima County, Arizona, causes damage and has spawned costly efforts to control bank erosion. Aerial photographs, historical data, and field observations are used to document the history of channel change since 1936. Variability in the nature and degree of channel change over time and space is shown. Three major channel...
Authors
John T.C. Parker

Characterization of carbon in sediment-hosted disseminated gold deposits, north central Nevada Characterization of carbon in sediment-hosted disseminated gold deposits, north central Nevada

The gray, dark gray and black colors of the sediments and the presence of pyrite in the Carlin, Jerritt Canyon, Horse Canyon, Betze, and Gold Acres sediment-hosted disseminated gold (SHDG) deposits indicate that these rocks are not oxidized with respect to carbon and iron sulfide. The organic matter in the host rocks of SHDG deposits in north-central Nevada is cryptocrystalline graphite...
Authors
Joel Leventhal, Albert Hofstra

Computational open-channel hydraulics for movable-bed problems Computational open-channel hydraulics for movable-bed problems

As a major branch of computational hydraulics, notable advances have been made in numerical modeling of unsteady open-channel flow since the beginning of the computer age. According to the broader definition and scope of 'computational hydraulics,' the basic concepts and technology of modeling unsteady open-channel flow have been systematically studied previously. As a natural extension
Authors
Chintu Lai

Conductivity and transit time estimates of a soil liner Conductivity and transit time estimates of a soil liner

A field-scale soil linear was built to assess the feasibilty of constructing a liner to meet the saturated hydraulic conductivity requirement of the U.S. EPA (i.e., less than 1 ?? 10-7 cm/s), and to determine the breakthrough and transit times of water and tracers through the liner. The liner, 8 ?? 15 ?? 0.9 m, was constructed in 15-cm compacted lifts using a 20,037-kg pad-foot compactor...
Authors
I.G. Krapac, K. Cartwright, S.V. Panno, B.R. Hensel, K.H. Rehfeldt, B.L. Herzog
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