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Isotopic studies of the Rb-Sr and U-Th-Pb systems in whole-rock samples and the U-Pb systematics for zircons document the existence of two late Arehean intrusive events in the Wind River Range. All of the systems examined indicate an age of ∼2,630 ± 20...

The Ascutney Mountain igneous complex in eastern Vermont, USA, is composed of three principal units with compositions ranging from gabbro to granite. Sr and O isotopic and major element relationships for mafic rocks, granites, and nearby gneissic and schistose country rock have been investigated in order to describe the petrogenesis...

The discharge of effluents containing creosote and pentachlorophenol into two unlined surface impoundments at a wood-treatment facility in Pensacola, Florida, resulted in contamination of the underlying sand and gravel aquifer. These wastes contained significant amounts of chlorinated dioxins, such as isomers of hexa- and heptachlorodibenzo-p-dioxins and octachlorodibenzo-p-dioxin, probably derived from...

Epithermal Ag-Au vein and disseminated deposits in the Yankee Fork district are hosted in altered volcanic rocks having low delta 18 O values, low magnetic susceptibilities, low remanent magnetizations, and relatively high densities. These isotopic and physical quantities provide sensitive indices of rock alteration that can be contoured over areas that are...

No abstract available....

Microprocessor technology has permitted the development of a General Earthquake-Observation System (GEOS) useful for most seismic applications. Central-processing-unit control via robust software of system functions that are isolated on hardware modules permits field adaptability of the system to a wide variety of active and passive seismic experiments and straightforward modification...

The upper Cook Inlet region of southcentral Alaska would be significantly impacted by a major tephrafall, owing to a widespread population and heavily travelled transportation corridors. To evaluate the likelihood of such an occurrence, the tephra deposits of the region have been inventoried. Approximately 90 deposits of Holocene age are...

Public statements about volcanic activity at Mount St. Helens include factual statements, forecasts, and predictions. A factual statement describes current conditions but does not anticipate future events. A forecast is a comparatively imprecise statement of the time, place, and nature of expected activity. A prediction is a comparatively precise statement of the time, place, and ideally,...

Errors in complex conceptual precipitation-runoff models may be analyzed by placing them into a statistical framework. This amounts to treating the errors as random variables and defining the probabilistic structure of the errors. By using such a framework, a large array of techniques, many of which have been presented in...

In the interpretation of induced polarization data, it is commonly assumed that metallic mineral polarization dominantly or solely causes the observed response. However, at low frequencies, there is a variety of active chemical processes which involve the movement or transfer of electrical charge. Measurements of electrical properties at low frequencies...

National Water Information System (NWIS) has been designed as an interactive, distributed data system. It will integrate the existing, diverse data-processing systems into a common system. It will also provide easier, more flexible use as well as more convenient access and expanded computing, dissemination, and data-analysis capabilities. The NWIS is...

The analytical solutions developed in the first paper can be used to interpret the results of cross-hole tests conducted in anisotropic porous or fractured media. In the particular case where the injection and monitoring intervals are short relative to the distance between them, the test results can be analyzed graphically....

The dry valleys of southern Victoria Land, constituting the largest ice-free expanse in the Antarctic, contain numerous lakes whose perennial ice cover is the cause of some unique physical and biological properties 1-3. Although the depth, temperature and salinity of the liquid water varies considerably from lake to lake, the...

It has been shown that the apparent enhancement of divalent metal ion binding to polyions such as polystyrenesulfonate (PSS) and dextran sulfate (DS) by decreasing the ionic strength of these mixed counterion systems (M2+, M+, X-, polyion) can be anticipated with the Donnan-based model developed by one of us (J.A.M.)....

Evidence for previous periods of hydrothermal activity in Long Valley caldera exists in the form of extensive deposits of hydrothermal alteration products at several locations within the caldera and saline deposits in Searles Lake which contain mineral assemblages contributed by hot spring discharge from Long Valley. Hydrothermal activity was more...

Digital image transformation and rectification can be described in three categories: (1) digital rectification of spacecraft pictures on workable stereoplotters; (2) digital correction of radar image geometry; and (3) digital reconstruction of shaded relief maps and perspective views including stereograms. Digital rectification can make high-oblique pictures workable on stereoplotters that...

The tectonic setting comprising the West Shasta mining district has often been compared with that of primitive island arcs. Concentrations of uranium, thorium, and lead and lead isotope compositions were determined for Devonian ores and rocks of the West Shasta district, eastern Klamath Mountains, California, to help evaluate the tectonic...

The magnetotelluric geophysical method has been used effectively as a hydrocarbon exploration tool in the intracratonic Parana basin of South America. The Parana basin has an area of about 1,200,000 km2 (463,000 mi2), extending over portions of Brazil, Paraguay, Uruguay, Argentina, and Bolivia. The Paleozoic marine sedimentary rocks in the Parana...

Geologic relations indicate that silica phases transformed in the Monterey Formation in two zones that persist over a narrow depth/temperature range and do not stratigraphically overlap. The wide and overlapping range of reported temperatures of these transformations is mainly a result of the many uncertainties inherent in the different methods...

Chelate-extractable iron and manganese concentrations in soils over and around the Bell Creek oil field suggest that compared to low average background values, there are moderate amounts of these elements directly over the production area and higher concentrations distributed in an...

The telecommunications industry is undergoing tremendous change due to the court ordered breakup of the monopoly once enjoyed by American Telephone & Telegraph (AT&T). This action has resulted in a plethora of new services and products in all of the communications fields, including traditional voice and data. The new products...

Seismic reflection profiles and long- and medium-range sidescan sonar were used to investigate a salt diapir complex and area of slope instability near the base of the Continental Slope off North Carolina. Within the area of investigation three diapirs are bounded on their upslope side by a scarp 60 m...

A model for the optimal allocation of water resources was developed for a multiaquifer groundwater and surface water system near Livermore, California. The complex groundwater system was analyzed using a transient, quasi-three-dimensional model that considers the nonlinear behavior of the unconfined aquifer. The surface water system consists of a reservoir...

Raman spectra of crystalline polymorphs of a number of tectosilicate minerals having various sizes of smallest rings of TO4 tetrahedra (T = Si, Al) have been investigated to identify the bands that are sensitive indicators of the smallest rings in the network. The information obtained from the Raman spectra of tectosilicate...

No abstract available....