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We present the results of a Trans‐Alaska Crustal Transect (TACT) investigation of the upper 2–5 km of the eastern Alaska Range in the vicinity of the Denali fault based on seismic reflection/refraction data, laboratory measurements of rock velocities, and structural mapping. The Denali fault is a major dextral slip structure...

An intensive in situ sampling program near Marco Island, Florida during 19–23 October 1988 collected information on mangrove type, maximum canopy height, and percent canopy closure. These data were correlated with selected vegetation index information derived from analysis of SPOT multispectral (XS) data obtained on 21 October 1988. The Normalized...

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This paper focuses on the association between concentrations of iron disulfide (FeS 2 ) minerals in the shallow subsurface and underlying hydrocarbon accumulations. Such FeS 2 concentrations are the result of migration of either H 2 S or organic constituents from the underlying hydrocarbons. The H 2 S from reservoirs is produced inorganically from sulfate in the reservoir...

A three-dimensional interpretation of the basins of Nevada was developed based on statewide data bases of digital-gravity, magnetic, geologic, well, and topographic information. An iterative technique was applied to isostatic residual gravity anomalies in Nevada in order to define the location and shape of pre-Tertiary basement and to produce a...

QuickMAP, a prototype desktop mapping system (DMS), uses easy to learn, simple to use windows, menus, and dialogues to provide support in natural resources decision-making....

Seismic-velocity models for Archean and Proterozoic provinces throughout the world are analyzed. The thickness of the crust in Archean provinces is generally found to be about 35 km (except at collisional boundaries), whereas Proterozoic crust has a significantly greater thickness of about 45 km and has a...

Knowledge of carbon dioxide concentration in desert soils is required in theoretical models of the development of pedogenic and ground-water calcium carbonate. Most studies have concentrated on medium- to fine-textured soils in temperate to humid environments. Very little data exist for CO2 concentrations in stony, coarse-textured deposits such as those making...

ime courses for ingest~on, retention and release via feces of microbial food was investigatedusing 2 b~valves w~th d~fferent feeding strategies, Potamocorbula amurensis and Macomabalthica. The results showed 2 pathways for the uptake of food material in these clams. The first isrepresented by an initlal label pulse in the feces....

Centrifugal force is an alternative to large pressure gradients for the measurement of low values of saturated hydraulic conductivity (Ksat). With a head of water above a porous medium in a centrifuge bucket, both constant-head and falling-head measurements are practical at forces up to at least 1800 times normal gravity....

The use of feathers has been proposed as a noninvasive tissue for biomonitoring metal levels in birds and their ecosystems. We examined cadmium and lead levels in black and white contour feathers from common (Sterna hirundo) and sooty (S. fuscata) terns, and black skimmers (Rynchops niger) to determine if there were significant differences...

No abstract available....

An early to mid-Holocene warm period with greater than present-day monsoonal circulation is indicated by evidence in the northern San Juan Mountains of southwestern Colorado. Fifty radiocarbon ages of coniferous wood fragments, and several other radiocarbon ages of willow fragments, woody peat, and organic sediment associated with conifer remains, recovered...

The persistence of rotenone was compared between a cement-lined pond (0.04 hectare) and an earthen-bottom pond (0.02 hectare) treated with 5 μL Noxfish/L (250 μg rotenone/L) during spring, summer, and fall. Water temperatures on the days of treatment in each season were 8, 22, and 15°C, respectively. Both ponds were...

The Paoli silver-copper deposit is located in south-central Oklahoma, 56 km south-southeast from Norman, Oklahoma. It was mined for high-grade silver-copper near the beginning of this century, and intensive exploratory drilling during the early 1970's delineated unmined portions of the deposit. A collaborative study between the U.S.G.S., the Kansas Geological...

Five sedimentary-rock-hosted disseminated gold deposits have been discovered since 1980 in southwestern Guizhou Province (PRC). Submicron-sized gold is disseminated in silty carbonate and carbonaceous shale host rocks of Permian and Triassic age. Arsenic, antimony, mercury, and thallium accompany the gold. Associated hydrothermal alteration resulted in decarbonatization of limestone, silicification, and...

Acceleration response records obtained during the October 1, 1987 Whittier‐Narrows earthquake (Ms=5.6)">(Ms=5.6) from the 32‐story, vertically...

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In order to investigate the effects of human activities on relationships within foraging guilds, we examined inacanus dynamics of eagles, crows, and gulls scavenging on spawned salmon in the Pacific Northwest. We examined several hypotheses that postulate the asymmetric foraging relationships of the three guild members and that reveal the...

Approximately 160 Ma old basaltic lavas obtained from ODP Site 801 in the Pigafetta Basin represent the first Jurassic oceanic crust recovered in the Pacific Ocean and the oldest in situ oceanic crust discovered anywhere. The basement consists of an upper alkali olivine basalt sequence and a lower tholeiitic sequence separated by...

A large-scale natural gradient tracer test was conducted to examine the transport of reactive and nonreactive tracers in a sand and gravel aquifer on Cape Cod, Massachusetts. As part of this test the transport of bromide, a nonreactive tracer, was monitored for about 280 m and quantified using spatial moments....

A large-scale natural gradient tracer experiment was conducted on Cape Cod, Massachusetts, to examine the transport and dispersion of solutes in a sand and gravel aquifer. The nonreactive tracer, bromide, and the reactive tracers, lithium and molybdate, were injected as a pulse in July 1985 and monitored in three dimensions...

Tests of a one-dimensional sampling design methodology on measurements of bromide concentration collected during the natural gradient tracer test conducted by the U.S. Geological Survey on Cape Cod, Massachusetts, demonstrate its efficacy for field studies of solute transport in groundwater and the utility of one-dimensional analysis. The methodology was applied...