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Field associations (voluminous ash flow deposits, rhyolitic stocks and dykes, ring complexes), evidence of repeated influxes of mafic magma, and thermal constraints indicate that many high-level silicic plutons (magma chambers) acted as open systems for considerable parts of their history. The long thermal lifetime, as well as other evidence from...

The Arctic volcanogenic massive sulfide prospect, located in the Ambler mineral district of northwestern Alaska, includes three types of hydrothermally altered rocks overlying, underlying, and interlayered with semimassive sulfide mineralization. Hydrothermal alteration of wall rocks and deposition of sulfide and gangue minerals were contemporaneous with Late Devonian or Early Mississippian...

Allan Hills 85085 is a unique chondrite with affinities to the Al Rais-Renazzo clan of carbonaceous chondrites. Its constituents are less than 50 μm in mean size. Chondrules and microchondrules of all textures are present; nonporphyritic chondrules are unusually abundant. The mean compositions of porphyritic, nonporphyritic and barred olivine chondrules...

The Henderson porphyry molybdenum deposit was formed by the superposition of coupled alteration and mineralization events, of varying intensity and size, that were associated with each of at least 11 intrusions. Deposition of molybdenite was accompanied by time-equivalent silicic and potassic alteration. High-temperature alteration and mineralization are spatially and temporally...

Volcanic rocks of the Latir volcanic field evolved in an open system by crystal fractionation, magma mixing, and crustal assimilation. Early high-SiO2 rhyolites (28.5 Ma) fractionated from intermediate compositionmagmas that did not reach the surface. Most precaldera lavas have intermediate-compositions, from olivine basaltic-andesite (53% SiO2) to quartz latite (67% SiO2)....

A series of decomposed and coalified gymnosperm woods was examined by conventional solid-state 13C nuclear magnetic resonance (NMR) and by dipolar-dephasing NMR techniques. The results of these NMR studies for a histologically related series of samples provide clues as to the nature of codification reactions that lead to the defunctionalization...

The fate of acetone in water was investigated in an outdoor model stream located in southern Mississippi, U.S.A. Acetone was injected continuously for 32 days resulting in small milligram-perliter concentrations in the stream. Rhodamine-WT dye was injected at the beginning and at the end of the study to determine the...

New reflectance spectra have been obtained for both the leading and trailing sides of Europa, using the Cooled Grating Array Spectrometer (CGAS) of the NASA Infrared Telescope Facility (IRTF). The spectra are of higher precision than any yet obtained. Spectra of Europa's trailing side (central meridian longitude ≈300°) obtained in...

Fluid sampled from granitic rock near the 2 km depth in the DOSECC Cajon Pass well contained He, H2, CH4, C2H6, and C2H4 in concentrations much greater than in air-saturated water. The dissolved helium, which ranged in concentration from 0.6 to 0.8 µmole/kg-fluid, was almost entirely radiogenic...

The loss of professional experience and expertise in the domain of the earth sciences may prove to be one of the most serious outcomes of the boom-and-bust cyclic nature of the volatile energy and mining industries. Promising new applications of powerful computer systems, known as 'expert systems' or 'knowledge-based systems',...

The climactic eruption of Mount Mazama has long been recognized as a classic example of rapid eruption of a substantial fraction of a zoned magma body. Increased knowledge of eruptive history and new chemical analyses of ∼350 wholerock and glass samples of the climactic ejecta, preclimactic rhyodacite flows and...

Three domestic wells that withdraw groundwater from an alluvium-filled trough cut into granite were found to be contaminated with the organic solvents tetrachloroethene, trichloroethene, 1,1,1-trichloroethane, and 1 ,2-trans-dichloroethene. The suspected source of contamination is a nearby septic-tank sludge disposal area. There is concern that the affected aquifer is tributary to...

Hydrogeologic data was collected for a study of the Saco River valley glacial aquifer. The study area extends along the Saco River from Bartlett, New Hampshire to Fryeburg, Maine. The study was done in cooperation with the Maine Geological Survey (Department of Conservation), the New Hampshire Water Supply and Pollution...

Rapid urban development in the Austin metropolitan area, Texas, is causing concern about increasing peak discharges from storm runoff and the degradation of the quality of water in receiving streams, lakes, and aquifers. In an attempt to decrease peak discharges and improve water quality, runoff controls are being required in...

This report presents geohydrologic and water quality data from the northern part of the Town of Oyster Bay, in the north-shore area of Long Island. The groundwater reservoir underlying the area consists of clay, silt, sand, and gravel layers that form six geohydrologic units; from bottom to top: the Lloyd...

The quality of most ground and surface water within and adjacent to the lower Puyallup River valley is suitable for most typical uses; however, some degradation of shallow groundwater quality has occurred. High concentrations of iron and manganese were found in groundwater, sampled at depths of < 40 ft, from...

INTRODUCTION Ground water is the principal source of drinking water for about 850,000 people in Puerto Rico (National Water Summary, 1985). Ground-water withdrawals for public supply, agricultural, and industrial water uses in Puerto Rico are about 250 million gallons per day (Mgal/d) (Torres-Sierra and Aviles, 1985). The development of the most...

Identification of the presence of volatile organic compounds in liquid-waste lagoons in New Mexico at the Lee Acres landfill, beneath a refinery south of the landfill, and in nearby residential wells has led to an hydrologic investigation of the area. The alluvium underlying an arroyo adjacent to the landfill mostly...

This report reviews the occurrence and distribution of manmade organic compounds in the surface waters of the United States. On the basis of their aqueous solubilities, nonionic organic compounds partition themselves between water, dissolved organic matter, particulate organic matter, and the lipid reservoirs of aquatic organisms. Ionized organic compounds can...

During February to July 1985, water samples were collected from 55 wells in the western San Joaquin Valley, California, for chemical analysis to determine if 20 selected pesticides and 26 volatile organic compounds were present. Twenty-six of the sampled wells are completed in the shallow unconfined regional aquifer and 29...

Groundwater is the principal source of drinking water in central Florida. The most important hydrogeologic unit is the Floridan aquifer system, consisting of fractured limestone and dolomite limestone. Activities of man in areas of recharge to the Floridian aquifer system that may be affecting groundwater quality include: (1) the use...

A water-quality, data-collection network on a 26.2-mile reach of Cedar Creek in west-central Illinois was operated from May through December 1985 and from March through October 1986. The study reach drains a 60.8-square-mile area of predominantly agricultural land. However, the city of Galesburg contributes combined- and storm-sewer discharge to the...

Groundwater contamination by chlorinated volatile organic compounds detected by the Massachusetts Department of Environmental Quality Engineering in 1979 forced the closing of public supply wells G and H in the City of Woburn, MA. The EPA has ranked the wells G and H site on the National Priorities List as...