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Total mercury in a variety of substances is determined rapidly and precisely by direct sample combustion, collection of released mercury by amalgamation, and photometric measurement of mercury volatilized from the heated amalgam. Up to 0.2 g fish tissue is heated in a stream of O2 (1.2 L/min) for 3.5 min...

Dredge hauls of fresh submarine basalt collected from the axis of the Reykjanes Ridge (Mid-Atlantic Ridge) south of Iceland were taken aboard R/ V TRIDENT in 1967 and 1971. The samples show systematic changes as the water depth of collection (and eruption) decreases: radially elongate vesicles and concentric zones of vesicles appear...

The amount of water and sulfur in pumice erupted during periods of vigorous activity during the 1969-71 Mauna Ulu eruption varied inversely with fountain height because of degassing during the fountaining. The pumice lost about 0.05 wt percent water and 0.003 wt percent sulfur during fountaining to heights of 400-540 m. Analyses suggest that the...

The phase relations of three basalts, the Picture Gorge tholeiite, the 1921 Kilauea olivine tholeiite, and the 1801 Hualalai alkali basalt, were studied at 5 kb water pressure, 680–1000°C, at the oxygen fugacities of the quartz-fayalite-magnetite (QFM) and hematite-magnetite (HM) buffers.In the range 680–850 °C, the crystalline assemblage...

Fayette County is in central West Virginia. Rocks exposed at the surface are about 3,200 feet thick and comprise the Pocahontas, New River, Kanawha, and Allegheny Formations of Pennsylvanian age. The stratigraphic relations and distribution of coal in these formations were studied by the U.S. Geological Survey in connection with a low-sulfur coal program...

The first 4 months of Mariner 9 photography of the south polar region are discussed. Three major geological units have been recognized, separated by erosional unconformities. From oldest to youngest they are: cratered terrain, pitted plains, and laminated terrain. The latter unit is unique in occurrence to the polar region,...

An experiment centering around a mass spectrometer is described, which is aimed at the identification of organic substances present in the top 10 cm of the surface of Mars and an analysis of the atmosphere for major and minor constituents as well as isotopic abundances. In addition, an indication of...

The geochemist can contribute much information of value toward assessing the effect of environment, including inorganic pollution, on health....

A review of the literature indicates that a reasonable estimate of the composition of the earth's core is iron with Ni0–5, Si10–25 (wt.%). Thermodynamic calculations and comparison of chondritic with terrestrial abundances indicate that 1 wt.% each of Mn, P, and Cr might also be present. A core of this composition...

Deep sea pillow basalts dredged from the ocean floor show that vesicularity changes with composition as well as with depth. Alkalic basalts are more vesicular than tholeiitic basalts erupted at the same depth. The vesicularity data, when related to experimentally determined solubility of water in basalt, indicate that K-poor oceanic...

The Ar36 content of densely welded glasses from ash-flow units provides a means by which the amount of air entrapped and subsequently resorbed by the glasses during compaction and welding may be calculated. The amount of air measured in glasses from nine upper Tertiary ash-flow sheets...

Under favorable conditions the chemistry of hot springs may give reliable indications of subsurface temperatures and circulation patterns. These chemical indicators can be classified by the type of process involved:IndicatorDominant ProcessThe silica...

Ocean-floor dredging and submarine photography in the Revillagigedo region off the west coast of Mexico reveal that the dominant exposed rock of the submarine part of the large island-forming volcanoes (Roca Partida and San Benedicto) is a uniform alkali pillow basalt; more siliceous rocks are exposed on the upper, subaerial...

The genesis of granitic igneous pegmatites is here considered in terms of a model conceived from results of field and laboratory studies and subsequently tested by means of experimental investigations. This model emphasizes the roles of water (and/or other relatively volatile substances), both as a dissolved constituent in granitic magmas...

The Cloudy Pass batholith, one of several small epizonal Tertiary batholiths in the Northern Cascade Mountains, discordantly intrudes metamorphic rocks of pre-Late Cretaceous age. The batholith is remarkable for its chilled borders, associated porphyry plugs, and intrusive breccias. The main body of the batholith consists largely of labradorite granodiorite.Part of...

The meteorite classes of Prior and Mason are assigned to three proposed genetic groups on the basis of a combination of compositional, mineralogical, and elemental characteristics: l) the calcium-poor, volatile-rich carbonaceous chondrites and achondrites; 2) the calcium-poor, volatile-poor chondrites (enstatite, bronzite, hypersthene, and pigeonite), achondrites (enstatite, hypersthene, and pigeonite), stonyirons...

The electron probe X-ray microanalyzer has been used to determine the compositional variability of the groundmass minerals and glass in 10 specimens from a complete 225-foot section of the prehistoric tholeiitic lava lake of Makaopuhi Crater, Hawaii. The order of beginning of crystallization was: (1) chromite, (2) olivine, (3) augite,...

Most of the organic matter in naturally colored surface waters consists of a mixture of carboxylic acids or salts of these acids. Many of the acids color the water yellow to brown; however, not all of the acids are colored. These acids range from simple to complex, but predominantly they...

A modified Morey bomb was designed which contains a removable nichromecased 3.5-ml platinium crucible. This bomb is particularly useful for decompositions of refractory samples for micro- and semimicro-analysis. Temperatures of 400–450° and pressures estimated as great as 6000 p.s.i. were maintained in the bomb for...

A well drilled for geothermal power near Salton Sea in Imperial Valley, Calif., is 5,232 feet deep; it is the deepest well in the world (1962) in a high-temperature hot spring area. In the lower half of the hole temperatures are too high to measure with available equipment, but are...

The total vapor pressure of Philippine tektite melts of approximately 70 per cent silica has been determined at temperatures ranging from 1500 to 2100°C. This pressure is 190 ± 40 mm Hg at 1500°C, 450 ± 50 mm at 1800°C and 850 ± 70 mm at 2100° C. Determinations were...

Oxidation of the sulfur amino acids by autoxidizing lipids was studied in a model system consisting of an amino acid dispersed in cold-pressed, molecularly distilled menhaden oil (20–80% w/w). Under all conditions investigated, cysteine was oxidized completely to cystine. Preliminary results suggest that at 110°C the oxidation follows first-order kinetics...

Assuming that many hydrothermal ore deposits are formed from emanations given off from a magma at depth while it cools through the interval in which latent heat of crystallization is generated, it is shown that this cooling interval for magmatic bodies of moderate size must be measured in tens or hundreds of...

Assuming that many hydrothermal ore deposits are formed from emanations given off from a magma at depth while it cools through the interval in which latent heat of crystallization is generated, it is shown that this cooling interval for magmatic bodies of moderate size must be measured in tens or hundreds of...

Pegmatite occurs widely in Nevada and northwestern Arizona, but little mining has been done for such pegmatite minerals as mica, feldspar, beryl, and lepidolite. Reconnaissance for beryl-bearing pegmatite in Nevada and in part of Mohave County, Ariz., and detailed studies in the Dawley Canyon area, Elko County, Nev., have shown...