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At least 865 records · Page 48Linked to original sources
USGS1974

Garrelsite, NaBa3Si2B7O16(OH)4

Garrelsite, NaBa 3 Si 2 B 7 O 16 (OH) 4 , originally described in 1955, has recently been reexamined by Charles Milton and Adolf Pabst and by Subrata Ghose and Horst H. Ulbrich. The latter have reanalyzed the mineral and determined the structure; the powder pattern is indexed on the basis of their 1972 cell constants. These were refined in 1973 to ɑ =14.639 A, b =8.466 A, c =13.438 A, β =114.21°, space group C 2/c. Garrelsite has been found in two drill cores penetrating the Green River Formation (Eocene) at two localities in Uintah County, Utah, and in the borate deposits of the Kramer district, Kern County, Calif. The original description of the morphology has been corrected, and the optical orientation has been redetermined.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Phosphatic zone in the lower part of the Maquoketa Shale in northeastern Iowa

The basal beds of the Maquoketa Shale in northeastern Iowa include a basal silty phosphorite layer that is thickest near Dubuque. In Clayton County, Iowa, the bed averages about 1 foot thick (30 centimeters) and contains 22.5 percent P 2 0 5 . Phosphatic dolomite that is 8 10 feet (2.4 3 meters) thick and occurs higher in the Maquoketa was observed only in Dubuque County. The thickest and most phosphatic rock in the Maquoketa appears to be coextensive with dark-brown shale, which also occurs mainly in Dubuque County. Rare-earth content of the phosphatic rock decreases southeastward across the area, ranging from 2,000 to about 120 parts per million. The thin low-grade phosphorite is typical of the platform-type phosphorite facies and may be' genetically related to the emergence of the Ozark uplift as an island late in the Ordovician period.

Iowa↗
USGS1974

WATEQ, a computer program for calculating chemical equilibria of natural waters

The computer program, WATEQ, calculates the equilibrium distribution of inorganic aqueous species of major and important minor elements in natural waters using the chemical analysis and in situ measurements of temperature, pH, and redox potential. From this model, the states of reaction of the water with solid and gaseous phases are calculated. Thermodynamic stabilities of aqueous species, minerals, and gases have been selected from a careful consideration of all available experimental data. The program is written in PL-1 for IBM 360 computers.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Hydrogeology of Antietam Creek basin

The Antictam Creek basin in the Great Valley of Maryland and Pennsylvania is underlain almost entirely by intensely folded and faulted lower Paleozoic carbonate rocks. The ground-water discharge of the basin is about 85 percent of the total discharge, in contrast with less than 70 percent of the total discharge in two small basins underlain by igneous and mctamorphic rocks in the Maryland Piedmont. Large quantities of ground water are stored in a thick residual mantle, which overlies the carbonate rocks in the valley and adjacent rnetamorphic rocks in mountain areas on the east edge of the basin. Streams that flow off the mountain areas are major sources of recharge to the carbonate-rock aquifers. Several streams lose a large part of their flow within a mile after reaching the carbonate rocks in the valley, and a few flow directly into swallow holes (sinkholes). The low density of perennial streams in the basin is a result of subsurface drainage through solution cavities along joints, faults, and bedding in the carbonate rocks. The major orientations of straight stream reaches along Antietam Creek and the strikes of major joint sets in quarries are nearly coincident, suggesting that the stream network throughout the basin is joint controlled.

Maryland, Pennsylvania↗
USGS1978

Low-cost computer classification of land cover in the Portland area, Oregon, by signature extension techniques

Computer-aided techniques for interpreting multispectral data acquired by Landsat offer economies in the mapping of land cover. Even so, the actual establishment of the statistical classes, or "signatures," is one of the relatively more costly operations involved. Analysts have, therefore, been seeking cost-saving signature extension techniques that would accept training data acquired at one time or place and apply them to another. Signatures may be extended in preprocessing steps or in the classification steps that follow. In the present example, land cover classes were derived by the simplest and most direct form of signature extension: Classes statistically derived from a Landsat scene of the Puget Sound area, Wash., were applied to the adjacent Landsat scene of the Portland area, Oreg., acquired during the next 25 seconds down orbit. Many features can be recognized on the reduced-scale version of the Portland land cover map shown in this report although no statistical assessment of its accuracy is available.

Oregon, Washington↗
USGS1974

Geochemical indicators of subsurface temperature: Part 1, basic assumptions

The chemical and isotopic compositions of hot-spring water and gas are used to estimate subsurface temperatures. The basic assumptions inherent in the methods are seldom stipulated. These assumptions include (1) a temperature-dependent reaction at depth, (2) a supply of the solid phase involved in the reaction to permit saturation of the constituent used for geothermometry, (3) water-rock equilibrium at depth, (4) negligible re-equilibration as the water flows to the surface, and (5) no dilution or mixing of hot and cold water. The first three assumptions are probably good for a few reactions that occur in many places. The last two assumptions probably are not valid for many hot-spring systems; information obtained is therefore for the shallower parts of those systems, or a limiting temperature (generally a minimum) is indicated.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Geochemical indicators of subsurface temperature: Part 2, estimation of temperature and fraction of hot water mixed with cold water

The water in many warm springs with large rates of flow consists of mixtures of hot water that has come from depth and of shallow cold water. Under favorable conditions the original temperature of the hot water and the fraction of the cold water in the mixture can be estimated by using the measured temperature and silica content of the warm spring water and the temperature and silica content of nonthermal water in the region. The method has been applied with apparent success at Yellowstone National Park.

Wyoming↗
USGS1974

Some morphometric properties of experimentally cratered surfaces

The temperature and chemical conditions (pH, gas pressure, and ion activities) in a geothermal aquifer supplying a producing bore can be calculated from the enthalpy of the total fluid (liquid + vapor) produced and chemical analyses of water and steam separated and collected at known pressures. Alternatively, if a single water phase exists in the aquifer, the complete analysis (including gases) of a sample collected from the aquifer by a downhole sampler is sufficient to determine the aquifer chemistry without a measured value of the enthalpy. The assumptions made are that the fluid is produced from a single aquifer and is homogeneous in enthalpy and chemical composition. These calculations of aquifer chemistry involving large amounts of ancillary information and many iterations require computer methods. A computer program in PL-1 to perform these calculations is available from the National Technical Information Service as document PB-219 376.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Tectonic transition zone in the northeastern Caribbean

Seismic reflection data indicate that the Atlantic plate has been underthrust beneath the Caribbean plate east of the Lesser Antilles. The data further reveal that the transition from underthrust to strike-slip plate motion occurs near lat 19.3° N. and long 62° W. in alinement with the Anegada Trough. Oceanic basement and reflectors above basement have not been detected beneath the landward wall of the Puerto Rico Trench west of the transition zone. Southeast of the zone, the horizontal distance over which the reflectors and basement can be traced beneath the landward wall (outer part of the Lesser Antilles rise) systematically increases from a few kilometers in the north to as much as 37 km near lat 16.5° N. If a thrust fault emerges at the landward trench wall, the data suggest that a decollement exists between reflectors above basement and an overlying acoustically transparent zone. Gravity and seismic refraction data indicate a thick accumulation of low-density, low-velocity material beneath the Lesser Antilles rise, possibly sediments scraped off the underthrusting Atlantic plate, although massive slumping might cause a similar low-density configuration. The magmatic history of the Lesser Antilles arc suggests two periods of underthrusting, one in the Mesozoic or early Cenozoic and a second in the late Cenozoic. Although the magmatic history of the Lesser Antilles apparently began in the Mesozoic, its Cenozoic history is remarkably similar to the Cenozoic histories of circum-Pacific arcs. Magmatic histories in both areas suggest that island arc evolution in the Cenozoic may have worldwide synchroneity.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Silicoflagellate zonation of upper Cretaceous to lower Miocene deep-sea sediment

A stratigraphic zonation based on silicoflagellates is proposed for the division of Upper Cretaceous to lower Miocene deep-sea sediments into eight independent zones. The occurrence of silicoflagellate siliceous microfossils from Mesozoic and lower Cenozoic sediment has been poorly known in all but the middle Eocene. The most diagnostic occurrences in deep-sea sediment are here used to define a sequence of zones, which are correlated with the more widely recognizable zonation of coccoliths. The silicoflagellate zones defined include the Lyramula furcula Zone of Late Cretaceous age, the Corbisema hastata Zone of Paleocene age, the Naviculopsis constricta Zone and Dictyocha hexacantha Zone of Eocene age, the Dictyocha deflandrei Zone and Rocella gemma Zone of Oligocene age, and the Naviculopsis quadrata Zone and Distephanus octacanthus Zone of early Miocene age.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Coloradoite, acanthite, and jarosite from the Cripple Creek district, Teller County, Colorado

Coloradoite (HgTe), acanthite (Ag 2 S), and jarosite (KFe 3 (S0 4 ) 2 (OH) 6 ) have been identified in rocks from the Cripple Creek district, Colorado. Neither acanthite nor jarosite has previously been reported from this mining district. Although the occurrence of coloradoite was reported, its identification was never actually verified. The presence of acanthite may explain a discrepancy between the relative proportions of gold and silver as shown by mill reports and geochemical data.

Colorado↗
USGS1974

Thallium-bearing orpiment, Carlin gold deposit, Nevada

A variety of orpiment, As 2 S 3 , containing a significant amount of thallium has been identified in the unoxidized East ore body of the Carlin gold deposit. The mineral occurs in small veinlets with barite, calcite, quartz, and realgar.

Nevada↗
USGS1974

Occurrence of dissolved organic carbon in selected ground-water samples in the United States

A study of nonvolatile DOC (dissolved organic carbon) in ground water was conducted to establish base levels of naturally occurring dissolved organic materials. Samples of ground water were obtained at 100 sites in 27 States. Samples were pressure filtered at the time of collection and immediately frozen on dry ice. DOC concentrations were determined by wet oxidation of organic carbon to carbon dioxide which was measured by an infrared analyzer. The DOC concentrations ranged from less than the 0.1 mg/l limit of detection to 15 mg/l. Concentrations of DOC were directly correlated with specific conductance and alkalinity, but did not correlate with pH. The DOC mean concentration was 1.2 mg/l; however, the DOC median value was lower at 0.7 mg/l. Differences in DOC concentration for various types of consolidated rock aquifers were slight; for example, median DOC values for sandstone, limestone, and crystalline rock aquifer types ranged from 0.5 to 0.7 mg/l. No difference was found in the median DOC concentration between shallow (<200 ft; 61 m) and deep (>200 ft) sand and gravel aquifers.

Journal of Research of the U.S. Geological Survey↗
USGS1974

The soil creep-curved tree fallacy

No evidence has been found in eastern deciduous forests to substantiate statements that curved tree trunks, downslope tilted tree trunks, and upslope trailing tree root systems are the result of soil creep. Curvature and tilting of trunks are described as geotropic and phototropic responses to physical and physiological conditions unrelated to soil creep. The occurrence of upslope trailing of roots has not been demonstrated.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Some aspects of aquatic insect populations of pools and riffles in gravel bed streams in western United States

Relationships were studied between aquatic-insect populations on rocks of different sizes and variations of populations between different stream localities. All aquatic insects were counted and identified on streambed gravels and cobbles chosen at random from four rivers on three to four types of locations ranging from riffles to pools. The measurements used span 3 to 4 months in 1 year. Insect density (number of insects per unit of rock area) was determined to be a function of rock size. Highest insect densities occurred on rocks between 45 and 90 mm mean diameter, with larger and smaller rocks having lower insect densities. The insect population differed significantly with location within a stream; that is, from pool to riffle, as well as by stream and season.

Journal of Research of the U.S. Geological Survey↗
USGS1974

Yachats Basalt: An upper Eocene differentiated volcanic sequence in the Oregon Coast Range

The name Yadials Basalt is proposed for a sequence of largely subacrial basalt flows and breccias and associated dikes of late Eocene age that arc exposed along the central Oregon coast. These volcanic rocks, which have a maximum thickness of 750 m, are underlain by marine siltstonc of late Eocene age and overlain by marine siltstone and basaltic sandstone, also of late Eocene age. The siltstone contains a foraminiferal fauna indicative of a moderately deepwatcr marine environment, indicating that local uplift preceded the extrusion of the flows and local subsidence followed. The Yachats Basalt varies widely in composition. Although the bulk of the extrusive rocks and dikes arc basalt, some grade in composition to basaltic andcsite and andcsite; a few dikes are rhyodacitic. Most of the rocks arc porphyritic with phcnocrysts of labradorite and less commonly augite and olivine. Typical flow rock contains 50 percent SiO 2 and are characterized by high alumina, alkali, titania, and phosphate content. The wide range in composition and porphyritic character of the Yachats Basalt and the abundance of multiple dikes suggest that the magma that produced these rocks was differentiated in the upper crust before extrusion. The Yachats Basalt, and correlative upper Eocene volcanic rocks in western Oregon and Washington, lie along a generally north-trending belt. The predominance of normal faulting in western Oregon and Washington and on the adjacent continental shelf during post mid-late Eocene time suggests that the volcanics were extruded along a zone of tensional rifting. They do not appear to be related to conventional plate models for continental margins that arc characterized by deep trenches flanked by island arcs.

Oregon↗
USGS1974

Relation of mineralization to calderas in the San Juan volcanic field, southwestern Colorado

A review of the calderas in the San Juan volcanic field, southwestern Colorado, indicates that lead, zinc, copper, gold, and silver mineralization took place in and near calderas which had complex histories of postsubsidence intrusive and extrusive igneous activity. Most known ore occurs in veins that follow fractures formed during the different caldera cycles, but some intrusive bodies were extensively mineralized and possibly may host disseminated, porphyry-type deposits. The mineral deposits seem to be related most commonly to the youngest and most highly differentiated late intrusives of a caldera cycle.

Colorado↗