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At least 1,009 records · Page 56Linked to original sources
USGS1978

Stable isotope studies of bedded barite at East Northumberland Canyon in Toquima Range, central Nevada

Several beds of barite occur in the Slaven Chert at East Northumberland Canyon in the Toquima Range of central Nevada. Most of the barite is internally laminated but shows massive weathering. However, rosette, disseminated, conglomeratic, and concretionary varieties also occur. New fossil evidence from conodonts and brachiopods indicates a Late Devonian age for the Slaven Chert at East Northumberland Canyon. Preliminary δ 34 S values of most disseminated and massive-laminated barite within the Slaven Chert average about 25 permil; these are within the range of values that is typical of sulfate from Late Devonian seawater and are distinctly different from δ 34 S values of most crosscutting hydrothermal barite veins in the area. Primary δ 34 S values of the bedded barite appear to be retained during recrystallization and hydrothermal alteration, suggesting that δ 34 S data of bedded barites could be developed into a useful stratigraphic tool. The δ 34 S values of rosette and concrectionary barites range from 29.1 to 56.3 permil and indicate that these varieties of barite formed in restricted microenvironments where extensive bacterial reduction of seawater sulfate occurred. The δ 18 O data on cherts associated with the barite beds and δ 14 C and δ 18 O data on carbonate beds within the Slaven Chert indicate that the depositional environment at tames had restricted communication with normal seawater of the open ocean.

Nevada↗
USGS1977

Procedure for estimating the temperature of a hot-water component in a mixed water by using a plot of dissolved silica versus enthalpy

A graphical method using a plot of dissolved silica versus enthalpy allows quick determination of the temperature of the hot-water component of a nonboiling thermal spring. The method is applicable to warm spring waters that either have not lost heat before mixing or have lost heat by separation of steam before mixing.

Journal of Research of the U.S. Geological Survey↗
USGS1978

Factors contributing to the formation of ferromanganese nodules in Oneida Lake, New York

Oneida Lake is a large, shallow, eutrophic lake situated in the Ontario lowlands of central New York State. It contains the most concentrated deposit of freshwater ferromanganese nodules (in terms of amount per unit area) yet reported in the literature. The mineralogy and bulk chemistry of these saucer-shaped nodules are similar to the mineralogy and bulk chemistry of deep-sea ferromanganese nodules, but the nodules in Oneida Lake contain considerably lower concentrations of trace metals, especially cobalt, nickel, and copper. Budgets for iron and manganese in waters from Oneida Lake and its tributaries indicate that approximately 122 t (metric tons) of iron and 23 t of manganese are lost each year from the lake waters, presumably by incorporation into sediments and ferromanganese nodules. Estimates based on nodule abundance and age of the lake suggest that iron and manganese are being incorporated into ferromanganese nodules at rates of 13 and 22 t/yr, respectively. Most iron lost from the lake waters is apparently incorporated into sediments, which contain an average of 10 times more iron than manganese. Most manganese lost from the lake waters is apparently incorporated into ferromanganese nodules, which contain an average of 1.7 times more manganese than iron. In Oneida Lake, very high rates of phytoplankton productivity, combined with almost continuous wind mixing to the bottom, provide high-pH and high-Eh conditions in most of the lake. Algae also provide an effective means of concentrating and transporting iron and manganese and thereby aid in the extensive development of ferromanganese nodule deposits.

New York↗
USGS1977

Geochemistry of amphibolites from the central Beartooth Mountains, Montana-Wyoming

Trends of variation of major- and minor-element contents in amphibolites from the central Beartooth Mountains strongly suggest that these rocks of andesitic composition are derived from a tholeiitic, mafic igneous parent and not from a sedimentary parent. Discriminant functions based on minor-element content also indicate igneous parentage, whereas functions based on major-element content indicate a sedimentary parent, suggesting that the general assumption that the regional metamorphism is isochemical may not be entirely valid. Furthermore, chemical data on the amphibolites do not fit the fractionation curves of average Beartooth metadolerites, the most likely precursor. If, however, it is assumed that regional metamorphism and formation of amphibolites were accompanied by potassium metasomatism, then the higher concentrations of SiO 2 , Al 2 O 3 , K 2 O, and potassium-related minor elements in the amphibolites relative to metadolerite can be explained.

Montana, Wyoming↗
USGS1978

Occurrence and formation of avicennite, Tl2O3 , as a secondary mineral at the Carlin gold deposit, Nevada

Avicennite, Tl 2 O 3 , occurs as grains disseminated in silicified limestones in the upper part of the East ore zone of the Carlin gold deposit, Nevada. The avicennite is formed by the oxidation of carlinite, Tl 2 S, found in primary unoxidized carbonaceous ore immediately below the avicennite. The grains of avicennite closely resemble carlinite in size and shape. Some avicennite occurs as thin coatings on carlinite, but the time of its formation is unclear. Avicennite grains are polycrystalline, porous, dark gray to black, with a hackly fracture but no discernible cleavage. The Mohs hardness is 2.0±0.5; Vickers hardness ranges from 46.0 to 80.5 kg mm -2 . Measured density is distinctly low, 8.9 g cm -3 (or Mg m -3 ), relative to the calculated density, 10.34 g cm -3 . The mineral is isometric, space group Ia 3. a =10.5468±0.0003 angstroms or 1.05468±0.00003 nm, Z =16, and the volume of the unit cell is 1173.17±0.04 Ǻ 3 or 1.17317±0.00004 nm 3 . The most intense X-ray diffraction peaks are 3.044 (100), 1.864 (38), 2.637 (37), and 1.590 (30). In reflected light, avicennite is pale to medium gray and isotropic and lacks discernible bireflectance. Reflectance in air ranges from 10.6 to 13.0 percent. Avicennite is nearly pure Tl 2 O 3 , containing 89.6 weight percent Tl and 10.5 weight percent O by microprobe analysis. Other elements present, detected by emission spectrographic analysis, are: Pb, 300 ppm; Ca, 100 ppm; and Si, Al, Fe, Mg, Ag, Cr, Cu, Ni, and Ti, all <50 ppm.

Nevada↗
USGS1977

Geochemical and petrological studies of a uraniferous granite from the Granite Mountains, Wyoming

Granite rocks from the Granite Mountains, Wyo. have been proposed as the source of uranium deposits in the Crooks Gap, Gas Hills and Shirley Basin uranium districts, Wyoming. We have divided these granitic rocks into four units: (1) a biotitic phase which forms the dominant unit at the western end of the Granite Mountains, (2) a leucocratic phase which was found from 215 to 405 metres in drill hole GM-1, (3) silicified zones which crosscut the granitic rocks and form topographic highs, and (4) fractured zones, in drill hole GM-1, which seem to have been hydrothermally altered. The biotitic phase is hypidiomorphic-granular to xenomorphic-granular alkali granite with anomalously high contents of U (10 parts per million), Th (50 ppm), and Pb (50 ppm). Fission-track studies show that uranium is located in zircon, sphene, apatite, monzite, xenotime, biotite, chlorite, epidote, and magnetite; no intergranular uranium was found. The leucocratic phase is mineralogically similar to the biotitic phase, but contains less than half as much iron. It is xenomorphic granular and commonly contains rounded and retrograded garnets, which suggests that this phase is either metamorphic or contaminated with metamorphic materials. The leucocratic phase has anomalously high contents of U (8 ppm) and Pb (55 ppm), but has a low Th content (10 ppm). The silicified phase and fracture zones exhibit cataclastic and crystalloblastic textures and are highly variable in mineralogy. Potassium-bearing minerals are generally absent. Microcline is replaced by albite and (or) quartz, and biotite is replaced by clinozoisite. Uranium values may be anomalously high in the fracture zones. One sample contains 1100 ppm radium-equivalent uranium. In this and other uranium-rich samples from the fracture zones, the uranium is associated with iron oxides which commonly fill microfractures. According to our model and currently available data, an alkali granite is the best crystalline source rock for uranium, especially if it is unmetamorphosed and rapidly exposed to near-surface conditions for the first time when a favorable basin existed nearby.

Wyoming↗
USGS1977

A comparison of some analytical techniques for determining uranium, thorium, and potassium in granitic rocks

Geochemical exploration for uranium requires accurate and precise determinations of low-level concentrations. We have used seven different techniques and four different treatments of the fluorometric method to analyze for uranium in granitic rocks. In addition we have used four analytical techniques for thorium and three analytical techniques for potassium, two elements that are commonly present in anomalous amounts within uranium provinces. Our results show that commonly used techniques for thorium and potassium determinations are both adequately precise and accurate, but that many techniques used for uranium determinations lack the necessary precision or accuracy for complete geochemical prospecting. We suggest that a combination of delayed-neutron determinations for uranium and γ -ray spectrometric analyses for radium equivalent uranium, thorium, and potassium provides the best data base for geochemical exploration for uranium. If more detailed interpretations are desired, the combination of γ -ray spectrometry and α -spectrometry may be best. Carefully done fluorometric analyses should be adequate for water, ore, mineralized rock, and other applications where high precision and accuracy are not required.

Journal of Research of the U.S. Geological Survey↗
USGS1977

Some characteristics of Pele's hair

Pele's hair is a filamentous variety of brown sideromelane glass that forms during eruption of basaltic lava. Strands of Pele's hair form from droplets of lava that are spun or stretched into filaments during quenching, and others may form as chilled streamers of lava. Common elongate vesicles, sometimes twisted, indicate extreme stretching and twisting during hair formation. Hair diameter ranges from about 1 to 300 micrometres. Refractive index of hairs decreases with hair diameter and is most probably a function of the process of formation rather than chemical composition. Masses of Pele's hair form natural spun-glass filters that trap small particles and serve as sites for sublimate deposition. Such deposition may begin even while hair is falling to the ground through an eruption fume cloud. Sublimates include carbonates, sulfates, sulfur, and less commonly hydrocarbons, thus complicating the interpretation of volatiles in Pele's hair in terms of original magmatic constituents. Vesicles, which provide the most nearly pure samples of magmatic volatiles, contain mostly H 2 O and CO 2 .

Journal of Research of the U.S. Geological Survey↗
USGS1977

Chemical variability in the Lakeview Mountains pluton, southern California batholith: A comparison of the methods of correspondence analysis and extended Q-mode factor analysis

An extended method of Q -mode factor analysis that has been described previously offers a number of important advantages over conventional Q -mode factor analysis and correspondence analysis when applied to compositional data. Among these are the ability to compute the compositions, in the original units of the data, represented by the reference axes. The only special requirement of the data is that the values for each observation sum to a constant. Mathematically derived reference axes, such as the principal-components and varimax axes, commonly represent compositions that are partly negative. Even where no negative values are present, these compositions are comparatively difficult to interpret in petrologic terms and impossible or inappropriate to include in petrogenetic models. A model has been developed for the Lakeview Mountains pluton which employs vectors representing the compositions of melanocratic schlieren, leucocratic schlieren, and inclusions as the reference axes. When the effect of the inclusions is removed, the compositional zoning in the pluton is like that found in otherwise similar plutons in the Sierra Nevada batholith. The genetic implication of the model is that the inclusions were separated from the magma at least in its marginal parts. In the central part of the pluton, the inclusions were either separated to a lesser extent than in the marginal parts, or were reincorporated into the magma.

California↗
USGS1977

Surface deformation in part of the San Jacinto Valley, southern California

Ground fissuring and subsidence occur in a deep alluvium-filled graben between the Casa Loma and San Jacinto faults, San Jacinto Valley, southern California. These processes are attributed chiefly to compaction due to withdrawal of ground water. Subsidence due to compaction is estimated to be a maximum of 3.5 centimetres per year; tectonic subsidence of the graben is estimated to be from 0.3 to 0.6 cm per year. Ground fissuring occurs primarily on the west side of a closed depression in the graben. The area of ground fissures has expanded from 1 square kilometre in 1953 to 12 km2 in 1974 and could grow even more. Individual fissures have attained lengths of 850 metres.

California↗
USGS1977

Radiate shell structures in Paleozoic Myodocopid and Palaeocopid ostracodes are epigenetic

The radiate structures in the shell of Paleozoic ostracodes are interpreted to be epigenetic in origin. On the basis of this interpretation, the genus Radiicypridina Bless, 1973, is a junior synonym of Eocypridina Kesling and Ploch, 1960. The type-series of Eocypridina radiata (Jones, Kirkby, and Brady, 1874), from the Coal Measures of Scotland, is illustrated, and a lectotype is designated. Eocypridina aciculata , (Scott and Summerson, 1943) is a valid species, but the more elongated specimens they identified as Cypridina radiata Jones, Kirkby, and Brady, 1874, from the same collection, belong in E. aciculata . The variation in lateral outline of specimens in the Hance Formation of Kentucky is due to the orientation of the valves in the rock.

Journal of Research of the U.S. Geological Survey↗
USGS1977

Muscle scars of late Paleozoic freshwater ostracodes from West Virginia

Different adductor muscle attachment scar patterns of the three ostracode genera Darwinula Brady and Robertson, 1885, Gutschickia Scott, 1944, and Whipplella Holland, 1934, from Pennsylvanian and Permian rocks of 'West Virginia are illustrated for the first time. Gutschickia and Whipplella have been considered as junior synonyms of Carbonita Strand, 1928, and the oldest darwinulid scar pattern previously known was from the Upper Triassic of Germany. The different patterns document the presence of Darwinula in the Pennsylvanian of the United States and indicate that Whipplella and Gutschickia are valid genera. The use of ostracodes in discriminating between Carboniferous and Permian continental sedimentary rocks should be based on restudy of the species in these genera.

West Virginia↗
USGS1978

Models for calculating density and vapor pressure of geothermal brines

In a model for estimating density of a brine, the density of a natural brine at a known temperature, pressure, and composition can be calculated from the densities of the component salt solutions in the complex brine. A model for estimating vapor pressure requires two direct or indirect estimates of the vapor pressure and uses a published "reference-substance principle" to extrapolate,; these data 200° to 300° above the temperature of the highest observation. The methods can be used to estimate the partial molal volume and partial molal enthalpy of H 2 O in the natural brine and the partial molal volume change and partial molal heat change for the H2O component in the vaporization process. The equations for density and vapor pressure and the derived thermochemical properties will help in designing turbines for operation with geothermal and geopressured brines, in optimizing production conditions, and in physical and chemical modeling of a geothermal reservoir.

Journal of Research of the U.S. Geological Survey↗
USGS1978

Impact of sewerage systems on stream base flow and ground-water recharge on Long Island, New York

Statistically significant decreases in the ratio of base flow to total flow of streams along the south shore of Long Island, N.Y., are due to the use of expanding storm-sewer and sanitary-sewer networks. Base-flow losses due to sewering ranging from virtually none at Connetquot River (largely unaffected by urban development) to 211 liters per second, or a 60-percent decrease below natural levels, during 1965-74 at East Meadow Brook (which drains part of highly urbanized Nassau County). Nearly 75 percent of the baseflow loss at East Meadow Brook during 1965-74 was caused by a network of sanitary sewers west of the stream; the remainder resulted from loss of recharge in areas serviced by stream-directed storm sewers. In areas of the Carlls River basin serviced by stream-directed storm sewers, recharge depletion averaged only about 4 liter per second per square kilometer whereas in the more intensely urbanized East Meadow Brook basin, recharge depletion in such areas averaged 18 (L/s)/km 2 .

New York↗
USGS1977

Metamorphic rocks of the Yakutat-St. Elias area, south-central Alaska

Metamorphic rocks in the Yakutat-St. Elias area range in grade from zeolite to amphibolite facies. Radiometric age determinations on selected metamorphic rocks have helped to identify two major metamorphic events, one in Late Cretaceous time that was characterized by penetrative deformation, and one in the Miocene Epoch that resulted in widespread recrystallization and igneous intrusions. Mapped facies units show many discontinuities across major faults, and their distribution indicates major differential uplift between several structurally bound crustal blocks within a strongly deformed mobile belt west of the Art Lewis fault. Late Cretaceous metamorphic gradients indicate that the blocks have been tilted to the west or northwest parallel to their general structural grain. As mineral assemblages that were recrystallized during Miocene time occur on both sides of the Fairweather fault, large-scale, post-Miocene strike-slip movement along the fault is not indicated.

Alaska↗
USGS1978

Hydraulic characteristics of the White River streambed and glacial-outwash deposits at a site near Indianapolis, Indiana

An aquifer test was made in the glacial-outwash aquifer along the course of the White River in Marion County, Ind., to establish the hydraulic characteristics of this unit and the hydraulic conductivity of the White River streambed at a site 11 kilometers south of the center of downtown Indianapolis. In the immediate vicinity of the site, at a depth of about 15 meters below land surface, a clay lens separates the outwash aquifer into an upper sand and gravel unit 12 m thick and a lower unit 8.5 m thick. At the site of the test well, the clay lens is 3.0 m thick. The test was made in the upper sand and gravel unit, and data were analyzed for an assumed condition of no, or at least negligible, transient leakage from the clay lens underlying this unit. As no observation wells were installed in the clay lens, this assumption cannot be directly substantiated. However, observation wells beneath the clay lens indicated that a head loss was not induced below the clay lens by the test well, and the closeness of the values obtained for transmissivity of the upper unit by three different methods strongly supports the assumption. Results of the test include for the upper unit: lateral hydraulic conductivity, 108 meters per day; range of transmissivity (determined by three techniques), from 1400 to 1670 meters squared per day; specific yield, 0.08; and vertical hydraulic conductivity of the streambed, 2.2 m/d. These results should be of use in assessing the potential supply and in developing one of Indiana's major aquifer systems because a knowledge of aquifer characteristics is essential for proper design and spacing of wells.

Indiana↗
USGS1977

Electrical soundings near Yellow Creek, Rio Blanco County, Colorado

Ten vertical electrical soundings were made in the Piceance Creek Basin in October 1974-5 along Yellow Creek, 2 in Big Duck Creek, and 1 each along Corral Gulch, on the hill in sec. 20, 1 kilometre northwest of 84 Ranch, and along the White River between the mouths of Yellow and Piceance Creeks. Interpretations of these soundings indicate that the anisotropy of the upper oil shales decreases from 2 in the basin center to 1 at a location on its flank. This decrease could result from a greater number of vertical water-filled fractures in the upper shales near the edge of the basin. On the other hand, the anisotropy coefficient for the lower shales increases from 2 to around 9 along the same section, indicating the presence of an increasing number of isolated horizontal aquifers in the lower shales on the basin flank. It is speculated that this trend for the lower shales reverses nearer the basin edge in the area of recharge of these splintered horizontal aquifers.

Colorado↗
USGS1977

Pleistocene fishes from Alameda County, California

Six types of freshwater fishes were recovered from an early Pleistocene (Irvingtonian) locality on the east side of San Francisco Bay, Alameda County, Calif. The fauna includes one centrarchid, one salmonid, three cyprinids, and one catostomid. The fauna indicates fluvial and slow-moving or lacustrine aquatic environments. One of the cyprinids and the catostomid are assigned to provisional genera because of the inadequate amount of material available for study and the obvious differences between these fossils and known fossil or recent fishes. They are new additions to the Pleistocene fish fauna of California. Paleogeographic distribution of some of these fishes indicates former fluvial or lacustrine connections between Utah, Idaho, Oregon, Washington, Nevada, and California. The Pliocene and Pleistocene fossil fish faunas indicate the widespread occurrence of genera now endemic to California. A similar picture is presented by the molluscan evidence.

California↗