Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium
J.D. Hem, Carol J. Lind
1991, Geochimica et Cosmochimica Acta (55) 2435-2451
Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn2+ and Cd2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd2Mn34+O8, Mn2+2Mn4+3O8, MnO2 (ramsdellite), and CdCO3. Mean oxidation...
Large-scale variation in lithospheric structure along and across the Kenya rift
C. Prodehl, J. Mechie, W. Kaminski, K. Fuchs, C. Grosse, H. Hoffmann, R. Stangl, R. Stellrecht, M.A. Khan, Peter K.H. Maguire, W. Kirk, Gordon R. Keller, A. Githui, M. Baker, Walter D. Mooney, E. Criley, J. Luetgert, B. Jacob, H. Thybo, M. Demartin, S. Scarascia, A. Hirn, J. R. Bowman, I. Nyambok, S. Gaciri, J. Patel, E. Dindi, D.H. Griffiths, R.F. King, A. E. Mussett, L.W. Braile, G. Thompson, K. Olsen, S. Harder, R. Vees, D. Gajewski, A. Schulte, J. Obel, F. Mwango, J. Mukinya, D. Riaroh
1991, Nature (354) 223-227
The Kenya rift is one of the classic examples of a continental rift zone: models for its evolution range from extension of the lithosphere by pure shear1, through extension by simple shear2, to diapiric upwelling of an asthenolith3. Following a pilot study in 19854, the present work involved the shooting...
A statistical approach to the interpretation of aliphatic hydrocarbon distributions in marine sediments
J. B. Rapp
1991, Chemical Geology (93) 163-177
Q-mode factor analysis was used to quantitate the distribution of the major aliphatic hydrocarbon (n-alkanes, pristane, phytane) systems in sediments from a variety of marine environments. The compositions of the pure end members of the systems were obtained from factor scores and the distribution of the systems within each sample...
Biomarkers in Tertiary mélange, western Olympic Peninsula, Washington, U.S.A.
Keith A. Kvenvolden, Frances D. Hostettler, John B. Rapp, Parke D. Snavely Jr.
1991, Chemical Geology (93) 101-110
Middle Eocene to middle Miocene mélange and broken formations are exposed in the coastal outcrops along the west side of the Olympic Peninsula, Washington. A petroleum geochemical assessment of these geologic units has included the investigation of biomarker compounds. A comparison was made of biomarkers in an oil sample from...
Porosity trends of the Lower Cretaceous J Sandstone, Denver Basin, Colorado
J. W. Schmoker, D.K. Higley
1991, Journal of Sedimentary Petrology (61) 909-920
This study examines relationships between porosity and time-temperature history, and the influence of rock properties upon porosity, for the Lower Cretaceous J Sandstone in the Colorado portion of the Denver basin. The J Sandstone is classified as a quartzarenite to litharenite and was...
Institutional issues affecting the integration and use of remotely sensed data and geographic information systems
D. T. Lauer, J. E. Estes, J.R. Jensen, D. D. Greenlee
1991, Photogrammetric Engineering and Remote Sensing (57) 647-654
The developers as well as the users of remotely sensed data and geographic information system (GIS) techniques are associated with nearly all types of institutions in government, industry, and academia. Individuals in these various institutions often find the barriers to accepting remote sensing and GIS are not necessarily technical in...
Chemical equilibrium and mass balance relationships associated with the Long Valley hydrothermal system, California, U.S.A.
A. F. White, M. L. Peterson
1991, Journal of Volcanology and Geothermal Research (48) 283-302
Recent drilling and sampling of hydrothermal fluids from Long Valley permit an accurate characterization of chemical concentrations and equilibrium conditions in the hydrothermal reservoir. Hydrothermal fluids are thermodynamically saturated with secondary quartz, calcite, and pyrite but are in disequilibrium with respect to aqueous sulfide-sulfate speciation. Hydrothermal fluids are enriched in...
Employment of Gibbs-Donnan-based concepts for interpretation of the properties of linear polyelectrolyte solutions
J.A. Marinsky, M.M. Reddy
1991, Journal of Physical Chemistry (95) 10208-10214
Earlier research has shown that the acid dissociation and metal ion complexation equilibria of linear, weak-acid polyelectrolytes and their cross-linked gel analogues are similarly sensitive to the counterion concentration levels of their solutions. Gibbs-Donnan-based concepts, applicable to the gel, are equally applicable to the linear polyelectrolyte for the accommodation of...
Chloride cycling in two forested lake watersheds in the west-central Adirondack Mountains, New York, U.S.A.
N.E. Peters
1991, Water, Air, & Soil Pollution (59) 201-215
The chemistry of precipitation, throughfall, soil water, ground water, and surface water was evaluated in two forested lake-watersheds over a 4-yr period to assess factors controlling C1- cycling. Results indicate that C1- cycling in these watersheds is more complex than the generally held view of the rapid transport of atmospherically...
Relation between the national handbook of recommended methods for water data acquisition and ASTM standards
G. Douglas Glysson, John V. Skinner
1991, Conference Paper, ASTM Special Technical Publication
In the late 1950's, intense demands for water and growing concerns about declines in the quality of water generated the need for more water-resources data. About thirty Federal agencies, hundreds of State, county and local agencies, and many private organizations had been collecting water data. However, because of differences in...
Surface features of central North America: a synoptic view from computer graphics
R.J. Pike
1991, GSA Today (1) 1-251
A digital shaded-relief image of the 48 contiguous United States shows the details of large- and small-scale landforms, including several linear trends. The features faithfully reflect tectonism, continental glaciation, fluvial activity, volcanism, and other surface-shaping events and processes. The new map not only depicts topography accurately and in its true...
Nd, Sr, and O isotopic variations in metaluminous ash-flow tuffs and related volcanic rocks at the Timber Mountain/Oasis Valley Caldera, Complex, SW Nevada: implications for the origin and evolution of large-volume silicic magma bodies
G. L. Farmer, D.E. Broxton, R.G. Warren, W. Pickthorn
1991, Contributions to Mineralogy and Petrology (109) 53-68
Nd, Sr and O isotopic data were obtained from silicic ash-flow tuffs and lavas at the Tertiary age (16-9 Ma) Timber (Mountain/Oasis Valley volcanic center (TMOV) in southern Nevada, to assess models for the origin and evolution of the large-volume silicic magma bodies generated in this region. The large-volume (>900...
Crustal structure of the western New England Appalachians and the Adirondack Mountains
S. Hughes, J.H. Leutgert
1991, Journal of Geophysical Research (96)
Presents an interpretation of the crustal velocity structure based on a seismic refraction/wide-angle reflection experiment in eastern North America extending from the Adirondacks in New York State through the northern Appalachians in Vermont and New Hampshire to central Maine. Modeling of the eastern portion of the profile within the New...
Age and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36Cl and 14C in rock varnish
F. M. Phillips, M.G. Zreda, S.S. Smith, D. Elmore, P.W. Kubik, R.I. Dorn, D. J. Roddy
1991, Geochimica et Cosmochimica Acta (55) 2695-2698
Using cosmogenic 36Cl buildup and rock varnish radiocarbon, we have measured the exposure age of rock surfaces at Meteor Crater, Arizona. Our 36Cl measurements on four dolomite boulders ejected from the crater by the impact yield a mean age of 49.7 ± 0.85 ka, which is in excellent agreement with an average...
An analytical method for hydrogeochemical surveys: Inductively coupled plasma-atomic emission spectrometry after using enrichment coprecipitation with cobalt and ammonium pyrrolidine dithiocarbamate
D.M. Hopkins
1991, Journal of Geochemical Exploration (41) 349-361
Trace metals that are commonly associated with mineralization were concentrated and separated from natural water by coprecipitation with ammonium pyrollidine dithiocarbamate (APDC) and cobalt and determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The method is useful in hydrogeochemical surveys because it permits preconcentration near the sample sites, and selected...
Tritium concentrations in the active Pu'u O'o crater, Kilauea volcano, Hawaii: implications for cold fusion in the Earth's interior
J. E. Quick, T. K. Hinkley, G.M. Reimer, C. E. Hedge
1991, Physics of the Earth and Planetary Interiors (69) 132-137
The assertion that deuterium-deuterium fusion may occur at low temperature suggests a potential new source of geothermal heat. If a cold-fusion-like process occurs within the Earth, then a test for its existence would be a search for anomalous tritium in volcanic emissions. The Pu'u O'o crater is the first point...
Vanadium accumulation in carbonaceous rocks: A review of geochemical controls during deposition and diagenesis
G. N. Breit, R. B. Wanty
1991, Chemical Geology (91) 83-97
Published data relevant to the geochemistry of vanadium were used to evaluate processes and conditions that control vanadium accumulation in carbonaceous rocks. Reduction, adsorption, and complexation of dissolved vanadium favor addition of vanadium to sediments rich in organic carbon. Dissolved vanadate (V(V)) species predominate in oxic seawater and are reduced...
Proposed method of hydrogeochemical exploration for salt deposits using ClBr ratios, Eastern Province, Kingdom of Saudi Arabia
C. L. Smith
1991, Applied Geochemistry (6) 249-255
Despite the value of the salt (NaCl) and brine used by the chemical industry, geochemical prospecting techniques are not customarily employed in the search for these raw materials. In this study, Br geochemistry is used as the basis for a proposed hydrogeochemical prospecting technique that was designed to search for...
MBSSAS: A code for the computation of margules parameters and equilibrium relations in binary solid-solution aqueous-solution systems
P. D. Glynn
1991, Computers & Geosciences (17) 907-966
The computer code MBSSAS uses two-parameter Margules-type excess-free-energy of mixing equations to calculate thermodynamic equilibrium, pure-phase saturation, and stoichiometric saturation states in binary solid-solution aqueous-solution (SSAS) systems. Lippmann phase diagrams, Roozeboom diagrams, and distribution-coefficient diagrams can be constructed from the output data files,...
Reconciliation of stress and structural histories of the Tharsis region of Mars
K. L. Tanaka, M.P. Golombek, W.B. Banerdt
1991, Journal of Geophysical Research (96) 15617-15633
We present a new compilation of the structural and stratigraphic evolution of the Tharsis region of Mars that incorporates recent advances in understanding its stratigraphy, and we introduce a lithospheric deformation model that can account for the observations. The first period in the formation of...
UDATE1: A computer program for the calculation of uranium-series isotopic ages
R.J. Rosenbauer
1991, Computers & Geosciences (17) 45-75
UDATE1 is a FORTRAN-77 program with an interface for an Apple Macintosh computer that calculates isotope activities from measured count rates to date geologic materials by uranium-series disequilibria. Dates on pure samples can be determined directly by the accumulation of 230Th from 234U and of 231Pa from 235U. Dates for...
Tertiary fission-track ages from the Bagua syncline (northern Peru): Stratigraphic and tectonic implications
C. W. Naeser, J.-Y. Crochet, E. Jaillard, G. Laubacher, T. Mourier, B. Sige
1991, Journal of South American Earth Sciences (4) 61-71
The results of five zircon fission-track ages of volcanic tuffs intercalated within the continental deposits of the Bagua syncline (northern Peru) are reported. These 2500-meter-thick deposits overlie mid-Campanian to lower Maastrichtian fine-grained red beds (Fundo El Triunfo Formation). The disconformable fluvial conglomerates of the Rentema Formation are associated with a...
The interaction between biology and the management of aquatic macrophytes
S. A. Nichols
1991, Aquatic Botany (41) 225-252
‘Management’ refers to controlling nuisance aquatic species and to restoring or restructing aquatic plant communities. Producing stable, diverse, aquatic plant communities containing a high percentage of desirable species is a primary management goal.There are a variety of techniques including harvesting, herbicides, water-level fluctuation, sediment alteration, nutrient limitation, light alteration, and...
In situ 10Be-26Al exposure ages at Meteor Crater, Arizona
K. Nishiizumi, C.P. Kohl, E.M. Shoemaker, J.R. Arnold, J. Klein, D. Fink, R. Middleton
1991, Geochimica et Cosmochimica Acta (55) 2699-2703
A new method of dating the surface exposure of rocks from in situ production of 10Be and 26Al has been applied to determine the age of Meteor Crater, Arizona. A lower bound on the crater age of 49,200 ± 1,700 years has been obtained by this...
Data standardization. The key to effective management
C. Russell Wagner
1991, Conference Paper, ASTM Special Technical Publication
Effective management of the nation's water resources is dependent upon accurate and consistent hydrologic information. Before the emergence of environmental concerns in the 1960's, most hydrologic information was collected by the U.S. Geological Survey and other Federal agencies that used fairly consistent methods and equipment. In the past quarter century,...
