Periodic climate change on Mars: Review of evidence and effects on distribution of volatiles
M. H. Carr
1982, Icarus (50) 129-139
The polar regions of Mars preserve, in both their layering and their topography, a record of recent climate changes. Because of the coincidence of the growth of the northern seasonal cap with global dust storms, dust may be currently accumulating on...
Accumulation rates of Th-230, Pa-231, and some transition metals on the Bermuda Rise
M.P. Bacon, J.N. Rosholt
1982, Geochimica et Cosmochimica Acta (46) 651-666
Measurements of 238U, 234U, 230Th, 232Th, 231Pa, Mn, Fe, Co, Ni, Cu, and Zn were made on 23 samples from core GPC-5, a 29-m giant piston core from a water depth of 4583 m on the northeastern Bermuda Rise (33°41.2′N, 57°36.9′W). This area is characterized by rapid deposition of sediment transported by abyssal currents. Unsupported 230Th...
Unroofing history of a suture zone in the Himalaya of Pakistan by means of fission-track annealing ages
P.K. Zeitler, R.A.K. Tahirkheli, C. W. Naeser, N.M. Johnson
1982, Earth and Planetary Science Letters (57) 227-240
The uplift history of the Swat Valley and Hazara region of northwestern Pakistan has been established using 22 fission-track dates on apatite, zircon and sphene. A major fault, the Main Mantle Thrust (MMT) strikes east-west across the Swat Valley, separates regions...
Geochemical indices of fine sediment transport, northwest Gulf of Mexico
C. W. Holmes
1982, Journal of Sedimentary Petrology (52) 307-321
The 210 Pb distribution, the clay mineralogy distribution, and the distribution of three trace metals, barium, lead, and manganese, in the sediments of the south Texas shelf are related to the dynamics of the sedimentary transport process. 210 Pb, whose concentration is time dependent, defines three loci...
Late Pleistocene- Holocene transgressive sedimentation in deltaic and non-deltaic areas of the northeastern Bering epicontinental shelf.
C.H. Nelson
1982, Geologie en Mijnbouw (61) 5-18
The distribution of late Pleistocene and Holocene surface sediments on the northern Bering Seafloor is patchy and dependent upon locations of seafloor bedrock and pre-late Pleistocene glacial debris, late Holocene river sediment influx, and modern strong bottom currents. Seafloor vibracores and high-resolution profiles record two different sedimentary environments in the...
The oxygen isotope composition of granitoid and sedimentary rocks of the southern Snake Range, Nevada
D. E. Lee, I. Friedman, J.D. Gleason
1982, Contributions to Mineralogy and Petrology (79) 150-158
Six diverse intrusive igneous types are exposed as discrete outcrops within an area of 900 km2 in the southern Snake Range, White Pine County, Nevada. The previously recognized variety among these igneous types is reflected in the wide range of ??18O values (-1.1 to 13.4 permil) found in these rocks....
The solubilities of calcite, aragonite and vaterite in CO2-H2O solutions between 0 and 90°C, and an evaluation of the aqueous model for the system CaCO3-CO2-H2O
Niel Plummer, Eurybiades Busenberg
1982, Geochimica et Cosmochimica Acta (46) 1011-1040
Calculations based on approximately 350 new measurements (CaT-PCO2) of the solubilities of calcite, aragonite and vaterite in CO2-H2O solutions between 0 and 90°C indicate the following values for the log of the equilibrium constants KC, KA, and KV respectively, for the reaction CaCO3(s) = Ca2+ + CO2−3: <img...
The solubility of quartz in aqueous sodium chloride solution at 350°C and 180 to 500 bars
Robert O. Fournier, Robert J. Rosenbauer, James L. Bischoff
1982, Geochimica et Cosmochimica Acta (46) 1975-1978
The solubility of quartz in 2, 3, and 4 molal NaCl was measured at 350°C and pressures ranging from 180 to 500 bars. The molal solubility in each of the salt solutions is greater than that in pure water throughout the measured pressure range, with the ratio of solubility in...
Holocene sedimentation in the shallow nearshore zone off Nauset Inlet, Cape Cod, Massachusetts
D.G. Aubrey, D.C. Twichell, S.L. Pfirman
1982, Marine Geology (47) 243-259
Present conditions and sedimentary evolution of the shallow offshore region near Nauset Inlet on Cape Cod, Massachusetts were clarified using high-resolution seismic-reflection profiles, sidescan-sonar records, surface grab samples and current meter measurements. The study area contains three provinces: (1) a nearshore province (shallower than 18 m) with a relatively steep...
Seasonal growth in the bivalve Macoma balthica near the southern limit of its range
F.H. Nichols, J.K. Thompson
1982, Estuaries (5) 110-120
Shell-length growth in Macoma balthica from San Francisco Bay, California, as measured on living animals in situ, is highly seasonal despite a mild Mediterranean climate: a long period of near non-growth from May to the following February is followed by a short period of rapid growth between March and May....
An automatic optimum kernel-size selection technique for edge enhancement
Pat S. Chavez Jr., Brian P. Bauer
1982, Remote Sensing of Environment (12) 23-38
Edge enhancement is a technique that can be considered, to a first order, a correction for the modulation transfer function of an imaging system. Digital imaging systems sample a continuous function at discrete intervals so that high-frequency information cannot be recorded at the same precision as lower frequency data. Because...
Identification of the Holocene-Pleistocene boundary in the Bering Sea by diatoms.
J.G. Baldauf
1982, Boreas (11) 113-118
The modern diatom flora from surface sediment of the Navarin Basin region of the Bering Sea is dominated by Denticulopsis seminae and Nitzschia oceanica. D. seminae, a north boreal species, is most abundant in the deeper waters of the slope-basin regions, whereas N. oceanica, an Arctic species associated with ice...
Sources, sinks and storage of river sediments in the Atlantic drainage of the United States
R.H. Meade
1982, Journal of Geology (90) 235-252
The history of sediment and its movement in the Atlantic drainage demonstrate some of the difficulties of modeling sediment on a river-basin scale. Soil erosion was accelerated by a factor of at least 10 when European settlers cleared forests and planted crops. Although increasing soil-conservation practice and decreasing crop farming...
Mineralogy and stable isotope geochemistry of hydrothermally altered oceanic rocks
D.S. Stakes, J. R. O’Neil
1982, Earth and Planetary Science Letters (57) 285-304
Mineralogical and isotopic variations observed in altered glassy and crystalline rocksfrom the East Pacific Rise and the Mid-Atlantic Ridge provide information about the temperatures of alteration and seawater/rock ratios for various hydrothermal regimes within the oceanic crust. A systematic increase in alteration temperature is evident for the glassy rocksin the...
Mineralogy and geochemistry of Fe-Ti oxide and apatite (nelsonite) deposits and evaluation of the liquid immiscibility hypothesis.
A. Kolker
1982, Economic Geology (77) 1146-1158
Modal mineralogy determined for 32 Fe-Ti oxide and apatite rocks from localities in Virginia, New York, Quebec, Norway, and Sweden largely supports the 2:1 oxide:apatite ratio suggested as a eutectic mixture by Philpotts (1967). A fairly consistent suite of accessory minerals, including biotite, clinoamphibole, spinel, zircon, and sulfides, is present....
Preliminary model of regional Mesozoic groundwater flow and uranium deposition in the Colorado Plateau.
R.F. Sanford
1982, Geology (10) 348-352
Qualitative and numerical simulation of regional groundwater flow in the Colorado Plateau during Late Jurassic and Early Cretaceous time has led to a model of U deposition in areas of upwelling solutions. Palaeographic reconstruction shows that surface drainage and groundwater flow was generally to the NE and E. Groundwater flowing...
Benthic phosphorus regeneration in the Potomac River Estuary
E. Callender
1982, Hydrobiologia (91-92) 431-446
The flux of dissolved reactive phosphate from Potomac riverine and estuarine sediments is controlled by processes occurring at the water-sediment interface and within surficial sediment. In situ benthic fluxes (0.1 to 2.0 mmoles m-2 day-1) are generally five to ten times higher than calculated diffusive fluxes (0.020 to 0.30 mmoles...
Huge landslide blocks in the growth of piton de la fournaise, La réunion, and Kilauea volcano, Hawaii
Wendell A. Duffield, Laurent Stieltjes, Jacques Varet
1982, Journal of Volcanology and Geothermal Research (12) 147-160
Piton de la Fournaise, on the island of La Réunion, and Kilauea volcano, on the island of Hawaii, are active, basaltic shield volcanoes growing on the flanks of much larger shield volcanoes in intraplate tectonic environments. Past studies have shown that the average rate of magma production and the chemistry...
International geomagnetic reference field 1980: a report by IAGA Division I working group.
N.W. Peddie
1982, Geophysical Journal of the Royal Astronomical Society (68) 265-268
Describes the recommendations of the working group, which suggested additions to IGRF because of the cumulative effect of the inevitable uncertainties in the secular variation models which had led to unacceptable inaccuracies in the IGRF by the late 1970's. The recommendations were accepted by the International Association of Geomagnetism and...
Upper crustal structure of the Mount Hood, Oregon, region as revealed by time term analysis
W.M. Kohler, J. H. Healy, S.S. Wegener
1982, Journal of Geophysical Research Solid Earth (87) 339-355
Seismic refraction data with a dense areal distribution were collected to study the seismic structure of Mount Hood and the surrounding region. This area is typical of Cascade volcanoes and is geologically quite complex. The prime goals of this project were to search for velocity variations in the upper crustal...
Lead and strontium isotopes and related trace elements as genetic tracers in the Upper Cenozoic rhyolite-basalt association of the Yellowstone Plateau volcanic field
B. R. Doe, W.P. Leeman, R.L. Christiansen, C. E. Hedge
1982, Journal of Geophysical Research Solid Earth (87) 4785-4806
Supported by various field geologic and petrologic data, the contents of Pb, U, Th, Rb, and Sr and the isotopic compositions of Pb and Sr for upper Cenozoic volcanic rocks of the Yellowstone Plateau volcanic field are consistent with the hypothesis of derivation of the basaltic and rhyolitic magmas by...
Margaritasite: a new mineral of hydrothermal origin from the Pena Blanca uranium district, Mexico.
K. J. Wenrich, P.J. Modreski, R. A. Zielinski, J. L. Seeley
1982, American Mineralogist (67) 1273-1289
Margaritasite, (Cs,K,H3O)2(UO2)2V2O8.nH2O (where Cs > K, H3O and n approx 1), a 10.514, b 8.425, c 7.25 A, beta 106.01o, P21/a, Z = 2, is a newly recognized uranium ore mineral named for the Margaritas deposit, Pena Blanca uranium district, Chihuahua, Mexico, at which it was discovered. A Cs-rich analogue...
Evolution of continental crust and mantle heterogeneity: Evidence from Hf isotopes
Patchett P. Jonathan, O. Kouvo, C. E. Hedge, M. Tatsumoto
1982, Contributions to Mineralogy and Petrology (78) 279-297
We present initial 176Hf/177 Hf ratios for many samples of continental crust 3.7-0.3 Gy old. Results are based chiefly on zircons (1% Hf) and whole rocks: zircons are shown to be reliable carriers of essentially the initial Hf itself when properly chosen on the basis of U-Pb studies. Pre-3.0 Gy...
The UThPb age of equilibrated L chondrites and a solution to the excess radiogenic Pb problem in chondrites
D.M. Unruh
1982, Earth and Planetary Science Letters (58) 75-94
U, Th, and Pb analyses of whole-rock and troilite separates from seven L chondrites suggest that the excess radiogenic Pb relative to U and the large variations in PbPb model ages commonly observed in chondritic meteorites are largely due to terrestrial Pb contamination induced prior to...
The impact of entrainment and impingement on fish populations in the Hudson River estuary: Volume II: Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass Spawning stock, and the LMS Real-Time Life Cycle Model
L.W. Barnthouse, W. Van Winkle, J. Golumbek, G. F. Cada, C.P. Goodyear, S.W. Christensen, J.B. Cannon, D.W. Lee
1982, Report
No abstract available at this time...
