Formation and interpretation of dilatant echelon cracks
D. D. Pollard, P. Segall, P.T. Delaney
1982, Geological Society of America Bulletin (93) 1291-1303
The relative displacements of the walls of many veins, joints, and dikes demonstrate that these structures are dilatant cracks. We infer that dilatant cracks propagate in a principal stress plane, normal to the maximum tensile or least compressive stress. Arrays of echelon crack...
Biostratigraphy and structural setting of the Permian Coyote Butte Formation of central Oregon
B. R. Wardlaw, M.K. Nestell, J.T. Dutro Jr.
1982, Geology (10) 13-16
Larger isolated outcrops of the limestones of the Coyote Butte Formation consistently contain younger over older faunas that range through most of the Leonardian Series of the Early Permian. The outcrops of the Coyote Butte Formation are interpreted as right-side up blocks probably...
Stability of βMnOOH and manganese oxide deposition from springwater
J.D. Hem, C. E. Roberson, Reba B. Fournier
1982, Water Resources Research (18) 563-570
Beta MnOOH is precipitated preferentially (with respect to Mn3O4) at temperatures near O°C when Mn2+ is oxidized in aerated aqueous solutions. Upon aging in solutions open to the atmosphere a slurry of βMnOOH tends to disproportionate to form MnO2 and Mn2+. In such aged solutions, Mn2+ and H+ activities can be constant, and both...
Biostratigraphy and paleoenvironment of Miocene- Pliocene hemipelagic limestone: Kingshill Seaway, St. Croix, US Virgin Islands.
B. H. Lidz
1982, Journal of Foraminiferal Research (12) 205-233
The Kingshill Limestone and younger carbonate rocks constitute the central portion of St. Croix, forming the remains of an ancient seaway that was flanked by emergent highlands. The seaway has been filled with thick epipelagic sediments alternating with carbonate turbidites and ash falls and capped with shallow-water reefal and terrigenous...
Stream-grade variation and riparian-forest ecology along Passage Creek, Virginia
Cliff R. Hupp
1982, Bulletin of the Torrey Botanical Club (109) 488-499
Passage Creek, in northwestern Virginia, flows on relatively nonresistant shales, then cuts through a gorge underlain by resistant sandstone In the gorge, the stream gradient steepens, the size of bed material increases, a braided channel forms, and riparian-forest composition and growth form changes relative to areas outside the gorge Effects...
Palladium, platinum, rhodium, iridium and ruthenium in chromite- rich rocks from the Samail ophiolite, Oman.
N.J. Page, J.S. Pallister, M.A. Brown, J.D. Smewing, J. Haffty
1982, Canadian Mineralogist (20) 537-548
30 samples of chromitite and chromite-rich rocks from two stratigraphic sections, 250 km apart, through the basal ultramafic member of the Samail ophiolite were spectrographically analysed for platinum-group elements (PGE) and for Co, Cu, Ni and V. These data are reported as are Cr/(Cr + Al), Mg/(Mg + Fe) and...
Origin and evolution of the Nakhla meteorite inferred from the Sm-Nd and U-Pb systematics and REE, Ba, Sr, Rb and K abundances
N. Nakamura, D.M. Unruh, M. Tatsumoto, R. Hutchison
1982, Geochimica et Cosmochimica Acta (46) 1555-1573
Analyses of Sm-Nd and U-Th-Pb systematics, REE, Ba, Sr, Rb and K concentrations were carried out for whole rock and mineral separates from the Nakhla meteorite. The 1.26 ±.07 b.y. Sm-Nd age obtained in this work is in good agreement with those previously obtained by the Rb-Sr and Ar-Ar methods. The...
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 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....
Distribution, mineralogy, and texture of manganese nodules and their relation to sedimentation at DOMES Site A in the equatorial North Pacific
David Z. Piper, J. R. Blueford
1982, Deep Sea Research Part A, Oceanographic Research Papers (29) 927-951
DOMES Site A, in the equatorial North Pacific, was surveyed in detail in an attempt to relate the distribution of nodules to sedimentation. The sea floor is characterized by a broad east-west-trending valley defined by strongly dissected highlands to the north and...
Aminostratigraphy and faunal correlations of late Quaternary marine terraces, Pacific Coast, USA
G. L. Kennedy, K. R. Lajoie, J.F. Wehmiller
1982, Nature (299) 545-547
Recent studies using the extent of racemization of amino acids to date fossil mollusc shells in the Arctic1, the British Isles2 and on the Atlantic3,4 and Pacific5-13 coasts of North America have relied mainly on theoretical kinetic models of racemization. Ages generated in this fashion are highly model dependent and...
Geochemistry of a Pliocene-Pleistocene oceanic-arc plutonic complex, Guadalcanal
A.R. Chivas, A.S. Andrew, A.K. Sinha, J. R. O’Neil
1982, Nature (300) 139-143
The Koloula Igneous Complex, on the island of Guadalcanal, consists of a low-K calc-alkaline sequence of 26 different intrusive phases. The major intrusions are characterized by K/Rb>400, Rb/Sr<0.06, ?? 18O of 5.7 to 7.2 and uniform 87Sr/86Sr of 0.70372. This article presents the first data describing oxygen and strontium isotopic...
Miocene volcanism and deformation in the western Cordillera and high plateaus of south-central Peru
E.H. McKee, D. C. Noble
1982, Geological Society of America Bulletin (93) 657-662
New radiometric ages on tuffs from south-central Peru support the postulated flare-up of volcanic activity during early Miocene time. In the region of Huancavelica, Julcani, and Lircay, lower Miocene rocks lie on folded strata of pre-Cenozoic age; the absence of units of Eocene...
Ice rafting of fine-grained sediment, a sorting and transport mechanism, Beaufort Sea, Alaska
P. W. Barnes, E. Reimnitz, D. Fox
1982, Journal of Sedimentary Petrology (52) 493-502
The presence of turbid, sediment-rich fast ice in the Arctic is a major factor affecting transport of fine-grained sediment. Turbid ice was found to be present in a zone 10 to 20 km wide along the coast of the Beaufort Sea. Sediment concentrations...
Sediment deposition in a flood retention structure after two record floods in southwestern Wisconsin.
P.A. Kammerer Jr., W. G. Batten
1982, Journal of Soil and Water Conservation (37) 302-304
Sediment deposited in a flood-control structure was measured after record floods in SW Wisconsin on June 17 and June 30-July 1, 1978. The structure is in the Driftless Area, where high relief, erodible soils, and land use contribute to high soil losses. The two floods deposited 4.1 acre-ft of sediment...
Leaching of radionuclides from uranium ore and mill tailings ( Ra- 226, Tn-230).
E. R. Landa
1982, Uranium (1) 53-63
The major part of the extractable uranium is associated with a readily acid-soluble fraction in both ore and tailings. The major part of the extractable 226Ra was associated with an iron, manganese hydrous-oxide fraction in the ore and tailings. Thorium-230 was the least leachable of the radionuclides studied. The major...
Introduction: seismology and earthquake engineering in Mexico and Central and South America.
A. F. Espinosa
1982, Earthquake Information Bulletin (USGS) (14) 4-6
The results from seismological studies that are used by the engineering community are just one of the benefits obtained from research aimed at mitigating the earthquake hazard. In this issue of Earthquake Information Bulletin current programs in seismology and earthquake engineering, seismic networks, future plans and some of the cooperative...
Bank stability and channel width adjustment, East Fork River, Wyoming
E.D. Andrews
1982, Water Resources Research (18) 1184-1192
Frequent surveys of eight cross sections located in self-formed reaches of the East Fork River, Wyoming, during the 1974 snowmelt flood showed a close relation between channel morphology and scour and fill. Those cross sections narrower than the mean reach width filled at discharges less than bankfull and scoured at...
Mapping of ultramafic rocks in a heavily vegetated terrain using Landsat data
G. L. Raines, J. C. Wynn
1982, Economic Geology (77) 1755-1761
No abstract available....
Stratigraphic reference section for Georges Bank Basin - Depositional model for New England passive margin.
C. Wylie Poag
1982, American Association of Petroleum Geologists Bulletin (66) 1021-1041
A multichannel seismic reflection profile (U.S. Geological Survey line 19), calibrated with the COST G-1, COST G-2, and Shell Mohican I-100 wells, and seismic-sequence analysis shows that the chronostratigraphic and lithostratigraphic units and depositional history of the Georges Bank basin are similar to those of the Scotian basin. Carbonate rocks...
Gamma-emitting radionuclide measurements at the US geological survey national water quality laboratory, Denver, Colorado
Che Yang In, E. Ambats
1982, Nuclear Instruments and Methods (193) 197-201
Like sediment samples from Scofield Resevior in Utah were analyzed for 210Pb by the gamma-ray spectrometric method. The top 10 cm of surface sediment yielded excess 210Pb activity (excluding in situ 226Ra supported 210Pb) of 1.05 pCi/g dry weight and decreased to 0.25 pCi/g at a depth of 25 cm....
Determination of lithium isotopes at natural abundance levels by atomic absorption spectrometry
A. L. Meier
1982, Analytical Chemistry (54) 2158-2161
The relationships of the absorption of 6Li and 7Li hollow cathode lamp emissions are used to determine lithium isotopic composition in the natural abundance range of geologic materials. Absorption was found to have a nonlinear dependence upon total lithium concentration and isotopic composition. A method using nonlinear equations to describe...
Cretaceous biostratigraphy in the Wyoming thrust belt.
D. J. Nichols, S.R. Jacobson
1982, Mountain Geologist (19) 73-78
In the Cretaceous section of the thrust belt, fossils are especially useful for dating and correlating repetitive facies of different ages in structurally complex terrain. The biostratigraphic zonation for the region is based on megafossils (chiefly ammonites) , which permit accurate dating and correlation of outcrop sections, and which have...
Properties, origin and nomenclature of rodlets of the inertinite maceral group in coals of the central Appalachian basin, U.S.A.
P.C. Lyons, R. B. Finkelman, C.L. Thompson, F. W. Brown, Patrick G. Hatcher
1982, International Journal of Coal Geology (1) 313-346
Resin rodlets, sclerenchyma strands and woody splinters, which are collectively called rodlets, were studied by chemical, optical petrographic, and scanning-electron microscopic (SEM) techniques. A study was made of such rodlets from the bituminous coal beds of the central Appalachian basin (Pennsylvanian; Upper Carboniferous) of the United States. Comparisons were made...
Space platform albedo measurements as indicators of change in arid lands
C.J. Robinove
1982, Advances in Space Research (2) 31-35
The change in albedo of arid lands is an indicator of changes in their condition and quality, including density of vegetative cover, erosion, deposition, surficial soil moisture, and man-made change. In general, darkening of an arid land surface indicates an increase in land quality while brightening indicates a decrease in...
