Geology and tin-greisen mineralization of the Akash granite, northern Arabian Shield
K.S. Kellogg, C. W. Smith
1986, Journal of African Earth Sciences (4) 205-210
The western margin of the postorogenic Akash granite, 30 km E of Ha'il in the northern Arabian Shield, is greisenized and contains anomalous concentrations of Sn. The pluton intrudes metamorphic and intrusive rocks, and crops out as a 10 by...
Cambrian nepheline syenite complex at Jabal Sawda, Midyan region, Kingdom of Saudi Arabia
W.K. Liddicoat, C.R. Ramsay, C. E. Hedge
1986, Journal of African Earth Sciences (4) 139-150
The only nepheline syenite complex presently known in the Arabian Shield is at Jabal Sawda, about 30 km S of Haql in the extreme NW of Saudi Arabia. It is a post-tectonic, composite intrusion with a crudely concentric structure. A...
Luminous phenomena and earthquakes in southern Washington
J.S. Derr, M.A. Persinger
1986, Experientia (42) 991-999
Luminous phenomena, mostly nocturnal lights, are associated with very small earthquakes in southern Washington state. The phenomena seem to be electrical in nature, related to earthquake lights, and tend to occur when the locus of earthquake activity moves across an active fault in an area of compressional stress. ?? 1986...
Stratigraphic setting and mineralogy of the Arctic volcanogenic massive sulfide prospect, Ambler district, Alaska
J.M. Schmidt
1986, Economic Geology (81) 1619-1643
The Arctic prospect, south central Brooks Range, is among the 30 largest of 508 volcanic-hosted massive sulphide deposits in the world. The massive sulphide lenses are interlayered with graphitic schist between metamorphosed rhyolite porphyries in Middle Devonian to early Mississippian metamorphosed volcanic, volcaniclastic and sedimentary rocks. Hydrothermal alteration is of...
Automated mapping of the ocean floor using the theory of intrinsic random functions of order k
M. David, D. Crozel, James M. Robb
1986, Marine Geophysical Research (8) 49-74
High-quality contour maps can be computer drawn from single track echo-sounding data by combining Universal Kriging and the theory of intrinsic random function of order K (IRFK). These methods interpolate values among the closely spaced points that lie along relatively widely spaced lines. The technique provides a variance which can...
Spectral reflectance of carbonatites and related alkalic igneous rocks: Selected samples from four North American localities
L. C. Rowan, M.J. Kingston, J.K. Crowley
1986, Economic Geology (81) 857-871
Laboratory spectral reflectance measurements were made in the 0.4- to 2.5-mu m wavelength range for samples collected from four North American carbonatite-alkalic igneous rock complexes. Alkalic rock spectra produced few absorption features; however, the carbonatites typically showed conspicuous carbonate, ferric and ferrous iron, and in some cases rare earth element...
The valence of sulfur in disulfides: An overlooked clue to the genesis of Mississippi Valley-type lead-zinc deposits
C.S. Spirakis
1986, Economic Geology (81) 1544-1545
No abstract available....
Gas analyses from the Pu'u O'o eruption in 1985, Kilauea volcano, Hawaii
L. P. Greenland
1986, Bulletin of Volcanology (48) 341-348
Volcanic gas samples were collected from July to November 1985 from a lava pond in the main eruptive conduit of Pu'u O'o from a 2-week-long fissure eruption and from a minor flank eruption of Pu'u O'o. The molecular composition of these gases is consistent with thermodynamic equilibrium at a temperature...
Sr, Nd and Pb isotopes in Proterozoic intrusives astride the Grenville Front in Labrador: Implications for crustal contamination and basement mapping
L.D. Ashwal, J. L. Wooden, R.F. Emslie
1986, Geochimica et Cosmochimica Acta (50) 2571-2585
We report Sr, Nd and Pb isotopic compositions of mid-Proterozoic anorthosites and related rocks (1.45-1.65 Ga) and of younger olivine diabase dikes (1.4 Ga) from two complexes on either side of the Grenville Front in Labrador. Anorthositic or diabasic samples from the Mealy Mountains (Grenville Province) and Harp Lake (Nain-Churchill...
Obstacles facing the venus radar mapper - The implications of gestalt formation in stereo-radargrammetry
R.L. Wildey
1986, Earth, Moon and Planets (35) 47-54
The question of adapting to radar images the existing hardware that form topographic maps through stereo-photogrammetric models, is examined in principle. Such hardware utilizes a human/ computer hybrid. Although the problem of brightness differentials between corresponding landmarks can be dealt with pseudo-photoclinometrically, the main problem is whether the perspective in...
Isotopic constraints on the origin of the Atlantis II, Suakin and Valdivia brines, Red Sea
R.A. Zierenberg, Wayne C. Shanks III
1986, Geochimica et Cosmochimica Acta (50) 2205-2214
The origin of three Red Sea submarine brine pools was investigated by analysis of the S and O isotope ratios of dissolved sulfate and Sr isotope ratios of dissolved Sr in the brines. Sulfur and O isotope ratios of sulfate and Sr isotope ratios of evaporitic source rocks for the...
10Be distribution in soils from Merced River terraces, California
M.J. Pavich, L. Brown, J. Harden, J. Klein, R. Middleton
1986, Geochimica et Cosmochimica Acta (50) 1727-1735
The distribution and residence time of cosmogenic 10Be in clay-rich soil horizons is fundamental to understanding and modelling the migration of 10Be on terrestrial sediments and in groundwater solutions. We have analyzed seven profiles of clay-rich soils developed from terrace sediments of the Merced River, California. The terraces and soils of increasing...
Estimating monthly streamflow values by cokriging
A.R. Solow, S.M. Gorelick
1986, Mathematical Geology (18) 785-809
Cokriging is applied to estimation of missing monthly streamflow values in three records from gaging stations in west central Virginia. Missing values are estimated from optimal consideration of the pattern of auto- and cross-correlation among standardized residual log-flow records. Investigation of the sensitivity of estimation to data configuration showed that...
The system NaCl-H2O: relations of vapor-liquid near the critical temperature of water and of vapor-liquid-halite from 300° to 500°C
James L. Bischoff, Robert J. Rosenbauer, Kenneth S. Pitzer
1986, Geochimica et Cosmochimica Acta (50) 1437-1444
Vapor-liquid relations (P-T-x) for the system NaCl-H2O were determined experimentally at temperatures spanning the critical temperature of water (Tc), the lowest temperature in the system at which critical behavior occurs. In addition, vapor-liquid-halite P-T-x(vapor) relations were determined from 300° to 500°C. Results show that at 373.0°C, immediately below Tc, the vapor side...
Alternate forms of the associated Legendre functions for use in geomagnetic modeling.
L.R. Alldredge, E.R. Benton
1986, Journal of Geomagnetism & Geoelectricity (38) 599-609
An inconvenience attending traditional use of associated Legendre functions in global modeling is that the functions are not separable with respect to the two indices (order and degree). In 1973 Merilees suggested a way to avoid the problem by showing that associated Legendre functions of order m and degree m+k can be expressed in...
Local Magnetic Fields, Uplift, Gravity, and Dilational Strain Changes in Southern California
M.J.S. Johnston
1986, Journal of Geomagnetism & Geoelectricity (38) 933-947
Measurements of regional magnetic field during gravity, strain and leveling surveys near the San Andreas fault at Cajon, Palmdale and Tejon are strongly correlated with changes in gravity, areal strain, and uplift in these regions during the period 1977-1984. This correlation principally depends on data taken during 1978-79...
ON NONSTATIONARY STOCHASTIC MODELS FOR EARTHQUAKES.
Erdal Safak, David M. Boore
1986, Conference Paper
A seismological stochastic model for earthquake ground-motion description is presented. Seismological models are based on the physical properties of the source and the medium and have significant advantages over the widely used empirical models. The model discussed here provides a convenient form for estimating structural response by using random vibration...
The Valley and Ridge Province of eastern Pennsylvania - Stratigraphic and sedimentologic contributions and problems
Jack B. Epstein
1986, Geological Journal (21) 283-306
Many contributions that have led to a better understanding of Appalachian geology have resulted directly from work in the folded Appalachian Mountain and Great Valley sections of the Valley and Ridge physiographic province of eastern Pennsylvania. Disagreements have been common since H.D. Rogers first described the geology of the area...
Fumarole emissions at Mount St. Helens volcano, June 1980 to October 1981: Degassing of a magma-hydrothermal system
T.M. Gerlach, T. J. Casadevall
1986, Journal of Volcanology and Geothermal Research (28) 141-160
This study is an investigation of the chemical changes in the Mount St. Helens fumarole gases up to October 1981, the sources of the fumarole gases, and the stability of gas species in the shallow magma system. These problems are investigated by calculations of element compositions, thermodynamic equilibria, and magmatic...
A computerized particle-size analysis system
L.J. Poppe, A.H. Eliason, J.J. Fredericks
1986, Computers & Geosciences (12) 93-96
[No abstract available]...
FEATURE OF THE 3 MARCH 1985 CHILE EARTHQUAKE - POSSIBLE TERRAIN AMPLIFICATION.
M. Çelebi
1986, Conference Paper
This paper presents results of site-response experiments performed five months after the M//s equals 7. 8 Central Chile Earthquake of 3 March 1985. The objectives of the experiments performed are to identify amplification due to topography and geology. Topographical amplification at Canal Beagle, a subdivision of Vina del Mar, was...
COMPARISON OF FOUR ARTIFICIAL SUBSTRATES AND THE PONAR GRAB FOR BENTHIC INVERTEBRATE COLLECTION.
Keith V. Slack, Rodger F. Ferreira, Robert C. Averett
1986, Water Resources Bulletin (22) 237-248
Four different bottom-placed artificial substrates were compared with the Ponar grab for collecting benthic invertebrates. Artificial substrate samples of organisms were larger and more diverse than those of the grab. Barbeque Basket samplers caught the most taxa and individuals and Beak Trays caught the least. Chironomids and crustaceans were dominant...
Metamorphosed melange terrane in the eastern Piedmont of North Carolina
J. Wright Horton Jr., D.E. Blake, A.S. Wylie Jr., E.F. Stoddard
1986, Geology (14) 551-553
The Falls Lake melange crops out in the eastern Piedmont of North Carolina between the Carolina slate belt and the Raleigh belt. The melange is composed of mafic and ultramafic blocks and pods of diverse shapes and sizes, dispersed without apparent stratigraphic continuity,...
Reply to "possible non-equilibrium oxygen isotope effects in mantle nodules, an alternative to the Kyser-O'Neil-Carmichael18O/16O geothermometer"
Kyser T. Kurtis, J. R. O’Neil, I. S. E. Carmichael
1986, Contributions to Mineralogy and Petrology (93) 120-123
[No abstract available]...
Simulation of fluid flow and energy transport processes associated with high-level radioactive waste disposal in unsaturated alluvium
David W. Pollock
1986, Water Resources Research (22) 765-775
Many parts of the Great Basin have thick zones of unsaturated alluvium which might be suitable for disposing of high-level radioactive wastes. A mathematical model accounting for the coupled transport of energy, water (vapor and liquid), and dry air was used to analyze one-dimensional, vertical transport above and below an...
