Evidence for a stronger oxygen-minimum zone off central California during late Pleistocene to early Holocene
J.V. Gardner, E. Hemphill-Haley
1986, Geology (14) 691-694
Of 31 deep-sea cores collected along the central California continental slope, 18 have distinctly laminated sediment at depth, but none have laminations in the top few centimetres. The cores with laminated facies are restricted to water depths between 508 and 1508 m, but...
Precambrian basement geology of North and South Dakota
J. S. Klasner, E. R. King
1986, Canadian Journal of Earth Sciences (23) 1083-1102
Combined analysis of drill-hole, gravity, and magnetic data indicates that the buried Precambrian basement rocks of the Dakotas can be divided into several lithotectonic terranes. Eastern North Dakota and northeastern South Dakota are underlain by Archean gneiss. Except for the Black Hills region of South Dakota, where Archean rocks are...
Summation of Quaternary glaciations in the United States of America
G.M. Richmond, D. S. Fullerton
1986, Quaternary Science Reviews (5) 183-196
[No abstract available]...
A united physicochemical description of the protonation and metal ion complexation equilibria of natural organic acids (humic and fulvic acids). 2. Influence of polyelectrolyte properties and functional group heterogeneity on the protonation equilibria of fulvic acid
J. Ephraim, S. Alegret, A. Mathuthu, M. Bicking, Ronald L. Malcolm, J.A. Marinsky
1986, Environmental Science & Technology (20) 354-366
No abstract available....
Image mapping with the Thematic Mapper.
A. P. Colvocoresses
1986, Photogrammetric Engineering and Remote Sensing (52) 1499-1505
This paper deals principally with Landsat Thematic Mapper (TM) image maps as published by the US Geological Survey (USGS). Landsat data have certain characteristics that make them suitable for conversion into image maps. These characteristics involve 1) spatial resolution, 2) geometric fidelity, and 3) spectral response. This paper analyzes the...
Contrasting magma types and steady-state, volume-predictable, basaltic volcanism along the Great Rift, Idaho
M. A. Kuntz, D.E. Champion, E.C. Spiker, R.H. Lefebvre
1986, Geological Society of America Bulletin (97) 579-594
The Great Rift is an 85-km-long, 2- to 8-km-wide volcanic rift zone in the Snake River Plain, Idaho. Three latest Pleistocene to Holocene basaltic lava fields, Craters of the Moon, Kings Bowl, and Wapi, are located along the Great Rift. The Craters of...
Borehole field calibration and measurement of low-concentration manganese by decay gamma rays
J.L. Mikesell, F. E. Senftle, T.A. Lloyd, A.B. Tanner, C.T. Merritt, E. R. Force
1986, Geophysics (51) 2219-2224
The manganese concentration in the Arundel clay formation, Prince Georges County, Maryland, was determined from a borehole by using delayed neutron activation. The neutrons were produced by a 100 mu g 252 Cf source. The 847 keV gamma ray of manganese was detected continuously, and its counting rate was measured at intervals...
Solid and fluid inclusions in mantle xenoliths: An analytical dilemma?
J.S. Noller
1986, Geology (14) 437-440
Two Cr-diopside Iherzolite xenoliths with kaersutite selvages, from Dish Hill, California, contain four types of solid and fluid inclusions that can be used to discriminate between actual mantle processes and processes acting upon a fragment of mantle as it is entrained and carried to the earth surface. On the basis...
Algal growth response to particle-bound orthophosphate and zinc
James S. Kuwabara, J.A. Davis, Cecily C.Y. Chang
1986, Limnology and Oceanography (31) 503-511
Effects of Zn (0-1 mu M total Zn(II)) and orthophosphate (8-12 mu M total P) additions on growth indices for the chlorophyte Selenastrum capricornutum were examined in a medium containing 50 mg liter-1 colloidal titania. Over the Zn(II) concentration range used, detrimental growth and yield effects were observed. Addition of...
Biomass and productivity of three phytoplankton size classes in San Francisco Bay
B.E. Cole, J. E. Cloern, A.E. Alpine
1986, Estuaries (9) 117-126
The 5-22 mu m size accounted for 40-50% of annual production in each embayment, but production by phytoplanton >22 mu m ranged from 26% in the S reach to 54% of total phytoplankton production in the landward embayment of the N reach. A productivity index is derived that predicts daily...
Danburite in evaporites of the Paradox basin, Utah.
O. B. Raup, B.M. Madsen
1986, Journal of Sedimentary Petrology (56) 248-251
Danburite (CaB 2 Si 2 O 8 ) has been found as nodules in Pennsylvanian age marine evaporites of the Paradox basin, Utah. Originally danburite had been known as a high-temperature mineral that occurs at numerous localities in igneous and metamorphic rocks. Since its discovery in water-insoluble residues from...
An experimental study of subaqueous slipface deposition
R. E. Hunter, G. Kocurek
1986, Journal of Sedimentary Petrology (56) 387-394
A flume study indicates that grainflow on slipfaces accounts for most cross-strata formed in unidirectional, shallow-water flows. The slipfaces studied were on small megaripples and delta-like steps (0.06-0.28 m high). During intermittent avalanching, at relatively low flow velocities, periods between avalanches were marked...
The Schwarzwalder uranium deposit, III: Alteration, vein mineralization, light stable isotopes, and genesis of the deposit
A. R. Wallace, J. F. Whelan
1986, Economic Geology (81) 872-888
The Schwartzwalder uranium deposit formed at 69.3 + or - 1.1 m.y. in a complex fracture system during the inception of Laramide uplift of the Front Range in Colorado. Geologic and isotopic evidence demonstrates that the ore-forming fluids were in chemical equilibrium with the Proterozoic metavolcanic and metasedimentary host-rock terrane...
Seismically induced landslides: current research by the US Geological Survey.
E. L. Harp, R. C. Wilson, D. K. Keefer, G. F. Wieczorek
1986, Geologia Applicata e Idrogeologia (21) 159-173
We have produced a regional seismic slope-stability map and a probabilistic prediction of landslide distribution from a postulated earthquake. For liquefaction-induced landslides, in situ measurements of seismically induced pore-water pressures have been used to establish an elastic model of pore pressure generation. -from Authors...
Lower crustal xenoliths, Chinese Peak lava flow, central Sierra Nevada
F. C. W. Dodge, L. C. Calk, R. W. Kistler
1986, Journal of Petrology (27) 1277-1304
An assemblage of pyroxenite, peridotite, and mafic granulite xenoliths contained in the toe of a 10 Ma trachybasalt flow remnant overlying Late Cretaceous granitoids indicates the presence of a mafic-ultramafic complex beneath the Sierra Nevada batholith. Olivine-free pyroxenites that include orthopyroxenites, websterites, and clinopyroxenites are dominant. Primary igneous textures...
Satellite orientation and position for geometric correction of scanner imagery.
P.H. Salamonowicz
1986, Photogrammetric Engineering and Remote Sensing (52) 491-499
The USGS Mini Image Processing System currently relies on a polynomial method for geometric correction of Landsat multispectral scanner (MSS) data. A large number of ground control points are required because polynomials do not model the sources of error. In order to reduce the number of necessary points, a set...
Kassite from the Diamond Jo quarry, Magnet Cove, Hot Spring County, Arkansas: The problem of cafetite and kassite
H. T. Evans Jr., E.J. Dwornik, C. Milton
1986, American Mineralogist (71) 1045-1048
Small (<0.5 mm), brownish-pink platy rosettes and yellow spherules, in cavities in nepheline syenite at the Diamond Jo quarry, Magnet Cove, Hot Spring County, Arkansas, have been identified as kassite, CaTi2O4(OH)2, a mineral previously known only from the Kola Peninsula, USSR. The Magnet Cove kassite is orthorhombic, in...
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...
Submarine fissure eruptions and hydrothermal vents on the southern Juan de Fuca Ridge: preliminary observations from the submersible Alvin
W. R. Normark
1986, Geology (14) 823-827
The submersible Alvin was used to investigate 3 active hydrothermal discharge sites along the S Juan de Fuca Ridge in September 1984. The hydrothermal zones occur within a 10-30m-deep, 30-50m-wide cleft marking the center of the axial valley. This cleft is the eruptive locus for the axial valley. The hydrothermal...
Dissolved organic matter in anoxic pore waters from Mangrove Lake, Bermuda
W. H. Orem, Patrick G. Hatcher, E.C. Spiker, N.M. Szeverenyi, G.E. Maciel
1986, Geochimica et Cosmochimica Acta (50) 609-618
Dissolved organic matter and dissolved inorganic chemical species in anoxic pore water from Mangrove Lake, Bermuda sediments were studied to evaluate the role of pore water in the early diagenesis of organic matter. Dissolved sulphate, titration alkalinity, phosphate, and ammonia concentration versus depth profiles were typical of many nearshore clastic sediments and...
Regression approximations for transport model constraint sets in combined aquifer simulation-optimization studies
William M. Alley
1986, Water Resources Research (22) 581-586
Problems involving the combined use of contaminant transport models and nonlinear optimization schemes can be very expensive to solve. This paper explores the use of transport models with ordinary regression and regression on ranks to develop approximate response functions of concentrations at critical locations as a function of pumping and...
Air abrasion experiments in U-Pb dating of zircon
S. S. Goldich, L. B. Fischer
1986, Chemical Geology (58) 195-215
Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age. Age discordance...
EFFECTS OF ARTIFICIAL RECHARGE ON GROUND-WATER QUALITY, LONG ISLAND, NEW YORK.
Brian J. Schneider, Henry F. H. Ku, Edward T. Oaksford
1986, Conference Paper
Artificial-recharge experiments were conducted at East Meadow in central Nassau County, Long Island, N. Y. , from October 1982 through January 1984, to evaluate the degree of ground-water mounding and chemical effects of artificially replenishing the ground-water system with tertiary-treated wastewater. Reclaimed water was provided by the Cedar Creek wastewater-treatment...
New method for the measurement of osmium isotopes applied to a New Zealand Cretaceous/Tertiary boundary shale
F.E. Lichte, S.M. Wilson, R.R. Brooks, R.D. Reeves, J. Holzbecher, D.E. Ryan
1986, Nature (322) 816-817
The determination of osmium content and isotopic abundances in geological materials has received increasing attention in recent years following the proposal of Alvarez et al.1 that mass extinctions at the end of the Cretaceous period were caused by the impact of a large (???10km) meteorite which left anomalously high iridium...
Eureka Quartzite in Mexico? - Tectonic implications
K. B. Ketner
1986, Geology (14) 1027-1030
At Cerro Cobachi, 90 km east of Hermosillo, Sonora, an Ordovician to Permian miogeoclinal assemblage and an Ordovician to Permian siliceous deep-water assemblage were juxtaposed by thrust faulting between mid-Permian and latest Cretaceous time. Both assemblages resemble counterparts in the Great Basin. One...
