Processes and kinetics of Cd2+ sorption by a calcareous aquifer sand
C. C. Fuller, J.A. Davis
1987, Geochimica et Cosmochimica Acta (51) 1491-1502
The rate of Cd2+ sorption by a calcareous aquifer sand was characterized by two reaction steps, with the first step reaching completion in 24 hours. The second step proceeded at a slow and nearly constant rate for at least seven days. The first step includes a fast adsorption reaction which...
The adaptive radiation of photosynthetic modes in the genus Isoetes (Isoetaceae)
Jon E. Keeley
R.M.M. Crawford, editor(s)
1987, Book chapter, Plant Life in Aquatic and Amphibious Habitats.
No abstract available at this time...
Mid-Holocene climate in Northern Minnesota
R. M. Forester, L.D. Delorme, J.P. Bradbury
1987, Quaternary Research (28) 263-273
Study of Holocene ostracodes and diatoms from Elk Lake, in North-Central Minnesota, indicates that the local climate of the mid-Holocene can be subdivided into three intervals. Throughout interval 1 (ca. 7800 to 6700 yr B.P.), climate was colder and much drier than today. During intervals 2 and 3 (ca. 6700...
Crescentic dunes on the inner continental shelf off northern California
D.A. Cacchione, M.E. Field, D.E. Drake, G. B. Tate
1987, Geology (15) 1134-1137
Large crescentic dunes that resemble barchans have been discovered within elongate scour depressions on the northern California inner continental shelf by using side-scan sonar. These dunes appear to be migrating obliquely to the regional shelf gradient; a preferred offshore direction of transport is...
Probability theory versus simulation of petroleum potential in play analysis
R. A. Crovelli
1987, Annals of Operations Research (8) 363-381
An analytic probabilistic methodology for resource appraisal of undiscovered oil and gas resources in play analysis is presented. This play-analysis methodology is a geostochastic system for petroleum resource appraisal in explored as well as frontier areas. An objective was to replace an existing Monte Carlo simulation method in order to...
Generation of liquid water on Mars through the melting of a dusty snowpack
G.D. Clow
1987, Icarus (72) 95-127
The possibility that snowmelt could have provided liquid water for valley network formation early in the history of Mars is investigated using an optical-thermal model developed for dusty snowpacks at temperate latitudes. The heating of the postulated snow is assumed to...
Maestrichtian benthic foraminifers from Ocean Point, North Slope, Alaska ( USA).
K. McDougall
1987, Journal of Foraminiferal Research (17) 344-366
Previous studies of fauna and flora from Ocean Point, Alaska, have suggested ages ranging from Campanian to early Eocene and that these assemblages are either highly endemic or commonplace. I demonstrate that the moderately abundant benthic foraminifers constitute early Maestrichtian boreal assemblages common to Canada and northern Europe. Paleoenvironmental analysis...
Integration of channel and floodplain suites. I. Developmental sequence and lateral relations of alluvial paleosols.
T. M. Bown, M. J. Kraus
1987, Journal of Sedimentary Petrology (57) 587-601
The lower Eocene Willwood Formation of the Bighorn Basin, northwest Wyoming, consists of about 770 m of alluvial rocks that exhibit extensive mechanical and geochemical modifications resulting from Eocene pedogenesis. Willwood paleosols vary considerably in their relative degrees of maturity; maturity is defined...
Quaternary silicic pyroclastic deposits of Atitlán Caldera, Guatemala
William I. Rose Jr., Christopher G. Newhall, Theodore J. Bornhorst, Stephen Self
1987, Journal of Volcanology and Geothermal Research (33) 57-80
Atitlán caldera has been the site of several silicic eruptions within the last 150,000 years, following a period of basalt/andesite volcanism. The silicic volcanism began with 5–10 km3 of rhyodacites, erupted as plinian fall and pyroclastic flows, about 126,000 yr. B.P. At 85,000 yr. B.P. 270–280 km3 of compositionally distinct rhyolite was...
Stochastic simulation of spatially correlated geo-processes
G. Christakos
1987, Mathematical Geology (19) 807-831
In this study, developments in the theory of stochastic simulation are discussed. The unifying element is the notion of Radon projection in Euclidean spaces. This notion provides a natural way of reconstructing the real process from a corresponding process observable on a reduced dimensionality space, where analysis is theoretically easier...
Multiple sources of alkanes in Quaternary oceanic sediment of Antarctica
Keith A. Kvenvolden, John B. Rapp, Margaret Golan-Bac, Frances D. Hostettler
1987, Organic Geochemistry (11) 291-302
Normal alkanes (n-C13n-C36), isoprenoid hydrocarbons (i-C15, i-C16, i-C18, i-C19, and i-C20) triterpanes (C27C32), and (C27C29) are present in low concentrations offshore Antarctica in near-surface, Quaternary sediment of the Wilkes Land continental margin and of the western Ross Sea. The distributions of these...
Chalcopyrite disease in sphalerite: pathology and epidemiology.
P. B. Barton Jr., P. M. Bethke
1987, American Mineralogist (72) 451-467
This descriptive paper identifies three widely occurring textures designated as 'watermelon', 'dusting' and 'bimodal' that characterize the replacement of original Fe-bearing sphalerite by an aggregate of chalcopyrite and low-Fe sphalerite as an integral part of the mineralization process. Replacement probably predominates over alternative modes of origin for small chalcopyrite blebs...
A model of geomagnetic secular variation for 1980-1983
N.W. Peddie, A.K. Zunde
1987, Physics of the Earth and Planetary Interiors (48) 324-329
We developed an updated model of the secular variation of the main geomagnetic field during 1980 through 1983 based on annual mean values for that interval from 148 worldwide magnetic observatories. The model consists of a series of 80 spherical harmonics, up to and including those of degree and order...
An oxygen isotope model for interpreting carbonate diagenesis in nonmarine rocks (Green River Basin, Wyoming, USA)
W. W. Dickinson
1987, Chemical Geology (65) 103-116
A closed-system model is used for predicting the δ18O of formation waters in the deep portions of the northern Green River basin, Wyoming. δ18Ocalcite is calculated from this modeled water and compared with the δ18O of measured calcites to help interpret diagenesis in the basin.The modification of 18Owater, which may be caused...
Ascaulocardium armatum (Morton 1833), new genus (Late Cretaceous): the ultimate variation on the bivalve paradigm
J. Pojeta Jr., N. F. Sohl
1987, Journal of Paleontology (61)
Cretaceous clavagellid pelecypods are a poorly known group, and have previously received little study. Ascaulocardium armatum is conchologically the most complex burrowing pelecypod known. From the study of living clavagellids, it is possible to interpret the various tubes extending outward from the adventitious crypt of A. armatum as devices...
Infragravity waves over a natural barred profile
A. H. Sallenger Jr., R.A. Holman
1987, Journal of Geophysical Research Solid Earth (92) 9531-9540
Measurements of cross-shore flow were made across the surf zone during a storm as a nearshore bar became better developed and migrated offshore. Measured infragravity band spectra were compared to synthetic spectra calculated numerically over the natural barred profile assuming a white run-up spectrum of leaky mode or high-mode edge...
Gravel bar mussel communities: a community model
A.C. Miller, B.S. Payne, T.J. Naimo, W. D. Russell-Hunter
1987, Technical Report EL-87-13
Abstract not submitted to date...
[Book review] The geochronology and evolution of Africa
Frederic H. Wilson
1987, Precambrian Research (36) 181-182
This book was written 'to provide an up-to-date data bank from which those wishing to construct models concerned with the evolution of Africa .... can draw.' As such, it attempts a survey of 'integrated geology and geochronology' of the African continent throughout the Precambrian and into the Phanerozoic. Political and...
Lungfish burrows in the Upper Triassic Chinle and Dolores Formations, Colorado Plateau
R. F. Dubiel, R.H. Blodgett, T. M. Bown
1987, Journal of Sedimentary Petrology (57) 512-521
Vertical-to-inclined, cylindrical trace fossils that occur in the Upper Triassic Chinle and Dolores Formations on the Colorado Plateau are interpreted to be the casts of lungfish burrows. The casts, which are as much as 11 cm in diameter and as much as 1.6...
Archean inheritance in zircon from late Paleozoic granites from the Avalon zone of southeastern New England: An African connection
R. E. Zartman, Hermes O. Don
1987, Earth and Planetary Science Letters (82) 305-315
In southeastern New England the Narragansett Pier Granite locally intrudes Carboniferous metasedimentary rocks of the Narragansett basin, and yields a monazite UPb Permian emplacement age of 273 ± 2Ma. Zircon from the Narragansett Pier Granite contains a...
The distribution of nitrogen species and adsorption of ammonium in sediments from the tidal Potomac River and estuary
N.S. Simon, M.M. Kennedy
1987, Estuarine, Coastal and Shelf Science (25) 11-26
The distribution of dissolved ammonium, adsorbed ammonium and residual, organic and total nitrogen was measured in Potomac River tidal, transition zone and lower estuary sediments to a depth of 66 cm. For these sediments, exchangeable ammonium, and thereby adsorbed ammonium concentrations, were determined directly using an ammonia electrode in alkaline...
Stable isotope compositions and water contents of boninite series volcanic rocks from Chichi-jima, Bonin Islands, Japan
P.F. Dobson, J. R. O’Neil
1987, Earth and Planetary Science Letters (82) 75-86
Measurements of stable isotope compositions and water contents of boninite series volcanic rocks from the island of Chichi-jima, Bonin Islands, Japan, confirm that a large amount (1.6–2.4 wt.%) of primary water was present in these unusual magmas. An enrichment of 0.6‰...
Playa-lake basins on the Southern High Plains of Texas and New Mexico: Part II. A hydrologic model and mass-balance arguments for their development.
W.W. Wood, W. R. Osterkamp
1987, Geological Society of America Bulletin (99) 224-230
Hydrologic, geologic, geomorphic, and mass-balance data suggest that most of the ∼30,000 playa lake basins on the Southern High Plains have developed by a combination of dissolution of caliche and piping of surface material into the unsaturated zone rather than by eolian processes as has generally been stated. A conceptual...
Detection of a locked zone at depth on the Parkfield, California, segment of the San Andreas fault
R.A. Harris, P. Segall
1987, Journal of Geophysical Research Solid Earth (92) 7945-7962
The Parkfield, California, segment of the San Andreas fault is transitional in character between the creeping segment of the fault to the northwest and the locked Carrizo Plain segment to the southeast. The rate of shallow fault slip decreases from 25–30 mm/yr northwest of the epicenter of the 1966 Parkfield...
Current loops fitted to geomagnetic model spherical harmonic coefficients.
L.R. Alldredge
1987, Journal of Geomagnetism & Geoelectricity (39) 271-296
One hundred-sixty circular current loops with radial axes were fitted by least squares to the 899 spherical harmonic coefficients of a 29th degree model. In the first case, the parameters that were fitted for each loop were the normalized magnetic moment, the distance from the center of the Earth...
