Fluid inclusions in vadose cement with consistent vapor to liquid ratios, Pleistocene Miami Limestone, southeastern Florida
C.E. Barker, R. B. Halley
1988, Geochimica et Cosmochimica Acta (52) 1019-1025
Vadose cements in the Late Pleistocene Miami Limestone contain regions with two-phase aqueous fluid inclusions that have consistent vapor to liquid (V-L) ratios. When heated, these seemingly primary inclusions homogenize to a liquid phase in a range between 75°C and 130°C (mean = 100°C) and have final melting temperatures between...
Sr and Nd isotopic variations in ferromanganese crusts from the Central Pacific: Implications for age and source provenance
K. Futa, Z. E. Peterman, J.R. Hein
1988, Geochimica et Cosmochimica Acta (52) 2229-2233
Isotopic analyses of two hydrogenetic ferromanganese (Fe-Mn) crusts from volcanic edifices in the central Pacific Ocean reveal systematic variations in 87Sr86Sr">87Sr86Sr and 143Nd144Nd">143Nd144Nd, with both ratios decreasing as a function of depth into the Fe-Mn crusts. Leaching experiments suggest that Sr...
High-resolution 40Ar 39Ar chronology of Oligocene volcanic rocks, San Juan Mountains, Colorado
M. A. Lanphere
1988, Geochimica et Cosmochimica Acta (52) 1425-1434
The central San Juan caldera complex consists of seven calderas from which eight major ash-flow tuffs were erupted during a period of intense volcanic activity that lasted for approximately 2 m.y. about 26–28 Ma. The analytical precision of conventional K-Ar dating in this time interval is not sufficient to unambiguously...
A climatic-limnologic model of diatom succession for paleolimnological interpretation of varved sediments at Elk Lake, Minnesota
Bradbury J. Platt
1988, Journal of Paleolimnology (1) 115-131
Sediment traps placed in the profundal region of Elk Lake, north central Minnesota during the 1979 spring and 1983-84 fall and spring seasons monitored seasonal diatom production for two climatically distinctive periods. The spring of 1979 was one of the coldest and wettest on record. Ice out at Elk Lake...
Methane cycling in the sediments of Lake Washington
K.M. Kuivila, J.W. Murray, A.H. Devol, M.E. Lidstrom, C.E. Reimers
1988, Limnology and Oceanography (33) 571-581
About half of the methane flux from depth is oxidized to CO2 in the upper 0.7 cm of the sediments and the remainder escapes into the water column. In terms of the total carbon budget of the lake, the upward flux of methane is insignificant with only about 2% of...
The metal oxide fraction of pelagic sediment in the equatorial North Pacific Ocean: A source of metals in ferromanganese nodules
D.Z. Piper
1988, Geochimica et Cosmochimica Acta (52) 2127-2145
Pelagic sediment recovered at DOMES Site A in the equatorial North Pacific (151°W, 9° 15′N) consists of a surface homogeneous layer, approximately 10 cm thick, overlying a strongly mottled layer that is lighter in color. The radiolarian composition of both units is Quaternary. In areas where this sediment was only...
Isotopic evidence for organic matter oxidation by manganese reduction in the formation of stratiform manganese carbonate ore
P.M. Okita, J.B. Maynard, E.C. Spiker, E. R. Force
1988, Geochimica et Cosmochimica Acta (52) 2679-2685
Unlike other marine-sedimentary manganese ore deposits, which are largely composed of manganese oxides, the primary ore at Molango (Hidalgo State, Mexico) is exclusively manganese carbonate (rhodochrosite, Mn-calcite, kutnahorite). Stable isotope studies of the carbonates from Molango provide critical new information relevant to the controversy over syngenetic and diagenetic models of...
Environmental impacts and regulatory policy. Implications of spray disposal of dredged material in Louisiana wetlands
Donald R. Cahoon, J.H. Cowan Jr.
1988, Coastal Management (16) 341-362
The capabilities of a new wetland dredging technology were assessed along with associated newly developed state and federal regulatory policies to determine if policy expectations realistically match the technological achievement. Current regulatory practices require amelioration of spoil bank impacts upon abandonment of an oil/gas well, but this may not occur...
Parkfield, California, liquefaction prediction (USA)
T.L. Holzer, M.J. Bennett, T. L. Youd, A.T.F. Chen
1988, Bulletin of the Seismological Society of America (78) 385-389
The primary purpose of this short note is to formally record the liquefaction prediction (Holzer et al., 1986) made in connection with this predicted earthquake. In addition, this note serves to alert the seismic engineering community to special instrumentation being installed at the prediction site. The instrumentation will consist of...
Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite
J.J. Morelli, D.M. Hercules, P.C. Lyons, C.A. Palmer, J.D. Fletcher
1988, Mikrochimica Acta (96) 105-118
The variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS). Variations in Ba, Cr, Ga, Sr, Ti, and V concentrations among the coals were determined using the LAMM A-1000 instrument. LAMMS analysis is not...
The giant submarine alika debris slide, Mauna Loa, Hawaii
Peter W. Lipman, William R. Normark, James G. Moore, J. B. Wilson, Christina E. Gutmacher
1988, Journal of Geophysical Research (93) 4279-4299
A 4000‐km2 area of submarine slump and slide deposits along the west flank of Mauna Loa volcano has been mapped with GLORIA side‐scan sonar images, seismic reflection profiles, and new bathymetry. The youngest deposits are two debris avalanche lobes that travelled from their breakaway area near the present shoreline as much...
Distribution of late Cenozoic volcanic vents in the Cascade Range: Volcanic arc segmentation and regional tectonic considerations
M. Guffanti, C.S. Weaver
1988, Journal of Geophysical Research Solid Earth (93) 6513-6529
Spatial, temporal, and compositional distributions of approximately 4000 volcanic vents formed since 16 Ma in Washington, Oregon, northern California, and northwestern Nevada illustrate the evolution of volcanism related to subduction of the Juan de Fuca plate system and extension of the Basin and Range province. Vent data were obtained from...
The influence of diet quality on clutch size and laying pattern in mallards
J.L. Eldridge, Gary L. Krapu
1988, The Auk (105) 102-110
We measured the effect of diet quality on variation in the seasonal pattern of Mallard (Anas platyrhynchos) reproduction. Twenty wild-strain hens, consisting of 10 sibling pairs, were maintained in captivity. One sib of each pair was fed an enriched diet, and the other was fed wheat. The wheat diet resulted...
The seismic radiation from composite models of faulting
J. Boatwright
1988, Bulletin of the Seismological Society of America (78) 489-508
The failure of an asperity, i.e., the dynamic rupture of a small fault area with finite stress drop surrounded by a broken or weak fault area which has no stress drop but which slips after the asperity fails, is proposed as a model for the rupture process of a subevent...
Origin of metaluminous and alkaline volcanic rocks of the Latir volcanic field, northern Rio Grande rift, New Mexico
C.M. Johnson, P. W. Lipman
1988, Contributions to Mineralogy and Petrology (100) 107-128
Volcanic rocks of the Latir volcanic field evolved in an open system by crystal fractionation, magma mixing, and crustal assimilation. Early high-SiO2 rhyolites (28.5 Ma) fractionated from intermediate compositionmagmas that did not reach the surface. Most precaldera lavas have intermediate-compositions, from olivine basaltic-andesite (53% SiO2) to quartz latite (67% SiO2)....
Causes of varied sediment gravity flow types on the Alsek Prodelta, northeast Gulf of Alaska
William C. Schwab, Homa J. Lee, Bruce F. Molnia
1988, Marine Geotechnology (7) 317-342
Slope failures and subsequent mass movements have been identified in Holocene glaciomarine sediment on declivities less than 1.3° on the Alsek prodelta, Gulf of Alaska. Isolated collapse features cover less than 10 percent of a nearshore sand deposit, in water depths less than 40 m. In contrast, sediment gravity flow...
Gravity-induced stresses in stratified rock masses
B. Amadei, H.S. Swolfs, W. Z. Savage
1988, Rock Mechanics and Rock Engineering (21) 1-20
This paper presents closed-form solutions for the stress field induced by gravity in anisotropic and stratified rock masses. These rocks are assumed to be laterally restrained. The rock mass consists of finite mechanical units, each unit being modeled as a homogeneous, transversely isotropic or isotropic linearly elastic material. The following...
Fuelwood production and use in rural Swaziland: a case-study of two communities
J. A. Allen, D.P. Pimentel, J.P. Lasoie
1988, Forest Ecology and Management (25) 239-254
Information of fuelwood consumption and the local production of wood was collected in two small rural communities in Swaziland. Fuelwood consumption was estimated to be 0.77 t persona??1 yeara??1 in one community (Sigombeni), and 0.63 t persona??1 in the other (Bhekinkhosi). Bhekinkhosi was found to be experiencing a significant fuelwood...
Habitat islands and the equilibrium theory of island biogeography: testing some predictions
M. Brown, J.J. Dinsmore
1988, Oecologia (75) 426-429
Species-area data from a study of marsh birds are used to test five predictions generated by the equilibrium theory of island biogeography. Three predictions are supported: we found a significant species-area relationship, a non-zero level of turnover, and a variance-mean ratio of 0.5. One prediction is rejected: the extinction rates...
A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies
P. Switzer, J.W. Harden, R. K. Mark
1988, Mathematical Geology (20) 49-61
A statistical method for estimating rates of soil development in a given region based on calibration from a series of dated soils is used to estimate ages of soils in the same region that are not dated directly. The method is designed specifically to account for sampling procedures and uncertainties...
The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982
W.W. Chadwick Jr., R.J. Archuleta, D. A. Swanson
1988, Journal of Geophysical Research Solid Earth (93) 4351-4366
Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive activity (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating deformation of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending activity....
The Argos seismic data message system
J.S. Derr, R.N. Hunter
1988, Bulletin of the Seismological Society of America (78) 1000-1005
A reliable, inexpensive method for sending limited daily seismic data messages from remote observatories to the National Earthquake Information Center has been developed for use with the Argos satellite system. Data messages are compressed on a microcomputer and passed automatically to a simple transmitter. About 4 hr later, the data...
Air encapsulation during infiltration
Jim Constantz, W.N. Herkelrath, F. Murphy
1988, Soil Science Society of America Journal (52) 10-16
A series of field and laboratory experiments were performed to measure the effects of air encapsulation within the soil's transmission zone upon several infiltration properties. In the field, infiltration rates were measured using a double-cap infiltrometer (DCI), and soil-water contents were measured using time-domain reflectometry (TDR). Before half of the...
HELIOTHERMAL LAKE MODEL OF BORATE DEPOSITION IN THE MIOCENE FURNACE CREEK FORMATION, DEATH VALLEY REGION, CALIFORNIA.
Charles E. Barker, James M. Barker
Grayson S.J.Smith D.A., editor(s)
1988, Conference Paper, Preprint - Society of Mining Engineers of AIME
Heliothermal lakes are density-stratified with shallow submerged margins surrounding areally restricted deep pool(s) containing a dense brine overlain by a much less dense brine. The reflective brine interface allows solar energy to be trapped in the dense brine which may warm to over 90 degree C. Carbonate precipitated from the...
Processes affecting the distribution of selenium in shallow groundwater of agricultural areas, western San Joaquin Valley, California
S. J. Deverel, Roger Fujii
1988, Water Resources Research (24) 516-524
A study was undertaken to evaluate the processes affecting the chemistry of shallow groundwater associated with agricultural drainage systems in the western San Joaquin Valley, California. The study was prompted by a need for an understanding of selenium mobility in areas having high selenium concentrations in shallow groundwater. Groundwater samples...
