Crustal structure of Oaxaca, Mexico, from seismic refraction measurements
C.M. Valdes, Walter D. Mooney, S.K. Singh, C. Lomnitz, James H. Luetgert, C.E. Helsley, B.T.R. Lewis, M. Mena
1986, Bulletin of the Seismological Society of America (76) 547-563
Seismic refraction and gravity data have been analyzed to obtain a model of the compressional-wave velocity structure of the ocean-to-continent transition in the State of Oaxaca in southwestern Mexico. Crustal thickness on the continent at the latitude 18°N is 45 ± 4 km, based on reflected phases from the Moho...
Groundwater transport of strontium 90 in a glacial outwash environment
Kenneth L. Kipp Jr., Kenneth G. Stollenwerk, David B. Grove
1986, Water Resources Research (22) 519-530
As part of the investigation of groundwater contamination at a uranium-scrap recovery plant at Wood River Junction, Rhode Island, laboratory experiments led to the development of a model for predicting the transport of strontium 90 in glacial outwash sediments based on an approximate mechanism for ion exchange. The multicomponent system...
Physiological condition of autumn-banded mallards and its relationship to hunting vulnerability
Gary R. Hepp, Robert J. Blohm, Robert E. Reynolds, James E. Hines, James D. Nichols
1986, Journal of Wildlife Management (50) 177-183
An important topic of waterfowl ecology concerns the relationship between the physiological condition of ducks during the nonbreeding season and fitness, i.e., survival and future reproductive success. We investigated this subject using direct band recovery records of mallards (Anas platyrhynchos) banded in autumn (1 Oct-15 Dec) 1981-83 in the Mississippi...
Sediment transport simulation in an armoured stream
Robert T. Milhous, Jeffrey B. Bradley, Cindy L. Loeffler
1986, Book, Proceedings of the Fourth Federal Interagency Sedimentation Conference
Improved methods of calculating bed material stability and transport must be developed for a gravel bed stream having an armoured surface in order to use the HEC-6 model to examine channel change. Good possibilities exist for use of a two layer model based on the Schoklitsch and the Einstein-Brown...
The application of habitat modeling to the desert tortoise (Gopherus agassizii)
Melvin L. Schamberger, Frederick B. Turner
1986, Herpetologica (42) 134-138
Habitat modeling offers an approach to understanding some management problems of desert tortoises (Gopherus agassizii) and to focusing new research efforts. Modeling can provide (1) a method to organize existing information, (2) a means to identify whether physical habitat or some factor outside the scope of the habitat model...
Modeling contamination of shallow unconfined aquifers through infiltration beds
D.W. Ostendorf
1986, Water Resources Research (22) 375-382
We model the transport of a simply reactive contaminant through an infiltration bed and underlying shallow, one-dimensional, unconfined aquifer with a plane, steeply sloping bottom in the assumed absence of dispersion and downgradient dilution. The effluent discharge and ambient groundwater flow under the infiltration beds are presumed to form a...
Predictive accuracy of a ground-water model--Lessons from a postaudit
Leonard F. Konikow
1986, Groundwater (24) 173-184
Hydrogeologic studies commonly include the development, calibration, and application of a deterministic simulation model. To help assess the value of using such models to make predictions, a postaudit was conducted on a previously studied area in the Salt River and lower Santa Cruz River basins in central Arizona. A deterministic,...
Kovats and lee retention indices determined by gas chromatography/mass spectrometry for organic compounds of environmental interest
Colleen E. Rostad, Wilfred E. Pereira
1986, Journal of Separation Science (9) 328-334
Retention indices of standard organic compounds of environmental interest were determined by gas chromatography/mass spectrometry, using a DB‐5 fused‐silica capillary column. Retention indices are useful references for tentative compound identification by gas chromatography, or confirmation by gas chromatography/mass spectrometry. They provide elution order for isomers that...
Strain accumulation in the Shumagin and Yakataga seismic gaps, Alaska
J.C. Savage, M. Lisowski, W.H. Prescott
1986, Science (231) 585-587
Strain accumulation during the 1980-85 interval has been measured by means of trilateration surveys in the Shumagin and Yakataga seismic gaps, which are the two regions identified as the most likely sites for the next great thrust earthquakes along the Alaska-Aleutian arc. No significant strain accumulation was detected in the...
Depletion of 13C in Cretaceous marine organic matter: Source, diagenetic, or environmental sigal?
Walter E. Dean, Michael A. Arthur, George E. Claypool
1986, Marine Geology (70) 119-157
Geochemical studies of Cretaceous strata rich in organic carbon (OC) from Deep Sea Drilling Project (DSDP) sites and several land sections reveal several consistent relationships among amount of OC, hydrocarbon generating potential of kerogen (measured by pyrolysis as the hydrogen index, HI), and the isotopic composition of the OC. First,...
Identification of solute loading sources to a surface stream
R. L. Rittmaster, D. K. Mueller
1986, Journal of the American Water Resources Association (22) 81-89
A study was performed to identify sources of solute loading to the Dirty Devil River and its major tributaries, in southeastern Utah. A primary goal was to determine the contribution of gypsum dissolution to total dissolved solids concentration, and its potential increase in the future if salinity...
Late Neogene and Quaternary coarse-fraction and carbonate stratigraphies for Site 586 on Ontong-Java Plateau and Site 591 on Lord Howe Rise
J. V. Gardner, Walter E. Dean, Lynne Bisagno, Eileen Hemphill-Haley
1986, Initial Reports of the D.S.D.P. (90) 1020-1124
Carbonate oozes recovered by hydraulic piston coring at DSDP Site 586 on Ontong-Java Plateau and Site 591 on Lord Howe Rise have carbonate contents that are consistently higher than 90% with only minor variations. Consequently, paleoceanographic signals were not recorded in detail in the carbonate contents. However, mass accumulation rates...
Unsteady, nonuniform landslide motion: 1. Theoretical dynamics and the steady datum state
Richard M. Iverson
1986, Journal of Geology (94) 1-15
Unsteady, nonuniform motion of persistently active landslides is a process of widespread importance. A general, three-dimensional theory aimed at elucidating this process is developed from physical principles and field measurements of landslide behavior. The theory employs a versatile constitutive model that represents...
Denning of grizzly bears in the Yellowstone National Park area
Steven L. Judd, Richard R. Knight, Bonnie M. Blanchard
1986, Bears: Their Biology and Management (6) 111-117
Radiotelemetry was used to locate 101 grizzly bear (Ursus arctos) dens from 1975 to 1980; 35 dens were examined on the ground. Pregnant females denned in late October, and most other bears denned by mid-November. Duration of denning average 113, 132, and 170 days for males, females, and...
Origin of the Mariano Lake uranium deposit, McKinley County, New Mexico
Neil S. Fishman, Richard L. Reynolds
1986, Book chapter, A basin analysis case study: The Morrison Formation, Grants Uranium Region, New Mexico
The Mariano Lake uranium deposit, hosted by the Brushy Basin Member of the Jurassic Morrison Formation, occurs in the Smith Lake district of the Grants uranium region, New Mexico. The orebody, contains abundant amorphous organic material, which suggests that it represents a primary-type deposit; however, the orebody is...
Vegetation and soil recovery in wilderness campsites closed to visitor use
Thomas J. Stohlgren, David J. Parsons
1986, Environmental Management (10) 375-380
Recreational use of wilderness results in impacts to vegetation and soil in trails and campsites. Traditionally, campsite impact studies have compared campsites receiving various levels of use with unused control areas. Field studies in Sequoia National Park, California, indicate that the degree of impact to vegetation and soils also varies...
Grizzly bear habitat research in Glacier National Park, Montana
C.J. Martinka, K.C. Kendall
1986, Book, USDA Forest Service General Technical Report Proceedings: Grizzly Bear Habitat Symposium
Grizzly bear habitat research began in 1967 and is continuing in Glacier National Park, MT. Direct observations and fecal analysis revealed a relatively definable pattern of habitat use by the bears. Habitat data were subsequently used to develop management models and explore the relationships between grizzlies and park...
Physio-chemical processes affecting copper, tin and zinc toxicity to algae: A review
James S. Kuwabara
1986, Book chapter, Studies in environmental science
This chapter focuses on the physic-chemical processes affecting copper, zinc, and tin toxicity to algae. Both Cu and Zn are essential algal micronutrients, cofactors in numerous biochemical processes. The availability of a nutrient or toxic substance can be significantly affected by precipitation. Methods for modeling the effects of adsorption–desorption reactions...
Geochronology of augen gneiss and related rocks, Yukon-Tanana terrane, east-central Alaska
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen L. Foster
1986, Geological Society of America Bulletin (97) 626-637
Using several isotopic techniques, we have determined the ages of selected metamorphic rocks in the Yukon-Tanana terrane (YTT) of east-central Alaska. U-Pb zircon data from an augen gneiss body in the Big Delta quadrangle indicate that the granitoid protolith of the gneiss was intruded 341 ± 3 m.y. ago (lower...
Evaluating the structure of habitat for wildlife
H.L. Short, S.C. Williamson
1986, Book chapter, Wildlife 2000: Modeling habitat relationships of terrestrial vertebrates
No abstract available....
Concepts and constraints of habitat model testing
M. Schamberger, J. O'Neil
1986, Book chapter, Wildlife 2000: Modeling habitat relationships of terrestrial vertebrates
No abstract available....
Larval settlement into marine soft-sediment systems: Interactions with the meiofauna
Mary C. Watzin
1986, Journal of Experimental Marine Biology and Ecology (98) 65-113
The distribution and abundance of organisms exhibiting complex life cycles, like marine invertebrates, reflect ecological processes operating at all stages in the life history. Few studies have yet considered the mortality patterns of larvae and juveniles. To test whether the permanent meiofauna play a role in macrofaunal larval site-selection, and/or...
Interannual variability in biochemistry of partially mixed estuaries: Dissolved silicate cycles in northern San Francisco Bay
David H. Peterson, Daniel R. Cayan, John F. Festa
Douglas A. Wolfe, editor(s)
1986, Book chapter, Estuarine variability
Much of the interannual variability in partially mixed estuaries in dissolved inorganic nutrient and dissolved oxygen patterns results from an enhancement or reduction of their annual cycle (generally via climatic forcing). In northern San Francisco Bay estuary the annual cycle of dissolved silicate supply peaks in spring and the effect...
Nd-Sr-Pb isotope constraints on the sources of west Maui volcano, Hawaii
E. Hegner, D. Unruh, M. Tatsumoto
1986, Nature (319) 478-480
The origin of the Emperor-Hawaiian volcanic chain is attributed to the northwesterly movement of the Pacific plate over a stationary mantle plume (hotspot)1. There has been considerable controversy as to the nature and number of sources of Hawaiian hotspot volcanism. Thus far, most geochemical models have been based on rock...
Zimbabweite, a new alkali-lead arsenic tantalate from St Anns mine, Karoi district, Zimbabwe
Eugene E. Foord, Joseph E. Taggart, R. V. Gaines, P. L .C. Grubb, R. Kristiansen
1986, Bulletin de Mineralogie (109) 331-336
Zimbabweite (Na,K)2PbAs4(Ta,Nb,Ti)4O18, a new mineral with trivalent arsenic, has been recognized at St Anns mine, southeast of Miami, Karoi district, Zimbabwe, in kaolinized pegmatite and dump material.The mineral is honey yellow-brown in large crystals, which are as much as 1 x 1 x 2 cm, and is clear pale yellow...
