Publications

Audiomagnetotelluric (AMT) data along four profiles in western Snake Valley and the corresponding two-dimensional (2-D) inverse models reveal subsurface structures that may be significant to ground-water investigations in the area. The AMT method is a valuable tool for estimating the electrical resistivity of the earth over depth ranges from a few meters to less than one kilometer. The method has

How the processes that initiate turbidity currents influence turbidite deposition is poorly understood, and many discussions in the literature rely on concepts that are overly simplistic. Marine geological studies provide information on the initiation and flow path of turbidity currents, including their response to gradient. In case studies of late Quaternary turbidites on the eastern Canadian and

Fossil Chironomidae assemblages (with a few Chaoboridae and Ceratopogonidae) from Zagoskin and Burial Lakes in western Alaska provide quantitative reconstructions of mean July air temperatures for periods of the late-middle Wisconsin (~39,000-34,000 cal yr B.P.) to the present. Inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordina

To provide an improved methodology for characterizing the field‐saturated hydraulic conductivity (Kfs) over broad areas with extreme spatial variability and ordinary limitations of time and resources, we developed and tested a simplified apparatus and procedure, correcting mathematically for the major deficiencies of the simplified implementation. The methodology includes use of a portable, fallin

To assess the eff ect of pedogenesis on the soil moisture dynamics infl uencing the character and quality of ecological habitat, we conducted infi ltration and redistribution experiments on three alluvial deposits in the Mojave National Preserve: (i) recently deposited active wash sediments, (ii) a soil of early Holocene age, and (iii) a highly developed soil of late Pleistocene age. At each, we p

Seven previously unrecognized fusulinid species from Lower Permian (Wolfcampian and Leonardian) turbidites near Conglomerate Mesa in east-central California, four of which are named as new species, are here described and figured. The four new species are Schwagerina merriami, S. wildei, Parafusulina mackevetti, and Skinnerella rossi. These fusulinid species have close affinities to similar taxa in

Among the greatest uncertainties in future energy supply and a subject of considerable environmental concern is the amount of oil and gas yet to be found in the Arctic. By using a probabilistic geology-based methodology, the United States Geological Survey has assessed the area north of the Arctic Circle and concluded that about 30% of the world’s undiscovered gas and 13% of the world’s undiscover

Paleoclimate records play a key role in our understanding of Earth's past and present climate system and in our confidence in predicting future climate changes. Paleoclimate data help to elucidate past and present active mechanisms of climate change by placing the short instrumental record into a longer term context and by permitting models to be tested beyond the limited time that instrumental me

No abstract available.

No abstract available.

Gravity and aeromagnetic data refine the structural setting for the region of western Utah and eastern Nevada between Snake and Hamlin Valleys on the west and Tule Valley on the east. These data are used here as part of a regional analysis. An isostatic gravity map shows large areas underlain by gravity lows, the most prominent of which is a large semi-circular low associated with the Indian Peak

Metropolitan Portland, Oregon, USA, lies within a small Neogene to Holocene basin in the forearc of the Cascadia subduction system. Although the basin owes its existence and structural development to its convergent-margin tectonic setting, the stratigraphic architecture of basin-fill deposits chiefly reflects its physiographic position along the lower reaches of the continental-scale Columbia Rive