Publications

Lithic specimens identified as artifacts have been recovered from near the base of the Yermo fan deposits at Calico, California. The soil on the fan surface is a strongly developed relict paleosol. Comparison of this soil with dated paleosols elsewhere in the southwestern United States suggests that the surface is about 80,000 to 125,000 yr old. Clasts near the base of the deposit are...

Core recovered from Hess Rise contains concentrations of pyrite, marcasite, and barite in the lowermost meter of limestone (Unit II) and in the brecciated upper part of the underlying volcanic basement (Unit HI). Petrographic and chemical data indicate that the sulfide-barite assemblage in the limestone is mainly a product of low-temperature diagenetic processes. The iron-sulfide phases...

Determining geologic ages of fossils by amino acid racemization techniques is often difficult because of the uncertainties in assumptions about diagenetic temperatures. Two kinetic model methods have been employed. Method 1, used by us, assumes that racemization of amino acids in the bivalve mollusk Saxidomus giganteus from Willapa Bay, Washington, follows linear kinetics. Ages are...

By studying the geochemistry of amino acids, we attempt to clarify uncertainties in the radiocarbon chronology and in correlations of ash beds and pollen spectra in lacustrine sediment from Clear Lake, California. Two amino acids, aspartic acid and alanine, are considered in detail. Relative concentrations of aspartic acid decrease with depth, a result likely due to diagenesis and to...

Thermally produced hydrocarbons were recovered from unconsolidated sediment ponded within a bathymetric depression on the surface of a shale diapir in the offshore Eel River Basin of northern California. Evidence that the hydrocarbons are thermogenic consists of the following: (1) very high concentrations of hydrocarbon gases, particularly ethane through butanes (C2-C4); (2) methane...

Since the beginning of the Deep Sea Drilling Project DSDP in 1968 and extending through 1975 organic geochemical studies have been undertaken on about 2300 samples recovered on Legs I through 44 from sediments beneath the ocean floors These studies have provided fundamental information regarding the distribution of carbon in oceanic sediments and have yielded a better understanding of...

Bowers Ridge is a large, arcuate sub-marine ridge that extends north and west from the Aleutian Ridge and separates the abyssal Aleutian and Bowers Basins in the Bering Sea. Two multichannel seismic-reflection lines recorded in 1976 over Bowers Ridge and the adjacent basins confirm the existence of 8- to 10-km-thick sediment wedges on the north side of Bowers Ridge and at the base of the...

Three major bathymetric features exist in the Bering Sea: Shirshov Ridge, Bowers Ridge, and Umnak Plateau. New refraction data over Umnak Plateau and previous geophysical data across Bowers Ridge indicate that a thickened welt of crustal material is present beneath both features. The crustal structure is transitional between oceanic and continental types. Various models for the origin of...

The Continental Margin Sediment Dynamics program of the U.S. Geological Survey has been using a variety of optical instruments to monitor water turbidity as part of our studies of sediment transport. Although we suspect that optical devices will eventually be supplanted by more direct measures of suspended sediments, results of several field experiments indicate that for now...

The Yukon prodelta is exposed to large storm waves propagating northward from the southern Bering Sea. Shallow water depths of the prodelta enhance the transfer of energy from the surface waves to the bottom. As the bottom deposits are cyclically loaded by large storm waves, potential decrease in their resistance to shear could ultimately cause liquefaction. A preliminary assessment of...

No abstract available.

No abstract available.