Publications

Field observations, sampling of mine dumps and mine drainage waters, and laboratory studies of dump materials have been made at mining areas deemed to be on public lands administered by the USDA Forest Service in the Mineral Creek watershed. Results of chemical analyses of dump materials, leachates of those materials, and of surface waters draining mines or dumps provide indications of...

This geologic map was prepared as a part of a study of digital methods and techniques as applied to complex geologic maps. The geologic map was digitized from the original scribe sheets used to prepare the published Geologic Map of Colorado (Tweto 1979). Consequently the digital version is at 1:500,000 scale using the Lambert Conformal Conic map projection

No abstract available.

The geology of the Payette National Forest and vicinity, Idaho (Fig. 1), was mapped and compiled by Karen Lund between 1992 and 1996. The geologic data for the digital map are from original mapping as well as compilation by Lund of numerous sources of published and unpublished geologic maps that are cited in the section 'Bibliography of Geologic Map Sources.' The geology was compiled...

Methane hydrates are ice‐like inclusion compounds, in which every volume of hydrate can contain as much as 180 volumes (STP) of gas.The amount of methane in natural gas hydrates is twice the total recoverable fossil fuel reserve. Because of their natural abundance in oceans and permafrost, hydrates have become an exciting national and international research issue. The movement of the gas...

Potassium has three isotopes (see Potassium); potassium-40 ( 40K) is radioactive and decays to both calcium-40 ( 40Ca) and argon-40 ( 40Ar). The combined half-life of 40K is 1.25 billion years. The branched decay scheme of 40K is shown in Figure P33. It decays by β- decay to 40Ca and to 40Ar by both electron capture and positron decay (see Potassium-argon decay system). Although 89.52%...

One of the greatest contributions of geochemistry to man's knowledge of the Earth and solar system has been the development and application of chemical and isotopic techniques used to measure the passage of time. Rates of geologic processes, rates of biological evolution, and contemporaneity of past events all depend on accurate ages of geologic materials. Many geochemical methods have...

No abstract available.

No abstract available.

Co-occuring conodonts, radiolarians, and sponge spicules from the type locality of the Slaven Chert, northern Shoshone Range, Nevada, indicate that the radiolarian and sponge spicule assemblage described herein correlates with the Late rhenana conodont Zone (late Frasnian). The moderately well preserved radiolarians are the first Frasnian-age fauna described from the Western Hemisphere...

Distinguishing Grenvillian basement rocks from pre-Taconian cover sequences in the Appalachians is a first-order problem essential for accurate structural interpretations. The Cavendish Formation in southeastern Vermont presents a classic example of this problem. Doll and others (1961) showed the Cavendish Formation as younger than the Middle Proterozoic Mount Holly Complex but older...

No abstract available.