Publications

Between 1961 and 1969, Alan Griggs and others conducted fieldwork to prepare a geologic map of the Spokane 1:250,000 map (Griggs, 1973). Their field observations were posted on paper copies of 15-minute quadrangle maps. In 1999, the USGS contracted with the Idaho Geological Survey to prepare a digital version of the Coeur d’Alene 1:100,000 quadrangle. To facilitate this work, the USGS...

In April 2000 the U.S. Geological Survey (USGS) established 211 gravity stations in the Antelope Valley and Bedell Flat area of west-central Nevada (see figure 1). The stations were located about 15 miles north of Reno, Nevada, southwest of Dogskin Mountain, and east of Petersen Mountain, concentrated in Antelope Valley and Bedell Flat (figure 2). The ranges in this area primarily...

This report describes a digital geologic GIS database in an Arc/Info format for the “Geologic Map of Arizona” by Wilson and others (1983 edition).

This geologic map database for the El Mirage Lake area describes geologic materials for the dry lake, parts of the adjacent Shadow Mountains and Adobe Mountain, and much of the piedmont extending south from the lake upward toward the San Gabriel Mountains. This area lies within the western Mojave Desert of San Bernardino and Los Angeles Counties, southeastern California. The area is...

This report presents a preliminary map and database of Quaternary deposits and liquefaction susceptibility for the nine-county San Francisco Bay region, together with a digital compendium of ground effects associated with past earthquakes in the region. The report consists of (1) a spatial database of fivedata layers (Quaternary deposits, quadrangle index, and three ground effects layers...

Turcotte, 1997, and Barton and La Pointe, 1995, have identified many potential uses for the fractal dimension in physicochemical models of surface properties. The image-analysis program described in this report is an extension of the program set MORPH-I (Mossotti and others, 1998), which provided the fractal analysis of electron-microscope images of pore profiles (Mossotti and Eldeeb...

Extensive reconnaissance assessments of the mineral resource potential of the Colville and Okanogan National Forests in northeastern Washington were conducted during 1979-1982 by a private consultant A.R. Grant, under contract with the U.S. Department of Agriculture, Forest Service. These forests occupy large parts of Pend Oreille, Stevens, Ferry, and Okanogan counties, and smaller parts...

The need to integrate large quantities of digital geoscience information to classify locations as mineral deposits or nondeposits has been met by the weights-of-evidence method in many situations. Widespread selection of this method may be more the result of its ease of use and interpretation rather than comparisons with alternative methods. A comparison of the weights-of-evidence method...

A broad west-to-east increase of many metal concentrations has been found in stream sediments during a reconnaissance investigation conducted in conjunction with geologic studies in the Santa Renia Fields and Beaver Peak 7–1/2 minute quadrangles near the northern end of the Carlin trend of gold deposits in the Tuscarora Mountains. This regional increase in metal concentrations coincides...

Regional gravity and aeromagnetic maps reveal the existence of deep basins underlying much of the southwestern Nevada volcanic field, approximately 150 km northwest of Las Vegas. These maps also indicate the presence of prominent features (geophysical lineaments) within and beneath the basin fill. Detailed gravity surveys were conducted in order to characterize the nature of the basin...

No abstract available.

The Western Geologic Mapping Team (WGMT) of the U.S. Geological Survey, Geologic Division (USGS, GD), conducts geologic mapping and related topical earth-science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, potential...