Publications

The USGS has undertaken a first order evaluation of sand & gravel resources in the Lower Boise River Valley in response to rapid urban expansion in the Boise-Nampa-Caldwell corridor in southwest Idaho. The study is intended to provide land-use planners and managers, particularly in the Bureau of Land Management, with a foundation of knowledge that will allow them to anticipate and plan for demand

Version 1.1 of this Open-File Report contains a digital geologic map and map database of the Fawnskin 7.5' quadrangle, San Bernardino County, California, that includes: 1. ARC/INFO (Environmental Systems Research Institute) version 7.2.1 double-precision coverages of the various elements of the geologic map 2. A PostScript (.ps) file to plot the geologic map on a topographic base, containing a Co

Material inventories for prospective sources of material for use in building roads and associated structures were prepared by Arizona for several counties including Maricopa County. The inventories provide information about pit locations, materials classification and type, and measures of some characteristics used to determine suitability for aggregate. The digital data given in this release was

The Dixonville 7.5 minute quadrangle is situated near the edge of two major geologic and tectonic provinces the northernmost Klamath Mountains and the southeastern part of the Oregon Coast Ranges (Figure 1). Rocks of the Klamath Mountains province that lie within the study area include ultramafic, mafic, intermediate and siliceous igneous types (Diller, 1898, Ramp, 1972, Ryberg, 1984). Similar roc

The Parkfield mercury district is located in the southern part of the California Coast Range mercury mineral belt and contains three silica-carbonate-type mercury deposits that have had significant mercury production. Mercury was first produced in the district in 1873, but the main period of production occurred from 1915-1922. Total production from the district is about 5,000 flasks of mercury (a

Gravity and magnetic surveys were performed along the western flanks of the Santa Rita Mountain range located in southeastern Arizona to develop an understanding of the relationship between surface fault scarps within the basin fill sediments and theirgeophysical response of the faults at depth within the bedrock. Data were acquired for three profiles, one of them along the northern terrace of Mon

The geologic map of the Tucson-Nogales 1:250,000 scale quadrangle (Peterson and others, 1990) was digitized by U.S. Geological Survey staff and University of Arizona contractors at the Southwest Field Office, Tucson, Arizona, in 2000 for input into a geographic information system (GIS). The database was created for use as a basemap in a decision support system designed by the National Industrial M

We present an apatite fission-track (AFT) study of five plutonic rocks and seven metamorphic rocks across 310 km of the Yukon–Tanana Upland in east-central Alaska. Samples yielding ~40 Ma AFT ages and mean confined track lengths > 14 µm with low standard deviations cooled rapidly from >120°C to <50°C during a 3–5 Ma period, beginning at about 40 Ma. Data from samples yielding AFT ages >40 Ma sugge

No abstract available.

No abstract available.

The Western Earth Surfaces Processes Team (WESPT) 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

Gravity and magnetic data provide new insights on the structural underpinnings of the San Fernando Basin region, which may be important to ground motion models. Gravity data indicate that a deep basin (>5 km) underlies the northern part of the San Fernando Valley; this deep basin is required to explain the lowest gravity values over the Mission Hills thrust fault. Gravity modeling, constrained by