Publications

Surface processes accelerated by severe storms during the 1997–1998 El Niño event scoured hillsides and damaged property across coastal California. Technological advances such as digital mapping, exemplified here for the San Francisco Bay area but applicable elsewhere, have enabled government agencies to better describe, monitor, and predict the effects of shoreline erosion and slope...

The Pacific Section, S.E.P.M. 1998 Fall Field Trip will traverse rocks of the Gualala block of northern California. Seven stops (Figure 1) will be made in one and a half days and will examine a variety of geologic features and rock types in this significant area. The field trip is an outgrowth of a symposium held at the 1998 Annual Meeting of the Pacific Section, S.E.P.M. in Ventura...

This report describes a digital map and data files generated by the U.S. Geological Survey (USGS) to provide digital spatial mining claim information for Federal lands in Montana as of March, 1997. Statewide, 159,704 claims had been recorded with the Bureau of Land Management since 1975. Of those claims, 21,055 (13%) are still actively held while 138,649 (87%) are closed and are no...

MORPH-I is a set of C-language computer programs for the IBM PC and compatible minicomputers. The programs in MORPH-I are used for the fractal analysis of scanning electron microscope and electron microprobe images of pore profiles exposed in cross-section. The program isolates and traces the cross-sectional profiles of exposed pores and computes the Richardson fractal dimension for each...

The Payette National Forest (PNF), in west-central Idaho, is geologically diverse and contains a wide variety of mineral resources. Mineral deposit types are grouped into locatable, leasable, and salable categories. The PNF has substantial past production and identified resources of locatable commodities, including gold, silver, copper, zinc, tungsten, antimony, mercury, and opal. Minor...

This report presents porewater and selected water column data collected from Coeur d'Alene Lake in September of 1992. Despite probable oxidation of the porewater samples during collection and handling, these data are used to calculate molecular diffusive fluxes of dissolved metals (that is, Zn, Pb, Cu, and Mn) across the sediment-water interface. While these data and calculations provide

This map database represents the integration of previously published and unpublished maps by several workers (see Sources of Data index map on Sheet 2 and the corresponding table below) and new geologic mapping and field checking by the authors with the previously published geologic map of San Mateo County (Brabb and Pampeyan, 1983) and Santa Cruz County (Brabb, 1989, Brabb and others...

The confidence parameters in Table 5 and Figures 7 -12 in Bakun and Wentworth (1997) were calculated using the site corrections for MI(4) rather than Bakun and Wentworth's (1997) preferred relation MI(3). The conclusions of Bakun and Wentworth (1997) are not changed by these corrections. The corrected Table 5 and Figures are in this report and at http://quake.wr.usgs.gov/~bakun/.

The purpose of this report is to show graphically how the Klamath Mountains grew from a relatively small nucleus in Early Devonian time to its present size while rotating clockwise approximately 110°. This growth occurred by the addition of large tectonic slices of oceanic lithosphere, volcanic arcs, and melange during a sequence of accretionary episodes. The Klamath Mountains province...

Computer programs were written in the Fortran language to process and display gravity data with locations expressed in geographic coordinates. The programs and associated processes have been tested for gravity data in an area of about 125,000 square kilometers in northwest Nevada, southeast Oregon, and northeast California. This report discusses the geographic aspects of data processing

The U.S. Geological Survey has two international and one regional digital database that contains information on mineral properties. This report describes the conversion of selected data from one of the international databases - MAS/MILS (Mineral Availability System/Mineral Industry Location System) - into a spatial data product. The MAS/MILS database, obtained from the U.S. Bureau of...

Field and laboratory investigations of the giant Betze gold orebody, the largest Carlin-type deposit known, in the north-central Carlin trend, Nevada document that the orebody is composed of individual high-grade oreshoots that contain different geologic, mineralogic, and textural characteristics. The orebody is typical of many structurally controlled Carlin-type deposits, and is hosted...