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Open-File Report 00-222

Geologic Map Database of the El Mirage Lake Area, San Bernardino and Los Angeles Counties, California

By David M. Miller and David R. Bedford

Digital preparation by D.R. Bedford

Thumbnail of and link to report PDF (3.74 MB)Introduction

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 traversed by a few paved highways that service the community of El Mirage, and by numerous dirt roads that lead to outlying properties. An off-highway vehicle area established by the Bureau of Land Management encompasses the dry lake and much of the land north and east of the lake. The physiography of the area consists of the dry lake, flanking mud and sand flats and alluvial piedmonts, and a few sharp craggy mountains.

This digital geologic map database, intended for use at 1:24,000-scale, describes and portrays the rock units and surficial deposits of the El Mirage Lake area. The map database was prepared to aid in a water-resource assessment of the area by providing surface geologic information with which deepergroundwater-bearing units may be understood. The area mapped covers the Shadow Mountains SE and parts of the Shadow Mountains, Adobe Mountain, and El Mirage 7.5-minute quadrangles. The map includes detailed geology of surface and bedrock deposits, which represent a significant update from previous bedrock geologic maps by Dibblee (1960) and Troxel and Gunderson (1970), and the surficial geologic map of Ponti and Burke (1980); it incorporates a fringe of the detailed bedrock mapping in the Shadow Mountains by Martin (1992). The map data were assembled as a digital database using ARC/INFO to enable wider applications than traditional paper-product geologic maps and to provide for efficient meshing with other digital data bases prepared by the U.S. Geological Survey's Southern California Areal Mapping Project.

First posted January 10, 2001

Readme's and Metadata

Data and Explanation of Database (the open-file text explains the database)

Files for Viewing and Plotting

Visit theĀ GeoScience Node of the National Spatial Data Clearinghouse to find other geologic-map datasets in southern California or elsewhere in the Nation.

For additional information, contact:
Geology, Minerals, Energy, and Geophysics Science Center
U.S. Geological Survey
345 Middlefield Road, MS 901
Menlo Park, CA 94025-3591
http://geomaps.wr.usgs.gov/gmeg/

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Suggested citation:

Miller, David M., and Bedford, David R., 2000, Geologic Map Database of the El Mirage Lake Area, San Bernardino and Los Angeles Counties, California: U.S. Geological Survey Open-File Report 00-222, https://pubs.usgs.gov/of/2000/0222/.



 


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