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U.S. Geological Survey
Open-File Report 2006-1090

Preliminary Surficial Geologic Map of a Calico Mountains Piedmont and Part of Coyote Lake, Mojave Desert, San Bernardino County, California

By Stephanie L. Dudash


thumbnail view of map sheet

This 1:24,000 scale detailed surficial geologic map and digital database of a Calico Mountains piedmont and part of Coyote Lake in south-central California depicts surficial deposits and generalized bedrock units. The mapping is part of a USGS project to investigate the spatial distribution of deposits linked to changes in climate, to provide framework geology for land use management (, to understand the Quaternary tectonic history of the Mojave Desert, and to provide additional information on the history of Lake Manix, of which Coyote Lake is a sub-basin. Mapping is displayed on parts of four USGS 7.5 minute series topographic maps. The map area lies in the central Mojave Desert of California, northeast of Barstow, Calif. and south of Fort Irwin, Calif. and covers 258 km2 (99.5 mi2). Geologic deposits in the area consist of Paleozoic metamorphic rocks, Mesozoic plutonic rocks, Miocene volcanic rocks, Pliocene-Pleistocene basin fill, and Quaternary surficial deposits. McCulloh (1960, 1965) conducted bedrock mapping and a generalized version of his maps are compiled into this map. McCulloh’s maps contain many bedrock structures within the Calico Mountains that are not shown on the present map.

This study resulted in several new findings, including the discovery of previously unrecognized faults, one of which is the Tin Can Alley fault. The north-striking Tin Can Alley fault is part of the Paradise fault zone (Miller and others, 2005), a potentially important feature for studying neo-tectonic strain in the Mojave Desert. Additionally, many Anodonta shells were collected in Coyote Lake lacustrine sediments for radiocarbon dating. Preliminary results support some of Meek’s (1999) conclusions on the timing of Mojave River inflow into the Coyote Basin.

The database includes information on geologic deposits, samples, and geochronology. The database is distributed in three parts: spatial map-based data, documentation, and printable map graphics of the database. Spatial data are distributed as an ArcInfo personal geodatabase, or as tabular data in the form of Microsoft Access Database (MDB) or dBase Format (DBF) file formats. Documentation includes this file, which provides a discussion of the surficial geology and describes the format and content of the map data, and Federal Geographic Data Committee (FGDC) metadata for the spatial map information. Map graphics files are distributed as Postscript and Adobe Acrobat Portable Document Format (PDF) files, and are appropriate for representing a view of the spatial database at the mapped scale.

Download the map sheet as a 52" x 31" PDF file (Plot_file/of06-1090_3a.pdf; 24.8 MB)

Download the accompanying pamphlet as a 48-page PDF file (Documentation/of06-1090_pamphlet.pdf; 3.4 MB)

View the readme file for the digital files as an ASCII text file (Documentation/Readme_of06-1090.txt; 5 pages, 64 KB)

Download database as a .zip file (; compressed file containing 39 items; 3.3 MB compressed, 10.7 MB unzipped)

Browse the documentation folder (13 items; 113.1 MB total)

For questions about the content of this report, contact Stephanie Dudash

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Maintained by: Michael Diggles
Date created: April 24, 2006
Last modified: April 27, 2006 (mfd)