link to main US Geological Survey website
125 Years of Science for America - 1879 to 2004
U.S. Geological Survey
Scientific Investigations Map 2851

Geologic Map of the Cerro Gordo Peak 7.5' Quadrangle, Inyo County, California

By Paul Stone, George C. Dunne, James E. Conrad, Brian J. Swanson, Calvin H. Stevens, and Zenon C. Valin


thumbnail sketch of the map

The Cerro Gordo Peak quadrangle encompasses part of the southern Inyo Mountains about 25 km east of Lone Pine, California. This area is of interest for its locally intense and historically important mineralization and its exposures of rocks and structural features that are important for reconstructing the geologic history and tectonic evolution of east-central California. The geologic map presented here depicts our current understanding of the complex stratigraphy and structure of this area.

The Cerro Gordo Peak quadrangle is underlain in large part by sedimentary rocks of Ordovician to Triassic age. These strata accumulated on the western continental margin of North America. Ordovician to Early Mississippian strata in the quadrangle are mostly shallow-water marine carbonate rocks that record sedimentation on the continental shelf. By contrast, the overlying Late Mississippian to Triassic strata represent a variety of deep-water marine, shallow-water marine, and nonmarine depositional settings that reflect episodic tectonism along the continental margin. Sedimentation in the quadrangle was accompanied by Early Permian contractional deformation, Late Permian extensional deformation, and a second episode of contractional deformation in latest Permian time. These deformational events are represented by faults, folds, and unconformities exposed in the quadrangle and other nearby areas.

The Jurassic was marked by the spread of volcanic and volcanogenic strata derived from the southwest. This volcanism marked one growth phase of the Sierran magmatic arc, the core of which lay west of the quadrangle. Intrusive outliers of the arc (dikes, sills, and plutons) sporadically invaded the southern Inyo Mountains region during the Jurassic and Cretaceous. Contractional deformation of the East Sierran Thrust System produced northwest-trending thrust faults, folds with accompanying cleavage, general ductile flattening, and conjugate strike-slip faults in the quadrangle primarily during the Late Jurassic.

The Inyo Mountains and the adjacent bounding valleys are the result of late Cenozoic extensional faulting. In the Cerro Gordo Peak quadrangle, early phases of uplift of the Inyo Mountains are marked by middle to late Miocene fanglomerates on both sides of the range. The fanglomerate on the east side of the range overlaps a major zone of normal faulting (Eastern Inyo Fault Zone). More recent deformation is indicated by normal faults that cut the fanglomerates. Northwest-directed extensional tectonism continues in the region today.



File Name
File Type and Description
File Size
Text-only readme file that explains how to use the digital database
8 Kb
geologic map database files and associated files
596 KB
Federal Geographic Data Committee (FGDC) compliant metadata file derived from the digital database
64 KB
A Portable Document Format (PDF) file for viewing and plotting the geologic map at full scale. The plot is approximately 36 x 42 inches in size.
16.7 MB
A 17-page Portable Document Format (PDF) file for viewing and printing a pamphlet that accompanies the map. The pamphlet contains a geologic interpretation and the description of map units.
2.5 MB

For questions about the content of this report, contact Paul Stone

Download a current version of Acrobat Reader for free

| Help | PDF help | Western reports main page | Western Scientific Investigations Maps |
| Privacy Statement | Disclaimer | Accessibility |
| Geologic Division | Earth Surface Processes |

This report is available via print on demand.

This report is also available from:

USGS Information Services, Box 25286,
Federal Center, Denver, CO 80225
telephone: 303-202-4210; e-mail:

| Department of the Interior | U.S. Geological Survey |
URL of this page:
Maintained by: Michael Diggles
Date created: September 10, 2004
Last modified: October 13, 2006 (mfd)