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Mineral resources of the Sawtooth Mountains and Carrizo Gorge/Eastern McCain Valley Wilderness Study Areas, San Diego County, California
| Content Provider | Semantic Scholar |
|---|---|
| Author | Todd, Victoria R. Kilburn, James E. Detra, David E. Griscom, Andrew Knepper, Daniel H. Kruse, Fred A. Cather, Eric E. Lipton, David A. |
| Copyright Year | 1987 |
| Abstract | This report presents the results of mineral surveys of part of the Sawtooth Mountains (CA-060024B) Wilderness Study Area and all of the Carrizo Gorge/Eastern McCain Valley (CA-060-025A) Wilderness Study Area. In this report, the areas studied are referred to as "the wilderness study areas", or simply "the study areas." The Sawtooth Mountains and Carrizo Gorge/Eastern McCain Valley study areas encompass approximately 24,696 and 14,573 acres, respectively, in eastern San Diego County, California. Field work for this report was carried out during 1983 and 1984. No mineral resources or resource potential have been identified in the Sawtooth Mountains Wilderness Study Area. The study area contains extensive sand and gravel occurrences, but these occurrences are not considered resources because similar ones are present closer to population centers such as San Diego and El Centro. The Carrizo Gorge/Eastern McCain Valley Wilderness Study Area has moderate potential for resources of undiscovered gem-grade minerals (kunzite, aquamarine) in pegmatite dikes in the vicinity of Mount Tule in the western part of the study area. No oil, gas, coal, or geothermal resources were identified in either of the study areas. Character and Setting The Sawtooth Mountains and Carrizo Gorge/Eastern McCain Valley Wilderness Study Areas have been combined into a single report because they are geographically close and have similar geologic settings. The Sawtooth Mountains and Carrizo Gorge/Eastern McCain Valley Wilderness Study Areas occupy approximately 24,696 and 14,573 acres, respectively, in eastern San Diego County, Calif. They are located about 40 and 50 mi east of San Diego, respectively (fig. 1). The study areas lie within a transitional physiographic zone between the Peninsular Range province, the mountainous spine of Alta and Baja California to the west, and the Colorado Desert to the east. This zone is characterized by rugged topography and has a semiarid to arid climate. Conifer forests occupy the higher mountain ridges, and chapparal-desert plant communities are found at lower elevations. Topographic relief in the study areas ranges from about 3,800 to 4,100 ft. The Sawtooth Mountains and Carrizo Gorge/Eastern McCain Valley Wilderness Study Areas are underlain by Cretaceous (63 to 138 million years before present (Ma); see appendix for geologic time scale) plutonic rocks of the Peninsular Ranges batholith that form much of the crystalline bedrock of the Peninsular Ranges. The batholith is composed of a variety of deformed Early Cretaceous plutons that were intruded by relatively undeformed younger Cretaceous plutons. These plutons intruded metamorphosed Paleozoic (240 to 570 Ma) and Mesozoic (63 to 240 Ma) sedimentary and volcanic rocks, remnants of which are exposed as steeply dipping tabular bodies, or screens, between the plutons. Patches of Cenozoic (63 Ma to present) alluvial deposits unconformably overlie the uplifted and deeply eroded batholith in both study areas. Faults of various ages cut the batholithic rocks. In the Sawtooth Mountains Wilderness Study Area, some faults cut Quaternary alluvium. Small gold deposits are found in metasedimentary rocks in the Deer Park and Laguna Mountains mining districts, about 4 mi west of the Sawtooth Mountains Wilderness Study Area. There is no record of mining activity in similar metasedimentary rocks within the study area, and no gold or other mineral |
| File Format | PDF HTM / HTML |
| DOI | 10.3133/b1711B |
| Alternate Webpage(s) | https://pubs.usgs.gov/bul/1711b/report.pdf |
| Alternate Webpage(s) | https://doi.org/10.3133/b1711B |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
