MLA 55-85 - Mineral Resources Of The Jacumba Study Area, Imperial County, California ? Summary

The study area, which comprises 28,443 acres within the Jacumba Wilderness Study Area, is in the California Desert Conservation Area, and along the U.S.-Mexico border 25 miles west of Fl Centro, CA. The U.S. Bureau of Mines evaluation of mineral resources is based on examination of mining claims, known mineral occurrences, and mineralized zones during the fall of 1983. Limestone resources were identified inside the study area; tungsten resources may he present. Metasedimentary rocks intruded by Cretaceous Quartz diorite predominate in the study area. Tungsten and some gold have been found in skarn zones along intrusive contacts; limestone deposits are in the pre-Cretaceous rocks. Tertiary and Quaternary volcanic flows, pyroclastic rocks, clay beds, and diatomite in lake deposits nave been investigated for possible non-metallic resources. Evidence of mining or prospecting was found at 26 sites in or just outside the study area. In 1983, 106 claims were held in 13 claim groups. One claimant was sporadically prospecting for gold on claims in the north part of the study area in 1983, and gravel was being mined from alluvium 1/4 mile to the east.