The Geology of a Portion of the Rand Mountains, California

Citation

Evans, Milton Harrison (1935) The Geology of a Portion of the Rand Mountains, California. Bachelor's thesis, California Institute of Technology. doi:10.7907/CC9G-KC62. https://resolver.caltech.edu/CaltechTHESIS:12142009-151140150

Abstract

The Rand Mountains form a small desert range lying about 150 miles northeast of Los Angeles, and 40 miles east of Mojave, California. The town of Randsburg, in the northeast part of the range, has been the center of considerable mining activity for the past 40 years. Approximately 40 million dollars in gold and silver have been taken from the mines of the district, chiefly from the famous Yellow Aster and California Rand mines. Despite the mining activities, however, practically no geologic work had been done in this district prior to 1924. In 1909, Hess (1) made a brief reconnaissance of the Randsburg district in which he noted the types of rooks in the Rand Mountains, their general structure, and the nature of the ore deposits. Hess' work remained the only significant study until 1924, when Hulin (2), under the direction of the California State Mining Bureau, made a detailed study of the entire Randsburg quadrangle, defining and mapping the formations, and studying the ore deposition in all the important mines of the quadrangle. It seemed to the writer, however, that the unusual rocks of the Rand Mountains merited a more detailed petrographic study than Hulin was able to make, and considerable time was spent during the spring of 1935 in a field and laboratory study of them.

The Randsburg quadrangle lies between 117°30’ and 117°45’ east longitude, and 35°15’ and 35°30’ north latitude. It was surveyed in 1900 by the U. S. Geological Survey on a scale of 1/62500 with a contour interval of 50 feet. The Rand Mountains extend from near the center of the map southwest towards the western border. As a typical section for study, the writer chose a narrow area of about 5 square miles in the immediate vicinity of Randsburg.

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