By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Gold was discovered in Kern County in 1851 in Greenhorn Gulch, near the Kern River, by a member of General Fremont's party. Mining began in 1852 at the Keyes and Mammoth mines in the Keyes district. From 1880 through 1959 about 1,777,000 ounces of gold was mined, mostly from lode deposits. The major districts are the Amalie, Cove, Green Mountain, Keyes, Rand, and Rosamond-Mojave.
The Amalie district is between, the south summits of the Piute Mountains and Caliente Creek in T. 30 S., Rs. 33 and 34 E. The principal mine, the Amalie, produced $600,000 in gold through 1932 (Tucker and Sampson, 1933, p. 280-281). Total production of the district through 1959 was about 30,000 ounces; nearly all production was from lode mines.
The country rock is dominantly granitic and contains narrow belts of schist and slate. Most of the veins are found in quartz porphyry.
The Cove district is 45 miles northeast of Bakers-field near Kernville, in T. 25 S., R. 33 E.
In the late 1850's a few placers were worked in the Cove district by the more persistent of the prospectors drawn to the area by the original discoveries in Kern County, along the Kern River, in 1851. Gold-bearing quartz veins were found in 1860. The towns of Quartzburg and Kernville, which were founded in the boom that followed, experienced a period of orderly growth and prosperity.
The Big Blue mine of Kern Mines, Inc., was discovered early in the history of the district. The mine became the major producer and was credited with $1,746,910 in gold to 1933 (Tucker and others, 1949, p. 211); most of this production was in the first few years of the mine's activity. In 1883 most of the workings were destroyed by fire, and the mine was inactive until 1907 when the first of several unsuccessful attempts was made to rehabilitate the property.
Total gold production of the district through 1959 was about 262,800 ounces; none had been reported since 1942.
The country rock consists of metasediments, phyllites, quartzites, and limestone of the Kernville Series of Carboniferous (?) age, and the Isabella Granodiorite and acidic dikes of Jurassic (?) age. The granodiorite is probably related to the main Sierra Nevada batholith (Prout, 1940, p. 385-389; Miller and Webb, 1940, p. 378).
The metamorphic rocks are intensely deformed and crumpled by the intrusive rock. Along the east edge of the Cove district is the north-trending Kern Canyon fault, the major structure in the area.
Ore deposits consist of veins which seem to be related to the closing stages of igneous activity. The veins occur in shear zones, parallel to the Kern Canyon fault, and are associated with acidic dikes that cut the granodiorite and metasediments (Prout, 1940, p. 386, 391-392). The veins are dominantly quartz with small amounts of calcite. The ore minerals are gold, which occurs in the free state, arsenopyrite, galena, and sphalerite (Prout, 1940, p. 411-412).
GREEN MOUNTAIN DISTRICT
The Green Mountain district includes the area between Piute, on the west slope of the Piute Mountains, and the edge of Kelsey Valley, on the east side of the Piute Mountains.
Gold production of this district through 1959 was about 33,100 ounces. The Bright Star mine was the major producer, with an estimated $600,000 total output (Tucker and Sampson, 1933, p. 280).
Bedrock in the area consists of metasedimentary rocks of the Kernville Series of Carboniferous (?) age and Isabella Granodiorite of Jurassic (?) age (Miller and Webb, 1940, p. 349-358). The metasedimentary rocks occur in northwest-trending bands and include marble, phyllite, mica schist, and quartzite. The gold deposits are in small, but rich, shoots in narrow quartz veins.
The Keyes district, 35 miles north of Caliente in T. 26 S., Rs. 32 and 33 E., produced about 39,600 ounces of gold through 1959, all from lodes.
Detailed accounts of the history and geology of this district were not found; however, Tucker and Sampson (1933, p. 283) reported that the deposits in the district are in narrow high-grade veins in granite.
The Rand district is on the San Bernardino-Kern County line. Randsburg, 45 miles northeast of Mojave, is in the center of the district. Although more than half the area is in San Bernardino County, nearly all the gold mined in the district has come from the western part, in Kern County. This is the most important district in Kern County, and it contains the largest gold mine in the county, the Yellow Aster. Gold has been the chief commodity mined; silver has been a byproduct.
Placer gold was discovered in the winter of 1893-94 at Goler Wash, 9 miles northwest of Randsburg, and by 1895 the lode deposits of the Yellow Aster mine were developed (Hess, 1910, p. 31-32). Of the estimated $9 to $10 million worth of ore mined before 1910, the Yellow Aster produced $6 million (Hess, 1910, p. 32).
Tucker and Sampson (1933, p. 285-286) gave estimates of the production and a brief account of the geology. Gold production through 1959 was 836,300 ounces, all but about 1,700 ounces was from lode mines.
The country rock in the gold-producing part of the district consists of the Rand Schist and the Atolia Quartz Monzonite which intruded the schist. Numerous rhyolite pipes, dikes, and sills of late Miocene age are found locally. Gold ores occur in fissure veins and as impregnations and stockworks in both the monzonite and Rand schist. The strongest veins have been found to be in two systems - one strikes N. 80° E. and the other, northwest.
The principal vein minerals are quartz, arsenopyrite, pyrite, galena, gold, scheelite, iron oxides, and calcite. Only the oxidized parts of the veins have been mined.
The Rosamond-Mojave district is 4 miles southwest of Mojave, in Tps. 10 and 11 N., Rs. 11, 12, and 13 W. Production from this district, all from lode mines, to about 1933 was about $3.5 million in gold and silver, and gold was apparently the major commodity. This includes production from the Tropico mines, which are a short distance outside the district (Tucker and Sampson, 1933, p. 280-284). Total gold production through 1959 was about 278,250 ounces.
Granite, the oldest rock in the district, is overlain by rhyolite porphyry, which is well exposed throughout the area. The rhyolite porphyry is overlain by sheets and remnants of rhyolite (Tucker and Sampson, 1933, p. 283). Gold deposits are in steeply dipping quartz veins in the rhyolite porphyry that seem to flatten at depth and then follow the porphyry-granite contact.
The veinfilling consists of quartz, granite fragments, calcite, ferruginous clay, and manganese (Tucker and Sampson, 1933, p. 284). Native gold occurs in association with pyrite, chalcopyrite, and minor amounts of galena, marcasite, and sphalerite. The silver minerals are cerargyrite and argentite (Tucker and Sampson, 1933, p, 284).
Several additional gold-producing localities in Kern County were listed by Tucker and Sampson (1933, p. 280). These are the Joe Walker mine, 7 miles northwest of Piute in T. 29 S., R. 33 E., with a production valued at $600,000; the St. John mine, 16 miles south of Weldon in T. 28 S., R. 35 E., with a production worth $700,000; and the Pine Tree mine in T. 11 N., R. 15 W., which produced $250,000 worth of gold.
The Pioneer district, mentioned by Tucker and Sampson (1933, p. 280) as having produced $500,000 in gold, could not be located, and no additional data on this district were found in the literature.
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