Dark Canyon Limestone Deposits, Loraine Mining District, Kern County, California (original) (raw)

LOCATION 30S 34E Sec. 30 and 24 MDM 35.30889 -118.27341 (MRDS, 2011) Sec. 30, T30S,R35E, MDM, and N1/2SE1/4, SW1/4NE1/4, NE1/4SW1/4 Sec. 24; T30S, R4E, MDM, 11 miles east of Loraine at the head of Back Canyon (Troxel and Morton, 1962, p. 233). GEOLOGY White to light gray, fine-to coarse-grained pre-Cretaceous crystalline limestone crops out in several large bodies on both sides of Back Canyon. The limestone contains quartz veins, dolomite zones and graphite flakes and is underlain by granitic rocks and mica schist. In places the limestone is intruded by granitic rocks. See table in text for analysis (Troxel and Morton, 1962, p. 223). Smith (1964, Figures 7 and 8 this report) mapped the area of the Dark Canyon Deposits at confluence of 2 rock types: -Tertiary hypabyssal intrusive rhyolite: Tir -Mesozoic granite gr Lourke (1965) mapped the area of the Dark Canyon Deposits as being at a contact with a mass of “Leucoganite of Back Canyon and Indian Creek (lgr). The leucogranite is glaring white on a fresh surface and weathers to a dull light orange-tan color. It is equigranular, with average grain size of .08 inches, but finer grained toward the margins. The rock is composed or quartz (35-40% ), potassium feldspar (35-40%,), plagioclase (20-30% ), and biotite (10-30%,). Rare local concentrations of biotite take the form of “clots” scattered in the granite and pegmatite veins with abundant quartz and potassium feldspar are widespread. The leucogranite is notable for the lack of any metallic mineralization, either within or at the contact of surrounding rock (Lourke, 1965, p. 14). A strip metasedimentary rock trending northwest-southeast is 750 feet to the southwest of the MRDS mine location.