Geology of the Cache Creek region, Kern County, California: Supplement 1 from "The geology of the Cache Creek region, Kern County, California" (Thesis)

Along the north side of Tehachapi Pass, California, lies a basin containing three Tertiary formations resting on crystalline rocks of Sierra Batholith (?) age. The lowermost formation, the Witnet, is approximately 4000 feet thick and oonsists of coarse arkosic sandstones and conglomerates; the formation contains no fossils. The middle formation, the Kinnick, is 1900 feet thick and consists of massively bedded tuffs, agglomerates, and andesitio lavas; it is of lower Miocene age. The upper formation, the Bopesta, is more than 4000 feet thick and is made up of a fine grain sandstone; it was deposited in upper Miocene time. A Quaternary basalt is also present. Deformation first occurred in pre-Kinnick (lower Miocene) time as a major thrust fault placing crystalline rocks over Witnet. The motion was toward the north-northwest, or perpendicular to the Garlock Fault. In middle Miocene time, folding and minor thrusting parallel to the Garlock Fault occurred. In post Miocene time, broad folds parallel to the Garlock were formed and uplift on the north side of the fault took place. The writer has concluded that this indicates activity on the Garlock fault in pre-lower Miocene time with less intense but continued activity to the present