Abstract

The Bakersfield Arch is a major westward plunging structural bowing on the east side of the soutern San Joaquin Valley extending from Porterville, on the north, approximately 55 miles SSE to the vicinity of Bear Mountain. It plunges SSW into the San Joaquin Basin for approximately 20 miles. The Arch is the site of several major oil fields which produced approximately 66 MMBO during 1984. Oil production is from sandstone and siltstone of Tertiary age and younger, and from fractured basement rocks.

Structural evolution of the Bakersfield Arch began with the southwestward movement of the Western U.S. in response to plate tectonic forces. This movement resulted in westerly (clockwise) rotation of the southern part of the Sierra Nevada Batholith and the southwesterly projection of the Tehachapi Mountains granitic salient. The Tehachapi Mountains granitic is bounded on the south by the left-lateral Garlock fault and on the northwest by the right-lateral White Wolf and Kern Canyon faults. It is proposed that southwesterly pressure on the White Wolf-Kern Canyon fault has caused the Greenhorn Mountains block of the Sierra Nevada Batholith to be pushed (wedged) westward into the San Joaquin Basin. The Greenhorn Mountains are the core of the Bakersfield Arch. Movement on the Garlock fault to initiate the Bakersfield Arch growth probably began in the Middle Miocene.