Strike-Slip Offset Along the McKittrick Fault, Western Kern County, California

J. R. Bowersox, Deborah M. Olson

Reconstructions of offset Miocene strata in McKittrick and northern Midway-Sunset fields, western Kern County, California, show about 7 mi (11 km) of post-Miocene right-lateral offset along the McKittrick fault. Detailed correlations of facies within the Potter sand, an informal member of the late Miocene Reef Ridge formation, in these fields show consistent stratigraphic character when the offset of the McKittrick fault is removed. Achieving this correlation allows the further correlation of Stevens sands, an informal member of the underlying Monterey Formation, between Midway-Sunset and McKittrick fields, including the feeder channels of these turbidite deposits. Facies are more continuous in a dip direction than they are along strike, facilitating their use as piercing points along the fault. The McKittrick fault parallels a feature long mapped as a right-lateral structure, the Bacon Hills fault, along the southwestern edge of the Cymric field. The McKittrick fault has always been considered to have vertical separation only. However, strike-slip motion as now proposed for it clarifies a structural problem that has been unexplained: the resemblance of the multiple thrust slices along the McKittrick fault in northern Midway-Sunset field and southeast McKittrick to the "palm structures" of Sylvester and Smith, but for which the requisite strike-slip displacement was not proved. Further evidence for this structural interpretation is provided by the presence of northeast-southwest-trending strike-slip faults in McKittrick Valley, which are explained by this model as differential slip taking up rotation between the McKittrick and Bacon Hills faults.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.