Abstract: Plate Tectonic Constraints on the History of the Transverse Ranges

Tanya Atwater, Joann Stock

During the late Cenozoic, the Transverse Ranges formed a portion of the Pacific-North American plate boundary. Plate kinematic models for this plate boundary help constrain the tectonic history of the Transverse Ranges in two ways. (1) The reconstructed locations of the Transverse Ranges block from the mid-Cenozoic forward in time should lie within the Pacific-North American plate contact zones predicted using global plate circuit solutions. These locations and their uncertainties are still being revised. We report refinements resulting from new data sets in the South Pacific Ocean and from considerations concerning possible internal deformations of Antarctica. (2) The strain history recorded within the Transverse Ranges should reflect the configuration of the plate boundary to the no th and south of the region and changes within that configuration. Particularly important is the transfer of Baja California from the North American to the Pacific plate, since this shift profoundly reconfigures the plate boundary and the stress regime within southern California. The present configuration, with the southern plate boundary located within the Gulf of California and with the resulting transpressional regime in southern California, appears to have been applicable for about the last five million years. For the previous five to seven million years, evidence for partitioning of strain between Gulf and Pacific rim sites yields a more ambiguous strain prediction.

AAPG Search and Discovery Article #90981©1994 AAPG Pacific Section Meeting, Ventura, California, April 27-29, 1994