EVOLUTION OF THE SAN-ANDREAS FAULT

Existing transform fault models for the evolution of the San Andreas system are inconsistent with many findings on displacement, timing of movement, and slip rate for the faults of the San Andreas system. Palin-spastic reconstruction of paleogeologic features that evolved during and prior to the evolution of the fault system shows that throughgoing intra-continental faults of the San Andreas sytem emerged at 20-17 Ma and evolved in at least three distinct phases. Although it provides an appealingly simple plate tectonic framework for the existence of the San Andreas fault system, assigning a transform role to the San Andreas system raises questions about why the San Andreas fault system developed intracontinentally rather than along the boundary between oceanic and continental crust. -from Authors