Collaborative Research: Timing and Mechanism of Collapse of the Late Cretaceous-Early Tertiary California Margin Based on Detrital Zircon Geochronology

Iowa State University, Ames IA

Investigators

Abstract

0106123 Jacobson 0106881 Barth The late Mesozoic to early Tertiary geology of California is characterized by an arc-forearc-accretionary wedge sequence produced during convergence with the Farallon plate. These elements have been severely disrupted in southern California, resulting in eastern facies being emplaced over western and underthrusting of the enigmatic Pelona-Orocopia-Rand Schists. This project will follow up on prior results of work on this system that indicate eastward younging in the schists, and that provenance of the schists matches the provenance in the overlying basement rocks. The results of this extensive detrital zircon dating effort is expected to discriminate between several possible tectonic scenarios for the development of this complex geology. Results are key to understanding the late Mesozoic to early tertiary tectonic environment of the California sector of the western cordillera.