Provenance and Detrital-Zircon Analyses of the Cajon Valley, Punchbowl and Mint Canyon Formations and Their Correlated Lithofacies in Central and Southern California
Stang, Dallon M.; Ingersol, Raymond V.; Hoyt, Johanna F.; Coffey, Kevin T.; Jacobsen, Carl E.; and Grove, Marty
Re-evaluation of formations in southern California using detailed petrographic and detrital-zircon analyses to determine comparable lithofacies has played a critical role in determining the paleotectonic and geographic evolution of the western United States. Arkosic sandstone of the lower Miocene Cajon Valley formation is exposed on the SW edge of the Mojave block. The formation is juxtaposed against Mesozoic granitoid and Paleozoic metamorphic rocks by the San Andreas fault. Early work in Cajon Valley referred to the formation as Punchbowl, due to its similar appearance to the Punchbowl Formation at Devil’s Punchbowl. However, subsequent paleontological work placed Hemingfordian-Barstovian ages on the Cajon Valley strata, as opposed to the Clarendonian-Hemphillian Punchbowl Formation. New paleocurrent data and field mapping suggest that the Cajon Valley strata are likely to have been part of a through-going drainage system. Potential offset equivalents of the Cajon Valley, Mint Canyon and Punchbowl formations are found by restoring 310 km of right slip on the San Andreas fault system (San Gabriel and southern San Andreas faults), which postdates deposition of these formations. Detrital-zircon and petrographic analyses of sandstone samples from these offset equivalents are compared to constrain timing and magnitude of movement on the San Andreas fault system.
AAPG Search and Discovery Article #90162©2013 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Monterey, California, April 19-25, 2013