To see the world in a grain of sand: Sedimentary signals of young faulting along an old strand of the San Andreas Fault
Active continental-scale transform faults create mountainous geography, microclimates, and biodiversity along tectonic plate boundaries. In the Transverse Ranges of southern California, the San Andreas Fault (SAF) accommodates motion between the Pacific and North American plates and is responsible for >100s km of horizontal displacement during faulting in the past 20 million years. The Mission Creek strand of the San Andreas Fault is a major geologic structure with ~90 km of strike-slip displacement but is currently mapped as inactive. Fault reconstructions are based on the restored positions of similar basement rocks and sedimentary deposits, now disconnected from their original upland sources. While these correlations are nominally accepted, evidence for some fault reconstructions is inconclusive and debate persists regarding the chronology, provenance, and pre-faulting paleogeography. This presentation summarizes our current and ongoing work on fault slip reconstructions and paleogeography of the Mission Creek strand both on 105 and 106 year timescales.