Recent advancements in geochronology, geologic mapping, and landslide characterization in basement rocks of the San Gabriel Mountains block

This field trip examines Paleoproterozoic basement, Neoproterozoic metasedimentary strata, and crosscutting Mesozoic intrusive rocks at Frazier Mountain, Placerita Canyon, and Limerock Canyon in the western San Gabriel Mountains block, California. We present new U-Pb zircon geochronology results that constrain the Proterozoic through Cretaceous tectonic and magmatic history. The excursion ends in San Antonio Canyon in the eastern San Gabriel Mountains where several large rock avalanche deposits are sourced from distinct basement rocks. 10Be surface exposure ages and post-infrared infrared stimulated luminescence burial ages demonstrate late Pleistocene to Holocene movements for these landslides.