Provenance of tertiary conglomerates, eastern San Francisco Bay Area, California

This thesis presents the results of 16 point counts of conglomerates in the Tertiary Kirker Formation and the Miocene San Pablo Group (the Cierbo, Briones and Neroly sandstones). The Kirker Formation contains andesitic clasts, pointing to a Miocene age of less than 20 Ma. The Kirker and Cierbo have a metamorphic-dominated provenance, whereas the Neroly is dominated by Sierran volcanic clasts. Basalt clasts, derived from the northern Sierra, are absent from the Neroly south of Mount Diablo. This absence, debris-flow deposits in the Neroly, and angular unconformities between the units north of Mount Diablo suggest that a paleohigh occupied the present position of Mount Diablo. To the west at Happy Valley, the Neroly contains no volcanic clasts, suggesting a previously greater separation between it and the Berkeley Hills Volcanics due to later dextral slip.