Date of Award
Master of Science (MS)
The depositional history of the southernmost region of the trough-shaped San Joaquin Basin spans from Upper Eocene to Recent time. The stratigraphy reveals both a predominantly marine environment which persisted until the Upper Pliocene, as well as nonmarine environments along the basin's margins. Folds and faults within the basin have resulted directly from movements along the San Andreas fault. Although the exact time of origin of the Big Bend is unclear, this major feature in the San Andreas fault's geometry has played an important role in recent crustal tectonics of southern California. Significantly, the southern San Joaquin's depocenter has undergone an acceleration in its rate of subsidence since late Pliocene time. Data on partial loss of radiogenic argon obtained from detrital microclines analyzed by 40Ar/ 39Ar stepwise heating technique provides information on temperatures experienced at various stratigraphic levels in the basin. The results agree with a thermal history predicted for the basin's recent and present rapid rate of subsidence.
Bé, Kenneth, "Geological and thermal aspects of the southern San Joaquin Basin, California: application of the 40Ar/39Ar stepwise heating technique to detrital microclines" (1983). Geology Theses and Dissertations. 10.