A summary of the Cenozoic stratigraphy and geologic history of the Coalinga region, central California

Cenozoic strata along the southwest side of the San Joaquin Valley provide a nearly complete record of the depositional history and structural evolution of this large sedimentary basin. The diverse sedimentary facies represented are evidence of repeated cycles of transgression and regression that are due to relative changes in sea level. These changes, in turn, can be interpreted in terms of either tectonic activity - that is, uplift or subsidence - or eustatic sea-level change. This chapter briefly describes the stratigraphy and outlines the geologic history of the region surrounding Coalinga and the epicenter of the May 2, 1983, earthquake, concentrating on Cenozoic time, during which tectonic relations most relevant to the existing stress field were established. This paper describes the geologic setting; Paleogene history; and Neogene and Quaternary history.