Abstract: Neogene Evolution and Stratigraphy of the Santa Maria Basin, California: Pacific Section SEPM Fall 2000 Field Trip

BEHL, RICHARD, California State U Long Beach, Long Beach, CA 

The Neogene Santa Maria basin holds a unique stratigraphic record of the complex tectonic, paleoceanographic, and continental evolution of the central California margin. The Neogene history of the basin began at ~18 Ma with deposition of the nonmarine-shallow marine Lospe Formation on the eroded skeleton of the Franciscan Assemblage, Great Valley Sequence, and the Point Sal ophiolite, in conjunction with extrusive igneous rocks associated with the Obispo Formation and Tranquillon Volcanics. Abrupt deepening from neritic to bathyal depths is recorded by the Point Sal Formation and the petroliferous Monterey Formation. Late Miocene through Pliocene shortening and deformation associated with rearrangement of the transform plate boundary created strong lateral facies variations and the uneven distribution of the overlying Sisquoc and Foxen Mudstone Formations as some areas within the basin rapidly shoaled while others remained under deep water. Continued Plio-Pleistocene shortening of the Santa Maria basin between the rotating Western Transverse Ranges and the southern Coast Ranges resulted in overall uplift and regression recorded by deposition of the neritic Careaga Sandstone, and the nonmarine Paso Robles Formation and Orcutt Sand. We will examine this beautiful and fascinating sequence on the Pacific Section SEPM's Fall 2000 Field Trip - join us!

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California