Stratigraphy of the Joaquin Ridge Sandstone: a Sand-rich Deep-water System

Christopher Mitchell
Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305

The Cretaceous Panoche Group of central California consists of over 7000 meters of deep-water mudstone, sandstone, and conglomerate. These deposits range in age from Albian to Maastrichtian and are part of the Great Valley Group. This succession was deposited in a rapidly subsiding forearc basin and is now exposed on the west flank of California’s Central Valley. Along the Joaquin Ridge twenty miles northwest of Coalinga, the Panoche Group has received little attention from either a detailed sedimentological or stratigraphic perspective.

Joaquin Ridge consists of thickly bedded sandstone cliffs several hundred meters high. These units can be followed along structural strike for tens of kilometers, potentially providing an excellent view of submarine fan architecture at a seismic scale. In light of advances in understanding deep-water deposits over the last several decades, these rocks deserve study in order to better constrain the evolution of basin filling, as well as to add to the inventory of deep-water reservoir analogs.

AAPG Search and Discovery Article #90076©2008 AAPG Pacific Section, Bakersfield, California