Tejon Formation
Tejon Formation
Eocene
Consists of a faulted and moderately folded sequence of marine shale, sandstone, conglomerate, and local breccia that crops out in the San Emigdio Mountains in southwestern map area.
Lower strata consist of coarser conglomerate and sandstone to pebbly sandstone, with a discontinuous coarse basal breccia, grading laterally to finer-grained sandstone and shale; upper strata consist of sandstone with interbedded conglomerate and shale (Nilsen, 1987).
Shale is typically thin bedded or platy and micaceous to argillaceous and locally silty to sandy; sandstone is arkosic, variably resistant and ledgy or friable, and fine to coarse grained and locally pebbly, and rarely flat stratified and well sorted (indicative of beach sand); conglomerate may include clasts of chert, quartz, porphyry, granite, and various other rock types sourced from the western San Emigdio mafic complex (Nilsen, 1987; Kellogg and others, 2008; Chapman and Saleeby, 2012).
Inferred depositional environments are near shore, shallow marine, brackish water to lagoon or (locally) beach, grading laterally to deeper marine (Nilsen, 1987).
Attains a maximum thickness of 1,200 to 1,300 m in the central part of the range, but thins laterally to 300 m (Be, 1983; Nilsen, 1987; Kellogg and others, 2008).
Locally fossiliferous, containing foraminifera and invertebrate megafossils, including numerous species of gastropods, pelecypods, and lesser other types, all diagnostic of Eocene age (Nilsen, 1987).
Coarser shallow marine facies hosts substantial oil (Nilsen, 1987). Separated from time-equivalent Domengine Formation by the Bakersfield arch depositional barrier present in the subsurface (Be, 1983).