Geologic map of a portion of the Tejon Quadrangle, Los Angeles County, California: Supplement 1 from "The Geology of the Southeastern Portion of the Tejon Quadrangle, California" (Thesis)

Description

Rocks in the southeasterly portion of the Tejon Quadrangle include pre-Cambrian (?), Paleozoic (?), Jurassic granitic rocks, and a thick series of Cenozoic sediments. All epochs of the two periods of the Cenozoic are represented. Lower Eocene (Martinez) marine beds are overlain unconformably by middle Eocene (Domengine) rocks, also marine. Oligocene land-laid beds occur in three isolated patches. A full series of Miocene rocks is present, from Vaqueros through Temblor to Modelo. These are all marine and in addition there is the Mint Canyon formation as the landward equivalent of a portion of the Modelo. An unconformity occurs at the base of the Temblor. Pliocene is represented in the southerly part of the area by marine Pico beds and in the north by the Ridge Route formation, largely lacustrine. These are both unconformable with the underlying Miocene rocks and the former are overlain, also unconformably, by land-laid Pleistocene (Saugus). Upper Pleistocene terraces border some of the streams, while Recent alluvium extends well up the larger stream channels. Deformation has been brought about by static load, intrusion and dynamic compressive forces. The last named have broken the area into three blocks separated by major faults and faulted within themselves. A large syncline has developed in the central block and an upward occurs athwart the trend of other structures. The westerly block is complicated by a large overturn.

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