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AN ABSTRACT OF THE THESIS OF

LEONARD TIMOTHY STITT for the degree of MASTER OF SCIENCE

GEOLOGY presented on June 5, 1980

Title: GEOLOGY OF THE VENTURA AND SOLEDAD BASINS

IN THE VICINITY OF CASTAI LOS ANGELES

COUNTY, CALIFORNIA -

Abstract approved: Signature redacted for privacy.
' Dr. RoberIV. Yeats

Surface and subsurface mapping are combined to determine the

geologic history along the San Gabriel fault near the town of Castaic.

Palomas Gneiss, Whitaker Granodiorite, and Pelona Schist are base-

ment terranes encountered in the subsurface. West of the San

Gabriel fault, basement is unconlormably overlain by marine middle

to late Miocene Modelo Formation. The late Miocene to early Plio-

cene Towsley Formation overlies the Modelo and was deposited in a

submarine fan environment. East of the San Gabriel fault, marine

Paleocene San Francisquito Formation accumulated while Pelona

Schist was undergoing regional metamorphism at depths of 20 to 27

kilometers. Nonmarine Oligocene (?) Vasquez Formation is faulted

against both the Pelona Schist and San Francisquito Formation.

Charlie Canyon Megabreccia accumulated in late Oligocene (?) time

as a large landslide deposit. The source is controversial, but may