Rifting and Inversion Along the Palos Verdes Fault Zone San Pedro Shelf, Offshore Southern California

Abstract

This study examines the relationship of the Palos Verdes Fault Zone (PVFZ), an important fault zone in the Inner Borderland (IB), to the Palos Verdes Anticlinorium, Wilmington Graben, and other structures through detailed mapping of the fault zone constructed from high resolution 2D and 3D seismic reflection data and well logs. The data reveal a Mohnian-Delmontian trough, controlled by rifting and predating Palos Verdes Anticlinorium uplift, along the western PVFZ boundary. Sediment growth in the trough, the bulk of which occurred during the Mohnian, locally persisted into the Repettian. The western PVFZ boundary fault then transitioned to a transpressional regime beginning during the Repettian, inverting trough sediments. Typical of transpressional restraining bends along strike-slip faulting, varying degrees of inversion occur along the fault, with moderate inversion occurring on the central shelf with areas of little to no inversion to the north and south, all bounded by extreme inversion in the Palos Verdes Peninsula to the north and Lasuen Knoll to the south. The present location and geometry of the PVFZ with its various restraining and releasing bends, is potentially a product of the early rifting episode, which is related to other sub-parallel major IB rifts, such as San Pedro Basin, San Diego Trough, and Los Angeles Basin. At roughly 65 km long, 1-7 km wide, and 1-1.5 km deep, the PVFZ trough is much narrower than the other IB basins, except the San Diego Trough.

AAPG Datapages/Search and Discovery Article #90339 ©2019 AAPG Pacific Section Convention 2019, Long Beach, California, April 1-3, 2019