LOW-ANGLE NORMAL FAULTING ALONG SOUTHERN COASTAL CALIFORNIA AS DISPLAYED BY THE HANGING-WALL ROLLOVER GEOMETRY OF THE SAN ONOFRE BRECCIA
M. Fattahipour, E.G. Frost, 1996. "LOW-ANGLE NORMAL FAULTING ALONG SOUTHERN COASTAL CALIFORNIA AS DISPLAYED BY THE HANGING-WALL ROLLOVER GEOMETRY OF THE SAN ONOFRE BRECCIA", Field Conference Guide, AAPG National Convention, San Diego, California, Patrick L Abbott, John D Cooper
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In coastal southern California, west of the principal strand of the San Andreas fault system, structural features formed since the Cretaceous have primarily been attributed to transform motion along the San Andreas fault system (Fig. 1). Where extensional deformation is clearly present in coastal southern California, it has generally been attributed to wrench faulting associated with strike-slip motion of the San Andreas fault system (e.g., Wilcox and others, 1973; Crowell, 1974). Strike-slip versus extensional models for the evolution of coastal southern California had previously been discussed but widely dismissed in favor of transform tectonics by most workers. The continued refinement of the plate configurations for the Cenozoic and the re-evaluation of some of the structural features in coastal southern California suggest that there was indeed a distinct Miocene extensional event. This deformation occurred contemporaneously with the extensional events of the Colorado River region and other portions of the Basin-and-Range province of the western United States and Mexico. Recently, however, the presence of regional detachment fault systems have been verified by regional seismic reflection profiles processed by the U.S.G.S.