Timing and extent of Neogene tectonic rotation in the western Transverse Ranges, California

Strike-slip motion of a mega-splay fault system in the Nankai oblique subduction zone

“…The en echelon shallow branched thrusts extracted from seismic data (Figure 4c) can be interpreted as part of this positive flower structure (Figure 8). Because positive flower structures typically include thrusts with minor displacement surrounding a main strike-slip fault (e.g., Hornafius et al 1986;Murphy and Fuis 2010) and because the shallow splay fault was much more active in the past (approximately 2 Ma), only dip-slip features are observed in core samples of the shallow branched megasplay fault (Ashi et al 2008).…”

Upper Crustal Structure from the Santa Monica Mountains to the Sierra Nevada, Southern California: Tomographic Results from the Los Angeles Regional Seismic Experiment, Phase II (LARSE II)

“…1) crosses the complex geology of the western and central Transverse Ranges, Mojave Desert, Tehachapi Mountains, and Sierra Nevada. The western Transverse Ranges, including the Santa Monica Mountains, San Fernando Valley, and Santa Susana Mountains, are believed to have rotated more than 90Њ clockwise since the early Miocene from a position offshore of the Peninsular Ranges (Hornafius et al, 1986;Crouch and Suppe, 1993). The southernmost range in this province, the Santa Monica Mountains, is an anticlinorium containing in its core Mesozoic igneous and metamorphic rocks (Dibblee, 1992).…”

Paleomagnetic evidence of localized vertical axis rotation during Neogene extension, Sierra San Fermín, northeastern Baja California, Mexico

“…Our paleomagnetic data demonstrate that clockwise rotation of structural blocks, in addition to extensional and strike-slip faulting, accounts for significant late Miocene to Recent deformation in this area. Rigid body rotation can contribute an important component of relative plate displacement through time [e.g., Hornafius et al, 1986;Luyendyk, 1990;Dickinson, 1996] and may allow extension independent of that produced by pure dip-slip motion. Our data suggest that this is the case for northeastern Baja California.…”