The Transverse Ranges of southern California trend anomalously east-west in a tectonic regime otherwise dominated by the northwest-southeast trending San Andreas fault system. Plate tectonics theory offers an explanation for the origin of the Transverse Ranges. Convergence of the North American Plate (NAP) with the East Pacific Rise (EPR) and the overriding of the EPR by the NAP south of the Mendocino Fracture Zone led to development of northwest-trending, right-lateral faults on the leading edge of the NAP in southern California. Subsequent deflection of the NAP to the southwest by the still active Gorda-Juan de Fuca Ridge segment of the EPR resulted in southwesterly deflection of the San Andreas fault (SAF) forming the big bend in that fault.

These plate movements are responsible for the east-west trend and juxtaposition of major components of the Transverse Ranges. The east-west-trending Santa Ynez Range represents northward-moving rocks on the south side of the SAF, which were deflected westerly and did not negotiate the big bend in that fault. The elevated central part of the Transverse Ranges from the big bend southeasterly to Cajon Pass is under compression as northwesterly moving blocks on the south side of the SAF converge on southwesterly moving blocks on the north side of that fault. The easternmost range in the Transverse Ranges, the San Bernardino Mountains, is under similar compression on the north side of the bent portion of the SAF.

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