In the Sierra La Vibora near Caborca, Mexico, three structures occur: a thrust sheet of crystalline basement overlain by Proterozoic and Cambrian sedimentary formations thrust eastward upon Mesozoic clastics; asymmetric and overturned folds, northwest-southeast oriented, with southwest vergence; and low-angle extensional faults with top-to-the-west transport. The Pitiquito granodiorite, dated at 80 Ma by K-Ar techniques, was intruded after the thrusting, and the youngest rocks affected by thrusting are Albian to Cenomanian(?), indicating that thrusting occurred between about 95 and 80 Ma.

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