The late Jurassic to early Cretaceous history of the Peninsular Ranges, California is thought to involve collision of an oceanic arc with cratonic North America, collapsing a sedimentary basin between. However, a prominent shear zone thought to record this collision has been shown to involve rocks of too young an age and has extensional, not contractional kinematics. This project will involve detailed mapping of the Cuyamaca- Laguna Mountains shear zone, study of oriented samples and radiometric age dating. Results should provide a test of the collisional model for the late Jurassic to early Cretaceous of the Peninsular Ranges.
