9628540 Wells Theoretical and analog models of contractional mountain belts have shown that extensions can occur within mountain belt interiors both synchronously with and immediately following contraction. The major implication for understanding the dynamics of mountain building have been outlined, but many important aspects remain unclear. This project will utilize an area where the effects of magmatism on the kinematic sequence within a contractional mountain belt can be studied. The eastern Mojave Desert is a setting where a backarc fold and thrust belt intersects and is coincident with a coeval magmatic arc. This geometry, with differing extension directions should allow a test of whether a discontinuous belt of Cretaceous extension exists across the eastern Mojave, and illuminate the potential regional controls that have tipped the scale in favor of gravitational forces leading to extension. Successful outcome of this work will be applicable to other orogens.
