9317044 Hoisch Theoretical and physical models as well as field studies suggest that complex structural histories involving alternating contraction and extension can develop within the interior of contractional orogenic belts, essentially moderating crustal thickness during the growth of the orogenic belt. This project will attempt to test these models by use of mid-crustal exposure of the hinterland of Sevier Orogen in the Raft River and Grouse Creek Mountains of northwestern Utah. The work will involve structural mapping, Metamorphic thermobarometry, P-T-t path modeling, and several geochronologic techniques. This study will address several components of the deformation history of the area and test several existing models for middle crustal evolution during Mesozoic regional contraction and post-orogenic extension. It will also help link the possible coeval deformations between the hinterland and the foreland thrust belt. ***
