The Cheyenne belt of southeastern Wyoming separates the Archean Wyoming Province from accreted island-arc rocks of the Proterozoic Colorado Province. Along the suture, several parallel mylonite zones separate high grade, reactivated Archean crust north of the main fault zone. This project will focus on the development of this reactivated crust and will involve mapping, age dating and geochemical analysis. Results will help understand the details of the collision zone between the Archean Wyoming Province and the Proterozoic Colorado Province and may also provide insight into the deep-seated structural character of the root zone of a basement uplift in the external zone of a major collisional belt.