Wind River Mountains

The Wind River Mountains form a prominent range in NW Wyoming that trends NW-SE. The range constitutes a basement-cored uplift, with a NE-dipping thrust along its western flank, that formed during the Cretaceous-Tertiary Laramide orogeny. Precambrian crystalline basement and Paleozoic-Mesozoic cover rocks were thrust westward along the Wind River thrust and carried over Cretaceous-Tertiary sedimentary rocks of the Green River basin. The cover rocks show prominent folding that is well exposed at the northern end of the range, near Green River Lakes. The underlying basement rocks are strongly deformed along networks of deformation zones.

The Precambrian rocks show evidence for at least two generations of Precambrian deformation at high metamorphic grades that gave rise to prominent sets of shear zones. These structures are overprinted by networks of Laramide deformation zones that formed dominantly in the elastico-frictional regime and developed cataclasites. This prominent Laramide basement deformation by cataclastic flow is transferred upward into the cover rocks in the form of folds, with approximately equal amounts of shortening in the basement and cover rocks.

Geology