Fault chronology and uplift history of the southern Wind River Range, Wyoming: implications for Laramide and post-Laramide deformation in the Rocky Mountain foreland

The stratigraphy, provenance, and structural involvement of tectogenic sedimentary rocks along the southern and western margins of the Wind River Range in western Wyoming record a complex Laramide and later uplift history and identify the timing and position of individual faulting events. The chronology of these events is: 1) main uplift of the range of displacement on the Wind River fault between 90 and 49 to 50 Ma, 2) the formation of reverse faults in the hanging wall of the Wind River fault ca. 50 to 51 Ma, 3) sagging of the toe of the Wind River fault into sedimentary fill of the Green River basin between 46 and 23 Ma, 4) uplift of the core of the range along reactivated Precambrian shear zones between 30 and 23 Ma, and 5) collapse of the southern part of the range along normal faults beginning at 13 Ma. Initial uplift of the range as early as 110 Ma and prior to displacement on the Wind River fault suggests either a pre-Laramide event of unknown origin or that Laramide crustal shortening began nearly 35 m.y. earlier than commonly assumed. -from Authors