Post-Laramide (Oligocene) uplift in the Wind River Range, Wyoming

In late Oligocene time, the crest of the Wind River Range was uplifted from an erosion surface that formed during Laramide (Late Cretaceous-early Eocene) deformation. This uplift created the highest peaks in the Wyoming foreland and is indicated by rejuvenation of the range as a sediment source and by the physiography of the peaks. Differential movement of basement blocks in the core of the range is identified by apatite fission-track data. We distinguish this deformation from earlier Laramide compression and Neogene normal faulting and speculate that it occurred when Precambrian shear zones were reactivated in response to local flexural stress in the Laramide subsidence-uplift couple. -Authors