Sandbox Thrust Faults

This movie shows a model of folding and thrust faulting that when plates collide along a convergent plate boundary. During the Late Jurassic and through the Cretaceous Period, Utah and Nevada were undergoing the same compressional folding and thrusting like what you see in this sandbox demonstration. Watch carefully as folds form then are cut by low angle thrust faults that begin stacking the detached blocks upon one another. Then as the pressure is relaxed the mountain front collapses into the valley, just as the front of the Wasatch Mountains has done as the Sevier compressional event relaxed and the region begin to extend.

(Demonstration produced by Ron Harris)