| Abstract: | The Keystone-Muddy Mountain thrust sheet was displaced for several tens of kilometres across the land's surface in Cretaceous times. Its movement is related to the emplacement of the Sierra Nevada batholith, which provided a source of compressive stress over a period of about 140 Ma.The mechanical analysis presented here examines the stresses operating throughout the whole thrust sheet (i.e. the “toe”, “ramp” and “main thrust block”) which extends for approximately 200 km from front to rear. Frictional sliding can explain only the motion of the toe, the ramp and perhaps part of the main thrust block. A composite model, involving elastic upper and viscous lower layers, is used to account for the movement of most of the main thrust block. |
