Sevier orogeny region which caused folding and thrusting. The mountains that were formed as a result were located in western Utah and eastern Nevada. The size, shape, and depth of the thrust faults created in the Sevier event are determined by seismic studies and deep well data because they are mostly still buried by overlying rock and sediment. The Sevier and Laramide orogenies ended when subduction along the western edge of North America was overcome by western extension of the North American Plate to start the Basin and Range Orogeny. The well known and familiar Basin and Range faults cut the older
Andean orogeny and then to the opening of the Drake Passage 45 million years ago. The separation from Antarctica changed the tectonics of the Fuegian Andes into a transpressive regime with transform faults. About 15 million years ago in the Miocene the Chile Ridge begun to subduct beneath the southern tip of Patagonia (55° S). The point of subduction, the triple junction has gradually moved to the north and lies at present at 47° S. The subduction of the ridge has created a northward moving "window" or gap in the asthenosphere beneath South America. Andean orogeny The Andean orogeny () is an