Date and Time
Bath Royal Literary and Scientific Institution, 16-18 Queen Square, Bath BA1 2HN
The North American Cordilleran mountain chain runs N-S along western North America, and reaches up to ~ 500 km in width. The chain consists of a number of Mt ranges such as the Rocky Mountains and Coast Ranges, along with a variety of geological entities including the Basin and Range Province, Colorado plateau, Cascade volcanic arc, Columbia flood basalts and the Yellowstone plateau. These different regions record a remarkable geological evolution over a period greater than the entire Phanerozoic. This evolution records the change of the western coast from a passive margin, marking the breakup of the Rodinia supercontinent in the late Precambrian, to a active subducting margin culminating in the Larimide orogeny and the formation of the Cordilleran mountain belts. The Tertiary evolution marks the orogenic collapse phase, with the plate boundary between the Pacific and North American plates changing from a destructive margin to one involving the two transcurrent faults of the San Andreas and Queen Charlotte zones, separated by the remnant of the destructive margin that has given rise to the Cascades volcanic chain.
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