Detailed analysis of the geology of western North America in relation to the motion of plates in the eastern Pacific Ocean show four iterations of a basic subduction cycle:
1. Rapid subduction (>10 cm/year) and arc compression for approximately 30 m.y. best exposed today by porphyry copper deposits.
2. Formation of granitic batholiths over a few million years in a trans-tensional regime topped by major silicic volcanic provinces.
3. Pulling apart of the subducted plate, relieving trench normal compression, opening of the Basin and Range.
4. Onset of major strike-slip motion. © 2008 - Teton Tectonics - All rights reserved. Plate Tectonics |