Series of mountain-building events that affected much of western North America in Late Cretaceous and Early Tertiary time (с 65 million years ago).
The Laramide orogeny originally was believed to mark the Cretaceous-Tertiary boundary. It is now considered to have consisted of many separate pulses of deformation that varied in intensity and age from place to place. Laramide rocks, however, were generally created around the Cretaceous-Tertiary time boundary.