 The Laramide orogeny affected all of western North America by helping to build the American cordillera. The Kaibab Uplift, Monument Upwarp, the Uinta Mountains, San Rafael Swell, and the Rocky Mountains were uplifted, at least in part, by the Laramide orogeny. This major mountain-building event started near the end of the Mesozoic, around 75 million years ago, and continued into the Eocene period of the Cenozoic. It was caused by subduction off the western coast of North America. Major faults that trend north – south and cross the canyon area were reactivated by this uplift. Many of these faults are Precambrian in age and are still active today. Streams draining the Rocky Mountains in early Miocene time terminated in landlocked basins in Utah, Arizona and Nevada but there is no evidence for a major river.
