was it extended?
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.
Geology of the Grand Canyon area
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. T
what is the second layer of the grand canyon made of It is made up of nearly 40 major sedimentary rock layers how many layers are there? 40 layers how did this form? By deposition  in warm, shallow seas and near ancient, long-gone sea shores in western North America. do the layers have any names? One of them is the Vishnu Basement Rocks where is this canyon located? Arizona, United States. how big is it? thermochronometry showws that it  reached a depth near to the modern depth by 20 Ma
wiki:13001581
Geology of the Grand Canyon area [SEP] Uplift and nearby extension
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.