I would try to describe but I may go ahead a little bit
Explanation:
TheRockyMountainsare often defined as stretching from the LiardRiverin BritishColumbiasouth to the headwaters of theRiograndein New Mexico.The Rockies vary in width from 110 to 480 Km, the Rocky Mountains contain the highest peaks in central north America.
The Rocky Mountains formed 80 million to 55 million years ago, during the Larami de orogeny ,in which a number of plates began sliding underneath the north American plate.the angle of subduction was shallow resulting in a broad belt if mountain running down western north America
