Final answer:
The Rocky Mountains started to be uplifted 65 million years ago during the Late Paleozoic and main growth occurred during the Laramide Orogeny in the Late Mesozoic and Early Cenozoic.
Step-by-step explanation:
The Rocky Mountains started to be uplifted 65 million years ago during the Late Paleozoic and the main growth occurred during the Laramide Orogeny in the Late Mesozoic and Early Cenozoic. The Rocky Mountains are an immense mountain range that stretches from New Mexico to Northern Canada. They were formed through low-angle subduction, which caused deformation in the overlying plate. The mountains have since been glaciated and eroded, resulting in rounded peaks.