The Rocky Mountain

The Rocky Mountain Range was formed 47-70 million years ago in a time period know as the Laramide Orogeny period. Mountain ranges tend to form 200 miles of their subduction zone. As we can see the Sierra Nevada Mountian range was formed 200 miles of its subduction zone. As we can see the Rocky Mountains are a special case. When the Rockies were being formed, the Farallon plate slid under the North American Plate. This resulted with a low angle of subduction and causing the Rockies to form several hundred mile off the subductoin zone. It is also believed that as a result of this low subduction angle, there was a larger amount of friction and interactoin with the continental mass. Because of this the Rocky Mountain range is so broad and high.