How Were The Rocky Mountains Formed?

Scenic winter views of the Rocky Mountains, Peter Lougheed Provincial Park, Alberta, Canada. Image credit: BGSmith/
  • Water from the Rockies supplies about a quarter of the United States.
  • Pikes Peak is the second most visited peak in the world.
  • The Rocky Mountain Range is a series of 100 separate mountain ranges, rather than one continuous mountain range.

The Rocky Mountains, or the Rockies, are famous across the globe for being one of the most picturesque mountain ranges on earth. The range spans a distance of around 3,000 miles and varies from 70 to 300 miles in width. Mount Elbert is the tallest mountain in the North American side of the Rockies, it stands at over 14,000 feet above sea level, and Mount Robson is the highest peak in the Canadian Rockies, reaching a height of 12,972 feet. But what are the Rocky Mountains? And how were they formed? Read on below to find out.

What Are The Rocky Mountains?

The surreal scenery of the Rocky Mountains in Banff National Park, Alberta, Canada. Image credit: Zhukova Valentyna/

The Rocky Mountains are a mountain range that stretches from New Mexico, through Colorado, Montana, Wyoming and Idaho before crossing the border into Canada, where they dominate British Colombia and Alberta. The Rocky Mountains forms the Continental Divide; they separate the watersheds of the Pacific Ocean from the Atlantic Ocean. The Rockies are a very popular tourist spot; they attract visitors from all over the world. Activities like hiking, camping and fishing are common here.

How Were The Rocky Mountains Formed?

A woman hiking on the Rockies in Colorado with her dog. Image credit: Larry Barrett/

The mountains began as a series of rocks, with the interior mountain range consisting of pieces of continental crust that are over one billion years old.

The Rocky Mountains formed during the Laramide orogeny period between 80 million to 55 million years ago. The Laramide orogeny period, also known as the mountain-building period, saw the Farallon ocean plate move underneath the North American tectonic plate at a low angle. This unusual subduction resulted in the forming of mountains, but further inland than what would be expected of this kind of tectonic activity. A series of pulses in conjunction with strong tectonic activity caused the earth’s crust to pile on top of each other; this began the formation of the Rocky Mountains along the west of North America. 

The mountains get their shape from the erosion that has taken place over the last 60 million years. The glaciers of the Pleistocene and Holocene Epochs had a particular impact in forming the Rockies. The rocks and sediment in the moving glaciers carved out the landscape and created the rugged mountains that still stand today. Remnants of the ice ages can still be found throughout the Rockies’ national parks in the form of much smaller glaciers, moraines and glacial lakes.

Impact Of Climate Change On The Rocky Mountains

Jasper National Park in the Rocky Mountains. Image credit: Kavram/

The Rocky Mountains National Park comprises three ecosystems: The Montane, the Subalpine and the Alpine. However, climate change is having a significant impact on the Rockies. As the earth’s temperature increases, the Rocky Mountains’ snowpack will melt earlier. This will result in less water available for plants, animals and farmlands in the summer months. Less water available in the summer makes soil drier, which may become inhospitable for many native plant species. In addition, warmer weather and drier soils increase the risk of wildfires, which will be hugely detrimental to the parks’ ecosystems and result in a change to the Rocky Mountains’ landscape.


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