Rocky Mountains
The Rocky Mountains rose from the earth between 80 million and 55 million years ago during a period known as the Laramide orogeny. This massive geological event occurred when tectonic plates began sliding underneath the North American plate at an unusually shallow angle. The Farallon Plate dove beneath the continent, moving the focus of mountain building far inland compared to typical subduction zones. Scientists describe this process like pushing a rug across a hardwood floor, causing it to bunch up into wrinkles that became mountains. In Canada, the terranes and subduction act as the foot pushing the rug while the Canadian Shield serves as the solid floor. Some researchers propose a hit-and-run model where transient plate interactions distributed deformation far inland rather than relying solely on long-lived shallow-angle subduction. Just after the Laramide orogeny, the range stood as a high plateau likely exceeding three miles above sea level. Over the last 60 million years, erosion stripped away these high rocks to reveal the ancestral formations beneath. Periods of glaciation from the Pleistocene Epoch through the Holocene Epoch left their mark by forming U-shaped valleys and cirques. Recent glacial episodes included the Bull Lake Glaciation which began about 150,000 years ago and the Pinedale Glaciation which may have lasted until 15,000 to 20,000 years ago.
The Rocky Mountains span a latitude between the Liard River in British Columbia at 59 degrees North and the Rio Grande in New Mexico at 35 degrees North. This vast distance creates diverse environmental factors ranging from precipitation levels of 10 inches per year in southern valleys to over 40 inches locally in northern peaks. Ecologists divide the range into multiple biotic zones defined by tree support and indicator species presence. Two zones that do not support trees are the Plains and the Alpine tundra which varies from 8,000 feet in New Mexico to 11,000 feet near the Yukon. The U.S. Geological Survey defines ten forested zones including areas with pinyon pines, ponderosa pines, Douglas firs, and lodgepole pines. North America's largest herds of elk inhabit the Alberta, British Columbia foothills forests. European-American settlement has adversely impacted native species such as western toads, greenback cutthroat trout, and bighorn sheep. Apex predators like grizzly bears and wolf packs were extirpated from their original ranges but have partially recovered due to conservation measures. Other recovering species include the bald eagle and the peregrine falcon. The status of most species remains unknown due to incomplete information regarding population trends.
Since the last great ice age, indigenous peoples including the Apache, Arapaho, Blackfoot, Cheyenne, Shoshone, and Ute inhabited the Rocky Mountains. Paleo-Indians hunted now-extinct mammoth and ancient bison which was an animal 20% larger than modern bison in the foothills and valleys. Like modern tribes that followed them, these groups migrated to plains for bison in fall and winter while moving to mountains for fish and berries in spring and summer. In Colorado, rock walls built by Native Americans for driving game date back 5,400 to 5,800 years along with the crest of the Continental Divide. A growing body of scientific evidence indicates indigenous people had significant effects on mammal populations through hunting and vegetation patterns via deliberate burning. Recent human history shows rapid change following European contact starting with Francisco Vázquez de Coronado marching into the region in 1540. The Spanish founded Santa Fe in 1610 as the oldest continuous seat of government in the United States at the foot of the Rockies. The introduction of horses, metal tools, rifles, new diseases, and different cultures profoundly changed Native American cultures. Native American populations were extirpated from most historical ranges by disease, warfare, habitat loss, and continued assaults on their culture.
Sir Alexander Mackenzie became the first European to cross the Rocky Mountains in 1793 finding the upper reaches of the Fraser River. He reached the Pacific coast of what is now Canada on July 20 of that year completing the first recorded transcontinental crossing north of Mexico. The Lewis and Clark Expedition ran from 1804 to 1806 serving as the first scientific reconnaissance collecting specimens for botanists and zoologists. Mountain men primarily French, Spanish, and British roamed the mountains from 1720 to 1800 seeking mineral deposits and furs. The fur-trading North West Company established Rocky Mountain House as a trading post in present-day Alberta in 1799 while rivals Hudson's Bay Company established Acton House nearby. David Thompson followed the Columbia River to the Pacific Ocean on his 1811 expedition camping at the junction with the Snake River. By the Anglo-American Convention of 1818 the UK and US agreed to joint occupancy of lands further west to the Pacific Ocean along the 49th parallel. In 1846 Britain ceded all claim to Columbia District lands south of the 49th parallel to the United States resolving the Oregon boundary dispute. Thousands passed through the Rockies on the Oregon Trail beginning in the 1840s while Mormons began settling near the Great Salt Lake in 1847.
Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum, silver, tungsten, and zinc. The Climax mine near Leadville, Colorado was the largest producer of molybdenum in the world employing over 3,000 workers. Canada's largest coal mines are located near Fernie and Sparwood in British Columbia with additional sites near Hinton and Tumbler Ridge. Abandoned mines with their wakes of tailings and toxic wastes dot the landscape including eighty years of zinc mining that polluted the river near Eagle River in north-central Colorado. An economic analysis revealed cleanup could yield $2.3 million in additional revenue from recreation while the former owner faced a lawsuit for $4.8 million in cleanup costs in 1983. Coalbed methane supplies 7 percent of natural gas used in the U.S. with major sources in the San Juan Basin and Powder River Basin containing an estimated 38 trillion cubic feet of gas. Agriculture includes dryland and irrigated farming plus livestock grazing known as transhumance where herds move between high-elevation summer pastures and low-elevation winter pastures. Economic development has centered on mining, forestry, agriculture, and recreation alongside service industries supporting these sectors.
Every year scenic areas of the Rocky Mountains draw millions of tourists seeking to hike, camp, or engage in mountain sports. In the United States visitors flock to Yellowstone National Park established in 1872 as the world's first national park and Glacier National Park. Canada contains Banff National Park, Jasper National Park, Kootenay National Park, Waterton Lakes National Park, and Yoho National Park. Glacier National Park in Montana and Waterton Lakes National Park in Alberta border each other collectively known as Waterton-Glacier International Peace Park. In the winter skiing and snowboarding are main attractions with dozens of Rocky Mountain ski areas and resorts including Panorama and Kicking Horse in British Columbia. John Denver wrote the song Rocky Mountain High in 1972 which became one of two official state songs of Colorado. U.S. President Benjamin Harrison established several forest reserves in 1891, 1892 while Theodore Roosevelt extended the Medicine Bow Forest Reserve in 1905. Tents and camps evolved into ranches and farms while forts and train stations became towns and some towns grew into cities. Conservation and preservation ethics began taking hold even as settlers filled valleys and mining towns.
Common questions
When did the Rocky Mountains rise from the earth?
The Rocky Mountains rose from the earth between 80 million and 55 million years ago during a period known as the Laramide orogeny. This geological event occurred when tectonic plates began sliding underneath the North American plate at an unusually shallow angle.
Where do the Rocky Mountains span geographically in North America?
The Rocky Mountains span a latitude between the Liard River in British Columbia at 59 degrees North and the Rio Grande in New Mexico at 35 degrees North. This vast distance creates diverse environmental factors ranging from precipitation levels of 10 inches per year in southern valleys to over 40 inches locally in northern peaks.
Who were the first indigenous peoples to inhabit the Rocky Mountains after the last great ice age?
Indigenous peoples including the Apache, Arapaho, Blackfoot, Cheyenne, Shoshone, and Ute inhabited the Rocky Mountains since the last great ice age. Paleo-Indians hunted now-extinct mammoth and ancient bison which was an animal 20% larger than modern bison in the foothills and valleys.
When did Sir Alexander Mackenzie become the first European to cross the Rocky Mountains?
Sir Alexander Mackenzie became the first European to cross the Rocky Mountains in 1793 finding the upper reaches of the Fraser River. He reached the Pacific coast of what is now Canada on July 20 of that year completing the first recorded transcontinental crossing north of Mexico.
What minerals are found in significant deposits within the Rocky Mountains?
Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum, silver, tungsten, and zinc. The Climax mine near Leadville, Colorado was the largest producer of molybdenum in the world employing over 3,000 workers.