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10 de jun. de 2024 · The Rocky Mountains, formed over millions of years through the dramatic geological processes of the Laramide Orogeny, are not just a geological marvel. They are also home to a vibrant and diverse ecosystem shaped by the unique environmental conditions of this high-altitude landscape.
- Overview
- Physiography
The Rocky Mountains of North America, or the Rockies, stretch from northern Alberta and British Columbia in Canada southward to New Mexico in the United States, a distance of some 3,000 miles (4,800 kilometres). In places the system is 300 or more miles wide.
What types of minerals are found in the Rocky Mountains?
The Rocky Mountains are noted for their many deposits of copper, silver, gold, lead, zinc, molybdenum, beryllium, and uranium. Sapphires and other nonmetallic mineral deposits include phosphate rock, potash, trona, magnesium and lithium salts, Glauber’s salt, gypsum, limestone, and dolomite.
When were the Rocky Mountains settled?
The human presence in the Rocky Mountains has been dated to between 10,000 and 8,000 BCE. First Nations and Native American peoples still inhabiting the northern ranges of the Rocky Mountains in modern times include the Shuswap and Kutenai of British Columbia, Coeur d’Alene and Nez Percé of Idaho, and Salish of Montana. The traditional lands of the Shoshone in Idaho and Wyoming and the Ute in Utah and Colorado extended into the west-central ranges. Southwestern groups include the Hopi and other Pueblo Indians and the Navajo.
Rocky Mountains, mountain range forming the cordilleran backbone of the great upland system that dominates the western North American continent. Generally, the ranges included in the Rockies stretch from northern Alberta and British Columbia southward to New Mexico, a distance of some 3,000 miles (4,800 km). In places the system is 300 or more miles wide. Limits are mostly arbitrary, especially in the far northwest, where mountain systems such as the Brooks Range of Alaska are sometimes included. The Rockies are bordered on the east by the Great Plains and on the west by the Interior Plateau and Coast Mountains of Canada and the Columbia Plateau and Basin and Range Province of the United States.
The Canadian Rockies include the Mackenzie and Selwyn mountains of the Yukon and Northwest Territories (sometimes called the Arctic Rockies) and the ranges of western Alberta and eastern British Columbia. The Northern Rockies include the Lewis and Bitterroot ranges of western Montana and northeastern Idaho. These ranges formed along the eastern edge of a region of carbonate sedimentation some 17 miles (27 km) thick, which had accumulated from the late Precambrian to early Mesozoic time (i.e., between about 1 billion and 190 million years ago). This structural depression, known as the Rocky Mountain Geosyncline, eventually extended from Alaska to the Gulf of Mexico and became a continuous seaway during the Cretaceous Period (about 145 to 66 million years ago). The ranges of the Canadian and Northern Rockies were created when thick sheets of Paleozoic limestones were thrust eastward over Mesozoic rocks during the mountain-building episode called the Laramide Orogeny (65 to 35 million years ago). Some of these thrust sheets have moved 20 to 30 miles (32 to 48 km) to their present positions. The western margin of the Canadian Rockies and Northern Rockies is marked by the Rocky Mountain Trench, a graben (downfaulted, straight, flat-bottomed valley) up to 3,000 feet (900 metres) deep and several miles wide that has been glaciated and partially filled with deposits from glacial meltwaters.
The Columbia Icefield is situated on the continental divide in the Canadian Rockies at elevations of 10,000 to 13,000 feet (3,000 to 4,000 metres) above sea level. It includes the large Athabasca Glacier, which is nearly five miles long and about a mile wide. Glaciers in this ice field, while continuing to move, are thinning and retreating. The Canadian Rockies are about equally divided between drainage to the east (Atlantic and Arctic oceans) and west (Pacific Ocean).
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The Middle Rockies include the Bighorn and Wind River ranges in Wyoming, the Wasatch Range of southeastern Idaho and northern Utah, and the Uinta Mountains of northeastern Utah; the Absaroka Range, extending from northwestern Wyoming into Montana, serves as a link between the Northern and Middle Rockies. While the massive deposition of carbonates was occurring in the Canadian and Northern Rockies from the late Precambrian to the early Mesozoic, a considerably smaller quantity of clastic sediments was accumulating in the Middle Rockies. Mountain building there resulted from compressional folding and high-angle faulting, except for the low-angle thrust-faulting in southwestern Wyoming and southeastern Idaho. The granitic core of the anticlinal mountains often has been upfaulted, and many ranges are flanked by Paleozoic sedimentary rocks (e.g., shales, siltstones, and sandstones) that have been eroded into hogback ridges. This same mountain-building process is occurring today in the Andes Mountains of South America. Most mountain building in the Middle Rockies occurred during the Laramide Orogeny, but the mountains of the spectacular Teton Range attained their height less than 10 million years ago by moving more than 20,000 vertical feet relative to the floor of Jackson Hole along an east-dipping fault.
The Bighorn, Wind River, and Uinta ranges all form sharp ridge lines that rise above surrounding basins. The Wind River Range supports a large area of glaciers, including Dinwoody Glacier. These glaciers, however, are retreating fairly rapidly.
At about 285 million years ago, a mountain building processes raised the ancient Rocky Mountains. This ancient mountain range was much smaller than the modern Rockies, only reaching up to 2,000 feet high and stretching from Boulder to Steamboat Springs, Colorado.
26 de jun. de 2024 · The Rocky Mountains were formed through a series of geological processes that took place millions of years ago. The primary event responsible for their creation is known as the Laramide Orogeny, which occurred approximately 75 million years ago during the Cenozoic era.
The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces. The oldest rock is Precambrian Wyoming craton that forms the core of the North American continent. The Wyoming Craton originated as a 100,000 km 2 middle Archean craton that was modified by late Archean volcanic magmatism and plate ...
The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces. The oldest rock is Precambrian metamorphic rock that forms the core of the North American continent. There is also Precambrian sedimentary argillite, dating back to 1.7 billion years ago.
The Rocky Mountains were formed in a complex way, mainly because of the way the Earth’s plates crashed and slid under each other, a process known as subduction. This caused big changes in the Earth’s surface, including the creation of mountains.
