Pegunungan Rocky

Rocky Mountains, atau sering disebut Rockies, merupakan rangkaian pegunungan yang memanjang di sebelah barat Amerika Utara. Panjangnya lebih dari 3 ribu mil (4.800 kilometer) membentang dari British Columbia, di Canada, sampai New Mexico, di Amerika Serikat. Puncak tertingginya adalah Gunung Elbert, di Colorado, kurang lebih 4.401 meter) diatas permukaan laut (dpl). Gunung Robson, berada pada ketingian 3.954 meter adalh puncak tertinggi di Canadian Rockies. Sistem Pegunungan Rocky Mountain termasuk kedalam United States physiographic region.

Daerah White Goat Wilderness, Alberta, Canada

Geografi and geologi

Teton Range di Taman Nasional Grand Teton, Wyoming

Pegunungan Rocky biasanya didefinisikan membentang dari Liard River di British Columbia, sampai ke Rio Grande di New Mexico. Pegunungan ini dapat juga dianggap membentang dari Alaska atau Mexico, namun pegunungan tersebut lebih dianggap sebagai bagian dari seluruh American cordillera daripada bagian dari Rockies.

Bagian termuda dari pegunungan Rocky terangkat semasa jaman Cretaceous akhir (140 juta-65 juta tahun yang lalu), meskipun sebagian pegunungan sebelah selatan terangkat pada jaman Precambrian (3.980 juta-600 juta tahun yang lalu). Kondisi geologinya terdiri dari kompleks batuan beku dan batuan metamorf; yang termuda adalah batuan sedimen (berada di sepanjang batas selatan pegunungan Rocky), dan batuan vulkanik dari jaman Tersier (65 juta-1.8 juta tahun yl.) berada di daerah Pegunugan San Juan dan di beberapa daerah lain. Millennia of severe erosion in the Wyoming Basin transformed intermountain basins into a relatively flat terrain. The Tetons and other north-central ranges are magnificent granitic intrusions of folded and faulted rocks of Paleozoic and Mesozoic age (Peterson 1986; Knight 1994).

Periods of glaciation occurred from the Pleistocene Epoch (1.8 million-70,000 years ago) to the Holocene Epoch (fewer than 11,000 years ago). Recent episodes included the Bull Lake Glaciation that began about 150,000 years ago and the Pinedale Glaciation that probably remained at full glaciation until 15,000-20,000 years ago (Pierce 1979). Ninety percent of Yellowstone National Park was covered by ice during the Pinedale Glaciation (Knight 1994). The "little ice age" was a period of glacial advance that lasted a few centuries from about 1550 to 1860. For example, the Agassiz and Jackson glaciers in Glacier National Park reached their most forward positions about 1860 during the little ice age (Grove 1990).

Water in its many forms sculpted the present Rocky Mountain landscape (Athearn 1960). Runoff and snowmelt from the peaks feed Rocky Mountain rivers and lakes with the water supply for one-quarter of the United States. The rivers that flow from the Rocky Mountains eventually drain into three of the world's five Oceans: the Atlantic Ocean, the Pacific Ocean, and the Arctic Ocean. These rivers include:

Peta yang menunjukkan lokasi pegunungan Rocky.

• Arkansas River
• Athabasca River
• Colorado River
• Columbia River
• Fraser River
• Kootenay River
• Missouri River
• Peace River
• Platte River
• Rio Grande
• Saskatchewan River
• Snake River
• Yellowstone River

The Continental Divide is located in the Rocky Mountains and designates the line at which waters flow either to the Atlantic or Pacific Oceans. Triple Divide Peak (8020 feet/2444 m) in Glacier National Park (US) is so named due to the fact that water which falls on the mountain reaches not only the Atlantic and Pacific, but the Arctic Ocean as well.

Sejarah Manusia

Since the last great Ice Age, the Rocky Mountains were a sacred home first to Paleo-Indians and then to the Native American tribes of the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Crow. Flathead, Shoshoni, Sioux, Ute, and others (Johnson 1994). Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains. Like the modern tribes that followed them, Paleo-Indians probably migrated to the plains in fall and winter for bison and to the mountains in spring and summer for fish, deer, elk, roots, and berries. In Colorado, along the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400-5,800 years (Buchholtz 1983). A growing body of scientific evidence indicates that Native Americans had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning (Kay 1994).

Recent human history of the Rocky Mountains is one of more rapid change (Lavender 1975; Knight 1994). The Spanish explorer Francisco Vásquez de Coronado--with a group of soldiers, missionaries, and African slaves--marched into the Rocky Mountain region from the south in 1540. The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed the Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture.

Berkas:Rockies USA1.jpg

Colorado Rockies

The Lewis and Clark expedition (1804-1806) was the first scientific reconnaissance of the Rocky Mountains. Specimens were collected for contemporary botanists, zoologists, and geologists (Jackson 1962). The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels.

Mountain men, primarily French, Spanish, and British roamed the Rocky Mountains from 1720 to 1800 seeking mineral deposits and furs. After 1802, American fur traders and explorers ushered in the first widespread white presence in the Rockies. The more famous of these include Americans included William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith. On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using Wyoming's South Pass.

The Mormons began to settle near the Great Salt Lake in 1847. In 1859, gold was discovered near Cripple Creek, Colorado, and the regional economy of the Rocky Mountains was changed forever. The transcontinental railroad was completed in 1869, and Yellowstone National Park was established in 1872. While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. President Harrison established several forest reserves in the Rocky Mountains in 1891-1892. In 1905, President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park (Buchholtz 1983). Economic development began to center on mining, forestry, agriculture, and recreation, as well as on the service industries that support them (Lavender 1975). Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities.

Referensi

• Athearn, R. G. 1960. High country empire: the High Plains and Rocky Mountains. McGraw-Hill, New York. 358 pp.
• Brandt, E. 1993. How much is a gray wolf worth? National Wildlife 31:4­12.
• Buchholtz, C. W. 1983. Rocky Mountain National Park: a history. Colorado Associated University Press, Boulder. 255 pp.
• Grove, J. M. 1990. The little ice age. Rutledge Press, New York. 498 pp.
• Jackson, D. 1962. Letters of the Lewis and Clark expedition with related documents 1783­1854. University of Illinois Press, Urbana. 728 pp.
• Kay, C. E. 1994. Aboriginal overkill. Human Nature 5:359­398.
• Lavender, D. 1975. The Rockies. Harper and Row, New York. 433 pp.
• Knight, D. H. 1994. Mountains and plains: the ecology of Wyoming landscapes. Yale University Press, New Haven, Conn. 338 pp.
• Peterson, J. A., editor. 1986. Paleotectonics and sedimentation in the Rocky Mountain Region, United States. Memoir 41, American Association of Petroleum Geologists. Tulsa, Okla. 693 pp.
• Pierce, K. L. 1979. History and dynamics of glaciation in the northern Yellowstone National Park area. Professional Paper 729-F. U.S. Geological Survey, Washington, D.C. 90 pp

Pranala luar

• USGS Biology web site about Rocky Mountains (public domain source)]
• U.S. Geological Survey website on the Rocky Mountains
• Blue Planet Biomes - Rocky Mountains
• Rocky Mountain National Park - National Parks Gallery