Saint Elias Mountains

Saint Elias Mountains
Mt Saint Elias.jpg
Mt. Saint Elias
Highest point
PeakMount Logan
Elevation5,959 m (19,551 ft)
Coordinates60°34′02″N 140°24′10″W / 60°34′02″N 140°24′10″W / 60.56722; -140.40278
Dimensions
Length300 mi (480 km)
Width90 mi (140 km)
Area112,509 km2 (43,440 sq mi)
Geography
Wrangell Mountains.jpg
Saint Elias Mountains, east of the Wrangell Mountains
CountriesUnited States and Canada
States/ProvincesAlaska, Yukon and British Columbia
Range coordinates60°30′N 139°30′W / 60°30′N 139°30′W / 60.500; -139.500
Parent rangePacific Coast Ranges
Borders onWrangell Mountains

The Saint Elias Mountains (French: Chaîne Saint-Élie) are a subgroup of the Pacific Coast Ranges, located in southeastern Alaska in the United States, Southwestern Yukon and the very far northwestern part of British Columbia in Canada. The range spans Wrangell-St. Elias National Park and Preserve in the United States and Kluane National Park and Reserve in Canada and includes all of Glacier Bay National Park in Alaska. In Alaska, the range includes parts of the city/borough of Yakutat and the Hoonah-Angoon and Valdez-Cordova census areas.[1]

This mountain range was named after Mount Saint Elias which had been named in 1741 by the Danish explorer Vitus Bering.[2]

Geology

The St. Elias Mountains is the highest coastal mountain range on Earth. It formed due to the subduction of the Yakutat microplate underneath the North American Plate. The Yakutat microplate is a wedge shaped oceanic plateau with 20–30 km thickness.[3] Similar to the adjacent Pacific plate (7 km crustal thickness) the Yakutat plate is currently moving northwestward with a rate of ~50 mm/year with respect to North America.[4] The Yakutat plate is transported northwards along the active Fairweather Fault, which probably started more than 35 million years ago.[5] Due to its thickness the Yakutat plate is buoyant resulting in surface uplift of the overriding North American plate, which formed the Talkeetna Mountains and the Alaska Range in southcentral Alaska located above the subducted part of the Yakutat plate.[5]

The St. Elias Mountains formed at the plate boundary between the Yakutat and North American plate. The up to 12 km thick sediments that have been deposited on top of the Yakutat plate are imbricated and deformed as they became scraped off and compose today the southern (coastal) flanks of the St. Elias Mountains. In contrast the high elevated regions of the drainage divide ( Bagley Ice Field, Seward Glacier) and north of it are composed of rocks that are part of the North American plate.[6] The highest peaks of the St. Elias Mountains are located in the high ice field region of the Kluane National Park (Mt. Logan, Mt. Vancouver) and north of the Malaspina Glacier (Mt. St. Elias, Mt. Cook), in the region known as the St. Elias syntaxis. At the syntaxis region the tectonic style changes from strike-slip motion along the Fairweather Fault to collision west of Malaspina Strait. This tectonic transition concentrates stress in the crust at the syntaxis that together with efficient glacial erosion results in positive feedback processes that through time forms extreme high mountain peaks and local relief, and rapid exhumation of rocks from up to 10 km depths to the surface.[7]

Other Languages