Saint Elias Mountains

Saint Elias Mountains

Mt. Saint Elias
Highest point
Peak Mount Logan
Elevation 5,959 m (19,551 ft)
Coordinates 60°34′02″N 140°24′10″W / 60.56722°N 140.40278°W / 60.56722; -140.40278
Dimensions
Length 300 mi (480 km)
Width 90 mi (140 km)
Area 112,509 km2 (43,440 sq mi)
Geography

Saint Elias Mountains, east of the Wrangell Mountains

Countries United States and Canada
States/Provinces Alaska, Yukon and British Columbia
Range coordinates 60°30′N 139°30′W / 60.5°N 139.5°W / 60.5; -139.5Coordinates: 60°30′N 139°30′W / 60.5°N 139.5°W / 60.5; -139.5
Parent range Pacific Coast Ranges
Borders on Wrangell Mountains

The Saint Elias Mountains 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 USA 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 plate 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 stable 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 comprise 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. 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]

Ranges

The mountains are divided by the Duke Depression, with the shorter, more rounded Kluane Ranges to the east, and the higher Icefield Ranges to the west. Sub-ranges of the Saint Elias include the Alsek Ranges, the Fairweather Range, and the Centennial Range.[8]

Highest mountains

The highest mountains of the range include:

Mountain Height Location Notes
m ft
Mount Logan 5,959 19,551 Yukon Highest mountain in Canada
Mount Saint Elias 5,489 18,008 Alaska-YukonSecond highest in both Canada and the United States
Mount Lucania 5,226 17,147 Yukon #3 in Canada
King Peak 5,173 16,971 Yukon #4 in Canada
Mount Steele 5,073 16,644 Yukon #5 in Canada
Mount Bona 5,005 16,421 Alaska #5 in the United States
Mount Wood 4,842 15,885 Yukon
Mount Vancouver 4,812 15,787 Yukon
Mount Churchill 4,766 15,638 Alaska
Mount Slaggard 4,742 15,557 Yukon
Mount Macaulay 4,690 15,387 Yukon
Mount Fairweather 4,671 15,325 BC-Alaska #1 in BC[9]
Mount Hubbard 4,577 15,015 Yukon
Mount Bear 4,520 14,831 Alaska
Mount Walsh 4,507 14,787 Yukon
Mount Alverstone 4,439 14,565 Alaska-Yukon
University Peak 4,410 14,470 Alaska
McArthur Peak 4,389 14,400 Yukon
Mount Augusta 4,289 14,070 Alaska-Yukon
Mount Kennedy 4,250-4300 ~14,000 Yukon
Mount Cook4,196 13,766 Alaska-Yukon

Notes

  1. "Saint Elias Mountains". Geographic Names Information System. United States Geological Survey. Retrieved 2007-12-03.
  2. "Saint. Elias Mountains". BC Geographical Names. Retrieved 2013-12-27.
  3. Christeson, G.L.; Gulick, S.P.; van Avendonk, H.J.; Worthington, L.L.; Reece, R.S.; Pavlis, T.L. (2010). "The Yakutat terrane: Dramatic change in crustal thickness across the Transition fault, Alaska". Geology. 38: 895–898. doi:10.1130/G31170.1.
  4. Elliott, J.L.; Larsen, C.F.; Freymueller, J.T.; Motyka, R.J. (2010). "Tectonic block motion and glacial isostatic adjustment in southeast Alaska and adjacent Canada constrained by GPS measurements". Journal of Geophysical Research. 115: B09407. doi:10.1029/2009JB007139.
  5. 1 2 Finzel, E.S.; Trop, J.M.; Ridgway, K.D.; Enkelmann, E. (2011). "Upper plate proxies for flat-slab subduction processes in southern Alaska". Earth and Planetary Science Letters. 303: 348–360. doi:10.1016/j.epsl.2011.01.014.
  6. Plafker, G.; Berg, H.C. (1994). The Geology of Alaska. Boulder: Geological Society of America. pp. 389–449.
  7. Enkelmann, E.; Zeitler, P.K.; Pavlis, T.L.; Garver, J.I.; Ridgway, K.D. (2009). "Intense localized rock uplift and erosion in the St. Elias orogen of Alaska". Nature Geoscience. 2: 360–363. doi:10.1038/NGEO502.
  8. "Saint Elias Mountains". Bivouac.com. Retrieved 2013-03-15.
  9. Mount Fairweather is only partly in British Columbia. The highest peak entirely within British Columbia is Mount Waddington in the Coast Range, 4019 m (13186 ft).

References

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