Arctic Cordillera
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| Arctic Cordillera | |
| Range | |
| Baffin Mountains at the northern end of Auyuittuq National Park
| |
| Country | Canada |
|---|---|
| Regions | Labrador, Baffin Island, Devon Island, Ellesmere Island, Axel Heiberg Island, Bylot Island |
| Highest point | Barbeau Peak |
| - elevation | 2,616 m (8,583 ft) |
| - coordinates | |
| Geology | Igneous, Metamorphic, Sedimentary |
The Arctic Cordillera, sometimes called the Arctic Rockies, are a vast deeply dissected mountain range in northeastern North America. It is the northermost mountain range in Canada, stretching from Ellesmere Island to the northernmost tip of Labrador. It offers some of the world's most spectacular scenery.[1] The cordillera is also one of Canada's two major ranges, the other being the Rocky Mountains of Western Canada.[2] Some of Canada's highest but least-known peaks are found within the cordillera,[1] including: Mount Asgard and Mount Thor.
The Arctic Cordillera runs along the eastern coast of Baffin Island. High-altitude mountains overlook the range with jagged peaks and ridges, though some flat-topped mountains exist. The Penny and Barnes ice caps are the largest ice caps on the island and have smoothly rolling terrain with no breaks in their coverage. North of the Penny ice cap, the mountain range becomes lower and narrower, disappears into Pond Inlet, and then returns on Bylot Island. Lying off the northeastern coast of Baffin Island, Bylot Island is almost completely covered in an ice cap, which is pierced by mountain peaks and ridges.
The Arctic Cordillera is a narrow ecozone compared to other Canadian ecozones. It borders the Northern Arctic, while the small segment within Labrador borders the Tiaga Shield.
Contents |
[edit] Geography and geology
The northern end of the Arctic Cordillera was uplifted during the Innuitian orogeny when the North American Plate moved northward during the mid Mesozoic. It contains igneous and metamorphic rocks, but for the most part is composed of sedimentary rocks. Mountains on Axel Heiberg Island consist mainly of long ridges of folded mid Mesozoic and Palaeozoic strata with minor igneous intrusions.
The Arctic Cordillera is younger than the Appalachians, and so erosion has not had time to reduce it to rounded hills. The mountains are also barren because trees can neither survive the extremely cold winter temperatures, nor grow during the short summers. Vast areas are covered by permanent ice and snow. The Arctic Cordillera resembles the Appalachians in composition and contain similar types of minerals. The mineral resources have not been greatly exploited, however, because the region's remote location makes development too costly when cheaper alternatives exist further south.
Mountains on southeastern Ellesmere Island are principally made of granitic gneiss, migmatic, undifferentiated intrusive and volcanic rocks. They are typified by being highly eroded, with conspicuous deep vertical fissures and narrow ledges.
Precambrian rock is the major component of the bedrock. The drier northern section is largely covered with ice caps while glaciers are common at the more humid southern end.
[edit] Volcanism
The mountains of volcanic rock range in age from 1.2 billion to 65 million years old.[2] The Late Cretaceous Ellesmere Island Volcanics has been uncertainly associated to both the early volcanic activity of the Iceland hotspot and the Alpha Ridge. Even though these volcanics are about 90 million years old, the volcanoes and cinder are still able to be seen.[3]
The Late Cretaceous Strand Fiord Formation is interpreted to represent the cratonward extension of the Alpha Ridge, a volcanic ridge that was active during the formation of the Amerasian Basin. The formation is part of the thick Sverdrup Basin succession and immediately precedes the final basin foundering event. The Strand Fiord volcanics are encased in marine strata and thin southward from a maximum thickness of 789+ m on northwestern Axel Heiberg to a zero edge near the southern shore of the island. Tholeiitic icelandite basalt flows are the main constituent of the formation with pyroclastic conglomerates, sandstones, mudrocks and rare coal seams are also present. The lava flows range in thickness from 6 to 60 m and subaerial flows predominate. Both pahoehoe and aa lava types are common and the volcanic pile accumulated mostly by the quiet effusion of lavas. The pyroclastic lithologies become more common near the southern and eastern edges of the formation and represent lahars and beach to shallow marine reworked deposits. The formation contains flood basalts which are found on western Axel Heiberg Island at Dragon Cliffs 300 meters tall. It contains columnar jointing units that are usually 1 to 3 meters in diameter.
The Bravo Lake Formation in central Baffin Island is a rare alkaline-suite that formed as a result of submarine rifting during the Paleoproterozoic period.[4] The lavas of the volcanic belt display geochemical characteristics similar to modern ocean-island-basalt groups. The range from moderately to intensely fractionated REE-profiles is similar to that from tholeiitic basalts to extremely alkaline lavas in Hawaii.[5]
[edit] Protected areas
More than one-fifth of Ellesmere Island is protected as Quttinirpaaq National Park (formerly Ellesmere Island National Park), which includes seven fjords and a variety of glaciers, as well as Lake Hazen, the world's largest lake north of the Arctic Circle. Barbeau Peak, the highest mountain in Nunavut (2,616 m, 8,593 ft) is located in the British Empire Range on Ellesmere Island. The most northern mountain range in the world, the Challenger Mountains is located in the northwest region of the island. The northern lobe of the island is called Grant Land. In July 2007, a study noted the disappearance of habitat for waterfowl, invertebrates, and algae on Ellesmere Island. According to John P. Smol of Queens University in Kingston, Ontario, and Marianne S. V. Douglas of the University of Alberta in Edmonton, warming conditions and evaporation have caused low water levels changes in the chemistry of ponds and wetlands in the area. The researchers noted that "In the 1980s they often needed to wear hip waders to make their way to the ponds...while by 2006 the same areas were dry enough to burn.[6]
Almost all of Baffin Island is within the Sirmilik National Park, harbouring large populations of thick-billed murres, Black-legged_Kittiwakes and greater snow geese. The park comprises three areas, Bylot Island, Oliver Sound and the Borden Peninsula.
The Auyuittuq National Park located on Baffin Island's Cumberland Peninsula, features the many terrains of Arctic wilderness, such as fjords, glaciers, and ice fields. In Inuktitut - the language of Nunavut's Aboriginal people, Inuit - Auyuittuq means "the land that never melts". Although Auyuittuq was established in 1976 as a national park reserve, it was upgraded to a full national park in 2000. Well known peaks in the park include Mount Asgard and Mount Thor with a 1,250 meter (4,100 foot), 105° face.
The Torngat Mountains National Park located on the Labrador Peninsula, covers much of the southern end of the Arctic Cordillera. It protects many of the Arctic wilderness, such as caribou, polar bears, peregrine falcon and the golden eagle. The park was first established on January 22, 2005, making it the first national park to be created in Labrador.
[edit] Glaciers and ice caps
Large portions of Ellesmere Island are covered with glaciers and ice, with Manson Icefield and Sydkap in the south; Prince of Wales Icefield and Agassiz Ice Cap along the central-east side of the island, along with substantial ice cover in Northern Ellesmere Island. The northwest coast of Ellesmere Island was covered by a massive, 500 km (300 mi) long ice shelf until the twentieth century. The Ellesmere ice shelf reduced by 90 percent in the twentieth century due to global warming, leaving the separate Alfred Ernest, Ayles, Milne, Ward Hunt, and Markham Ice Shelves.[7] A 1986 survey of Canadian ice shelves found that 48 square kilometres (19 sq mi) (3.3 km³, 0.8 cu mi) of ice calved from the Milne and Ayles ice shelves between 1959 and 1974.[8] The Ward Hunt Ice Shelf, the largest remaining section of thick (>10 m, >30 ft) landfast sea ice along the northern coastline of Ellesmere Island, lost 600 km (370 mi) of ice in a massive calving in 1961-1962.[9] It further decreased by 27% in thickness (13 m, 43 ft) between 1967 and 1999.[10] The breakup of the Ellesmere ice shelves has continued in the twenty-first century: the Ward Ice Shelf experienced a major breakup during summer 2002; [11] the Ayles Ice Shelf calved entirely on August 13, 2005; the largest breakoff of the ice shelf in 25 years, it may pose a threat to the oil industry in the Beaufort Sea. The piece is 66 square kilometres (25 sq mi).[12]
The Barnes icecap is found in the central part of the Baffin Island and it has been in retreat since at least the early 1960s when the Geographical Branch of the then Department of Mines & Technical Surveys sent a three-man survey team to the area to measure isostatic rebound and cross-valley features of the Isortoq River.
[edit] Climate
The Arctic Cordillera is one of Canada's most inhospitable climates. During winter, the temperature is nearly -35°C and it is very dark and long, while it is somewhat milder and more humid in the southernmost portions of the cordillera. Only about 1,050 people live in the region, found primarily in the communities of Clyde River and Qikiqtarjuaq (formerly known as Broughton Island). Most of the people who live in the region survive by hunting, fishing, and trapping.
Tree stumps were discovered in 1985 on Axel Heiberg Island dating back 40 million years, indicating this northerly part of the cordillera was warmer and wetter than its present-day climate.[13]
[edit] Flora and fauna
Not much can grow in the severe environment, where killing frost can come at any time during the year and even soil is rare. Three-quarters of the land is bare rock; and even lichen have a hard time of it. Trees are hardly noticeable. Plants that do grow in the region are mostly tiny species that often grow in thick isolating mats to protect themselves from the cold or are covered in thick hairs that help to insulate and to protect them from the harsh wind.
Some of the plant species found are arctic black spruce, arctic willow, cottongrass, kobresia, moss species, wood rush, wire rush, purple saxifrage, Dryas species, sedges, Diapensia, arctic poppy, mountain avens, mountain sorrel, river beauty, moss campion, bilberry, and arctic white heather.
The conditions here are far too severe for reptiles and amphibians to survive, and insects are also rare in the region. Muskoxen and barren-ground caribou are the only well-built herbivores in this environment, while polar bears and the arctic wolf are the only well-bulit carnivores to be found in the region. Smaller herbivores include the arctic hare and the collared lemming. Arctic foxes and stoats are some of the smaller carnivores found in the region. Marine mammals include narwhals, beluga whales, walrus, and ringed and bearded seals.
The furry-legged rock ptarmigan is a widespread bird in this desolate region. Typical birds of prey include the gyrfalcon and snowy owl. Some of the more widespread shore and seabirds are the thick-billed murre, black-legged kittiwake, ruddy turnstone, red knot, black guillemot, widespread ringed plover, little ringed plover and northern fulmar. Songbirds found in the Arctic Cordillera include the hoary redpoll, common redpoll, snow bunting, and lapland longspur. The snow goose, common and king eider, and red-throated loon are some species of waterfowl that live in the region.
[edit] Highest peaks
| Mountain/Peak | metres | feet | notes |
|---|---|---|---|
| Barbeau Peak | 2,616 | 8,583 | Highest point in eastern North America |
| Mount Whisler | 2,500 | 8,202 | Seconed highest point in eastern North America |
| Mount Oxford | 2,210 | 7,250 | |
| Commonwealth Mountain | 2,225 | 7,300 | |
| Outlook Peak | 2,210 | 7,251 | Highest point on Axel Heiberg Island |
| Mount Odin | 2,147 | 7,044 | Highest point on Baffin Island |
| Mount Asgard | 2,015 | 6,611 | |
| Qiajivik Mountain | 1,963 | 6,440 | Highest point in northern Baffin Island |
| Augilaaq Mountain | 1,951 | 6,401 | |
| Kisimngiuqtuq Peak | 1,905 | 6,250 | |
| Arrowhead Mountain | 1,860 | 6,102 | |
| Mount Eugene | 1,850 | 6,070 | |
| Ukpik Peak | 1,809 | 5,935 | |
| Mount Nukap | 1,780 | 5,840 | |
| Bastille Peak | 1,733 | 5,656 | |
| Mount Thule | 1,711 | 5,614 | |
| Angna Mountain | 1,710 | 5,610 | |
| Mount Thor | 1,675 | 5,500 | Features the Earth's greatest purely vertical drop |
[edit] Mountain ranges
The Arctic Cordillera is subdivided into numerous mountain ranges:
- Baffin Mountains
- Blackwelder Mountains
- Blue Mountains
- British Empire Range
- Bruce Mountains
- Byam Martin Mountains
- Challenger Mountains
- Cunningham Mountains
- Garfield Range
- Inglefield Mountains
- Kaumajet Mountains
- Krieger Mountains
- Precipitous Mountains
- Prince of Wales Mountains
- Princess Margaret Mountains
- Torngat Mountains
- Treuter Mountains
- Victoria and Albert Mountains
[edit] See also
[edit] References
- ^ a b Arctic Cordillera Terrestrial Ecozone Retrieved on 2007-09-26
- ^ a b Arctic Cordillera Ecozone Retrieved on 2007-09-26
- ^ Chris's journal entries Retrieved on 2007-08-05
- ^ Volcanology and geochemistry of the Bravo Lake Formation, Baffin Island, Nunavut. Retrieved on 2007-11-06
- ^ Central Baffin Island 4-D Project - Projects: Paleoproterozoic mafic magmatism in central Baffin Island. Retrieved on 2007-11-06
- ^ Northern Canada Ponds Drying Up
- ^ "Arctic Ice Shelf Broke Off Canadian Island" New York Times 30 December 2006
- ^ Jeffries, Martin O. Ice Island Calvings and Ice Shelf Changes, Milne Ice Shelf and Ayles Ice Shelf, Ellesmere Island, N.W.T.. Arctic 39 (1) (March 1986)
- ^ Hattersley-Smith, G. The Ward Hunt Ice Shelf: recent changes of the ice front. Journal of Glaciology 4:415-424. 1963.
- ^ Vincent, W.F., J.A.E. Gibson, M.O. Jeffries. Ice-shelf collapse, climate change, and habitat loss in the Canadian high Arctic. Polar Record 37 (201): 133-142 (2001)
- ^ NASA Earth Observatory. Breakup of the Ward Hunt Ice Shelf.
- ^ BBC News - Huge Arctic ice break discovered
- ^ ParkWardens: Arctic Cordillera Ecozone Overview Retrieved on 2007-11-08
[edit] Further reading
- Chernoff, M. N., H. R. Hovdebo, and J. Stuart-Smith. Eastern Canadian Cordillera and Arctic Islands An Aerial Reconnaissance. Ottawa: 24th International Geological Congress, 1972.
- Geological Survey of Canada. Cordillera and Pacific Margin Interior Plains and Arctic Canada. Geological Survey of Canada Current Research, 1998-A. 1998.
- Hall, John K. Arctic Ocean Geophysical Studies The Alpha Cordillera and Mendeleyev Ridge. Palisades, N.Y.: Lamont-Doherty Geological Observatory, Columbia University, 1970.
- Walker, Edward R. A Synoptic Climatology for Parts of the Western Cordillera. Montreal: McGill University, 1961.
