Lying north of mainland Canada, the Arctic Archipelago consists of 94 major islands (greater than 130 km2) and 36 469 minor islands covering 1.4 million km2.
Lying north of mainland Canada, the Arctic Archipelago consists of 94 major islands (greater than 130 km2) and 36 469 minor islands covering 1.4 million km2. Apart from Greenland, which is almost entirely ice-covered (and geologically an extension of the archipelago), the Canadian Arctic Archipelago forms the world's largest high-arctic land area. It contains six of the world's 30 largest islands; Baffin Island (fifth) is larger than the United Kingdom. They are separated by "channels," some of which would qualify as seas elsewhere in the world. Parry Channel runs from Lancaster Sound to McClure Strait and divides the northern Queen Elizabeth Islands from the rest, and is an important part of the Northwest Passage. The largest islands are Baffin, Victoria, Ellesmere, Banks, Devon, Axel Heiberg, Melville and Prince of Wales.
Physical Geography and Geology
The major islands in the eastern Arctic (Baffin, Devon, Ellesmere, Axel Heiberg) are mountainous, with peaks over 2000 m. The higher land on these islands is commonly occupied by Ice Caps that contain most (75%) of the glacier ice and the largest Glaciers in Canada, and one-third of the volume of land ice worldwide, not including the ice found on Greenland and Antarctica. These highland areas were the major source area for the Innuitian ice sheet during the last Glaciation. These eastern islands contain the northern extent of the Canadian Shield, which is covered in areas by fairly flat-lying Palaeozoic rocks. The northern and western regions, including most of the Queen Elizabeth Islands, consists of younger, heavily folded sedimentary rocks, producing mountains on Axel Heiberg and parts of Devon and Ellesmere Islands. The central and western islands are generally flat with low relief (less than 200 m), and consist of sedimentary rocks of the Arctic Platform.
This geological variety produces spectacular variations in scenery, with rugged mountains, steep-sided fiords, and high and low plains of various ages and rock types. The Shield areas likely contain mineral deposits (including gold and diamonds), while oil and natural gas deposits have been found in areas of sedimentary rocks, such as the Sverdrup Basin. Coal is also found in these areas, and was discovered by early European explorers.
Climate and Climate Change
By any measure, this is a truly polar environment. On the northern islands, night lasts three or four months in winter and day lasts the same period in summer. The average annual temperature may be as low as -20ºC in the north and -6ºC in southern Baffin Island, with extreme low temperatures in the order of -50ºC. In the high arctic islands, summer temperatures may rise above freezing for only one or two months. Annual precipitation is low, ranging from 400 mm on southern Baffin Island to less than 100 mm on central Ellesmere Island. The Queen Elizabeth Islands are a polar desert, with less than 150 mm of precipitation a year. The cold climate has led to the development of Permafrost, which underlies all of the land area and exceeds 550 m in thickness in many places. Only a thin (less than 1 m) active layer melts at the surface each summer.
Predicted Climate Change will occur earliest and most intensely in high-latitude areas, and changes have already been noticed in the High Arctic. Annual mean temperatures are predicted to increase by 3-7ºC over the coming century, with the greatest warming to occur in winter (as much as 14ºC). In addition to warmer winter temperatures, precipitation could increase greatly. Summer temperatures and precipitation are also expected to increase strongly.
Trees are absent on the archipelago, and the Tundra vegetation consists of dwarf shrubs, forbs, sedges and grasses, mosses and lichens. In the northern islands, woody plant species become less prominent, and vegetation is sparse except in some lowland areas (polar oases) where the microclimate is warmer and there is greater snow accumulation. There are only about 200 vascular plant species, 200-300 species each of bryophytes and lichens on the arctic islands. Many plant species are widespread and have a circumpolar distribution.
Only 19 species of land mammals live on the archipelago, generally in small numbers restricted to certain areas. The high arctic islands are home to Peary caribou that are smaller and lighter in colour than the barren-ground caribou; they do not migrate like their mainland cousins. Other mammals in the archipelago include the muskox, arctic fox, wolf, lemming and arctic hare. Sixty-four species of birds spend the summer in the high arctic islands and only 6 species overwinter there. The surrounding seas are home to the polar bear, the walrus and various types of seal and whale, including the narwhal and the beluga.
Terrestrial arthropods are important components of the high-arctic tundra, and 381 species have been named from the archipelago: of these, 64% are insects, 20% are mites and 12% are springtails. These proportions of known arthropods are notably different from southern Canadian ecosystems where insects are 90%, mites are 6% and springtails are 1% of the total known species
The High Arctic has been occupied by the Inuit and their predecessors for most of the past 4000 years, and today they live in coastal settlements scattered throughout the islands. The most northerly community in Canada is Grise Fjord on southern Ellesmere Island, which was created in 1953 when the Canadian government relocated people from Port Harrison (now Inukjuak), Qué. Ancient links with the Greenlandic people are still maintained. Evidence has been found of contact between the Vikings, who lived in Greenland during the Middle Ages, and the islands (see Norse voyages). The non-Inuit population is generally made up of government and military personnel in communities such as Iqaluit , Cambridge Bay, Resolute and the military station at Alert.
PETER ADAMS Rev: GREG H.R. HENRY
Arctic Archipelago Channels
The seawaters of the Arctic Archipelago were first sighted by William Baffin, who sailed into Smith Sound and northern Baffin Bay in 1616 and who first recorded Jones Sound and Lancaster Sound, which is the eastern entrance to the Northwest Passage. In 1819 Sir William Parry sailed through the west as far as McClure Strait, where he was stopped by ice. The Northwest Passage was finally sailed by Roald Amundsen in 1903-06 and again by Sergeant Henry Larsen of the RCMP in 1940-42 (west-east) and 1944 (east-west). The waters north of Baffin Bay, now known as Nares Strait, were explored from 1852 on.
Very little scientific Oceanography was done in the Arctic Islands until after the Second World War, although an excellent pioneer expedition under Otto Sverdrup in 1898-1902 produced important geological and biological results. Danish expeditions and the US Coastguard vessel Marion in 1928 made oceanographic studies in Smith, Jones and Lancaster Sounds.
The depths of the channels range from less than 200 m to about 800 m in eastern Lancaster Sound. The most important sill (minimum) depths, related to water transport, are 140 m in Barrow Strait and 250 m in Nares Strait. The Continental Shelf varies from over 550 m in depth in the west and north to 200 m in the east. In spite of low tidal ranges, which decrease from east to west, tidal currents can be strong in certain narrow passages, such as Bellot Strait , Fury and Hecla Strait and Hell Gate.
The dominant water flow through the islands is from the Arctic Ocean southward through Nares Strait and eastward through Lancaster Sound and Fury and Hecla Strait. The first 2 currents flow into Baffin Bay and the latter into Foxe Basin, Hudson Bay and Hudson Strait . The most recent estimate of the total transport of Arctic Ocean water through the islands is 2.1 million m3/s, but there is probably considerable annual variation. The depth and extent of the channels offer commercial possibilities (for submarine tankers) as well as some strategic concern (as an avenue of approach for submarines).
Ice cover, with an average thickness from 1.6 m to 2 m, is complete in winter throughout the archipelago, with the exception of several recurring polynyas (areas of open water surrounded by sea ice), the largest of which are in northern Baffin Bay and in the southeastern Beaufort Sea. These polynyas, which freeze late and thaw early, are a focus for marine and bird life. There is evidence of early human habitation, by the Thule and Dorset peoples, on the landmasses adjoining them.
Biologically, the waters of the archipelago are rich in mammals and birds (in summer) and poor in fishes. The plankton is typical of that of the upper 250 m of the Arctic Ocean.