Islands of the Canadian Arctic
Situated off the northern coast of mainland
Canada, and located almost entirely within the Arctic Circle, lies one of the Earth's largest groups of islands —
a group known as the Arctic Archipelago. With a combined land area of some 1.4 million km² there are 36,563 islands
in total, arranged in a vast triangular formation measuring some 2,350 km from east to west and 1,900 km from north to
south.
Much of continental Canada lies upon a basement of ancient and stable Precambrian rock formations known as the Canadian Shield. North and west of the shield lie two great geological formations: the Arctic Platform (dominated by sedimentary rock formations) and the Innuitian Orogen (dominated by highly deformed sedimentary and volcanic rocks). To the southeast, outside of the Arctic Circle lies a second platform structure known as the Hudson Bay Platform, comprising a vast depression filled by the shallow waters of Hudson Bay. The Canadian Shield itself also underlies a major portion of this region: known as the Churchill Province, it sweeps across the eastern edge of the Arctic Archipelago and comprises most of Baffin Island and the eastern sections of both Devon Island and Ellesmere Island. It also underlies the Boothia and Melville peninsulas of the mainland and the western portions of Somerset Island.
The mainly low-lying islands found immediately off the northern coast of Canada include some of the Arctic's largest islands: Banks Island (70,028 km²), Victoria Island (217,291 km²), Baffin Island (507,451 km²) and Prince of Wales Island (33,339 km²). With the exception of Baffin Island they lie predominantly upon the Arctic and Hudson platforms. They are bound by the Beaufort Sea on the west and by the Davis Strait and Baffin Bay on the east — the latter both being extensions of the Atlantic Ocean. On their southern margins they are separated from the Canadian mainland by a series of channels and straits: (from west to east) the Dolphin & Union Strait, the Coronation Gulf, the Dease Strait, the Queen Maud Gulf, the Bellot Strait (just 2 km in width), the Fury & Hecla Strait and the Hudson Strait.
The second major grouping of islands are those that form the Queen Elizabeth Islands, penetrating high into the Arctic. They are separated from the southern islands by a broad channel that stretches for over 1,200 km from east to west. The channel has no individual name but rather includes several named bodies of water: the McClure Strait, the Viscount Melville Sound, the Parry Channel and the Lancaster Sound. The eastern side of the group is separated from Greenland by the Nares Strait. In addition to numerous minor islands, the Queen Elizabeth Islands also include some of the Arctic's major landmasses: Ellesmere Island (196,236 km²), Devon Island (55,247 km²), Axel Heiberg Island (43,178 km²) and Melville Island (42,149 km²). These islands are mainly of the Innuitian Orogen formation and are characterised by a mix of eroded upland plateau and tall mountain ranges.
The landscape of the Arctic has been heavily shaped by periods of glaciation and deglaciation. The most recent of these was the Wisconsin occurring between 25,000 and 10,000 years ago — at its peak its Laurentide and Cordillera ice sheets covered much of North America in ice of up to 4 km in thickness. The advance and retreat of these ice sheets has created a geologically young, post-glacial landscape of eroded plains with extensive deposits of loosely compacted glacial materials, scoured rocks and a profusion of meltwater lakes and streams. In the north and east the more erosion-resistant rocks have been been sculpted into the sharp-peaked mountain ranges of Baffin Island, Axel Heiberg Island and Ellesmere Island. Today, all that remains of the ice sheets are the small ice caps found on Baffin Island (Penny and Barnes ice caps), Axel Heiberg Island (Franz Muller Ice Cap and Steacie Ice Cap), Ellesmere Island (Prince of Wales Ice Cap, the Sydkap Ice Cap, the North Ellesmere Ice Cap, the Manson Ice Cap, and the Agassiz Ice Cap) and Devon Island (Devon Island Ice Cap). Minor ice caps are also found on Melville Island and Meighen Island. All are currently in a state of retreat.
Topographically, the most striking feature of the Arctic Archipelago is the mountain range known as the Arctic Cordillera, a range that extends for some 1,300 km northwestwards from the Torngat Mountains on the fringes of the Labrador Peninsula, in the southeast, through eastern Baffin Island and across much of Ellesmere Island in the northwest. Reaching 2,156 m above sea level on Baffin Island, 1,905 m on Bylot Island and 2,616 m at Barbeau Peak in the British Empire Range of Ellesmere Island, these mountains are characterised by ice caps, deep glacier-filled valleys and by sharp peaks and ridges.
