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TitleThe geology of Igloolik Island area and sea level changes
AuthorDredge, L A
SourceScience Institute of the Northwest Territories, Scientific Reports 2, 1992, 5 pages
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20090252
Mediapaper; on-line; digital
AreaMelville Peninsula; Igloolik Island; Hall Beach
Lat/Long WENS-82.0000 -81.0000 69.5000 69.2500
Subjectssurficial geology/geomorphology; marine geology; glacial history; glacial deposits; silts; gravels; sands; glacial landforms; glacial features; marine deposits; sea level changes; sea level fluctuations; radiocarbon dating; Cenozoic; Quaternary
Illustrationslocation maps; photographs; graphs; tables
AbstractMost of the geologic features on Igloolik Island and in the Hall Beach area developed during four main events in the earth's history: ancient marine flooding, glaciations, emergence of the land from the sea after ice ages, and the present day cold-climate.
Igloolik's geological heritage is tied to the sea. As early as 500 million years ago, what is now the island was part of an ancient sea bottom. Several times in the ancient past, it rose from the sea, only to be submerged again. The history of these very early events can be read in the rocks.
More recently, during the Ice Ages of the last 2 million years, the island and all nearby areas were covered by a massive ice sheet, perhaps 1 km thick. This ice sheet covered most of Canada. During the Ice Ages, glaciers and ice sheets grew and melted away a number of times. Each time the ice sheets grew, the tremendous weight of the ice depressed the crust of the earth beneath it (in the same way that finger-pressure on an inflated balloon will distort the balloon's surface). Each time the ice sheets melted, the crust slowly rebounded to its original shape. At Igloolik, the weight of the ice depressed the crust about 150 m, so that the whole island was below sea level. After the last of the ice sheets melted, the crust slowly rebounded, until Igloolik Island finally emerged from the sea. The earth materials on top of the bedrock tell the story of this passage of glaciers, and the final emergence of the island from the sea.
Between glaciations, Igloolik experienced climates similar to, or slightly warmer than, present. The present environment is probably an interglacial period, between the last ice age and the one to come.
The first people arrived on the Island about 4,000 years ago. They built their habitations along the coast, but their sites are now about 45 m above sea level. The location of the early habitations reflects continuing rise of the island from the sea, and changing coastal shapes.