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出典:『Wikipedia』 (2010/12/02 09:27 UTC 版)

英語による解説

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The Crowsnest Formation, also called the Crowsnest Volcanics, is a well-known outcroping of volcanic rock in southwestern Alberta, Canada. These volcanics were formed about 100 million years ago during the Cretaceous period and is estimated to cover a volume of 209 km³ (50 cu mi). These volcanics are older than the Rocky Mountains and are essentially the eroded remnants of an alkaline volcanic center that was erupted in a fluvial environment.