Duluth Complex

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The Duluth Complex is the basement bedrock beneath the Arrowhead Region of northeastern part of the U.S. state of Minnesota, including the eastern part of Superior National Forest and the Boundary Waters Canoe Area Wilderness (BWCA). In geological terms, it is a massive Keweenawan intrusion, formed about 1,100 million years ago (mya) when the North American craton began to split apart in the Midcontinent Rift.[1] The complex is composed primarily of gabbro, with significant amounts of anorthosite and other granitic rocks.[2][3] The Duluth Complex extends north and east from Duluth to the Canadian border and includes the Misquah Hills.

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[edit] Notes

  1. ^ Ojakangas, Richard W.; Charles L. Matsch (1982). Minnesota's Geology, Illus. Dan Breedy, Minneapolis, Minnesota: University of Minnesota Press. ISBN 0-8166-0953-5. 
  2. ^ Minnesota Geological Survey. Mineral potential and geology of the Duluth Complex. University of Minnesota. Retrieved on March 22, 2007.
  3. ^ United States Geological Survey. America's Volcanic Past - Minnesota. Retrieved on March 22, 2007.
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