Coast Range Arc

Image of the Pacific Northwest. Red indicates the inferred boundaries of the Coast Range Arc.

The Coast Range Arc was a large volcanic arc system, extending from northern Washington through British Columbia and the Alaska Panhandle to southwestern Yukon.[1] The Coast Range Arc lies along the western margin of the North American Plate in the Pacific Northwest of western North America. Although taking its name from the Coast Mountains, this term is a geologic grouping rather than a geographic one, and the Coast Range Arc extended south into the High Cascades of the Cascade Range, past the Fraser River which is the northward limit of the Cascade Range proper.

The Coast Range Arc formed as a result of subduction of the Kula and pre-existing Farallon Plates. It is most famous for being the largest single body of granitic rock in North America,[2] which is usually referred to as the Coast Plutonic Complex or the Coast Mountains Batholith. It is a coast-parallel continental volcanic arc similar to the Andes of South America and the largest continental volcanic arc fossil in the world.[3]

  1. ^ Stowell, Harold H.; McClelland William C. (January 2000). Tectonics of the Coast Mountains, Southeastern Alaska and British Columbia. Geological Society of America. p. 101. ISBN 0-8137-2343-4. Retrieved 2008-09-04.
  2. ^ Cite error: The named reference SI was invoked but never defined (see the help page).
  3. ^ "Formation of new continental crust in Western British Columbia during transpression and transtension" (PDF). Carlson R.W. Archived from the original (PDF) on 2012-02-12. Retrieved 2008-09-04.