Geology of British Columbia

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Sydney Cannings. Geology of British Columbia

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GEOLOGY of BRITISH COLUMBIA

A Journey through Time

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MAP 4. EARLY DEVONIAN (395 million years ago). The westward travel of the Arctic terranes towards Panthalassa (the precursor to the Pacific Ocean) is believed to have been propelled by a Caribbean-style subduction zone. This subduction zone, its island arcs and continental fragments travelled rapidly along a Paleozoic Northwest Passage.

MAP 5. LATE DEVONIAN–MISSISSIPPIAN (360 million years ago). The northward shift of Euramerica (the now-combined Laurentia and Baltica), during its collision with Gondwana, results in the formation of a subduction zone along the west coast. This subduction begins from the small Caribbean-type zone and moves some of the Arctic terranes southward. The hot upwelling beneath the subduction zone causes a rift in Laurentia, giving birth to the first of the peri-Laurentian arc terranes along the west coast, including the Yukon-Tanana terrane (blue-green).

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