Bella Bella and Gale Passage dike swarms

Map showing the location of an east–west trending zone of related volcanoes extending from the British Columbia Coast to the Interior.
The extent of the Anahim Volcanic Belt, including the Bella Bella and Gale Passage dike swarms

The Bella Bella and Gale Passage dike swarms are two parallel dike swarms on the Central Coast of British Columbia, Canada.[1] They range in age from 14.5 to 12.5 million years old.[1][2] They are both chemically bimodal, consisting of rocks such as basalt, trachyte and comendite. They form the westernmost extent of the Anahim Volcanic Belt on Athlone Island, Dufferin Island and Denny Island.[3]

The Bella Bella and Gale Passage dike swarms are petrographically similar to the shield complexes in the central Anahim Volcanic Belt. As a result, the swarms are thought to represent the roots of a peralkaline magma system in which they are the magma conduits connecting the underlying magma chamber to the volcanic centre at the surface, which has been extensively eroded to remnants of eruptive breccia.[3]

References

  1. ^ a b Ernst, Richard E.; Kenneth L. Buchan (June 2001). Mantle Plumes: Their Identification Through Time (Special Paper (Geological Society of America)). Geological Society of America. p. 261. ISBN 978-0-8137-2352-5.
  2. ^ Dewit, Megan (2014). "The geothermal potential of Nazko Cone, British Columbia" (Document). Simon Fraser University. p. 4.
  3. ^ a b Souther, J. G. (1986). "The western Anahim Belt: root zone of a peralkaline magma system". Canadian Journal of Earth Sciences. 23 (6). NRC Research Press: 895–908. Bibcode:1986CaJES..23..895S. doi:10.1139/e86-091.


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