Origin
The source of the Anahim hotspot is a matter of controversy. Some geologists hypothesize that the Anahim hotspot is linked with an upper mantle plume (miniplume) rather than the more common deep mantle plume because of the small size of the Bella Bella and Gale Passage dike swarms. Others prefer to attribute the hotspot to tensional cracking of the lithosphere above the northern edge of the subducting Juan de Fuca and Explorer plates at the Cascadia subduction zone or interpreted as an edge effect of the subducting plates in the mantle. None of the hypotheses so far suggested is without critics. Part of the controversy is due to the rather sudden appearance of the hotspot in the geologic record. A number of hotspot models have been suggested to explain tensional cracking origins, however. Some of Earth's more prominent hotspots were unified along with flood basalt volcanism and continential rifting. While mafic lava flows appear to merge laterally with the less silicon-undersaturated lavas of the Chilcotin Group surrounding the Anahim Volcanic Belt, the particular nature and connection between the Anahim hotspot and the Chilcotin Group is unknown. Volcanic chemistry and isotopic composition of the Anahim Volcanic Belt do not distinguish between either a rift or a hotspot setting.
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