Chilcotin Group

Predominantly, during Miocene and Pliocene times, a medium-sized volcanic field of overlapping vents occurred in British Columbia's Interior Plateau.

Prior to Late Pleistocene glacial erosion these centers formed a series of coalesced, low-profile shield volcanoes of unknown volume and distribution.

However, its morphology and geochemistry have been proven much similar to other volcanic plateaus such as the Snake River Plain in Idaho and parts of Iceland (Bevier, 1983).

This means that the Chilcotin is likely composed of many local volcanic vents, that were of small volumes that fed into the paleo-landscape, and subsequently are found in the major river systems that we see at present.

[2] Some centers erupted along pre-existing brittle fault systems while volcanism along its northern portion is most widely believed to have been related to a centre of upwelling magma called the Anahim hotspot (similar to that associated with present-day Hawaii), creating the Rainbow, Ilgachuz and Itcha Range shield volcanoes which also in turn form part of the Anahim Volcanic Belt.