Anahim Volcanic Belt.
Geologists define a hot spot as a source of volcanism independent of tectonic plate boundaries. Hot spots commonly create a chain of volcanoes as the plate moves above them. Hawaii, Iceland, and Galapagos are well-known examples.
North America has two proposed continental hot spots – the Yellowstone hot spot in Wyoming and the much-less-studied Anahim hot spot at the northern edge of the Chilcotin region. The surface traces of both of these hot spot tracks are consistent with one another, revealing a direction of movement for the North American plate of ~250 degrees at a rate of 2-3 cm per year.
The trace of the Anahim hot spot – the Anahim Volcanic Belt – stretches more than 300 km from Bella Bella in the west to Nazko Cone near Quesnel in the east. The youngest formations are at Nazko Cone, which erupted ~7200 BP and is presumably the present location of the hot spot. The central segment of the AVB includes three large shield volcanoes: the Rainbow Range, Ilgachuz Range, and Itcha Range.
The Anahim volcanic belt is one of a handful of obsidian sources in British Columbia used by indigenous people. Worked into knives and spear points, obsidian forms edges often sharper than is possible with modern-day surgical steel. Obsidian from this area has been traded and transported for millenia. The primary sources were at Bes But’a (Anahim Peak), Ilgachuz, and Tsitsutl.
The earliest known piece of Bes But’a obsidian – dated to about 9500 BP – was found at Namu, 160 km to the west. The implications are amazing. The Chilcotin has been part of a network of trails and inter-cultural contact since almost immediately after the retreat of the ice sheets. That’s approximately two thousand years before the most recent Nazko Cone eruption and a full ten millenia before the arrival of the first Europeans.
Resources:
C. Kuehn. A second north American hot-spot: Pleistocene volcanism in the anahim volcanic belt, west-central British Columbia. PhD thesis. University of Calgary. 2014.
https://prism.ucalgary.ca/handle/11023/1936
William J. Turkel. The archive of place: Unearthing the pasts of the Chilcotin plateau. 2007.