 Identifiable from the mid-Miocene period, it has recorded changes in the western-moving North American Plate because it is believed to have been relatively stationary for tens of millions of years. Since then it has formed a line of volcanoes called the Anahim Volcanic Belt, stretching from the coast to the Interior Plateau near Quesnel. Each of the volcanoes was once over the hotspot, but migration of the North American Plate has pulled the volcanoes away from the hotspot's magmatic source at a rate of 2 cm (0.8 in) to 3.3 cm (1.3 in) per year. As a result, the volcanoes are progressively older to the west. The composition of magma to the volcanoes and its supply change with time as the volcanoes grow over the hotspot and migrate away.
