In 1977, Jack Souther produced a synthesis of volcanism in the Canadian Cordillera and delineated several Neogene-to-Quaternary volcanic belts throughout British Columbia. One of these was the linear Anahim Volcanic Belt, which included the Wells Gray-Clearwater volcanic field at its eastern end. However, its origin had not yet been understood. In 1979, two volcano tectonic models had been proposed by Jack Souther, Mary Bevier and Richard Armstrong. This included a hotspot and a propagating crack controlled by stress fields related to large-scale plate tectonics of western North America.