207 A
The volcanoes of the towering Andes are the product of molten rock generated by the subduction of the Nazca plate beneath the South American continent (see Figure 2.11). Mountain systems, such as the Andes, which are produced in part by volcanic activity associated with the subduction of oceanic lithosphere, are called continental volcanic arcs. The Cascade Range in Washington, Oregon, and California is another mountain system that consists of several well-known volcanic mountains, including Mount Rainier, Mount Shasta, Mount St. Helens, and Mount Hood (Figure 2.17). This active volcanic arc also extends into Canada, where it includes Mount Garibaldi and Mount Silverthrone, among others.