DLESE description of Pacific Mountain System

This web page guides the user through the Pacific Mountain System geologic province, one of the most geologically young and tectonically active in North America. The generally rugged, mountainous landscape of this province, which includes parts of Washington, Oregon, and California, provides evidence of ongoing mountain-building. One map shows the plate tectonic setting of the Pacific Mountain System which straddles the boundaries between several of Earth's moving plates. This province includes the active volcanoes of the Cascade Range and the young, steep mountains of the Pacific Border and the Sierra Nevada. The user can find out more with links to USGS Cascades Volcano Observatory, Seattle region earthquake hazards, or North Cascades National Park geology. Links are provided to a simple shaded relief map and to several other shaded relief maps including ones with National Park locations and with major and subprovince boundaries. Image gallery links are given to several national parks sites: Lassen Volcanic National Park, Yosemite National Park, and North Cascades National Park.