General Geology Map

The generalized geologic map of the Big Sky region depicts the geology of bedrock lying at or near the land surface, excluding the distribution of surficial materials such as soils, alluvium, and glacial deposits. Geology in the eastern portion of the partnership region is dominated by sedimentary rocks. Volcanic deposits occur around Yellowstone National Park, along the Cascade Mountains in western Oregon and Washington, and in the flood basalt provinces of Idaho, Washington, and Oregon. Numerous intrusive plutons and metamorphic complexes dominate northern Idaho and occur in western Montana and Wyoming.

Data Sources: US Geological Survey