Limestones on Sacajewea Peak were metamorphosed into marble by the heat of adjacent granitic intrusions.
Basalt dikes in the Wallowa Mountains
Individual Columbia River basalt dikes, exposed by uplift and glaciation, extend for many miles.
Rhyolite columnar jointing
Rhyolite flows like these in Ashwood, Oregon, may form large, blocky columnar joints.
A hand lens is helpful in identifying minerals, even in the field.
Tropical soils, developed in volcanic ash deposits produce red, lateritic soils.
Lahars, or volcanic debris flow, Clarno Formation, John Day Fossil Beds National Monument, Oregon.