Mount Washington & Belknap Volcano, Oregon

Mount Washington (7,796 feet, 2,376 meters - northern peak) and Belknap Shield Volcano (6,874 feet, 2,095 meters - lower-left peak) are two distinctly different types of volcanoes located adjacent to each other. Belknap is a basaltic shield volcano, the first eruptive phase 2,900 years ago distributed basaltic cinders and ash over a broad area to the northeast and southeast. A second phase, 2,900 years ago, produced an adventive shield of basaltic andesite on the east flank, known as "Little Belknap". Mount Washington eruptions of uniform basaltic andesite produced an older shield volcano with a summit cone that reached an elevation of about 8,500 feet (2,600 meters). The summit consists of a micronorite plug, 1,300 feet (400 meters) in diameter. The age of Mount Washington is probably no more than a few 100,000 years, similar to that of other central High Cascade stratovolcanoes.