The Strawberry Volcanics cover an area of 975 square miles (2,500 square km) in north-eastern Oregon. Two vents produced most of the volcanics which consist of basalt to andesite lava flows and lesser volumes of dacite and rhyolite. Most of the lava was erupted between 15-20 million years ago. Volcanism continued to about 10 million years ago. This photo shows an excellent exposure of lava flows of the Strawberry Volcanics at Strawberry Mountain, 17 miles (27 km) southeast of John Day, Oregon. Photo courtesy of the Oregon Department of Geology and Mineral Industries. Special thanks to Rosemary Kenney.
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