The Crooked River Caldera

Jason McClaughry

Oregon Department of Geology and Mineral Industries

5:30 pm social hour

The Crooked River caldera is a 26-mile long, 17-mile wide volcanic depression formed through a series of super-volcanic eruptions between 29.7 and 27.5 million years ago. Eruptions from the Crooked River caldera deposited massive volumes (>140 cubic miles) of tuff and rhyolitic lavas, dikes, and domes. All of these volcanic features are now well exposed in the rock walls of Smith Rock State Park. Current research suggests that the Crooked River caldera records some of the oldest caldera-forming eruptions related to the passage of the Yellowstone volcanic hotspot from the coast of the Pacific Northwest to the modern Yellowstone caldera in Wyoming during the past 50 million years. Jason’s talk will focus on regional tectonic models and geochemistry linking the Crooked River caldera to the Yellowstone volcanic hotspot.