June Geology Image of the Month: Columnar Dacite in Mount Rainier National Park

June’s geology image of the month was taken by State Geologist Dave Norman. The dacite columns, located on the northeastern flank of Mount Rainier along Sunrise Road, are part of the Burroughs Mountain flow. They were formed as lava that erupted from Rainier traveled along the periphery of the glacier that once filled White River Valley. Unable to melt through the thickest glacial ice, the lava formed ridges at the glacier margins. To discover more about the fascinating geology of Mount Rainier and plan your own field trip, download our comprehensive pictorial guide: Roadside Geology Of Mount Rainier National Park And Vicinity.