Interesting lava formation in Mount Rainier National Park

columnar dacite
A formation of columnar dacite in Mount Rainier National Park. Photo: Dave Norman/DNR.

Today’s photo of columnar dacite in Mount Rainier National Park has been the June Geology Image of the Month on DNR’s free e-newsletter, Washington State Geology News.

Captured by State Geologist Dave Norman, the image shows dacite columns on the northeastern flank of Mount Rainier along Sunrise Road. They are part of the Burroughs Mountain flow, formed as lava that erupted from Mount Rainier thousands of years ago 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 and hardened.

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.

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You can download a copy of the informative, 200-page, full color “Roadside Geology of Mount Rainier National Park and Vicinity” at no charge or purchase a printed copy from the state Department of Printing.

As the state’s geologic survey, DNR monitors, assesses, and researches causes of earthquakes, landslides, and volcanoes, and publishes information on geologic hazards – information critical to decision makers in government and the private sector, and key to reducing the human and financial effects of natural disasters.

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