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Keywords:Geology Rocks, Mountaineers, Pinnacle Peak, andesite, columns, glacial
Pinnacle_Peak_20210403_IMG_3010_iOS

Pinnacle_Peak_20210403_IMG_3010_iOS

Horizontal andesite columns on Pinnacle Peak trail, WA. Predate Mount Rainier (pre-eruption). Approximately 23-25 million years. Honeycomb, specific 4-6 sided and when solidifying/cooling lava flow contracts and naturally breaks, forming similar to mud cracks. Horizontal (vs. vertical) only happens when comes in contact with a glacier. These differ from the Columbia River "basalts."