Viewing posts tagged lava column hikes

Devil's Postpile National Monument, California

Our day started early for a hike in Devil's Postpile National Monument. We had breakfast in the park and began our hike. The hike to the postpiles was short about 1 mile roundtrip. The postpiles look like tall tree trunks stacked high and upright against each other, measuring 40-60 feet (12 to 18 meters) high.  These Postpiles were formed as a product of the slow cooling of a hot basalt lava lake. The lava lake was 400 feet deep and existed between 80,000 to 100,000 years ago. As the lava lake cooled, cracks (called joints by geologists) formed to release the tension that lay within. Cracks extended from the outside in, forming these hexagonal columns. These hexagonal columns were later exposed by many forces, one of them being glacial excavation. You can see the glacial striations on the rock at the top of the columns on the hexagonal “tiles”. Though very much man-made in appearance, these hexagonal shapes are common in nature - example bee hive honeycomb, packed bubbles, eyes of flies.  For more information on the geology of these postpiles, see Geology of Devil's Postpile