Kingman Road Cut

October 12, 2005

Peachspringstuff copy

Provided by: Kay Meyer
Summary authors & editors: Kay Meyer

Just outside Kingman, Arizona, a road cut on I-40 reveals spectacular layering, which is both beautiful and a reminder of Earth’s violent past. About 18.5 million years ago, a powerful eruption occurred, lifting 72 cubic miles of volcanic ash into the air. This ash settled out and was eventually compressed into the Peach Springs Tuff. The tuff covers parts of Arizona, Nevada, and California, and is exposed in various places from Barstow, California to Peach Springs, Arizona. This cream colored, light brown, and salmon pink horizontal tuff is topped by dark brown vertical columns of rhyolitic welded tuff, which formed as partially melted airborne ash and rock particles fused when they fell back to the surface. Note also the fracture lines running vertically through the tuff and the upward displacements.

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