Obsidian Cliff, YNP.

Obsidian Cliff, Yellowstone National Park....

Detailed Description

Obsidian Cliff exposes the interior of a thick rhyolite lava flow erupted about 180,000 years ago. The vertical columns are cooling fractures that formed as the thick lava flow cooled and crystallized. The flow consists of obsidian, a dark volcanic glass.


Image Dimensions: 800 x 500

Date Taken: