Yellowstone’s Obsidian Cliff: Humanity’s Tool Shed for the Last 11,500 Years
Written by Black Hot Fire Network on March 30, 2023
YELLOWSTONE NATIONAL PARK, Wyo. — Near the north entrance, an imposing mountain of black glass rises against the blue sky.
Spanning more than five square miles, the dark, sometimes translucent mass was formed from a rhyolitic lava flow that oozed out of the magma chamber of Yellowstone Caldera beneath the park, and cooled rapidly in the bitter cold of a glacial maximum, about 180,000 years ago.
