Yellowstone, Part 2: Grand Canyon of Yellowstone and Rock Formations
The incredible volcanic activity at Yellowstone has also contributed to the Grand Canyon of Yellowstone, a 24-mile long canyon that largely came about due to faulting of the rock when the Yellowstone Caldera eruption occurred approximately 600,000 years ago. It has since been deepened by erosion from the Yellowstone River, which continues to cut into the softened rock. The rock itself – a rhyolite – contains varying degrees of iron which was altered by the heat of the volcanic activity, leading to the oxidizing effect or rusted colors seen in the canyon today.
Other interesting geological features include the basalt columns seen in the North, Northwest parts of the park. Here the lava flow fractured into heaxagonal columns.