At Artist Point, the Grand Canyon of the Yellowstone reveals its spectacular natural painting of pastel-colored canyon walls and the impressive Lower Falls.
The Yellowstone River originates in the Absaroka Range in southeastern Yellowstone, flows through Yellowstone Lake, and then drains northward through the 20-mile (32 km) long Grand Canyon of the Yellowstone. The steep walls of this narrow canyon are carved into relatively soft rhyolitic lava and tuff, which have been chemically altered by hot groundwater. Numerous hot springs in the canyon area continue to alter the color of the originally dark-gray rhyolite into the famous yellow, brown, and red hues that gave Yellowstone its name.
At Lower Falls, an average of 37,400 gallons (141,800 l) of water plunge 308 feet (93 m) into the canyon every second, cascading over an unaltered edge of resistant gray rhyolitic lava. The explosive history of this supervolcano has repeatedly changed the appearance of the canyon during the last 484,000 years through alternating phases of volcanic ash and debris filling the canyon and subsequent incision by the flowing river.
During the ice ages, the drainage system was repeatedly blocked by ice caps, creating a long lake within the canyon. About 12,000 years ago, the ice melted away, and the Yellowstone River resumed its erosive work. It gradually deepened the canyon into its present V-shaped form, removing even the glacial sediments that had accumulated within it.
The evening sun casts an enchanting light on the pastel-colored volcanic rocks of the Grand Canyon of the Yellowstone and the Lower Falls.
