On a beautiful sunny October day, we entered the most fantastic display of the erosional power of water … the Grand Canyon. The air was pleasant; soft clouds floated across the sky. Some of us closed our eyes as we approached the canyon, wanting to take in the view all at once.
Stretching before us was miles and miles of rock. Big, beautiful, old rocks. For most of us, this was our first time laying eyes on a geologic mystery. How did the Grand Canyon really come to be?
Many of us grew up believing that the Grand Canyon was incised by the Colorado River just about 6 million years ago, but this is still a conversation within the geological community. The Colorado River is a powerful river. It carries 500,000 TONS of sediment to the ocean every day and drops 10 feet per mile.
One hypothesis argues that the canyon was formed 70 million years ago by paleorivers and that the Colorado River did not play a major role in the formation of the canyon. Another hypothesis postulates that the the Grand Canyon was formed by linking canyons of varying ages together. Based on thermochronological data, the oldest section formed 70 million years ago, and the youngest sections were formed by the Colorado River 6 million years ago.
The Grand Canyon is nothing short of incredible. All of the water in all of the world’s rivers would only fill the canyon halfway. The oldest rock formation in the canyon, the Vishnu Schist, is over 1 billion years old. Looking at the canyon is like looking back in time, because the rock walls reveal millions of years of history.
P.S. We saw an elk!