The majestic Grand Canyon was carved from the rocks in Northeastern Arizona. Scientists are learning more about this area and have found it may be even older than they thought! Read this lesson to find out more about this giant formation.
Welcome to the Grand Canyon!
A canyon is basically a gigantic valley or gorge in the Earth's surface. That may not sound too exciting, but the 277-mile long Grand Canyon stuns millions of visitors every year with its beauty and sheer size.
This natural wonder, located in Northeastern Arizona, is one of the most famous natural formations in the world, and it's easy to see why. You can stand at the rim and admire the colorful layers of rock descending to the Colorado River, which is at the bottom. You can also travel down to the river itself and raft along its thrilling rapids. Scientists study the river and rocks to piece together the Grand Canyon's history. How was it formed? Although there are many questions to answer, scientists have outlined some of the major evidence.
Over a billion years ago, what is now the Grand Canyon was underwater. It was covered by an ancient ocean that was home to numerous prehistoric animals. Tiny pieces of rocks and soil called sediment were deposited in layers, along with volcanic rocks. As the Earth's surface moved and shifted, these rock layers were pushed up, forming mountains. Once these rocks were exposed to the elements, they were subject to erosion, which is a gradual wearing away over time.
The Power of Water
Scientists agree that water is the main cause of erosion in the Grand Canyon. If you visit the canyon today, you will see a long, narrow river at the bottom of the steep walls. This is the Colorado River, and its movement has slowly carved away the rock layers over millions of years. The area does not get a lot of rainfall, and doesn't have much loose soil, so the river valley didn't spread out. That's why the canyon walls are so steep, and why the river valley appears so narrow.
How Long Did It Take?
Scientists study the rock layers of the Grand Canyon to determine their age and to figure out when the Colorado River carved through them. Most agree that the Grand Canyon probably formed between five million and six million years ago. However, recent findings suggest that the canyon's origins might go back way farther than that.
Some scientists think that an ancient river carved most of the Grand Canyon before the Colorado River even existed. Two older canyons, one as old as 70 million years, may have become part of the modern-day Grand Canyon. Not all scientists agree with this, but that's okay. Questioning and discovery are what make science so cool!
The Grand Canyon is a large, deep river valley in Northeastern Arizona. The main cause of the erosion that formed the Grand Canyon was water; most scientists agree that it formed when the Colorado River started carving through layers of volcanic rock and sediment between five million and six million years ago. New evidence suggests that the canyon might be as old as 70 million years, though not all scientists agree.