Book 5, Question 62
Deep Cuts! Why Do Canyons Get Deeper?
Water flowing through a canyon slowly wears away rock and carries bits of it downstream. Over a very long time, the river cuts deeper and deeper. Wind and weather help wear the sides too.
From the book
Page from A Million Whys Book 5
More fun facts
- Canyons are deep, narrow valleys cut by erosion.
- When a river carves down into the rock, it is called downcutting.
- The rocks deep in the Grand Canyon formed almost two billion years ago.
- Between 70 and 30 million years ago, the whole region was pushed up high, which gave the river more drop to cut with.
- The Colorado River started carving the Grand Canyon only about 5 to 6 million years ago.
- Water flowing in from side streams has made the canyon wider.
- Inside the Grand Canyon, the Colorado River averages about 300 feet across and about 40 feet deep.
Sources: National Park Service, National Geographic
Questions kids ask
Why is the Grand Canyon striped?
Its walls are made of layer upon layer of rock, each one formed at a different time.