How are canyon formed?

Answer 1

Canyons are formed by erosion caused by rivers. Cliffs on either side of a canyon are made of harder rock, but the area that has been worn away tends to be of a softer rock which is easily weathered by water, and also by wind.

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Not quite. There may be canyons formed along geological boundaries created by faulting, but the rock on one side is usually the same as that on the other.

Answer 2

Millions of years ago, sand and mud were deposited on the sea floor. When the ocean dried up, the sand and mud were left behind. As streams later flowed over the area, more layers of sand and mud were piled onto past layers of sand and mud. The pressure from layers upon layers of the sediment caused the bottom layers of sand and mud to be compressed into stone, with each layer a different color due to the various types of minerals.

As water from the rivers begin flowing through the rock, it seeps into the cracks and breaks large chunks of rock off the walls. The water carries away the sediment and larger, more defined courses forms through the rock. The deeper the canyon is, the faster the erosion process also is because the force of the water is channeled into a relatively small area. This explains why canyons are thinner at the bottom than at the top. Another reason as to why canyon walls are more eroded at the top is that wind and rain also contribute to the erosion. The walls at the top are exposed to these two forces for a longer period of time, so more of the rock at the top is carved away.

Canyons walls are seen as rock strata. Geologists can study these to determine geological events throughout history. Canyons walls have helped geologists determine periods of ice ages and other geological events, and they will continue to do so as more of the rock from the canyon walls fall off and expose fossils and other artifacts.

Answer 3

Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon.