Question

Canyon Formation
Read the passage and answer the following question(s).

Canyon Formation
Geoscience processes change the surface of Earth at various time and spatial scales. Some processes, such as the uplift of mountain ranges, occur over a long period of time. Others, such as volcanic eruption, occur over a short period of time. Processes can be small in scale like the weathering of a rock, or large in scale like the motion of Earth's plates.

In the formation of a canyon, moving water breaks down rock that is then transported away. The Colorado River has been forming the Grand Canyon in the United States for about 6 million years. The Grand Canyon now covers about 1,900 square miles. The picture shows how a canyon can form over millions of years.

From left to right, the picture shows (1) a river with water flowing even with Earth's surface, (2) the river has worn away some earth and the water is flowing at a lower level than Earth's surface, and (3) the river has worn away even more earth and the water is flowing at a level much lower than Earth's surface.

Resize Columns
Question 1.


Most rivers eventually flow into the ocean. As a river nears the ocean, its speed slows down, and smaller channels form. Sediment being carried by the moving water settles to the sides and bottom of the channels. The place where the sediment piles up is called a delta. The picture shows an example of a delta.



Describe two similarities between the formation of a delta and the formation of a canyon.

Answer 1

1) Both are caused by moving water. Rivers erode rock and soil to form canyons and carry sediment downstream to build deltas.

2) Both change Earth’s surface over time by moving sediment. In canyons the sediment is removed (erosion and transport); in deltas the sediment is deposited when the water slows, producing a new landform.