Water and Rock: How the Grand Canyon Formed by Theresa Emminizer

Author:Theresa Emminizer [Emminizer, Theresa]
Language: eng
Format: epub
Publisher: The Rosen Publishing Group, Inc

SHIFTING UPWARD

The Kaibab Limestone is the topmost rock layer in the Grand Canyon. Based on radiometric dating, relative dating, and fossil identification, geologists have determined that this limestone likely was once an ocean floor. How exactly did the rock layer move from the ocean bottom to 9,000 feet (2,743.2 m) above sea level? The planet pushed it upward.

This geologic activity occurs in the lithosphere. This layer is made up of tectonic plates that float and move on top of a layer of soft rock. When the plates bump into each other, rocks on Earth’s surface shift.

Between 30 million and 70 million years ago, this activity changed the landscape of the Grand Canyon’s rock layers. The bumping plates pushed the rock layers upward, lifting the land and creating what’s called the Colorado Plateau.

CONTINENTAL DRIFT

The continents that we know today were all once part of a supercontinent called Pangaea. Pangaea was a huge landmass that broke apart into pieces over time. The movement of tectonic plates caused the continents to shift. If you look closely at a map of Earth, you can imagine how the continents once fit together. Earth’s plates continue to move today, crashing into and pulling away from each other. This movement is where many kinds of geologic activity begin.

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