The Grand Canyon was formed over 5 million years by the Colorado River carving through layered sedimentary rock. Erosion and weathering by the river and other natural forces caused the canyon to gradually deepen over millennia as the rock layers were exposed. Today, the 277 mile long canyon reveals nearly 40 distinct rock layers that range in age from over 2 billion years old at the bottom of the canyon to about 200 million years at the rim.

1. Grand Canyon 2018
By: Chloe Tippett

2. The Grand
Canyon is located
in Arizona. It is
277 miles long
and is 6000 feet
deep. It is
considered one of
the seven
wonders of the
world.

3. The Colorado
River runs
through the
Grand Canyon.

4. How was The Grand Canyon Formed?
Scientists believe that the Grand Canyon was carved by the Colorado River about
5 million years ago. The processes that caused this, and continue today, include
erosion and weathering.
Erosion: Erosion is the movement of rocks and soil from one place to another by water,
wind, and ice.
Weathering: Weathering is the break down of rocks and soil due to weather like rain,
wind, and temperature. An example of weathering is when a rock’s edges are rounded.
At the same time that the Colorado River was cutting down into the rock layers,
the rock layers themselves were rising up due to plate tectonics.
Plate Tectonics: The earth’s plates moved and collided.

5. Redwall Cavern (Mile 33.3)
This huge cavern is an example of erosion caused by water
hydraulics and wind.

6. Shear Wall (Mile 14.2)
These walls are an example of rocks that have
been weathered.

7. Rock Layers
The walls of the Grand Canyon expose nearly 40 different rock layers. These rock layers
formed at different times in the earth’s history. The layers at the top of the rim are about
200 million years old. The layers at the bottom near the river are over 2 billion years old.

8. What is Sedimentary Rock?
The different rock layers in the
Grand Canyon were formed by
mineral deposits that settled in
place for millions of years under
pressure, either under the earth’s
surface or under a prehistoric
ocean.
Types of sedimentary rocks
include:
● Limestone
● Sandstone
● Siltstone
● Shale
● Dolimite

9. Nankoweap Granaries (Mile 52.4)
Square windows, cut into the sandstone by
Puebloans about 1,000 years ago. They hauled their
grain (pumpkin seeds and corn) from the river delta
to these “storage units.” The granary kept the grain
dry during floods and protected it from animals.
This hike was a beautiful place to see rock layers.

10. Sandbars
Sandbars are important to the Grand Canyon’s
ecosystem. They provide habitat for native and
endangered fish, they support vegetation and help
protect archaeological sites. The flat ground also
provides great camping spots under the stars!

11. Little Colorado (Mile 61)
There are many side creeks to explore. The Little
Colorado is bright blue due to dissolved travertine
and limestone in the water. This is similar to
Havasu Creek, another major tributary.

12. Elves Chasm (Mile 117)
Elves chasm is a beautiful
waterfall with a small cave
above it and under it. This is
another example of
something that was formed
due to erosion and
weathering.

13. Lava at Lava Falls (Mile 180)
The Grand Canyon also has a history of volcanic activity. The
evidence of this is the hardened lava that spills down the
canyon walls all the way to the river.

14. Lava Falls (Mile 180) - Class 10 Rapid!

15. Flora and Fauna
Ring tailed cat
Cacti Big horned sheep