The famous Grand Canyon is one of the wonders of the world because of its enormous size and depth. It is a mile deep, 18 miles wide, and over 270 miles long. It’s easy to see why the Grand Canyon is the second-most visited national park in the nation, despite its remote location.
Like a huge gash in the landscape, canyons are deep gorges that currently have a river flowing through them or, at one time, had a river flowing through them. There are around 250 canyons around the world.
The Grand Canyon is in Northern Arizona, near the city of Williams outside of Flagstaff. Its rocks and how they were formed are some of the most well studied in the world. Over 5 million people per year visit the canyon.
How was the Grand Canyon formed? We’ll take a closer look now.
The Geology of the Grand Canyon
A collision between two layers of the earth’s crust almost 2 billion years ago began the Grand Canyon’s formation. This collision created the Colorado Plateau, where the Grand Canyon sits, with the highest rim of the Grand Canyon being over 7,000 feet above sea level. The collision billions of years ago between plates uplifted the ground of the plateau, which set the stage for a canyon to be cut deep into it.
The Vishnu Basement Rocks at the bottom of the Inner Gorge of the Grand Canyon are the oldest rocks found in the canyon. They’re 1.7 billion years old. These are worth noting because they are different from a majority of the more recent rocks in the canyon that were deposited over time. These original rocks were created during the plate merging that created the plateau.
Around 2 billion years of geological history can be seen on the walls of the Grand Canyon since the Colorado River created a cross-section of the rock layers through which it flowed. That’s why the canyon walls appear banded with different colors; different layers of rock that accumulated throughout time are now exposed.
Most of the rocks in the canyon are sedimentary from ancient water flows. This means that they are relatively soft rocks. The Colorado River was aided by these softer rocks when it created the Grand Canyon.
The Colorado River and the Formation of the Grand Canyon
The Colorado River began creating a channel through rock layers around 5 to 6 million years ago, though exactly when the canyon started to form is up for debate. The newly formed Rocky Mountains had created the Colorado River in response to precipitation run-off, and the Colorado River began flowing over ancient bedrock on the Colorado Plateau, which began carving its famous channel.
Where the river forms the canyon, the water from the river runs at a steeper slope than average. This helped the river carve a definitive channel over time through something as hard as a rock.
It’s not the water itself that carves away at the rock, though the water is essential for erosion to take place. The sediment in the water, such as sand, rubs against the rock as the water flows over it, causing it to slowly erode until a channel is formed. In essence, the Grand Canyon is just a large channel for the Colorado River.
Read about the age of the Grand Canyon.
Humans and the Grand Canyon
Artifacts up to 12,000 years old have been found near the canyon, along with cave drawings and pottery from early periods in human history. There is evidence that people have lived in the area since the last ice age.
Today, the Havasupai’s ancestral home is the Grand Canyon, as their ancestors have lived in the region for 800 years. Over 12 tribes claim the canyon as their home. Spanish colonizers found the canyon in the 1540s, and in 1919, the Grand Canyon became a national park.
During the process of establishing a national park at the Grand Canyon, the Havasupai people were excommunicated from their land and forced to live on a small reservation. Due to the efforts of popular media outlets, they were granted some of their ancestral lands back, which they currently control.
Spots like the Havasu falls require direct permission from the Havasupai people before they can be visited. Supai village is located at the bottom of the Grand Canyon and still receives its mail by mule.
Dams and the Grand Canyon
Because dams have contained flood levels well below their natural height, the surrounding sediment that the local ecosystem relies on has been negatively affected.
Since huge floods are now contained by human ingenuity, the deposition of sediment has dramatically decreased, which affects the ability for new plant growth. Flooding rivers are vital to the replenishment of ground soil around a river. If plants can’t grow, wildlife cannot sustain itself.
There have been controlled floods to correct the damage that has been inflicted on the canyon. The Colorado River has been extended beyond its capabilities through damming, and the ecosystem of the river has been negatively affected. There are hundreds of dams on Colorado’s tributaries, as well as about fifteen dams on the actual river itself.
Is the Grand Canyon the Largest Canyon in the World?
No, the Grand Canyon is not the largest in the world. The largest canyon in the world is the Yarlung Tsangpo Grand Canyon, which is over 17,500 feet deep and located in Tibet. This canyon is also about 30 miles longer than Arizona’s Grand Canyon.
Wildlife Native to the Grand Canyon
While the Grand Canyon appears desolate, there is a wide variety of wildlife that call the canyon home. There are around 450 types of birds in the park. 90 types of mammals, 48 types of reptiles, and ten species of amphibians also call the Grand Cayon home.
The most numerous critter type is invertebrates like insects, scorpions, and spiders. There are over 1,400 types of invertebrates in the Grand Canyon. There are only eight fish species that are originally from the Grand Canyon, with six of them being endemic.
Desert big-horned sheep historically and currently inhabit the canyon, but their populations have dwindled for a variety of reasons. Events like helicopters passing over disturb migration and feeding, which has an overall effect on the health of the herd.
The bird with the largest wingspan at 9.5 feet is the California condor. It has a historical home in the Grand Canyon. Due to human activity, populations declined, and efforts to reintroduce the California condor to the area have been successful.
The photo featured at the top of this post is © sumikophoto/Shutterstock.com
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