Scientists found evidence that the beautiful landscape from the Zion Canyon was created by an enormous landslide more than 4800 years ago.
A study published on Thursday describes the formation of the park as being very violent. A wall from Navajo Sandstone collapsed, sending rocks throughout the canyon at very high speed.
The landslide blocked the canyon on a distance of two miles, creating a lake. The formation was called Sentinel Lake and lasted for as long as 700 years before it dissipated.
The presence of a former lake is now evidenced by fossil mollusks and clay beds. Scientists used these fossils and fragments of soil to determine the ancient creation of the canyon and to determine its age.
In this particular study, geologists took samples from the rock deposit created after the avalanche. They tested the surface and found that the 12 boulders were deposited simultaneously. This finding was the first proof of the fact that the creation of the deposit was due to a single, enormous event.
“The ancient Zion landslide would cover New York City’s Central Park with 275 feet of debris. And you would need 90 times the volume of concrete in Hoover Dam to recreate the mountainside that failed,” said Jeff Moore, leading author.
Scientists could not find yet evidence for the cause of the event that created the canyon. The landslide was described as a catastrophic event that created a beautiful view for tourists today. But at the same time, a cataclysm of this dimension would have excruciating effects if happened in today’s world.
Even now, rock deposits originating from the ancient landslide create on their smaller earth slides.
The latest event was in 1995 when a movement in the stone structure led to extensive damages to the main road in the canyon. Seven years earlier, a slide in the Middle Fork Taylor Creed created a canyon that lasted three years, and the debris flow reached as far as to impact interstate vehicles.
Authors explain that these movements are part of a cycle. As the rivers dig into the bedrock, the walls of the canyon grow higher. The higher they get, the more difficult it is for them to sustain the load and they respond by landslides.
The Zion Canyon is still thought to be subject to further movements. Future rock avalanches are also probable. Scientists believe that the rocks deposited on the floor of the canyon will eventually get evicted and in time, the landscape will look completely different.
Image Source: Pixabay