Williams News Logo
Grand Canyon News Logo

Trusted local news leader for Williams AZ and the Grand Canyon

New study suggests Grand Canyon older than expected
Professors publish findings suggesting the Canyon is 70 million years old, previous estimate was 5 or 6 million

GRAND CANYON, Ariz. - New research suggests the Grand Canyon is 70 million years old, challenging the previous age estimate of 5 to 6 million years old.

Rebecca Flowers, an assistant professor at the University of Colorado Boulder, and Kenneth Farley, a professor at the California Institute of Technology, published their findings online Nov. 29 in Science magazine.

Rocks are hotter the further down they are in the earth and become cooler when erosion brings them closer to the surface.

In the study, researchers collected rock samples from the bottom of the Grand Canyon and analyzed them in the laboratory to date the cooling history of the minerals.

"So essentially, thermal history then allows us to decipher erosion and when the Grand Canyon was carved," Flowers said.

The new findings have a significance that extends beyond the Grand Canyon.

"This also has broader implications for western U.S. evolution," Flowers said. "Believing in a young canyon versus an old canyon suggests very different things for how the western U.S. has evolved in terms of its topography, its drainage systems and its landscape over the last 70 to 80 million years."

However, not all geologists agree with the 70-million-year-old age.

"The reason the results are controversial is that there is this prevailing view that the entire canyon was incised after 6 million years ago," Flowers said. "There is no evidence that demands that the entire canyon was carved after 6 million years ago."

Wayne Ranney, a geologist and author who has studied the Grand Canyon for 37 years, said geologists have proposed several theories about the Canyon's age throughout history.

John Wesley Powell, who explored the Colorado River and Grand Canyon in 1869, first suggested that the Grand Canyon was older.

"The idea of an old Grand Canyon is the minority view, but it is a view that has never gone away," Ranney said, adding that the Canyon can't be more than 80 million years old because at that time an ocean covered the area.

In 1934, Eliot Blackwelder proposed that the Colorado River was fairly young, and therefore the Canyon must be as well.

Then in the 1940s, Chester Longwell found evidence suggesting the Canyon could be no older than 6 million years.

Evidence supporting an older Canyon is found in deep side canyons on the Canyon's western edge. Geologists date gravel from these side canyons at 50 million to 60 million years old. Some geologists think the side canyons are part of the Grand Canyon and thus believe the Canyon must be similarly old.

Evidence supporting the idea of a younger Canyon comes from a gravel deposit on the western end of the Canyon called the Muddy Creek Formation. Geologists have estimated the gravel there to be as young as 6 million years old. Since the Colorado River runs through the deposit and it has no sediment from the Grand Canyon, geologists believe the formation predates the river and Canyon.

In Ranney's opinion, both groups are right.

"When you stand on the rim of the Grand Canyon today and look down into it, what you see is a feature that has been shaped in the very recent geologic past," he said.

However, Ranney said his descriptions of the Canyon's age always have an asterisk since he believes some features of the Canyon are older.

Finding a definitive answer is difficult because of the nature of the Grand Canyon.

"Because the Grand Canyon is this huge erosional feature in the landscape, it has removed most of the evidence of its earliest history," Ranney said. "As it gets older and older, the evidence for its earliest history gets less and less. There's really not enough evidence left to really say for sure how or when it formed."

Despite this challenge, Ranney believes the new findings will increase interest among geologists and the general public regarding the age of the canyon.

"It's too big of a place for one person to hold the entire answer to the Canyon," he said. "If we never figure out how it formed, it will never stop us from trying."


Donate Report a Typo Contact