Grand Canyon as old as the dinosaurs, study suggests

TORONTO – There’s lying about your age – and then there’s this.

New research suggests the Grand Canyon is more than 60 million years older than previously thought.

An analysis of the minerals at the bottom of the Grand Canyon indicates the natural wonder was largely carved out 70 million years ago, when dinosaurs roamed the Earth.

Scientists believe dinosaurs were wiped out around 65 million years ago, likely in the aftermath of an asteroid crashing into Mexico’s Yucatan Peninsula.

The study, led by a team from the University of Colorado Boulder, was published Thursday in Science magazine.

The researchers focused on the western end of the Grand Canyon occupied today by the Hualapai Reservation, which owns the Skywalk
attraction, a horseshoe-shaped glass bridge that extends from the canyon’s edge.

To come up with the age, the team crushed rocks collected from the bottom of the canyon to analyze a rare type of mineral called apatite. The mineral contains traces of radioactive elements that release helium during decay, allowing researchers to calculate the passage of time since the canyon eroded.

Their interpretation: The western Grand Canyon is 70 million years old and was likely shaped by an ancient river that coursed in the opposite direction of the west-flowing Colorado.

“An ancient Grand Canyon has important implications for understanding the evolution of landscapes, topography, hydrology and tectonics in the western U.S. and in mountain belts more generally,” said Rebecca Flowers, assistant professor at CU-Boulder.

The age of the Grand Canyon has been a topic of controversy amongst scientists.

Not everyone is convinced with the latest viewpoint published online Thursday. Critics contend the study ignores a mountain of
evidence pointing to a geologically young landscape and they have doubts about the technique used to date it.

The notion that the Grand Canyon existed during the dinosaur era is “ludicrous,” said geologist Karl Karlstrom of the University of New Mexico in Albuquerque.

There have been numerous studies over the past few years, which report various ages of the Grand Canyon. The most popular theory to date places its age at 5 million to 6 million years old. And a 2008 study published in Science magazine placed the age of the canyon at 17 million years.

Scientists have a variety of data on the Grand Canyon that suggest it has had a complicated history. The modern canyon we see today may not have been carved out all at the same time.

The debate surrounding the canyon’s age has spurred a resurgence in efforts from geologists to put the issue to bed.

“If it were simple, I think we would have solved the problem a long time ago,” said Flowers. “But the variety of conflicting information has caused scientists to argue about the age of the Grand Canyon for more than 150 years. I expect that our interpretation that the Grand Canyon formed some 70 million years ago is going to generate a fair amount of controversy, and I hope it will motivate more research to help solve this problem.”

Some 5 million tourists flock to Arizona each year to marvel at the 277-mile-long chasm, which plunges a mile deep in some places.

With files from Alicia Chang, The Associated Press