That's really old: Testing done in caves along the Grand Canyon has led to an increasing of the believed age of the western section of the canyon, pegging it at around 17 million years old.
Courtesy RealbrvhrtRegular readers of the Buzz may have noticed that there are some subjects I just can’t let slide by without comment, primarily anything having to do with Vikings, smoking, steroids and my all-time favorite topic, the Grand Canyon.

And news broke today that the Grand Canyon has been pulling one over on us when it came to its age. While no amount of Botox can even begin to cover up all its wrinkles and creases, we just might have been grossly underestimating its age all these years.

The commonly accepted age for the canyon has been set at around 6 million years, primarily based on geological clues in the rocks that form the canyon’s walls.

But researchers poking around in some of the canyon’s caves now figure that the carving of the western section of the canyon might have started as far back as 17 million years ago. Also, these same researchers think that the Grand Canyon may be the ultimate combination of two canyons that cut through northern Arizona at different times, with the eastern section of the canyon being “newer.”

The first thing you have to kick out of your head when comprehending all this is that the Colorado River – which currently snakes its way along the canyon’s base – was not the original river or water drainage system to carve out the canyon. So we can’t lock our thinking into that being a major factor in the canyon’s creation.

One of the big challenges in using geology to date a canyon is that erosion and canyon carving has continued on. So the clues we can find on the canyon’s surface or walls have themselves become compromised by the elements.

That’s why researchers from the University of New Mexico went into caves along the canyon to gather more geological clues. Those clues haven’t been altered by water run-off, wind or other eroding agents.

Rock samples were taken from ten different caves along the length of the canyon. And through the use of uranium-lead isotope testing, the section of the west canyon came out to being dated as 17 million years old.

Those tests also showed that the west canyon’s formation worked both east and west. It was a long, gradual process, with the canyon being cut at a rate of about two inches per 1,000 years.

That eastern, backward erosion eventually hooked up with the eastern canyon formation action about 5 or 6 million years ago to make one huge canyon. And with the bigger canyon, the carving pace accelerated to a rate of 8 to 12 inches each 1,000 years.

Mixed into all of that were geologic forces from under the earth that were pushing rock formations in the area up at the same time erosion forces were cutting down. And that, my friends, is how you get one impressive canyon.

Also, right now the Grand Canyon is in the midst of a three-day water release at the Glen Canyon Dam that is designed to redistribute sediment in the canyon and simulate the occasional spring floods the canyon received before the Colorado River was dammed. That process has occurred several times in the past and has controversies of its own to talk about.

Here are links to couple of the other Grand Canyon related Buzz content I’ve recently posted:

• Lake Meade dropping
• Grand Canyon Skywalk to open

Feel free to share your Grand Canyon thoughts here with other Science Buzz readers.

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