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Related: About this forumGrand Canyon is not so ancient
Grand Canyon is not so ancient
Parts of famous chasm are tens of millions of years old, but integration happened more recently.
Alexandra Witze
26 January 2014
A longstanding geological fight over the age of one of the most iconic landscapes in the United States Arizona's Grand Canyon may finally be over. The massive chasm does not date back 70 million years, as earlier work had suggested, but was born in its entirety 5‒6 million years ago when older, shorter canyons linked together to form the complete structure.
This explanation aims to reconcile a flurry of seemingly contradictory findings that enlivened discussion about when the canyon was carved.
I think weve resolved the 140-year-long debate about the age of the Grand Canyon, says Karl Karlstrom, a geologist at the University of New Mexico in Albuquerque. He and his colleagues describe the findings today in Nature Geoscience.
Geologists agree that the colorful layers of rock that make up the canyon walls are ancient, dating back as much as 1.8 billion years. The debate focuses on a different number when exactly the Colorado River began cutting through those layered rocks, forming the three-dimensional chasm that tourists swarm to today.
More:
http://www.nature.com/news/grand-canyon-is-not-so-ancient-1.14584
knitter4democracy
(14,350 posts)nt
Warpy
(111,351 posts)and just as fun to get to---miles and miles of flat valley land until you come to a bridge and it all falls away. The area is green, unlike the Grand Canyon. It's worth the half hour drive out and back if you ever do the tourist thing in Taos.
Still, the age of the Grand Canyon (and probably the Rio Grande Gorge) shows just how fast the western half of the country got jacked up as the Juan de Fuca plate slid under it. The rivers are where they've always been. The land they once ran over just kept getting higher every year.