Grand Canyon is not so ancient

[Judi Lynn]

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 we’ve 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]

1. Canyon de Chelly's prettier. nt

nt

[Warpy]

4. So's the Rio Grande Gorge just outside of Taos

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.

[Downwinder]

2. Copper Canyon (Barranca del Cobre) is larger and deeper.

https://en.wikipedia.org/wiki/Copper_Canyon

[DreamGypsy]

3. Since we're playing the prettier, bigger game...Valles Marineris

Valles Marineris (Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter of 1971–72 which discovered it) is a system of canyons that runs along the Martian surface east of the Tharsis region. At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep,[1][2] the Valles Marineris rift system is one of the larger canyons of the Solar System, surpassed only by the rift valleys of Earth and (in length only) by Baltis Vallis on Venus.