Visitors to Arizona can witness not just one but two extraordinary geological landmarks — the Grand Canyon and the Meteor Crater. Now, researchers writing in Geology believe the two attractions may be intertwined, sharing a history that goes back tens of thousands of years.
The paper follows recalculations of the Meteor Crater’s age, which suggest it was formed around 53,000 to 63,000 years ago when a meteorite plummeted to Earth and created a deep pit in the Arizona landscape.
Meanwhile, driftwood samples found in caves in the Grand Canyon have been dated, and recent analysis puts their age at around 56,000 years, leading researchers to speculate that the meteorite’s collision may have triggered a landslide large enough to block the Colorado River and create a paleolake in the Grand Canyon.
"Nevertheless, the meteorite impact, the massive landslide, the lake deposits, and the driftwood high above river level are all rare and unusual occurrences. The mean of dates from them converge into a narrow window of time at 55,600 ± 1,300 years ago, which gives credence to the hypothesis that they were causally related,” Karl Karlstrom, a professor in the Department of Earth and Planetary Sciences at the University of New Mexico, said in a press release.
Read More: Ancient Artifacts Have Been Found in the Grand Canyon, Going Back 12,000 Years
Ancient Driftwood and the Meteor Crater
The authors of the study trace its origins to the 1960s when Kalstrom’s father, Thor, was part of a team conducting research in the Grand Canyon’s caves. Archaeologists found split twig figurines made by local tribes 3,000 years to 4,000 years ago. Radiocarbon dating methods were used to determine the age of the material used to craft these figurines, with results at the time suggesting the driftwood was more than 35,000 years old.
Since then, technology has improved, and more recent estimates place the age of the driftwood around the 56,000 mark. This coincides with recalculations of the Meteor Crater, which experts believe occurred sometime between 53,000 years and 63,000 years ago.
Paleolake in the Grand Canyon
This new evidence led Karlstrom and his fellow researchers to reconsider an old hypothesis based on ancient driftwood discovered in Stanton’s Cave and put forward by Richard Hereford, a former scientist working at the U.S. Geological Survey (USGS), in the 1980s. Hereford had suggested a landslide near the Nankoweap Canyon could have caused a dam that, in turn, caused a paleolake to form in the Grand Canyon. The buildup of water would have enabled driftwood to float into Stanton’s caves — a cave that is, today, 44 meters (about 144 feet) above river level.
The addition of similarly aged material collected at comparable elevation levels from several other caves appears to provide additional evidence for Hereford’s case. Located at sites up to 940 meters (3,083 feet) above ground level, ancient driftwood suggests that water levels may have been historically much higher than they are today.
So, could the lake have been triggered by the meteorite’s impact? A magnitude 5.4 to 6 earthquake could have released powerful shockwaves that reached the Grand Canyon 100 miles away, loosening cliffs that were “waiting and ready to go,” the study’s authors say. This could have dammed the Colorado River, causing a paleolake to form.
“It would have required a 10-times-bigger flood level than any flood that has happened in the past several thousand years,” said Karlstrom.
More Research Is Needed
The presence of lake sediments 60 meters (about 200 feet) above the Colorado River — again dated to a period approximately 56,000 years ago — and the existence of beaver tracks high up in Vasey’s Paradise caves at elevations that would be inaccessible to beavers today provide additional evidence for this hypothesis. Still, more research needs to be conducted to conclusively determine whether this is indeed the case.
“The team put together these arguments without claiming we have final proof; there are other possibilities, such as a random rockfall or local earthquake within a thousand years of the Meteor Crater impact that could have happened independently," said Karlstrom.
Read More: Prehistoric Rock Art Lies Hidden Throughout the Grand Canyon
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Rosie McCall is a freelance writer living in London. She has covered science and health topics for publications, including IFLScience, Newsweek, and Health.
