A meteorite impact in northern Arizona may have caused a massive landslide in the Grand Canyon about 56,000 years ago, altering the course of the Colorado River and forming a now-vanished paleolake. Researchers found driftwood and lake sediments in Stanton’s Cave, which sits within Marble Canyon, joining a body of evidence that the river was once dammed by a rockfall. Radiocarbon dating places the wood before all known flood events and hints at a major geologic disruption likely caused by seismic shockwaves from the Meteor Crater impact over 100 miles away. The results were reported on July 15 in the journal Geology.

Meteor Impact May Have Formed Ancient Lake by Triggering Grand Canyon Landslide, Study Finds

As per a University of New Mexico report, the research team used radiocarbon dating and geological analysis to trace the driftwood’s origin to an ancient lake that formed after a powerful landslide blocked the Colorado River. The landslide may have been triggered by seismic waves from the Meteor Crater impact, which probably caused a magnitude 5.4–6 earthquake. Karl Karlstrom, one of the study’s co-lead authors, said such a flood would have been 10 times the size of any previously recorded in the last few thousand years.

The paper suggests that a dam created a 50-mile-long, 300-foot-deep paleolake with beavers’ tracks in caves above the river, indicating a significant geological event possibly related to Barringer Crater. But researchers acknowledge there may be other explanations, such as local earthquakes or rockfalls.

Deposit layers and so-called driftwood in cave systems more than 3,100 ft above sea level caused a lake to engulf a dam in the Grand Canyon, they say, with dramatic consequences for the region.

The meteor link to the landslide is “convincing”, experts mentioned, but it’s going to take more data to rule out all other possible triggers for the landslide and to figure out how a single event could reshape the Grand Canyon.