America’s Largest Crater Has Shock Link to Grand Canyon, Research Finds : ScienceAlert

Two of Arizona’s most well-known landmarks could also be linked by cosmic violence: the asteroid that gouged out Meteor Crater could have additionally prompted the formation of an historic lake within the Grand Canyon.

This stunning connection between Arizona’s world-renowned geological options stretches again 56,000 years, to when a 300,000 ton nickel-iron asteroid slammed into the Colorado Plateau with the drive of over 150 atomic bombs, creating the biggest meteor crater within the United States.

The resultant impact-generated earthquake could have prompted a rockslide within the Grand Canyon, damming the Colorado River and briefly making a physique of water 80 kilometers (50 miles) lengthy and greater than 100 meters (round 370 ft) deep in what’s at this time Nankoweap canyon.

Related: The Grand Canyon Is Missing a Billion Years’ Worth of Rocks. Scientists May Know Why

Meteor Crater (also referred to as Barringer Meteor Crater) is a comparatively younger and exceptionally well-preserved crater simply west of the town of Winslow, Arizona. The asteroid that produced it could have been solely 30 to 50 meters throughout, however the affect excavated 175 million metric tons of limestone and sandstone, forming a crater 1.2 kilometers throughout and about 180 meters deep. Today, such an affect would wipe out an city middle the size of Kansas City.

The newly launched study encompasses greater than 5 a long time of analysis, a global workforce of collaborators, and an evolution of scientific courting methods.

The proof for the Nankoweap paleolake hinges on driftwood and lake sediments present in Stanton’s Cave, which is located virtually 45 meters above the Colorado River. Carrying the driftwood as much as the cave “required a 10 times bigger flood level than any flood that has happened in the past several thousand years,” says Karl Karlstrom, a geologist on the University of New Mexico and co-lead writer of the research.

The Stanton Cave driftwood was initially collected in 1970 and radiocarbon dated within the Eighties, suggesting it was round 44,000 years previous – a determine that was on the restrict of radiocarbon testing at the moment. Additional driftwood samples have been later collected from one other excessive alcove, located 33 meters above the Colorado River and some kilometers downstream of Stanton’s Cave.

The two separate driftwood samples have been independently dated, utilizing totally different methods, at totally different labs. The researchers additionally analyzed the lake sediments utilizing luminescence courting, which measures the vitality of sunshine emitted by a sure materials.

This separate courting methodology, distinct from radiocarbon courting, offered “statistically indistinguishable” dates for the driftwood samples and sediments, converging to 55,600 years in the past.

Additionally, researchers discovered historic proof of a pure dam about 35 kilometers downstream of Stanton’s Cave. In locations, this historic dam materials is overlain with rounded river cobbles that have been deposited because the Colorado River overtopped the dam throughout a span of about 1,000 years.

Overall, the coinciding dates of the affect, landslide, driftwood, and lake sediments assist the concept that the Nankoweap paleolake was fashioned by a seismic occasion generated by an asteroid touring with a cosmic velocity of over 11 kilometers per second, producing a 10-15 megaton occasion upon affect.

The ensuing 5.4 magnitude earthquake traveled the 100 miles to the Grand Canyon in seconds, the place it hit with an efficient magnitude of three.5 and prompted a landslide that dammed the Colorado River and fashioned the Nankoweap paleolake.

The researchers do acknowledge the probabilities that the Nankoweap paleolake was the results of a pure landslide, or an unrelated earthquake.

“Nevertheless, the meteorite impact, the massive landslide, the lake deposits, and the driftwood high above river level are all rare and unusual occurrences” whose ages converge on a slim slice of time round 55,600 years in the past, concludes Karlstrom.

This analysis is printed within the journal Geology.