A surprising new study finds that the Grand Canyon landslide-dam has more in common with the Meteor Crater impact than you might think. Together, these two geologic wonders define the American Southwest. This work was led by University of New Mexico Distinguished Professors Emeritus Karl Karlstrom and Laurie Crossey. Their work appeared in the journal Geology.
Meteor Crater, just east of Winslow, Arizona, was created by a spectacular impact about 56,000 years ago. This event is now thought to have caused a landslide dam at the Grand Canyon. It dammed up the Colorado River and as a result, created an enormous paleolake. Her impact formed a shockingly beautiful magnitude 5.4 earthquake. Some estimates even indicate it could have reached a catastrophic magnitude of 6 under certain conditions.
The Meteor Crater impact generated a far-field shock in which the maximum amplitude reached only a ~3.5. It zoomed the 100 miles distance to the Grand Canyon in mere seconds. This rapid downstream transmission of energy probably helped to facilitate the geological changes that are seen in the Grand Canyon.
Evidence indicates that the landslide-dam at the Grand Canyon was likely overtopped and significantly eroded within less than 1,000 years following the impact. The region has experienced the most severe historic biodiversity loss of any U.S. region. Even more alarmingly, species such the California condor and Harrington’s mountain goat have become extinct. Perhaps most importantly, researchers have dated driftwood found in the Grand Canyon to over 35,000 years old. Recalibrations in 1984 showed an even older age of 43,500 years.
To achieve this, researchers utilized cutting-edge dating techniques and analysis from two labs in New Zealand and Australia. In 1975 they dated the Meteor Crater impact at a then impressive, geologically speaking, age of 56,000 years. These results indicated that the mean dates obtained through various methods tended to cluster tightly around each other. Nonetheless, these diverged into a surprisingly tight time frame of 55,600 ± 1,300 years ago. This convergence suggests a causal relationship between the Meteor Crater impact and the subsequent geological events at the Grand Canyon.
This study is not just about geological curiosity. Even more importantly, it gives us better insight into how catastrophic events like floods and wildfires reshape landscapes and ecosystems over time. The connection between these two iconic landmarks offers insights into the Earth’s geological history and the dynamic processes that continue to shape its surface.
