Uncovering the 52-Foot ‘Megaripples’: 3D Mapping of Asteroid Impact Sites Beneath Louisiana That Helped Shape Dinosaur Extinction

New research reveals that the “megaripples” created by the tsunami from the Chicxulub asteroid impact stretch much wider than scientists previously realized. This study sheds light on the immense forces unleashed 66 million years ago, when the asteroid struck Earth and caused mass extinction.

Published in the journal Marine Geology, researchers analyzed petroleum industry 3D seismic data. They discovered that these tsunami-driven megaripples cover a vast area, expanding our understanding of the tsunami’s effects.

In an earlier 2021 study, Gary Kinsland from the University of Louisiana at Lafayette and his team first identified a 77-square-mile region of these ripples on what is now Louisiana’s continental shelf. This area used to be underwater and extended from the coast into deeper waters.

The researchers had noted that these megaripples, averaging 52 feet high and 1,970 feet wide, were shaped by the tsunami that surged across the ocean floor after the impact. Building on that work, this new study looked at 900 square miles of 3D seismic data, revealing that these ripples are widespread across the study area.

“The megaripples vary depending on their location,” Kinsland explained. “This information is vital for modeling tsunami behavior and predicting how future tsunamis might interact with coastlines.”

Near the continental shelf’s edge, for example, the ripples are more asymmetric due to the tsunami’s force on the shelf. This asymmetry helps researchers determine the tsunami’s direction, pointing back to the Chicxulub impact site in Mexico’s Yucatán Peninsula. Further inland, the ripples show different patterns, indicating how the tsunami behaved in shallower areas.

The researchers suggest these megaripples weren’t formed like typical beach ripples, which develop from individual sand grains. Instead, the massive shockwave from the impact likely fluidized sediment, allowing the waves to shape it into standing forms. Kinsland likens this process to making whipped cream, where the motion creates lasting ripples.

Understanding these ancient tsunami dynamics helps researchers prepare for the future. With modern asteroid-tracking programs, scientists can predict potential impacts and assess the global effects of such events. As studies continue, more will be learned about one of Earth’s most catastrophic moments, an event that transformed our planet’s landscape and life.