“The megaripples date back to the end of the Cretaceous period 66 million years ago, when part of the state was underwater,” the researchers were quoted as saying. Live Science, Thursday (22/7/2021).
The size and orientation of the megaripples suggest that they formed after the giant space rock, known as the asteroid Chicxulub, hit the Yucatán Peninsula, causing the Chicxulub impact tsunami. Then the tsunami waves flow into shallower waters and create megaripple marks on the ocean floor.
Study lead researcher Gary Kinsland, a professor in the School of Geosciences at the University of Louisiana at Lafayette, told Live Science said, this is just further evidence that the Chicxulub impact ended the Cretaceous period.
Kinsland has previously studied the Chicxulub collision crater. When he saw the seismic picture, “I immediately saw the ripples, and I immediately knew the direction the water was supposed to go,” he said.
This ancient ripple shows that after space rock hitting Earth 66 million years ago, a tsunami hit the Gulf of Mexico. Then the megaripples broke off the coast when it “reached the Gulf of Mexico shallow end in what is now central Louisiana,” the researchers wrote.
After the tsunami created the megaripples, they remained underwater. They are deep enough underwater that when a storm sweeps across the Gulf of Mexico, the megaripples remain undisturbed, Kinsland said.