With the help from the National Science Foundation, the University of North Carolina at Wilmington, and others, the researchers reviewed a millennium approximately 120,000 years ago when temperatures were slightly warmer than today, Earth’s glaciers had melted, and the world’s sea levels were almost 30 feet higher. The scope of the period of the study ruled out tsunamis, said Hearty.
The researchers concluded big waves and wind pushed boulders, rocks, sediment, and other materials from the ocean almost six miles inland on the islands in what were probably epically violent storms.
They looked at boulders as heavy as 1,000 tons that were once underwater but now sit on land that was dry before they arrived, so-called “chevron storm ridges,” or V-spaced lines of sediment pushed inland by rushing water and deposits of beach sedimentation almost 100 feet above sea level.
“Super perfect storms,” said Hearty.