A new oceanographic study shows that there was likely a time when icebergs floated past the coast of modern-day Florida and into the Caribbean Sea.

“Our study is the first to show that when the large ice sheet over North America known as the Laurentide ice sheet began to melt, icebergs calved into the sea around Hudson Bay and would have periodically drifted along the east coast of the United States as far south as Miami and the Bahamas in the Caribbean, a distance of more than 3,100 miles, about 5,000 kilometers,” said Alan Condron of the University of Massachusetts Amherst.

According to Condron, these results would imply that abrupt climate change mechanisms are much more complex than was thought. His research with Jenna Hill of Coastal Carolina University has been published in the journal Nature Geosciences.

A series of high-resolution sea-floor images, analyzed by Hill, revealed 400 scour marks from Cape Hatteras to Florida, which were made when massive icebergs floated into shallower water and banged against the seabed. “The depth of the scours tells us that icebergs drifting to southern Florida were at least 1,000 feet, or 300 meters thick,” said Condron. “This is enormous. Such icebergs are only found off the coast of Greenland today.”

“In order for icebergs to drift to Florida, our glacial ocean circulation model tells us that enormous volumes of meltwater, similar to a catastrophic glacial lake outburst flood, must have been discharging into the ocean from the Laurentide ice sheet, from either Hudson Bay or the Gulf of St. Lawrence,” says Condron.

This means that the icebergs would have floated past Florida for only a short time, perhaps a year or so, according to Condron. He and Hill believe that this research will add to on-going and future studies of abrupt climate mechanisms.