Massive icebergs may have heaved off and been pushed as far south as Florida during Ice Age floods. CC/NASA |
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CONWAY, S.C., Oct. 14 (UPI) -- The ocean floor off the coasts of South Carolina, Georgia and Florida is scarred, left furrowed and plowed with V-like trenches by colossal icebergs that once made their way southward during massive Arctic flooding, according to a study published this week in the journal Nature Geoscience.
Some 20,000 years ago, what's now Canada served host to giant lakes full of frigid fresh water. Ice dams kept the lakes' holdings at bay, separating lakes as big as the Caspian Sea -- like Lake Agassiz -- from the Atlantic Ocean. Occasionally, these ice dams collapsed, and walls of fresh water spilled into the ocean via the Gulf of St. Lawrence and Hudson Bay.
With each new Ice Age flood, the unleashed water carried along intimidating fleets of craggy icebergs. The V-shaped scours found along the North America's southeast coast are proof that these icebergs made the journey all the way from Canada to South Florida.
Finding evidence of icebergs so far south, researchers say, changes the way scientists understand ocean currents, the melting of the ice caps and global warming.
"The mechanisms of climate change and ocean currents are more complex than we previously thought," study author Jenna Hill, a marine scientist at Coastal Carolina University, said in a press release. "It helps us understand how future ice sheet melt from Greenland may affect global climate."
"Previous research would have suggested the meltwater would have gone much further north, so people weren't expecting the subtropics to become fresher," explained co-author Alan Condron, an oceanographer at the University of Massachusetts, Amherst. "This actually has enormous implications for that model and for what triggers climate change."
Condron says the scours suggest some of the southward-drifting icebergs were as thick as 1,000 feet; icebergs of that size today are found only off the coast of Greenland.
"This new research shows that much of the meltwater from the Greenland ice sheet may be redistributed by narrow coastal currents and circulate through subtropical regions prior to reaching the subpolar ocean," Condron added.
The work of Hill and Condron is detailed in the journal.
