Icebergs May Have Vacationed in Miami During the Last Ice Age
According to oceanographer Alan Condron.
New numerical modeling examined ocean circulation during the last ice age, about 21, 000 years ago, indicates that icebergs from the North American ice sheet may have frequently made it to South Carolina and sometimes even as far south as south Florida. These models are consistent with recently discovered iceberg scour marks on the ocean floor.
High-resolution images of the sea floor between Cape Hatteras to Florida identified roughly 400 markings formed by huge icebergs, as thick as 1,000 meters. Icebergs of this size are only today seen in the northern latitudes off the coast of Greenland.
By simulating the release of glacial meltwater floods in a numerical ocean circulation model, Condron determined that large volumes of meltwater would have had to slough off the Laurentide ice sheet from the Hudson bay or Gulf of St. Lawrence. This would have temporarily reversed the direction of the Gulf Stream as cold water from the north flowed south. Water off the coast of Florida would have therefore been near-freezing as icebergs appeared as far south as the Florida Keys.
A description of Condron’s work in conjunction with Jenna Hill of Coastal Carolina University can be found in the advance online issue of Nature Geosciences, if you are fancy enough to have a subscription.
According Condron and Hill, this data indicates that mechanisms of abrupt climate change are more complicated than ever realized; future research will have to examine coastal boundary currents and their relationship with ice sheet runoff and subpolar fresh water.
Source: EurekAlert Release
Image by Tech. Sgt. Dan Rea, U.S. Air Force [Public domain], via Wikimedia Commons