Rapid fluctuations of the Laurentide Ice Sheet at the mouth of Hudson Strait: new evidence for ocean/ice sheet interactions as a control on the Younger Dryas

Ice-directional features and erratic lithologies of the last glaciation demonstrate that a major outlet glacier of the Laurentide Ice Sheet flowed NNE across outer Hudson Strait rather than SE down the Strait as previously hypothesized. Ice advanced more than 600 km from a Labradorean source, crossing Hudson Strait and outer Frobisher Bay, and advancing onto Hall Peninsula; the highest summits on Loks Land (circa 400 m asl), a large island at the SE tip of Hall Peninsula, were inundated by Labradorean ice. Three distinct Late Wisconsin advances have been recognized. The earliest, most extensive advance crossed Frobisher about 11.5 kyr B.P. and was maintained for circa 1 kyr. The maximum extent of the Labradorean advance coincides with the onset of Younger Dryas cooling. Based on a minimum cross-sectional area and reasonable estimates of ice velocity, the iceberg flux to the North Atlantic Ocean at this time was between 300 to 2400 km³ year^-1, about the same as the freshwater influx from the diversion of Lake Agassiz drainage to the St. Lawrence. We suggest that a combination of a massive iceberg flux and increased St. Lawrence discharge may have been required to initiate Younger Dryas cooling. -from Authors