Lake Agassiz final drainage event in the northwest North Atlantic

摘要

The 8.2 ka "climate'' event recorded in Greenland ice cores is subject of debates with respect to causal linkage with a collapse of the Atlantic Meridional Overturning due to the drainage of the late-glacial lake Agassiz. Here, we present records from the NW North Atlantic, down-current the flood discharge route, showing that the 9.5-8 ka interval was marked by a succession of events. The drainage itself corresponds to a twin-layer of carbonate-rich turbidites deposited within the calibrated 8.35-8.5 ka interval. Proxies of sea-surface and deep-current conditions do not indicate significant concomitant changes in the NW North Atlantic. The dataset,however, supports the concept that the 8.2 ka "climate'' event may represent one of the manifestations of climate instability during an interval with major changes of land drainage in NE America, due to the collapse of the Laurentide Ice Sheet, subsequent fast sea level rise and large scale reorganization of the North Atlantic thermohaline circulation pattern.