SYNCHRONOUS ICE-DAM COLLAPSES AND OUTBURST FLOODING FROM NORTHERN HEMISPHERE PROGLACIAL LAKES AT YOUNGER DRYAS ONSET (12.8 KA) IMPLIES COSMIC IMPACT TRIGGER
These records alone, demonstrate that both the huge North American and European proglacial lakes catastrophically drained into the surrounding oceans through ice dam failure at exactly the same time. Furthermore, significant evidence now exists for more widespread ice sheet margin and glacial lake instability at the YD onset. This includes the Greenland Ice Sheet that demonstrates noticeable instability of the ice sheet margin at or close to the YD onset. Also, evidence exists for the establishment of eastward drainage through the St. Laurence Seaway at the YD onset, including the final drainage of proglacial Lake Vermont and the initial incursion of marine conditions there that mark the Champlain Sea, as shown by T. Cronin and colleagues. Other effects of such plumbing changes in the sediment record are from the St. Laurence estuary, Labrador Sea and Hudson Strait.
It is difficult to explain the triggering of such widespread synchronous changes at the margins of three relatively isolated Northern Hemisphere ice sheets; Laurentide, Fennoscandian and Greenland, and their related proglacial lakes by invoking conventional climatic and/or paleoceanographic processes. Instead, this broad range of evidence is more readily explained by catastrophic processes triggered by a cosmic impact with Earth; the YDB cosmic impact theory.