Concept and global context of the glacial landforms from the Younger Dryas Stadial

The Younger Dryas (GS-1: ~12.9–11.7 ka) constituted a climate reversal, abruptly interrupting the rapid deglaciation prevailing in Termination I, and the previous consistent trend to warming that characterised the Bølling/Allerød interstadial. There is a general agreement on the causes of the abrupt cooling of the Younger Dryas: the arrival of large volumes of cold meltwater from Lake Agassiz and the Fennoscandian ice sheet to the North Atlantic, resulting in a weakening of the Atlantic Overturning Meridional Circulation (AMOC), although climate models suggest that other factors also need to be considered. As a consequence, the transfer of heat from subtropical regions of the Atlantic Ocean to the coastal areas of Europe was interrupted, causing an estimated temperature drop of 8ºC–9ºC in the vicinity of the Arctic Circle, attenuated towards southern latitudes. Both the Fennoscandian ice sheet and the glaciers of the European mountains underwent a halt in their general retreat, followed by a limited expansion leading to the formation of voluminous moraines.