Evidence of a two-fold glacial advance during the Last Glacial Maximum in the Tagliamento end moraine system (SE Alps).

The glacial history of the Tagliamento morainic amphitheater (southeastern Alpine foreland, Italy) during the last glacial maximum (LGM)has been reconstructed by means of a geological survey and drillings, radiocarbon dating and pollen analysis in the amphitheater and in thesandur. Two phases of glacial culmination, separated by a distinct recession, are responsible for glacial landforms and related sediments in theouter part of the amphitheater. The age of the younger advance fits the chronology of the culmination of the last glaciation in the Alps, wellestablished between 24 and 21 cal ka BP (20 to 17.5 14C ka BP), whereas the first pulse between 26.5 and 23 cal ka BP (22 to 21 14C ka BP),previously undated, was usually related to older (pre-LGM) glaciations by previous authors. Here, the first pulse is the most extensive LGMculmination, but is often buried by the subsequent pulse. The onset and final recession of the late Würm Alpine glaciation in the Tagliamentoamphitheater are synchronous with the established global glacial maximum between 30 and 19 cal ka BP. The two-fold LGM glacial oscillationis interpreted as a millennial-scale modulation within the late Würm glaciation, caused by oscillations in inputs of southerly atmosphericairflows related to Dansgaard-Oeschger cycles. Phases of enhanced southerly circulation promoted increased rainfall and ice accumulation inthe southern Alps.