Four boulder samples from the Piano del Praiet frontal moraine in the Gesso della Barra Valley (Maritime Alps) have been 10Be dated. The results give a weighted mean age of 11 340370 (870) yr, constraining the frontal moraine to the Egesen glacial stadial, during the Younger Dryas cold phase. By applying the same 10Be production rate to other Egesen moraines previously dated in the Alps, we obtain similar ages for all of them. This suggests a synchroneity of the Egesen deglaciation in the European Alps at the end of the Younger Dryas. From the palaeoshape of the Egesen glacier, reconstructed by means of geomorphological mapping, an Equilibrium Line Altitude depression (dELA) of 520 to 530 m, with respect to the present-day ELA, and of 260 to 320 m, with respect to the Little Ice Age ELA, has been calculated. Comparison with other Alpine sector dELAs indicates that the Maritime Alps experienced humid climatic conditions during the Younger Dryas
Exposure age dating and Equilibrium Line Altitude reconstruction of an Egesen moraine in the Maritime Alps, Italy
PAPPALARDO, MARTA;RIBOLINI, ADRIANO;
2008-01-01
Abstract
Four boulder samples from the Piano del Praiet frontal moraine in the Gesso della Barra Valley (Maritime Alps) have been 10Be dated. The results give a weighted mean age of 11 340370 (870) yr, constraining the frontal moraine to the Egesen glacial stadial, during the Younger Dryas cold phase. By applying the same 10Be production rate to other Egesen moraines previously dated in the Alps, we obtain similar ages for all of them. This suggests a synchroneity of the Egesen deglaciation in the European Alps at the end of the Younger Dryas. From the palaeoshape of the Egesen glacier, reconstructed by means of geomorphological mapping, an Equilibrium Line Altitude depression (dELA) of 520 to 530 m, with respect to the present-day ELA, and of 260 to 320 m, with respect to the Little Ice Age ELA, has been calculated. Comparison with other Alpine sector dELAs indicates that the Maritime Alps experienced humid climatic conditions during the Younger DryasI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
