The Italian Mountains: Glacial landforms from the Younger Dryas Stadial (12.9–11.7 ka)

Many climate proxies indicate that during the Younger Dryas the mountains of the Italian Peninsula were characterised by cold (from 4°C to 7°C less than the present local averages of annual air temperature) and arid (up to 200mm/a less than the local present averages of annual precipitation) climatic conditions. The landscape of the Apennine chain was sparsely covered by arboreal vegetation at least above 1200m a.s.l., where steppe-like species dominated. Lakes in proglacial areas and temporary lakes at various altitudes disappeared, and the level of major permanent lakes recorded a marked lowstand. Freeze/thaw cycles, wind deflation and permafrost creeping became among the dominant geomorphological processes in the mountain slopes. Some sectors of the Apennine chain were affected by the presence of small cirque glaciers which led to the deposition of modest frontal moraines, defining the Aquila Stade in the Apennine glacial chronology. Morphostratigraphic relationships between frontal moraines and a dated volcanic tephra (NYT, ~14.9cal ka BP) indicate that the Aquila Stade corresponds to the Younger Dryas. The cold and arid condition favoured the development of many rock glaciers, especially in the central sector of the Apennines.