Proposal of a geomorphosite for a small glacial valley on the northeastern flank of the Mount Etna volcano (Sicily)

Abstract

Mount Etna is the largest active volcano of Europe and the highest mountain (about 3,330 m a.s.l.) of peninsular and insular Italy; moreover, during the Last Glacial Maximum (LGM, 25,000 ÷ 14,000 years BP) it was some hundreds meters higher than today. Since other mountains of the Apennines were covered by glaciers during the Upper Pleistocene, several authors hypothesized that a glacial cover could have been also present on Mount Etna during the LGM, being the estimated limit of perpetual snow around 2,500 m a.s.l. at that time and latitude. We have carried out a morphological survey in a portion of the volcanic edifice where rocks older than the LGM outcrop. This portion includes Punta Lucia, on the NW slope, and Serra delle Concazze, on the NE slope. Along the upper part of the northeastern slope of Etna we have found a small valley, about 170 m long, 15 m wide and 7 m deep, characterized by a clear U-shaped section, that we interpreted to be of glacial origin. The search for moraine deposits that could be ascribed to the activity of the hypothesized glacier was unsuccessful so far and is also complicated by the presence of vegetation and recent lava and tephra deposits covering the volcano flanks. We are aware that this valley should be considered as a possible geomorphosite to guarantee its preservation and further study.