Glacial features on the Galicica Mountains, Macedonia: preliminary report

Abstract

Glacial features were described for the first time on the Galicia Mountains, a mountain range separating the lakes of Ohrid and Prespa in Macedonia. The geomorphological mapping of part of this range allowed to document the existence of frontal and lateral moraines, as well as trimlines, cirques and polished rocks. These glacial features allowed the reconstruction of the original topography of the glaciers that deposited the frontal moraines. The Equilibrium Line Altitude (ELA) of three different phases of expansion was calculated (ca. 1850 m, ca. 2000 m and 2130 m a.s.l.) through the Area-Altitude Balance Ratio (AABR) method, and correlated with the values available for the Balkan region and northern Greece. An attribution to Last Glacial Maximum (LGM) and Lateglacial (Oldest and Younger Dryas) was argued for the glacial phases of Galicica Mountains, in agreement with the ELAs of dated moraines in the region, as well as in the Apennines and Maritime Alps. Through the extrapolation of summer temperatures at the ELAs for the single glacial phases, the amount of precipitation needed to sustain the glaciers existence was calculated (3500-3700 mm of weq) using a well established polynomial regression. The attribution to the LGM of the lowermost frontal moraine points out to an older age for the till found well below the examined area, near the Prespa Lake shore. This indicates that a more extended glaciation phase occurred during the Middle Pleistocene.