Last deglaciation in the central Balkan Peninsula: Geochronological evidence from the Jablanica Mt. (North Macedonia)

Abstract

Several studies applied numerical age determination methods to examine glacial phases of the central Balkan Peninsula. However, the resulting datasets are contradictory, meaning that further discussion is needed. This study provides 10Be cosmic ray exposure (CRE) ages of a succession of glacial landforms in the Jablanica Mt. (North Macedonia), aiming at a better understanding of Late Pleistocene glacier development in the area. On the basis of the mapped glacial landforms, six glacial stages were identified and their mean equilibrium line altitudes (ELAs) were estimated. The CRE ages of five glacial stages - from the second oldest to the youngest - were determined between 16.8+0.8/−0.5 ka and 13.0+0.4/−0.9 ka. Accordingly, the most extensive glaciation in the Jablanica Mt. occurred before ~17 ka. The average ELA of the glaciers was 1792 ± 18 m a.s.l. during the largest ice extent, and 2096 ± 18 m during the last phase of the deglaciation.Independent reconstructions of key climatic drivers of glaciological mass balance suggest that glacial re-advances during the deglaciation were associated to cool summer temperatures before ~15 ka. The last glacial stillstand apparently resulted from a modest drop in summer temperature coupled with increased winter snow accumulation. In the study area no geomorphological evidence for glacier advance after ~13+0.4/−0.9 ka could be found. On the basis of independent climate proxies we propose that the last glacier advance occurred no later than ~13 ka, and glaciers were withdrawing during the Younger Dryas when low temperatures were combined with dry winters.