Last deglaciation in the central Balkan Peninsula: geochronological evidence from the Jablanica and Jakupica Mts (North Macedonia)

<p>Several studies applied numerical age determination methods to examine glacial phases of the central Balkan Peninsula. However, the resulting conflicting datasets require further discussion. This study provides <sup>10</sup>Be Cosmic Ray Exposure (CRE) ages of a succession of glacial landforms in the Jablanica and Jakupica Mts (North Macedonia), aiming at a better understanding of Late Pleistocene glacier development in the area.</p><p>In the Jablanica Mt. (~41.25° N; Crn Kamen, 2257 m a.s.l.) six glacial stages were identified (Temovski et al., 2018). The CRE ages of five glacial stages (from the second oldest to the youngest) range from 16.8<sup>+0.8</sup>/<sub>-0.5</sub> ka to 13.0<sup>+0.4</sup>/<sub>-0.9</sub> ka. Accordingly, the most extensive glaciation in the Jablanica Mt. occurred before ~17 ka (Ruszkiczay et al., 2020).</p><p>Based on the accumulation area balance ratios (AABR) of the reconstructed glaciers, their mean equilibrium line altitudes (ELAs) were estimated. The average ELA of the glaciers was 1792±18 m a.s.l. during the largest ice extent, and 2096±18 m a.s.l. during the last phase of the deglaciation.</p><p>Independent reconstructions of key climatic drivers of glaciological mass balance suggest that glacial re-advances during the deglaciation in the Jablanica Mt. were associated to cool summer temperatures before ~15 ka. The last glacial stillstand may result 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<sup>+0.4</sup>/<sub>-0.9</sub> ka could be found. Relying on independent climate proxies we propose that (i) the last glacier advance occurred no later than ~13 ka, and (ii) the glaciers were withdrawing during the Younger Dryas when low temperatures were combined with dry winters.</p><p>In the Jakupica Mt. (~41.7° N, Solunska Glava, 2540 m a.s.l.) a large plateau glacier was reconstructed. The study area comprised six eastward facing, formerly glaciated valleys. Cirque floor elevations range from ~2180 m a.s.l. at Salakova Valley, to between ~2115 and ~2210 m a.s.l. on the carbonate plateau. The lowest mapped moraines are descending down to 1550-1700 m a.s.l. Due to the large plateau ice and the complicated system of confluences, glacier reconstructions using semi-automated GIS tools are problematic. Four to six deglaciation phases were reconstructed, and a preliminary estimation of the ELAs based on the maximum elevation of the lowermost lateral moraines leads to ELA values of 1800±50 m a.s.l. for the most extended phase. Multiple CRE ages for the subsequent glacial stages are also being acquired for Jakupica Mts.</p><p>This research was supported by the NKFIH FK124807 and GINOP-2.3.2-15-2016-00009 projects, by the INSU/CNRS and the ANR through the program “EQUIPEX Investissement d’Avenir” and IRD and by the Radiate Transnational Access 19001688-ST.</p><p>Ruszkiczay-Rüdiger Zs., Kern Z, Temovski M, Madarász B, Milevski I, Braucher R, ASTER Team (2020) Last deglaciation in the central Balkan Peninsula: Geochronological evidence from Jablanica Mt (North Macedonia). Geomorphology 351: 106985</p><p>Temovski M, Madarász B, Kern Z, Milevski I, Ruszkiczay-Rüdiger Zs. (2018) Glacial geomorphology and preliminary glacier reconstruction in the Jablanica Mountain, Macedonia, Central Balkan Peninsula. Geosciences 8(7): 270</p>