The extent, style, timing, and dynamics of past glaciation in the Southern Carpathians, Romania

Abstract

Reconstructing interactions between past glaciation, climate and topography over millennial timescales is crucial for predicting their shift under future climate change. Abrupt climate oscillations during the Last Glacial Maximum (~24-19 ka) and the Last Deglaciation (~19-11.7 ka) led to fluctuations of large ice sheets and smaller mountain glaciers in Europe. Situated at the former intersection of westerly and southerly winds, the Southern Carpathians (Romania) represent an ideal mountain range for reconstructing past climate-topography-glacier interactions. However, the region has not been systematically studied, leaving a patchy understanding of glacial geomorphology, geochronology and palaeoclimate implications. Therefore, this thesis aims to reconstruct the extent, style, timing, and dynamics of past glaciation in the Southern Carpathians.

An application of geomorphological mapping, sedimentological analyses and glacial landsystem development over the smaller Godeanu and the Iezer mountains constrained both former ice extents and glaciation styles through the first two glacier landsystem models for temperate-continental mountains: the debris-charged plateau icefield/cirque, and the rock slope failure-conditioned alpine glacier landsystems. The production of 25 new 10Be surface exposure ages in the same locations revealed a high degree of geological uncertainty, addressed through a region-wide age-elevation model to filter climatic drivers on glacial chronology from non-climatic ones. The first deployment of a time-evolving numerical ice model (Parallel Ice Sheet Model) in the region was constrained by both new and pre-existing spatial (geomorphological) and temporal (geochronological) empirical data over the larger Retezat-Godeanu mountain group over the Last Deglaciation. The model successfully recreated ice extent fluctuations in the studied valleys, allowing interpretations of regional ice dynamics, such as possible ice existence in some areas during the Younger Dryas (~12.9-11.7 ka). Thus, this thesis highlights the power of integrating empirical and modelled palaeoglaciological reconstructions to decipher the glacial history and its controls in formerly glaciated mountain ranges like the Southern Carpathians.