Reconstructing Late Pleistocene glacier dynamics in the Southern Carpathians (Romania) with the Parallel Ice Sheet Model

Reconstructing interactions between past glaciers, climate and topography over millennial timescales is crucial for predicting their dynamics 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 the growth, fluctuations and decay of large ice sheets and smaller mountain glaciers in Europe but the Southern Carpathians (Romania) have not been examined widely in this context.

Here, we present the first application of a palaeoclimate-driven, dynamic numerical ice model (Parallel Ice Sheet Model) to the Southern Carpathians. Focused on the Retezat-Godeanu mountain group, our aim is to simulate the extent, style, dynamics and climatic/topographic drivers of former glaciers in the region. Using a range of static and dynamically evolving simulations, we found that 1) the model could adequately grow plateau icefields and ice domes that match well with geomorphological evidence for ice extent in the region; 2) a significantly colder (-5°C…-8°C temperature deviations from the present) and drier (45%....15% of modern precipitation amounts) climate was required to grow palaeoglaciers to their maximum extents; 3) the model adds glaciological context to the geomorphological data by identifying where ice was slow- vs fast-moving, cold- vs warm-based, and aids interpretation of geological samples potentially containing inherited ¹⁰Be cosmogenic nuclides. Finally, by simulating a more muted response of glaciers to palaeoclimate during the Younger Dryas (12.9 - 11.7 ka), we find that it is possible that the Southern Carpathians could have supported limited ice at that time, suggesting where geological evidence for such ice could be sought.