An early glacial maximum during the last glacial cycle on the northern Velebit Mt. (Croatia)

Comprehensive glacial Quaternary studies involving geochronological methods, modelling of ice topography with the support of field geomorphological and geological data in the Balkan Peninsula are relatively scarce, although there is evidence of past glaciations in several mountain ranges. Here, we present research on the extent and timing of past glaciations on the northern Velebit Mt. in coastal Croatia and inferences of the climate during that time. Based on geomorphological and sedimentological evidence and using cosmogenic 36Cl surface exposure dating of moraine boulders, we provide an empirical reconstruction of past glaciers and compare this with the Parallel Ice Sheet Model (PISM) simulations under different palaeoclimate forcings. The dating results show that the northern Velebit glaciers reached their maximum extent during the last glacial cycle before the global Last Glacial Maximum (LGM). Maximum ice extent likely correlates with Marine Isotope Stage 5-4, although the exact timing cannot be determined at this point due to poorly known site-and time-specific denudation rates. Empirical reconstruction of the maximum extent suggests that the area covered by glaciers was-116 km2. The-best fit PISM simulation indicates that the most likely palaeoclimate scenario for the glaciers of this size to form is a cooling of-8 degrees C and a 10% reduction in precipitation from present-day levels. However, the best -fit simulation does not correctly model all mapped ice margins when changes in climatological parameters are applied uniformly across the model domain, potentially reflecting a different palaeoprecipitation pattern to today. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study reconstructs the extent and timing of past glaciations in the northern Velebit Mt. in Croatia using geomorphological and sedimentological evidence, as well as cosmogenic 36Cl surface exposure dating. The empirical reconstruction suggests that the glaciers likely reached their maximum extent before the global Last Glacial Maximum, correlating with Marine Isotope Stage 5-4. The best-fit simulation indicates a cooling of 8 degrees C and a 10% reduction in precipitation for glaciers of this size to form, although uniform changes in climatological parameters do not completely match all ice margins mapped.