39 Ar dating of cave ice combined with pollen, cryogenic calcite and radiocarbon analyses reveals late Little Ice Age origin (Leupa Ice Cave, Julian Alps)

Abstract High-latitude or high-altitude caves often preserve ice deposits that contain valuable signals of past climate conditions, sometimes even reflecting regional and local atmospheric variability. Phases of aggradation or degradation of underground ice can also provide insights into the temporal evolution of Alpine permafrost. Such data are typically obtained from ice cores, which require a well-constrained chronological framework to be meaningful. In recent years, several dating methods have been developed or refined for glacier and ice sheet cores. However, some of these techniques have not yet been applied to cave ice. In this study, the 39 Ar dating technique using Argon Trap Trace Analysis is applied for the first time to an underground ice deposit in the southeastern Alps, specifically in the Canin-Kanin massif (Julian Alps). The results are compared with pollen markers extracted from the ice, with U-Th dating of cryogenic cave carbonates found in situ within the same ice block, and with radiocarbon ( 14 C) dating of the water-insoluble organic carbon fraction embedded in the ice. This integrated approach enabled dating the ice deposit to the end of the Little Ice Age, at the onset of the subsequent warming phase.