Dynamics of sediment formation in barová cave (Moravian Karst) during the last glacial cycle

Abstract

The last climatic cycle in the terrestrial environment is usually recorded in open loess sites. However, the frontal parts of caves often inhabited during the Palaeolithic occupation frequently provide valuable sedimentary archives. We propose that the most effective approach to studying these deposits is dual dating methods combined with micromorphology. Radiometric dating (¹⁴C and U-Th) coupled with analysis of sediment formation processes of the sedimentary record indicates that the intensive clearing of Barová Cave occurred at least by the end of the last interglacial, in MIS 4 and early MIS 3. During the period ca. 55-36 kyr BP, i.e., during the main phase of MIS 3, relatively slow sedimentation occurred in the open space in the cave, which created above underlying sediments by the previous clearance. The sedimentary record consists almost exclusively of osteological material showing signs of corrosion, including collagen depletion. This layer of osteological material is overlain by relatively thick clayey sediments, again with a number of animal bones dated consistently to MIS 3, representing a rapid erosional phase. This erosional phase is likely associated with the transition between MIS 3 – MIS 2. MIS 2 itself includes one of the coldest and driest periods of the Last climatic cycle, i. e. Last Glacial Maximum (LGM), which is represented in the cave record by redeposited loess showing signs of freezing. The onset of the Holocene is marked by a continuous layer of sinter. The combination of ¹⁴C, U-Th, and sedimentological and micromorphological analyses has proven to be an effective approach for interpreting the site's formation history and its relationship to climatic changes during the last climatic cycle.