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Late Quaternary environmental changes recorded in Croatian speleothems

Within the last campaign of speleothem-based palaeoenvironmental reconstruction embraced under the REQUENCRIM (HRZZ) project, three caves were selected for the thorough multi-year monitoring and speleothem analyses – Modrič Cave in North Dalmatia, Lokvarka Cave in Gorski kotar and Nova Grgosova Cave in central Croatia (SURIĆ et al., 2018). While Lokvarka Cave speleothems evidenced frequent hydrological changes and associated depositional interruptions, Nova Grgosova and Modrič caves hosted relatively stable conditions, appropriate for the speleothem deposition without strong kinetic isotopic disequilibrium effects. Two speleothems collected from Nova Grgosova Cave appeared to be the best material in terms of U-Th dating and stable isotope (δ18O and δ13C) analyses, although they covered only the last 10 ka with minimal, but evident isotopic variations characteristic for the Holocene. On the other hand, three stalagmites from Modrič Cave offer the longest composite speleothem record on the eastern Adriatic coast, with maximum age of 365 ka. Given the relatively large δ18O and δ13C ranges (-8.16‰ – -2.97‰ and -13.11‰ – -1.00‰, respectively), it is evident that they recorded significant palaeoenvironmental changes from OIS 10 to the Recent, particularly within the OIS 10 – OIS 7, then OIS 6 – OIS 5 and OIS 4 – OIS 2 periods, as well as from OIS 1. Speleothem deposition throughout both glacial and interglacial periods stresses once again the importance of palaeoclimatological studies in Croatia due to its position and varying influences by both Atlantic and Mediterranean air masses. References: SURIĆ, M., LONČARIĆ, R., BOČIĆ, N., LONČAR, N., BUZJAK, N. (2018): Monitoring of selected caves as a prerequisite for the speleothem-based reconstruction of the Quaternary environment in Croatia. Quaternary International, 494, 263-274.

speleothems, stable isotopes, palaeoenvironment, Quaternary, Croatia

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