- 1Croatian Geological Survey, Zagreb, Croatia
- 2Institute of Global Environmental Change, Xi’an Jiaotong University, China
- 3School of Geography, University of Melbourne, Australia
- 4School of Earth Sciences, University of Melbourne, Australia
- 5Department of Earth and Planetary Sciences, Birkbeck, University of London, UK
- 6Institute of Geology, University of Innsbruck, Austria
- 7Department of Geography, University of Zadar, Croatia
- 8Australian Nuclear Science and Technology Organisation, Australia
- 9Department of Climate Geochemistry, Max Planck Institute of Chemistry, Mainz, Germany
The Late Holocene is characterized by several short-term climate anomalies recorded widely in various natural climate archives. However, the lack of consensus on their temporal and spatial occurrence (Neukom et al., 2019) highlights the need for high-resolution archive data as they may provide information on the magnitude and timing of these events, helping to address the gaps in our understanding of the climate over the past two millennia. Given the scarcity of high-resolution palaeoclimate records in South Central Europe, we aim to reconstruct the climate conditions over the past ~1500 years by using multi-proxy records of a speleothem from the Nova Grgosova Cave in Croatia.
A floating lamina-based chronology was acquired and supported by 15 U-Th dates to construct an age-depth model of the NG-2 stalagmite. The model reveals several distinct growth phases. The slowest growth rate ( ̴ 0.01 mm/yr) was observed during the period corresponding to the Little Ice Age from ca. 1625 to 1830 CE and partially overlapping the Medieval Climate Anomaly, from ca. 710 to 1060 CE. In comparison, the stalagmite grew ten times faster from ca. 1060 to 1625 CE and ca. 535 to 710 CE, while the fastest growth rate was observed during the last ca. 185 years ( ̴ 0.2 mm/yr).
Cave monitoring observations revealed that speleothem growth is enhanced during the cooler part of the year due to increased infiltration and dripwater degassing in a CO2-depleted cave atmosphere (Bajo et al., 2024). Accordingly, the speleothem geochemical properties most likely reflect the cooler part of the year. The stable isotope data coupled with trace element records suggest that the condensed growth phases reflect drier and/or cooler environmental conditions. Alongside, petrographical analysis revealed alterations of crystal fabrics, which are presumably a result of seasonal changes in hydrological conditions and/or geochemical properties of the dripwater. Thin sections exhibit large columnar crystals, however, to construct a stratigraphic log, the columnar fabric was further subdivided into columnar compact, columnar open, columnar elongated, micrite and microsparite fabrics. The latter two suggest microbial activity and diagenetic origin (Frisia, 2015), which is yet to be discussed.
These findings, combined with other palaeoclimate records from South Central Europe and beyond, provide a better understanding of the spatial extent and duration of the regional climate conditions over the past two millennia.
References:
Bajo, P., Briški, M., Benutić, A., Piplica, A., Brčić, V., Marciuš, B., Palatinuš, I., Stroj, A. (2024): Seasonality in cave dripwater and air properties – implications for speleothem palaeoclimatology, Nova Grgosova Cave (Croatia). Geologia Croatica, 77(3), 243–251.
Frisia, S. (2015): Microstratigraphic logging of calcite fabrics in speleothems as tool for palaeoclimate studies. International Journal of Speleology, 44(1), 1–16.
Neukom, R., Steiger, N., Gómez-Navarro, J.J., Wang, J., Werner, J.P. (2019): No evidence for globally coherent warm and cold periods over the preindustrial Common Era. Nature, 571, 550–554.
How to cite: Palatinuš, I., Bajo, P., Brčić, V., Briški, M., Cheng, H., Drysdale, R. N., Hellstrom, J., Hopley, P., Spötl, C., Surić, M., Treble, P., Vonhof, H., and Xue, J.: Multi-proxy speleothem record from continental Croatia as an archive of Late Holocene palaeoclimate variability, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15801, https://doi.org/10.5194/egusphere-egu25-15801, 2025.
