Holocene environment and climate in the NW White Carpathian: a multidisciplinary approach (including geochemistry, sedimentology and malacology) on Mituchovci tufa in Slovakia
Calcareous tufas are continental open-air carbonates that routinely host evidence of past environmental conditions via well-preserved faunal and floral assemblages. As they mostly comprise of calcite precipitated at ambient temperature, tufas are also suitable targets for geochemical research, especially concerning oxygen and carbon isotopes, and thus palaeoclimatic reconstructions. At Mituchovci in the Slovakian NW White Carpathians, a ca. 3 m-high tufa deposit has been extensively studied since 2010. The profile covers most of the Holocene as supported by 10 radiocarbon dates (from 9980±40 to 210±20 yr BP) and a detailed depth-age model (created in OxCal 4.2.4). Accumulation rates estimated from this age-depth model together with lithological/sedimentological information (especially CaCO3 content) provide preliminary assumptions on long-term climate and environment dynamic: e.g. maximal calcite precipitation between ca. 8 and 6.5 ky cal. BP suggests optimal conditions for tufa development (warm and wet). The Mituchovci tufa also provides abundant palaeoenvironmental data from a detailed continuous malacological record completed by plant macrofossil and pollen analyses. They show the progressive expansion of vegetation from ca. 11.3-11.0 ky cal. BP to a maximal development between 8.6 and 6.6 ky cal. BP. After this optimum, human activities increasingly impact the forest cover. From 500 years cal. BP, all biomarkers suggest that the site was entirely deforested and maintained as a meadow. Parallel, geochemical data (including calcite δ18O and δ13C, and Mg/Ca ratio) provide independent palaeoclimate reconstructions showing strong correlations with the palaeoenvironmental records. Some short-term climate variations to drier and cooler conditions are also well recorded in the Mituchovce geochemical signal. Those multidisciplinary data allow discussing (1) the potential effects of some globally significant Holocene rapid climate changes (especially the 8.2 ky event and the Little Ice Age) and (2) the increasing impact of human activities on the White Carpathian environments.