engleski

Cave monitoring supports selection an appropriate sampling site for paleoclimate research.

A Hungarian-Croatian joint project is dedicated to environmental changes on karstic sites with special attention to recent processes. In the framework of this ongoing project we investigate reflection and reaction of recent climate change on karstic deposits. Five water dripping site were monitored for two year in the Csodabogyós Cave (Hungary) for stable H and O isotope study in the depth of 15 to 40 m. According to the water volume measurements there is no obvious relationship between the seepage water quantity and the precipitation amount, as it was confirmed by the small variability in the isotopic composition, showing no seasonal signals. Slow dripping sites (3) with possible diffuse recharge pathway were selected for temperature monitoring as well. The measured values (9.8 and 9.4 °C) and stable O isotope values (-10.3‰ to -9.8‰ ±0.1 ‰) were constant during the period studied. The observed small differences between the sites indicating complexity in karst architecture. Additionally, recent carbonate formation (e.g. the very top of actively growing stalagmites) were sampled for stable C and O isotope study. The measured 18Ocalcite values (21.9 to 21.5‰ V-SMOW) were plotted together the recorded temperature data and the 18Owater values and resulted a narrow range at, at or within the error range of theoretical equilibrium line. The data presented here suggest that the overall variability within the cave for climate-related factors are small, thus the Csodabogyós Cave may exhibit suitable stalagmites for high-resolution paleoclimate proxies developed close to well studied selected drip sites. Our studies underlies the importance of well established in-situ monitoring and geochemical investigations before sample collection to increase the robustness of paleoclimate records. This study was financially supported by the Hungarian Scientific Research Fund (OTKA T 049713), the Croatian scientific project (119-0000000-1299) and by the Hungarian Croatian Cooperation Programme (CRO-04/2006). This paper is a contribution to the Millennium Project (EU-017008).

cave monitoring; stable isotope; paleoclimate; Csodabogyós Cave; Hungary

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