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Comparison of Lokvarka and Nova Grgosova Cave environments (Croatia) – initial outcomes after 2-year monitoring

In order to reconstruct paleoenvironmental changes recorded in speleothems, monitoring aimed at the characterisation of cave environment has been performed in two caves located in continental part of Croatia - Lokvarka Cave (780 m a.s.l.) and Nova Grgosova Cave (240 m a.s.l.). Besides, one active and one inactive stalagmite were collected in each of the caves to produce radiometrically constrained stable isotope (18O and 13C) time series. Apparently, their growth patterns showed quite good correlation with hydrological behaviour observed during the 2-year monitoring. Drip sites in the Lokvarka Cave have had fracture-flow drip regime indicating flow paths through the relatively large fractures which resulted with quite inhomogeneous internal speleothem structures and possibly presence of Th-rich clay. Therefore, we applied AMS 14C dating. Lokvarka speleothems cover 47.8-45.6 ka BP and 42.7-12.9 ka BP time spans, the later having d18O range from -7.57‰ to -5.48‰ and d13C from -10.06‰ to -3.46‰. On the other hand, seepage flow of Nova Grgosova drip sites produced quite homogenous speleothems suitable for U-Th dating, covering Holocene i.e. 10.1-0.1 ka and 9.6-5.8 ka periods. This monitoring program and research is a part of the project 1623 Reconstruction of the Quaternary environment in Croatia using isotope methods - REQUENCRIM financed by the Croatian Science Foundation.

Speleothem ; cave ; cave monitoring ; Lokvarka Cave ; Nova Grgosova Cave ; Croatia

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