Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/include/functions1.php on line 943
Abstract:
We studied Holocene speleothems and tufa samples collected in numerous caves and rivers in the Dinaric Karst of Croatia, Slovenia, Bosnia and Herzegovina, as well as Serbia and Montenegro. Differences in the formation process of tufa and speleothems are discussed in the context of their isotopic composition (14C, 13C and 18O), as well as the chemistry of surface water (rivers, lakes) and drip water (in caves). The physical and chemical parameters monitored in the surface water (tufa precipitation) and drip water (speleothem precipitation) show that more stable conditions accompany speleothem rather than tufa formation. This is particularly obvious in the water temperature variations (2-22[deg]C in surface water and 7-12[deg]C in drip water) and in saturation index variation (3-11 in surface water and 1-6 in drip water). The range of 14C ages recorded by Holocene speleothems (~12 000 yr) is wider by several thousands years than that of Holocene tufa samples (~6000 yr). [delta]13C values for tufa samples range from -12[per mille sign] to -6[per mille sign] and for speleothem samples from -12[per mille sign] to [per mille sign] reflecting higher soil carbon and/or vegetation impact on the process of tufa than on speleothem formation. The differences in [delta]18O values of tufa and speleothem samples from different areas reflect different temperature conditions and differing isotopic composition in the water. The study shows that speleothems from the Dinaric Karst can be used as global palaeoclimatic records, whereas tufa records changes in the local palaeoenvironment