engleski

Radiocarbon in environmental and palaeoclimate investigations in the Dinaric karst

Dinaric karst is the region in Croatia formed largely of sedimentary rocks of limestone and dolomite. It spans along the coast of the Adriatic Sea in northwest-southeast direction. It covers half of the Croatian territory, including islands and coast, high mountain region, partly central Croatia, and vast part submerged by the sea. The karstic forms such as tufa deposits and sediments in karst lakes and rivers, terrestrial and submerged speleothems in numerous caves and marine algal rims in the coastal area present good material for studying the palaeoclimate and environment in the Dinaric karst. Precipitation of carbonate sediments (speleothem, tufa, lake sediment, algal rims) in karst region occurs from water supersaturated with calcium carbonate, but conditions of precipitations are different. Tufa formation from lake or river water is favoured where well-developed plants exist in streams resulting in different morphological forms and the isotopic equilibrium is often not established. This process is very sensitive to physico-chemical or biological changes in the water and also to seasonal fluctuation. Lake sediments are formed from lake water under more stable conditions than those of tufa precipitation, and therefore the lake sediments are more often formed under isotope equilibrium conditions. Lake sediments may provide a continuous, high-resolution record of environmental changes within the lake ecosystem and regional catchment and have been used widely to study natural environmental changes or human-induced impact. Speleothems are carbonate deposits precipitate from drip water in the caves under stable microclimate conditions and represent valuable high-resolution records of paleoclimate. Submerged speleothems as well as marine algal rims in the coastal area can be used as sea-level change indicators. An overview of the paleoclimate and environment investigation of different carbonate deposits in the karst area of Plitvice Lakes, Krka and Zrmanja river, several caves and coastal area of Adriatic sea using carbon isotope analyses (14C and 13C) will be presented. The project Reconstruction of the Quaternary environment in Croatia using isotope methods financed by Croatian Science Foundation will be also presented.

radiocarbon ; Dinaric karst ; tufa ; lake sediment ; speleothem ; algal rims

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