engleski

Stable isotope records of the speleothems from the eastern Adriatic islands caves

There are many systematic studies of stable isotopes in speleothems used to get proxy records of past climate changes in the Mediterranean region, as well as in Europe. Croatia encompasses a large part of Eastern Adriatic region and therefore has an important role in understanding the paleoenvirenmental changes in the Adriatic and Mediterranean region. Despite that fact, there are not many investigations on reconstructing the palaeoclimate and palaeoenvironmental changes using the speleothem records in Croatia. Here we present the results of stable isotope variations in speleothems collected from Strašna peć, located on Dugi otok Island in the central part of the Croatian Adriatic, and Mala špilja cave and Vela špilja cave, located on Mljet Island in southern part of the Croatian Adriatic. High resolution oxygen and carbon isotopic record of U-Th dated stalagmites provided an insight to Holocene period from 9.8 to 1.5 ka along with interruptions in growth. Stable isotope measurements conducted on speleothem subsamples, revealed frequent fluctuations and abrupt changes in δ18O and δ13C values expressed in a number of peak values. Periods of relatively rapid growth are associated with relatively low δ18O and δ13C values. Mid- Holocene climate is characterized by fluctuations between relatively wet and relatively dry conditions. The general trend of increasing δ18O and δ13C and reduced growth rate in Late Holocene indicates warming trend and/or the occurrence of dry climatic conditions in the paleoenvironment of the eastern Adriatic. In addition saw tooth pattern of high and low δ18O and δ13C values indicate alteration of wet and dry periods that are characteristic for late Holocene speleothems from Europe and the eastern Mediterranean.

isotopes; speleothems; Holocene; paleoenvironment; Eastern Adriatic

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