engleski

Croatian islands karst caves - archives of environmental changes

One of the key topics in the geomorphological discussions and debates of global climate change is the dynamics of environmental reshaping. Distribution and origin of caves as well as their atmospheric conditions and sediment deposits (speleothems) provide insight into the karst topography and (paleo)environmental change. Here we present the overview of the research conducted in Croatian islands karst caves, formed in well- stratified Cretaceous limestones, which reveal paleoenvironmental changes along the eastern Adriatic coast. So far U-Th dates of twelve speleothems collected on eight locations, recorded the period from the Upper Pleistocene to the Upper Holocene, along with numerous interruptions in growth. Speleothem δ18O and δ13C variations showed that climatic events and changes in the environment of the eastern Adriatic can be registered in the isotopic composition of speleothems. Besides isotope proxy, distribution and the origin of the coastal caves have been studied in Kornati archipelago. The abundance of submerged or partially submerged caves of Kornati islands, as well as along the rest of the Croatian coast, are the result of the coastal karst inundation. Most of them are flooded or partially pits distributed up to 20 meters from the coastal zone and between 10 and 20 m above sea level. This indicates a very shallow epiphreatic and vadose zone dependent on sea level oscillations. Recent diving explorations conducted within SeaLeveL project (HRZZ-IP-2019-04-9445) presumed deposition of speleothems with phreatic overgrowth (POS), offering a new tool for studying relative sea- level changes. In addition, a 42 m deep pit in Kravljačica Bay is confirmed to be abundant in cave deposits and thus suitable for paleoenvironmental research.

islands karst caves, speleothem, environmental changes, Croatia

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