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Late Pleistocene and Holocene paleoenvironments of a submerged karst landform (Pirovac bay, Croatia)

The Pirovac Bay karst depression in central Dalmatia is up to 25 m deep is partially separated from the Adriatic Sea by a series of islands and shallow sills (< 5m). The present-day marine bay was studied using bathymetric and sub-bottom profiles to reconstruct the basin-wide sedimentation. A 7.2 m sediment core spanning the last 14.500 cal yr BP was analyzed. The seismic data identified up to 12 m of sediments in the deepest parts of the bay. Distinct seismic- stratigraphic units are interpreted as records floodplain, lacustrine environments, brackish to lagoonal environments, and finally a marine environment with a connection to the open sea. The marine-lacustrine transition was dated at 7.500 cal. yr BP using ostracod and foraminifera data. A freshwater lake was established sometime after 14.000 cal yr BP due to sea level rise and the lake was by karst springs from the neighboring Vrana polje (today Vrana lake). The karst lake in Pirovac Bay coexisted with the newly formed Vrana lake in the hinterland from 8.000 to 7.500 cal yr BP. The sea level rise plays an important role in controlling the sedimentation changes and formation of coastal lakes along the karst coast of the Adriatic Sea. There are uncertainties in timing of the freshwater/marine transition and its relation to relative sea level rise since the karst is permeable and the marine conditions could have been established before the flooding of the basin. This work was supported by the Croatian Science Foundation in the project “QMAD” (HRZZ IP-04-2019- 8505).

karst basin, karst paleolake, submerged landscape, seismic stratigraphy, late glacial, Holocene, Adriatic Sea

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