engleski

A multiproxy record of Holocene paleoenvironmental changes from the Pirovac Bay on the Eastern Adriatic coast

Pirovac Bay is a relatively large but shallow karst depression in the central part of the eastern Adriatic shelf. High-resolution seismic study was coupled with multyproxy (geochemical, grain-size, mineralogical and paleontological) sediment core analysis in order to reconstruct paleoenvironmental evolution of the area in relation to climate variability and the sea- level fluctuations during the Late Glacial and Holocene. Karst bedrock of Pirovac Bay is covered with up to 12 m of sediments in the deepest part of the bay. The 7.2 m long sediment core was extracted from the central part of the bay (25 mbsl) and 1.3 m long core from the NW part of the bay (6 mbsl). The longer sediment core spans to the last ~14.000 years and the oldest sediments represent the remnants of the loess-like sediments that appear in the outcrops on the surrounding islands, mostly in the south-western part of the area, evidenced by clay mineral composition. Furthermore, formation of the floodplain/alluvial fan in the bay is proposed at that time, followed by freshwater lake until 7.500 cal yr BP, with typical lake ostracod assemblage. „Karst lake” Pirovac Bay existed from 12.000 cal yr BP until 8.000 cal yr BP when the sea level rising caused it to enter into the bay and marine sedimentation began. Mo enrichment occurs in transition zone between freshwater and marine sediments indicating formation of a shallow short-lived anoxic lagoon. This study enabled us to track the changes of the bay, from alluvial, lacustrine, brackish to marine environment. The evolution of the Pirovac Bay had strong influence on the formation of the Lake Vrana, and the two lakes coexisted for about 1.000 years in the Early Holocene, before the drowning of the „karst lake“ Pirovac Bay with the climate change and the rising sea.

Paleoenvironmental changes ; Holocene ; Eastern Adriatic ; sea level rise

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