engleski

Sedimentary record of Pleistocene aeolian - alluvial deposits on Vrgada Island (eastern Adriatic coast, Croatia)

Vrgada Island is situated in the central part of the eastern Adriatic coast. Upper Cretaceous limestones crop out on the surface and Pleistocene sediments cover them in some parts of the island. In this study we focus on a coastal cliff elongated in the N – S direction, situated in the northern part of the island. Aeolian- alluvial deposits, which are 12.5 m thick have been analysed. Three different facies in this succession are described. Lowermost facies A has a strong aeolian influence marked by increased silt and clay percentage and was deposited during colder climate conditions. Structureless sand in facies B was deposited from dense, cold water formed by melting snow and ice from the nearby Dinaric mountains. Bioturbated sandy facies C was probably formed during warmer climate. Unusually high percentage of augite in the lowermost part of facies A can be explained by volcanic dust input, most likely from the Roman or Campanian volcanoes in Italy. Combination of surface textures on quartz grains detected from SEM photographs indicate a short transport of sediment, no matter which mechanism) was dominant. Age correlation of possible tephra horizon from Vrgada island with confirmed tephra from Susak Island and dated ice/snow melting period from nearby mountains points to Upper Pleistocene age of sediments, most likely MIS 3 and MIS 2. The sediments from the Vrgada Island represent a transitional zone between the north Adriatic islands, where aeolian sediments dominate and the South - Eastern Adriatic archipelago, where mixed alluvial and aeolian sediments were observed.

aeolian, alluvial, sands, facies analysis, Adriatic Sea, coastal cliff

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