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Sedimentary characteristics and source of loess in Baranja (eastern Croatia)

Loess is terrestrial clastic sediment, composed dominantly of silt-sized particles formed by the accumulation of wind-blown dust. It is usually inter-bedded with soil horizons forming loess- palaeosol successions (LPS). Thickest LPS in Croatia are found in Baranja, region bounded with two big rivers, the Danube and the Drava. The results of grain-size and modal analysis provide information about source material and wind direction in different time periods during Pleistocene. Grain-size distribution is in good accordance with other loess localities in the Pannonian Basin. Garnet, epidote and amphibole mineral group are most abundant heavy minerals in samples of Danube River sediment. Comparing heavy mineral assemblage (HMF) from southern and northern LPS with that data, it is obvious that main source area for loess in Baranja is from Danube flood plain sediments. Main transport direction was from North or North-West. Nevertheless the higher concentration of amphiboles in southern and northern LPS (mean 26.3% in HMF) then in the Danube plain suggests additional source area. Western Carpathians with Neogene calc-alkaline volcanic rocks is major source for amphiboles. Alternatively those minerals could be from locally exposed volcanic and metamorphic rocks of the southward Slavonian Mts. Mt. Krndija and Mt. Papuk, which are closest to Baranja of all Slavonian Mts., consist of amphibolites. In that case, small amount of silt material for Baranja loess would be transported by WSW winds. Results obtained from sedimentological and SEM analyses show fairly good congruence with results from other LPS in the Pannonian Basin, with some differences in mineral composition which imply diversity and shifting of source area for Baranja loess during Late Pleistocene.

loess; Baranja; aeolian; heavy mineral fraction; quartz; SEM images

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