engleski

Polyphase kame terraces on the Island of Pag (Eastern Adriatic, Croatia)

Pleistocene unconsolidated calcareous sands and open-work gravels occur along the SW coast of the Pag Bay (Fig.1) (Eastern Adriatic). Several large sand pits within a distance of 7 km are exposing erosional remnants of an extensive sand/gravel body directly overlying steep-sloped (40-80°) narrow ridge built of Cretaceous limestones. Thes sands and gravels were interpreted as glacial-outwash deposits building an extensive kame terrace (Marjanac & Marjanac 1994). During the postglacial period these deposits were in large part eroded and partly reworked into alluvial fans (units 6 and 7, Fig. 2). Sands and gravels are preserved in thickness between 20 and about 50 m. Sedimentary units 1 to 5 (Fig. 2), recognized in the largest sand pit, represent various phases of kame-terrace development, with predominating longitudinal sediment transport of detritus washed from a valley glacier; 1- glaciofluvial deposits, 2- possibly lake infill deposits, 3- and 4- Gilbert-type deltas, 5- glaciofluvial deposits - large channel fill deposits. Units 6 and 7 are reworked kame-terrace deposits. Paleosol horizon (x) is about 10 cm thick, gray/black colored clayey sand. Tree trunk casts are visible in unit 6. Paleotransport data indicate sources in the present valley centre - where a valley glacier has been interpreted (Marjanac & Marjanac 1994) and locally from the limestone ridge. The interpreted kame terrace was at least 300 m wide with well developed fluvial system and ephemeral lakes (Fig.3). Meltwaters from the ice covered ridge transported and deposited part of the sands and gravels, namely the uppermost braided stream unit and Gilbert-type deltas. These deltas also indicate existance of an ephemeral lake on the kame terrace. Low altitude Pleistocene glaciations are still poorly known in Southern and Central Europe, and their maximal extent can be studied along the Eastern Adriatic coast, although outcrop condition make it very difficult to physically correlate section on different islands and mainland.

glaciation; kame-terraces; Adriatic; Pag Island

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