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    Öğe
    Biostratigraphy of the Paratethyan Neogene at Yalova (Izmit-Province, NW-Turkey)
    (Gebruder Borntraeger, 2006) Rueckert-Uelkuemen, Neriman; Kowalke, Thorsten; Matzke-Karasz, Renate; Witt, Wolfgang; Yiğitbaş, Erdinç
    Two main palaeoenvironments are reconstructed for the Paratethyan deposits at Yalova (Turkey). The investigated sections show the typical lithologic composition of the Neogene of NW Turkey, however, the palaeoecological context was so far unknown and the stratigraphic differentiation was still outstanding. In this study, molluscs, ostracods and fish remains are used as tools for the interpretations of the palaeoenvironmental situation. These biota reflect palaeoenvironments, represented by (1) the clastic section of the Kilic Formation and (2) the Yalakdere Formation, which is characterized by marl, clay and coal sedimentation. While the Kilic Formation comprises sediments of fluviatile deltaic systems, connected to lagoons with partly reduced water energy, the Yalakdere Formation exemplifies freshwater habitat, including stagnant water bodies with a seasonally slightly varying salinity and, at most, moderately flowing rivers. The investigated biota indicate a Late Miocene age of both the Kilic and the Yalakdere Formation. Some species furthermore allow a more detailed stratigraphic assignment: the Yalakdere Formation corresponds to the Late Khersonian/Early Maeotian. Comparisons with contemporaneous faunas indicate connections to the Dacian, Euxinian and Caspian Basins and a weak Mediterranean influence. No occurrences of Central Paratethyan elements of the corresponding Late Pannonian time interval are evident.
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    Öğe
    Ostracods and bivalves from an Upper Pleistocene (Tyrrhenian) marine terrace near Altinova (İzmit Province, Turkey)
    (2005) Schneider, Simon; Witt, Wolfgang; Yigitbaş, Erdinç
    Ostracods and bivalves from two samples collected near Altinova (İzmit Province, Turkey) are studied. The sample sediment consists of coarse to fine grained sands and comes from the oldest part of the Marmara Formation, a succession of Late Pleistocene marine terraces. The composition of the ostracod fauna corroborates the Tyrrhenian radiometric age of the succession. The ostracod associations are composed predominantly of heavily calcified and ornamented genera, which indicate a nearshore, inner neritic depositional environment. The bivalve assemblages, containing byssate and cementing epifaunal and infaunal taxa, suggest a combination of rocky coastal environment and shallow marine clastic deposits. Faunal composition and shell dimensions of the bivalves are indicative of reduced salinity.