TRACE FOSSILS IN THE CRETACEOUS-EOCENE FLYSCH OF THE SINOP-BOYABAT BASIN,* CENTRAL PONTIDES, TURKEY Alfred UCHMAN1, Nils E. JANBU2 & Wojciech NEMEC2 1 Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland;
[email protected] 2 Department of Earth Science, University of Bergen, Allegaten 4, N-5007 Bergen, Norway;
[email protected]; wojtek. nemec@geo. uib. no Uchman, A., Janbu, N. E. & Nemec, W., 2004. Trace fossils in the Cretaceous-Eocene flysch of the Sinop-Boyabat Basin, Central Pontides, Turkey. Annales Societatis Geologorum Poloniae, 74, 197-235. Abstract: Sixty six ichnotaxa have been recognized in Barremian-Lutetian deep-marine deposits of the Sinop- Boyabat Basin, north-central Turkey, which evolved from a backarc rift into a retroarc foreland, with two episodes of major shallowing. The blackish-grey shales of the ęaglayan Fm (Barremian-Cenomanian) contain low- diversity traces fossils of mobile sediment feeders influenced by low oxygenation. One of the oldest occurrences of Scolicia indicates early adaptation to burrowing in organic-rich mud. The “normal” flysch of the Coniacian- Campanian Yemięlięay Fm bears a low-diversity Nereites ichnofacies influenced by volcanic activity. The Maastrichtian-Late Palaeocene carbonate flysch of the Akveren Fm contains a Nereites ichnofacies of moderate diversity, which is impoverished in the uppermost part, where tempestites indicate marked shallowing. The overlying variegated muddy flysch of the Atbaęi Fm (latest Palaeocene-earliest Eocene) bears an impoverished Nereites ichnofacies, which is attributed to oligotrophy and reduced preservation potential. The sand-rich silici- clastic flysch of the Kusuri Fm (Early-Middle Eocene) bears a high-diversity Nereites ichnofacies, except for the topmost part, where tempestites and littoral bioclastic limestone reflect rapid shallowing due to the tectonic closure of the basin.