Maastrichtian-Thanetian planktonic foraminiferal biostratigraphy and remarks on the K-Pg boundary in the southern Kocaeli Peninsula (NW Turkey)

Sarigul V., Hakyemez A., Tüysüz O., Can Genc Ş. C. , YILMAZ İ. Ö. , Özcan E.

Turkish Journal of Earth Sciences, vol.26, no.1, pp.1-29, 2017 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 26 Issue: 1
  • Publication Date: 2017
  • Doi Number: 10.3906/yer-1602-23
  • Journal Name: Turkish Journal of Earth Sciences
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.1-29
  • Istanbul Technical University Affiliated: Yes


The Kocaeli Peninsula (NW Turkey) provides one of the best exposed deep marine Upper Cretaceous-Palaeocene sections in north-western Anatolia. The biostratigraphic framework from three sections, namely Belen, Bulduk, and Toylar, in the southern part of the Kocaeli Peninsula is established by means of planktonic foraminifera. A very rich planktonic foraminiferal assemblage analysed both in thin sections and washed residues records a biozonation ranging from the Contusotruncana contusa (CF6) Zone (Maastrichtian) to the Globanomalina pseudomenardii (P4) Zone (Thanetian). Although a major part of the biozones in the studied interval is clearly defined, the upper three zones (CF1-3) of the latest Maastrichtian and the P0 and P1a zones of the earliest Palaeocene cannot be recognised. These unrecorded biozones are either completely missing or occurred within a very condensed interval in the studied sections. A hardground layer characterised by oxidation and extensive bioturbation might indicate a possible biostratigraphic gap spanning the CF1-3 zones of the uppermost Maastrichtian in the Belen and Bulduk sections. In the Toylar section, on the other hand, the CF1-3 zones still cannot be detected although a hardground layer is not observed. The biostratigraphic resolution across the Cretaceous-Palaeogene (K-Pg) boundary in the studied sections cannot be improved due to the condensed and well-cemented pelagic carbonates of the boundary interval.