The Ostracoda assemblage of the Eocene-Oligocene transition in northwestern Thrace: Kirklareli-Edirne area (northwestern Turkey)

The aim of the study is to investigate the Eocene-Oligocene transition in detail in northwest Thrace (NW Turkey) with heavy reliance on ostracod fauna. The lithologies formed and the environmental changes during this time period were also studied.The study was carried out in northwest Thrace within the outcropping Koyunbaba, Soğucak, and Ceylan Formations; Mezardere, Osmancik, and Danişmen Formations of the Yenimuhacir Group; and the Taşlisekban and Pinarhisar members of the Danişmen Formation. Rich ostracod fauna indicating an Eocene and Oligocene age and environment are found within these units.The Ostracoda fauna identified were ostracods Triebelina punctata, Bairdia cymbula, Bairdia tenuis, Cyamocytheridea nova, Krithe bartonensis, Krithe angusta, Krithe rutoti, Krithe parvula, Echinocythereis isabenana, Leguminocythereis genappensis, Grinioneis triebeli, Xestoleberis subglobosa and Xestoleberis muelleriana from the Mid-Late Eocene epoch; Cytheromorpha zinndorfi, Hemicyprideis montosa, Neocyprideis williamsoniana, Cladarocythere apostolescui, Hammatocythere hebertiana, Haplocytheridea helvetica, Cytheridea pernota, Callistocythereis vitilis, Cushmanidea cf. scrobiculata, Pterygocythereis fimbriata, Pokornyella limbata, Grinioneis paijenborchiana, Cytheretta tracensis, Macrocypris wrightii and Paracypris bouldnorensis from the Late Eocene-Early Oligocene epoch; and Novocypris eocenana, Novocypris striata, Moenocypris forbesi, Candona (Pseudocandona) fertilis, Candona (Lineocypris) sp. and Cypridopsis soyeri from the Early-Late Oligocene epoch.The study was also correlated to previous research conducted on Eocene-Oligocene age ostracods around the area, in northwestern Europe, and in the Paris-Akiten Basin, in view of similar age-environment relationships determined by said studies.On the basis of evidence from the lithologic content of the beds and the micropaleontological investigation, the fossil community identified in this study indicates that the sea reached deeper levels in the Eocene epoch than during the Oligocene epoch. © 2016 Elsevier Ltd.Firat University Scientific Research Projects Management Unit Magyar Tudományos AkadémiaThe findings presented in this paper are drawn from the second author's PhD study titled “A Micropaleontological Investigation of the Tertiary Deposits of the Thrace Basin and Its Relationship to Tethys-Paratethys,” which is supported by the Scientific Research Projects Unit of Çukurova University (Project No. MMF 2010 D9 ). Also thanks for identifying benthic foraminifera to Prof. Dr. Niyazi Avşar within the study. Fieldwork expenses were provided from the funds of the project titled “The Tectonostratigraphic Properties of the Istranca Massif and Its Comparison with the Successions in Bulgaria,” which is being carried out by the General Directorate of Mineral Exploration and Research Institute of Turkey (MTA). Appendix