Biostratigraphic analysis across the Eocene–Oligocene boundary in the southern Hellenic Thrace basin (Lemnos Island, north Aegean Sea)

Abstract

The time interval of the sedimentation in the southern Hellenic Thrace Basin (Lemnos Island, northeast AegeanSea) was studied, based on the qualitative analysis of calcareous nannoplankton and quantitative analysis of planktonicforaminifera. The samples were collected from 4 different stratigraphic sections (Ifestia, Panagia, Kaspaka, and Kaminia).The biostratigraphic analyses on both calcareous nannoplankton and planktonic foraminifera reveal an age of LateEocene–Early Oligocene (Priabonian–Rupelian). In particular, the Eocene–Oligocene boundary is recorded at the lowerpart of the turbiditic system, in the Ifestia section. The present study offers the first taxonomic analysis of planktonicforaminifera of this age in the Hellenic southern Thrace Basin (Lemnos Island). The species Catapsydrax unicavus,Chiloguembelina cubensis, Dentoglobigerina sp., Dipsidripella liqianyui, Globigerina officinalis, Paragloborotalia nana,Turborotalia cerroazulensis, and Turborotalia sp. were identified. Furthermore, D. liqianyui adds new data worldwide, as itis identified in the Mediterranean Sea (Lemnos Island) for the time interval of the O1–O4 zones (Early Oligocene).