Abstract

This study seeks to investigate and identify Paleocene-Eocene boundary in Binak 4 subsurface section in Bushehr province and the effect of temperature changes on the behaviour of planktonic foraminifera. In order to do so, 13 genera and 46 species from Planktonic foraminifera were identified, and two assemblages comprising warm water foraminiferal assemblage and cool water foraminiferal assemblage were segregated. The study of biological events on foraminifera under investigation utilizing universal biozonation led to 5 biozone and 5 subzone segregates. According to the known fossil assemblages and the defined biozones, age in this study was considered late Paleocene (late Selandian) to latest early Eocene (Ypresian). Biostratigraphic evidences (episodic extinction in cool water foraminiferal assemblages and diversity in warm water foraminiferal assemblages) at depths of 8750-8760 (ft.) are indicative of temperature changes and introducer of a global event termed ‘Paleocene-Eocene Thermal Maximum’ (PETM) at this depth. Moreover, In view of the extinction of late Paleocene index species at depths of 8760-8770 (ft. ) and the emergence of early Eocene index species at depths of 8640-8650 (ft.), Paleocene-Eocene boundary is located at depths of 8750-8760 (ft..) in P5 biozone or P5-E1 biozone.

Keywords: Paleocene-Eocene boundary; Selandian; Ypresian