Planktonic Foraminiferal Biostratigraphy of the Late Eocene and Oligocene in the Palmyride Area, Syria

Abstract

Three deep exploration wells in the Palmyride area (Syria) have beendrilled through Oligocene and Eocene deposits. A detailed micropalaeontological investigation has been performed on the planktonic foraminiferal assemblage from drill cuttings. Standard planktonic foraminiferal zones from P15 to P22 (E15 to O6) have been identified.The test morphology and diversity of the foraminiferal assemblageindicate a general cooling trend during the late Eocene andOligocene. The specialized Eocene forms (K-mode life strategy) suchas turborotaliids, globigerinathekids and hantkeninids become extinctin the uppermost late Eocene. The Oligocene is characterized by thedominance of cooler, opportunistic planktonic foraminifera (r-modelife strategy), such as pseudohastigerinids, chiloguembelinids, globigerinids and tenuitellids. A very low number of benthic foraminiferain late Eocene cuttings implies sedimentation in a deep, open seaenvironment. A gradual increase of the benthic foraminiferal proportionthrough the Oligocene indicates shallowing of the sedimentaryenvironment.