BIOSTRATIGRAPHY OF DAMMAM FORMATION SUCCESSION IN BOREHOLES N3 AND N15 IN AL-NAJAF AREA, IRAQ

Abstract

The Dammam Formation in S and SW of Iraq is an Eocene carbonate succession consisting of limestone and dolostone. Two boreholes are selected in Al-Najaf area to investigate its biostratigraphy. The biostratigraphy of Dammam Formation consists of 22 species belonging to 13 foraminiferal genera. Two biozones are distinguished in Dammam Formation depending on the benthonic foraminiferal genus Nummulites. Those biozones are Nummulites gizehensis range zone and Alveolina sp. – Coskinolina sp. assemblage zone. According to those biozones the age of Dammam Formation is considered to be of Middle Eocene, whereas the absence of those biozones represents Lower and Upper Eocene.