New contribution to the biostratigraphy of Naopurdan limestone unit (Eocene), Bulfat area, Sulaimaniyah, Kurdistan Region, NE Iraq

Abstract

Abstract Forty- nine samples were collected for a biostratigraphic study of the Naouprdan limestone unit to determine the age of its strata. The studied section is located within the Zagros High Fold and Thrust Belt. The lithology of the succession here is composed of grey fine-grain of limestone with Nummulites and Alveoloina, the whole section is highly deformed and fractured. Hence, for the first time, this limestone unit describes in detail; it is a 48m bed of grey fine-grain, Alveolinidae-Nummulitidae limestone. It bears a frequent number of large benthic foraminifera that are concentrated within the limestone bed. It is detected within the Naopurdan succession from the Bulfat area, Sulaimaniyah, Kurdistan Region/northeastern Iraq. The identified-benthic foraminifera is of the groups: Nummulitidae; Alveolinidae; Acervulinidae; Acervulinidae; Rotaliidae; Linderinidae; Linderinidae; Hauerinidae; Textulariidae; Textulariidae. A detailed study of the benthic foraminiferal assemblages of the limestone unit revealed the occurrences of (104) species of benthic foraminifera belonging to (11) genera. The stratigraphic distribution of these species permits the recognition of four biozones. These are from the lower to upper part of the section: Alveolina oblonga-Nummulites djokdjokartae Interval Zone, Nummulites djokdjokartae Total Range Zone, Nummulites fabiani Total Range Zone, and Alveolina leupoldi-Alveolina elliptica Interval Zone. This study demonstrates that the lithology of this limestone bed is equivalent to the Nummulitic Naopurdan group of the Zagros Low Fold and Thrust Belt since they have similar lithology and fossil contents. This section has not previously been described.