Biostratigraphy of Yamama Formation in selected wells, Southern Iraq

The present study focuses on the biostratigraphy of the Yamama Formation in three wells (X, Y, and Z) distributed across two fields. A total of 205 thin-section slides, derived from core and cutting samples, were integrated to delineate the stratigraphic framework of the Yamama Formation, spanning multiple biozones. These include two benthic foraminifera zones: the Pseudocyclammina lituus Partial Range Zone and the Praechrysalidina infracretacea Taxon Range Zone, as well as two species of green algae from the family Dasycladaceae: the Salpingoporella dinarica Partial Range Zone and the Cylindroporella sugdeni Partial Range Zone. The age of the Yamama Formation is determined by index fossils that appear during the Early Cretaceous (Berriasian–Valanginian), based on benthic foraminifers and calcareous green algae.