Biostratigraphy of large benthic foraminifera from the lower part of the Shahbazan Formation: revision of the age of the carbonate succession from the Tange Lilam section (Chenareh Anticline, Lorestan Basin)

In this study, the lower part of carbonate successions from the Shahbazan Formation in the Chenareh anticline of the Zagros sedimentary basin (SW of Iran) based on Large Benthic Foraminifera (LBF) was investigated. From this succession, five species of Alveolina are described including A. fornasinii (Checchia-Rispoli), A. schwageri (Checchia-Rispoli), A. distefanoi (Checchia-Rispoli), A. cremaea (Checchia-Rispoli), A. decastroi (Scotto Di Carlo) along with species of Rotaliids such as Gyroidinella cf. magna (Le Calvez), Lockhartia hunti (Ovey), Cuvillierina vallensis (Ruiz De Gaona), Granorotalia sp. These assemblages of large foraminifera based on the Shallow Benthic Zones (SBZ) indicate the Late Ypresian (SBZ10–SBZ11). Thus, the detailed studies on this group of foraminifera were representative of the aforementioned age from the lower part of the Shahbazan Formation (Tang-e-Leilam section) for the first time. Therefore, identifying some species, such as Alveolina along with Rotaliids of the Early Eocene (Ypresian)succession was expressive of the Shahbazan Formation into the older time units.