Larger benthic foraminifera and biostratigraphy of the lower Oligocene Asmari Formation: offshore and onshore southern Iran (Zagros belt)

Abstract

A relatively diverse assemblage of larger benthic foraminifera from the Asmari Formation is described based on the recovered samples from two subsurface sections, offshore and onshore, southern Iran. Due to its position in the Tethyan Seaway between the Mediterranean and Indo-Pacific, the Zagros belt as a part of theMiddle East has high significance in palaeobiogeography. The fauna is dominated by both hyaline perforated and porcelaneous forms. Eight species of larger benthic foraminifera are described, including Nummulites fichteli, N. vascus, Operculina complanata, Archaias operculiniformis, Praerhapydionina delicata, Austrotrillina striata, Peneroplis thomasi, and P. evolutus. The presence of N. fichteli and N. vascus in the absence of lepidocyclinids indicates the SBZ 21 Zone referring to a short time span restricted to early Rupelian.