Early Oligocene Larger Foraminiferal Biostratigraphy of the Qom Formation, South of Uromieh (NW Iran)

The marine strata of the Qom Formation south of Uromieh (Baranduz) yielded a moderately diverse larger benthic foraminiferal fauna resembling the fauna already described from European marine sequences. The fauna allowed the author to correlate the larger foraminiferal assemblage of northwestern Iran with the standard shallow benthic zonation. The assemblage is dominated by hyaline and porcellaneous forms including Operculina, Nummulites, Neorotalia, Penarchaias, Victoriella, Peneroplis, Praerhapydionina, Spirolina, Halkyardia, Planorbulina, Dendritina, Borelis and Bullaveolina. This faunal assemblage is also accompanied by coralline alga Subterraniphyllum thomasii. The presence of Nummulites cf.fichteli and N.cf. vascus in the absence of Lepidocyclina allows correlation of the foraminiferal fauna of the studied section with the SBZ 21 shallow benthic zone, indicating early-middle Rupelian age. Planktonic foraminiferal data from the overlying marly succession support the assigned age using larger benthic foraminifera.