Foraminiferal biostratigraphy of the lower Miocene Hamzian and Arashtanab sections (NW Iran), northern margin of the Tethyan Seaway

Lower Miocene strata exposed in the Khoy-Bostan Abad area (NW Iran) document marine platform environments. Paleontological and lithological characteristics of these deposits were investigated to develop detailed bio- and lithostratigraphic frameworks. The shallow marine units, composed of bioclastic carbonates in Bostan Abad and mixed siliciclastic carbonates in Khoy area, were deposited under different local tectonic regimes. Relatively diverse assemblages of benthic foraminifera from these shallow marine units were studied to establish a high resolution biostratigraphy in the context of the standard shallow benthic zonation of Western Tethys. The co-occurrence of Miogypsina intermedia Drooger and Borelis melo curdica (Reichel) characterizes Zone SBZ25, indicating a Burdigalian age as also indicated by planktonic foraminifera.