lithostratigraphy and microbiostratigraphy of the ruteh formation in northwest of khur, central alborz, iran

a sequence of permian rocks crops out in northwest of khur in central alborz, north of iran. this sequence consists of the dorud (asselian-sakmarian), ruteh (artinskian-murgabian) and nesen (early djulfian) formations. the ruteh and nesen formations in alborz range were deposited in a shallow marine environment of the continental margin in the paleo-tethys. the ruteh formation with a thickness of 221m unconformably overlies the dorud formation and consists of fossiliferous limestones. this formation in the studied section can be subdivided into three informal members and overlain disconformably by the nesen formation (early djulfian). this sequence is disconformably overlain by the elikah formation (scythian-ladinian). the rich foraminiferal fauna indicates an artiniskian to early djulfian age of the succession that can be established with the schubertella-mesoschubertella assemblage zone (artinskian), dunbarula-deckerella and neoendothyra-pachyphloia assemblage zones (murgabian), and paraglobivalvulina-ichtyolaria assemblage zone (early djulfian).