Facies and Depositional Sequences of the Asmari Formation, Shajabil Anticline, North of the Izeh Zone, Zagros Basin, Iran

Abstract

AbstractOutcrop and microscopic studies have been applied in this research paper in order to find out the Asmari Formation depositional sequences in the Shajabil Anticline section located at the north of the Izeh Zone, Zagros Basin, Iran. Five depositional sequences were identified based on 11 facies types (bioclast Nummulitidae Lepidocyclinidae packstone, bioclast perforate foraminifera Nephrolepidina Miogypsinoides wackestone‐packstone, bioclast perforate foraminifera Corallinacea wackestone‐packstone, bioclast echinoid Neorotalia Brachiopoda wackestone‐packstone, coral floatstone‐rudstone, bioclast Corallinacea imperforate foraminifera wackestone‐packstone, bioclast imperforate foraminifera Archaias wackestone‐packstone, bioclast imperforate foraminifera Dendritina wackestone‐packstone‐grainstone, bioclast imperforate foraminifera Borelis wackestone‐packstone and very fine sandy mudstone) corresponding to the tidal flat, restricted and semi‐restricted lagoon and open marine environments of an inner and middle shelf areas.Well‐exposed outcrop horizons of Thalassinoides at the study section are a favorable tool for the regional outcrop sequence stratigraphy. Thalassinoides is considered as an outcrop key‐bed for recognition of the Rupelian‐Chattian maximum flooding depositional sequence. Coral remnants (small colonies) in outcrop exposures also are associated with the HST depositional sequence (Chattian) for the Asmari Formation. The most important achievement of this research is use of associated maximum flooding surfaces (Pg30, Pg40, Pg50, Ng10 and Ng20) in the Arabian plate. These maximum flooding surfaces could be recorded as an isochrones surface.