The upper-middle, upper Permian and lowermost Triassic of the Hambast region (Iran) are characterized by three principal lithologies: (1) grey limestones of late Midian/Dzhulfian (i. e., Capitanian/Wuchapingian) age, overlain by (2) reddish nodular ammonoid-bearing (Paratirolites) deep-water limestones of Dorashamian/Changhsingian, and (3) well exposed, grey thin bedded, limestones of early Triassic age. The first grey limestones contain a relatively diversified assemblage: Gymnocodium bellerophontis, Permocalculus digitatus, P. fragilis, P. tenellus, Epimastoporella (?) sp., Palaeotextularia sp., Deckerella cf. composita, Climacammina valvulinoides, C. sphaerica, Globivalvulina ex gr. bulloides, Septoglobivalvulina decrouezae, Dagmarita chanakchiensis, D. shahrezaensis, Nankinella minor, Reichelina sp., Codonofusiella kwangsiana, C. schubertelloides, Pseudodunbarula arpaensis, Hemigordiellina spp., Hemigordius schlumbergeri, Neohemigordius aff. zaninettiae, Neodiscus aff. orbicus, Nodosinelloides spp., Geinitzina spp., Pseudolangella fragilis, Calvezina sp. and Frondina permica. Other important foraminifera are Neoendothyra reicheli, Cyclogyra sp., Orthovertella shalshalensis, Reitlingeria sp., recorded respectively at the base and at the top of the sequences. The representative section of Shahreza can be subdivided into seven biozones: (1) the early Midian with Yabeina (not represented in our samples); (2) the late Midian (= late Abadehian) with Reitlingeria; (3) the latest Midian (= top of Abadeh Formation) with the local appearance of Reichelina, Codonofusiella, Pseudodunbarula and Neohemigordius; (4) the early Dzhulfian with the possible FAD of Dagmarita shahrezaensis and Frondina permica; (5) the late Dzhulfian with rare Reichelina; (6) the last biozone of Permian foraminifera (accurately subdivided by ammonoids), probably entirely Dorashamian in age; Neoendothyra is only known at the top of this zone; (7) the Triassic beds, with rare foraminifera, for instance Orthovertella shalshalensis, from the base. |
