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Lower Miocene sediments from a previously not investigated outcrop of the Qom Formation (Central Iranian Basin) were studied for their foraminiferal and calcareous nannofossil content. The studied stratigraphic record is assigned to the upper part of calcareous nannofossil NN2 Zone/CN1c Subzone and to the benthic foraminiferal Borelis melo melo Zone of Burdigalian age. The diversity indices, benthic foraminiferal morphogroups, and quantitative investigation of assemblages (principal component and cluster analysis) suggest an overall shallow-marine depositional environment. This interpretation is well constrained based on the dominance of the B1 benthic foraminifera morphotype with biconvex, trochospiral calcareous test, and epifaunal habitat. The identified six cluster groups of benthic foraminiferal assemblages are confirmed by the principal component analysis too, and their distribution along the studied section argue for dynamic changes of the environment. This is well exemplified by a more or less constant shallowing, then deepening trend of the environment as revealed by the shifting from the high diversity, shallow-shelf assemblages of Cluster 5 and 6 toward the low diversity, near-shore Ammonia tepida and Porosononion subgranosus assemblage (Cluster 1), and back. [ABSTRACT FROM AUTHOR]

The Mississippian successions of the Alborz tectonostratigraphic zone have been studied in several sections (Dozdehban, Naserabad, Shahmirzad, and Mighan) extending from north to southeast. The sedimentological data indicate three main facies associations (FA): (FA1) a basin to distal outer ramp of low‐energy, low‐oxygen environment with low bioturbation and less developed in situ fossils; (FA2) a middle ramp facies accompanied by storm‐induced sediments (tempestites), echinoderm‐dominated mud mounds, and high fragmentation of skeletal components; and (FA3) an inner ramp facies, represented by sand shoal, and lagoonal/back‐barrier, mainly characterized by the dominance of oolitic, bioclast, and intraclast grainstones. The sedimentary features imply the formation of the succession on a broad flat‐topped, high‐to‐moderate‐energy shelfal carbonate ramp which had been open to the N/NE, the downslope direction, as revealed by local palaeoenvironmental reconstructions. Analysis of several proxies indicates a subtropical palaeoclimate evidenced by (a) widespread tempestite facies and occurrence of storm‐depositional processes, (b) diverse and abundant pellet‐forming thalassinoideans and burrowing echinoids trace fossil assemblages, (c) geochemical proxy indicating a palaeotemperature of 23°–25°, and (d) a rich subtropical heterozoan fossil association. The data provided here imply the palaeolatitudinal position of the Alborz Mississippian ramp is 30–40°S along the southern margin of the Palaeotethys. [ABSTRACT FROM AUTHOR]

The brachiopods from the upper part of the Mobarak Formation at the Kiyasar section in the eastern Alborz Mountains, northern Iran, have been studied in detail. Fifteen species assigned to 13 genera of Strophomenida, Orthotetida, Orthida, Productida, Athyridida and Spiriferida are described. The fauna is determined as early Viséan in age based on the presence of Eomarginifera paucispinosa, Grandispirifer mylkensis and Unispirifer sp., and their associated foraminifers Uralodiscus, Paraarchaediscus, Glomodiscus and Endothyra, though taxa ranging through the Tournaisian-Viséan are also present. A comparison of its palaeogeographical affinities with other faunas show that the Alborz brachiopod fauna maintains strong Palaeotethyan affinities based on its general similarities with those of Eurasia, North America and Australia. This is suggestive of a prevailing oceanic current that circulated between the northern and southern shelf sea of the Palaeotethys Ocean, with which the warm-water brachiopod taxa were widespread in the Palaeotethyan Realm through the early Viséan. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Four cephalopod taxa are described from the Abastu Formation at a locality near the village of Abarsaj, northern Iran. The described fauna includes Orthocerida indet,Eosomichelinocerassp.,Proterovaginoceras incognitum?andSactorthocerassp. suggesting a late Dapingian to Darriwilian (Middle Ordovician) age of the strata. The reported assemblage belongs to an open marine faunal association and its composition suggests a close affinity with those of Baltica and South China. [ABSTRACT FROM AUTHOR]

The Mobarak Formation is near the town of Kiyasar in the south-east of Sari city, northern Iran. This formation conformably overlies the Geirud Formation (Upper Devonian). The lower part of the Mobarak Formation consisting of shales and thin- to medium-bedded limestone toward the top of these sequences changes into alternations of dark limestone and interbedded gray to black shales. Weathered yellow thick-bedded shales are observed at the top of the section. This formation is covered unconformably by sandstones attributed to the Dorud Formation (Lower Permian). The thickness of the formation in this region is 250 m. Four rock units have been recognized in this section. Foraminiferal biostratigraphy shows that the age of the Mobarak Formation in the Kiaysar region ranges from Lower Tournaisian to Early Middle Visean. The foraminifer Zones FAZ1 and FAZ2 are correlated with the Lower Tournaisian and Upper Tournaisian, whereas Zones FAZ3 and FAZ4 correlate with the Visean. Affinities exist between specimens recorded in the Kiyasar section with species known from other regions in eastern and Central Alborz, but there are important differences in their appearance. [ABSTRACT FROM AUTHOR]