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Fusulinid fauna from the late Sakmarian-early Artinskian Khan Formation in the Kalmard area, east-central Iran, was studied using morphometric techniques to test the reliability of previous taxonomic descriptions. Fusulinids in the Kalmard area have been previously grouped into three genera ( Eoparafusulina, Perigondwania, and Neodutkevitchia) and '20 species'. Results of ordination analyses (PCA and RDA) reveal that the genera are readily distinguished, whereas only a few species previously defined within the genera Eoparafusulina and Perigondwania are recognizable. This suggests that the taxonomic descriptions and measurements for different structural elements for some of these fusulinid species are not sufficient to justify erecting separate taxonomic names. Since fusulinids are really important fauna for biostratigraphic and palaeobiogeographic interpretation in the late Palaeozic, defining species based on quantitative analysis of their morphological structures should be more accurate and improve the quality of regional correlations. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The limestone of the Ruteh Formation of Upper Permian age in the Kanigorgeh district (northeast of Bukan, NW Iran) contains several layers and lenses of bauxitic ores. Mineralogical data show that this limestone consists of calcite and quartz as major and plagioclase, kaolinite, and hematite as minor mineral phases. Geochemical analyses reveal that the proportions of ΣREEs (La-Lu) in this limestone vary from 35.28 to 160.78 ppm. The values of Eu and Ce anomalies (normalized to PAAS) of the limestone have ranges of 1.11-1.68 and 0.89-1.16, respectively. The high values of ΣREEs; low values of Y/Ho; strong and positive correlations between ΣREEs and elements such as Si, Al, Ti, V, Co, Ni, Rb, Cu, and Nb; and negative correlations between CaO and ΣREEs suggest that the observed variations in values of ΣREEs in the limestone were controlled principally by the quantity of detrital materials. Geochemical data also illustrate that the observed positive Eu anomalies in the limestone may be due to the presence of plagioclase and also a function of diagenetic processes. Furthermore, the variations in Ce anomalies may be due to the detrital input. The distribution of REEs (normalized to chondrite) illustrates different patterns in both rocks (the limestone and the bauxitic ores) in light of differentiation degree of LREEs from HREEs and values of conservative indexes such as Eu anomaly. Considering these pronounced discrepancies, it appears that the limestone, despite having relatively high concentration of ΣREEs, did not play a significant role in supplying lanthanides for the bauxitic ores. [ABSTRACT FROM AUTHOR]

Recovery from the Late Permian mass extinction was slowed by continued environmental perturbations during the Early Triassic. Rapid fluctuations of the Early Triassic marine carbonate carbon isotope record indicate instability in the global carbon cycle, and recent δ18Oapatite studies link elevated temperatures to the prolonged biotic recovery. High temperatures potentially caused enhanced continental weathering that was detrimental to marine ecosystems, but linking weathering rates to temperature has proven difficult. One proxy for weathering is the 87Sr/86Sr of marine carbonate; we present here an 87Sr/86Sr record from an upper Permian-lower Triassic succession near Zal, Iran, that is coupled to a δ13Ccarbonate record. An increase in the rate of 87Sr/86Sr rise from the Dienerian to the Smithian may be linked to elevated continental weathering rates caused by warming during the Smithian. [ABSTRACT FROM AUTHOR]

Abstract: Large carbon cycle perturbations are associated with the end-Permian mass extinction and subsequent recovery, but Late Permian (Lopingian) carbon cycle dynamics prior to the mass extinction event remain poorly documented. Here we present a high-resolution δ13Ccarb chemostratigraphic framework from latest Guadalupian to earliest Triassic time, calibrated with high-resolution conodont biostratigraphy and high-precision geochronology. We observe two large negative excursions in δ13Ccarb, the first in uppermost Guadalupian strata and the second at the end of the Changhsingian stage, and between these events distinctive excursions from the middle Wuchiapingian to the early Changhsingian. The end-Changhsingian excursion represents a major reorganization of the global carbon cycle associated with the end-Permian mass extinction. However, the extent to which the end-Guadalupian and Wuchiapingian/Changhsingian boundary excursions result from local versus global controls remains unresolved. Regardless of their underlying causes, these three excursions provide chemostratigraphic markers for global correlation of Lopingian strata. [Copyright &y& Elsevier]

[Display omitted] • The Iranian bauxites are related to tectonic and palaeogeographic environments. • The Permian–Triassic bauxites correspond to the rift and drift of Cimmeria. • The Triassic–Jurassic bauxites are linked to the collision of Cimmeria and Eurasia. • The Late Cretaceous bauxites are related to arc–continent collision. The Iranian karst bauxite deposits formed in northwestern Iran, the Alborz Mountain Chain, Central Iranian Plateau, and Zagros Simply Folded Belt during warm periods of the middle–late Permian, Permo–Triassic, middle–late Triassic, late Triassic–early Jurassic, and late Cretaceous. According to the literature, mafic igneous and argillaceous carbonate rocks have been considered to be a source rock for these deposits. We show here that, according to palaeogeographic reconstructions, bauxite deposits are directly linked to the tectonic settings of the Iranian area through time. From the middle–late Permian to the late Triassic, the formation of the Iranian karst bauxite deposits coincides with the uplift of the rift and passive margin shoulders, and their disappearance through the subsequent thermal subsidence and sea-level rise. The occurrence of bauxite deposits in the late Cretaceous is coeval with relief formation associated with the arc–continent collision and obduction of the Semail plate with the Arabian margin. The present study supports the idea that palaeogeographic reconstructions can potentially be used as predictive tools for the possible occurrence of bauxites elsewhere in time slices when climatic prerequisites of bauxite formation prevailed. [ABSTRACT FROM AUTHOR]

The Late Permian marine sequence in the northwest of Iran, in eastern Azerbaijan province in the Zal stratigraphic section, was selected for studying brachiopods. Samples were collected from the Ali Bashi and Jolfa Formation.S. Twenty-seven species from 13 brachiopoda genera were recognised in this study.The recognised fossil community was compared to brachiopod communities in some regions of Iran and the Tethyan region, suggesting the Late Dzhulfian period as the age for the deposits being studied. Recognized brachiopods belonge to the orders Athyris, Rhynconellida, Productida and Strophomenida.Keywords: brachiopoda, Late Permian, Iran. [ABSTRACT FROM AUTHOR]

A diverse Late Permian assemblage of chondrichthyan and actinopterygian micro- and macroremains is presented from the central Iranian locality of Baghuk Mountain for the first time. The vertebrate remains were found in sediments containing mainly pelagic organisms such as nautiloids, ammonoids, and conodonts. Their habitat is interpreted as a deep shelf area with well-oxygenated bottom water conditions below the storm wave base. The chondrichthyans are represented by various dermal denticles, a fragment of a spine, and a low number of teeth from mostly durophagous hybodontiforms and eugeneodontiforms. A new eugeneodontid species is described as Bobbodus xerxesi sp. nov.; this genus was known only from the east coast of the former Panthalassic Ocean. The actinopterygian remains are represented by dermal bones, teeth, and scales. The bones are only fragmentarily preserved. The Baghuk Mountain vertebrate fauna shows closest similarities to remains known from the Russian Platform and from localities situated at the east coastal region of the Panthalassic Ocean (central United States). [ABSTRACT FROM AUTHOR]

Six assemblages of smaller foraminifers are first distinguished and described from sections of the Kalmard tectonic block, Central Iran. The assemblages that have been studied are correlated with concurrent assemblages from the East European platform, Cis-Urals, Darvaz, Northern Pamir, and some other regions of the Tethyan Realm. The results of correlation and available data on fusulinids and conodonts occurring in association with smaller foraminifers are used for dating the assemblages whose distribution ranges span the stratigraphic interval from the early Sakmarian (lower assemblage) up to the Kubergandian (uppermost assemblage). New species Frondina iranica sp. nov. discovered in the study region is described. [ABSTRACT FROM AUTHOR]

The Iranian territory is composed of a mosaic of tectonic units, several of which underwent in the Permian and Triassic periods a migration from northern Gondwana to southern Laurussia associated with the opening of the Neo-Tethys Ocean. Although this broad outline of Permo-Triassic palaeogeographical evolution of Iranian microplates is now widely accepted, the individual timing of migration of these blocks, and their biogeographical relationships, remain insufficiently known. Here I review the Late Palaeozoic record of trilobites in Iran and Armenia, and discuss their palaeobiogeographical affinities in an attempt to shed light on the Permian palaeogeographical evolution of Iranian and Armenian terranes. Seven Iranian or Armenian localities, representative of five tectonic units, have yielded Carboniferous and Permian trilobites. Ten species are recognized, including two new taxa, Persia praecox gen. nov. sp. nov. and Pseudophillipsia (s.l.) parvizii sp. nov. P. praecox is the only Carboniferous (Tournaisian) species. The others are Wordian to Wuchiapingian in age and can be separated into three morphological groups, probably representing clades. One is composed of representatives of Acropyge, while the two others (armenica-group and paffenholzi-group) comprise species of Pseudophillipsia. Only P. (s.l.) parvizii sp. nov. from the Zagros Mountains (Arabian Plate) is not attributed to one of these groups. The distribution of trilobites in Iran and Armenia strongly suggests that the Alborz, Central Iran and Transcaucasia microplates represented a single biogeographical unit in Middle and Late Permian times. Special relationships of this biochore with South China can also be stressed. [ABSTRACT FROM AUTHOR]

Abstract: The Sanandaj–Sirjan metamorphic–plutonic Belt (SSB) in west central Iran is a polyphase metamorphic terrain composed of dominantly greenschist-grade metasedimentary and metavolcanic rocks, and felsic to mafic plutons, of Neoproterozoic–Phanerozoic ages. The Hasanrobat granite in central SSB occurs as a single pluton, ~20km2 surface area, with relatively consistent mineralogy and chemistry. Quartz, alkali feldspars (microcline and perthite), sodic plagioclases and biotite are the main constituents, commonly associated with minor amphibole. Accessory phases include zircon, allanite, apatite, and magnetite. The country rocks are Upper Carboniferous–Lower Permian sandstones and dolomitic limestones. Scattered patches of skarn-type assemblages dominated by tremolite and talc occur in the dolomitic limestones, and sandstones are recrystallized to a coarse-grained quartzite at contact with the granite. The granite is metaluminous to slightly peraluminous, and is distinguished by high FeOt/MgO ratios, typical of ferroan (A-type) granites. The A-type affinity is also reflected by high Na2O+K2O, high Ga/Al ratios, high contents of large ion lithophile elements (LILE), high field strength elements (HFSE) and rare earth elements (REE), as well as low contents of Sr, and distinct negative Eu anomalies. The biotites are aluminous, Fe-rich, and plot near the siderophyllite corner in the quadrilateral biotite diagram. They are further distinguished by high fluorine contents (0.61 to 1.33wt.%). Amphibole is ferrohastingsite in composition. Ion microprobe analyses of zircon grains separated from a representative granite sample yielded concordant U–Pb ages with weighted mean 206Pb/238U age of 288.3±3.6Ma. The granite and the country rocks are cut by a set of mafic dykes with asthenosphere-like geochemical signatures. Such association suggests anorogenic intraplate magmatism in Lower Permian in the region. This provides further evidence for, and significantly constrains timing of, a major extension in Upper Paleozoic in Iran, previously inferred from the rock record. The extension led to the Gondwana break-up and the opening of Neotethys Ocean between Sanandaj–Sirjan and Zagros in Permian. [Copyright &y& Elsevier]