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Researches in Earth Sciences (20088299) (3)pp. 15-44
Introduction Fossil vertebrates were first reported from Iran by Priem (1908), who reported on the fossil fishes from the Pabdeh Formation east of Ilam, in southwestern Iran. At the time, Priem (1908) considered these deposits to be Lower Cretaceous, but they are now known to be Eocene (Afsari et al. 2014). Several decades later, fish material from the same deposits was studied by Arambourg (1967), who had attributed the beds to the Oligocene. Since those studies, additional fish from the Pabdeh Formation have been described or revised (e.g. Haghipour and Brants 1971; Jafarian et al. 1999; Afsari et al. 2014; Davesne 2017) including members of the Scombridae, Carangidae, and Labridae. These support the revised Eocene age of the sediments. Recently, Mirzaei et al. (2016) reported a Pycnodontiform (a Neopterygian bony fish) tooth plate from the Albian–Cenomanian Sarvak Formation at Lorestan, southwest Iran. To our knowledge, this is the only Cretaceous vertebrate fossil from Iran, excluding the material we report here. The objectives of this paper are to describe and interpret the vertebrate-bearing horizons of the Dariyan Formation in order to determine the age of the vertebrate-bearing beds and to provide a preliminary report on the vertebrate assemblage present in this locality.Materials and MethodThe Sivand Section is located 80 km northeast of Shiraz, on the eastern flank of the Sivand Anticline at E 52° 51´ 27.70´´ and N 30° 4´ 54.88´´. The Fahlian, Gadvan, Dariyan, Kazhdumi, and Sarvak formations are exposed in this area. The thickness of the Dariyan Formation in the Sivand Section locality is about 287 ms. Dariyan Formation is mainly composed of cherty limestone, radiolaria-bearing limestones, Hedbergella-bearing marls, and thin-bedded micritic limestone layers. Vertebrates and ammonites occur mainly in the lower part of the Dariyan Formation. Among the bioclasts, fragments of bivalves, gastropods, and ammonites, Orbitalina foraminifera, and marine vertebrate debris can be observed. A section of sixty-five meters of the lower deposits of the Dariyan Formation was measured in detail in this region.Result and Discussion The samples, mainly slabs of micritic limestone with vertebrate fossils were collected, wrapped, packed and safely transferred to the Department of Geology lab., at University of Isfahan. Extra samples were systematically obtained from the special horizons for thin sections also a few washing samples in order to determine the precise age of the fossil bearing horizons of the Lower Dariyan Formation. Slabs of the vertebrate fossils were cleaned by special pneumatic air pen tool, photographed and studied in details for anatomical characteristics. Based on the succession of microfossil assemblages (Choffatella decipiens Range Zone, Radiolaria flood Range Zone, Globiogerinelloides blowi Range Zone, Mesorbitolina parva Range Zone), we propose that the Sivand fossiliferous deposits are Early Aptian (Bedoulian) through early Late Aptian (Early Gargasian) in age. Fossil vertebrates are preserved in the lower part of the formation.ConclusionsLaboratorial studies, Microscopic characteristics and the thin sections led to discrimination of five orders of fish fossils (Aspidorhynchiformes, Clupeiformes, Ichthyectiformes, Pycnodontioformes, and Semionotiformes) and a marine turtle fossil of genus Toxochelys, accompanied with 9 genera and 14 species of foraminifera were identified that represents early Aptian (Bedoulian) to the beginning of late Aptian (Early Gargasian) ages for the studied parts of the Dariyan Formation in Sivand section. The Sivand locality preserves the first known Early Cretaceous assemblage of marine vertebrates from southwestern Asia. The obtained samples of marine vertebrates also introduced from other regions of the world, including North America, Europe, Australia, Africa, China and Lebanon. The preservation of a diverse assemblage of fossil vertebrates, makes the Sivand locality of special significance for understanding the diversity of vertebrates in lower Cretaceous of South Asia.
Researches in Earth Sciences (20088299) (2)pp. 29-52
Systematic investigation of vertebrate bearing horizons of Pabdeh Formation in Kuhrang area (Pole-Naal-Eshkanan, Kuhanak, Omid-Abad and Qanbar-Sini) leading to indentification of 8 families of Teleostis which includes: Fistularidae, Photichthyidae, Gempylidae, Myctophidae, Sternoptychidae, Gonostomatide, Clupeidae and Acanthuridae. Future to the fishes assemblages within the studied fauna 3 species of shrimp fossils were discriminated (Eopabdehus babaheydariensis, Eogordonella iranianiensis, Parsacus eocenicus). Based on the collected benthic and planctonic forminifers from the acid washing residues the Middle Eocene age can be assigned to the studied intervals.
Bulletin of Geosciences (12141119) 100(2)pp. 187-211
The Persian Gulf is the remains of an ancient seaway that connected the Indo–Pacific Region to the Mediterranean– Atlantic Region and the Paratethys Ocean. The Mishan Formation in Zagros Basin, Qeshm Island (Persian Gulf), and the Miocene strata of Minab Province in the Makran Basin, southern Iran, have yielded a rich fauna of bryozoans. A total of 22 species are here identified from four sections of in the Qeshm and Minab areas, including 13 species belonging to the order Cyclostomata, and 9 species belonging to the order Cheilostomata. The distribution and occurrences of the bryozoan fauna show the studied intervals were deposited during Early to Middle Miocene while the Iranian Seaways was connected to the Indo–Pacific Region from southeast, and to Mediterranean–Atlantic Region from northwest. Also, the most similar occurrences of the species described are with bryozoan faunas of the Paratethys Ocean. • Key words: Bryozoa, Miocene, Iran, taxonomy. © 2025, Czech Geological Survey. All rights reserved.
Boletin de la Sociedad Geologica Mexicana (14053322) 77(1)
The present study investigates the pectinid bivalve record characterizing the Mio-Pliocene of Mishan and Aghjari formations in Qeshm Island of the Persian Gulf and Minab region of Makran Basin (Hormozgan Province). Thick-bedded deposits of highly accumulated levels of epifaunal free-lying pectinids were investigated in terms of paleoecology and taphonomy. Eight species of the family Pectinidae (Bivalvia) and nine species of Ostracoda are reported from the Direstan rural area, Qeshm Island, Persian Gulf, Southern Iran. Most bivalve shells display extreme taphonomic features such as breakage, bioerosion, encrustation, disarticulation, and abrasion. Encrusting Cheilostomata bryozoans, as well as polycheata worms, encrust pectinid valves; Langian (Middle Miocene) Cheilostomata are identified as Microporella berningi. The studied pectinids are represented by the following species: Pecten aff. rotundatus, Pecten cf. subarcuatus, Flabellipecten piramidesensis, Argopecten gratus, Chlamys varia, Chlamys multistriata, C. actinodes, and Talochlamys articulata. Ostracoda were also collected from two more outcrops in Qeshm Island (Kendaloo and Star Valley) and one outcrop of Minab region (Bemani section). The studied ostracods are: Alocopocythere kendengensis, Actinocythereis iraqensis, Loxoconcha hamrinensis, Neomonoceratina iniqua, Bairdoppilata triangulata, Bairdia rafidainensis, Hermanites transversicoststs, Costa tricostata, and Cytherelloidea hamrinensis. © (2025), (Boletin de la Sociedad Geologica Mexicana). All rights reserved.
Rajabi A. ,
Mahmoodi P. ,
Alfonso P. ,
Canet C. ,
Andrew C. ,
Azhdari S. ,
Rezaei S. ,
Alaminia, Z. ,
Tamarzadeh S. ,
Yarmohammadi A. ,
Khan Mohammadi G. ,
Saeidi R. ,
Sattari, E. ,
Bahrami, A. ,
Vaziri moghaddam, H. ,
Taheri a., A. Minerals (2075163X) (7)pp. 1-25
Iran hosts more than 350 Precambrian to Cenozoic sediment-hosted Zn-Pb±Ba and barite-sulfide deposits, including shale-hosted massive sulfide (SHMS, also called SEDEX) and Irish-type and Mississippi Valley-type (MVT) mineralization, and barite is a common mineral in these deposits. In the SHMS deposits, barite is typically found as fine-grained disseminations in thin laminae. In these deposits, the sulfide laminae often occur as diagenetic replacements and as bands containing authigenic and diagenetic barite and pyrite framboids. In the Irish-type Zn-Pb-Ba and stratabound barite-sulfide deposits, barite exhibits various textures, including fine-grained disseminated barite, banded zebra textures, veins, and massive barite lenses. In some of the giant Irish-type deposits, as well as in the stratabound barite-sulfide mineralization, the main stratabound sulfide ore is developed within a barite envelope and is characterized by the replacement of barite and pyrite by chalcopyrite, galena, and sphalerite. In the MVT deposits, the formation of barite is often related to dolomitization, and sulfide mineralization involves the replacement of the dolomitized carbonate rocks, as well as associated barite. Fluid inclusion studies on the Irish-type deposits indicate that the temperatures and salinities of the sulfide-forming fluids are higher compared to those of the barite-forming fluids. Fluid inclusion analyses of coarse-grained barites from Irish and MVT deposits reveal their hydrothermal origin. The δ3⁴S values of sulfide minerals (pyrite, sphalerite, and galena) in Irish-type deposits exhibit a broad range of low values (mostly −28 to +5‰), primarily revealing a process of bacterial sulfate reduction (BSR). However, the textures (replacement, colloform, and banded) and more positive sulfur isotope values (+1 to +36‰) in the SHMS Zn-Pb deposits suggest that bacterial sulfate reduction (BSR) plays a less significant role. We suggest that thermochemical sulfate reduction (TSR) connected to the direct replacement of barite plays a more relevant role in providing sulfur for the sulfide mineralization in the SHMS, barite-sulfide, and MVT deposits. Based on the textual evidence, sulfur isotopic data, and fluid inclusion studies, barite has been identified as a key controller for the subsequent Zn-Pb mineralization by providing a suitable host and significant sulfur contribution in the sediment-hosted Zn-Pb and stratabound barite-sulfide deposits. This implies that diagenetic barite might be a precursor to all types of sediment-hosted Zn-Pb mineralization. © 2024 by the authors.
Boletin de la Sociedad Geologica Mexicana (14053322) 76(1)
The 1st order mass extinction at the Devonian/Carboniferous transition, known as the Hangenberg Crisis, is characterized by major transgressive/regressive cycles which led to widespread ocean anoxia during the Hangenberg Black Shale Event, as well as to a global major sea-level fall and the worldwide deposition of regressive Hangenberg Sandstone equivalents. The Devonian/Carboniferous transition at the Tuye-Darvar section in the eastern Alborz Range is studied in terms of conodont biostratigraphy, litho-, microfacies and sequence stratigraphy. In order to examine the biostratigraphical framework, forty conodont samples were systematically taken from the studied interval. Thirty-two conodont species belonging to ten genera led to the discrimination of twelve conodont zones, ranging from the Pseudopolygnathus granulosus Zone to the Scaliognathus anchoralis-Doliognathus latus Zone. Due to facies, the conodont record also exhibits some hiatuses. Field observations and sedimentological and microfacies studies led to the identification of thirteen facies types from sub-tidal environments to the fully marine environments, including seven microfacies types. The sediments deposited in a mixed carbonate-siliciclastic platform, revealed four third-order sequences. The Hangenberg Black Shale is not recorded in the Tuye-Darvar section as a result of depositional facies. In comparison with other studied Devonian/Carboniferous Boundary (DCB) sections of the central and northern Iran, the Tuye-Davar section suggests a tectonic position, which is most likely placed on a separate tectonic block. © (2024), (Boletin de la Sociedad Geologica Mexicana). All rights reserved.
Hadi, M. ,
Bahrami, A. ,
Less, G. ,
Consorti, L. ,
Parandavar, M. Micropaleontology (00262803) 70(2)pp. 171-196
A rich larger foraminifera assemblage from the Eocene carbonates of the south Sabzevar region (Now-Deh section) in central Iran indicates a late Ypresian to early Lutetian age. Nine species of Alveolina d’Orbigny are studied for systematics and biostratigraphy. The assemblage includes A. minuta, A. decastroi, A. cremae, A. cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata, A. frumentiformis. We have also found nummulitids (genus Nummulites and Assilina) and orthophragmines identified as N. campesinus, N. praediscorbinus, A. placentula, A. praespira, A. reicheli, A. ex. intrec. laxispira-maior and Discocyclina archiaci bartholomei. The recovery of Alveolina cremae elongata, A. decipiens ayrancensis, A. celali, A. rugosa, A. cuspidata and Assilina praespira has permitted for the first time to extend their geographical distribution outside of the classical peri-Mediterranean area to the central Tethys regions. The obtained biostratigraphy points to the Shallow Benthic Zones SBZ11 to SBZ13, indicating the occurrence of a Lower-–Middle Eocene carbonate system. Part of the age model is supported by the calcareous nannofossil biostratigraphy that belong to the NP14b and CNE8 biozones, recorded from the central portion of the studied section. Issues regarding the application of the SBZ into the Middle East domains are discussed in terms of relative stratigraphic position and biogeographic dispersal of some significant Alveolina species. © 2024, Micropaleontology Press. All rights reserved.
Sedghi, B. ,
Bahrami, A. ,
Veiga, I.M. ,
Dutheil, D. ,
Yazdi, M. Historical Biology (08912963)
Vertebrate remains are scarce in the Cretaceous of Iran, with only a few records of fishes and one genus of chelonioid turtle known from the Dariyan and Sarvak formations. Here, we describe for the first time the paleoichthyological fauna of the Kazhdumi Formation, based on disarticulated microremains that represent the first record of vertebrates in the unit, highlighting this novel Albian–Cenomanian fossil assemblage. The fauna is composed of lamniform (cf. Dallasiella sp., cf. Paranomotodon sp., Anacoracidae indet., cf. Haimirichia amonensis, cf. Scapanorhynchus, Lamniformes indet.) sharks and pycnodontiforms Osteichthyes. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Haskouei, F.M. ,
Bahrami, A. ,
Yazdi, M. ,
Moghaddam, H.V. ,
Bitner, M.A. ,
Vega, F.J. Journal of Stratigraphy and Sedimentology Researches (20087888) 40(4)pp. 41-62
The Late Miocene–Early Pliocene bivalve Placuna placenta (Linnaeus 1758) is reported for the first time from southern Iran. The shells of this species are extremely thin and fragile, and mostly disarticulated in our material, affected by compression, bioerosion, encrustation, and abrasion. In the Qeshm Island, midlate Miocene samples from Rahgostar were collected from marly deposits of the Guri Member of the Mishan Formation, Zagros basin. In the Minab region, samples from Bandzark were collected from MiocenePliocene sandstones of the Tiab Anticline in the Makran Basin. The studied species and their taphonomic features revealed tidal/intertidal shallow marine environment with high productivity, high rate of sedimentation, and rapid burial processes in low energy and high environmental stress, caused by strongly reduced salinity. Specimens of both assemblages affected by reworking processes, are represented by the following ichnospecies: Maeandropolydora sulcans, Oichnus simplex, and Trypanites weisei. © 2024 University of Isfahan.
Poursalehi, F. ,
Voldman, G.G. ,
Bahrami, A. ,
Mango, M.J. Palaeoworld (1871174X) 33(4)pp. 884-898
The Katkoyeh Formation comprises most of the Ordovician strata in the Kerman Province of East-Central Iran. However, determining its depositional timing remains challenging due to conflicting biostratigraphic ages, regional stratigraphic gaps, and tectonic complexities in the area. To enhance the understanding of the Katkoyeh Formation, a new conodont sampling was conducted at the Katkoyeh type section, which revealed 1,937 conodont elements belonging to 31 species of 26 genera. They allow the recognition of the Juanognathus variabilis Range Zone (middle–upper Floian) and the Icriodella superba Range Zone (Katian–?Hirnantian) in the Katkoyeh Formation, leading to better biostratigraphic and intercontinental correlations of the Ordovician strata in East-Central Iran with the Precordillera, the Famatina System, and the Central Andean Basin of northwestern Argentina, as well as with North American Midcontinent and North Atlantic basins, and South China. Moreover, the oral structure of Juanognathus variabilis Serpagli is reassessed based on the new Iranian records, recognizing 7 morphotypes in its apparatus structure, referred to the M, Pa, Pb, Sa, Sba, Sbb and Sc positions. © 2023 Elsevier B.V.
Hadi, M. ,
Consorti, L. ,
Bahrami, A. ,
Parandavar, M. ,
Khorramdel, S. Journal of Palaeogeography (20953836) 13(1)pp. 54-79
Precise taxonomy and the chronostratigraphic calibration of the Middle Eocene Alveolina from Central Iran is here undertaken from the Chah-Talkh section of the southern Sabzevar region (Central Iran). We have identified Alveolina kieli, Alveolina stercusmuris and Alveolina nuttalli along with the new species Alveolina ozcani n. sp. that we include into the Alveolina elliptica group. We have also found Nummulites uroniensis, Nummulites obesus and Nummulites cf. verneuili and associated calcareous nannofossils that look reliable to make thoughtful correlations with the Shallow Benthic Zones (SBZ). The foraminiferal biostratigraphy suggests an assignment to the upper part of the lower Lutetian–lower part of the middle Lutetian, SBZ13 (Middle Eocene), further strengthened through the identification of the calcareous nannofossil NP14b–NP15b or CNE8–CNE10 biozones, providing a solid correlation with the global stratigraphic standards. © 2023 The Author(s)
Journal of Economic Geology (20087306) 16(2)pp. 95-134
In the western boundary region of Central Iran with Sanandaj-Sirjan, considering the widespread carbonate units in the northeastern Isfahan area, the barite deposits have considerable potential. The Komsheche barite, hosted in the Middle Triassic Shotori dolomite Formation, is the most active mine in the region. Barite mineralization has occurred in two styles, banded-layered and veined-brecciated. Fluid inclusions in the bedded barite homogenize at temperatures from 78 to 122 ºC, with salinity between 10.9 to 17.0 wt.% eq. NaCl, while the homogenization temperature for two-phase inclusions of the second type barite is between 130 to 187 ºC and associated halite-bearing tri-phase inclusions range from 192 to 210 ºC, with an average salinity of 14.3 and 36.6 wt.% eq. NaCl, respectively. The δ34S values of the samples range from 18.40 to 26.34 per mil CDT, and their δ18O values range from 8.9 to 14.7 per mil SMOW. Based on conducted studies, ore-forming fluids were formed in an open and near-bottom seawater system during the early diagenetic stage. The heavy isotope values related to pore water are locked in a closed system during the final stages of diagenetic. Sedimentary type, associated minerals, REE composition, finding of fluid inclusion and isotope reveal that Komsheche barite has the most similarity to diagenetic/cold-seep types of marine barites. © 2024 The author(s).
Acta Geologica Sinica (English Edition) (17556724) 97(4)pp. 1038-1057
The Late Devonian–early Carboniferous deposits of the Anarak section in northeastern Isfahan, Central Iran, evaluated based on conodont biostratigraphy, sedimentary environment and sequence stratigraphy. According to the field observations, five lithological units were identified. Investigating the conodont fauna of the Late Devonian–Carboniferous (Mississippian–Pennsylvanian) deposits of Bahram, Shishtu, and Qaleh (Sardar 1) formations in Anarak section led to the identification of 67 species of 18 conodont genera, and accordingly 22 conodont biozones were differentiated. The correlation of sea-level change curves, regarding to the conodont biofacies with the global sea-level curve, demonstrates the relative correlation in the mentioned times due to the shallow condition of the central Iran basin compared to the European and American basins. The microfacies analysis led to the identification of 12 microfacies related to the open sea, bioclastic barrier, lagoon and tidal flat sub-sedimentary environments in a homoclinal carbonate ramp environment. Based on sequence stratigraphy studies, three 3rd order sequences were identified. The first sequence, which is of the Late Devonian (upper part of the Bahram Formation, 32.5 m), the second sequence (12.5 m) is the Late Devonian (uppermost part of the Bahram Formation), and the third sequence (68 m) is the early Carboniferous (the Shishtu I Formation). © 2023 Geological Society of China.
Annales Societatis Geologorum Poloniae (02089068) 93(4)pp. 411-422
The study presents the first record of Early Oligocene brachiopods from the Lower Red Formation of the Isfahan Province, Central Iran. The assemblage comprises six brachiopod taxa, belonging to five genera, Novocrania Lee and Brunton, Thecidellina Thomson, Argyrotheca Dall, Joania Álvarez, Brunton and Long, and Platidia Costa. Two species are described as new, Thecidellina persica sp. nov. and Argyrotheca ramshehensis sp. nov. The discovery of Thecidellina in Iran is the first confirmed occurrence of this genus in Oligocene deposits, filling the gap between known Eocene and Miocene occurrences. At the species level, the brachiopods investigated here show no affinity to those from the Lower Miocene Qom Formation. © 2023, Polish Geological Society. All rights reserved.
Boletin de la Sociedad Geologica Mexicana (14053322) 75(3)
The Albian-Cenomanian deposits of the Kazhdumi Formation at Zagros Basin (Firuzabad section and Central Iran (Fasakhod section), represents a carbonate sedimentary succession and contain rich and diverse invertebrate macro fauna. Detailed studies on about 200 specimens of invertebrate macro fauna revealed from two stratigraphic intervals led to recognition of 5 species of gastropods; (Liopeplum? sp., Columbellina sp., Cryptaulax? sp., Turritella? sp., Pleurotomaria sp.), 3 species of ammonites; (Knemiceras duberterti, Sphenodiscus sp., Knemiceras persicum), 10 species of bivalves assemblages; (Ceratostreon flabellatum, Cardium? sp., Exogyra (Costagyra) olisiponensis, Neithea (Neithea) quinquecostata, Trigonia sp., Buchia? sp., Cardium? sp., Pseudogyra sp., Ontaria? sp., Nucula? sp., Pleuromia? sp., 1 species of echinoids; Dorocidaris taouzensis with a prolific horizon of Notopocorystes xizangensis of raninoid crabs. The absence of large gastropods and bivalves fauna and abundance of suspension-feeders indicated instability of the substrate, shallow marine paleoenvironment. and a medium energy condition. © (2023). All Rights Reserved.
Bitner, M.A. ,
Bahrami, A. ,
Josheghani, M.S. ,
Yazdi, M. ,
Zágoršek, K. Boletin de la Sociedad Geologica Mexicana (14053322) 75(2)
The study presents new records of brachiopods from the Lower Miocene deposits of the Qom Formation from two sections, Bagh and Ramsheh in the Isfahan province, Central Iran. Three species, i.e. Argyrotheca bitnerae, Joania cordata, and Platidia anomioides, have been identified in the investigated material. All species are present in the Bagh section whereas in the material from Ramsheh A. bitnerae was not found. Although the species recognized here were already described from the Miocene of the Qom Formation, this is their first report from the localities of Bagh and Ramsheh, providing new data on the distribution of brachiopods in the Cenozoic of Iran. © This is an open access article under the CC BY-NC-SA license (https://creativecommons.org/licenses/by-nc-sa/4.0/)
Acta Geologica Polonica (00015709) 73(2)pp. 189-200
New findings of crustacean decapod brachyurans from the Rupelian period (lower Oligocene) in Iran are presented in this study. In particular, Lophoranina sp. and Palaeocarpilius cf. P. rugifer Stoliczka, 1871, from the Rupelian strata were found in two previously unexplored localities, Abshar and Vezg near Yasuj in the southwestern region of Iran. The discovery contributes to fill the gap in the record of brachyuran decapod crustaceans in Iran during the Eocene and Miocene periods. The presence of both genera in the Oligocene of Iran suggests a certain degree of faunal similarity among brachyurans on both sides of the Tethys Realm. © 2023 Polish Academy of Sciences. All rights reserved.
Annales de Paleontologie (07533969) 109(1)
In the present work, we report the discovery of several carapaces of Zanthopsis sp. from the Lower Eocene of Central Iran, which represent the easternmost record of the genus. In addition, we discuss on the similarities of the different species and/or morphotypes of the genus, and conclude that the European species could be ascribed to the “Zanthopsis leachii complex”, until future works determine the validity of the species therein contained. In this sense, Zanthopsis jacobi Van Straelen, 1924, in agreement with Artal and Vía (1988), is herein considered a junior synonymous of Z. dufouri (H. Milne Edwards in d'Archiac, 1850). The presence of Zanthopsis in the lower Eocene of Iran suggests homogeneity of the brachyuran fauna on both sides of the Tethys Realm. © 2023 Elsevier Masson SAS
Researches in Earth Sciences (20088299) 13(3)pp. 1-25
Introduction Close to the DCB, Hangenberg Event have occurred, due to rising global temperatures, evidence of sea level rise, eutrophic conditions, anoxic conditions, rising carbon burial, formation of the Hangenberg Black Shale, and depletion of shallow and especially deep marine fauna in deposits (De Vleeschouwer et al, 2013). The Jeirud Formation in its type section (consists of sandstone, brachiopod-bearing dark shales, and phosphate horizons) diconformably covers the Mila Formation, and is continously underlain by the Mobarak Formation (Bozorgnia, 1973). Materials and methods The Tuye-Darvar section location The Tuye-Darvar section is located Eastern Alborz Zone, adjacent to Darvar village (southwest of Damghan city) with base of the section: 36° 01' 27.31" N, 53° 53' 17.33" E; top of the section:36° 01' 19.32" N, 53° 53' 33.03" E. Method of study After detailed field studies, 44 rock samples were collected to study the conodont fauna based on standard methods (Jeppson and Anehus, 1995). After sediment dissolution, washing and hand picking under binocular microscope, stub preparation and gluing conodonts on aluminum base, determining the color alternation index of conodonts with the help of standard tables, preparing SEM photos, naming and identifying conodonts and their biozones was performed based on global refrences (Sandberg et al, 1978; Ziegler et al, 1990; Hartenfels, 2011; Corradini et al, 2016; Spalletta et al, 2017). Results and discussion Lithostratigraphy Jeirud Formation: The thickness of the Jeirud Formation in this section is 166 m, and includes the lower siliciclastic part with a thickness of 84 m and consists of 3 Lithostratigraphy units (included sandstone, conglomerate and shale) and the upper carbonate-siliciclastic part with a thickness of 82 m and consists of 3 Lithostratigraphy units (included sandstone, dolomites, microconglomerate, shale and limestone). Mobarak Formation: The Mobarak Formation disconformably covers the Jeirud Formation, with thickness 81.5 m thickness and underlies the vermiculite limestones of the Elika Formation (Triassic) through a fault surface. Based on the lithological characteristics, three stratigraphic units can be distinguished in this interval (including dark limestone and shale). Conodont biostratigraphy Study on the conodonts in the mentioned section led to the discrimination 32 species within 10 genera: Bispathodus, Branmehla, Clydagnathus, Gnathodus, Polygnathus, Pseudopolygnathus, Palmatolepis, Protognathodus, Scaphygnathus, Siphonodella According to the age range of conodont species, 12 conodont zonation were identified, of which 9 biozones belong to the Late Devonian (Late Famennian) and 3 biozones belong to the Early Carboniferous (Mississippian). The Late Devonian biozones included: 1. Pseudopolygnathus granulosus Zone, 2. Polygnathus styriacus Zone, 3. Palmatolepis gracilis manca Zone, 4. Palmatolepis gracilis expansa Zone, 5. Bispathodus aculeatus aculeatus Zone, 6. Bispathodus costatus Zone, 7. Bispathodus ultimus Zone, 8. Siphonodella praesulcata Zone to ckI Zone, 9. Protognathodus kockeli Zone And the Late Carboniferous included: 10. Siphonodella sulcata Zone – L. Siphonodella crenulata Zone, 11. Siphonodella isosticha-U. Siphonodella crenulata Zone – Gnathodus typicus Zone, 12. Scalignathus anchoralis-Doliognathus latus Zone Sea level changes and the paleoenvironment of the Tuye-Darvar section With combination of the 2 biofacies models to the Late Devonian deposits according to Sandberg and Dreseen (1984) studies and to the Early Carboniferous deposits according to Sandberg and Gutschick (1984) studies, conodont biofacies in the studied section was studied in the Late Devonian and the Early Carboniferous, that according to that, dominant biofacies in Late Devonian included (Polygnathid, Pseudopolygnathid, Bispathodid and Bispathodid-polygnathid) and dominant biofacies in the Early Carboniferous included (Bispathodid-polygnathid, Polygnathid, Pseudopolygnathid, Gnathodid and Gnathodid- pseudopolygnathid). Conclusion The lithostratigraphy study of the Tuye-Darvar section in Eastern Alborz Zone due to identified 9 lithostratigraphy unit belong to Jeirud Formation with the Late Devonian period and the Mobarak Formation with the Early Carboniferous period. 32 number of species within 10 genera were recognize, that base on this, 12 biozones in the Late Devonian and Early Carboniferous were separated. With study of biofacieces, in the Late Devonian and the Early Carboniferous, that according to that, dominant biofacies in Late Devonian included (Polygnathid, Pseudopolygnathid, Bispathodid and Bispathodid-polygnathid) and dominant biofacies in the Early Carboniferous included (Bispathodid-polygnathid, Polygnathid, Pseudopolygnathid, Gnathodid and Gnathodid- pseudopolygnathid). © 2021, Shahid Beheshti University. All rights reserved.
Palaeoworld (1871174X) 31(1)pp. 69-85
The Devonian/Carboniferous (D/C) transition is characterized by a major transgressive/regressive cycle which led to a widespread ocean anoxia known as the Hangenberg Black Shale Event (HBSE), as well to a major sea-level fall (Hangenberg Sandstone Event, HSSE), recognized around the world. Both events are known as the Hangenberg Crisis. In order to examine the D/C transition in shallow water environment, the Mighan section in eastern Alborz was studied in terms of conodont biostratigraphy and stable isotope geochemistry. Twenty-five conodont species belonging to seven genera were identified and 5 conodont zones discriminated; namely, the Bispathodus aculeatus aculeatus Zone, Bispathodus costatus Zone, Bispathodus ultimus Zone, Siphonodella praesulcata Zone, costatus-kockeli Interregnum, and the sulcata Zone. Below the Devonian–Carboniferous boundary (DCB), the Hangenberg Black Shale and Hangenberg Sandstone equivalents were recognized, representing the Hangenberg Crisis that highly affected trilobite, ammonoid, brachiopod and conodont faunas at Mighan and worldwide. The kockeli Zone of the latest Famennian is missing at Mighan due to the lack of conodonts, probably related with the major environmental changes linked with the Hangenberg Crisis recognizable worldwide. Carbon isotopes measured of micrites from Mighan indicate a proximal depositional environment of a shallow shelf with terrestrial input and the oxygen isotope values from conodont apatite suggest warm seawater temperatures of tropical and subtropical setting in the study area. © 2021
Carbonates and Evaporites (08912556) 37(3)
The presence of trace fossils and their diversity in Miocene deposits of western Makran accretionary prism (SE Iran) was the center of this research. The trace fossil contents of Cheraghsuz and Sardasht (with Middle Miocene in age) and Gowharan (with Early Miocene in age) stratigraphic sections were analyzed. The recognized specimens of the Cheraghsuz section are Gordia isp., Helminthopsis hieroglyphica, Helminthopsis abeli, Helminthorhapheflexsuosa, Paleodictyon maximum, and Spirorhaphe involuta. The Sardasht section is composed of Gordia isp., Helminthopsis hieroglyphica, Helminthopsis abeli, Helminthorhapheflexsuosa, Paleodictyon maximum, Paleodictyon majus, Paleodictyon isp., Spirorhaphe involuta, Helicolithus isp., Helicorhaphe tortilis, and Neonereites isp. In the Gowharan section, some gastropod trails, a giant and very well-preserved Archaeonassa-like ichnogenus, and ripple marks were observed. Majority of the recognized trace fossils are of the graphoglyptid group. The trace fossil contents of Cheraghsuz and Sardasht sections are compatible with Nereites ichnofacies; as graphoglyptids are thought to be indicative of oligotrophic conditions, the trace-producers are filter-feeder organisms that normally tend to take suspended nutrient materials in the water column, but due to lower sedimentation rate, the nutrient content is concentrated on the superficial part of the substrate; accordingly, the trace-makers prefer grazing and moving on the surface sediment to take their food. However, the exceptionally preserved trace fossils in Gowharan section should be formed in a tidal flat environment. In relation to the floor, it has recorded at least three shapes, including bi-lobed, uni-lobed and submerged forms. In addition, it could be observed that different trace fossils may be created by a single animal and different animals may create the same trace fossils. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Bahrami, A. ,
Königshof, P. ,
Hartkopf-fröder, C. ,
Kaiser, S.I. Palaontologische Zeitschrift (18676812) 96(3)pp. 449-469
Devonian/Carboniferous conodonts from the Chelcheli section in the Alborz Mountains were investigated. Although conodonts are generally less abundant in the entire section, important zonal index taxa of the widely applied conodont standard zonation could be used for a precise conodont zonation. Forty-seven conodont species belonging to fifteen genera were identified and led to the discrimination of fifteen conodont zones, ranging from the Palmatolepis minuta minuta Zone into the Scaliognathus anchoralis-Doliognathus latus Zone. At the Devonian/Carboniferous boundary (DCB), characteristic lithologies such as black shales and massive sandstones represent equivalents of the Hangenberg Black Shale and Hangenberg Sandstone. Close to the DCB, there is a small stratigraphic hiatus in the conodont record which might be a result of facies (shallow-water succession with no conodont record and siliciclastic rocks) rather than a period of non-deposition as the sedimentological record seems continuous. Similar to other DCB sections in shallow-water facies in Iran the two biostratigraphically important species Protognathodus kockeli and Protognathodus kuehni do not occur. © 2021, Paläontologische Gesellschaft.
Poursalehi, F. ,
Voldman, G.G. ,
Bahrami, A. ,
Salas, M.J. ,
Ameri, H. Bulletin of Geosciences (12141119) 97(3)pp. 363-384
Ordovician marine sedimentary sequences occur in several widely separated structural blocks in Iran, along the northern margin of Gondwana. In northern Kerman Province, the Ordovician sedimentary interval is known as the Katkoyeh Formation, which encompasses ~ 70–300 m of siliciclastic rocks with scarce carbonate and thick pyroclastic beds in its upper part. Previous studies provided several ages for the Katkoyeh Formation, puzzled by the limited number of palaeontological studies, mostly based on spot samples, the presence of regional important stratigraphic gaps, and the inherent structural complexity of the area. In order to adjust the depositional time of the Katkoyeh Formation, a systematic sampling for microfossils was conducted in the Banestan Section, located about 12 km northwest of the city of Zarand, in the vicinity of the Banestan village. Based on the occurrence of important biostratigraphic species, we recorded three conodont intervals in ascending order in the Katkoyeh Formation, namely the Rossodus manitouensis/ Paltodus deltifer Concurrent Range Zone (Tremadocian, Lower Ordovician), the Juanognathus variabilis Range Zone (Floian, Lower Ordovician), and the Icriodella superba Range Zone (Katian–?Hirnantian, Upper Ordovician). The conodont biostratigraphy is discussed and analysed, improving the Ordovician intrabasinal correlation of Iran as well as correlation with distant palaeobiogeographic domains. The Upper Ordovician conodont assemblage is accompanied by two new species of ostracods: Satiellina zarandensis sp. nov. and Ceratopsis persicus sp. nov., both suggesting palaeobiogeographical affinities mainly with Gondwana and peri-Gondwanan regions. © 2022, Czech Geological Survey. All rights reserved.
Boletin de la Sociedad Geologica Mexicana (14053322) 73(3)
From the lower Miocene (Burdigalian) of the Qom Formation, exposed in threesections (Kuh-e-Donbeh, Bagher-Abad,and Vartun) in Central Iran, a decapodcrustacean assemblage is described. Thespecimens exhibit two modes of preservation:carapaces (either isolated orwith attached appendages) and isolatedcheliped elements. All studied specimensare fractured and/or eroded. Based onthis moderately preserved material, threebrachyuran crab taxa are identified,including Mursia cf. lienharti (Bachmayer,1962), Palaeocarpilius rugifer Stoliczka, 1871,and Necronectes sp. The occurrence of P.rugifer represents the youngest confirmedoccurrence of the species, whereas othertwo taxa represent the first confirmedIranian occurrences of respective genera.This report enriches our knowledge onMiocene decapod assemblages of Iran,and thus helping to better understandthe decapod migratory patterns along theTethyan Seaway © 2021. Boletín de la Sociedad Geológica Mexicana. All Rights Reserved.
Palaeobiodiversity and Palaeoenvironments (18671608) 101(2)pp. 613-632
Many sections are known from Iran which exhibit sediments across the Devonian-Carboniferous (D-C) boundary. In contrast to the majority of published D-C sections worldwide from pelagic/hemipelagic environments, successions in Iran are mainly composed of shallow-water sediments. Correlation with hemipelagic or pelagic palaeoenvironments remains difficult due to biostratigraphic uncertainties in most sections and/or hiatuses. On the other hand, a limited number of sections dealing with shallow-water facies settings in Iran at this particular time period are known and further research is necessary. Several sections in the Alborz Mountains provide an excellent opportunity to study successions across the D-C boundary in shallow-water facies. In Iran, protognathoids are represented by Protognathodus meischneri and Protognathodus collinsoni. The two biostratigraphically important protognathoids (Protognathodus kuehni and Protognathodus kockeli) were not reported or did not occur for the first time in the Late Tournaisian. Early siphonodellids were described instead. In the frame of an Iranian/German research project, we study different palaeoenvironments to reduce serious palaeoenvironmental and palaeogeographical sampling bias which may limit our knowledge on the Hangenberg Event particularly in shallow-water facies. We present a summary on published D-C sections in Iran (Ghale-Kalaghu, Howz-e-Dorah 1, Howz-e-Dorah 2 and Shahmirzad) and sections which are under study (Mighan, Chelcheli and Khoshyeilagh) at the time of this writing. © 2020, The Author(s).
Bahrami, A. ,
Yazdi, M. ,
Moghaddam, H.V. ,
Ghobadi, A. ,
Murray, A.M. ,
Brinkman, D. ,
Shirazi, M.P. ,
Mirzaie ataabadi, M. ,
Kundrát, M. Historical Biology (08912963) 33(3)pp. 387-402
The Mesozoic fauna of southwestern Asia remains poorly understood. Here, we report on an assemblage of marine invertebrates and vertebrates from the Lower Cretaceous Dariyan Formation of Iran. The Dariyan Formation consists of 60 m of carbonates deposited in shallow seas. These deposits exhibit a high abundance of foraminifera that belong to nine genera and 14 species. Based on the succession of microfossil assemblages (Choffatella decipiens Range Zone, Radiolaria flood Range Zone, Globiogerinelloides blowi Range Zone, Mesorbitolina parva Range Zone), we propose that the Sivand fossiliferous deposits are Early Aptian (Bedoulian) through early Late Aptian (Early Gargasian) in age. Fossil vertebrates are preserved in the lower part of the formation. A diverse assemblage of fishes is present, including Aspidorhynchiformes, Ichthyodectiformes, Pycnodontiformes, Aulopiformes, and Clupeomorpha, and one genus of chelonioid turtle that is either a member of the Protostegidae or Dermochelyidae. The similarities in the fish assemblages of the Dariyan Formation of Iran with the Santana Formation of Brazil and the Tlayúa Quarry in south-central Mexico show that these fishes were distributed throughout the equatorial region and were widely spread in the shallow seaways of the Early Cretaceous. © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Palaeobiodiversity and Palaeoenvironments (18671608) 101(3)pp. 781-802
A relatively complete conodont record from Famennian to the Mississippian/Pennsylvanian boundary was investigated in the Anarak section, Central Iran. The studied interval belongs to the Bahram, Shishtu, Ghaleh and Absheni formations. The Famennian part of the section (Bahram Formation) ranges from the Palmatolepis triangularis Zone into the Bispathodus ultimus Zone. Not all conodont zones could be defined due to the lack of indicative species. Furthermore, it seems likely that a hiatus occurs around the Devonian/Carboniferous (D/C) boundary (most probably from the Siphonodella praesulcata to the ?Siphonodella sulcata–early Siphonodella crenulata conodont zones) based on the lack of stratigraphically important conodonts as well as on sedimentological criteria. The lack of representative siphonodellids and protognathodids at the base of the Mississippian prevents detailed stratigraphic position of the D/C boundary. Lower Carboniferous (Mississippian) rocks are characterized by red nodular limestone which is unique in comparison with other studied sections of the same age in Central Iran. Within the studied section, we could define the Mississippian/Pennsylvanian boundary. The mid-Carboniferous boundary was defined by the occurrence of Declinognathus noduliferus s.l. Conodont biofacies changes (Mississippian genera Gnathodus and Lochriea have been replaced by Pennsylvanian genera Declinognathus and Idiognathodus) are recognized in this section as well. © 2021, The Author(s).
Zamani, F. ,
Yazdi, M. ,
Bahrami, A. ,
Girard, C. ,
Spalletta, C. ,
Ameri, H. Historical Biology (08912963) 33(11)pp. 2591-2609
The Givetian to Famennian (Middle-Upper Devonian) Bahram Formation deposits (Bondar and Shahzadeh Mohammad sections) in the Kerman region, Central Iran were sampled for conodonts. The conodonts were described, their distribution investigated, and the studied sections were correlated. In the previous conodont-based papers, the age of the Bahram Formation in the Kerman region was from the upper Givetian hermanni Zone to the middle Famennian Uppermost marginifera Zone (Middle to Late Devonian). However, the new results of this study show that the Bondar section spans from the middle Givetian ansatus Zone to the upper Famennian (middle part of the Middle expansa Zone = Bispathodus aculeatus aculeatus Zone) and the Shahzadeh Mohammad section spans from the middle Givetian ansatus Zone to the lower Famennian (Uppermost crepida = Palmatolepis glabra pectinata) Zone. In both of the studied sections, the Givetian/Frasnian boundary has been identified by the first occurrence of Ancyrodella rotundiloba pristina, but there is no obvious (sedimentological or biostratigraphic) evidence to define the Frasnian/Famennian boundary. © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Najjarzadeh, M.T. ,
Ashouri, A.R. ,
Yazdi, M. ,
Bahrami, A. Iranian Journal Of Earth Sciences (2228785X) 12(2)pp. 98-123
Devonian-Carboniferous boundary is not clear in the Eastern Alborz Mountains. In the current study Tuyeh-Darvar section with about 170 m, thickness is selected. In this investigation, the primary goal is revision of Devonian/Carboniferous Boundary (known as DCB) and the other goal is the redefinition of the DCB as a famous necessity (based on ICS program in 2008 for defining the boundary and to find a new GSSP). According to Conodont data from acid-leaching 53 carbonate samples(by acid acetic) that obtained from Late Devonian and Early Carboniferous deposits in this section, and based on standard conodont Zonation 6 Zone are recognized; 1. Bi. ultimus/or Si. praesulcata Zone, 2. Pr. kockeli /or Si. sulcata Zone, 3. Si. duplicata to Si. sandbergi bio interval, 4. Si. crenulata Zone, 5. Gnathodus-P. inornatus Zone, and 6. Ps. multistriatus Zone. Considering to the Conodont Zones above mentioned, Conodont faunas and other evidences, in the Tuyeh-Darvare section the DCB, is located within cream to grey silt stone beds, which are lies between K6 limestone and K8 dark carbonate beds (about 7.10 m above the base of recent studied section). © 2020 Islamic Azad University.
Bahrami, A. ,
Yazdi, M. ,
González-león, O. ,
De lourdes serrano-sánchez, M. ,
Vega, F.J. Boletin de la Sociedad Geologica Mexicana (14053322) 72(2)pp. 1-14
The second fossil isopod from Iran is herein reported. Additional specimens of the small lobster Huhatanka iranica Bahrami and Vega in Yazdi et al. (2010) are also revised. The aforementioned allows differentiating this species from the only other known species, H. kiowana (Scott, 1970) from the Albian of Kansas, USA. Some indeterminate callianassoids, found associated with the isopod and H. iranica, are also reported. © 2020 Instituto de Geolog+?-?a, Universidad Nacional Aut+?-?noma de M+?-?xico.
Palaeobiodiversity and Palaeoenvironments (18671608) 100(3)pp. 705-718
A bryozoan fauna from the Upper Devonian (lower Famennian) of the Bahram Formation of the Baqer-abad section in central Iran contains four species: three trepostomes and one rhabdomesine cryptostome. Two trepostome species and one genus are new: Anomalotoechus parvus sp. nov. and Zefrehopora asynithis gen. nov. et sp. nov. The trepostome Coeloclemis zefrehensis Ernst et al., 2017 and the rhabdomesine cryptostome Euthyrhombopora tenuis Ernst et al., 2017 were recorded previously from the Upper Devonian (Frasnian) of the Bahram Formation at the Zefreh section. The fauna is dominated by the erect ramose Euthyrhombopora tenuis, accompanied by relatively frequent Zefrehopora asynithis, which developed both the erect and encrusting colonies. The bryozoans indicate low to moderate water energy environment in a middle to outer ramp position. Low diversity and high abundance of one species indicate an environmental stress apparently caused by strong sediment deposition. No significant differences in the composition of the bryozoan assemblages of the Frasnian and lower Famennian of the Bahram Formation were observed mirroring global patterns. © 2020, The Author(s).
Boletin de la Sociedad Geologica Mexicana (14053322) 72(2)pp. 1-19
Isfahan Province, Central Iran has a thickness of 220 m representing mainly shallow-water palaeoenvironments with fossiliferous abundance and biodiversity. The zonal division in this section includes ten Famennian zones as follows, from the bottom to the top: triangularis Zone, crepida Zone, Lower rhomboidea Zone, gracilis-Lower marginifera interval Zone, Upper marginifera barren Zone, Uppermost marginifera-trachytera interval Zone, postera Zone, Lower expansa Zone, Middle expansa Zone, Upper expansa-praesulcata interval Zone. This section comprises the most complete biozonation of the Famennian stage in the area of northeast Isfahan in Central Iran. The analysis of the conodont associations and biofacies support the interpretation that these shallow-water habitats were still in platform conditions. Based on the conodont record, major stratigraphic gaps also occur at the end of Famennian, which confirms earlier results reported from other sections with similar palaeoenvironments in the North Isfahan area. © 2020 Instituto de Geolog+?-?a, Universidad Nacional Aut+?-?noma de M+?-?xico.
Salehi, M.A. ,
Bahrami, A. ,
Moharrami, S. ,
Vaziri moghaddam, H. ,
Pakzad, H.R. ,
Shakeri, B. Journal of African Earth Sciences (1464343X) 171
The predominantly warm greenhouse climate and high global sea level during the Middle–Late Devonian resulted in fully marine conditions along the northern Gondwana margin, including the Iranian Plate. Over three-hundred meter-thick fossiliferous Middle-to Late Devonian carbonate deposits of the Bahram Formation in the Anarak region (western Central Iran) are composed of dark grey limestone, dolostone, and interbedded shale. Seventeen microfacies have been distinguished, which correspond to four depositional sub-environments, i.e., tidal flat, lagoon, shoal, and open marine. The Middle–Late Devonian carbonate deposits were deposited on a homoclinal carbonate ramp. Seven third-order depositional sequences are identified, apparently controlled by relative sea level change. Carbon and oxygen stable isotopes, and major and trace elements of micritic carbonate samples document details about the geochemical, palaeoenvironmental, and diagenetic processes; they also indicate that the carbonates underwent meteoric diagenesis within a semi-closed diagenetic system. The low concentrations of trace elements indicative of euxinic conditions, including Mo, Cr, V, and As, suggest well-oxygenated depositional environment. Carbon isotope values show a meaningful relationship to major sequence-stratigraphic key surfaces, with more negative values occurring at the sequence boundaries and positive values corresponding to maximum flooding surfaces. © 2020 Elsevier Ltd
A comprehensive study of the palaeoenvironmental and post-mortem conditions of Cenozoic clypeasteroids from the Miocene (Aquitanian) of the Qom Formation in the Esfahan–Sirjan Basin (central Iran) is based on test morphology, taphonomy, test surface preservation, echinoid abundance and echinoid sedimentary fabrics (density, orientation, and cluster), and facies analysis. The deposit-feeding clypeasteroids lived in deeper open-marine, shallow open-marine and shoal settings in a sublittoral environment. The low–moderate energy, deeper open-marine facies contain the lowest population of clypeasteroids, including rare shallow infaunal Parascutella and rare semi-infaunal Clypeaster. The moderate to high energy shallow open-marine facies contains the highest abundance and diversity of Clypeaster. The shallow open-marine and high-energy shoal facies are dominated by epibenthic Clypeaster individuals with robust, inflated and commonly dome-shaped tests. Differences in the abundance and diversity of the living clypeasteroids were related to water depth, food sources and energy levels. Different food sources, life-styles and burrowing depths are indicated by the particular morphologies of the echinoids. Dead echinoids, especially the robust and inflated Clypeaster individuals, were used as substrates and domiciles by skeletozoans and other epibiontic organisms. Disarticulation, fragmentation, bioerosion, test outline distortion and radial cracking affected the preservation of the dead clypeasteroid tests. The clypeasteroid shells in the deposits accumulated as 1—an almost autochthonous assemblage (Parascutella), 2—a moderately transported and reworked assemblage (Clypeaster and Parascutella) and 3—transported and multiple reworked assemblages (Clypeaster) affected by storms. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Historical Biology (08912963) 31(5)pp. 574-580
Fossil insects are very rarely found in sediments of deep marine origin. Nevertheless they can be of great interest to trace past events such as trans-oceanic migrations. Here we document the first fossil insects from Iran, viz. several alate ants dead during mating swarms and a migratory locust, found in the pelagic Oligocene sediments of the Zagros Mountains. This locust represents the first putative indication of insect migrations between the Arabian-African and Asiatic continents through the Parathetys, probably in relation with the development of open grassland biotas in these areas. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.
Pedramara, A. ,
Zágoršek, K. ,
Bitner, M.A. ,
Yazdi, M. ,
Bahrami, A. ,
Maleki, Z. Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 294(2)pp. 229-250
A study of bryozoans and brachiopods from the Varton, Zefreh and Kuh-e-Charkheh sections from the Esfahan-Sirjan fore-arc basin of the Qom Formation of Central Iran has yielded 30 bryozoan taxa, including one new species Gigantopora vartonensis, and six brachiopod species. Both assemblages co-occur with large oyster shells with some of the ventral valves of brachiopods directly attached to their shells. The paleoenvironment is interpreted as an oyster bank (‘oyster reef’) in shallow, tropical-subtropical marine waters, producing cryptic habitats for other groups of organisms. © 2019 E. Schweizerbart'sche Verlagsbuchhandlung.
Palaeobiodiversity and Palaeoenvironments (18671608) 99(3)pp. 477-494
The Middle to Upper Devonian Kuh-e-Bande-Abdol-Hossein section in eastern Central Iran is an overall shallow marine, nearshore to open marine facies setting that contains a highly variable conodont record generally characterised by an Icriodid-Polygnathid biofacies. The lithology and the palaeoenvironmental setting is similar to other localities in Central Iran and exhibits numerous hiatuses. A continuous biostratigraphic record could not be established, but the section preserves the Givetian/Frasnian boundary. Based on the conodont record, major gaps also occur in the Famennian which confirms earlier results reported from other sections of similar palaeoenvironments in Central Iran. © 2019, Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany, part of Springer Nature.
Bahrami, A. ,
Königshof, P. ,
Boncheva, I. ,
Yazdi, M. ,
Khalaji, M.A.N. ,
Zarei, E. Palaeobiodiversity and Palaeoenvironments (18671608) 98(2)pp. 315-329
Conodont fauna from the Kesheh and Dizlu sections in the North Isfahan province were investigated. Shallow-water and/or near-shore conodonts, mainly belonging to the icriodid–polygnathid biofacies, dominate the conodont fauna. Due to the depositional setting which is characterised by predominantly shallow-water palaeoenvironments and the lack of some important zonal index taxa (e.g. Palmatolepis species), a precise conodont biostratigraphy is difficult to establish. The Kesheh section covers sediments ranging from the Givetian hermanni Zone to disparilis Zone whereas in the Dizlu section, the ranges of Middle triangularis to Uppermost crepida, the marginifera to Upper trachytera, and the Lower and Middle expansa Zones indicate a Famennian age. The stratigraphic range of the Bahram Formation is discussed, and according to literature and new conodont data presented herein, it is likely that the age of the Bahram Formation in central Iran has a stratigraphical range from the Givetian (hermanni Zone) to the late Famennian (Middle expansa Zone). © 2017, Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany.
Salehi, M.A. ,
Sebdani, Z.M. ,
Pakzad, H.R. ,
Bahrami, A. ,
Fürsich, F.T. ,
Heubeck, C. Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 288(1)pp. 49-77
The “Jurassic Gap” between Upper Triassic and Lower Cretaceous siliciclastic strata at the southwestern margin of the Central East Iranian Microcontinent (CEIM) represents the Cimmerian orogenic events. However, the provenance of siliciclastic rocks above and below this prominent unconformity is poorly known, negatively affecting our ability to reconstruct paleogeography and orogenic dynamics. Here, we analyze the provenance of the uppermost Triassic Qadir Member of the Nayband Formation and the red beds of the Lower Cretaceous siliciclastic succession in central Iran, based on conglomerate clast composition, sandstone modal analysis and sandstone geochemistry. Based on the notable compositional variation, we assign the Qadir Member to a transitional continental-tectonic setting and the red beds of the Lower Cretaceous siliciclastic rocks to a recycled-orogen setting. Geochemical analyses shows that the parent rocks of the Qadir Member were intermediate igneous, felsic and metamorphic rocks; and were sedimentary quartz, felsic igneous and metamorphic rocks for the Lower Cretaceous red beds. The modal analysis also indicates semi-humid weathering conditions in the Late Triassic but more humid conditions during the Lower Cretaceous which the strata were largely influenced by the deposition of recycled Jurassic sediments. We infer the Sanandaj–Sirjan Zone (SSZ) to the south to be the main provenance region for both stratal packages. © 2018 E. Schweizerbart’sche Verlagsbuchhandlung, Stuttgart, Germany.
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 287(2)pp. 123-142
Tubes of the characteristic serpulid species Rotularía spirulaea (Lamarck, 1818) are widespread in the Eocene of the Neo-Tethyan Realm. Here they are described from the state of Iran for the first time. Their ultrastructure and the mode of life, paleogeography and palaeoecology of this species are discussed. Rotularia spirulaea occurs in Eocene limestones of the Zefreh area. It is the most abundant member of a fossil association including Nummulites, bivalves, echinoids and crabs. These faunal elements, together with lithology and stratigraphy, provide information about palaeoecological and sedimentological condition of this area. © 2018 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Ernst, A. ,
Königshof, P. ,
Bahrami, A. ,
Yazdi, M. ,
Boncheva, I. Palaeobiodiversity and Palaeoenvironments (18671608) 97(3)pp. 541-552
A bryozoan fauna from the Late Devonian (Frasnian) of the Bahram Formation of the Zefreh section in central Iran contains four species: three trepostomes and one rhabdomesine cryptostome. Two species are new: the trepostome Coeloclemis zefrehensis sp. nov. and the rhabdomesine cryptostome Euthyrhombopora tenuis sp. nov. The trepostome species Cyphotrypa definita Morozova, 1960 and Anomalotoechus ramosus Morozova, 1960 were recorded previously from the Upper Devonian (Frasnian) of the Kuznets Basin. The genera Coeloclemis and Euthyrhombo-pora are recorded from the Devonian for the first time. The fauna is dominated by the erect ramose Euthyrhombopora tenuis sp. nov., with rare occurrences of the massive Cyphotrypa definita Morozova, 1960. The bryozoans indicate low to moderate water energy environment of middle to outer ramp position. © 2017, Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg.
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 283(1)pp. 109-118
The Dizlu and Bagh Sections in the Oligocene - early Miocene Qom Formation (northeast of Isfahan, central Iran) has yielded a rich association of Bryozoa including eleven species belonging to the order Cyclostomata. The description of these eleven species (including three new species (Exidmonea baghi sp.n., Nevianipora isfahani sp.n. and Polyascosoecia iranica sp.n.) increase the knowledge with respect to the faunal diversity within the Qom Formation. © 2017 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Königshof, P. ,
Carmichael, S.K. ,
Waters, J. ,
Jansen, U. ,
Bahrami, A. ,
Boncheva, I. ,
Yazdi, M. Palaeobiodiversity and Palaeoenvironments (18671608) 97(3)pp. 517-540
The Zefreh section in central Iran represents a carbonate ramp succession with a general shallow-marine palaeoenvironment. This section represents most of the Bahram Formation (Givetian to at least Middle falsiovalis Zone) and consists of a very heterogeneous succession of medium- to coarse-grained sandstones, skeletal pack- to grainstones with local biostromes, massive or laminated dolostones, and shales. Microfacies analysis allowed the discrimination of 12 microfacies reflecting supratidal to open marine palaeoenvironments. The shallow-marine environment was investigated using facies analysis and geochemical proxies. Redox conditions in the Zefreh section appear to be primarily oxic and support the facies and sedimentological results. The provenance of the Zefreh sediments using La, Sc, Zr, and Th indicates that they are most likely derived from continental arc volcanics which is consistent with the preliminary tectonic interpretations. Conodonts and brachiopods were used for establishing the biostratigraphical framework. The lack of important zonal index taxa of the widely applied conodont standard zonation requires the application of an alternative shallow-marine conodont zonation. Based on conodont and brachiopod data, the Zefreh section covers sediments ranging from the upper Givetian to lower Frasnian. © 2016, Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg.
Journal Of Sciences Islamic Republic Of Iran (10161104) 28(4)pp. 325-336
The aim of this study is to bridge a gap in the existence of Trilobites in the marine Permian successions of Iran by exploring a stratigraphic section of the Permian in Jamal Formation (Dizlu section). Based on comprehensive field studies and laboratory investigations three Trilobite specimens were identified in the study area including Pseudophillipsia (Carniphillipsia) dizluensis sp. nov., Pseudophillipsia (Carniphillipsia) sagittalis and Pseudophillipsia (Carniphillipsia) sp.. A new occurrence of trilobites collected from the Permian (Wordian) Jamal Formation at a section at Dizlu, Isfahan Province, Iran, is documented. They belong to a new species of Pseudophillipsia (Carniphillipsia), which is described herein, and can be attributed to the a group of species centered on P.(C). paffenholzi (Weber). It is based on 30 specimens from a single horizon, most of which are enrolled. Co-occurrence of Pseudophillipsia (Carniphillipsia) sp. A. and stenohalin groups such as brachiopods, bryozoans, and crinoids are indicating that this species were preferred shallow and carbonate environments. This is the first time that the existences of these specimens are reported in Dizlu section.
Farsani, N.T. ,
Mortazavi, M. ,
Bahrami, A. ,
Kalantary, R. ,
Bizhaem, F.K. Geoheritage (18672477) 9(4)pp. 577-584
Art is a tool for education and can facilitate knowledge transfer and sciences to infants and schoolchildren. Therefore, tourism products such as geotourism which are classified as educational tourism can benefit from art and artists for knowledge transfer from the professional level to tourists, locals and children. In this context, this research has three major purposes: (1) to address how activities and strategies in geotourism can be applied for the purpose of geoknowledge transfer and geo-education; (2) to introduce art, especially handicrafts, as an educational tool for promoting geotourism; and (3) to promote geoproducts inspired by the existence of fossils in Isfahan Province, Iran. On the basis of the results of this study, it can be concluded that integrating traditional art with geological elements can be a strategy for geo-education and popularisation of Earth sciences. © 2017, The European Association for Conservation of the Geological Heritage.
Bahrami, A. ,
Königshof, P. ,
Boncheva, I. ,
Tabatabaei, M.S. ,
Yazdi, M. ,
Safari, Z. Palaeobiodiversity and Palaeoenvironments (18671608) 95(4)pp. 555-577
Four sections of mainly Middle Devonian (Givetian) shallow-marine rocks at the northern margin of Gondwana (Central Iran) were investigated with a special focus on the Bahram Formation, as the stratigraphic range of the Bahram Formation is uncertain and still under discussion. Generally, the Bahram Formation is discontinuously underlain by the Lower Devonian Padeha Formation and disconformably overlain by the Permian Jamal Formation. Conodont communities from the four sections in the Soh area (Najhaf and Neqeleh sections) and the Natanz area (Varcamar and North Tar sections) were investigated. The most widely applied conodont standard zonation of the Upper Givetian contain taxa characteristic of deeper shelf facies whereas conodont fauna of the investigated sections mainly show affinities to shallow-marine environments. Shallow-water conodont associations corresponding to the expansus Zone and subterminus Zone are described from Central Iran for the first time, whereas the vast majority of icriodontid and polygnathid faunas were reported from shallow-marine carbonates around Laurussia (e.g. North America, and Europe). Thirty-six species and subspecies were assigned to five genera (Ancyrodella, Bipennatus, Icriodus, Polygnathus and Pandorinellina). The sedimentological record is characterised by remarkable lateral facies changes, but in the upper part of the Givetian, a general transgressive trend is obvious due to the dominance of limestones and small biostromes. © 2015, Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg.
Bollettino della Societa Paleontologica Italiana (03757633) 53(1)pp. 27-37
The deep-sea hatchetfish clade includes some of the most bizarre stomiiforms, which are characterized by a deep and strongly compressed body, with vertically flattened silvery sides. This peculiar group of mesopelagic fishes consists of three extant and three extinct genera that appeared in the record in the Middle Eocene. A new genus and species of deep-sea hatchetfish, Eosternoptyx discoidalis n. gen. et sp., is described from the Middle to Late Eocene deposits of the Pabdeh Formation exposed a few kilometres east of the city of Ilam, Zagros Basin, Iran. The new deep-sea hatchetfish taxon from Ilam is based on a partially complete specimen in part and counterpart characterized by a remarkably discoid physiognomy of the body and a unique combination of features, including: 28 (13+15) vertebrae; eight pairs of pleural ribs; two posteriormost pleural ribs shortened not reaching the ventral margin of the abdominal keel; six supraneurals; dorsal blade absent; dorsal fin contains 18 rays; first dorsal-fin pterygiophore very large and protruding externally beyond the dorsal profile of the body; possession of two preanal spines; anal-fin origin opposite to dorsal-fin origin; posttemporal and supracleithrum not fused; posttemporal spine absent; body naked. The comparative osteological analysis suggests that Eosternoptyx n. gen. appears to be intermediate between the basal genus Polyipnus and the more derived deep-sea hatchetfish genera Argyropelecus, Discosternon, Horbatshia, Polypnoides, and Sternoptyx.
Bahrami, A. ,
Boncheva, I. ,
Königshof, P. ,
Yazdi, M. ,
Ebrahimi khan-abadi a., Journal of Asian Earth Sciences (18785786) 92pp. 187-200
The record of conodonts related to the Mississippian/Pennsylvanian boundary interval was investigated in four sections in Central Iran from two different structural units. Two sections from the Sanandaj-Sirjan trend zone (Asad-abad, and Darchaleh sections) and two from the East-Central Iran Microplate (Shesh-angosht and Kale-Sardar sections) exhibit a nearly complete record previously described across the Mississippian/Pennsylvanian boundary in Iran. The investigated sections can be subdivided in three formations (Ghaleh-, Absheni-, and Zaluda Formation) which belong to the Sardar Group. The mid-Carboniferous boundary was defined by the occurrence of Declinognathus noduliferus s.l.. Bio-event characteristics of the Carboniferous conodont fauna (Mississippian genera Gnathodus and Lochriea have been replaced by Pennsylvanian genera Declinognathus and Idiognathodus) as well as sedimentological changes within overall shallow water deposits were located approximately 33° S of the paleoequator and suggest sea-level changes within the framework of the Late Paleozoic Ice Age (LPIA). Furthermore, a widespread crinoid marker horizon previously described from two localities in Iran can be subdivided into three units of different ages. © 2014 Elsevier Ltd.
Bahrami, A. ,
Zamani, F. ,
Corradini, C. ,
Yazdi, M. ,
Ameri, H. Bollettino della Societa Paleontologica Italiana (03757633) 53(3)pp. 179-188
The study of the conodont fauna from the Bahram Formation in the Sar-e-Ashk section provides new data on the stratigraphy of this unit in the Kerman Province, Central-East Iran. The study area is located in the southwestern part of the Central-East Iran Microplate. The fauna consists of thirteen species and four taxa in open nomenclature, mainly belonging to the genera Icriodus and Polygnathus, and allows to date the Bahram Formation in the studied section as Frasnian. The shallow water conodont biofacies confirms an inner shelf to foreshore depositional environment for the unit. © 2014 Mucchi Editori s.r.l. All rights reserved.
Neues Jahrbuch fur Geologie und Palaontologie - Abhandlungen (00777749) 274(1)pp. 43-54
We report on decapod crustaceans from the Eocene of Zagros Basin (Baba-Heydar section, Shahr-e-kurd area, Iran). The studied sample includes crustacean penaeids and scyllarids that have been assigned as follows: Eopabdehus nov. gen., with E. babaheydariensis n. sp. (Penaeidae Rafinesque, 1815), Eogordonella nov. gen., with E. iranianiensis n. sp. (Solenoceridae Wood-Mason, 1891), and Parsacus nov. gen., with P. eocenicus n. sp. (Scyllaridae LatReiLLe, 1825). Eogordonella iranianiensis n. sp. is the second report of Solenoceridae in the fossil record. The description of Parsacus nov. gen. allowed to review the extant genus Parribacus dana, 1852, attesting that the fossil species P. cristatus FÖRSTER, 1984, previously included therein, must be assigned to the new genus. © 2014 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.
Bulletin of Geosciences (12141119) 88(2)pp. 369-388
A rich and diverse conodont fauna from upper Frasnian and lower-middle Famennian strata in three sections - Ghale-kalaghu, Howz-e-dorah 1 and Howz-e-dorah 2 - in the southern Shotori Range of central Iran contains forty-five taxa belonging to eight genera, dominated by icriodids and polygnathids, from the Lower rhenana Zone to the velifer Zone (= Uppermost marginifera Zone). A hiatus is documented across the Frasnian/Famennian boundary that possibly includes the Upper rhenana to the Middle triangularis Zone.
Yazdi, M. ,
Bahrami, A. ,
Abbasi, P. ,
Sadeghi, R. ,
Vega, F.J. Boletin de la Sociedad Geologica Mexicana (14053322) 65(2)pp. 225-233
Five species of brachyuran Crustacea from the Middle Miocene are described from the Guri Member of the Mishan Formation in southwestern Iran. The species include the leucosioids Leucosia persica; Seulosia sp. cf. S. rhomboidalis; Myra sp.; the portunoid Portunus withersi and the xanthid Demania ahramensis n. sp. The paleobiogeographic affinities of these genera reinforce previous interpretations of a wide distribution between the Persian Gulf and the Indopacific regions.
Bahrami, A. ,
Mortazavizadeh m.r., ,
Yazdi m.f., ,
Chamani m., Eastern Mediterranean Health Journal (10203397) 18(10)pp. 1055-1059
The value of serum tumour markers in the prognosis of patients with breast cancer is controversial. This prospective study in Yazd, Islamic Republic of Iran, assessed the value of the tumour markers carcinoembryonic antigen (CEA) and cancer antigen (CA) 15-3 in 159 patients with primary breast cancer. CEA and CA15-3 assays (mean 14 per patient) were performed at diagnosis, end of surgery and chemotherapy and every 3 months in the first 2 years and every 6 months in second 2 years of the follow-up period. During follow-up, 33 patients (20.8%) presented symptomatic metastasis. A significant relationship was seen between metastasis status and positive CEA and CA15-3 levels. The sensitivity and specificity were 66.7% and 98.4% for CEA respectively and 84.8% and 91.3% for CA15-3 respectively. Optimum cut-offs were 4.95 ng/mL and 30.5 U/mL for CEA and CA15-3 respectively.
Revista Mexicana de Ciencias Geologicas (10268774) 28(2)pp. 226-234
Funginella? isfahanensis n. sp. is a new nominal solitary scleractiniid coral from the upper Albian of Iran. Its dimensions, associated sedimentary facies and descriptions, all conform to those of the four specimens described as "Funginella sp. 2" in Abdel-Gawad and Gameil (1995, Cretaceous and Palaeocene Coral Faunas in Egypt and Greece: Coral Research Bulletin 4, 1-36) from North Sinai, Egypt. A preliminary discussion on small solitary cupolate coral species is presented.
Rivista Italiana di Paleontologia e Stratigrafia (20394942) 117(2)pp. 199-209
The study of the conodont fauna from the Upper Devonian Shams Abad section provides new data on the stratigraphy of the Bahram Formation in the Kerman province, in southeastern Iran. The fauna includes twenty-four species, mainly belonging to genera Polygnathus and Icriodus, and gives evidence of a late Frasnian to middle Famennian age, in contrast to previous interpretation of the same unit. The shallow water conodont biofacies confirms an inner shelf to foreshore shallow marine depositional environment.
Bollettino della Societa Paleontologica Italiana (03757633) 50(1)pp. 35-53
A rich and diverse conodont fauna represented by fifty-six taxa belonging to fifteen genera is described from three sections (Ghale-kalaghu, Howz-e-Dorah 1 and Howz-e-Dorah 2) in the southern Shotori Range (central Iran). The association, dominated by Polygnathus, has allowed a detailed biostratigraphy across the Devonian/Carboniferous boundary interval to be constructed, ranging from the Uppermost marginifera Zone to the anchoralis-latus Zone. The D/C boundary is narrowly constrained within a condensed interval at the base of the "Mush Horizon" between the Shishtu 1 and Shishtu 2 subformations.
Boletin de la Sociedad Geologica Mexicana (14053322) 62(2)pp. 207-211
Two species of decapod crustaceans are described from upper Albian sediments of Central Iran. The small mecochirid lobster-Huhatanka iranica n. sp. represents the second species of this genus, previously known from the Albian of Kansas, USA. Callianassa sensu lato is reported as an associated crustacean.
Palaontologische Zeitschrift (18676812) 84(4)pp. 485-493
Four decapod crustacean species from the Middle Miocene Mishan Formation of Hormozgan Province, Southern Iran are described. Three species of leucosiid crabs represent the first fossil record for their respective genera outside the Indo-Pacific region. The oldest records for Leucosiasensu lato, Phylirasensu lato, and Arcania are from Middle Miocene deposits of the Indo-Pacific, and thus their paleobiogeographic distribution is extended for this lapse of time. Harpactocarcinus miocenicus n. sp. represents the youngest and most oriental occurrence for a typically Eocene genus, whose species are known mainly from Central Europe. This contribution represents the first formal report for Tertiary crustaceans from Iran. © 2010 Springer-Verlag.
Rivista Italiana di Paleontologia e Stratigrafia (20394942) 113(3)pp. 329-356
Asadabad section in Central Iran is one of the most complete sequences so far described across the Carboniferous of Iran. The stratigraphic and biostratigraphic data on the sediments overlying the Devonian carbonate platform give evidence about the duration of shallow water depositional evolution. There are thirty productive levels with conodonts in the Carbonifeous section ranging in age from early Tournaisian to the top of Bashkirian (Lower expansa - sulcata to sinuosus zones). There is scarce evidence about the elongatus Zone presence - Late Pennsylvanian. Sulcata to anchoralislatus conodont zones in Shishtu Formation and muricatus to sinuosus Zone and a possible elongatus Zone in Sardar Formation have been indentified. These conodont zones are reported for the first time in that area. A crinoidal limestone - key bed horizon, is traceable in the studied area as well as in other parts of Iran. It is Early Pennsylvanian - Bashkirian in age and is correlated to sinuatus-minutus Zone. The studied Shishtu and Sardar Formations (Carboniferous) as well as Vazhnan and Surmaq Formation (Permian) in the section belong to marine near shore sedimentation with many macrofaunal remains.
Acta Geologica Polonica (00015709) 56(3)pp. 229-240
Two successions of Carboniferous sedimentary rocks in Central Iran yielded ammonoid assemblages from one horizon each. In the Ramsheh section, a siltstone with Neoglyphioceras yazdii n. sp. and Dombarites can be assigned to the latest Viséan. The assemblage from the Shesh Angosht Mountain is more diverse with species of the genera Proshumardites, Eumorphoceras, Homoceras, Glaphyrites, Syngastrioceras, and Dombarocanites. This is the first time that the co-occurrence of the genera Eumorphoceras and Homoceras has been recorded. This fauna contains elements of the South Urals and Central Asian occurrences of Bashkirian ammonoids and suggests close palaeobiogeographic relationships.