Iranian Sections Research Articles

Molecular phylogeny of Cousinia sections Albidae, Stenocephalae and Cousinia (Asteraceae): Systematic implications

Cousinia sect. Stenocephalae is a mainly Iranian section of the genus and the second largest section of Cousinia after C. sect. Cynaroidae. Its members are mainly distributed in Iran. Using nrDNA ITS sequences, together with morphological evidence where possible, we tested the monophyly of C. sect. Stenocephalae as well as the related C. sect. Albidae and C. sect. Cousinia. We reconstructed phylogenetic relationships within these sections by performing a Bayesian analysis on a sample of 153 species of Cousinia, of which 49 species belong to the study sections. The analysis revealed that C. sect. Stenocephalae, Albidae and Cousinia are not monophyletic, which lays stress upon the need of a deep reexamination of the sectional classification in Cousinia using a different approach.

Ostracods from the end‐Permian mass extinction in the Aras Valley section (north‐west Iran)

AbstractThe Aras Valley section (north‐west Iran) exposes a sedimentary succession that allows the study of ostracod diversity patterns during/across the end‐Permian mass extinction. For the present study, 59 samples were investigated for their ostracod abundances, which ranged from 4 to 31 500 specimens per 500 g. In 45 sample horizons, the ostracods were identified to the species level. In total, 3 425 specimens were determined and 62 species were identified, of which one genus and ten species are described for the first time: Fabalicypris veronicae Gliwa, sp. nov., Orthobairdia capuliformis Gliwa, sp. nov., Araxobairdia formosa Gliwa, gen. et sp. nov., Bairdiacypris kathleenae Gliwa, sp. nov., Eumiraculum mettei Gliwa, sp. nov., Liuzhinia julfensis Gliwa, sp. nov., Carinaknightina hofmanni Gliwa, sp. nov., Cavellina fosteri Gliwa, sp. nov., Cavellina hairapetiani Gliwa, sp. nov. and Hungaroleberis striatus Forel, sp. nov. The assemblages show, at the end‐Permian mass extinction event, a complete turnover from a low‐diversity Fabalicypris‐dominated pre‐extinction community to a more diverse Bairdiacypris‐dominated post‐extinction community. The turnover coincides with the significant temperature increase that was previously recorded from north‐west Iranian sections. The low diversity in the horizon immediately below the extinction horizon indicates that environmental changes, such as thermal stress, may have had an impact on the ostracod assemblages prior to the extinction event. In comparison with other diverse ostracod assemblages from the Palaeotethyan realm, the ostracods of the Aras Valley section are not associated with microbialites.

Santonian-Maastrichtian carbon-isotope stratigraphy and calcareous nannofossil biostratigraphy of the Zagros Basin: Long-range correlation, similarities and differences of carbon-isotope trends at global scale

Abstract A high-resolution study of carbon isotope stratigraphy and calcareous nannofossil biostratigraphy has been undertaken on the Upper Cretaceous sediments of the Gurpi Formation (Fm.) in the Bowan section (Zagros Basin, Iran). The integrated stratigraphy of the section allows for large-scale correlation with Upper Cretaceous reference sections (Gubbio, Italy; German Chalk; Shahneshin, Iran) and suggests the age of the Gurpi Fm. at Bowan to be latest Santonian to early Selandian. Correlation of the isotopic data from Bowan to the Shahneshin section in the central Zagros mountains shows remarkable similarity that may be related to effects specific to the peculiar stratigraphy of the area and, possibly, to the long-term evolution of seawater δ13C in the Zagros Basin. A sequence stratigraphic framework is proposed for both sections. Correlation of the two sections to data from the Boreal realm, Indian Ocean, equatorial Pacific Ocean, and other Tethyan sections suggests that it is possible to identify some of the previously defined major carbon isotope events in the Iranian sections. Significant differences, however, are observed in absolute values and overall amplitude of carbon isotope trends. In particular, our results show that the Santonian/Campanian boundary event (SCBE) which is a well-defined, double-peaked, positive excursion at Gubbio and in the Boreal realm is absent in the Zagros Basin, eroded by a major sequence boundary. Moreover, the most pronounced feature in Upper Cretaceous carbon isotope ratios of the Zagros Basin carbonates is an overarching maximum culminating in the early Campanian which correlates with a discrete, low-amplitude (0.25‰) positive excursion defined as the papillosa Zone event at Gubbio and in the Boreal realm. Our results thus reveal a contrasting evolution of carbonate δ13C during the early Campanian between different oceanic basins but also within the Tethys.

Biochemostratigraphy of an upper Albian–Turonian succession from the southeastern Neo-Tethys margin, SW Iran

A Neo-Tethyan upper Albian–Turonian (hemi-)pelagic carbonate succession (Sarvak Formation), accessible in outcrop in the Zagros, SW Iran, was investigated using sedimentology, microfacies analysis, planktonic foraminifera biostratigraphy, and carbon-isotope stratigraphy. The succession contains six biozones including Thalmanninella (Th.) appenninica, Th. globotruncanoides, Rotalipora cushmani, Whiteinella archaeocretacea, Helvetoglobotruncana Helvetica, and Marginotruncana schneegansi. Some of these biozones show variable stratigraphic positions throughout the Tethyan and Boreal realms that hinder correlation of the studied Iranian section with European reference sections. Therefore, the correlation of the existing biostratigraphic framework was complemented by carbonate carbon-isotope stratigraphy based on bulk carbonate material. Despite the low resolution of the presented carbon-isotope record, pronounced global events including the late Turonian Events, Cenomanian/Turonian Boundary (CTB) Event (OAE 2), and Albian/Cenomanian Boundary (ACB) Event can be distinguished. The δ13C excursions provide global synchronous time-lines for correlation. The distinguished biozones were compared among the sections regarding their stratigraphic positions relative to these time-lines. The correlation tentatively suggests that the biostratigraphic datum marking the ACB is diachronous with an SE–NW trend. First appearance datum (FAD) of Th. appenninica varies from the upper Albian to the lower Cenomanian. The FAD of Th. globotruncanoides is also variable from the upper Albian to the lower Cenomanian. However, the middle Cenomanian–Turonian biozones including Rotalipora cushmani and Whiteinella archaeocretacea zones are synchronous. Elevated pCO2 contributed to the gradual increase of the SST (sea surface temperature) during the Cenomanian, and the dramatic climax at the earliest Turonian. This trend closely correlates with the change from the diachronous ACB-biozones to synchronous CTB-biozones. Possibly, increasing SSTs provided temperature-tolerance range for the species throughout different latitudes, and assisted their rapid distribution. Moreover, the warming raised the sea level from the latest Albian to Turonian that inundated landbridges, resulting in an enhanced marine circulation and faster distribution of planktonic species throughout the Neo-Tethys Ocean.

Siberian Trap volcanism, global warming and the Permian-Triassic mass extinction: New insights from Armenian Permian-Triassic sections

AbstractPermian-Triassic boundary sections from Armenia were studied for carbon isotopes of carbonates as well as oxygen isotopes of conodont apatite in order to constrain the global significance of earlier reported variations in the isotope proxies and elaborate the temporal relationship between carbon cycle changes, global warming and Siberian Trap volcanism. Carbon isotope records of the Chanakhchi and Vedi II sections show a 3–5‰ negative excursion that start in the Clarkina nodosa (C. yini) conodont Zone (latest Permian) with minimum values recorded in Hindeodus parvus to Isarcicella isarcica conodont zones (earliest Triassic). Sea surface temperatures (SST) reconstructed from oxygen isotopes of conodont apatite increase by 8–10 °C over an extrapolated time interval of ∼39 ka with the onset of global warming occurring in the C. iranica (C. meishanensis) Zone of the latest Permian. Climate warming documented in the Armenian sections is comparable to published time-equivalent shifts in SST in Iran and South China suggesting that this temperature change represents a true global signature. By correlating the Armenian and Iranian section with the radiometrically well-dated Meishan GSSP (Global Stratotype Section and Point) section (South China), the negative shift in δ13C is estimated to have occurred 12–128 ka prior to the onset of global warming. This temporal offset is unexpected given the synchrony in changes in atmospheric CO2 and global temperature as seen in Pleistocene ice core records. The negative δ13C excursion is explained by the addition of emission of isotopically light CO2 and CH4 from thermogenic heating of organic carbon-rich sediments by Siberian Trap sill intrusions. However, the observed time lag in the δ13C and δ18O shifts questions the generally assumed cause-effect relationship between emission of thermogenically produced greenhouse gases and global warming. The onset of temperature rise coincides with a significant enrichment in Hg/TOC (total organic carbon) ratios arguing for a major volcanic event at the base of the extinction interval. Whether global warming was a major factor for the Late Permian mass extinction depends on the duration of the extinction interval. Warming only starts at the base of the extinction interval, but with the extinction encompassing a time interval of 60 ± 48 ka, global climate warming in conjunction with temperature-related stressors as hypoxia and reduced nutrient availability may have been one of the major triggers of the most devastating biotic crisis in Earth history.

<p><strong>Systematic significance of seed morphology in <em>Acanthophyllum</em> (Caryophyllaceae: tribe Caryophylleae) in Iran</strong></p>

Acanthophyllum, with ca. 90 spiny cushion-forming species, is one of the largest genera of Caryophyllaceae. Although taxonomic utility of seed morphology has already been highlighted in different genera of Caryophyllaceae, the systematic value of seed characters in Acanthophyllum has not been adequately addressed. In order to evaluate the application of seed morphology in infrageneric classification of Acanthophyllum, we surveyed seed characters in the five Iranian sections of Acanthophyllum. Seed morphology of 32 accessions of Acanthophyllum representing 21 species and four sections were investigated using scanning electron microscopy. Seed morphological characters of two species from one additional section were included based on previous studies in the Caryophyllaceae. Seeds in the majority of examined species are oblong in outline. Five types of seed surface can be considered: reticulate, reticulate-papillate, colliculate, colliculate-papillate, and colliculate-columellate. Papillae type is a reliable character for separation of certain natural groups within Acanthophyllum. Seed features provided strong evidences for separating sections, especially the following ones: Acanthophyllum, Macrostegia and Pleiosperma, whose seeds showed a high degree of uniformity among the sampled species. Morphological characteristics of seeds were less useful for discriminating Acanthophyllum species. While seed characters are consistent within individual populations, they can vary among different populations of an individual species. Our results show that variation in seed morphological characters are in agreement with phylogenetic patterns within Acanthophyllum.

Anachronistic facies and carbon isotopes during the end-Permian biocrisis: Evidence from the mid-Tethys (Kisejin, Iran)

Late Permian mass extinction (LPME) research has focused primarily on Tethyan sections because it is believed that these successions are more complete than those from other localities, and provide a more comprehensive record of the largest, most devastating extinction event in Earth history. The Kisejin section, a previously undocumented mid-Tethyan, Upper Permian-Lower Triassic succession located in the Central-Iran Plate. The Kisejin section contains a continuous Permian-Triassic sequence with only small breaks in sedimentation and was examined in order to determine sedimentologic, biostratigraphic, and carbon isotopic trends across the Permian-Triassic transition. Abnormal (anachronistic) carbonates developed in the study area following the LPME, and include microbialites, edgewise conglomerates, sparitic microspheres, and microbially-coated grains; microbialites occur as thrombolites, stromatolites, and as agglutinated forms. Renalcis-type calcimicrobes are documented for the first time from Permian-Triassic boundary microbialites (PTBMs) of Iran. Coated grains fall into two groups, and include pre-PTBM ooids, which are dense and cloudy, and possibly microbial in origin, and post-PTBM cortoids with destructive and constructive micrite envelopes. Latest Permian conodonts (H. praeparvus, M. ultima), coupled with carbon isotopic values, place the Permian-Triassic boundary within the lowermost thrombolite unit, about 2.1 m above the boundary between the Nessen Formation and the Elika Formation, and indicate that microbialite growth began during the latest Permian. Our study of this previously unknown section shows that, unlike other well-known PTB sections from Iran, the microbialite pattern is complicated, and is more similar to PTBM successions from Turkey. In addition, we note a similarity between the unusual facies of the Kisejin section and those of eastern Tethyan sections from China (i.e. sparry microspheres and Renalcis-type calcimicrobes); these unusual facies have not been previously reported from other well-known Iranian sections, including Julfa and Abadeh, which are thick and have been extensively studied.

Integrated stratigraphy, facies analysis and correlation of the upper Albian–lower Turonian of the Esfahan area (Iran): Unravelling the conundrum of the so-called “Glauconitic Limestone”

The so-called “Glauconitic Limestone of Esfahan” is a thin (<4 m) but very conspicuous lithological unit that is well known for its late Albian to middle Cenomanian ammonite faunas. However, it consists of two genetically unrelated stratigraphical units: the lower part commonly comprises fine-grained bioclastic limestones that are poor in macrofossils and rest with a sharp basal surface on mid-upper Albian strata of the deep-marine Bazyab Formation; the microbiostratigraphy shows this part to be mid-late Albian in age (Pseudothalmanninella ticinensis Zone), thus constituting a lithostratigraphical equivalent of the lower Debarsu Formation. The upper part of the “Glauconitic Limestone” consists of a fossiliferous glauconitic conglomerate with large rounded limestone pebbles to boulders and phosphatized bio-/lithoclasts, yielding the famous ammonite faunas of the unit. It has a major erosional unconformity at its base that may cut out the Debarsu Formation over short distances and it shows a fining-upward trend grading into an overlying marl and argillaceous limestone unit. These observations demonstrate that the glauconitic conglomerate initiated a new depositional cycle and is thus genetically related to the overlying fine-grained strata. Consequently, the glauconitic conglomerate is regarded as the basal Takhte-Sheitan Member (new) of the Kolah-Qazi Formation (new), formalized herein. The matrix of the upper part of the Takhte-Sheitan Member could be dated as mid-late Cenomanian (upper Rotalipora cushmani Zone) and the overlying fine-grained offshore deposits of the Kolah Qazi Formation as latest Cenomanian to early Turonian by means of foraminifera, ammonites, inoceramid bivalves and carbon stable isotopes. Thus, the late Albian to middle Cenomanian phosphatized ammonites from the Takhte-Sheitan Member are derived, i.e., represent classic remanié faunas. The Takhte-Sheitan Member is regarded as a complex, condensed transgressive lag onlapping a considerable palaeotopography after a late mid- to early late Cenomanian tectonic event. The overlying marl and argillaceous limestones of the Kolah-Qazi Formation indicate a considerable deepening in response to a major eustatic sea-level rise and highstand across the Cenomanian–Turonian boundary associated by increased organic carbon burial related to the oceanic anoxic event (OAE) 2. The carbon stable isotope curve from the base of the Kolah-Qazi Formation (Takhte-Sheitan Member) up-section into the marls and argillaceous limestones shows the conspicuous structure of the major positive excursion of the OAE 2 and serves as precise tool for the high-resolution chemostratigraphic calibration of the Iranian sections. It provides a new reference curve for the OAE 2 in the Middle East.

Sea level drop, palaeoenvironmental change and related biotic responses across Guadalupian–Lopingian boundary in southwest, North and Central Iran

AbstractThe Capitanian to Wuchiapingian deposits in Zagros (southwest Iran), Alborz (North Iran) and Central Iran display important information about the end-Guadalupian extinction. According to lithological characteristics in the studied sections, the Guadalupian–Lopingian boundary (G-LB) interval can be subdivided into three units: the Capitanian unit, the latest Capitanian unit or interval unit (i.e. deposits in the topmost portion of the Capitanian strata) and the Wuchiapingian unit. The G-LB horizon is set at the base of Wuchiapingian deposits based on the first appearance datum (FAD) of the Late Permian diagnostic small foraminifers. The Capitanian unit was deposited subtidally, but the latest Capitanian unit was in the intertidal zone. The Wuchiapingian unit shows the return of subtidal conditions. A remarkable subaerial exposure occurs at the top of the Ruteh Formation, in Alborz, which is a laterite/bauxite horizon followed by continental deposits. The overall facies change in the G-L boundary intervals in the sections under study indicates a sea level drop around the G-LB which was at its lowest level in the Ruteh section. The decline and elimination of shallow marine biota in the G-LB interval took place in two steps in the Zagros and Alborz sections and in one step in Central Iran. These are indicative of the appearance of the stressful environment during the late Capitanian shallowing trend before the G-LB. The sea level drop and regression in the late Capitanian can be considered the major causes of end-Guadalupian extinction in the Iranian sections, but in the Alborz area volcanic activity is another feasible cause of this crisis.

Early to Middle Ordovician lingulate brachiopods from the Lashkarak Formation, Eastern Alborz Mountains, Iran

Popov, L.E., Ghobadi Pour, M. & Hosseini, M., March, 2008. Early to Middle Ordovician lingulate brachiopods from the Lashkarak Formation, Eastern Alborz Mountains, Iran. Alcheringa 32, 1–35. ISSN 0311-5518. Low- to moderate-diversity faunas of lingulate brachiopods are reported for the first time from the Lower to Middle Ordovician Lashkarak Formation of the Eastern Alborz Mountains in northern Iran. Twenty-three species of 20 genera referable to four successive lingulate brachiopod assemblages are systematically described, including Aipyotreta conferta sp. nov., Ghavidelia damghanensis gen. et sp. nov. and Thysanotos multispinulosus sp. nov. The occurrence of Alichovia and Acrotreta, and the early appearance of Biernatia suggest Baltic affinities of the fauna, but scaphelasmatids and Myotreta are missing in the Iranian section. The opportunistic Thysanotos – Leptembolon Association appears in Eastern Alborz in the lower Floian prior to the onset of the carbonate sedimentation.

Reck, Christiane, Mitteliranische Handschriften Teil I: Berliner Turfanfragmente manichäischen Inhalts in soghdischer Schrift. [Verzeichnis der Orientalischen Handschriften in Deutschland Band XVIII, 1

Between the years 1902 and 1914 four expeditions were sent to East Turkestan by the Berlin Museum of Volkerkunde. Among the manuscript remains brought to Berlin by the so-called German Turfan Expedition one finds a substantial number of texts in Middle Iranian. Those in Sogdian are the most numerous; they comprise Buddhist texts in Sogdian script, Manichaean in both Manichaean and Sogdian scripts, Christian in Syriac and Sogdian scripts, and miscellaneous (secular, medical, etc.) texts in Sogdian script. Recently, some, though not many, even in Brāhmi script have come to light. In view of the number of work done on these materials and the period of time which has passed since they were first brought to Berlin, it may come as a great surprise that the book under review is the very first catalogue of the Iranian manuscripts in Sogdian script belonging to the German Turfan collection. One cannot contain one’s emotion to see that almost a half century has elapsed since the first catalogue of the Iranian section of the collection was published by the late Professor Mary Boyce: A catalogue of the Iranian manuscripts in Manichean script in the German Turfan collection, Berlin: Akademie Verlag, 1960. This catalogue belongs to the extensive series “Catalogue of Oriental Manuscripts in Germany (Verzeichnis der Orientalischen Handschriften in Deutchland)” and in the same series there have appeared several other catalogues which deal with the manuscripts belonging to the German Turfan collection. Among those published so far in this series J. Wilken’s volume (Manichaisch-turkische Texte der Berliner Turfansammlung, Stuttgart, 2000) merits special mention, because it lists and describes

Evidence for recurrent changes in Lower Triassic oceanic circulation of the Tethys: The δ13C record from marine sections in Iran

Stable carbon isotope curves derived from Lower Triassic carbonate rocks from three Iranian sections are established to investigate changes in the carbon cycle during the Early Triassic in this area. The sections are located in the south-center (Abadeh), north (Amol), and northwest (Zal) of Iran. All three curves show a similar pattern starting out with high δ 13C values in the uppermost Permian decreasing across the Permian–Triassic boundary, an increase toward more positive values during the Griesbachian that slowly increase further up during the Dienerian, followed by a positive excursion to values as high as + 8‰ near the Dienerian/Smithian boundary. During the Smithian values return to below 0‰, whereas second positive excursion to values higher than + 3‰ is recorded at the Smithian/Spathian boundary, again followed by a drop in δ 13C into the Spathian and a final excursion to positive values at the Spathian/Anisian boundary. The results from these Iranian sections are consistent with previous studies from Italy and China, thus strongly suggesting that the recorded δ 13C variability represents at least Tethys-wide geochemical signals. Moreover, the new curves reveal evidence of high-amplitude, frequent oscillations pointing toward rapid and profound changes in the global carbon cycle during the Lower Triassic. Stratification of the ocean interrupted by episodic overturning transporting deep water to the ocean surface is a viable mechanism to account for the recorded isotope variations. Provided that the δ 13C curve is representative of the global Lower Triassic ocean, it has high potential for accurately dating sedimentary successions via chemostratigraphy.

Biostratigraphy and event stratigraphy in Iran around the Permian–Triassic Boundary (PTB): Implications for the causes of the PTB biotic crisis

The conodont succession and stratigraphic events around the Permian–Triassic boundary (PTB) have been investigated in detail in the open sea deposits of Iran (Abadeh and Shahreza in central Iran, and Jolfa and Zal in northwestern Iran). This investigation produced a very detailed conodont zonation from the Clarkina nodosa Zone up to the Isarcicella isarcica Zone. All significant events have been accurately located and dated within this zonation, and the duration of most of these conodont zones has been calculated by cross-correlation with continental lake deposits that display obvious Milankovitch cyclicity. The unusually short duration of all conodont zones in the interval from the C. nodosa up to the Hindeodus parvus Zone indicates that there was persistent high ecological stress during this time interval. Most of the conodont zones can be accurately correlated with South China. In the interval from the C. hauschkei Zone to the H. parvus Zone, even correlation with the Arctic is possible. Within three thin stratigraphic intervals, the Changhsingian (Dorashamian) warm water conodont fauna of the C. subcarinata lineage is replaced by a cool water fauna with small H. typicalis, rare Merrillina sp., and cool water Clarkina that have very widely spaced denticles. The uppermost cool water fauna horizon comprises the lower C. zhangi Zone and can be accurately correlated with continental beds by recognition of a short reversed magnetozone below the long uppermost Permian–lowermost Triassic normal magnetozone. In Iran and Transcaucasia, this short reversed zone comprises the upper C. changxingensis– C. deflecta Zone and most of the C. zhangi Zone. Its top lies 50 cm below the top of the Paratirolites Limestone (s.s.) in the Dorasham 2 section, which is at the beginning of the upper quarter of the C. zhangi Zone. In the Germanic Basin, this short palaeomagnetic interval comprises the lower and the basal part of the upper Fulda Formation. On the Russian Platform, the Nedubrovo Formation belongs to this short reversed magnetic interval. In its upper part (corresponding to the top of the lower C. zhangi Zone, see above) there is a fallout of mafic tuffs from the Siberian Trap event that originated about 3000 km away in eruption centres in the Siberian Tungusska Basin. In the Germanic Basin and in Iran, this horizon contains volcanic microsphaerules. Thus, a direct correlation can be made between the immigration of a cool water fauna into the tropical realm and an exceptionally strong interval of explosive activity during the Siberian Trap volcanic episode. These faunal changes are the same as those found at the base of the Boundary Clay, suggesting that a short cooling event at this horizon also was due to intense volcanism. Additional influence by a bolide impact cannot be excluded. Most of the events in the interval from the C. nodosa up to the I. isarcica Zone (upper Changhsingian to middle Gangetian) in the Iranian sections can be also observed in other marine sections (e.g., in Meishan) and even in continental sections of the Germanic Basin. Of particular significance is the fact that, in the investigated Iranian sections, the PTB lies either in red sediments or in light grey sediments (as in Abadeh) that contain an ostracod fauna indicative of highly oxygenated bottom waters. Therefore, anoxia cannot be the reason for the PTB extinction event in this region, even though anoxia does cause locally or regionally elsewhere an overprint on the extinction event.