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Upper Triassic (Norian-Rhaetian) dinoflagellate cyst zonation of Nayband Formation, Tabas Block, East - Central Iran
No full textDue to lack of well-preserved fossils and appropriate data on the Upper Triassic strata in Iranian Plate and impor- tance of the strata in terms of hydrocarbon source potential, paleoenvironmental and paleoclimate investigations of Tethys basin. In this research we applied a palynological study on the Late Triassic (Norian-Rhaetian) Nayband Formation, East- Central Iran, to evaluate precise age of the rock unit, its stratigraphic framework and related palaeoenvironmental changes. The studied section attains a thickness of 800 meters and consists of shales, sand- stones and some interbedded limestones. Palynological assessments deduced reasonably diverse and moderately preserved terrestrial and marine palynomorphs which lead to identification of Rhaetogonyaulax rhaetica Zone of the Rhaetogonyaulax Superzone and led to an age of Norian-Rhaetian for the rock units. The recovered palynoflo- ras comprise 23 species belong to 15 genera, including radially symmetrical and monolete spores. Representatives of trilete spores as Dictyophyllidites mortonii, Kyrtomisporis laevigatus, and Gleicheiniidites senonicus are essen- tially abundant in the palynofloras examined. The assigned age is also confirmed by the association of some key misopore species as Annulispora folliculosa and Polycingulatisporites mooniensis. The recovered dinoflagellate cysts exhibit close resemblances with those recorded in Australia, Northwest Europe, Arctic Canada and North- ern Iran. Additionally, based on the detected marine palynomorph associations, accompanied by spore grains, a nearshore depositional environment has been suggested for the studied deposits in Tabas Block of Iran
Disentangling climate signal from tectonic forcing: The Triassic Aghdarband Basin (Turan Domain, Iran)
Get PDFThe Middle–Upper Triassic Aghdarband Basin, NE Iran, consists of a strongly deformed marine and non-marine stratigraphic succession, deposited along the southern margin of Asia in a highly complex tectonic context related to a back-arc setting. The youngest deformed units of the Aghdarband area consist of a rather monotonous sequence of brown-colored shales, with intercalations of siltstones and fine-grained sandstones forming the Miankuhi Formation. The shale-dominated Miankuhi Formation rests on an unconformity surface, separating it from the underlying Sina Formation. A multidisciplinary study based on sedimentological, palynological, and paleobotanical data permits to reconstruct the depositional environments, sedimentary evolution, and paleoclimate conditions of the upper Sina and the lowermost Miankuhi formations. The palynological association of the lowermost part of the Miankuhi Formation yielded sporomorphs of the latest early Carnian to early late Carnian age. Qualitative and quantitative analyses document a shift from xerophytic associations in the upper Ladinian (upper Sina Formation) to hygrophytic assemblages in the Carnian (lower Miankuhi Formation). This increase in hygrophytic elements is also observed in coeval Tethyan outcrops at the same latitudinal belt, suggests a more humid climate in the lower part of the Miankuhi Formation, and correlates this part of the succession
with a record of the Carnian Pluvial Episode. The sedimentological and stratigraphical analyses show an evolution from prodelta to delta setting in the upper Sina Formation, then an unconformity enhanced by an interval of fluvial deposits with histosol levels in the basal Miankuhi Formation, in correspondence with the hygrophytic assemblages. The unconformable boundary between the Miankuhi and the Sina formations is, consequently, interpreted as a result of the sea-level fall associated with the humid climate shift, occurring in close association with the first effects of the Eo-Cimmerian Orogeny along the suture zone, taking to a regional reorganization of the basins architecture and the end of volcanic activity in the back-arc region. The main deformations related to the Eo-Cimmerian event thus, correspond in the Aghdarband Basin to the tectonic event that deformed the Miankuhi Formation. This event is probably older than the middle Norian (217.1 ± 1.7 Ma) but younger than the late Carnian, testifying to a diachronicity in the record of collision along the Iranian Cimmerian blocks and Southern Laurasia according to the different considered structural positions
A MONOTYPIC STAND OF NEOCALAMITES IRANENSIS N. SP. FROM THE CARNIAN PLUVIAL EPISODE (LATE TRIASSIC) OF THE AGHDARBAND AREA, NE IRAN (TURAN PLATE)
Get PDFThe Aghdarband Basin in the Kopeh-Dagh Range (NE Iran) is one of the most important areas for unraveling the evolution of the Turan plate (southern margin of Eurasia) during the last phase of the closure of the Paleotethys and to reconstruct the history of the Cimmerian blocks just before their collision with Eurasia during the early Late Triassic. The youngest sediments affected by the Early Cimmerian orogeny are those of the Upper Triassic Miankuhi Formation, which covers unconformably the Upper Triassic (lower Carnian) marine beds of the Sina Formation by an interval of continental facies including local conglomerates, cross-bedded sandstones, mudstone layers, silty shales, an up to one-meter thick coal layer with plant remains, and shales. The plant assemblages represent a relatively wide variety of different forms (sphenophytes, ginkgophytes, conifers, and incertis sedis), documenting wetlands with lush vegetation typical of warm and humid environments. In this study, we describe a plant fossil assemblage from the base of the Miankuhi Fm., dominated by roots and vegetative organs of Neocalamites iranensis n. sp., with few plant fossils of uncertain botanical affinity. Palynological investigations of the basal part of the Miankuhi Formation confirm a latest early Carnian to late Carnian age for this interval and reveal, for the first time, a clear link between this plant-bearing bed, and a time of global environmental changes, the Carnian Pluvial Episode. This is the first report of the Carnian Pluvial Episode in the Turan plate (southern margin of Eurasia) and Iran
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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