Stratigraphy and Palaeontology
Abbas Ghaderi; Mahdi Badpa; Ali Reza Ashouri
Abstract
To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals ...
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To study of Permian corals at the northwest of Iran, Ali-Bashi stratigraphic section was selected and sampled. After microscopic studies of several longitudinal, transverse, and serial sections were obtained from more than 180 coral fossils, 12 species belonging to 6 genera of rogues and tabula corals were determined. The Permian succession of the Julfa area is the dominion of two types of coral fauna. Waagenophyllidae fauna that is the territory of the colonial coral forms comprises typically Tethyan indicators such as Ipciphyllum and Waagenophyllum with the age of Middle?- Late Permian. Cyathaxonia fauna, Late Permian in age, include terminal phylogenetic representatives of the rugose corals, mostly composed of solitary one Pentaphyllum. This genus is persistent till the vicinity of the extinction horizon at the near end Permian in the Ali Bashi Formation topmost horizon. Also, the last standing tabula coral before the Late Permian extinction in the Julfa region is the genus Protomichelinia. The Permian coral fauna of the NW Iran finely corresponds to those of the Abadeh region in Central Iran and Transcaucasus. The Waagenophyllidae forms are the same as South China fauna, whereas the Cyathaxonia ones reveal a high endemism in the Late Permian of NW Iran.
Stratigraphy and Palaeontology
mahdi badpa; Hamed Yarahmadzahi; Kaveh Khaksar
Abstract
The Anarak Group with Zaladu (Gzhelian-Asselian age) and Tigh-e-Madanu (Sakmarian age) formations in the Ozbak Kuh Mountains (Central Iran) is more than 180 m thick and includes thick units of conglomerate, shale, sandstone, calcareous sandstone, sandy limestone, fusulinid limistone, marl and dolomite ...
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The Anarak Group with Zaladu (Gzhelian-Asselian age) and Tigh-e-Madanu (Sakmarian age) formations in the Ozbak Kuh Mountains (Central Iran) is more than 180 m thick and includes thick units of conglomerate, shale, sandstone, calcareous sandstone, sandy limestone, fusulinid limistone, marl and dolomite layers. In the sequence of Zaladu formation, the accumulation of coral species of Pseudozaphrentoides winsnesi Flügel, 1995, was abundantly identified in two horizons in the upper part of the Ghezelin layers. Based on fuanal composition, diversity and abundance, spacing of corallits and microfacies, the mentioned accumulation is categorized as low-level (of Type A, ecological zone of A2). This zone represents a tough ecological condition where only a limited number of solitary corals could have survived the life-threatening factors. Based on microfacies studies, the coral community was identified to be restricted to the shoal and around it (lagoon toward shoal and open sea toward shoal) in a shallow platform.
