Stratigraphy and Palaeontology
Toran Khamoshi; Ahmad Lotfabad Arab; Mohammad Reza Vaziri
Abstract
In order to study the Lower Cretaceous deposits' coral fossils, the Baghin section was chosen and sampled. This section consists of a sequence of green marl, limestone and shaly limestone deposits. In this section, diverse groups of microfossils (orbitolinids, algae and ostracods) and macrofossils ...
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In order to study the Lower Cretaceous deposits' coral fossils, the Baghin section was chosen and sampled. This section consists of a sequence of green marl, limestone and shaly limestone deposits. In this section, diverse groups of microfossils (orbitolinids, algae and ostracods) and macrofossils (corals, echinoids, bivalves, brachiopods, gastropods,…) are present. The presence of diverse collection fossils, especially large orbitolinid foraminifera indicated a favorable environmental conditions and absence of planktonic foraminifera indicated shallow environmental conditions. Also, the presence of platycopid and podocopid ostracods and corals confirm the shallow, warm, light and suitable paleoecological conditions.
behnam pashazadeh; Davood Jahani; razieh Lak; Hamid nazari; masoud zamani pedram
Abstract
The purpose of this research is to identify quaternary units and determine the sediment boundaries around Yazd city in Central Iran. The origin of Quaternary sediments is mainly related to erosion of the Triassic, Cretaceous, and Palaeozoic units. Based on the results of sedimentation, six types of facies ...
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The purpose of this research is to identify quaternary units and determine the sediment boundaries around Yazd city in Central Iran. The origin of Quaternary sediments is mainly related to erosion of the Triassic, Cretaceous, and Palaeozoic units. Based on the results of sedimentation, six types of facies were identified as Mud, silt, sandy silt, silty sand, mud sands and sandy mud. The XRD results of the samples show that these specimens consist mainly of quartz, calcite, dolomite, feldspar, coperite and clay minerals. In the fossil studies of two important species of ostracodes called Ilyocypris sp. Which refers to sweet waters and Candona .sp, which relate to various saline waters. Due to the diversity of facies and fossils, approximately the lake in the study area was developed in late Quaternary. Facies characteristics, the type of minerals and index fossils indicate that the sedimentation of these facies in a sedimentary lake environment that was first identified in the study area.
R. Haftlang; M. Afghah; S. A. Aghanabati; M. Parvaneh Nezhad Shirazi
Abstract
Lithological and biological Sequences of Cretaceous in Bahar section, Located in South Esfahan (147 m. true thickness) include grayish olive green pencil- like shales containing Budantysras Ammonites (Albian) interbedded with limy shales. which are covered by glauconitic Sandy Limestone (Early Turonian) ...
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Lithological and biological Sequences of Cretaceous in Bahar section, Located in South Esfahan (147 m. true thickness) include grayish olive green pencil- like shales containing Budantysras Ammonites (Albian) interbedded with limy shales. which are covered by glauconitic Sandy Limestone (Early Turonian) (with erosional discontinuity). These sandy limestones are wackestone and rarely greenstone, according to Dunham classification. Based on Biozone divisions, this unit is related to Biozone No. 27 presented by Wynd (1965) and it is equivalent to Sarvak Formation in Zagros. Marly limestone and limestone containing Inoceramus bivalve interbedded with marl dating back to Late, Middle Touronian- Late Touronian- Coniacian to Early Santonian are younger equivalents of this section which can be equaled to Surgah Formation. According to Biozone divisions, this unit is equivalent to Biozone No. 28 presented by Wynd (1965) and also based on Dunham classification, the unit is packestone and partly boundstone. The lower Contact of the unit is Concordant and Continuous with glauconitic sandy limestone and its upper Contact is Continuous and Concordant with marl and interbeddings of Limestones dating back to Santonian- Campanian. By comparing Bahar Section with South eastern Lorestan section (Poshte jangal anticline), (Azadbakht, 2015), the following results were obtained: From Litho/bio stratigraphical view, thick to thin-bedded Limestones (Light to dark gray) interbedded with marl in Poshte jangal anticline are Correlated with Inoceramus limestone and marly Limestone interbedded with marl in Bahar Section. They are dated back to EarlyTuronian to Early Campanian.Due to Strong similarity of Lithostratigraphy and biostratigraphy between Bahar section located in Southern Esfahan (Central Iran) and section of Poshte jangal anticline located in Southeast of Lorestan, it can be deducted that a branch of Lorestan Sea has advanced in Turonian- Coniacian times and some parts of Southern Esfahan has been covered by the sea.
