Stratigraphy and Palaeontology
Mahin mohamadi; R. Shabanian; H. M. Alizadeh
Abstract
This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field ...
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This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field study and lithological diversity 8 lithic zone have been investigated. 102 samples have been picked up systematically from this sequence. This study lead to determining 41 species from 15 genera of planktonic foraminifera.The systematic and classification of fauna are based on The (Postuma 1971) , (Caron1985) , (Loeblich and Tappan 1988) and (Permoli Silva And Verga 2004). .Based on their range chart the bio zonation model for this deposit with 9 Bio Zones as bellow have been suggested and have compared with cretaceous global standard bio zones (Robazynsky and Caron 1985) and (Permoli Silva and Verga, 2004) Dicarinella concavata Interval Zone (Robazynsky and Caron, 1995) Dicarinella asymetrica Total range Zone(Robazynsky and Caron, 1995) Globotruncanita elevata IntervalrangeZone(Robazynsky and Caron, 1995) Globotruncana ventricosa IntervalZone (Robazynsky and Caron, 1995) Rodotruncana calcarata Total range Zone(Robazynsky and Caron, 1995) Globotruncanella havnensis Partial Range Zone (Robaszynski and Caron, 1985) Globotruncana aegyptiaca Interval Zone (Robazynsky and Caron, 1995) Gansserina gansseri Interval Zone (Robazynsky and Caron, 1995) Abathamphalus mayaroensis Total range Zone(Robazynsky and Caron, 1995) The suggested age for th.is sequence based on planktonic foraminifera is upper coniantian to upper Maestrichtian and belong to deep shelf area . Based on the morphology of planktonic foraminifera and their keei we suggest deep sea environment for these deposits.
M. mohamadi; M. Yazdi
Abstract
There are many precious microremains of chondrichtyans (cartilage fishes) in calcareous beds of Geirud Formation. These micro remains consist of teeth, branchial denticles and sales species and genus of the family and subfamily: Phoebodontidae, Protacrodontoidea, HybodontoideaandCtenacanthoidea. Geirud ...
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There are many precious microremains of chondrichtyans (cartilage fishes) in calcareous beds of Geirud Formation. These micro remains consist of teeth, branchial denticles and sales species and genus of the family and subfamily: Phoebodontidae, Protacrodontoidea, HybodontoideaandCtenacanthoidea. Geirud Formation consists of alternating silisiclastics and calcareous beds with 1-2 basaltic units well distributed in Central Alborz. The upper Devonian/Lower carboniferous age assigned to Geirud Formation. The name of the Formation has been driven from type locality – Geirud village in north of Tehran. The upper Devonian/Lower carboniferous deposits have been studied along Alborz Mountain range and Central Iran. Faunal similarity between Famennian deposits of Central Iran and Eastern Alborz with Geirud Formation (Hairapetian & Klug 2002) confirm the basin relationship between these areas, also faunal relationship between these fauna and the fauna of Famennian in Morocco and Algeria confirm that these deposits belong to shelves of North Gondwanaland (Ginter & al., 2002). These fauna are associated with conodonts of expansa zone.