Stratigraphy and Palaeontology
Behzad Saeedi Razavi; mozhgan rikhtehgarzadeh; saeedeh senemari
Abstract
In order to study the biostratigraphy of Sarvak and Ilam in wells A1 and A2 of Binak oilfield, B of Gachsaran oilfield, C of Aghajari oilfield and D of Rag-Sefid oilfield, numerous thin sections have been studied microscopically In the biostratigraphic study of 5 biozones in the Sarvak and Ilam formations, ...
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In order to study the biostratigraphy of Sarvak and Ilam in wells A1 and A2 of Binak oilfield, B of Gachsaran oilfield, C of Aghajari oilfield and D of Rag-Sefid oilfield, numerous thin sections have been studied microscopically In the biostratigraphic study of 5 biozones in the Sarvak and Ilam formations, the following fields were introduced: 1-Oligostegina flood zone, 2- Nezzazata – Alveolinids assemblage zone, 3- Rudist debris zone, 4 -Nezzazatinella – Dicyclina assemblage zone, 5- Rotalia skourensis – algae assemblage zone and Oligostegina food zone. Based on the study of age of Sarvak Formation from Late Albian to Turonian, and for Ilam Formation from Coniasian to Santonian. Based on the biostratigraphy correlation and thickness analysis of biozones introduced in the two studied formations, the depth of the Zagros basin from northwest to southeast decreases dramatically.
L Bakhshandeh; T Mohtat; H Bakhshandeh; S Senmari
Abstract
The Ilam Formation, cropping out in the ZagrosMountain, consists of 195m of cream-colored limestones in the type section, south of Ilam city. This formation has conformable and continuous contacts with the lower Surgah and the upper Gurpi formations. In the present study, 35 foraminifera planktonic species ...
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The Ilam Formation, cropping out in the ZagrosMountain, consists of 195m of cream-colored limestones in the type section, south of Ilam city. This formation has conformable and continuous contacts with the lower Surgah and the upper Gurpi formations. In the present study, 35 foraminifera planktonic species of 17 genus have been identified. The Ilam formation was divided into 4 cosmopolitan biozones on the basis of the planktonic foraminifera which, consist of: Biozone 1-Marginotruncana sigali -Dicarinella primitiva Partial Zone, Biozone 2- Dicarinella concavata Interval Zone, Biozone 3- Dicarinella asymetrica Total -range zone, and Biozone 4- Globotruncanita elevata Partial- range zone. According to these biozones, the Ilam formation was deposited from the late middle Turonian to the early Campanian.
S.H. Vaziri; D. Jahani; M. Safdari; F. Chegeni
Abstract
The Ilam Formation in southwestern Khorram Abad with a thickness of up to 204 meters consists of uniform limestones with Middle Turonian to Early Campanian age which were deposited in a continuous sedimentation process. In this section, the Ilam Formation has continuous ...
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The Ilam Formation in southwestern Khorram Abad with a thickness of up to 204 meters consists of uniform limestones with Middle Turonian to Early Campanian age which were deposited in a continuous sedimentation process. In this section, the Ilam Formation has continuous and transitional contacts with the Sourgah Formation in the lower boundary and the Gurpi Formation in the upper boundary. In the present study, 9 genera, 30 species and 2 biozones of the planktonic foraminifera have been recognized. The Ilam Formation in the studied section consists of a shaly facies and three carbonatic microfacies include mudstone, wackestone and packstone containing planktonic foraminifera. Shaly facies and mentioned microfacies were deposited in deep-open marine, which formed in a quiet environmental condition and increased environmental energy in microfacies with mudstone texture toward microfacies with wackestone and packstone textures. Whereas in the studied section recognized microfacies are not related to parts of continental shelf,such as ; bar, lagoon and tidal flat, therefore it could be said that, the studied area was part of profound depositional basin in Middle Turonian to Early Campanian.
