Stratigraphy and Palaeontology
Mohammad Sharifi; Ebrahim Ghasemi-Nejad; M. Akhtari; Mehdi Sarfi; Mohsen Yazdi-Moghadam
Abstract
The Bazyab Formation is one of the Cretaceous rock units in the Khor and Byabanak area. In this study we investigated palynological content of the Bazyab Formation at the Bazyab stratigraphic section where it is up to 1067 meters thick and consists of marlstones, shales, sandstones, limestones and sandy ...
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The Bazyab Formation is one of the Cretaceous rock units in the Khor and Byabanak area. In this study we investigated palynological content of the Bazyab Formation at the Bazyab stratigraphic section where it is up to 1067 meters thick and consists of marlstones, shales, sandstones, limestones and sandy limestones, claystone, shale and interlayers of limestone. The formation at this section is confined conformably between Shah-Kuh Formation at the base and Debarsu Formation at the top. A total of 40 rock samples have been collected from the formation and investigated for their palynological contents. The obtained palynological data resulted in detection of twenty-nine genera and54 species of marine dinocysts alongside with 20 genera and 29 species of terrestrial palynomorphs (spores and pollens). An age of Aptian –Albian is constrained for the formation in this section on the evidence of recorded palynomorphs. Based on high frequencyof inner neritic dinocysts, planktonic foraminifers and mudstone and wackestone facies of the carbonate beds, an inner shelf sedimentary environment was suggested as the depositional environment of the Bazyab Formation.
Sh. Nouri; E. Ghaseminejad; M. R. Majidifard
Abstract
The Sanganeh Formation is one of the Early Cretaceous rock units in the Koppeh- Dagh basin. This formation in the Dahaneh Gholaman section (in north of Bojnord city) with a thickness of 900 meters (consist of marl, shale and limestone) is laying conformably on the Sarcheshmeh Formation and covered by ...
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The Sanganeh Formation is one of the Early Cretaceous rock units in the Koppeh- Dagh basin. This formation in the Dahaneh Gholaman section (in north of Bojnord city) with a thickness of 900 meters (consist of marl, shale and limestone) is laying conformably on the Sarcheshmeh Formation and covered by Atamir Formation. In this study, biostratigraphic investigations on 50 palynological samples from the Sanganeh Formation led to recognition of 21 genera and 31 species of dinoflagellate cysts indicating an age of Late Aptian-Albian belonging to Odontochitina operculata zone. Also palynofacies studies revealed two types of palynofacies (II and IV). Palynofacies studies show dominance of palynofacies II through the stratigraphic column indicating a marginal dysoxic-anoxic basin. On the other hand, presence of palynofacies IV in some parts along the stratigraphic column reflects increase in the depth of the marine environment from time to time.
