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) ...
Read More
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.
R. Mirzaee Mahmoodabadi; Y. Lasemi; M. Afghah
Abstract
Shaley Pabdeh Formation (Paleocene-Oligomiocene) expanded in Fars, Khozestan and Lorestan. Lower Lithostratigraphical limit with Gurpi Formation recognized by purple shale. Upper Lithostratigraphical limith with Asmari Formation is transitional. In order to study sedimentary environments and sequence ...
Read More
Shaley Pabdeh Formation (Paleocene-Oligomiocene) expanded in Fars, Khozestan and Lorestan. Lower Lithostratigraphical limit with Gurpi Formation recognized by purple shale. Upper Lithostratigraphical limith with Asmari Formation is transitional. In order to study sedimentary environments and sequence stratigraphy of Pabdeh Formation two stratigraphic sections were chosen (Zanjiran and Shahneshin). Petrographic study indicated 9 pelagic and calciturbidite microfacies. These microfacies in deep marine deposited. Calciturbidite facies were formed during sea level highstand, when high rate of carbonate production result in transportation of carbonate sediment in deep sea. Sequence stratigraphy study shows that Pabdeh Formation consists of two depositional sequences. In Zanjiran section lower and upper contact of first sequence is type two and upper contact of second depositional sequence is conformity with unconformity. In Shahneshin section the lower contact is type two and upper contact is correlative conformity with unconformity.
Kh. Khosrotehrani; M. Afghah; V. Ahmadi
Abstract
In this research, two stratigraphic sections were chosen from the late Paleocene to early Miocene (Jahrum and Asmari Formations). These sections includes Sadra and Dodaj plus 645 meters of late Paleocene to early Miocene scdiments. For this investigation 360 thin sections were prepared and 12 samples ...
Read More
In this research, two stratigraphic sections were chosen from the late Paleocene to early Miocene (Jahrum and Asmari Formations). These sections includes Sadra and Dodaj plus 645 meters of late Paleocene to early Miocene scdiments. For this investigation 360 thin sections were prepared and 12 samples analysed by XRF. We studied Biotope that includes biozone. These index biozones and percentage of elements that appears in biotope are identified. Principally index foraminifers, identified in the studied sections, are listed bellow: Miscellanea sp. Kathina sp., Fallotella alavensis Mangin, Opertorbitionlites sp. Alveolina sp. Lituonella ruberti Stache, Rhapydionina urensis Sirel, Orbitolites complanatus Lamark, somalina Stefaninii Silvestri, Dictyoconus sp. Coskinolina liburnica Atache., Nummulites fabianii Prever, Silvestriella tetraedra Gumbel., Nummulites fichteli Michelotti, Austrotrillina howchini Schlumberger, Meandropsina anahensis Henson.
Regarding the frequency, type of wall and biotope percentage ratio of each foraminiferal biozone, there are different biotopes that indicate change in the trend of paleoecologic conditions of the late Paleocene to Oligocene sediments.
