• فهرس المقالات Early Cretaceous

      • حرية الوصول المقاله

        1 - Biostratigraphy and microfacies analysis of Gadvan Formation (late Barremian-early Aptian) in Coastal Fars zone, (Zagros, SW Iran)
        Alireza Abtahian Massih Afghah Vahid Ahamadi
        The investigation of lithostratigraphy, biostratigraphy and the microfacies analysis of the Gadvan Formation as an oil reservoir of Lower Cretaceous in the Zagros Basin is crucial. In this study Naser Abad section (Coastal Fars region, SW of Iran), consists of 170 meter أکثر
        The investigation of lithostratigraphy, biostratigraphy and the microfacies analysis of the Gadvan Formation as an oil reservoir of Lower Cretaceous in the Zagros Basin is crucial. In this study Naser Abad section (Coastal Fars region, SW of Iran), consists of 170 meters thin to medium-bedded limestone with interbeds shale and marly limestone. According to stratigraphic distribution of identified foraminifers, two biozones are established which are: Paleorbitolina lenticularis zone and Hedbergella infracretacea Zone. Based on the investigated faunal assemblage, the age of Gadvan Formation is assigned to late Barremian-early Aptian. Microfacies studies led to the identification of five microfacies types which include: Algal-intraclast- bioclast wackestone, Intraclast- bioclast wackestone, Planktonic- bioclast wackestone, Radiolarian packstone and Orbitolina- bioclast wackestone. These microfacies show that the Gadvan Formation was deposited in both shallow water ramp and hemipelagic paleoenvironments. According to microfacies, carbonate platform of Gadvan Formation in the studied area corresponds to a moclinal platform which was affected by basement of Kazerun Fault zone. تفاصيل المقالة
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        2 - Depositional History and Sequence Stratigraphy of the Tirgan Formation (Barremian – Aptian) in the Zavin section, NE Iran
        M. Javanbakht R. Moussavi Harami A. Mahboubi
        The Tirgan Formation (Barremian – Aptian) is exposed in the Kopet Dagh in northeast Iran. One stratigraphic section in Zavin was measured with a thickness of 110 meters. This Formation in section consists of three parts (including lower carbonate, limy shale &ndas أکثر
        The Tirgan Formation (Barremian – Aptian) is exposed in the Kopet Dagh in northeast Iran. One stratigraphic section in Zavin was measured with a thickness of 110 meters. This Formation in section consists of three parts (including lower carbonate, limy shale – marl and upper carbonate rocks). Based on the study of 94 thin sections, 10 carbonate and 2 siliciclastic lithofacies have been identified. Carbonate lithofacies were deposited in a ramp platform in fore-shoal, shoal, lagoon and tidal flat environments. Sea level changes during the early Cretaceous time led to the formation of different large scale depositional sequences Zavin (two). The present data can help in the reconstruction of the tectonic history of the area during early Cretaceous time. تفاصيل المقالة