Biostratigraphy, Paleobathymetry, and identification of new planktonic foraminiferal species of the Abderaz Formation at Qalezo section, west of the Kopeh-Dagh sedimentary basin
Subject Areas : Geoscience Fields in relation with Petroleum Geologyمیثم شفیعی اردستانی 1 , محمد وحیدی نیا 2 , فاطمه فرازی فر 3
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Abstract :
In this study, Abderaz Formation at Qalezo section in the west of the Kopeh-Dagh sedimentary basin has been studied. It has consisted mainly of massive limestone, Marl and chalky limestone units at the mentioned section. Abderaz Formation at Qalezo section, the lower contact with Aitamir Formation is paraconform and the upper contact with Abtalkh Formation is conformed and continuous. The thickness of Abderaz Formation, 216 meters, has been measured. In this investigation have been identified 55 planktonic foraminifera species belong to 15 genera, in a frame of 4 biozones have been recognized. Finally, based on this research was distinguished from latest Early Turonian-Late Santonian ages for this section. In this study four planktonic foraminifera species, Dicarinella bouldinensis (Pessagno 1967), Dicarinella takayanagii Hasegawa 1999, Marginotruncana desioi (Gandolfi 1955), Marginotruncana caronae Peryt 1980 have been introduced for the first time in Iran. Also in this research planktonic foraminifera test geometric in Abderaz Formation at Qalezo section has been studied for sea-level changes. In Lower-Middle Turonian substages, the high frequency of the M1 group and low frequency of M3 group displayed fall seal level at this time. In Late Turonian frequencies of M3 group with accompany of %P was shown rise sea level. In the Coniacian and Santonian stages, the M1 group is dominant and the M3 group is low frequency and all of the mentioned evidence were demonstrates fall sea level. Also, the depth average of the studied section based on Depth = e (3.58718 + (0.03534 × %P)) has been calculating 146 meters which were shown these sediments deposited in Outer Neritic environment.
