Stratigraphy and Palaeontology
Mir Amir Salahi; Abbas Ghaderi; Alireza Ashouri; Ali asghar siabghodsi
Abstract
To separate the different units of the Paleogene sequences of the Kopet-Dagh basin and their regional correlation with the adjacent areas in the Central Asia, the Oyster bivalves fossils are used in the current research. Also, the study of their paleobiogeography has been considered in this study. Based ...
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To separate the different units of the Paleogene sequences of the Kopet-Dagh basin and their regional correlation with the adjacent areas in the Central Asia, the Oyster bivalves fossils are used in the current research. Also, the study of their paleobiogeography has been considered in this study. Based on this fauna, Pycnodonte-Oestra community in the Chehelkaman Formation uppermost parts represents the late Paleocene age and the first occurrence of Flemingostrea hemiglobosa at the base of the Khangiran Formation confirms the beginning of Eocene epoch. Association of different species and subspecies of Turkostrea in the Khangiran Formation demonstrates the middle part of early Eocene and Sokolowia community near the top of the Khangiran Formation shows the Lotetian-Bartonin ages. These features are in full compliance with the bivalve communities recorded from the other parts of Central Asia such as Amu-Darya, Farghana, Afghan - Tajik and Trim basin of China. It illustrates the same geological history of the mentioned areas during Paleogene, indicates the occurrence of different types of molluscan taxa in the Kopet-Dagh basin is the same as parallel horizons and equivalent time units throughout the extensive Central Asian region.
Stratigraphy and Palaeontology
Meysam Shafiee Ardestani; Mohammad Vahidinia
Abstract
Apertural protective structures of the planktonic foraminifera in the Abderaz Formation have been studied in order to determine seal level changes in 4 stratigraphical sections including: Abderaz village, Muzduran pass, Padeha village and Shorb . Lithological study of the Abderaz Formation shown that ...
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Apertural protective structures of the planktonic foraminifera in the Abderaz Formation have been studied in order to determine seal level changes in 4 stratigraphical sections including: Abderaz village, Muzduran pass, Padeha village and Shorb . Lithological study of the Abderaz Formation shown that Shorab section (east of the kopeh-Dagh basin) with 374 meters and Padeha village section with 602 meters represent minimum and maxiumum thickness, respectively. A total of 77 planktonic foraminifers species belonging to 19 genera, have been identified in studied sections. Eight Apertural protected plates have been recognized in the umbilical side of the distinguished planktonic foraminifera. Besides, 4 porticus structures (Simple lip, Tooth like-Porticus, Spiral Porticus, Imbricate Porticus) belonging to the morphotype 2 and 3, three Tegillum structures (Roll-type Tegillum, Strap-Shape Tegillum, Sheet like-Tegillum) belonging to the morphotype 3, and one Lip structure belonging to the morphotype 1, as well as their frequency have been recognized. Statistical analysis of protected structures of the umbilical area have been demonstrated that unlike to the imbricate porticus and sheet like Tegillum, the lip and simple lip structures show the highest frequency, indicating that the Abderaz Formation deposited in the relative shallow marine environment.
A Gholami fard; A Kani; A Mahanipour
Abstract
This study investigates the Lower Cretaceous sedimentary succession comprising Sarcheshmeh Formation and Sanganeh Formation in the Ghaleh zoo Section from the standpoint of Calcareous Nannofossils. The results reveals presence of 60 species from 33 genera of 15 families. Based on the index nannofossil ...
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This study investigates the Lower Cretaceous sedimentary succession comprising Sarcheshmeh Formation and Sanganeh Formation in the Ghaleh zoo Section from the standpoint of Calcareous Nannofossils. The results reveals presence of 60 species from 33 genera of 15 families. Based on the index nannofossil taxa, the upper part of NC6, NC7A, NC7(B&C) and NC8(A&B) nannofossil zones (equivalent to the upper part of of CC7a, CC7b and CC8 zones), are present in this section. The calcareous nannofossils found in this section point to an Early Aptian to Late Aptian age of deposition for the rocks of Sarcheshmeh Formation and Late Aptian to Early Albian for the rocks of Sanganeh Formation.
F Foroughi; A Lotfali Kani; S Gardin; M Vahidinia
Abstract
The Kopet-Dagh basin is located in the northeast of Iran, in the triangle border of Iran, Turkmenistan and Afghanistan and consists of the marine Jurassic to Neogene strata. The Abtalkh Formation is one of the thickest lithostratigraphic upper Cretaceous units in the eastern Kopet-Dagh basin and is composed ...
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The Kopet-Dagh basin is located in the northeast of Iran, in the triangle border of Iran, Turkmenistan and Afghanistan and consists of the marine Jurassic to Neogene strata. The Abtalkh Formation is one of the thickest lithostratigraphic upper Cretaceous units in the eastern Kopet-Dagh basin and is composed of light gray, green to bluish marl and silty marl. The Abtalkh Formation conformably overlies the Abderaz Formation, which contains marls and chalky limestones and is conformably overlain by the Nayzar Formation, which consists of sandstone, silty marl and limestone. The Abtalkh Formation contains very aboundant, rich and good to moderately preserved calcareous nannofossil assemblages of Tethyan realm. The total 220 samples in the jalilabad and 467 samples in the AbtalkhVillage stratigraphic sections, representing the oldest and youngest strata of upper Abderaz, Abtalkh and base of Nayzar successions, were collected. The thickness of Abtalkh Formation in the Jalilabad stratigraphic section is 1325.8m and for the AbtalkhVillage stratigraphic section is 1765m. One hundred sixteen nannoplanktonic species belonging to forty three genera and fifteen families were identified. The biostratigraphic study allowed the recognition of the calcareous nannofossil biozones of Sissingh (1977) emended by Perch-Nielsen (1985) and Burnett (1998). From bottom to top, part of CC19, CC20, CC21, CC22, part of CC23a biozones and UC14dTP, UC15bTP, UC15cTP, UC15dTP subzones and UC16 biozone were identified in the Jalilabad section. The Abtalkh Village section in the middle of eastern Kopet-Dagh basin is started with CC20 (UC15bTP) biozone and continued to CC23a (UC16) biozone. Nearly more than 30 calcareous nannofossil species were reported for the first time in Iran. The results of this study indicated that the age of Abtalkh Formation spans from early to uppermost Late Campanian for these two sections in the Kopet-Dagh basin.
M. R. Poursoltani; R. Moussavi Harami; Y. Lasemi
Abstract
The KopetDaghBasin of northeast Iran formed in the NeotethysOcean after the closure of Paleotethys in the south of Turan plate. A thick sequence of Jurassic to Miocene sediments has been deposited in this basin without any major break. The siliciclastic Kashafrud Formation ...
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The KopetDaghBasin of northeast Iran formed in the NeotethysOcean after the closure of Paleotethys in the south of Turan plate. A thick sequence of Jurassic to Miocene sediments has been deposited in this basin without any major break. The siliciclastic Kashafrud Formation (Middle Jurassic), overlying unconformably on Triassic rocks and ultrabasic rocks comprises nearly 2 km of turbidite and fluvio-deltaic facies, consists of sandstone, shale and conglomerate. Trace-fossil assemblages are presented in some units with different environments. The most important ichnofossils in this formation are Skolithos, Palaeophycus tabularizes,Belerhaphe, Thalassinoides suevicus, Psilonichnus , Planololites beverleyensis, Rhizocoralium jenese, Scolicia, Conichnus, Lophactenium, Palaeophycus striatus,Taenidium. It is interpreted, based on identified ichnofossils, the Kashafrud Formation may have been deposited in fluvio-deltaic and deep water (turbidity conditions) environment. We hope that these data can help in a better understanding of palaeogeography and tectonic setting of the region during Middle Jurassic.
