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Open Journal of Geology 2017年第5期7卷 666-682页

作者： Mohammad Medadi Hossein Mosaddegh Seyed Mohsen Aleali mahmoud reza majidifard Department of Geology Science and Research Branch Islamic Azad University Tehran Iran Department of Geology Faculty of Earth Sciences Kharazmi University of Tehran Iran Department of Geology Science and Research Branch Islamic Azad University Tehran Iran Research Institute for Earth Sciences in Geological Survey of Iran Tehran Iran

Species richness of foraminifera assemblages in the Permian succession, contains Dorud, Ruteh and Nessen Formations, in Central Alborz—North of Iran, was estimated and studied based on lithostratigraphy and microbiostratigraphy of Permian. We used four non-parametric estimators to investigate the species richness: Chao 2, Jackknife 1, Jackknife 2 and bootstrap. These methods estimates the species richness based on the presence/absence data of each taxon identified in the samples. We use the submenu of quadrat richness in “Past” [1] software to estimate richness in regional chronostratigraphic *** results show that the estimated diversity of foraminiferal assemblages with the exception of late Yakhtashian, increased constantly from Asselian to Murgabian with the highest diversity of foraminifera seen in the Murgabian. The main decrease in foraminiferal species richness happened during the Midian which corresponds to the kamura cooling event.

关键词： Permian Foraminifera Species Richness Central Alborz Western Tethys

Reineckeiidae (Ammonoidae) Family of the Dalichai Formation in Damghan Area (East Alborz), Iran

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Open Journal of Geology 2017年第6期7卷 888-914页

作者： Marjan Zadesmaeil mahmoud reza majidifard Seyed Hamid Vaziri Davood Jahani Departmant of Geology North Tehran Branch Islamic Azad University Tehran Iran Research Institute for Earth Sciences Geological Survey of Iran Tehran Iran

The present study is concerning the systematic descriptions of the Middle Jurassic (Callovian) ammonite fauna from the Damghan Area (eastern Alborz) and contains a rather rich ammonite fauna. The described ammonites come from the Middle part of the Dalichai Formation, consisting of an alternation of green marl, grey limestone and marly limestone. In this research, the biostratigraphy of these rocks is discussed with special emphasis on the abundant ammonite fauna (Reineckeiidae family). Altogether, 74 specimens of ammonites belonging to 14 species, 3 genera, 3 sub genera from Reineckeiidae family are described. Palaeobiogeographically the ammonite fauna is closely related to that of the sub-Mediterranean Province of the northwestern Tethys. The ammonites represent four zones, i.e. Rehmannia (Loczyceras) cf. segestena (Anceps Zone), Rehmannia (Loczyceras) reissi (Anceps Zone), Rehmannia (Loczyceras) rehmanni (Anceps Zone), Rehmannia (Loczyceras) sequanica densicostata (Coronatum Zone), Reineckeia (Tyrannites) convexa (Gracilis Zone), Reineckeia (Tyrannites) pictava (Gracilis Zone), Reineckeia (Reineckeia) anceps anceps (Anceps Zone), Reineckeia (Reineckeia) anceps elmii (Anceps Zone), Reineckeia (Reineckeia) cf. fehlmani (Anceps Zone), Reineckeia (Reineckeia) nodosa (Athleta Zone), Collotia cf. multicostat (Anceps Zone), Collotia cf. gaillardi (Coronatum Zone), Collotia cf. oxyptychoides (Athleta Zone), Collotia cf. collotiformis (Athleta Zone).

关键词： Jurassic Reineckeiidae Palaeobiogeographically Dalichai Formation Alborz

Facies Interpretation, Depositional Environment and Sequence Stratigraphy of the Gachal Formation in the Madbeiki Section, Kalmard Block, East Central Iran

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Open Journal of Geology 2016年第6期6卷 439-458页

作者： Soheil Erfani Mohammad Hossein Adabi Mahmood reza majidifard Nader Kohansal Ghadimvand Department of Geology North-Tehran Branch Islamic Azad University Tehran Iran Department of Geology Faculty of Earth Sciences Shahid Beheshti University Tehran Iran Research Institute for Earth Sciences Geological Survery of Iran Tehran Iran Department of Geology Islamic Azad University North-Tehran Branch Tehran Iran

Deposits of Lower Carboniferous rocks in Kalmard block are recognized by Gachal informal formation, showing various characteristics in different outcrops. Lower Carboniferous deposits (Gachal formation) are composed chiefly of carbonate, evaporite and siliciclastic rocks. This formation is composed of 198 m sandstone, limestone and dolomite as well as a small amount of shale, marl and gypsum in the Madbeiki section. This formation unconformably underlies Precambrian metamorphic deposits (Kalmard formation) while lateritic soils of lower Permian (Chili formation) are depicted overlying an erosional unconformity above this formation. According to lithologic and microscopic investigations, the deposits of Gachal formation can be divided into 1 siliciclastic petrofacies, 1 evaporite microfacies and 16 carbonate microfacies. Field observations, along with microscopic examinations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the rocks of the studied formation. Vertical changes of microfacies and depth variation curve indicate the high thickness of the microfacies of tidal flat, lagoon and shoal environments and low thickness of the microfacies of open marine environment. The carbonate-evaporite-siliciclastic sequence of Gachal formation is made up of three third-order depositional sequence, separated each other by type 1 sequence boundary (SB1). Siliciclastic and evaporite deposits include LST system tract, and carbonate microfacies involve TST and HST system tracts, separated from each other by MFS. Gachal formation rocks in Madbeiki section are deposited in a low-angle homoclinal ramp, mostly in the inner ramp, located in the southern Paleotethys Ocean. The depositional sequence identified in Gachal formation points to the age of Lower Carboniferous, conforming to upper Kaskaskia super sequence. The upper erosional boundary between Gachal and Chili formations conform to the global-scale sea level fall.

关键词： Lower Carboniferous Kalmard Block Gachal Formation Depositional Environment Sequence Stratigraphy

Sequence Stratigraphy of Lower Carboniferous Rocks in Bakhshi Section, East-Central Iran

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Open Journal of Geology 2017年第2期7卷 200-211页

作者： Soheil Erfani Mohammad Hossein Adabi Mahmood reza majidifard Nader Kohansalghadimvand Bibihaniyeh Emraninasab Department of Geology Islamic Azad University North Tehran Branch Tehran Iran Department of Earth Sciences Shahid Beheshti University Tehran Iran Research Institute for Earth Sciences Geology Survey of Iran Tehran Iran

The deposits of Lower Carboniferous rocks in Kalmard Block are characterized by Gachal informal formation, showing various properties in different outcrops. These deposits (in Gachal formation) are composed chiefly of carbonate, evaporite and siliciclastic rocks. This formation commonly hosts 190 m sandstone, limestone, dolomitic limestone and dolomite as well as a small amount of shale and marl in the Bakhshi section. It unconformably underlies Devonian deposits (Rahdar formation) while lateritic soils of lower Permian (Chili formation) are depicted overlying an erosional unconformity above this formation. The mixed carbonate-evaporite-siliciclastic sequence of Gachal formation is made up of three third-order depositional sequences, separated from each other by Type 1 sequence boundary (SB1). Siliciclastic and evaporite deposits include LST system tract, whereas carbonate microfacies involve TST and HST system tracts, separated from each other by MFS. The depositional sequences identified in Gachal formation point to the Lower Carboniferous age, conforming to upper Kaskaskia supersequence. The upper erosional boundary between Gachal and Chili formations complies with the global-scale sea level fall.

关键词： Lower Carboniferous Kalmard Block Gachal Formation Sequence Stratigraphy

Facies Analysis and Depositional Environment of Upper Permian Rocks in Darin Section, East-Central Iran

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Open Journal of Geology 2017年第3期7卷 242-256页

作者： Bibi Haniyeh Emraninasab Mohammad Hossein Adabi Mahmood reza majidifard Nader Kohansal Ghadimvand Sohei Erfani Department of Geology Islamic Azad University North Tehran Branch Tehran Iran Department of Earth sciences Shahid Beheshti University Tehran Iran Research Institute for Earth Sciences Geology Survey of Iran Tehran Iran

Deposits of Permian rocks in Kalmard Block are recognized with Khan Group, showing various characteristics in different outcrops. This group is made up of three informal formations, namely Chili, Sartakht and Hermez. Upper Permian deposits (Hermez Formation) are composed chiefly of lateritic and carbonate rocks. This formation is composed of 65.5 m lateritic soils, lateritic sandstone, limestone, dolomite and dolomitic limestone in the Darin section. This formation unconformably overlies middle Permian siliciclastic and evaporite deposits (Sartakht Formation), where as it is depicted underlying an erosional unconformity above lateritic deposits of lower Triassic (Sorkh Shale Formation). According to lithologic and microscopic investigations, the deposits of Hermez Formation can be divided into 1 siliciclastic petrofacies and 14 carbonate microfacies. Field observations, along with microscopic examinations, have resulted in identifying tidal flat, lagoon, shoal and open marine environments in the rocks of the studied formation. Vertical changes of microfacies and depth variation curve point to the high thickness of the microfacies of lagoon, tidal flat and shoal environments and low thickness of open marine microfacies. Hermez Formation rocks in Darin section are deposited in a low-angle homoclinal ramp, mostly in the inner ramp, located in the southern Paleo-Tethys Ocean.

关键词： Upper Permian Kalmard Block Hermez Formation Depositional Environment