Iranian Journal of Earth Sciences
,
Issue5,Year,
Autumn
2022
This study provides a evaluation of the initial carbonate mineralogy, and diagenetic condition of the Ruteh Formation, a middle-late Permian carbonate sequence, in the Emarat section in Central Alborz, northern Iran. 200 samples were examined for petrographical contents More
This study provides a evaluation of the initial carbonate mineralogy, and diagenetic condition of the Ruteh Formation, a middle-late Permian carbonate sequence, in the Emarat section in Central Alborz, northern Iran. 200 samples were examined for petrographical contents and thirty-four samples were collected for geochemical analysis. The high Sr and Na contents, Sr/Na>1, and the presence of dolomites and dissolution fractures are indicative aragonite early mineralogy. The diagenetic process in the Ruteh Fm. are an indication of the marine, meteoric and burial diagenetic environments. The original carbonate texture in the Ruteh Fm. are Severely affected by diagenetic process. The data obtained from the values of the Major (Ca and Mg), minor (Sr, Na, Fe, and Mn), oxygen and carbone isotopes show the initial aragonite composition of the Ruteh Fm. deposited in a subtropical shallow water. An open diagenetic system was indicated by changes in the values of Sr / Ca and δ18O vs. Mn. The shallow burial diagenetic temperature of the Ruteh carbonate was approximate 28.6°C with the maximum diagenetic temperature of 53.4°C.
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Iranian Journal of Earth Sciences
,
Issue4,Year,
Summer
2022
Seven genera and seventeen species of marine Ostracoda are reported for the first time from the Attari section (Qom Formation), northeast of the Semnan, Central Iran. In this section, the Qom Formation outcrops with 280 m thickness lies on the Eocene volcanic and under More
Seven genera and seventeen species of marine Ostracoda are reported for the first time from the Attari section (Qom Formation), northeast of the Semnan, Central Iran. In this section, the Qom Formation outcrops with 280 m thickness lies on the Eocene volcanic and under the Upper Red formation. According to the distribution of index foraminifera, there is conspicuous similarity between larger bentic foraminifera assemblages of the Qom Formation foraminifera and those of the Zagros basin, such as Borelis melo curdica the age of Qom Formation in the Attari section is Early Miocene (Burdigalian). The Miocene and even Oligocene Ostracoda fauna, relatively similar to the Attari section, have been reported from the Mediterranean area and the Proto- Indo- Pacific Ocean. The presence of one species with Paratethian origin in the Qom Formation is strong evidence that during the Burdigalian stage, the sea way between Central Iran and Paratethys basin still existed.
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Iranian Journal of Earth Sciences
,
Issue4,Year,
Summer
2023
The Burdigalian carbonate of the Central Iran contains very well-preserved specimens of Kuphus polythalamius. The tube of Kuphus polythalamius is a calcareous secretion that enables Pelecypoda to live in the mud of shallow seas. This research focusses on the Paleontolog More
The Burdigalian carbonate of the Central Iran contains very well-preserved specimens of Kuphus polythalamius. The tube of Kuphus polythalamius is a calcareous secretion that enables Pelecypoda to live in the mud of shallow seas. This research focusses on the Paleontology and taphonomy of the Kuphus polythalamius of the Member F (Qom Formation) in the southeast of Kashan located in the Central Iran. The Member F is 60 meters thick and composed of medium bedded limestone. The scattering of the larger benthic foraminifera in the study area indicates the existence of the Borelis melo curdica-Borelis melo melo assemblage zone of Burdigalian age. The presence of Kuphus polythalamius among the porcelaneous foraminiferal and green algal assemblage demonstrate that carbonate generation happened in warm tropical to subtropical marine. The surface of some samples contains distinct horizons of beekite, indicating a break in sedimentation, which is expanded as a silica crust on carbonate tubes.
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Iranian Journal of Earth Sciences
,
Issue4,Year,
Summer
2023
The benthic and planktonic foraminiferal contents of the Bangestan Group (Sarvak, Surgah and Ilam formations) in the Sepid Kuh anticline in the Lorestan Zone, W Iran, were studied. Bangestan Group consists of limestone, argillaceous limestone, dolomitic limestone and ma More
The benthic and planktonic foraminiferal contents of the Bangestan Group (Sarvak, Surgah and Ilam formations) in the Sepid Kuh anticline in the Lorestan Zone, W Iran, were studied. Bangestan Group consists of limestone, argillaceous limestone, dolomitic limestone and marl with thickness of 5400 m. In this section Bangestan Group overlies Garu Formation disconformably and its upper boundary is not exposed. By micropaleontological study on 176 thin sections, 8 genus and 34 species planktonic foraminifera were identified. 400 m of Sarvak Formation has very little fossil diversity that does not indicate a certain age. For this reason, this interval was called the indeterminate zone, which due to its stratigraphic position, is probably of Cenomanian age. Based on the biostratigraphical range of planktonic foraminifera distinguished, four biozones can be identified: Helvetoglobotruncana helvetica Total Rang Zone (Early- Middle Turonian), Marginotruncana schneegansi partial Range Zone (late Turonian), Diacarinella concavata Interval Zone (Coniacian), and Diacarinella asymetrica Total Zone (Santonian).
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Iranian Journal of Earth Sciences
,
Issue2,Year,
Winter
2017
In this research, the microbiostratigraphy and depositional environmental implications related to the Surgah Formation at the northern flank of the Kuh-e Sepid anticline in the Lorestan Basin are discussed. A study of small planktonic foraminifera from the 101-m-thick S More
In this research, the microbiostratigraphy and depositional environmental implications related to the Surgah Formation at the northern flank of the Kuh-e Sepid anticline in the Lorestan Basin are discussed. A study of small planktonic foraminifera from the 101-m-thick Surgah Formation led to the identification of three Turonian–Santonian biozones: (1) Helvetoglobotruncana helvitica, (2) Marginotruncana sigali, and (3) Dicarinella concavata. The age of the Surgah Formation in the study area is determined as Turonian–Santonian. The Surgah Formation overlies the Sarvak Formation and underlies the Ilam Formation in the studied stratigraphic section. Based on an analysis of pelagic foraminiferal assemblages and microfacies features, seven different microfacies have been recognized. These can be grouped into three depositional environments: the inner, middle, and outer ramps.
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The Taleh-Zang Formation is a predominantly carbonate lithostratigraphic unit that crops out in Lorestan sedimentary basin, southwestern Iran . Lorestan sedimentary basin, formed as a foreland basin in Central Zagros, is characterized by a relatively continuous Cretaceo More
The Taleh-Zang Formation is a predominantly carbonate lithostratigraphic unit that crops out in Lorestan sedimentary basin, southwestern Iran . Lorestan sedimentary basin, formed as a foreland basin in Central Zagros, is characterized by a relatively continuous Cretaceous to Miocene time. In this paper, the microbiostratigraphy of the Taleh- Zang Formation in seven measured stratigraphic sections (Taleh- Zang type section, Kialou, Veisian, Chenar, Ghalebi, Darabi and Chahr Zebr) are is discussed. In all sections, the lower and upper boundaries of the Taleh- Zang Formation with Amiran and Kashkan Formations are conformable. Microbiostratigraphic data mainly based on foraminifera indicate the Middle Paleocene to Late Paleocene for the Taleh- Zang Formation for Veisian and the Early to Late Paleocene at Ghalebi, Darabi and Chenar, the Middle Paleocene for For Chahr Z¹ebr, the Late Paleocene to the Middle Eocence at the type section and the Late Paleocene to Early Eocene at the Kialou section.
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