Afshin Zohdi Articles List

List of Articles Afshin Zohdi

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1 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan
Afshin Zohdi Hossein Kouhestani

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper More

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper Red Formation. In the Madabad celestite deposit (south of Zanjan), the Qom Formation is composed of 190 m of medium to thick-bedded and massive limestone, marly limestone and marl. Five main microfacies are identified in the limestone units of the Qom Formation in the Madabad area. These microfacies probably were deposited on a shelf carbonate platform. Petrographic studies suggest original calcite mineralogy for limestone units of the Qom Formation in the Madabad area. Geochemical studies (Ca, Mg, Na, Sr, Mn and Fe) also represent the original calcite mineralogy in a closed diagenetic system with low dissolution rates. These evidence show significant role of fractures rather than diagenetic processes such as dissolution for increasing the reservoir quality of the Qom Formation for the oil and gas fields (such as Serajeh and Alborz) of central Iran. Manuscript profile
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2 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan
Afshin Zohdi Hossin Kohestani Ghsem Nabatian Mir Ali Asghar Mokhtari

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper More

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper Red Formation. In the Madabad celestite deposit (south of Zanjan), the Qom Formation is composed of 190 m of medium to thick-bedded and massive limestone, marly limestone and marl. Five main microfacies are identified in the limestone units of the Qom Formation in the Madabad area. These microfacies probably were deposited on a shelf carbonate platform. Petrographic studies suggest original calcite mineralogy for limestone units of the Qom Formation in the Madabad area. Geochemical studies (Ca, Mg, Na, Sr, Mn and Fe) also represent the original calcite mineralogy in a closed diagenetic system with low dissolution rates. These evidence show significant role of fractures rather than diagenetic processes such as dissolution for increasing the reservoir quality of the Qom Formation for the oil and gas fields (such as Serajeh and Alborz) of central Iran. Manuscript profile
Open Access Article
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3 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan
Afshin Zohdi Hossein Kohestani Ghasem Nabatian Mirali Mokhtari

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper More

The Qom Formation is the only hydrocarbon reservoir in the central Iran sedimentary basin. In most parts of the central Iran, the Qom Formation conformably overlies the Lower Red Formation with an erosional discontinuity and is in turn conformably overlain by the Upper Red Formation. In the Madabad celestite deposit (south of Zanjan), the Qom Formation is composed of 190 m of medium to thick-bedded and massive limestone, marly limestone and marl. Five main microfacies are identified in the limestone units of the Qom Formation in the Madabad area. These microfacies probably were deposited on a shelf carbonate platform. Petrographic studies suggest original calcite mineralogy for limestone units of the Qom Formation in the Madabad area. Geochemical studies (Ca, Mg, Na, Sr, Mn and Fe) also represent the original calcite mineralogy in a closed diagenetic system with low dissolution rates. These evidence show significant role of fractures rather than diagenetic processes such as dissolution for increasing the reservoir quality of the Qom Formation for the oil and gas fields (such as Serajeh and Alborz) of central Iran. Manuscript profile
Open Access Article
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4 - Facies analysis and sedimentary environment of the Jeirud Formation in Garmabdar section, central Alborz: with emphasis on paleoredox conditions during deposition of black shales
Nahid Karimi Najmeh Etemad-Saeed Aram Bayet-Goll Afshin Zohdi Tomas Kumpan
20.1001.1.17357128.1401.16.63.4.5

The late Devonian has been associated with major global climate changes, widespread anoxia events, and the Hangenberg Crisis. The main aim of this study is to explore the relationship between paleoenvironment and paleoredox condition during deposition of the lower Devon More

The late Devonian has been associated with major global climate changes, widespread anoxia events, and the Hangenberg Crisis. The main aim of this study is to explore the relationship between paleoenvironment and paleoredox condition during deposition of the lower Devonian Jeirud Formation in the Garmabdar section, northeast of Tehran. The Jeirud Formation in the Garmabdar section, with a thickness of about 280 m, is composed of siliciclastics, carbonates, carbonate-siliciclastic hybrids and phosphorite deposits. Sedimentary facies analysis led to recognition of three siliciclastic facies associations related to estuarine environments under the influence of waves, shoreface and offshore and two carbonate facies associations related to intertidal and subtidal environments. Moreover, the geochemical paleoredox proxies (such as U/Th and V/Cr) also suggest prevailing anoxic conditions during deposition of black shales and phosphorites in the studied section. In overall, these results suggest that there is a good agreement between the depth of the depositional environment and anoxic conditions during deposition of black shales of the Jeirud Formation. Manuscript profile
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5 - Geology, mineralization, mineralogy, structure and texture in the Ghezeljeh Cu, Pb-Zn deposit, NW Zanjan
Seyedeh Aliyeh Seyedeh Aliyeh Ghasem Nabatian Afshin Zohdi Armin Salsani
20.1001.1.17357128.1402.17.65.4.6

Ghezeljeh deposit is located in the Central Iranian zone, in the Zanjan province and northeast of the Mahneshan city. The rock units in this area belongs to the Oligo-Miocene, which contain Lower Red, Qom and Upper Red formations. The Upper Red Formation in Ghezeljeh re More

Ghezeljeh deposit is located in the Central Iranian zone, in the Zanjan province and northeast of the Mahneshan city. The rock units in this area belongs to the Oligo-Miocene, which contain Lower Red, Qom and Upper Red formations. The Upper Red Formation in Ghezeljeh region has about 750 m thickness and mainly consists of brown to green marl intercalations with sandstones. In this area, the alternation of marl and sandstone sequences contain sandstone layers with thickness about 2 to 8 meters, which in two horizons, the copper-lead and zinc mineralization has occurred. Copper mineralization, in addition to being observed inside the sandstone unit. In the Ghezeljeh deposit, the host rocks of the copper ores, are gray sandstones and conglomerates which are intercalated with red and gray marl units. According to field and microscopic studies, the main ore mineral consist of pyrite, chalcocite, chalcopyrite, bornite, galena and sphalerite which associated with the secondary minerals such as serosite, malachite, azurite, covellite, smithzonite and goethite. The ore mineral textures consist of disseminate, framboidal pyrite, solution seams, interparticle cement, replacement and relict. Preliminary fieldwork studies in the Ghezeljeh region also show that organic matter including plant remains and diagenetic pyrite are the effective factors to concentrate and mineralization. It is considerable that the grade of lead, zinc and copper, in Ghezeljeh deposit are 6%, 3% and 1%, respectively. Generally, host rock, tectonic setting, sedimentary environment, mineralogy, texture, mineralization control factors all confirm that the studied mineralization has more similarities with Redbed type copper deposits. Manuscript profile

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List of Articles Afshin Zohdi