Qom Formation

Open Access Article

1 - Microfacies, sedimentary environment and sequence stratigraphy of the Qom Formation in East Siyah Kuh surface section (South of Garmsar)
Mahmoud Jalali Mahmoud Jalali محمد حسين آدابي

This paper represents the sequence stratigraphic analysis of the Oligo-Miocene shallow water carbonate succession of the Qom Formation, east of Kuh Siah outcrop (South of Garmmsar). The study is based on the lithosratigraphy, biostratigraphic framework (in the contex More

This paper represents the sequence stratigraphic analysis of the Oligo-Miocene shallow water carbonate succession of the Qom Formation, east of Kuh Siah outcrop (South of Garmmsar). The study is based on the lithosratigraphy, biostratigraphic framework (in the context of European standard biozonation), microfacies, paleoenvironmental interpretation and sequence srtatgraphic concepts. In this section, only f to c1 members of the Qom Formation can be differentiated. The biostrtigraphic results revealed that the benthic foraminiferal composition of the studied section has close affinities with coeval assemblages in Western Tethys and the Middle East. The larger foraminifera associations in the Qom Formation mark the SBZ 23 to 25 zones, referring to a time span from the late Chattian to Burdigalian. Based on the micropaleontological studies, the age of late Chattian (SBZ 23) is ascribed to c1 member which previously considered as Aquitanian, in East of Siah Kuh surface section. Sedimentary environment of the Qom Formation is related to a carbonate ramp platform. Based on sedimentary texture and percentage of skeletal and non skeletal allochems, 1 lithofacies and 13 microfacies from inner to outer ramp were determined. The sequence stratigraphic studies led to the determination of four 3rd order sequences. The first sequence with the Chattian age includes c1 and c2 members. The second sequence with the Aquitanian age includes c3, c4 and d members. The e and f members belong to third and fourth sequences with the age of Burdigalian. Manuscript profile

Open Access Article

2 - Microfacies, Sedimentary Environment and Sequence Stratigraphy of the Qom Formation, Deh Namak, Northwest of Garmsar
Jahanbakhsh Daneshian Asadi Mehmandosti yousef ramezani

Deh Namak section is exposed along the most northern point of the Qom Formation, where the Central Iran zone and Alborz zone come together. The study of microfacies, sedimentary environments and sequence stratigraphic features of the Qom Formation in this area can h More

Deh Namak section is exposed along the most northern point of the Qom Formation, where the Central Iran zone and Alborz zone come together. The study of microfacies, sedimentary environments and sequence stratigraphic features of the Qom Formation in this area can help to understand the situation of the Qom sedimentary basin in the northern part, bordering the Alborz zone. 166 samples of the Qom Formation in Deh Namak section in the northwest of Garmsar are investigated. Microfacies analysis of these sedimentary rocks indicates that according to sedimentary environment they consist of nine microfacies belonging to four facies belts including tidal flat, agoon, shoal/reef sediments and slope of platform. Due to the absence of the gravitational and turbidity sediments and abundance of reef/shoal sediments, a rimmed carbonate shelf depositional environment is suggested in which more sediments were precipitated in shallow water. In this model, deep facies of the basin did not spread and the deepest facies belong to the slope. Also, sequence stratigraphic studies show that the Deh Namak section is composed of four sedimentary sequences of third- order, two types II and one type I sequence boundaries were recognized in this formation. Manuscript profile

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3 - Biostratigraphy and paleoecology of the e Member of the Qom Formation based on Ostracoda at Cheshmeh Boroun section, West of Qom
Daneshian مسعود گودرزی

The aim of this study is determining systematics and identification of ostracods genera and species of the e Member of the Qom Formation at the studied section (Cheshmeh Boroun) for biostratigraphy and age determination, and palaeoecological investigations considering t More

The aim of this study is determining systematics and identification of ostracods genera and species of the e Member of the Qom Formation at the studied section (Cheshmeh Boroun) for biostratigraphy and age determination, and palaeoecological investigations considering the abundance and diversity changes of ostracods based on the collected data. The abundance and diversity of the ostracods taxa such as Paracypris، Aurila ،Ruggieria ،Loxochoncha ، Krithe، Xestoleberis, Cytherella mostly suggest a marine environment with normal salinity and warm climate from ecological point of view. However, the increase and decrease of these taxa in the studied section indicate the diversity and abundance changes is related to environmental changes. In fact, this shows the instability of the environmental conditions which seems to be affected by the changes of food and oxygen values, and water turbulence. Based on ostracods assemblages, an Early Miocene age ( Aquitanian- Burdigalian) is exclusively suggested for the e Member of the Qom Formation at Cheshmeh Boroun stratigraphic section. Manuscript profile

Open Access Article

4 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan

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

5 - 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

Open Access Article

6 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan

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

7 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan
Mahsa Noori

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

8 - Study of original carbonate mineralogy of the Qom Formation using petrography and geochemical evidence in celestite ore section, Madabad, south of Zanjan

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

9 - 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

10 - Geochemical analysis &petrophysical studies: An approach to clay minerals investigation of E member of Qom Formation, Sarajeh gas field
عباس دهکار سهیلا اصلانی

Geochemical and petrophysical studies on E member of Sarajeh Gas field shows presence of different type of clay minerals. Petrography studies along with XRD , SEM and EDX analysis on the present samples, indicate presence of Illite, Chlorite and expandable clay mine More

Geochemical and petrophysical studies on E member of Sarajeh Gas field shows presence of different type of clay minerals. Petrography studies along with XRD , SEM and EDX analysis on the present samples, indicate presence of Illite, Chlorite and expandable clay minerals. Expandable clays comprise, smectite and mixed layer or interstratified Illite/Smectite (I/S) minerals. Petrophsical studies show Th/K on NGS log in Sarajeh, well 12, composed mainly, Illite, chlorite with minor amount of interstratified Illite/Smectite (I/S). Geochemical studies confirm validity of petrophysical results. The presence of different clay minerals of Qom formation in E member, Sarajeh Gas field, may have significant impact on petrophysical properties of reservoir, and hence affect reservoir productivity as well as cause problem during drilling operations. Manuscript profile

Open Access Article

11 - Reconstruction of sedimentary environment, and depositional sequences based on Microfacies of the Qom Formation in the Kahak area (Southwest of Qom city)
Mahdiyeh Mahyad Hosyen Vaziri moghadam

In this study, sedimentary environment and depositional sequences were reconstructed based on distribution of microfacies in the sequence belong to the Qom Formation in the Kahak area. The formation was formed alternation of shale and limestone. The boundary between the More

In this study, sedimentary environment and depositional sequences were reconstructed based on distribution of microfacies in the sequence belong to the Qom Formation in the Kahak area. The formation was formed alternation of shale and limestone. The boundary between the Qom Formation and the volcanic rocks is unconformable. In addition, the Upper Red Formation in the Kahak area unconformably overlies the Qom Formation. In the study area, 6 microfacies, and 1 terrigenous facies (shale) for the Qom Formation were identified by study of these rock samples. The Qom Formation was deposited in an open-shelf carbonate platform in the study area. This platform can be divided into two environments that the environments consist of the inner shelf (restricted lagoon and semi-restricted lagoon) and middle shelf. Finally, two third-order sequences were identified based on distribution of microfacies in the Kahak area. Manuscript profile

Open Access Article

12 - Foramniferal morphogroups of the Qom Formation in E Sirjan and SW Kashan: implication for paleoenvironmental and paleoecological interpretations
Ebrahim Mohammadi

The Qom Formation is the main reservoir and source rock of hydrocarbons in central Iran. Foraminifera are now central to our ability to date, correlate and analyse the sedimentary basins that are currently key to the economic wellbeing of the world. Morphogroup analysis More

The Qom Formation is the main reservoir and source rock of hydrocarbons in central Iran. Foraminifera are now central to our ability to date, correlate and analyse the sedimentary basins that are currently key to the economic wellbeing of the world. Morphogroup analysis, due to independence of species level taxonomy, as wel as permit to comparison of assemblages of differing ages, is a useful tool for ecological and palaeoecological interpretation. It is independent of species level taxonomy and is thus relatively elementary to translate from one worker to another. Foramniferal study of the Qom Formation in the Bujan (eastern Sirjan; with Rupelin-Chattian in age and 156 m thickness) and Varkan (southwestern Kashan; with Rupelin in age and 190 m thickness) sections resulted in identification of seven morphogroups. The morphogroups were distinguished according to test/shell morphology and architecture (general shape, mode of coiling, and arrangement and number of chambers), inferred life habitat either living on the surface of the sediments or within the sediments (epifaunal and infaunal), and feeding strategy (suspension-feeder, herbivore, etc.). Generaly, epifaunal morphogroups were dominated in both study sections. The morphogroup analyses showed variations in the percentage of the dominant morphotypes, suggesting fluctuations in the paleoecological conditions. In the Bujan section, the Rupelin deposits are dominated by calcareous porcelaneous morphogroups; while the Chattian deposits are dominated by hyaline morphogroups, which indicates the lower and upper parts were deposited in inner ramp (lagoonal environments) and middle ramps, respectively. This significant change through time reffers to gradual increasing of the basin depth, decreasing the light intensity, reducing the salinity and decreacing the nutrient level. De dominance of the hyaline morphogroups throughout of the Varkan section is indicative of the deposition in middle ramp environments with normal salinity under meso-photic to oligo-photic conditions. Manuscript profile

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13 - Qom Formation, Microfacies, Depositional sequence, Maragh area.
Amrolah Safari Hossein Ghanbarloo Ebrahim Mohammadi

The Qom Formation is located at the Maragh area (20 kilometers southwest of Kashan). The formation with 216 m thickness contains shale and limestones. Volcanic rocks unconformably are covered by the Qom Formation. The upper boundary of the Qom Formation with the Upper R More

The Qom Formation is located at the Maragh area (20 kilometers southwest of Kashan). The formation with 216 m thickness contains shale and limestones. Volcanic rocks unconformably are covered by the Qom Formation. The upper boundary of the Qom Formation with the Upper Red Formation is also unconformable. Nine microfacies and terrigenous facies were identified based on the main components and sedimentological features. These microfacies and terrigenous facies were deposited on an open-shelf carbonate platform. Three environments were recognized in this carbonate platform. These environments include the inner shelf (restricted and semi-restricted lagoon), middle shelf, and outer shelf. In addition, three third-order and one incomplete depositional sequences were identified based on the vertical distribution of microfacies. Manuscript profile

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14 - Geology, mineralization and genesis of the Madabad celestite deposit, south Zanjan
مهسا نوری Hossein Kouhestani قاسم نباتیان میرعلی اصغر مختاری افشین زهدی

Rock units in the Madabad celestite deposit are composed of medium to thick-bedded and massive limestone interlayered with marly limestone and marl units of the Qom Formation (lower Miocene). Mineralization occurs as lens-shaped orebody, hosted by limestone units of mem More

Rock units in the Madabad celestite deposit are composed of medium to thick-bedded and massive limestone interlayered with marly limestone and marl units of the Qom Formation (lower Miocene). Mineralization occurs as lens-shaped orebody, hosted by limestone units of member of the Qom Formation usually crosscutting bedding of the host rocks. Three stages of mineralization occurred in the Madabad deposit. The first stage is characterized by calcite formation during syn-depositional to syn-diagenesis processes. The second stage is related to hydrothermal processes that are distinguished by formation of fine-grained and sugary crystals of massive stage-1 celestite, vein-veinlets of coarse-grained stage-2 celestite along with minor strontianite and barite, coarse-grained euhedral crystals of stage-3 celestite with vug infilling texture, and finally late-stage quartz and calcite vein-veinlets. Stage three includes supergene processes. Hydrothermal alteration includes dolomitization, calcitization and silicification. Celestite along with minor strontianite and barite are ore minerals, and calcite, dolomite, quartz and iron oxides-hydroxides are gangue minerals at Madabad. The ore minerals show vein-veinlets, vug infilling, brecciated and cataclastic textures. Microthermometric measurements of two-phase liquid-rich fluid inclusions hosted in celestite II indicate that salinities values range from 6 to 18 wt.% NaCl equiv. (avg. 10.6 wt.% NaCl equiv.). These inclusions have homogenization temperatures range from 248 to 365 °C, with an average of 278 °C. These data indicate a minimum trapping depth of 510 m for the Madabad deposit. Sr was originated from evaporate units within the marly parts of the Qom Formation and volcanic units of the Karaj Formation. Characteristics of the Madabad deposit are similar to epigenetic replacement celestite deposits. Manuscript profile

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15 - Microfacies and Sequence stratigraphy of the the Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan
Amir Pedramara Mehdi Yazdi Zahra Maleki Ali Bahrami

In this research, the deposits of the Oligocene-Miocene Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan were studied. According to the field observations and thin section analysis in Carbonate part of the mentioned sect More

In this research, the deposits of the Oligocene-Miocene Qom Formation in Kuh-e Charkheh (Natanz), Western Zefreh and Varton sections, northeastern Isfahan were studied. According to the field observations and thin section analysis in Carbonate part of the mentioned sections, 8 microfacies were identified, which were deposited from shallow part of lagoon to open marine and the sedimentary environment of 3 sections due to absence of reef and presence of bioclastic barrier and absence of spillage, the homoclinal carbonate ramp was detected. According to the sequence stratigraphic studies, each of the studied sections has two 3rd sequences. In Kuh-e Charkheh section, both sequences include of TST and HST, which are separated by sequence boundary SB2. In the western Zefreh section, the first sequence includes of TST and HST that is separated from the second sequence (include of LST, TST and HST) with sequence boundary SB1. In the Varton section, the first sequence is aggredation type and separated from the second sequence, which include TST and HST by a sequence boundary SB2. Manuscript profile

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16 - Biostratigraphy and palaeoecology of Qom formation in the Ghamsr section (SW of the Kashan)
tayyeb binazadeh Amrollah Safari Hosyen Vaziri moghadam

In order to study the biostratigraphy and palaeoecology, the Qom Formation has been studied in the Ghamsar section of Kashan. The studied section, with a thickness of 314 m, consists of medium to thick-bedded to massive limestones and shale. The Qom Formation overlies t More

In order to study the biostratigraphy and palaeoecology, the Qom Formation has been studied in the Ghamsar section of Kashan. The studied section, with a thickness of 314 m, consists of medium to thick-bedded to massive limestones and shale. The Qom Formation overlies the Eocene volcanic rocks in the Ghamsar section and is covered by the Recent alluvial sediments. A total of 21 genera and 9 species of benthic foraminifera were identified in this section and the results indicated the age of Rupelian-Chattian. According to the above palaeoecological conditions, in the lower parts of this section (Rupelian), light conditions are euphotic and nutrient conditions are first eutrophic and then Meso-oligotrophic with mainly normal sea salinity. During Chattian, the trophic state was mainly meso-oligotrophic with normal salinity, and salinity varied between 40 and 50 PSU. Light conditions also were between aphotic and mainly meso-oligophotic. Large benthic foraminifera with hyaline walls, such as Amphistegina, Lepidocyclinide and Nummulitide, in shallow environments with high energy, have thicker shells and smaller shell size, and in deep environments, due to reduced light intensity and low water circulation, they have thinner and more elongated shells. The results of the morphometry of 186 samples of Amphistegina show that the seawater depth in Ghamsar section (Rupelian-Chattian) fluctuated from less than 11 meters to less than 44 meters. Manuscript profile

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