Sedimentology
Afshin Karimkhani-Bahador; Sadat Feiznia; Mohsen Aleali; Mehran Arian
Abstract
To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy ...
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To prepare sedimentological data, 98 surface sampling stations have been designed from the seabed in the continental shelf in the southern part of the Caspian Sea and along the coast of Iran. Indicators such as the type and amount of sediment load transported to the sedimentation environment, the energy of waves and sea currents, as well as how the slope of the seabed changes, play a role in the production and diversity of the sedimentary facies. 9 sedimentary facies are the most abundant in the surface deposits of this area and on average, in the sediments of the continental shelf, there are 1% by weight of coarse-grained particles, 25% by weight of medium-grained particles and 74% by weight of fine-grained particles. The composition of sedimentary facies in this area is controlled by indicators such as the size of sedimentary particles, the amount of sedimentary load carried to the environment, the energy of waves and sea currents, and how the slope of the seabed changes. In the marine environment of the study area, sub-sedimentary environments, Backshore, Foreshore, Shoreface, Offshore transition zone and offshore can be identified. The two facies of slightly gravelly Mud and Mud are more abundant than other facies.
Stratigraphy and Palaeontology
Ali Jalali; Hamed Yarahmadzahi; Mehran Arian; Abdollah Saidi; Seyed Mohsen Aleali
Abstract
The Shishtou section is located in the north of Tabas Ghezelin and Asselian sequences of Zaladou formation with 60 m thickness are divided into five units, includes sandstone, limestone, shale, sandy limestone and limestone. The lower boundary of the Gzhelian deposits with disconformity on top of the ...
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The Shishtou section is located in the north of Tabas Ghezelin and Asselian sequences of Zaladou formation with 60 m thickness are divided into five units, includes sandstone, limestone, shale, sandy limestone and limestone. The lower boundary of the Gzhelian deposits with disconformity on top of the Moscovian deposits of the Abshani formation. The upper boundary of these deposits with the Tighe-Madanou formation is continuous. The assemblages of fusulinids in the Shishtou section such as Ruzhenzevites-Rauserites-Triticites are identified in the upper part of Gzhalian previously reported from equal deposits in Darvaz, Fergana, Southern Urals, Donetsk and Carnic of Alps, as well as, Central Iran, Central Alborz and Sanandaj-Sirjan zones. Also, different species of Sphaeroschwagerina, Pseudoschwagerina and Likharevites, which illustrate the Asselian age, represent the Carboniferous-Permian boundary in the studied section and allow for comparability with other structural-sedimentary zones of Iran, including Central Iran , Central Alborz (Doroud Group) and Sanandaj-Sirjan zone. This equivalence expresses the transgressive of sea level in different parts of Iran in the late Carboniferous and early Permian periods. In Shishto section 15 genera ,35 species and 2 subspecies of Fusulins have been identified, some of which are reported for the first time from Iran.
Sedimentology
Zeinab Sheikholeslami; , Mahmoudreza Majidifard; Seyed Mohsen Aleali; Mohammad Javanbakht; Morteza Taherpour Khalilabad
Abstract
A unique basement of Kopeh Dagh sedimentary basin is located and investigated in Agh-darband area, northeastern Iran. The second formation of the Agh- darband group, the Nazarkardeh Formation is cropped out in the area by carbonate and volcanogenic successions. This Formation with Anisian age is ...
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A unique basement of Kopeh Dagh sedimentary basin is located and investigated in Agh-darband area, northeastern Iran. The second formation of the Agh- darband group, the Nazarkardeh Formation is cropped out in the area by carbonate and volcanogenic successions. This Formation with Anisian age is overlaid by the Sina Formation, Ladinian age with a sharp boundary and is underlaid by the Sefidkuh Formation with late Scythian in age by a gradual boundary. During this research, four stratigraphic sections are measured from petrology, sequence stratigraphy, microfacies and sedimentary basin points of view. Next this measurement, 300 samples are token and 100 thin sections are made. 11 microfacies with 1 hybrid facies and 3 terrestrial facies are determined. By high resolution studies on these data, this Formation is deposited in lagoon, shoal and open marine which is deposited between the Sefidkuh Formation (carbonate ramp) and the Sina Formation (marginal shelf), so that the depositional environment of the Nazarkardeh Formation is determined as a transitional environment from carbonate ramp to marginal shelf. The existence of hybrid facies show the volcanic activities during deposition of this Formation. the existence of intraformation and monomictic conglomerate in the last depositinal stages of this formation, shows the falling and collapse facies next to the deep floor changes of the sedimentary basin. The sea level change graphs in A, B, C and D stratigraphic sections in contrast with sea level change graphs of Anisian (middle Triassic) shows a third level sequence stratigraphy and is markable by a non-erosional boundary (SB2) on the basis on top of the A, B, C and D stratigraphic sections.
Sedimentology
keyvan ahzan; Nader Kohansal Ghadimvand; Seyed Mohsen Aleali; Davood Jahani
Abstract
The Jahrum Formation (Paleocene-Mid Eocene) is one of the most important reservoir units in the Zagros basin and the Persian Gulf. The thickness of this formation in Binaloud oil field in Persian Gulf, which mainly consists of limestones and Dolomites, is about 660 meters. In this research, depositional ...
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The Jahrum Formation (Paleocene-Mid Eocene) is one of the most important reservoir units in the Zagros basin and the Persian Gulf. The thickness of this formation in Binaloud oil field in Persian Gulf, which mainly consists of limestones and Dolomites, is about 660 meters. In this research, depositional environment, sequence stratigraphy and effective diagenesis processes on Reservoir quality of the Jahrum Formation were investigated in Binaloud oil field. The Jahrum succession, which consists of crystalline limestones and dolomites, is overlain by the Asmari Formation and is underlian by the Tarbur Formation unconformably. According to study of cutting samples, eleven microfacies that were deposited in four facies belts, have determined . The most important diagenetic process that was observed in this formation as follows: bioturbation, cementation, dolomitization, dissolution, porosity generation and fracture systems wich is worthy to mation bioturbation and anhydrite cement causes the reduce of reservoir quality and dolomitization , dissolution and secondary porosity causes the reservoir quality. improvement most of facies jahrum formation are mud supported and have very low primary porosity. According to sequence stratigraphy studies, a third order sedimentary sequence with type SB1 boundary was identified in Jahrum subsurface succession.
Sedimentology
B. Mirzapour; R. Lak; M. Aleali; M. Djamali; R. Shahbazi
Abstract
Lake Urmia is one of the largest salt supersaturated lakes in the world that is located in northwestern Iran. Many wetlands are located around of Lake Urmia, especially in the southern part of the lake. Wetlands are important as a platform for recording environmental and climatic events. The ...
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Lake Urmia is one of the largest salt supersaturated lakes in the world that is located in northwestern Iran. Many wetlands are located around of Lake Urmia, especially in the southern part of the lake. Wetlands are important as a platform for recording environmental and climatic events. The subject of this research is studying sedimentology and statistical parameters of sedimentology in the analysis of different sedimentary environments in the sediments of southern wetlands around Lake Urmia, including Kani Barazan and Solduz wetlands. The purpose of this study is reconstructing the fluctuations of the water table of Lake Urmia and its effect on wetland areas in the Holocene period. For this purpose, sedimentary cores with maximum depth of 12 meters and total depth of about 200 meters using a handi auger and 8 hole cores by a vibra corer were collected and examined. Sedimentary facies were identified and separated based on texture and sediment structure, composition of destructive sediments and organic matter, color, presence of plant remnant and shell residues and other macroscopic components. Sampling was performed based on changes in the type of sediments and sedimentary facies. 150 sediment samples were separated for grain size analysis. The samples were analyzed using two methods, wet sieving and particles smaller than sand (silt and clay) by laser device (Laser particle Sizer Analysette). Statistical parameters of sedimentology were calculated using Sedilizer software and were analyzed by SPSS software. Two samples of plant remnant were dated by C14-AMS isotope method. The results indicate that there are 8 facies, belonging to 3 sedimentary environments of lake, wetland and alluvial. The dating results show the average sedimentation rate in the southern part of Lake Urmia is about 0.5 mm per year. However, sedimentation rates vary in different sediment depths. According to the analysis of different cores, the reconstruction of the paleogeography of the south of Lake Urmia and it`s extention had been done in the last 20,000 years. This study shows that in the late quaternary Lake Urmia has expanded to the beginning of the current Siminehrud. At the late Pleistocene and the early Holocene, the coastline regression in the southern part and the alluvial sediments of the Zarrinehrood and Siminehrood rivers occurred in the south of the region. The late Holocene was associated with decreasing water table, slightly dry conditions (around 4000 years ago) and the expansion of marginal playa. The situation in the region has been permanent for about 2000 years.
Sedimentology
Sh. Erfan; K. Rezaei; R. Lak; S. M. Ale Ali
Abstract
Lake Urmia is the greatest hayper salin Lake in the world. This Lake, located in Azerbaijan area, Northwest of Iran is an intra-continental sedimentary basin. Its area is about 6000 km2 with an average water depth of 6 meter. Evaluation of past climate change in Lake Urmia, according to Clay Minerals, ...
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Lake Urmia is the greatest hayper salin Lake in the world. This Lake, located in Azerbaijan area, Northwest of Iran is an intra-continental sedimentary basin. Its area is about 6000 km2 with an average water depth of 6 meter. Evaluation of past climate change in Lake Urmia, according to Clay Minerals, is the main subject for current study. For mineralogical and sedimentological investigations 18 sediment cores were collected from the east and west of Urmia lake. 96 samples from 18 sediment cores in transect to the center of lake were collected and studied by X-ray diffraction (XRD) technique. The clay minerals include Kaolinite, Illite and Montmorillonite. Kaolinite and Illite are the most important clay minerals in the Coastal plain of urmia lake. Origins of clay minerals in the Coastal plain of urmia lake are generally detrital, occurred by physical weathering and indicate composition of bed rock. The study of surface sediments indicates that amount of clay minerals from margin to center of the lake such as another detrital mineral (Quartz) is decreased. In addition, amount of them towards depth is increased. Therefore, it shows the presence of a high water level and cold - humid climate in the past (late Pleistocene).
Stratigraphy and Palaeontology
kiana kiarostami; Darioush Baghbani; Seyed Mohsen Aleali; Seyed Ali Aghanabati; Mohammad Parandavar
Abstract
Lithostratigraphy and biostratigraphy studies on the Sarvak Formation in type section (Tang- e Sarvak, Northwest of Behbahan) show that this Formation has 710 meter thicknesses that divided in to four lithostratigraphic units. The Sarvak Formation in type section rests on the Kazhdumi Formation conformably ...
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Lithostratigraphy and biostratigraphy studies on the Sarvak Formation in type section (Tang- e Sarvak, Northwest of Behbahan) show that this Formation has 710 meter thicknesses that divided in to four lithostratigraphic units. The Sarvak Formation in type section rests on the Kazhdumi Formation conformably with gradational contact (black shales and black argillaceous limestone) and under the Gurpi Formation with disconformity boundary. In this study 8 genus and 9 species of planktonic foraminifera and 34 genera and 33 species of benthic foraminifera have been reported. Four biozones based on (wynd, 1965) and two biozone based on) Premoli Silva and Verga 2004) have been reported as follow; Four biozones based on Wynd 1965: 1- Favusella washitensis range Zone # 23,2- '' Oligostegina'' facies # 26,3- Rudist debris # 24, 4- Nezzazata– Alveolinids Assemblage Zone # 25, Tow biozones based on Premoli Silva and Verga 2004: 1-Muricohedbergella planispira Zone, 2-Ticinella primula Zone. It can propose an Albian- Cenomanian age for Sarvak Formation based on these biozones and also it can recognize Albian-Cenomanian boundary on occurrence of Muricohedbergella planispira and Whiteinella sp. in lower part of this Formation.
Petroleum geology
ayeshah salmani; Hossain Rahimpour-Bonab; Mohsen Ranjbaran; Seyed Mohsen Aleali
Abstract
Asmari Formation (Oligocene - Miocene) is the first fractured proliferous carbonate reservoir that ever known in the world and is the most important hydrocarbon reservoir in Iran. The large quantity of the produced oil in Dezful Embayment is from this formation. Thin section studies in this formation ...
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Asmari Formation (Oligocene - Miocene) is the first fractured proliferous carbonate reservoir that ever known in the world and is the most important hydrocarbon reservoir in Iran. The large quantity of the produced oil in Dezful Embayment is from this formation. Thin section studies in this formation lead to identification of eight microfacies related to the homoclinal ramp with three subdivisions (inner ramp, middle ramp and outer ramp). Many diagenetic processes such as; micritization, neomorphism, bioturbation, dolomitization, dissolution, cementation, mechanical and chemical compaction, fracturing have affected the Asmari carbonates in studied oil field during eogenesis, mesogenesis and telogenesis processes. Three sequences (third order) have been identified based on sequence stratigraphy studies. Based on all results from this study it could be pointed out that; dolomitization, dissolution and cementation are the most important factors that controlled the reservoir quality in this field. Cementation (calcite and anhydrite cements with different fabrics) reduced reservoir quality in different facies. Seemingly, fabric destructive dolomitization increased reservoir quality with creating intercrystaline porosity in mudstone facies and connecting isolated pores (via dissolution) in most of facies. Dissulotion has prime importance where occurred and increased reservoir quality. Contrasting to the other Asmari hydrocarbon fields in Zagros which fracturing is the most important factor in increasing reservoir quality, in Naft-Safid oil field, most of fractures have been filled by calcite cement. Thus, diagenetic imprints (such as dissolution and dolomitization) have more effects on increasing reservoir quality than fracturing.