S. Alipour; Kh. Mosavi-ovenlegi; E. Hosseini; Sh. Aslanpour; Z. Haseli
Abstract
The Urmia Salt Lake as the largest hyper saline lake of the world is located between west and east Azerbaijan provinces, NW Iran. Geochemistry of trace and rare earth elements of bed sediments taken from 25 Cm of the lower most of 1.5 meters depth of drilled holes in 130 samples between 2014-2015 ...
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The Urmia Salt Lake as the largest hyper saline lake of the world is located between west and east Azerbaijan provinces, NW Iran. Geochemistry of trace and rare earth elements of bed sediments taken from 25 Cm of the lower most of 1.5 meters depth of drilled holes in 130 samples between 2014-2015 were investigated. General geochemical composition of samples revealed a very heterogeneous variation of major oxides at NW, NE, SW and SE parts of the lake. MgO, CaO and Na2O show a high enrichment compared to UCC, PAA and NASC values. Main minerals of the bed sediments include halite, calcite, ankerite, quartz, orthoclase, augite, hornblende and chlorite. The overall geochemical composition of sediments, resemble ferruginous shale and graywacke sandstone. Weathering in the various parts of the bed sediments is relevant to general climatological characters in the region. Rb and Sr among trace elements show high anomaly in respect to UCC, PAAS and NASC, while Eu indicated high depletion, especially at SW corner of the lake. Geochemical comparisons indicate the major role of different rock units in forming bed sediments rather than sediments carried by entering rivers to the lake.
Stratigraphy and Palaeontology
Mahin mohamadi; R. Shabanian; H. M. Alizadeh
Abstract
This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field ...
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This research has aimed to study the biostrtigraphy and lithostratigraphy of late cretaceous deposits in south of Maracan village , with 320 m thickness.This sequence overlaid the lower cretaceous deposits and have been covered by Quaternary sedimentary and magmatic rocks. Based on field study and lithological diversity 8 lithic zone have been investigated. 102 samples have been picked up systematically from this sequence. This study lead to determining 41 species from 15 genera of planktonic foraminifera.The systematic and classification of fauna are based on The (Postuma 1971) , (Caron1985) , (Loeblich and Tappan 1988) and (Permoli Silva And Verga 2004). .Based on their range chart the bio zonation model for this deposit with 9 Bio Zones as bellow have been suggested and have compared with cretaceous global standard bio zones (Robazynsky and Caron 1985) and (Permoli Silva and Verga, 2004) Dicarinella concavata Interval Zone (Robazynsky and Caron, 1995) Dicarinella asymetrica Total range Zone(Robazynsky and Caron, 1995) Globotruncanita elevata IntervalrangeZone(Robazynsky and Caron, 1995) Globotruncana ventricosa IntervalZone (Robazynsky and Caron, 1995) Rodotruncana calcarata Total range Zone(Robazynsky and Caron, 1995) Globotruncanella havnensis Partial Range Zone (Robaszynski and Caron, 1985) Globotruncana aegyptiaca Interval Zone (Robazynsky and Caron, 1995) Gansserina gansseri Interval Zone (Robazynsky and Caron, 1995) Abathamphalus mayaroensis Total range Zone(Robazynsky and Caron, 1995) The suggested age for th.is sequence based on planktonic foraminifera is upper coniantian to upper Maestrichtian and belong to deep shelf area . Based on the morphology of planktonic foraminifera and their keei we suggest deep sea environment for these deposits.
N. Amel; M. Moayyed; A. Ameri; M. Vosoghi Abedini; M.H. Emami; M. Moazzen
Abstract
The Plio-Quaternary calc-alkaline magmatism in Azerbaijan, northwest Iran, occurs as stratovolcanoes, lava flows and domes consisting of andesitic basalts, andesites, dacites, rhyodacites, and pyroclastic materials. The volcanic rocks unconformably cover the Miocene sedimentary ...
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The Plio-Quaternary calc-alkaline magmatism in Azerbaijan, northwest Iran, occurs as stratovolcanoes, lava flows and domes consisting of andesitic basalts, andesites, dacites, rhyodacites, and pyroclastic materials. The volcanic rocks unconformably cover the Miocene sedimentary formations. The chemistry of the felsic-intermediate volcanic rocks indicates that the parent magmas are medium-K calc-alkaline and metaluminous in nature, and are distinguished by Na2O/K2O> 1. The volcanic rocks are enriched in LILE and LREE, and depleted in Y, Nb, and HREE, and display highly fractionated REE patterns, with no Eu anomaly. They display post-collision and continental margin arcs affinities. The post collision convergence between Arabia and Eurasia continental plates, starting in Miocene, resulted in significant shortening, thickening, and uplift of the crust in northwestern Iran and eastern Turkey, and shaped the present Iran-Turkey Plateau.
The thermal perturbation processes in the underlying asthenospheric mantle led to partial melting at a low degree, producing alkali- basalt magmas, with garnet remaining stable in the source region. The ascent of the basaltic magma and its emplacement in the lower crust resulted in the partial melting of the crustal materials and development of acidic magma. These processes led to the ascent and eruption of the felsic magmas prior to the mafic magmas. Mixing of mantle-derived mafic magmas with felsic magmas of crustal origin, produced hybrid magmas of intermediate composition. The occurrence of inverted volcanic sequences, where olivine-alkaline basalts are underlain by calc-alkaline felsic-intermediate rocks, are typical features of bimodal volcanic activities in the Plio-Quaternary times in Azerbaijan.
There are mineralogical as well as geochemical evidences that AFC-type processes were involved in the evolution of the Plio-Quaternary volcanic rocks in Azerbaijan. A comparison of geological and geochemical characteristics of the Plio-Quaternary volcanic rocks from northwest Iran with those from eastern Turkey indicates that the two areas share similar evolution paths in the petrogenesis of magmatic rocks.
A. Yassaghi; H. Narimani; M. Gh. Hasan goodarzi
Abstract
Structures in fold-thrust belts such as Zagros which are developing mainly along the belt strike often terminate at the transverse structures. The Zagros Mountain Front Fault has cut and displace at different parts by transverse structures. At Dowgonbadan area this fault is intersected by the Kharg-Mish ...
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Structures in fold-thrust belts such as Zagros which are developing mainly along the belt strike often terminate at the transverse structures. The Zagros Mountain Front Fault has cut and displace at different parts by transverse structures. At Dowgonbadan area this fault is intersected by the Kharg-Mish transverse structure. The Mish anticline has transported fault propagation geometry and located on hanging wall of the Mountain front fault. The anticline plunges and rotates when it reaches to the Kharg-Mish transverse fault to the west. In the fault footwall, however, the Dil, Pahn, Sarab and Jafarabad anticlines have rounded geometry and low amplitude show characteristics of the Dezful Embayment zone folds. The Dil and Pahn anticlines with bifurcate geometry and outcrop of Asmari Formation develop parallel to the frontal ramp strike and show footwall anticlines that propagated from the frontal ramp at Dashtak formation as delay structures with respect to the hanging wall structures. The Kharg-Mish fault identify as a lateral ramp on the surface by termination of longitudinal structures and at the depth with thickness and facies changes of the Ilam Formation. The structural characteristics of the Dowghonbadan area in the Zagros Fold-Thrust Belt are analyzed as the interaction of the Mountain Front fault and the Kharg-Mish transverse fault as the frontal and lateral ramps, respectively.
Kh. Khosrotehrani; D. Baghbani; F. Keshani; M. Omrani
Abstract
In order to study Biostratigraphy of Cenomanian – Late Campanian deposits (upper part of Sarvak Fm.,Ilam Fm. and lower part of Gurpi Fm.), kuhe Assaluyeh stratigraphic section selected. Sediments of this interval consist of limestone, argillaceous limestone and marl with thickness of 162 m. In ...
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In order to study Biostratigraphy of Cenomanian – Late Campanian deposits (upper part of Sarvak Fm.,Ilam Fm. and lower part of Gurpi Fm.), kuhe Assaluyeh stratigraphic section selected. Sediments of this interval consist of limestone, argillaceous limestone and marl with thickness of 162 m. In this section Ilam Fm. in age of Santonian overlies Sarvak Fm. disconformably and is underlain by Gurpi Fm. conformably. By micropaleontological study on 55 thin sections, 5 genus and 9 species of planktonic and 16 genus and 13 species of benthic foraminifers were identified. Among distinguished foraminifers, Rotaliidae family forms were studied carefully and revised. It should be mentioned that, 5 genus and 6 species of benthic foraminifers (Rotaliid forms) were recognized in Iran for the first time (in Assaluyeh section) which consist of: Rotorbinella mesogeensis,Rotorbinella campaniola,Iberorotalia reicheli,Calcarinella schaubi, Pararotalia tuberculifera and Pyrenerotalia longifolia. Santonian age was determined for Ilam Fm. by identified foraminifers. In studied section, stratigraphy development of benthic foraminifers was compared by Martinez Biozones Martinez (2007). This biozones were presented on the base of Rotaliid forms for Pyrenees area in Spain. By this comparison, four biostratigraphy zones for upper part of Sarvak and Ilam Fm. are suggested.
Hossein Talebi; Seyed Ahmad Alavi; Shahram Sherkati; Mohammad Reza Ghassemi; Alireza Golalzadeh
Abstract
This paper analyzes in-situ stress field in the Asmari formation with in the complex structures of the Zeloi and Lali oilfields located in the Dezful embayment, SW Iran. The orientation of the maximum horizontal stress, SHmax is determined on the basis of compressive borehole breakouts and drilling-induced ...
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This paper analyzes in-situ stress field in the Asmari formation with in the complex structures of the Zeloi and Lali oilfields located in the Dezful embayment, SW Iran. The orientation of the maximum horizontal stress, SHmax is determined on the basis of compressive borehole breakouts and drilling-induced tensile fractures observed in eight oil wells, in which we focus on well-log based methods and drilling data to estimate stress magnitudes. In situ stress magnitude in studied fields obtained from 1D mechanical earth modeling in key wells. The maximum horizontal stress trend in this area is NE–SW in accordance with the World Stress Map however a stress perturbation has been recognized in some wells of the Lali field which is approximately perpendicular to the expected direction of the maximum horizontal stress. In situ stress magnitudes in the Lali oil wells are consistent with a strike-slip regime, while in the Zeloi oilfield, normal faulting regime is estimated. The observed strike-slip and normal faulting regime in the Lali and Zeloi wells respectively, Supports the idea that the role of overburden stress magnitude is higher than the horizontal stresses. Undoubtedly, the structural position of the wells, structural framework, faults location, fold geometry, pore pressure changes and mechanical properties of rocks are main factors and have played an important role in stress condition and in situ stress regime in these two hydrocarbon structure.
Tectonics
Tahmoores Yousefi; Kooros Yazdjerdi; 2Manouchehr Ghorash; Alireza Shahidi
Abstract
Abstract: The brittle tectonic history expresses different tectonic events in the Zagros Simply Folded Belt. Consequence of Mesozoic extension, rifting and the shortening derived from the Cenozoic Eurasia – Arabia collision. In order to reconstruction the ancient tensions in the Mesozoic deposits ...
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Abstract: The brittle tectonic history expresses different tectonic events in the Zagros Simply Folded Belt. Consequence of Mesozoic extension, rifting and the shortening derived from the Cenozoic Eurasia – Arabia collision. In order to reconstruction the ancient tensions in the Mesozoic deposits in the east and south-east of Shiraz, geometry and kinematics of the faults data simultaneously with sedimentation was investigated using the inversion method, to evaluated rifting time, the former of Neo-Tethys and its collisions in Cretaceous and Paleocene. In this regard 21 stations have been exposed in Khanekat to Pabdeh Formations. The resulted geometry and kinematics of the faults data were calculated situation main tension axes (σ1, σ2, σ3 ), tension ellipsoid figure or ratio of difference (ɸ). The results are as follows: from Triassic to upper Cretaceous (Mastrichtian) in Khanekat,Surmeh, Fahlian, Darian, Sarvak, Ilam, Gurpi, Tarbur Formations and Ghorban Member; extensional tectonic regime was dominant and having NE-SW direction (N052°) but in Pabdeh Formation with Paleocene age, tectonic regime has changed into compression with NE-SW compressional stress direction(N045°). So it was concluded that in simply folded Zagros of interior Fars, time of rifting and the forming of Neo-Tethyan basin was Triassic or older (Permian) with NE-SW extensional direction. The beginning of compressional tectonic regime with the same direction has been in Paleocene.
Economic Geology
Behzad Hajalilou; M. Razmara; Nasim Hajalilou
Abstract
The placer ore deposit of Ataeieh is located in south west of Mashhad and central Iranian microplate. The petrography and mineralography studies of VTM placer ore deposit, showed that the main ores in this area from high to low amounts are: magnetite, titanomagnetite, hematite and ilmenite. It revealed ...
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The placer ore deposit of Ataeieh is located in south west of Mashhad and central Iranian microplate. The petrography and mineralography studies of VTM placer ore deposit, showed that the main ores in this area from high to low amounts are: magnetite, titanomagnetite, hematite and ilmenite. It revealed that the ultramafic and gabbros are the main source for opak minerals by mineralography Studies. The SEM-EDS, EPMA and XRM studies on the placer ore deposit and their origion presentaded remarkable results. The SEM investigation showed that, in the magma crystallization the solid soulution is formed between titanomagnetite and ilmenite at 800°C and then with the decreasing of temperature up to 600°C the ilmenite and magnetite exsolution lamella segreqates and separated from titanomagnetite phase either the ophiolite sequence is the source of this deposit. Titaniumand Vanadium enter to the ilmenite and titanomagnetite in gabbroic rocks whit continuing of magma crystallization. The EPMA analysis on gabbroic units showed that these rocks are origion for Ti and V in placers.
N Shahverdi; H Rahimpour- Bonab; M.R Kamali; B Esrafili- Dizagi
Abstract
The Albian-TuronianSarvak Formation is one of the main oil reservoirs in south and southwest Iran that hosts significant amount of hydrocarbon resources in this region. Facies analysis in seven oil fields of Persian Gulf led to identification of 7 microfaceis that are deposited in four facies belts in ...
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The Albian-TuronianSarvak Formation is one of the main oil reservoirs in south and southwest Iran that hosts significant amount of hydrocarbon resources in this region. Facies analysis in seven oil fields of Persian Gulf led to identification of 7 microfaceis that are deposited in four facies belts in a homoclinal ramp platform. Studies show that there is major facies variation in Sarvak carbonates of offshore Zagros. The rudist-bearing facies are mainly developed as major reservoir facies in the eastern Persian Gulf (Siri Fields) and replaced with mud-dominated lagoonalfacies in central and western sectors of considered area (Hendijan, Bahregansar, Balal and Lavan Fields). There are positive correlation between paleogeographic position of rudist buildups and configuration of Sarvak reservoir in the Persian Gulf. Main diagenetic processes that effected facies of this formation are neomorphism, bioturbation, micritization, dolomitization, dissolution, cementation, stylolitization and fracturing. During diagenesis, rudist-dominated facies are selectively dissolved and led to development porosity and reservoir quality in the Siri Fields. Generally, diagenesis is slightly impacted reservoir properties in the central and western parts oil fields, although, dolomitization is improved reservoir characteristics in the Bahregansar Field. Petrophysical evolution of studied intervals suggests that good reservoir intervals are associated with rudist-bearing facies. As well, there are decreasing trend in both porosity and permeability values from top of formation downwards, particularly in Siri fields. This trend is attributed to effect of meteoric diagenetic under the Turonian unconformity. In conclusion, our studies indicate that occurrence and evolution of rudists had main impact on diagenetic modification and reservoir potential of Sarvak Formation.
V. Hosseini toudeshki; M. Pourkermani; M. Arian; Kh. Khosrotehrani
Abstract
Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization ...
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Rivers are the most important landforms on the ground whose analysis is known as a useful tool in tectonic surveys in several thousands to two million years ago. The Ghezel Ozan River, the longest river system in the country, has responded to tectonic deformation thoroughly. Detection and characterization of geomorphic anomalies in the Ghezel Ozan River and correlation with structures can specify the role of structures in making active deformations. The intense and sudden deflection in the river course, the abnormal changes in the river sinuosity and knick points upon longitudinal profile of the river are the geomorphic anomalies connected to the structures. Deflection of the river course and abnormal changes in the river sinuosity are identified on the satellite images and approved through field observations. Knick points are specified upon longitudinal profiles of the river and the effects of lithology are surveyed in making of them٫ so that only knick points are considered which are produced by structures. Longitudinal profiles of the river have been obtained from digital elevation model. Above mentioned anomalies then have been correlated with structures extracted from geology maps and in this manner structures effective in making geomorphic anomalies have been identified. The study region is located in Sanandaj – Sirjan, Centeral Iran and Western Alborz zones. Around the Ghezel Ozan River, marl, sandstone, siltstone, limestone, tuff, agglomerate and volcanic rocks are extremely exposed. These rocks belong to Qom, Upper Red, Lower Red and karaj formations. Deflection of the Ghezel Ozan River is surveyed in the regions of Kuh-e-Palangi, Jelovdarlou, Cham and Yengejeh. Abnormal changes in river sinuosity is studied in regions of Jomaelou, Gol gheshlagh, Armoutlou, Kuh-e-Qaravol, Ghaflankuh and Kuh-e-Pajdar. In the regions of Sharif Abad, Iemir, Kuh-e-Qaravol and Kuh-e-Pajdar, knick points are specified upon longitudinal profile of the Ghezel Ozan River. The obtained results show that folds with trends of NW – SE and NE – SW have the highest influence on deflection of the course of the Ghezel Ozan River. The other geomorphic anomalies produced by faults with trends of NW–SE , NE – SW, N-S and E-W especially in instances that faults with trends of NW – SE and NE – SW have intersected. Thus, the most active structural trends in around of the Ghezel Ozan River are trends of NW–SE, NE – SW, N-S and E-W which correlate with trends of fractures in basement of Iran. In this way active folds and faults are identified in the area.
N. KhajehMohammadlo; E. Rasa; A. Emamalipur
Abstract
Alibaltalo bauxite deposit is situated in east Shahindezh, south west of west- Azarbaijan. This ore horizon lies along the boundary between Jurassic sandstone and Triassic dolomtite. In this study for understanding the chemical process involved in the formation of the bauxite deposite and in order ...
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Alibaltalo bauxite deposit is situated in east Shahindezh, south west of west- Azarbaijan. This ore horizon lies along the boundary between Jurassic sandstone and Triassic dolomtite. In this study for understanding the chemical process involved in the formation of the bauxite deposite and in order to determine the role and behavior of elements on weathering process, the gain and loss and mass transfer methods, enrichment -depletion diagrams were used. the result of this study diabase sills of Doroud Formation in the area is proposed as the principal source of this bauxitic horizon.. Mass change calculations for different elements compared to an immobile element (Titanium)- with. chemical stability in weathering processes. Results showed Si, Na, K, Mg, Ca depletion while Fe, Al, Ti showed secondary enrichment.The ore body shows decreasing in total mass of -21.02 for brown horizon,-21.02 for gray kaolinite layer,-22.91 for green to gray part and -23.55 for green to gray color horizon.
N. Abbassi; A. H. Amini
Abstract
The Upper Miocene Upper Red Formation in the Evan-e-Key Section is composed of conglomerates, sandstones, mudstones, and thin lenses of evaporates (gypsum). The formation is dominated by gypsiferous mudstones and characterized by fining-up cycles in this area. The whole ...
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The Upper Miocene Upper Red Formation in the Evan-e-Key Section is composed of conglomerates, sandstones, mudstones, and thin lenses of evaporates (gypsum). The formation is dominated by gypsiferous mudstones and characterized by fining-up cycles in this area. The whole formation occurs as a fining upward megasequence, in which the sandy facies dominate the lower half and muddy facies the upper half. Gypsum layers, up to 10 meters thick, are locally observed in the basal part. The formation has suffered an extensive weathering in the region, as a result of which primary features (e.g. sedimentary structures, trace fossils) are partially obscured. In the sandy units of the middle part of the formation some vertebrate footprints are observed, which are locally deformed due to intensive weathering of the rocks. Two types of Carnivoripedida footprints however, are distinguished and described here, so that well preserved Chelipus isp. is related to Felidae. Depositional environments including alluvial fans with abundant debris flows, gravelly bed load braided systems with wide flood plains and local swamps provided a good opportunity for development of the track makers. The transverse and longitudinal bars within the channels, levees, and over-bank sub-environments were found more suitable for development and preservation of the footprints. Comparing with other sections of the formation (e.g. Qum area), desirable climate was found a major control on development of the vertebrate track maker in the Evan-e-key area.
M. R. Sheykh Rabiee; S. Feiznia; H. R Peyrowan
Abstract
Soil erosion is one of the improper natural phenomenons. Soil erosion affects on soil degradation. To study and estimate sediment yield, there are several methods. Rainfall simulator is one of them. At this research, in first step, the work units map is prepared by overlying lithology, erosion and dip ...
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Soil erosion is one of the improper natural phenomenons. Soil erosion affects on soil degradation. To study and estimate sediment yield, there are several methods. Rainfall simulator is one of them. At this research, in first step, the work units map is prepared by overlying lithology, erosion and dip maps with together. At each work unit, 51 soil samples obtained in 17 stations. Volume of runoff and weight of sediment of each rainfall simulator test measured. The rainfall simulator was two kinds; one has rain surface 84 cm × 120 cm and the other one 25 cm × 25 cm. Every two kinds are adjustable in various dip degrees. The results in Hiv watershed showed that the highest producted runoff occurred in limestone and dolomite lithology with surface and rill erosion types at general dip more than 40 % and highest amount sediment yield is happened in sandstone lithology with surface and rill erosion types at general dip more than 40 %. With attention to the results and generalization of them to soil lose amount of Hiv watershed, for one rainfall event with 19 mm/h intensity at 30 minutes duration, the total soil lose of the watershed, 1057.74 ton is estimated
H. Inanloo Arabi Shad; F. Sereshki; M. Ataei; M.d Karamoozian
Abstract
Investigation of effective parameters on mechanical and physical properties of ore deposits is very important in determination of their rock mechanic and failure properties. This investigation can be suitable in different mining operations such as drilling, blasting, comminution and mine planning. In ...
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Investigation of effective parameters on mechanical and physical properties of ore deposits is very important in determination of their rock mechanic and failure properties. This investigation can be suitable in different mining operations such as drilling, blasting, comminution and mine planning. In this paper, at first, microscopic sections were studied under different lights in Chadormalu iron ore mine. Then geomechanical and seismic properties as well as failure behaviour of the oxide ores (magnetite and hematite) were studied. The results demonstrated that the percentage of magnetite has a direct relationship with uniaxial compressive strength, tensile strength, Young modulus and P and S wave velocities; and the magnetite percentage has an inverse relationship with Poisson's ratio, porosity and saturation. Finally, the relation between magnetite percent and blast-induced preconditioning was investigated. The results showed that increasing the percentage of magnetite will increase the blast-induced preconditioning and increasing preconditioning decreased comminution processes in the Chadormalu iron ore mine. Also increasing the percentage of magnetite in feed of process factory from 25 to 50% decreases the power consumption from 70 (KWh/t) to 40 (KWh/t).
M. Abdollahy; A. Raissi; H. Naderi
Abstract
An investigation on beneficiation of Lakhshak antimony ore was carried out using flotation methods. The grade of antimony in representative sample was 17.23%. The most important minerals were stibnite, quartz and pyrite and the degree of liberation of stibnite was found to be 700 micrometer. The raw ...
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An investigation on beneficiation of Lakhshak antimony ore was carried out using flotation methods. The grade of antimony in representative sample was 17.23%. The most important minerals were stibnite, quartz and pyrite and the degree of liberation of stibnite was found to be 700 micrometer. The raw material was divided into three size fractions and beneficiation of fine size fraction (-210+38 m) was floated. The grade of mentioned fraction was 20.50 %. Taguchi method was used in flotation tests and optimum conditions were determined as follows: CuSO4 (1700g/t) as an activator, potassium etyle xanthate (900 g/t) as a collector, MIBC as a frother, pulp density 22% and grain size -150+38 m. All the experiments were carried out at pH = 6.8. As a result the grade and recovery of antimony was obtained 38% (Sb) and 91% respectively.
Sedimentology
A. Rahimi; M. H. Adabi; A. Nabati; M. R. Majidifard; A. M. Jamali
Abstract
Carbonate sequences of the Shotori Formations (Middle Triassic) with a thickness of 308 m, were deposited in the Kalmard region of the Tabas city in Central Iran basin. The lower contact of the formation gradually and conformably overlies the Sorkhshale Formation and upper contact is faulted. The Shotori ...
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Carbonate sequences of the Shotori Formations (Middle Triassic) with a thickness of 308 m, were deposited in the Kalmard region of the Tabas city in Central Iran basin. The lower contact of the formation gradually and conformably overlies the Sorkhshale Formation and upper contact is faulted. The Shotori Formation is mainly composed of thick to medium bedded fine-coarsely crystalline dolomites with a thickness of 250 m with interbeds of thin bedded limestone and sandstone. The Shotori Formation is mainly composed of fine-coarsely crystalline dolomite. Based on petrographic (size and fabric), and elemental studies (Ca, Mg, Na, Sr, Fe, Mn), five dolomite types were recognized. Variation in dolomite types is mainly related to early to late diagenetic processes, changing the composition of dolomitizing fluids. Geochemical studies also indicate that medium to coarse grain dolomites formed in meteoric diagenesis under reducing conditions. Mechanism of dolomitization for dolomite type 1 is sabkha model, for dolomite types 2 and 3 is mixing zone and is burial model for dolomite types 4 and 5.
Remote Sensing
Mahya Nazarian; Mohammad Lotfi; Arash Gourabjeripour; Majid Ghasemi Siani
Abstract
The Chomalu Polymetallic deposit is located in western part of Alborz magmatic belt (Alborz-Azarbaijan) and central part of Tarom-Hashtjin metallogenic province. Eocene volcanic settings in the Chomalu deposit consist of basic rocks (olivinebasalt), intermediate (andesite basalt, andesite to trachyandesite) ...
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The Chomalu Polymetallic deposit is located in western part of Alborz magmatic belt (Alborz-Azarbaijan) and central part of Tarom-Hashtjin metallogenic province. Eocene volcanic settings in the Chomalu deposit consist of basic rocks (olivinebasalt), intermediate (andesite basalt, andesite to trachyandesite) and acidic rocks (dacite to rhyolite) which is intruded by quartz monzodiorite, monzosyenite and quartz monzonite intrusive rocks of Eocene. The main texture of volcanic rocks is more porphyritic. Olivine and plagioclase are the main phenocrysts in the olivinebasalt, andesite rocks compose of plagioclase and clinopyroxene and dacite to rhyolite consist of plagioclase, alkali feldspar and quartz. On the basis of AFM diagram, Chomalu volcanic rocks located in the high- K calc- alkaline to shoshonitic affinities in relation to subduction zone magmatism. Primitive mantle-normalized of volcanic rocks indicate that LILE enrichment and HFSE depletion in consistent with subduction zone magmatism. Chondrite-normalized REE patterns show LREE/HREE enrichment. Geochemical results suggesting primary source magmas source for volcanic rocks were generated by partial melting of the metasomatized lithospheric mantle-wedge in relation to subduction arc and were subsequently affected by both fractional crystallization and crustal contamination during magmatic evolution.
M. R. Moshrefi far; A. Alavi; M. Mohajjel
Abstract
In this research, separation of paleostress phases in the central part of Dehshir fault is investigated based on the study of heterogeneous fault-slip data and their related slickenside lineations. These data are measured from the Certaceous (Taft limestone), ...
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In this research, separation of paleostress phases in the central part of Dehshir fault is investigated based on the study of heterogeneous fault-slip data and their related slickenside lineations. These data are measured from the Certaceous (Taft limestone), early Eocene (Kerman conglomerate) and Eocene (Volcanics) formations. The main criteria used here to identify sense of fault-slip are stratiographic separation, accretionary mineral steps, Riedel shears and tension gash. The existing faults in the region of investigated often show two NE and NW trend in which the latter is usually dominant. Based on the study of heterogeneous fault-slip data and their related slickenside lineations and using the multiple inverse method, at least two phases are expected. These phases show that the axis of maximum principal stress, σ1, is at NE trend and that of minimum principal stress,σ3, is at NW trend. The location of σ3 usually indicates that the strike-slip and reverse strike-slip faults mostly occur in the region. In addition, the shape of the stress ellipsoid is prolate in the region.
S. Nezamvafa; M. Rezaee; R. Moussavi-Harami; M. Bargrizan; A. Chehrazi
Abstract
Investigation and detail recognition of hydrocarbon reservoirs can have a good help in management of production wells, and field development. Burgan formation is deltaic sandstone from lower-median Cretaceous that is divided into three zones, A, B, and C. This formation ...
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Investigation and detail recognition of hydrocarbon reservoirs can have a good help in management of production wells, and field development. Burgan formation is deltaic sandstone from lower-median Cretaceous that is divided into three zones, A, B, and C. This formation in its type section (Kuwait) makes the second biggest world reservoir, with up to 72 billion barrels of in situ oil. In this study, evaluation of reservoir parameters has been made for this formation. Volume of shale, porosity, permeability, saturation, determination of oil water contact (OWC), net/gross and hydrocarbon column thickness, are the main reservoir parameters, that have been calculated with deterministic and problistic method using different logs and core data of 36 wells.
All of these parameters in problistic method have been calculated by professional petrophysic software, Geolog. Results of calculations show that despite of B zone lower thickness; this zone has a very high reservoir quality than the other two zones. This high quality arises from clean sand and high porosity (intergranualr) and permeability of this zone. Higher thickness of Burgan formation and its reservoir zones in the west of study field, and reservoir high quality in these horizons, show that the original source of clastic sediments is form the Arabian Shield toward Iran.
Hydrology
Masoud Morsali
Abstract
Prediction of groundwater inflow into tunnels during excavation is one of the most important problems of tunneling projects. There are many analytical and empirical methods to predict the amount of groundwater entering the tunnels, which are generally not highly accurate. Permeability and water head ...
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Prediction of groundwater inflow into tunnels during excavation is one of the most important problems of tunneling projects. There are many analytical and empirical methods to predict the amount of groundwater entering the tunnels, which are generally not highly accurate. Permeability and water head are the main affecting parameters in estimation of groundwater inflow in current prediction methods. Due to the complexity of the geological and hydrogeological conditions of hard rock formations, it is necessary to enter other geological factors to estimate groundwater inflow into the tunnel. In this paper, for the first time, Geomorphological Rock Mass Strength (GRMS) classification is used as a criterion for estimating the groundwater entering the tunnel. The obtained data from two tunnels in different geological setting were used to study the effect of rock mass classification parameter on estimation of groundwater entering the tunnel. The results show that for both tunnels, GRMS have a significant correlation with the amounts of groundwater inflow into the tunnels.
M Tajbakhshian; M.H Mahmudy; A Mahboubi; R Moussavi Harami; I Ejlali
Abstract
Hydrogeochemistry of surface and ground waters is a useful way to identify performing reactions in aquifers and also in recognizing effective natural and anthropogenic polluting factors in these sources. In order to study surface and ground waters quality of shahid Hashemi- Nejad gas refinery region, ...
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Hydrogeochemistry of surface and ground waters is a useful way to identify performing reactions in aquifers and also in recognizing effective natural and anthropogenic polluting factors in these sources. In order to study surface and ground waters quality of shahid Hashemi- Nejad gas refinery region, located 35 km south of Sarakhs town, 17 water samples were collected. Parameters of pH, temperature, electrical conductivity and total dissolved solids were measured in the field, and water samples were analyzed for major anions and cations concentrations in geochemical lab. Using Piper diagram, sodium sulfate and sodium chloride type and facies were determined for the water samples. Ca2+/Mg2+v.as Mg2+ ,Ca2+/Ca2++Mg2+v.as SO42-/SO42-+HCO3- compound diagrams, total hardness and PCO2 proved carbonates dissolution. Na+/Na++Cl-, Ca2+/Ca2++SO42-,HCO3-/Σ anions, HCO3-/SiO2 , SiO2/Na++K+-Cl-, Na++K+and SO42-+Cl-ionic ratios determined factors such as ion exchange, dissolution of Gypsum, Halite and sulfates of sodium-potassium, and weathering of carbonates and silicates as the most important effective parameters on chemical composition of water sources in this area. In Log(aCa2+/a(H+)2)andLog(aMg2+/a(H+)2) v.asLog (aNa+/a(H+)2) diagrams, which are used for specifying soluble silicate minerals in water, all water samples showed the dissolution of Kaolinite except two samples which were located at clinochlore mineral zone. Calculating saturation indices using PHREEQC software proved that Calcite and Dolomite mineral had supersaturation, Halite and Anhydrite undersaturation and Gypsum mineral supersaturation, undersaturation and equilibrium states in all samples. Schoeller and Wilcox diagrams pointed unsuitable quality for drinking and agricultural usages for these water sources. In fact, because of formations presence with high solubility that lay out in large amount of surface, water resources in this area have not suitable quality, and on the other hand shallow water level and high temperature intensify it. Based on obtained results, natural factors have major role in quality area’s water resources.
K. Goshtasbi; M. Ahmadi; Y. Naeimi
Abstract
Locating the critical slip surface and the associated minimum factor of safety are two complementary parts in a slope stability analysis. A large number of computer programs exist to solve slope stability problems. Most of these programs, however, have used inefficient and unreliable search procedures ...
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Locating the critical slip surface and the associated minimum factor of safety are two complementary parts in a slope stability analysis. A large number of computer programs exist to solve slope stability problems. Most of these programs, however, have used inefficient and unreliable search procedures to locate the global minimum factor of safety. This paper presents an efficient and reliable method to determine the global minimum factor of safety coupled with a modified version of the Monte Carlo technique. Examples are presented to illustrate the reliability of the proposed method.
N. Haghipour
Abstract
Folded and faulted Kopeh Dagh-Binalud belt in the northeast of Iran is a part of Eurasia and southern margin of Touran plate. What is now observed is the result of the latest Phase of Alpine folding. The morphology of the area is in early stage and its young ...
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Folded and faulted Kopeh Dagh-Binalud belt in the northeast of Iran is a part of Eurasia and southern margin of Touran plate. What is now observed is the result of the latest Phase of Alpine folding. The morphology of the area is in early stage and its young folds express direct relevance between topography and geological structures. In order to evaluate uplift and distribution of compressional forces, stream- gradient (SL) and hypsometric (HI) analyses were carried out for 85 subbasins and 98 rivers of the major basins of the area (Atrakrud, Kashafrud, Jajarm, Gorganrud and Tourkamanestan plain rivers). Integration of the morphometric maps of SL and HI illustrates clearly the tectonic anomalies. Five highly uplifted morphotectonic zones were identified based on the morphotectonic indices as follows:
1) The middle part of Ashkabad Fault between geographical coordinates of: 56 47 E, 38 35 N to 57 34 E, 37 56N.
2) Gorganrud's sub-basins particularly located between Shavard fault (in the south) and eastern part of the Khazar fault (in the north).
3) Basins associated with Nokhandan, Qareh –Dagh, Sorkhdeh and Amrudak Faults.
4) Basins associated with Shogan and Gelli Faults are the Jajarm subbasins.
5) The northern foothill basins of BinaludMountain, compared with the southern foothill basins, show remarkable higher uplifting and shortening which seem to be related to the Binaloud and North Neyshabur fault.
In addition to high uplifted zones, some intermediate – low uplifted zones such as west - southwest part of Sarakhs, southern foothill subbasins of Atrakrud (associated with Takalkuh Fault and Ashkhaneh fault zone), Jajarm's subbasin in the eastern part of AladaghMountain were recognized.
M Raziani; M Vahidinia; A Sadeghi
Abstract
This study on the planktonic foraminifera of the Surgah Formation was carried out .three biozones are proposed for the Late Turonian – Early Santonian interval in Surgah anticline (Southwest Ilam).Based on planktonic/benthonic foraminiferal ratios and “van der zwaan” equation, a general ...
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This study on the planktonic foraminifera of the Surgah Formation was carried out .three biozones are proposed for the Late Turonian – Early Santonian interval in Surgah anticline (Southwest Ilam).Based on planktonic/benthonic foraminiferal ratios and “van der zwaan” equation, a general deepening of depositional environment is indicated from Late Turonian – Early Santonian ages.During the early late Turonian, A (deeper) upper bathyal environment of about 1000 m water depth is indicated (96-98 % planktonic foraminifera, with a relatively large number of keeled and non – keeled specimens).The middle late to latest Turonian interval is characterized by 70 – 90 % planktonic foraminifera with keeled specimens dominating and rarely none – keeled and very rarely heterohelix, pointing to an upper bathyal depositional environment ( 500 m water depth), eutrophication to oligotrophication conditions. During early Coniacian , water depth falling slowly and characterized by 65 – 80 planktonic foraminifera with keeled forms dominating, oligotrophication conditions.Then in late Coniacian water depth rising (1000 m water depth), none – keeling dominating that pointing to eutrophication conditions. A (shallow) upper bathyal environment (400 m water depth), dominated by keeling foraminifera, oligotrophication condition, during the early santonian, is indicated by 45-60 % planktonic foraminifera but there are a short time of raising water depth before upper surgah that is indicated by 90% planktonic foraminifera, with dominated by none-keeling foraminifera specimens, eutrophication condition. In general, an open marine deep water environment (upper bathyal) is indicated by the Late Turonian to early Santonian planktonic foraminiferal faunas, influenced by periods of eutrophication to oligotrophication repeatedly.
Sedimentology
Umid Kakemem; Mohammad Adabi; Ehsan Dehyadegari
Abstract
Depositional texture, sedimentary structure and present fauna led to characterize twelve carbonate- evaporate facies. These facies were classified in three facies belts including tidal flat, lagoon and shoal. Developpment of tidal zones together with evaporate deposits and thrombolite facies (signs to ...
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Depositional texture, sedimentary structure and present fauna led to characterize twelve carbonate- evaporate facies. These facies were classified in three facies belts including tidal flat, lagoon and shoal. Developpment of tidal zones together with evaporate deposits and thrombolite facies (signs to a shallow depositional environment), the absence of continuous reef‐frame builders, high production of carbonate mud, absents of calciturbidite, tempestites deposits and slump structures are evidences for a homoclinal carbonate ramp setting. The facies based on petrophysical characteristics which is the results of depositional texture and diagenesis are classified in seven reservoir rock types. In which, the first rock type (RT1) has weak reservoir property and toward RT7 reservoir quality will increase. Facies variation related to sea level fluctuations led to subdivide the whole strata into two 3rd order sequences. Facies stacking patterns in the sequences characterized by subtidal facies (lagoon and shoal) tend to have the most reservoir quality that covered by evaporative (Mf1) and peritidal facies (Mf2 to Mf4) with low-reservoir quality. The most reservoir quality in both K1 and K2 reservoir zones is coincident with late TST, maximum flooding surface (mfs) and late HST in identified depositional sequences which is settled in high-energy shoal facies intervals.
