Original Research Paper
Geological Environment and Engineering
Neda Khajooee; Sourosh Modabberi; Behnoush Khosh manesh zadeh; Fatemeh Razavian
Abstract
Population growth and increasing urbanization expose people to higher degrees of urban pollutants, especially when they need to spend long time in enclosed environments with inadequate ventilation. This study is the first research on inorganic pollutants in indoor dust particles of Tehran city, which ...
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Population growth and increasing urbanization expose people to higher degrees of urban pollutants, especially when they need to spend long time in enclosed environments with inadequate ventilation. This study is the first research on inorganic pollutants in indoor dust particles of Tehran city, which applies geochemical indices to estimate the intensity of dust pollution by potentially toxic elements. A number of 31 indoor dust samples were passively collected from inside the residential and office buildings in the central and densely populated districts of the city and were analyzed by ICP-Ms at the Taragona University of Spain. Single geochemical indices of Contamination Factor, Geoaccumulation Index, Enrichment Factor, and cumulative indices of Pollution Load and Potential Ecological Risk Indices were calculated. The results of elemental analysis showed that the concentration of arsenic, cadmium, copper, mercury, lead and zinc in Tehran indoor dust is higher than that in some cities in the world. On the other hand, cobalt, chromium, nickel and vanadium present low concentrations in the analyzed indoor dust samples. This result was confirmed by the cumulative indices as well as the contamination factor. In contrast, some other factors showed low to medium degree of pollution for the above-mentioned elements.
Original Research Paper
Petrology
Afsaneh Naseri Esfandagheh; Mohammad Rahgoshay; Sasan Bagheri
Abstract
The Haji-Abad-Esfandagheh-Faryab ophiolitic belt is one of the most famous chromite-bearing occurrences in the south of Iran. In recent years, the ophiolitic belt of Haji-Abad-Esfandagheh-Faryab has been the focus of attention of many geologists interested in ophiolitic complexes and economic geology. ...
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The Haji-Abad-Esfandagheh-Faryab ophiolitic belt is one of the most famous chromite-bearing occurrences in the south of Iran. In recent years, the ophiolitic belt of Haji-Abad-Esfandagheh-Faryab has been the focus of attention of many geologists interested in ophiolitic complexes and economic geology. Golashkard ultramafic unit includes dunite, highly serpentinized harzburgites, chromitite and wehrlite layers in the Faryab ophiolitic complex located in the southeast of Sanandaj-Sirjan as one of the chromite-bearing areas of the Haji-Abad-Esfandagheh-Faryab ophiolitic belt. Ultramafic rocks and chromitites of Golashkard area consist of 20 to more than 50% of chromite. The studied chromites have variable massive, banded and scattered textures. The geochemistry of Golashkard ultramafic rocks shows that the average Cr# enrichment of chromite in serpentinite rocks (probably dunite and harzburgite) and wehrlite is to Cr/ (Cr + Al) ×100= 70-80 and in chromitite is relatively higher (Cr/ (Cr + Al) ×100= 81). Based on the lithological and mineral chemistry characteristics, Golashkard ultramafic rocks are part of mantle related to ophiolite, which was produced by a homogeneous boninitic melt in the suprasubduction zone and formed high chromium chromitites and related peridotites.
Original Research Paper
Sedimentology
Hoda bavi; Reza Moussavi-Haramia; Mohamad Hosein Mahmudy Gharaie; Hamed Zand-Moghadam; Asadollah Mahboubi; Mohammad Reza Tohidi
Abstract
The geochemical separation pattern and environmental behavior of ΣREE have been investigated in five different sedimentary systems related to Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using multi-acid digestion ...
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The geochemical separation pattern and environmental behavior of ΣREE have been investigated in five different sedimentary systems related to Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using multi-acid digestion and mBCR selective extraction method. The normalization patterns of ΣREE are drawn based on the NASC and UCC. concentration changes in the five sedimentary systems are very similar and the concentration of LREEs is higher than that HREEs, Opposite of the changes in the concentration of ΣREEs, more enrichment is seen in HREEs compared to LREEs. The geochemical separation patterns of ΣREEs in natural sediment and samples containing iron and manganese oxides is mainly dominated by the residual fraction. considering the different conditions of formation and stability in the samples taken from the waterways leading to the mine, evaporite deposits and sediments washed from the rock dump, the separation pattern of ΣREEs is controlled mainly with two parts soluble in Acid and reducible fraction. The trend of mobility and bioavailability from LREEs to HREEs increases with an upward slope. These results show that speciation, geochemical segregation pattern and environmental behavior for ΣREE lead to misinterpretation without considering key environmental factors.
Original Research Paper
Sedimentology
Sedigheh Amjadi; Hamid Alizade Lahijani; Mohamad Hosein Mahmudy Gharaie; Razieh Lak; Nick Marriner
Abstract
AbstractAlthough the second deadliest tsunami in the Indian oceans was triggered in the Makran zone, our knowledge in regard to the number of tsunami events through the Holocene is negligible. In this study the sedimentary environment palaeo-tsunami have reconstructed and identified by Gulf of Oman deep ...
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AbstractAlthough the second deadliest tsunami in the Indian oceans was triggered in the Makran zone, our knowledge in regard to the number of tsunami events through the Holocene is negligible. In this study the sedimentary environment palaeo-tsunami have reconstructed and identified by Gulf of Oman deep sea cores. Sedimentation trends and effective factors on seabed sediments transportation by tsunami events were identified based on sedimentological parameters, foraminifera shells identification, magnetite susceptibility changes and palaeo-ocean currents reconstruction. The results of this study demonstrated that evidence of sea bed sediments transportation due to the strong earthquake in the Gulf of Oman were different through time and location. The palaeoenvironmental studies and historical tsunami events suggested at least five considerable submarine landslides through last 2500 cal. yr BP. The number of the events have dramatically increased during last thousand years. Rendering to the results and historical data, almost seven strong earthquakes were happened in the studied area that their traces have illustrated in this study. According to the city expansion in the southeast coast of Iran and increases number of earthquake events in the Makran zone adoption management plans in order to decrease probably tsunami damages are required.
Original Research Paper
Geological Environment and Engineering
Amir Mahyar azhdarpour; Mohammad Reza Nikudel; Mashalah Khamehchiyan
Abstract
The central Alborz structural-sedimentary area in the middle part of the Alborz Mountain range has endured geological events from the Precambrian to the present era, and contains numerous geological structures and formations. Among these, sandstone formations also have a significant expansion. In this ...
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The central Alborz structural-sedimentary area in the middle part of the Alborz Mountain range has endured geological events from the Precambrian to the present era, and contains numerous geological structures and formations. Among these, sandstone formations also have a significant expansion. In this research, six different sandstone formations were sampled in two locations and tested to determine their physical and mechanical characteristics.In general, in the sandstone formations of central Alborz, top quartzite has stronger mechanical parameters than other formations. Shamshak Formation has the lowest mechanical parameters among the selected formations. Based on regression analysis, the conversion factor of PLT, BST and CPI parameters to unconfined resistance or UCS showed 20.6, 6 and 20.40 respectively with R2s of 0.75, 0.90 and 0.78.In terms of the Abundant Index (CAI) as an index that can show the amount of abrasion, Top quartzite has the most abrasiveness, which is due to its lithological composition. This sandstone formation is placed in the category of stones with high abrasive ability, and Shamshak formation has the lowest rich index among the formations and is placed in the group of stones with extremely low abrasiveness
Original Research Paper
Economic Geology
Leila Amini; Mohammad Maanijou
Abstract
One of the common processes that lead to the formation of and enrichment of precious metal deposits is boiling. The existence of a spatial relation between fluid boiling and deposition of precious metals is a valuable tool in exploration of epithermal deposits. Therefore, investigating the occurrence ...
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One of the common processes that lead to the formation of and enrichment of precious metal deposits is boiling. The existence of a spatial relation between fluid boiling and deposition of precious metals is a valuable tool in exploration of epithermal deposits. Therefore, investigating the occurrence of this process will be able to predict the continuation of exploration trend. ChahMorad epithermal deposit is 75km northwest of Bazman in the Sistan-and-Baluchistan Provinces and is in the Makran-Chagai Magmatic Arc southeast of Iran. The mineralization in the ChahMorad deposit occurred in 3 stage and in quartz veins that exist between the altered argillic alteration zone and dacite and rhyodacite sub-volcanic rocks. Textural mineralogical and fluid inclusions studies indicate the occurrence of the boiling process in this deposit. The most important kinds of evidence for the occurrence of this process are (a)the presence of adularia, (b) platy calcite texture, (c)breccia, crustiform-colloform textures, (d)different liquid-vapor ratios of fluid inclusions, (e)the increase in the salinity of fluid inclusions with the decrease in homogenization temperatures, (f)the coexistence of fluid inclusions with different salinities and (g) coexisting liquid single-phase fluid inclusions with vapor fluid inclusions single-phase. Therefore, existing of boiling is confirmed in the ChahMorad deposit.
Original Research Paper
Tectonics
mohammadreza sheikholeslami
Abstract
Ten tectono- sedimentary basins have been identified around the Paleotethys suture zone in NE Iran. These basins have been developed from the Lower Paleozoic to recent time in response to relative movements of the of Eurasia and Gondwana supercontinents. The recognized basins from ancient to modern are: ...
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Ten tectono- sedimentary basins have been identified around the Paleotethys suture zone in NE Iran. These basins have been developed from the Lower Paleozoic to recent time in response to relative movements of the of Eurasia and Gondwana supercontinents. The recognized basins from ancient to modern are: (1) Paleozoic passive marginal basin of central Iran, (2) Devonian-Carboniferous platform basin of Turan plate, (3) active continental margin basin (trench and foreland), (4) Permo-Triassic arc-related basins, (5) Upper Triassic-Lower Jurassic peripheral foreland basin, (6) Lower to Middle Jurassic intramontane basin, (7) Middle Jurassic rift basin, (8) Oligocene-Pliocene foreland basin and (10) post orogenic molasses basin. Each basin has its own characteristics, and is formed in different tectonic setting during the evolution of the Paleotethys Ocean in NE Iran.
Original Research Paper
Sedimentology
Shirin Samani; A. Uromeihy; Amirhossein Enayati; Imandokht Mostafavi; Misha Pezeshki
Abstract
Diagenetic processes in carbonate rocks can be considered as one of the most important factors influencing the inherent characteristics of this type of reservoir on a small as well as large scale. Considering the importance of knowing the mechanical characteristics of reservoir rocks in geomechanical ...
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Diagenetic processes in carbonate rocks can be considered as one of the most important factors influencing the inherent characteristics of this type of reservoir on a small as well as large scale. Considering the importance of knowing the mechanical characteristics of reservoir rocks in geomechanical modeling and its application in the exploitation-development of hydrocarbon fields, it is necessary to find out how lithological characteristics affect its rock mechanical behavior. In this study, the impact of two diagenetic processes (Dolomitization and Anhydrite cement) on the physical and mechanical characteristics (such as Uniaxial Compressive Strength, Young’s modulus, Cohesion, and Internal friction angle) of carbonate reservoirs of the Kangan Formation, are addressed. The evaluations have been done in two phases: i.e. lithological studies and rock mechanical tests. The results show that changes in mechanical properties are strongly influenced by diagenetic processes. The two main influential features on mechanical characteristics are dolomitization and anhydrite cementation, which strongly affect porosity, dominant pore type, and mineralogy. The results show that dolomitization in the studied samples has caused an increase in porosity and a decrease in strength and elasticity. While the presence of anhydrite has caused an improvement in the resistance characteristics with an opposite effect.
Original Research Paper
Economic Geology
Mohsen Rezaei; Alireza Zarasvandi; Sima Basious
Abstract
Iju porphyry deposit is associated with the emplacement of Miocene tonalite-granodiorite intrusions (zircon U/Pb dating; 9.27±0.50) within Eocene volcanic and pyroclastic sequences including andesite, basaltic andesite, trachyandesite, andesitic breccias, tuffaceous breccias, and agglomerate. ...
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Iju porphyry deposit is associated with the emplacement of Miocene tonalite-granodiorite intrusions (zircon U/Pb dating; 9.27±0.50) within Eocene volcanic and pyroclastic sequences including andesite, basaltic andesite, trachyandesite, andesitic breccias, tuffaceous breccias, and agglomerate. In this study, occurrence and chemistry of magnetites in the potassic alteration of Iju deposit were assessed using EMPA analysis. The findings imply for a limited occurrence of magnetite as fine-grained disseminated and/or product of biotite chloritization. Magnetites associated with potassic alteration of Iju deposit don’t show hematite intergrowth (as martitizied margin) and anhydrite paragenesis, indicating the lack of high oxygen fugacity (near magnetite-hematite buffers; ~ΔFMQ+4) during the magnetite crystallization in the potassic alteration. Studied magnetites are high temperature (>500 °C) and according to the Mg + Al + Si contents crystallized under low rate of fluid rock interaction. These evidences accompanied with the absence of reequilibration processes could imply for the lack of repeated stages of hydrothermal fluid exsolving during the evolution of potassic alteration in the in the Iju deposit. Additionally, results represent that there are a considerable values of Ga (average; 0.015 wt. %) in the studied magnetites providing insights into the presence of unseen exploration potentials associated with porphyry Cu deposits of UDMB.
Original Research Paper
Stratigraphy and Palaeontology
Nasrollah Abbassi; Safoora Shakeri; Javad Rabbani
Abstract
Numerous Proboscidean footprints have been discovered in the outcrop (135 m) of lower rock unit of the Upper Red Formation (Middle-Late Miocene) in the north Avaj (Qazvin province), central Iran. These footprints are preserved as circular concave epi-relief in the upper bedding plans with smooth or levee ...
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Numerous Proboscidean footprints have been discovered in the outcrop (135 m) of lower rock unit of the Upper Red Formation (Middle-Late Miocene) in the north Avaj (Qazvin province), central Iran. These footprints are preserved as circular concave epi-relief in the upper bedding plans with smooth or levee rims or with sediment accumulation in the front of the footprints. Five digit imprints present in some of the footprints. The frequency of footprints is considerable the most of the upper surface of layers which resulted by movement of proboscis herds. Ichnotaxonomically these footprints identified as Proboscipeda enigmatica. The footprints are classified as two size small (15 cm) and large (25 cm) categories, and based on the geometric relationships, the height of shoulder was estimated as 140-170 cm for adult and 76-106 cm immature individuals. According to reports of Miocene Proboscidean body fossils form Iran, and based on the distributions of the Proboscidean in this time, it seems that the Choerolophodon (Gomphotheriidae) is candidate as track-maker of the Avaj footprints. Among the Proboscidean footprints, there are crocodile and fish swimming imprints which were left in the shallow pools.
Original Research Paper
Stratigraphy and Palaeontology
Hamta Ranjbar; Abbas Ghaderi; Hossein Gholamalian; Vachik Hairapetian
Abstract
Middle Devonian to Lower Carboniferous siliciclastic-carbonate successions in Eastern Alborz are characterized by Khoshyeilagh Formation. It is underlain by the Devonian red siliciclastic sequences and is overlain by the Carboniferous Mobarak Formation, can be divided into three different members; lower ...
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Middle Devonian to Lower Carboniferous siliciclastic-carbonate successions in Eastern Alborz are characterized by Khoshyeilagh Formation. It is underlain by the Devonian red siliciclastic sequences and is overlain by the Carboniferous Mobarak Formation, can be divided into three different members; lower carbonate, middle siliciclastic, and upper carbonate. The Khoshyeilagh Formation comprises various fossil groups of invertebrates, conodonts, palynomorphs and fish remains. In the present study, a collection of microscopic fish remains, obtained from the lower and upper carbonate members in Mighan, north of Shahrood, have been determined and described. This assemblage contains 14 different taxa of chondrichthyan fish including: Cladodoides cf. wildungensis, Ctenacanthiformis gen. et sp. indet, Dalmehodus turnerae, Deihim mansureae, Lissodus lusavorichi, Phoebodus aff. turnerae, Phoebodus fastigatus, Phoebodus gothicus gothicus, Phoebodus gothicus transistans, Roongodus phijani, Siberiodus mirabilis, Squatinactis glabrum, Stethacanthus resistens and Thrinacodus ferox. Some specimens of scales and teeth of actinopterygian and osteichthyan fishes are also present which all indicate a shallow environment of the continental shelf. The associated conodonts with this assemblage demonstrate the age of Frasnian (rhenana biozone) to early Tournaisian (duplicata biozone) for the whole succession.
Original Research Paper
Tectonics
Zahra Tavazo; Ebrahim Gholami; Hossien motamedi; Bahman soleimany
Abstract
: Numerous mechanisms are active during folding in folded-thrust belts, such as the role of salt movement, the role of multiple detachments in sedimentary cover, interference between different phases of deformation, and the role of basement during folding. In this research, such structures have been ...
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: Numerous mechanisms are active during folding in folded-thrust belts, such as the role of salt movement, the role of multiple detachments in sedimentary cover, interference between different phases of deformation, and the role of basement during folding. In this research, such structures have been introduced and studied in Takhteh, Nahreh and Kuh-e- Lar anticlines in the north of Fars Paleo high during field observations .These structures mainly include growth strata, geometry of tectonic synchronous strata, structures associated with shallow detachment such as rabbit ear structures, faults that are themselves structures that control the geometry and kinematics of structures, and sulfur springs that related to faults and rheology of exposed formations. The present study shows that the anticlines have an aspect ratio less than ten and are part of the detachment folds in which the detachment horizons have played a role and have a dextral arrangement. The formation of these anticlines occurred at the same time, which will be connected to each other, and these anticlines are associated with basement faults. The location of these anticlines is suitable for the presence of hydrocarbons but the basement fault in the southern flank of Takhteh anticline may affect the reservoir.
Original Research Paper
Sedimentology
Ali Hossein Jalilian; Mohammad Ali Kavoosi
Abstract
The Hauterivian-Barremian Gadvan Formation represents the depositional sequence in central and eastern regions of Zagros Mountains. Field and petrographic investigations of this formation in Khaneh-Kat anticline togheter with wireline logs and cuttings analysis of two drilled wells in the Dashtak and ...
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The Hauterivian-Barremian Gadvan Formation represents the depositional sequence in central and eastern regions of Zagros Mountains. Field and petrographic investigations of this formation in Khaneh-Kat anticline togheter with wireline logs and cuttings analysis of two drilled wells in the Dashtak and Bandubast gas fields (Interior Fars area) indicate important events in the basin evolution, especially the changes in the sedimentation regime and platform evolution during the time period. The key point is upward grading of the thick-bedded, feature forming Berriasian-Valanginian carbonates into shale, marl and argillaceous limestone interbeds of the Gadvan Formation. The vertical changes is consisten with a prominent decrease in carbonate production and a definite change in the nature of the Fars platform. The intense bioturbation and mostly mud-dominated texture of skeletal limestones indicate Gadvan Formation deposited in a mixed carbonate-siliciclastic platform. In the drilled wells, these changes correspond to a significant increase in gamma-ray and sonic wireline logs. The Khalij Member shows the regional continuity, indicates an increase of carbonate production in the mixed platform. Considering tectonic quiescence of Fars area during Early Cretaceous, the mentioned changes can be the result of interplay between tropical climate and short-term fluctuations in the context of global sea level rise.
Original Research Paper
Stratigraphy and Palaeontology
Toran Khamohi; Ahmad Lotfabad Arab; Mohamadreza Vaziri Vaziri
Abstract
In order to fossils study of Lower Cretaceous deposits, the Baghin section was chosen and sampled. This section consist of a sequence of green marl, limestone and shaly limestone deposits. In this section, diverse groups of microfossils (orbitolinids, algae and ostracods) and macrofossils (corals, echinoids, ...
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In order to fossils study of Lower Cretaceous deposits, the Baghin section was chosen and sampled. This section consist of a sequence of green marl, limestone and shaly limestone deposits. In this section, diverse groups of microfossils (orbitolinids, algae and ostracods) and macrofossils (corals, echinoids, bivalves, brachiopods, gastropods,…) are present. The presence of diverse collection fossils, especially large orbitolinid foraminifera indicated a favorable environmental conditions and absence of planktonic foraminifera indicated a shallow environmental conditions. Also, the presence of platycopid and podocopid ostracods and corals confirm the shallow, warm, light and suitable paleoecological conditions.Key words: fossils study, Orbitolinid, Ostracod, Coral, Baghin , Kerman.
