علمی -پژوهشی
Shiva Meskini Siahmard
Abstract
معدن مس قیصری در 105 کیلومتری جنوب شهرستان دامغان در استان سمنان، در انتهای غربی نوار آتشفشانی- رسوبی ترود- چاه شیرین و بخش شمالی پهنه ساختاری- رسوبی ایران مرکزی واقع شده ...
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معدن مس قیصری در 105 کیلومتری جنوب شهرستان دامغان در استان سمنان، در انتهای غربی نوار آتشفشانی- رسوبی ترود- چاه شیرین و بخش شمالی پهنه ساختاری- رسوبی ایران مرکزی واقع شده است. کانسنگهای منطقه کالکوسیت، کوولیت، پیریت، دیژنیت، مالاکیت، آزوریت و مس خالص همراه با کانیهای آهن ازجمله هماتیت، گوتیت، مگنتیت و لیمونیت هستند. سنگهای میزبان کانهزایی شامل بازالت و آندزیت و سنگهای آذرآواری از جمله توف و آگلومرا با ترکیب مشابه، به سن ائوسن، سنگهای میزبان کانهزایی مس منطقه میباشند. روند عمومی واحدهای میزبان شمالغربی- جنوب شرقی با شیب به سمت جنوبغرب است که توسط یک دایک با روند شمالشرقی- جنوبغربی قطع شده است. کانهزایی مس به شکل شکافهپرکن در طرفین دایک به طول بیش از یک کیلومتر و عرض حدود 20 متر رخ دادهاست. دگرسانیهای مشاهده شده در منطقه عبارتند از: کلریتی، آرژیلیتی، سریسیتی، سیلیسی، کربناته و اکسیدهای آهن. براساس تبعیت کانهزایی شکافهپرکن در طرفین دایک، کانیشناسی ساده و دگرسانیهای اطراف آن میتوان نفوذ دایک دیابازی را عامل اصلی حرارتی در کانهزایی دانست. در منطقه قیصری این دایک دیابازی بهعنوان یک کلید اکتشافی محسوب میشود. بر این اساس بخش جنوب و جنوبغرب منطقه، توسط آبرفت، دایک و کانهزایی مس قابل شناسایی میباشد. بر پایه مطالعات انجام شده احتمالا⸗ خواستگاه مس محلولهای هیدروترمال دما پایین بوده که سبب شستشوی مس از سنگهای آتشفشانی با ترکیب آندزیت و بازالت و تهنشست آنها در شکستگیهای موجود در سنگهای میزبان شده است. براساس بررسیهای ژئوشیمیایی گدازهها به سری آهکی- قلیایی پتاسیم بالا وابستهاند، که در یک حاشیه فعال قارهای تشکیل شده است.
علمی -پژوهشی
iman Araadfar; Mohammad hossein Zarrin koub; سید سعید محمدی; ابراهیم غلامی; Sun-Lin Chung; afsaneh Rashidpoor
Abstract
تودههای گرانیتوئیدی سِیدال در 150 کیلومتری جنوب شرق بیرجند در مرز شمال غربی زون جوش خورده سیستان در شرق ایران رخنمون دارند که واحدهای افیولیتی و دگرگونی منسوب به کرتاسه ...
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تودههای گرانیتوئیدی سِیدال در 150 کیلومتری جنوب شرق بیرجند در مرز شمال غربی زون جوش خورده سیستان در شرق ایران رخنمون دارند که واحدهای افیولیتی و دگرگونی منسوب به کرتاسه فوقانی را قطع کردهاند. این تودهها دارای فازهای گرانودیوریت، مونزوگرانیت و سینوگرانیت میباشند. گرانودیوریت بهصورت یک توده نفوذی کشیده با امتداد شمال غرب - جنوب شرق به عنوان توده اصلی و تودههای مونزوگرانیت و سینوگرانیتی به صورت تودههای کوچک، در مرز واحد گرانودیوریت و اولترامافیک مشاهده میشوند. کانیهای تشکیل دهنده این سنگها شامل کوارتز، پلاژیوکلاز، پتاسیم فلدسپار، بیوتیت، آمفیبول، اسفن، آپاتیت، زیرکن، گارنت و مسکویت هستند. بافت غالب این سنگها گرانولار و به ندرت پرتیتی و میرمکیتی است. توده گرانودیوریتی متاآلومین و تودههای مونزوگرانیت و سینوگرانیتی پرآلومین و کالک آلکالن می باشند. غنی شدگی از عناصر لیتوفیل بزرگ یون (LILE)و بالا بودن نسبت عناصر نادر خاکی سبک به سنگین (LREE/HREE) به همراه آنومالیهای منفی از عناصر با شدت میدان بالا (HFSE) مانندNb ,P وTi در واحد گرانودیوریتی حاکی از تعلق آنها به گرانیتوئیدهای نوع I و کمان ماگمایی(VAG) است. تودههای مونزوگرانیت و سینوگرانیتی آنومالی منفی P ,Ti ,Ba ,Srو Nb و آنومالی مثبت La ,Th ,Rb ,Kو Ce دارند که نشان از منشأ گرفتن این سنگ ها از پوسته قارهای است و در جایگاه تکتونیکی برخورد قارهای(syn-COLG) و همچنین در گروه گرانیتهای نوعS قرار میگیرند. سن سنجی به روش زیرکن - اورانیوم - سرب، سن توده گرانودیوریتی را 7/0±3/54 میلیون سال (اوایل ائوسن) تعیین نمود. منشأ تودههای نوع I در محدودهی آمفیبولیت و نوعS در محدودهی مذابهای حاصل از رسوبات پلیتی تصویر شدهاند که نوع I میتواند در ارتباط با فرورانش رخ داده درخاور ایران و نوع S از برخورد دو بلوک قارهای لوت و افغان بوجود آمده باشد.
Original Article
Geology
Elahe Taheri; Ebrahim Gholami; Ali Yassaghi
Abstract
Tuyeh-Darvar mountains are located in southern flank of the eastern Alborz and due to a relatively complete stratigraphy sequences from Paleozoic to Cenozoic are a suitable location for analysis on structural evolution over the southern slope of eastern Alborz. The Giv Fault ,as the southern boundary ...
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Tuyeh-Darvar mountains are located in southern flank of the eastern Alborz and due to a relatively complete stratigraphy sequences from Paleozoic to Cenozoic are a suitable location for analysis on structural evolution over the southern slope of eastern Alborz. The Giv Fault ,as the southern boundary of the mountains, is the region main thrust. The high angle Giv Fault with reverse mechanism controls the outcrop of Jurassic rocks to the south and therefore considered as the initial normal fault bounds the sedimentary basin, which underwent tectonic inversion during the Cretaceous-Paleocene. Inversion of the fault to the revers kinematics has been associated with the formation of the Mila Fault as its hanging wall back-thrust with greater reverse displacement. The tectonic inversion process of the Giv Fault has also been associated with the development of Tuye and Darvar hanging wall thruts and has caused the Tuyeh-Darvar mountains to be formed as a pop-up structure where Paleozoic units as Hanging wall anticlines thrus over younger units ones.
علمی -پژوهشی
pouria salami; afshin akbarpour; mohammad lotfi; arash gourabjiri
Abstract
XVI-B anomaly iron ore deposit is located in Iran-Central structural zone in Bafq area. Based on geological knowledge the oldest rocks in this area are Precambrian metamorphosed units like genaiss, mica-schist, amphibolite and migmatite that formed bedrocks for this mineralization anomaly. The mineralization ...
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XVI-B anomaly iron ore deposit is located in Iran-Central structural zone in Bafq area. Based on geological knowledge the oldest rocks in this area are Precambrian metamorphosed units like genaiss, mica-schist, amphibolite and migmatite that formed bedrocks for this mineralization anomaly. The mineralization area is completely covered by a series of Tertiary and Quaternary sediments of Bafq Basin. Mineralization intrusion mass units are specified by alkaline diorites-syenites. This deposit contains a variety of igneous, metamorphic and metasomatic rocks. Based on the petrographic view, igneous rocks are granitoid that are include: gabbro, syenite, quartz monzonite, granite, and highly altered basaltic rocks (metabasite). The metamorphic rocks are marble, epidote actinolite, actinolite (metasomatic rocks) and skarn rocks. Metallic mineralization has occurred in relation to syenite, gabbro and skarn rocks. Magnetite is the most abundant iron oxide ore in this anomaly and it can be seen with aggregate, ribbon, fill in the void and spray texture and its pieces are shaped to be amorphous. Magnetite is oxidized near the surface and is altered to hematite, goethite, and other iron oxides. Other metallic minerals participants with magnetite are pyrite and chalcopyrite that can be seen with quartz, actinolite, calcite, and epidote in various forms within host rocks, syenite intrusions, gabbros, and skarns. Accordance with rare element diagrams in iron mineralization and intrusive masses, which indicates the origin of mineralization is similar to intrusive masses probability. Iron oxide grade varies between 5 and 75 percent in the ore. The iron element has a negative correlation with titanium, magnesium, manganese, phosphorus, potassium and sodium oxides. Based on cobalt to nickel, chromium to nickel, chromium to vanadium relationship, this iron deposit is placed in the hydrothermal deposits range. Due to the Al / Co and Sn / Ga ratios, this deposit is located within the skarn type deposits. Based on the scattering patterns of trace elements XVI-B anomaly iron ore is more similar to the skarn type deposits. Geological, mineralogical and geochemical evidence of magnetite indicates skarn origin for iron mineralization of XVI-B anomaly. This means that iron is displaced by hot fluids from the intrusive masses and accumulates in the interval between the metamorphic units and marble.
علمی -پژوهشی
Geology
Hadi Mohammadian; Ali Asghar Calagari; Ali Asghar Calagari; vartan simmonds; Kamal Siahcheshm
Abstract
The Niaz copper prospect is located in west of Meshginshahr, east of Gharehdagh mineralization zone. The lithologic units in this area include intermediate igneous sub-volcanic (granodiorite, quartz monzonite, quartz monzo-diorite) and pyroclastic rocks. In terms of magmatic series, the igneous units ...
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The Niaz copper prospect is located in west of Meshginshahr, east of Gharehdagh mineralization zone. The lithologic units in this area include intermediate igneous sub-volcanic (granodiorite, quartz monzonite, quartz monzo-diorite) and pyroclastic rocks. In terms of magmatic series, the igneous units in this area have high-K calc-alkaline to shoshonitic characteristics. Tectonically, the igneous units in this area lie in collision (subduction) particularly post-collision zone. Based upon mineralogy and paragenetic sequence, at least five types of veinlets (A, B, C, D, and E) are recognizable in surface and subsurface rock samples at Niaz. The hypogene alterations at Niaz include potassic, propylitic, phyllic, and argillic types. The hypogene mineralization occurred as dissemination, veinlet, stockwork, and brecciation. The hypogene opaque mineral assemblage includes chalcopyrite, pyrite, molybdenite, and lesser amounts of galena, sphalerite, bornite, and magnetite which formed during at least three stages. The principal supergene mineral assemblage includes iron oxy-hydroxides, malachite, azurite, and tenorite in the oxidized zone and covellite and chalcocite in the reduced zone. Studies on fluid inclusions (FI) within the quartz crystals showed that there are four types of FI in room temperature, (1) mono-phase vapor, (2) liquid-rich 2-phase, (3) vapor-rich 2-phase, and (4) multi-phase solid containing daughter solid phases (chiefly halite and hematite) in the Niaz area. The homogenization temperatures (Th) of the studied multi-phase solid and 2-phase FI have 240-540°C and 170-530°C range, respectively. The Th range of FI in the potassic, propylitic, and argillic alteration zones are 180-500°C, 180-560°C, and 170-330°C, respectively.
Original Article
Geomorphology
Hamid Reza Moradi; Vali Rezaei; Mahdi Erfanian
Abstract
Characteristic features of Badland are the lack of vegetation, steep slopes and dense drainage network are considered as important sources of erosion and sediment production in the world. The extent to which different physical and chemical factors of the soil in the formation and spread of pustular erosion ...
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Characteristic features of Badland are the lack of vegetation, steep slopes and dense drainage network are considered as important sources of erosion and sediment production in the world. The extent to which different physical and chemical factors of the soil in the formation and spread of pustular erosion varies from point to point. The aim of this study was to identify the most important factors of physical and chemical properties of soil and environmental factors and soil depth in the spread of Badland erosion in the Zanuzchay watershed of East Azerbaijan province. In this study, factors such as the percentage of sand, silt and clay, PH, EC, SAR, organic matter, gypsum and soil lime in different altitude classes and in the east-west direction and in three depths of 5-0, 30-5 and -60 30 Badland erosion facies were examined. The results of mean comparison using non-paired t-test and Levin test show a significant difference between the variables of pH, SAR, gypsum, clay percentage, silt percentage and organic matter of Badland lands and control lands at the level of one percent. Comparison of average sand in different classes and directions and in depths (0-5) and (5-30) and less than 30 cm in Badland and control areas with Duncan test shows the difference in level five Is a percentage. The results also showed that the average percentage of clay and sand at different heights have a significant difference at the level of five percent.
Original Article
Geography
خداکرم ملایی; لطفعلی کوزه گر کالجی; محمد تقی رضویان; جمیله توکلی نیا
Abstract
In the last three decades, the use of institutional capacity in achieving sustainable regional development has been at the top of the world's development plans, however, in less developed countries such as Iran, this important issue has been neglected. These institutions as development agents have an ...
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In the last three decades, the use of institutional capacity in achieving sustainable regional development has been at the top of the world's development plans, however, in less developed countries such as Iran, this important issue has been neglected. These institutions as development agents have an irreplaceable role in spatial developments. In this study, Bojnourd and Raz and Jorglan counties have been studied to first evaluate the capacity of institutions in charge of development and then analyze the relationship between these capacities on sustainable regional development. The statistical population of the research is at the level of institutional staff and society, in each of which 400 samples have been selected non-randomly to use a descriptive-analytical method; Research findings should be presented. results of the study based on an independent single-sample t-test show that from the perspective of institutional staff, in Bojnourd city the average of institutional capacity components is equal to 2.63 and in Raz and Jorgalan city is 2.44 which is -0.37 and 0.56 is less. According to the opinions of civil society, institutional measures for sustainable regional development in Bojnourd city is 2.44 and in Raz and Jorglan is 2.37, which with 95% confidence level can confirm the significance and differences obtained and understand the poor performance of institutions, the results of Pearson test indicate a positive and significant relationship between some components of the research. Finally, executive proposals such as "setting material and spiritual incentives for institutions to compete for better services and better performance" are presented.
Original Article
Geography
Sohrab Moazzen
Abstract
This research seeks to determine, compare and identify alternative energy scenarios for the study area, focusing on reducing greenhouse gas emissions and reducing dependence on fossil fuels. The present study argues that urban regenerative sustainable energy modeling is a suitable method for quantitative ...
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This research seeks to determine, compare and identify alternative energy scenarios for the study area, focusing on reducing greenhouse gas emissions and reducing dependence on fossil fuels. The present study argues that urban regenerative sustainable energy modeling is a suitable method for quantitative evaluation of current and future urban energy systems in terms of increasing use of renewable energy resources. The research method in the present study is a quantitative and analytical method. Using Area Solar Radiation model, solar energy analysis and modeling was developed for the metropolis of Tehran. Also, wind energy analysis and modeling was performed using Windographer software and Weibull distribution function and finally, biomass energy modeling (municipal waste) for the metropolis of Tehran was done using GIS. The results showed that by using spatial and characteristic data and forming a database, the desired modeling in relation to renewable energies was performed within the framework of the regenerative cities approach.
Original Article
Geology
Hadi Mohammadian; vartan simmonds; Kamal Siahcheshm
Abstract
Samanloo area is located 19 km southwest of Meshginshahr and west of Sabalan Mountain. The lithologic units in this area include Eocene volcano-sedimentary sequence (andesite, trachy andesite with tuff and shale interlayers and mafic lava flows), Oligocene intrusions (granodiorite, granite and monzonite) ...
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Samanloo area is located 19 km southwest of Meshginshahr and west of Sabalan Mountain. The lithologic units in this area include Eocene volcano-sedimentary sequence (andesite, trachy andesite with tuff and shale interlayers and mafic lava flows), Oligocene intrusions (granodiorite, granite and monzonite) and Quaternary units (Andesite – basalt). In terms of magmatic series, the igneous units in this area have high-K calc-alkaline characteristics and formed in magmatic arc tectonic zone. Remote sensing and field studies show that propylitic, argillic, alunite- Pyrophyllite and sericite alterations have occurred in this area. On the basis of statistical correlations elements categorized into three groups: (1) Cu-Ag, (2) As-Sb-S-Au and (3) Pb-Zn-Fe. The maximum anomalies in this region are copper (67800 ppm), silver (18 ppm) and gold (1098 ppm). Opaque mineral assemblage includes pyrite, chalcopyrite, borneite, malachite, azurite, chalcocite, pure copper and to a lesser amounts of covolite. Based on the basic characteristics of Samanloo deposit including the host rocks, texture and structure, mineralogy and alteration, it can be said that the search for the ore-bearing unit (megaporphite andesite units) can lead to the discovery of new copper deposits of Manto-type Cu deposit in the west of Sabalan mountain.
Original Article
Geology
Ashraf Torkian; leyla Shams
Abstract
The studied area is located in theNE-Sonqor city (Sinavand Mountain) in the Sanandaj-Sirjan zone. The aim of this paper is investigation of field relationships, petrographic properties and mineral chemistry of host rock (granite and granodiorite) and mafic microgranular enclaves (MMEs) which sometimes ...
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The studied area is located in theNE-Sonqor city (Sinavand Mountain) in the Sanandaj-Sirjan zone. The aim of this paper is investigation of field relationships, petrographic properties and mineral chemistry of host rock (granite and granodiorite) and mafic microgranular enclaves (MMEs) which sometimes led to evidence of magmatic mixing process. The enclaves are dioritic in composition and mainly have plagioclase, amphibole, small amount of K-feldspar and quartz with predominant microgranular texture. MMEs are elliptical to angular in shape and have a chilled margin at contact with their host rock. According to the results of electron microprop of minerals, the granodioritic host rock and dioritic enclaves have calcic amphiboles type and belong to the subset of magnesium hornblende but host granitic rock are hastingsite in composition. In granodioritic host rocks and enclaves have plagioclase of normal and oscillated zoning texture and they range from oligoclase to andesine. Macroscopic and microscopic features of MMEs such as contact surfaces, different shapes (morphology) of the enclaves, the presence of elongated and euhedral-shape plagioclase crystals, needle apatites, and finally microgranular and poikilitic textures, indicate that MMEs may be the result of rapid cooling and a magma mixing/ mingling of felsic and mafic magmas in the studied area. Based on the amount of Al in amphibole, the pressures in the dioritic enclaves are 2.46 kbar and for their hosts 2.77 kbar. Also, using a thermometer, the average temperature of 711 °C and 750 °C are determined for amphibole-plagioclase to replacing of granitoid and diorite magmas.
Original Article
Geology
Mehdi Yousefi; Seyed Morteza Moussavi; Abolghasem Jafari
Abstract
In the South Dezful Embayment, due to the sequence of the Zagros deformation phases and the tectonic inversion occurrence in the Rag Sefid thrust fault, as well as the reactivation of the Hendijan-Izeh fault, there has been a prependicular interaction in these faults that caused an important effect on ...
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In the South Dezful Embayment, due to the sequence of the Zagros deformation phases and the tectonic inversion occurrence in the Rag Sefid thrust fault, as well as the reactivation of the Hendijan-Izeh fault, there has been a prependicular interaction in these faults that caused an important effect on the structural pattern of folding in the Rag Sefid and Tango anticlines. Regarding the length more than 3 times of the Rag Sefid fault respect to the southern part of the Hendijan-Izeh strike-slip fault, the mean slope of 47 degrees of the Rag Sefid fault relative to the Hendijan-Izeh fault of 80 degrees and according to the general compression direction of N22E in the Southwest of Iran and the southern part of the Henijan-Izeh fault trend (N20E), as well as the Rag Sefid fault trend, which is approximately perpendicular to the general compression direction, the deformation amount of the Rag Sefid fault is more than the Hendijan fault. In this condition, the stress field of the Rag Sefid thrust fault is dominated and due to the less resistance of the rising, folding with a larger amplitude occurs on the the Rag Sefid anticline; so that the folding amplitude in the Rag Sefid anticline is more than twice as large as the Tango anticline, and the tip of the Tango anticline is about 1,200 meters lower than the Rag Sefid anticline.
Original Article
Geology
Behzad Zamani G
Abstract
Due to the importance of pollution and adverse consequences on ecosystems and human life, in this study, in the area of Zailik mine in NW Iran, in order to determine the range of changes in Geoelectrical resistivity of faults with crushed zone containing fluid potential in the study area and separation ...
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Due to the importance of pollution and adverse consequences on ecosystems and human life, in this study, in the area of Zailik mine in NW Iran, in order to determine the range of changes in Geoelectrical resistivity of faults with crushed zone containing fluid potential in the study area and separation of subsurface layers based on their electrical resistance, sounding Electrical transmitters with a maximum length 500 meters has been designed and run.The results of analysis and modeling of 24 soundings have shown that in three faults there is permeability potential or typical faults with crushed zones with fluid and in the rest of the faults the fluid passage potential is not specified.Also, the permeability changes calculated with the geoelectric obtained from geophysical experiments, depots in contour map, have shown that the dominance with permeabilities less than 4 and in fact the impermeability of the foundation stone is the location of the depots. Therefore, it is expected that the infiltration of surface water and possible contaminants from the surface into the seams and crevices as well as spring water will be zero.In fact, the high geoelectric resistance of these rocks indicates their impermeability, which indicates a suitable floor stone from an environmental point of view and reduces the possibility of contamination escaping through seams and fractures to zero. Similarly, in zones 1 to 3 of the mining, a major fault that indicates the permeability and the probability of passage and transmissibility of the fault is not detectable.
Original Article
Geology
Saeed Shabrang; Ehsan Dehyadegari; Mohammad Hoseyn Adabi
Abstract
In order to study the microfacies, sedimentary environment, original mineralogical composition and diagenetic environment of the Garau Formation with the age of Aptian-Albian (Lower Cretaceous), in the high Zagros zone, Aligudarz section in Ghali-Kooh (Lorestan South East) was selected and studied. The ...
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In order to study the microfacies, sedimentary environment, original mineralogical composition and diagenetic environment of the Garau Formation with the age of Aptian-Albian (Lower Cretaceous), in the high Zagros zone, Aligudarz section in Ghali-Kooh (Lorestan South East) was selected and studied. The Garau Formation with a thickness of 483 meters was identified so that the thin sections were prepared and studied from 235 samples of this surface section. Lithology consists mainly of limestone, shale and shaly limestone. The lower boundary of the Garau Formation with brrecia limestones is equivalent to the Gotnia Formation in the form of unconformity and the upper boundary is not clear due to its location in the syncline core. Based on the sedimentary textures, petrographic studies and present fauna, 7 different microfacies have been identified. These microfacies are formed in a deep-sea facies belt belonging to a ramp-type carbonate platform. Petrographic evidence and changes in major and minor elements and comparisons with the ranges presented by various researchers for calcite and aragonite mineralogy show that the Sr/Na ratio, the changes of Sr, Na and Sr/Mn versus Mn suggest original aragonite mineralogy for the Garau Formation. The plot of Sr/Ca versus Mn showed that the Garau Formation is affected by meteoric diagenesis in a closed to open diagenetic system with high and low water/ rock interaction, respectively. By plotting Fe versus Mn, a relative increasing trend between iron and manganese were calculated. This phenomena could be due to anoxic conditions or the effect of meteoric diagenesis.
Original Article
Geology
Alireza Zarasvandi; Bahram Alizadeh; Abbas Maraveneh; Mohammad Hossein Heidarifard
Abstract
Fluid inclusions provide valuable evidence of the formation temperature of minerals, the pressure on their formation environment, the fluids densities that make up the minerals, and the chemical composition of the mineralizing fluids. This data can be used to interpret temperature history, maturity, ...
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Fluid inclusions provide valuable evidence of the formation temperature of minerals, the pressure on their formation environment, the fluids densities that make up the minerals, and the chemical composition of the mineralizing fluids. This data can be used to interpret temperature history, maturity, determination of diagenetic environment, cementation timing, and hydrocarbon migration related to burial history. In this study, in order to determine the physicochemical properties and the API of Asmari reservoir of Ahvaz oil field we have used core samples of 7 wells from this reservoir. These samples were subjected to microscopic, microthermometery, API determination, and Raman spectroscopy studies. The results of this study showed that based on petrographic studies, the variety of inclusions (primary, secondary, and pseudo-secondary), as well as different compounds obtained determined by Raman spectroscopy indicates the activity of different phases of charge of the Asmari reservoir. Based on microscopic studies as wel as, we also calculated the physicochemical properties (last ice melting temperature, homogenization temperature, and salinity) of the reservoir, . Based on this data, two temperature ranges show that it can be concluded that this reservoir had two different charging periods during two charging stages. Also, based on the combination of phases in the inclusions (two-phase, three-phase with oil, etc.) the charging path of the tank can be predicted.
Original Article
Geology
Maryam Teymouri; Ali Kadkhodaei; Nasir Amel; Rahim Kadkhodaei; Gholamreza Zarrini; Soghra Hatamzadeh
Abstract
Mud Volcano systems are the result of a series of reactions from several processes developed from depth to surface. They are one of strangest and most fascinating geomorphologic phenomena. Since the mud volcanoes originate from deeper depths of the earth, they can indicate subsurface processes. They ...
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Mud Volcano systems are the result of a series of reactions from several processes developed from depth to surface. They are one of strangest and most fascinating geomorphologic phenomena. Since the mud volcanoes originate from deeper depths of the earth, they can indicate subsurface processes. They have a relative correlation with oil and gas resources such that they are known as hydrocarbon reserves indicators. Accordingly, they are evaluated to identify oil and gas fields. One of the recent methods of hydrocarbon exploration is geomicrobial exploration that is based on surface excavation technique to identify leaking gases relevant to hydrocarbon microseepage. Th Seyvan mud volcano is located in Seyvan village, a district of the Marand city, the northwest of East Azerbaijan province. In this study, an extensive geomicrobial survey was performed on the Seyvan mud volcanoes samples in order to study abundance of bacterial communities of Methanotrophs, Ethanotrophs and Propanotrophs bacterias. This was further used for primary assessment of the hydrocarbon potential in the study area using counting method on culture plates. A total of 7 soil and mud samples together with two water samples were collected from the study area and transferred to a microbiological laboratory for microbial culture on the samples. Afterwards, the number of microorganisms per gram of soil was calculated. The survey of geomicrobial result showed that in four samples collected from three points of the Seyvan mud volcano, Methanotroph and Ethanotroph anomalies are abundant, while to confirm the presence of propanotroph bacteria, supplementary experiments are needed.
Original Article
Geology
bijan Beiranvand; Nasrin Beiranvand; Hadi Kermanshahi
Abstract
In this research, in order to investigate the geochemical characteristics of oil samples collected from Asmari and Sarvak reservoirs in one of the oil fields in the northwest of the Persian Gulf, methods and techniques of SARA test, gas chromatography, gas chromatography-mass spectrometer and carbon ...
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In this research, in order to investigate the geochemical characteristics of oil samples collected from Asmari and Sarvak reservoirs in one of the oil fields in the northwest of the Persian Gulf, methods and techniques of SARA test, gas chromatography, gas chromatography-mass spectrometer and carbon isotope analysis were used. Based on the results, it seems that the studied oil samples are the same in terms of chemical composition, and except for a small difference in the aromatic, resin and asphaltene fractions, no significant difference is observed in the hydrocarbon fractions of these oils. Also, in order to investigate the sedimentation environment conditions of the source rock producing these oils, the ratios of Pr/ Ph and Pr/ Ph versus CV or standard variable and the curve of changes in Pr/nC17 parameter against Ph/nC18 have been used. The results indicate that all the oil in two reservoirs was produced from the same source rock with an open sea facies and probably deltaic environment. In addition, the investigation of the maturity indices of the aromatic, hopane and aromatic biomarkers related to the oil samples of both formations showed the same characteristic and indicates a degree of maturity in the early to middle of the oil generation window. Accurate biomarker studies indicate the Jurassic age and older for the studied oil producing rocks. Therefore, it can be said that the accumulated oils in the Asmari (Ghar) and Sarvak reservoirs of this field originated from the same formation with the same sedimentation conditions.
Original Article
Geology
Susan Ebrahimi; Moin Alddin Yassari
Abstract
AbstractThe Syahoo salt dome is in the north of Bandar-Abbas in Hormozgan province and structurally it is located in the geological zone of the Zagros. Hormoz Island and the east of the Zagros Mountains, which are related to the geological formations of Hormoz series, consist of many salt diapirs and ...
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AbstractThe Syahoo salt dome is in the north of Bandar-Abbas in Hormozgan province and structurally it is located in the geological zone of the Zagros. Hormoz Island and the east of the Zagros Mountains, which are related to the geological formations of Hormoz series, consist of many salt diapirs and are important in terms of salt and potash deposits. The stratigraphic units of the region include Hormuz series, Asmari, Razak and Mishan Formations, Pleistocene conglomerate and Quaternary sediments. In order to identify rock units and areas containing salt and iron oxide, ASTER satellite images and methods of false band composition (RGB), spectral angle mapper (SAM) and principal component analysis (PCA) were used. The results of these studies show that all three methods have worked well in highlighting iron oxide areas and areas containing salt and show a good agreement with the geological map. Meanwhile, the spectral angle mapper method has better and higher accuracy. The results of remote sensing studies show that the west and east areas of Syahoo salt dome contain a higher potential of potash mineralization. On the basis of these studies, geochemical sampling was done and more than 400 samples were chemically analyzed by XRF method. Also, in order to determine the type of potassium mineral, 17 samples were chemically analyzed by XRD method, the results show that potassium mineral was as sylvite.
Original Article
Geography
Koohzad Raispour
Abstract
Part of the sun's rays are made up of ultraviolet (UV-B) rays, which have short wavelengths and high energy and cause a variety of side effects, including sunburn, skin allergies and skin cancer. The purpose of this study is to estimate the spatiotemporal of solar ultraviolet (UV-B) radiation using the ...
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Part of the sun's rays are made up of ultraviolet (UV-B) rays, which have short wavelengths and high energy and cause a variety of side effects, including sunburn, skin allergies and skin cancer. The purpose of this study is to estimate the spatiotemporal of solar ultraviolet (UV-B) radiation using the aura ozone-monitoring tool in Iran. For this purpose, from the daily calibrated product of level 3 (OMUVBd-L3), the solar ultraviolet (UV-B) index of OMI sensor with spatial resolution of 0.25 × 0.25 arc degrees for the time series 2005 to 2020 used. The data used, after processing and applying the necessary algorithms, were converted into network data and information tables, and the required outputs were prepared on a long-term, seasonal and monthly scale. The results showed that the amount of ultraviolet (UV-B) radiation entering the earth's surface in the warm period of the year and low geographical offerings were higher and the risk of injury Increases the plasticity of these rays in these areas. In contrast, the areas located in the north of the 36 ° orbit receive less ultraviolet radiation. In terms of seasonal average, the highest / lowest UV-B radiation index was related to the summer / winter seasons. Among the studied months, June, July and August had the highest and January, December and November had the lowest UV-B radiation. In addition, although the amount of UV-B radiation has fluctuated during the time series, but in general, no noticeable changes in its process have been observed.
Original Article
Geography
MAJID KIA; mohsen dadras; ZEINAB ALIYAS
Abstract
Aerial photographs were used in the years 1346, 1369, 1374, 1386 and 1396 (51 years) to monitor changes in coastal land use. Coastal uses were manually extracted in ArcGIS software. The results showed that barren lands, rocky hills and scattered forests are the dominant patterns of Qeshm coastal land ...
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Aerial photographs were used in the years 1346, 1369, 1374, 1386 and 1396 (51 years) to monitor changes in coastal land use. Coastal uses were manually extracted in ArcGIS software. The results showed that barren lands, rocky hills and scattered forests are the dominant patterns of Qeshm coastal land use with a relative frequency of 29.3, 23.7 and 10.3%, respectively. In the years 1346 to 1396, barren lands, agriculture, rocky hills, mangrove forest and coastal rocks have decreased by 4851, 297, 7099, 219 and 2938 hectares respectively; However, human settlements, Tepe Mahor, clay beaches, sandy beaches, wharf-ports and industrial areas have increased by 2094, 3813, 136, 5351, 644 and 1249 hectares, respectively. In the years between 1346 and 1396, the highest increase in the use of human constructions was from 1386 to 1396. In the eastern areas, especially the Darghan-Qeshm axis, the most coastal land use changes related to human constructions include the construction of Tula industrial town, the development of Qeshm and Darghan urban settlements, the construction of Bahman and Zakari wharves, the development of Darghan city and Laft wharf. and the area of the coastal city of Qeshm on the east coast increased from 450 hectares in 1386 to 730 hectares in 1396, and the growth of the city has been towards the south and southwest. In the northwestern and southwestern coasts of Qeshm Island, the changes are mainly related to the reduction of forest cover and agriculture.
Original Article
Geography
shahram lotfi gharanchai; Alireza Shakoba; Tayebeh Akbari Azirani; Amemeh Dasht Bozorgi; Fatemeh Rabbani
Abstract
In this study, the climatology of cut-off lows systems at the level of 500 hPa of the northern hemisphere effective on heavy rainfall in Iran has been discussed. The ECMWF reanalysis data were used to identify and track cut-off lows that lasted for more than 48 hours in the statistical period of 33 years ...
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In this study, the climatology of cut-off lows systems at the level of 500 hPa of the northern hemisphere effective on heavy rainfall in Iran has been discussed. The ECMWF reanalysis data were used to identify and track cut-off lows that lasted for more than 48 hours in the statistical period of 33 years (1986-2018). For this purpose, geopotential data, orbital wind data, and temperature data at the level of 500 hPa also were used. Identification of cut-off lows systems was performed using the Tibaldi-Multeni algorithm with auto-detection capability. Based on the results, 632 cut-off lows with a lifespan of more than 2 days were identified during the statistical period. The highest frequency of occurrence of this phenomenon was determined during a year (28 events) and the lowest frequency with (10 events). The highest incidence of cut-off lows was in March, January, and October and the lowest incidence was in July. In terms of seasonality, the highest frequency of events was in winter, and spring and the lowest frequency was in summer. The highest percentage of the impact of cut-off lows on heavy rainfall was in the northwest and northeast and the lowest percentage of the impact of cut-off lows on heavy rainfall was in the southeast region of Iran. In total, the share of cut-off lows in heavy rainfall of Iranian study stations was 8.02%, and the northwest region with 8.13% compared to the total amount of heavy rainfall in Iran.
Original Article
Geology
Behzad Saeedi Razavi; narges monjezi
Abstract
In order to study the biostratigraphy, and depositional environment of Gadvan and Dariyan formations in wells A and B, Gachsaran oil fields, a large number of microscopic thin sections have been studied. This oil field is located 220 km southeast of Ahvaz city. In this study, the Gadvan formation consists ...
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In order to study the biostratigraphy, and depositional environment of Gadvan and Dariyan formations in wells A and B, Gachsaran oil fields, a large number of microscopic thin sections have been studied. This oil field is located 220 km southeast of Ahvaz city. In this study, the Gadvan formation consists of three sections: lower shale, khalij limestone, and upper shale, and in both studied sections, the Kazhdami formation is disconformity placed on the Dariyan formation. The border between Gadvan and Dariyan formations is disconformity. In the studied field, the following biological zones were identified for Gadvan and Dariyan Formations, which include the following:1) Choffatella decipiens - Pseudocyclammina littus -Trocholina elogatus Assemblage Zone, 2) Mesorbitolina texana - Choffatella decipiens Assemblage Zone. Based on biostratigraphy data, the age of the former Aptian Gadvan and late Dariyan Aptian Formations was considered. Microfacies study of the Dariyan and Gadvan led to recognition of 6 microfacies in 3 facies belt inclusive, Inner ramp, Mid-ramp, Outer ramp. Microfacies interpretation which is done based on the fauna mainly indicates ramp environment. Also uniform variation of microfacies and absence of rim and buildup faunas predicted as hemoclinical carbonate ramp.
Original Article
Geology
Nikoo Shiroud Issa; Alireza Ganji; ali moghimi kandelous; Saeid Hakimi Asiabar
Abstract
Cheshmeh Kileh catchment has two main tributaries, Dohezar and Sehezar, which, after surveying mountainous areas, join in a plain area. The center of gravity was determined using a Digital Elevation Model (DEM). Sampling points were determined based on the degree of waterway and possible terrestrial ...
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Cheshmeh Kileh catchment has two main tributaries, Dohezar and Sehezar, which, after surveying mountainous areas, join in a plain area. The center of gravity was determined using a Digital Elevation Model (DEM). Sampling points were determined based on the degree of waterway and possible terrestrial and anthropogenic pollutants. After sampling, the samples were sent to the laboratory to determine the concentration of the main anions and cations, Acidity, TDS, Conductivity and Alkalinity. To study the hydrogeochemical changes in the catchment area, Piper, Durov, Stiff, Schoeller and radial Plot diagrams were drawn in AqQA software and Gibbs diagram and role index diagram were drawn in Excel. Then the process of hydrochemical evolution, type and hydrochemical facies of water were determined and the hydrogeochemical control mechanism was investigated. According to Piper diagram, sample CH1 has sulfate-calcium type and other samples in Sehezar river and also Dohezar river have bicarbonate-calcium type. According to the Gibbs diagram, the main factor controlling water chemistry in the Cheshmeh Kileh catchment is the chemical weathering of the minerals that make up the rocks, and only in the CH16 sample (landfill) was the anthropogenic factor effective. Using Stiff diagram patterns, the origin of water in CH1 sample was determined from gypsum lithology, and other samples were mostly from limestone lithology. In general, it can be concluded that the chemical composition of water in Cheshmeh Kileh catchment has been affected by dissolution and oxidation of calcites and sulfides, as well as oxidation and weathering of silicates and sulfides.
Original Article
Geology
Ali Lotfi Bakhsh
Abstract
Geochemical and isotopic characteristics of freshwater or continental carbonates are different from each other. The study of carbon and oxygen stable isotopes is one of the most useful study tools for carbonates, including travertine deposits. In Borjlu range, which is located on the tectonic belt of ...
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Geochemical and isotopic characteristics of freshwater or continental carbonates are different from each other. The study of carbon and oxygen stable isotopes is one of the most useful study tools for carbonates, including travertine deposits. In Borjlu range, which is located on the tectonic belt of Western Alborz-Azerbaijan, the Quaternary-age travertine deposit is located on Pliocene-age andesitic lavas. Based on mineralogical studies, travertines are generally composed of calcite. The average content of barium and strontium in the collected samples are 40.22 and 536.89 ppm, respectively, and according to these values, Borjlu travertine is placed in the hypogean CATT associated to limestone, evaporite and dolomite. The average values of δ13C and δ18O isotopes in the studied travertine are +1.83‰ and -15.51‰, respectively, which are within the range of thermogene-meteogene origin and indicate the mixing of hydrothermal fluids with meteoric waters. Also, the average value of δ13C(CO2) is -8.3‰ and suggests an inorganic and thermogenic origin for CO2. It is thought that hydrothermal fluids rich in CO2 have provided calcium bicarbonate ions necessary for the formation of travertine after circulating within the limestone unit in the area and reaction with it. Then these fluids ascended through the fault systems and after mixing with meteoric waters, deposited travertine on the surface.
Original Article
Geology
Samin Safaee; Abdolreza Partabian; Ali Asghar Moridi Farimani
Abstract
In this work, the multiple inversion method and a field collection of brittle deformation markers were used to assess the paleo-stress in the Koleh Sangi deformed area to the north of Zahedan. The features of fault surfaces and associated slickenside were gathered for this purpose from different sites. ...
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In this work, the multiple inversion method and a field collection of brittle deformation markers were used to assess the paleo-stress in the Koleh Sangi deformed area to the north of Zahedan. The features of fault surfaces and associated slickenside were gathered for this purpose from different sites. The principal stress values and stress ellipse shape for each location were determined using MIM software and the multiple inversion method. Drawing diagrams and analyzing figures demonstrates the influence of several tectonic phases throughout the region's, including three compressional phase 1. N84°E compressional phase 2. Compressive N59°E phase that youngest rocks impacted. 3. N10 compressive phase, which compatible with Major fault in this region. 4.The The youngest phase reveal a transtension regime. In other words, in the studied area, a compressive phase has worked with the change of the northeast-southwest trend from old to new. This indicates a counter-clockwise rotation from N84 degrees in to N59 and then to N10 degrees , which can be attributed to the convergence of the Arabian plate with Eurasia. The compressive phase was followed by a transtension regime with a northwest-southeast trend, which impacted by the Zahedan fault.
Original Article
Geology
Hamid Rostamipour; Mehrdad Behzadi; mehrdad movahedi; mohammad amini
Abstract
Northern Hired mining area with an area of about 25 square kilometers is located in South Khorasan province and 140 kilometers south of Birjand city. in this area, intermediate to acidic intrusive masses with the composition of granodiorite to granite have penetrated and affected the Tertiary sedimentary-volcanic ...
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Northern Hired mining area with an area of about 25 square kilometers is located in South Khorasan province and 140 kilometers south of Birjand city. in this area, intermediate to acidic intrusive masses with the composition of granodiorite to granite have penetrated and affected the Tertiary sedimentary-volcanic sequence. The most important changes that have been detected on the surface are:1) quartz-tourmaline-sericite, 2) carbonate and 3) propylitic. In observations and field studies with 20 times magnification and also petrographic and mineralogical studies: hematite, limonite, goethite, specularite, pyrite, pyrite oxide, chalcopyrite, bornite, malachite, quartz, malachite, Milky quartz, azurite, tourmaline, cinnabar, stibnite, realgar, orpiment, galena, sphalerite have been observed in different parts of this area. Mineralization in faulted and altered zones is veined. In the analyzed samples from this area, 57 samples have values higher than 100 ppb of gold, of which 17 samples have values higher than 500 ppb of gold and a maximum of 3362 ppb of gold and 24 samples have values between 200 and 500 ppb of gold. By drawing a cluster diagram of the analyzed elements and considering the correlation of aluminum and titanium elements as well as chromium and nickel, it can represent a subduction environment. Also, the correlation of iron and sulfur elements with gold element indicates epithermal mineralization
Original Article
Geology
Reza Ahmadi; Javad Ehsan nejad
Abstract
In Aliabad copper deposit located in Taft city of Yazd province, 1666 magnetic data points as well as resisitivity and induced polarization through rectangular configuration and along four profiles have been surveyed. In the present research, first, 2-D smooth inverse modeling of resistivity and chargeability ...
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In Aliabad copper deposit located in Taft city of Yazd province, 1666 magnetic data points as well as resisitivity and induced polarization through rectangular configuration and along four profiles have been surveyed. In the present research, first, 2-D smooth inverse modeling of resistivity and chargeability data for four profiles was carried out by least squares error method using Res2dinv software. Afterward, the operations of processing, comparison and analysis of magnetis, resistivity and chargeability data from the geophysical profiles was performed and their relationship with mineralization was determined. The results show that in general there is a good accordance between magnetic and geoelectric data and the anomalies in the area are often related to metallic mineralizations. Then, to achieve the spatial structure governing on resistivity and chargeability data of the region, strike variograms were drawn in two horizontal directions of north-south and east-west as well as vertical (depth) direction. The results revealed that all theoric variogram models according to experimental variograms are spherical type and the region has geometric anisotropy. In the next step, based on the results of variography operation, 3-D models of resistivity and chargeability data were produced using Rockworks software through interpolation algorithm of advanced inverse distance weighted. At the end, on the basis of 3-D performed modeling the position of the most promissing and appropriate mineralization area was determined as well as drilling of a vertical exploratory borehole with the length of 80 m was proposed in this location.
Original Article
Geology
Firoozeh HashemiYazdi; Freshteh Sajjadi Hezaveh; Zahra Mohammadi Manesh; Narges Sadat Mirpoor Shah Abolghasemi,
Abstract
In order to reconstruct the paleoclimate of the Nayband Formation (Qadir Member) in the south of Tabas, 62 samples collected from the exploration well no. 948b for palynological investigations. The assemblage of diverse palynomorphs includes spores and pollen of land plants, dinoflagellates cysts, foraminiferal ...
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In order to reconstruct the paleoclimate of the Nayband Formation (Qadir Member) in the south of Tabas, 62 samples collected from the exploration well no. 948b for palynological investigations. The assemblage of diverse palynomorphs includes spores and pollen of land plants, dinoflagellates cysts, foraminiferal test linings, acritarchs and algal spores with moderate to good preservation. The parent plants of existing miospores show that the diversity and abundance of ferns is 64%, cycadophytes 16%, lycophyta 9%, conifers 4%, gynophytes 4%, pteridospermophyta 2% and bryophyta 1%. The maximum diversity and relative abundance belongs to miospores attributed to ferns (20 genera and 64%), which indicates their abundant presence in the composition of vegetation around the sedimentary environment of the studied deposits and indicates the predominance of warm to semi-warm climate with high humidity at that time of deposition.Based on the model of Sporomorph EcoGroups, miospores typifying all the six plant communities are present in the studied strata, but the highest frequency is related to the lowlands SEGs. In order to reconstruct the paleoclimate variation, the large quantity percentage of four main plant groups (Hydrophilic, xerophilic, Thermophilic, Psychrophilic) was calculated and the paleoclimate study was determined by the pattern of relative abundance of drier/wetter and warmer/cooler elements. The consequences of these calculations approve the warm to semi-warm climate with high humidity conditions. Also, the paleogeographic position of Iran during the Late Triassic in the southern active margin of Eurasia (Turan Plate) is another confirmation of this type of climate.
Original Article
Geology
Mohsen Ehteshami-Moinabadi; Shahram Nasiri; Ali Saket; Fatemeh Moradi Ghahdarijani
Abstract
The earthquake risk assessment studies in the Tehran metropolis have been focused mainly on earthquake data and technical aspects of buildings and structures. In the meantime, the data on the fault that can cause earthquakes and the related triggered fracture system, like the potential of direct surface ...
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The earthquake risk assessment studies in the Tehran metropolis have been focused mainly on earthquake data and technical aspects of buildings and structures. In the meantime, the data on the fault that can cause earthquakes and the related triggered fracture system, like the potential of direct surface rupture that can be developed or occur as the result of an earthquake faulting, have not been significantly updated. The land use changes and the growth of the metropolis of Tehran during the last two decades, especially in the city's northern half, with the lack of any regulatory action on the fault zone, are escalating the risk of surface rupture. In this regard, the need to update the fault map and establish a fault zone regulatory act is paramount to importance. This research has first investigated the place of surface rupture studies caused by earthquakes worldwide and the problem of fault boundaries. Then, by reviewing the existing information and combining it with new satellite data, an updated map of the faults in the northern zone of Tehran city has been presented. In this map, along with introducing new trends, the continuation of some faults and especially the dense network of faults related to the northern system of Tehran, have been identified. The result of the overlapping faults with urban structures and building areas shows that in the lack of regulation, the fault zone's ignoring continues in the new constructions of the Tehran metropolis. It is estimated that more than twenty hospitals...
Original Article
Geography
Aboulfazl Heydari; Azar Zarrin; Abbasali Dadashi-Roudbari
Abstract
Today, reanalysis datasets have become an irreplaceable part of climate studies. This research was conducted with the aim of assessing the temperature accuracy of the ERA5 dataset for two deterministic and probabilistic versions (multi-member ensemble). For this purpose, the temperature data of two deterministic ...
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Today, reanalysis datasets have become an irreplaceable part of climate studies. This research was conducted with the aim of assessing the temperature accuracy of the ERA5 dataset for two deterministic and probabilistic versions (multi-member ensemble). For this purpose, the temperature data of two deterministic and probabilistic versions of ERA5 with two horizontal resolutions of 0.25o and 0.5o during the period of 1981-2020 have been used. Then from 10 different members of the probabilistic version of ERA5-EDA, a multi-member ensemble was generated. In order to assess different versions of ERA5, the temperature data of 49 stations were used using KGE, RMSE, Bias, and PBIAS metrics. Comparing the ERA5 dataset with observations, ERA5 shows good performance to estimate temperature over Iran. Although ERA5 can appropriately estimate the temperature in all three versions in the country, the bias and error of the mountainous regions and the southern coast of the Caspian Sea were more than that of the arid and semi-arid interior regions. In general, the deterministic version of ERA5-0.5o has shown a significant underestimation in Iran. This is despite the fact that the probabilistic version with the same horizontal resolution has an overestimation. Among the three examined versions, the deterministic version of ERA5-0.25o has provided the highest performance in estimating Iran's temperature. This version estimates the temperature of the country by 9.36% higher than the observations and its bias in the area-averaged is 1.07oC. All three versions of the ERA5 dataset have estimated the maximum temperature of Iran with high accuracy.
Original Article
Geology
saeideh shakery; ahmad lotf abad arab; mohammad reza vaziri
Abstract
. South Golbaf flysch sediments in Kerman province belong to the Late Cretaceous (Coniacian-Santonian) age with a thickness of the 147 meters and consist of siltstone, silty sandstone and shale. The studied section contains the effects of Ichnospecies and Ichnogenus, that include Planolites isp., Paleophycus ...
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. South Golbaf flysch sediments in Kerman province belong to the Late Cretaceous (Coniacian-Santonian) age with a thickness of the 147 meters and consist of siltstone, silty sandstone and shale. The studied section contains the effects of Ichnospecies and Ichnogenus, that include Planolites isp., Paleophycus isp., Ophiomorpha rudis, Thalassinoides suevicus, Helminthopsis isp., Helminthorhaphe felxcous, Cochlichnus isp., Cosmorhaphe isp., Zoophycos isp. And Paleodictyon strozzii were identified in the detrital layers of this complex. These Trace fossils are mostly creep-nutritional or nutritional effects. These fossils are found in shallow to Turbidite marine environments that are diverse and well preserved, which is most common in the middle part. Therefore, the presence of abundance and diversity Ichnogenus can be an important imdication for the systematic identification and confirmation of the presence of Coniacian-Santonian Turbidite systems in the study area. These sequences can be comparable and Consistens with similar sequences in other parts of Iran and the world.
Original Article
Geology
Amir moham,mad Jamali; Ali Mobasheri; Zohreh Darvish
Abstract
A thick succession of pyroclastic and volcanic rocks interbedded with trigenous, carbonate and evaporate sediments of Eocene age are exposed in southeast of Nizar, Qom. Carbonate deposits of E5 lithozone were investigated in this study. The most important identified diagenetic phenomena was silicification ...
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A thick succession of pyroclastic and volcanic rocks interbedded with trigenous, carbonate and evaporate sediments of Eocene age are exposed in southeast of Nizar, Qom. Carbonate deposits of E5 lithozone were investigated in this study. The most important identified diagenetic phenomena was silicification in these sediments proved by petrography studies on thin sections. In these sediments silice is present as calsedoni, microquartz and megaquartz and silisification mainly observed as replacements and filling of vugs. Conducted studies reveal that skeletal factors play an important role in amount and manner of bioclasts silicification, so that silicification is more common in hyaline foraminifera. No silicification was observed in foraminifera with porcelanous test. Foraminifera with same hyaline test were affected differently by silicification. The most silicification is observed in Assilina and Nummulites genera. This phenomenon did not have any effect or observed rarely in some foraminifera with hyaline test such as Discocyclina, Operculina and Rotalia.
Original Article
Geography
Bromand Salahi; Mahnaz Saber
Abstract
In this research, the effect of climate change on the amount of potential evapotranspiration (ETp) in the southern part of the Aras River basin was estimated and evaluated using the downscaled data of the CanESM2 climate model at the SDSM downscaling model under the RCP scenarios during the period 2021-2050 ...
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In this research, the effect of climate change on the amount of potential evapotranspiration (ETp) in the southern part of the Aras River basin was estimated and evaluated using the downscaled data of the CanESM2 climate model at the SDSM downscaling model under the RCP scenarios during the period 2021-2050 using the Hargreaves-Samani method and compared with the values of the base period (1985-2005). The ETp estimated by this method for the Aras Basin during the future period based on the down-scaled temperature data of the CanESM2 model under RCP scenarios showed that the amount of this variable under the RCP2.6 scenario compared to the base period, slightly decreased and under the RCP4.5 and RCP8.5 will have a slight increase. ETp of this basin according to stations in Ardabil, Ahar and Khoi will have a decreasing change and an increasing change in ParsAbad and Jolfa. The amount of this increase was estimated to be 29 mm at ParsAbad and 12.2 mm at Jolfa. The monthly ETp of the basin in the future period was estimated to increase approximately in January, April to June and August with a range between 0.1 to 24.3 mm maximum compared to the base period, and if the scenarios occur in the future period, this increase means an increase in the water requirement of plants in the future period in during the growing season, a decrease in infiltration and an increase in evaporation of water resulting from rainfall and a decrease in the feeding of aquifers.
Original Article
Geography
Mahmoud Ahmadi; Negar Mohammadimehr
Abstract
One of the effective events of climate change is aerosols. Investigating the effects of climate change on Southwest Asia's aerosols is very important as one of the most important aerosol centers in the world. The aim of this research is to investigate the effects of climate change and predicting in Southwest ...
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One of the effective events of climate change is aerosols. Investigating the effects of climate change on Southwest Asia's aerosols is very important as one of the most important aerosol centers in the world. The aim of this research is to investigate the effects of climate change and predicting in Southwest Asia using the output of the GFDL-ESM4 model from the set of CMIP6 models under the optimistic scenario (SSP1.2.6) during the near future period (2021-2060).The research method was first used for the anomaly of aerosols from a historical period of 40 years (1975-2014). Then, CMIP6 models, GFDL-ESM4 model were used to investigate the trend of air conditioners until the end of this century. Next, the optimistic scenario (SSP1-2.6) was used for the forecasting period of the near future (2021-2060). The results showed that the maximum amount of aerosol is in summer and spring and its minimum is in autumn and winter. In the winter season of the Arabian Peninsula, especially the eastern regions, in the spring season in the east of the Arabian Peninsula, in the summer season in the southeast of the Arabian Peninsula and in the southeast of Iran, and in the autumn season in the northern half of Arabian and in the east of Iran, they have the highest frequency of aerosol. According to the optimistic scenario, summer and spring seasons have the highest amount of aerosol.
Original Article
Geomorphology
hamzeh saeediyan
Abstract
In this study, in order to determine the type of relationship between runoff production and soil chemical properties in different land uses of Gachsaran Formation deposits, a part of Kuhe Gach watershed of the Izeh city with an area of 1202 hectares was selected. In this study, the relationship between ...
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In this study, in order to determine the type of relationship between runoff production and soil chemical properties in different land uses of Gachsaran Formation deposits, a part of Kuhe Gach watershed of the Izeh city with an area of 1202 hectares was selected. In this study, the relationship between runoff and soil chemical properties in different land uses of Gachsaran Formation was determined using univariate regression. Then, sampling of runoff production in 6 points with 3 replicates and in different rainfall intensities of 0.75, 1 and 1.25 mm/minute in three uses of the range, residential area and agricultural lands with the help of the rain simulator was done. In addition, the same number of runoff sampling was performed on soil chemical properties such as organic matter, soil salinity, soil acidity and carbonate calcium. SPSS and EXCEL software were used for statistical analysis. The results showed that in total, in Gachsaran Formation and in range, agricultural and residential land uses and in all three intensities of 0.75, 1 and 1.25 mm/min, soil organic matter in six cases had a negative relationship and in three cases showed positive relationship with runoff production. Soil salinity showed a negative relationship in five cases and a positive relationship in four cases, soil acidity showed a negative relationship in six cases and a positive relationship in three cases, and soil carbonate calcium had a negative relationship in eight cases and in one case showed a positive relationship with runoff production.
Original Article
Geology
Armin Omidpour; Roghayeh Fallah-Bagtash; Hossain Rahimpour-Bonab; Reza Moussavi-Harami; Asadollah Mahbobi
Abstract
In this research, dolomitization models of the Asmari Formation with 363.9 meters thickness were investigated in the Shadegan Oil Field in the Dezful Embayment, Zagros Basin. In the Shadegan Oil Field, the Asmari Formation consists mainly of limestones and porous dolostones associated with sandstones, ...
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In this research, dolomitization models of the Asmari Formation with 363.9 meters thickness were investigated in the Shadegan Oil Field in the Dezful Embayment, Zagros Basin. In the Shadegan Oil Field, the Asmari Formation consists mainly of limestones and porous dolostones associated with sandstones, and shales. In the SG-11 well, The Asmari Formation with Oligocene and lower Miocene in age conformably overlies the marly and shaly Pabdeh Formation and is, in turn, conformably overlain by the evaporites of the Gachsaran Formation. The Oligocene-Miocene Asmari reservoir is dominated by heterogeneity in various aspects, especially porosity and permeability caused mainly by dolomitization. Therefore, dolomitization is one of the important diagenetic processes in the Asmari formation, which has played an important role in controlling the reservoir quality of this formation. This formation has undergone complex diagenetic alteration represented mainly by multiple generations of dolomites. Dolomite types includes (i) very finely-crystalline, fabric-retentive dolomite (D1), (ii) fine to medium-crystalline, fabric-retentive dolomite (D2); (iii) medium to coarse-crystalline, fabric-destructive dolomite (D3); and (iv) very coarsely-crystalline, non-planar saddle dolomite (D4). Petrographic and geochemical evidence, and especially interrelation of facies with dolomite distribution, are consistent with the dolomitization by five different mechanisms/models in the carbonate platform of the Asmari Formation in the Shadgan Oil Field. D1 substituted by micritic matrix in mud-supported facies before early compaction. D2 and D3 were formed by the reflux of warmer and more saline fluids during intermediate burial, and also by the recrystallization of D1.
Original Article
Geomorphology
Hadiseh Seddighi; Ahmad reza Ghasemi
Abstract
Landslides are one of the causes of degradation of sloping lands, especially in non-dense sedimentary layers. In this study, Chaharmahal and Bakhtiari province as an important mountainous region in the country was studied. Nine factors including distance from fault, slope, slope direction, land use, ...
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Landslides are one of the causes of degradation of sloping lands, especially in non-dense sedimentary layers. In this study, Chaharmahal and Bakhtiari province as an important mountainous region in the country was studied. Nine factors including distance from fault, slope, slope direction, land use, precipitation, lithology, elevation classes and distance from river and road as independent variables, were selected. To analyze the data, first 200 landslides and 200 points without landslides were randomly selected. After preparing the layers, the logistic regression model was performed to investigate the role and weight of each of the 9 independent variables. The accuracy of the model results was checked using three statistics, R2 Naglerk, R2 Cox and Snell and factor-2LL. The results showed that, texture and slope of the earth can be considered as the most effective factors in creating landslides in the region. After that, the distance from roads and finally the amount of rainfall has the greatest impact on landslides in the region. The evaluation results of the model obtained from these five parameters, showed that the overall accuracy of the model is 90.9% and acceptable. Finally, based on the obtained results, a landslide risk zoning map was prepared for the study area. The results show that 47% of the area of the province is in the area with low landslide risk, 39.2% is in the area with moderate risk and 13.8% of the study area is in the area with high probability of landslides.
Original Article
Geomorphology
Seyyed Javad Hosseini; Mojtaba Yamani; Abolghasem Gorabi; Shirin Mohammadkhan
Abstract
Neotectonic movements after the establishment of the contemporary stress regime in each region are considered to be new tectonics of that region. Examining the morphology of basins using different indices is one of the methods of estimating the state of neotectonics in different areas. Zanjanrud is ...
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Neotectonic movements after the establishment of the contemporary stress regime in each region are considered to be new tectonics of that region. Examining the morphology of basins using different indices is one of the methods of estimating the state of neotectonics in different areas. Zanjanrud is one of the main basins of Zanjan province, which is of vital importance. The aim of the current research is to investigate and compare the neotectonics of Zanjanrud sub-basins using different indices of the basin shape and therefore geological information, topography, DEM and GIS, WMS and Excel software have been used. The results showed that 8 sub-basins with the highest figures of the shape index are located in the northwest side of the basin which indicates the highest level of involvement of neotectonic compared to other parts. The presence of 5 sub-basins with a basin shape index higher than 4 in the northwest area can also strengthen the hypothesis that the level of neotectonic activity in the western half is higher than the eastern one. These results are consistent with the distribution of active faults in the region. Out of 18 sub-basins with a low tectonic dynamic level, the frequency of sub-basins is higher in the southeastern half of the basin. The analytic results showed that the southeastern side was in the third place in terms of the dynamics and involvement of active tectonics, and the northeastern side has the lowest level of neotectonic activity compared to other parts of the Zanjanrud basin.