Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Statistical simulation of extreme temperatures in Zanjan based on climate scenarios Statistical simulation of extreme temperatures in Zanjan based on climate scenarios 1 19 103377 10.48308/esrj.2023.103377 FA Leila Ahadi Department of Geography, Faculty of Social Sciences, Zanjan University, Zanjan, Iran 0000-0002-2848-1569 Hossein Asakereh Department of Geography, Faculty of Social Sciences, Zanjan University, Zanjan, Iran 0000-0001-7699-0547 Yunes Khosravi Department of Environmental Sciences, Faculty of Science, Zanjan University, Zanjan, Iran Journal Article 2022 07 06 Introduction: Climate is one of the most fundamental factors in the structure of the planet Earth. Climate change can have many feedbacks and consequences. Due to the increase in climatic extremes and natural hazards in Iran, which is characterized by ecological sensitivity, these events have a significant impact on the state of water resources, agriculture, energy, tourism, and bio-climatic conditions; Therefore, studying this field is an inevitable necessity. The main goal of the current research is to investigate the simulation of average values and minimum, maximum and average daily temperatures of Zanjan based on climate scenarios and using the SDSM model. Materials and methods: The method of carrying out descriptive-analytical research and the method of collecting data is library (documents). SDSM model and climate scenarios (RCP2.6, RCP4.5 and RCP8.5) have been used to simulate temperature variables. The data used includes the average, minimum and maximum daily temperature recorded at the Hamdid Zanjan station during the period of 1961-2021 and the data of the general atmospheric circulation model to simulate climate variables in future periods. In order to obtain the most suitable atmospheric variables for estimating triple temperature profiles, the relationship between dependent variables (minimum, average and maximum daily temperature) with independent atmospheric variables (NCEP) was examined to select independent variables and recalibrate the model for dependent variables. Also, the Markov chain model has been used to investigate the probabilities of Frein events. In order to recalibrate the SDSM model, the observational data of Zanjan station and the data of NCEP National Center for Prediction of Environmental Variables were divided into two periods: 1961-1990 and 1991-2005. The first period was used to calibrate the model. Results and discussion: The simulation results of the three studied temperature variables showed that in all scenarios, they will increase the most in the period of 2082-2100 compared to the values of these variables in the base period (1961-2021). The monthly review of the simulated data and the observed data of the studied variables showed that based on the studied scenarios and the SDSM model, it was determined that from 2022-2100 the minimum temperature will increase by 2 degrees, the maximum and average temperature by 3 degrees. The average minimum and average temperature will increase the most in January and February and the least in October. While the average maximum temperature will increase the most in August and the least in April. Conclusion: Result shows that all seasons of the year will become warmer, especially the cold seasons of the year. In other words, the cold seasons will be shorter. The number of extreme frequencies observed in all three temperature parameters for the 25th and 75th quartiles is less than the number of simulated extreme temperature events in all three scenarios. The highest number of extreme low frequencies is expected in January and the highest number of extreme high frequencies is expected in July. Introduction: Climate is one of the most fundamental factors in the structure of the planet Earth. Climate change can have many feedbacks and consequences. Due to the increase in climatic extremes and natural hazards in Iran, which is characterized by ecological sensitivity, these events have a significant impact on the state of water resources, agriculture, energy, tourism, and bio-climatic conditions; Therefore, studying this field is an inevitable necessity. The main goal of the current research is to investigate the simulation of average values and minimum, maximum and average daily temperatures of Zanjan based on climate scenarios and using the SDSM model. Materials and methods: The method of carrying out descriptive-analytical research and the method of collecting data is library (documents). SDSM model and climate scenarios (RCP2.6, RCP4.5 and RCP8.5) have been used to simulate temperature variables. The data used includes the average, minimum and maximum daily temperature recorded at the Hamdid Zanjan station during the period of 1961-2021 and the data of the general atmospheric circulation model to simulate climate variables in future periods. In order to obtain the most suitable atmospheric variables for estimating triple temperature profiles, the relationship between dependent variables (minimum, average and maximum daily temperature) with independent atmospheric variables (NCEP) was examined to select independent variables and recalibrate the model for dependent variables. Also, the Markov chain model has been used to investigate the probabilities of Frein events. In order to recalibrate the SDSM model, the observational data of Zanjan station and the data of NCEP National Center for Prediction of Environmental Variables were divided into two periods: 1961-1990 and 1991-2005. The first period was used to calibrate the model. Results and discussion: The simulation results of the three studied temperature variables showed that in all scenarios, they will increase the most in the period of 2082-2100 compared to the values of these variables in the base period (1961-2021). The monthly review of the simulated data and the observed data of the studied variables showed that based on the studied scenarios and the SDSM model, it was determined that from 2022-2100 the minimum temperature will increase by 2 degrees, the maximum and average temperature by 3 degrees. The average minimum and average temperature will increase the most in January and February and the least in October. While the average maximum temperature will increase the most in August and the least in April. Conclusion: Result shows that all seasons of the year will become warmer, especially the cold seasons of the year. In other words, the cold seasons will be shorter. The number of extreme frequencies observed in all three temperature parameters for the 25th and 75th quartiles is less than the number of simulated extreme temperature events in all three scenarios. The highest number of extreme low frequencies is expected in January and the highest number of extreme high frequencies is expected in July.

https://esrj.sbu.ac.ir/article_103377_763c4588edd1e9224afacb924a1ee160.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Monitoring the spatial changes of the snow cover of Central Alborz using the SVM algorithm and landsat images Monitoring the spatial changes of the snow cover of Central Alborz using the SVM algorithm and landsat images 20 37 103194 10.48308/esrj.2023.103194 FA Hasan Jems Department of Geography, Faculty of Literature and Humanities, Lorestan University, Khorramabad, Iran Daryosh Yarahmadi Department of Geography, Faculty of Literature and Humanities, Lorestan University, Khorramabad, Iran Abuzar Nasiri Department of Geography, Faculty of Literature and Humanities, Firouzabad Institute of Higher Education, Firouzabad, Iran Hamid Mirhashemi Department of Geography, Faculty of Literature and Humanities, Lorestan University, Khorramabad, Iran Journal Article 2023 02 14 Introduction: The snows of the Alborz mountain range play an important role in providing underground and surface water for the settlements around it and the densely populated Caspian Plain. Global warming has caused changes in the atmospheric-climatic parameters of Iran. These changes will cause changes in the dependent variable, which is the snow cover of the high points of the Alborz Mountains. Its consequences can be accelerating the melting of snow, increasing the process of flooding of rivers and the destruction of habitats and settlements downstream. Therefore, the monitoring of Alborz snow area can be used in formulating water management strategies and sustainable development. Materials and methods: In this study, the temporal-spatial variations of the Central Alborz snow cover on a seasonal scale for the years 1985 to 2020 were monitored using Landsat TM, ETM+ and OLI for 1985, 1995, 2005, 2015 and 2020. SVM algorithm was used to extract the snow cover. Results and discussion: The average snow covers for winter, autumn, spring and summer were 1.19, 0.47, 0.14 and 0.004 million hectares, respectively. Snow covers have been declining from 1985 to 2020, reaching 1.98 million hectares in 2020 from 1.68 in 1985 to 1.68 in winter. In the autumn, it increased from 0.84 in 1985 to 0.15 million hectares in 2020. In the winter of 1985, snow started at an altitude of 1,500 meters, but by 2020 it reached 2,500 meters. In the summer, snow was more than 3,900 meters high in 1985, but peaks more than 4,200 meters in 2015 and 2020. The area of snow cover in Central Alborz has a decreasing trend, which has the highest rate in winter. Conclusion: The results of this study showed that the accuracy of the support vector machine algorithm is more than 0.91% in the classification of Landsat images, this method can be used to extract snow patches; in such a way that it separated the shadow snow and cloud from the snow and identified the accumulation of snow in the valleys. Also using images with spatial resolution of 30 meters and applying classification algorithms for snow extraction is better than using NDSI index and MODIS images. On the other hand, the process of snow cover in central Alborz has been such that during 25 years, the area of snow has decreased from about 0.7 million hectares and a large amount of fresh water storage in Alborz has been lost. Introduction: The snows of the Alborz mountain range play an important role in providing underground and surface water for the settlements around it and the densely populated Caspian Plain. Global warming has caused changes in the atmospheric-climatic parameters of Iran. These changes will cause changes in the dependent variable, which is the snow cover of the high points of the Alborz Mountains. Its consequences can be accelerating the melting of snow, increasing the process of flooding of rivers and the destruction of habitats and settlements downstream. Therefore, the monitoring of Alborz snow area can be used in formulating water management strategies and sustainable development. Materials and methods: In this study, the temporal-spatial variations of the Central Alborz snow cover on a seasonal scale for the years 1985 to 2020 were monitored using Landsat TM, ETM+ and OLI for 1985, 1995, 2005, 2015 and 2020. SVM algorithm was used to extract the snow cover. Results and discussion: The average snow covers for winter, autumn, spring and summer were 1.19, 0.47, 0.14 and 0.004 million hectares, respectively. Snow covers have been declining from 1985 to 2020, reaching 1.98 million hectares in 2020 from 1.68 in 1985 to 1.68 in winter. In the autumn, it increased from 0.84 in 1985 to 0.15 million hectares in 2020. In the winter of 1985, snow started at an altitude of 1,500 meters, but by 2020 it reached 2,500 meters. In the summer, snow was more than 3,900 meters high in 1985, but peaks more than 4,200 meters in 2015 and 2020. The area of snow cover in Central Alborz has a decreasing trend, which has the highest rate in winter. Conclusion: The results of this study showed that the accuracy of the support vector machine algorithm is more than 0.91% in the classification of Landsat images, this method can be used to extract snow patches; in such a way that it separated the shadow snow and cloud from the snow and identified the accumulation of snow in the valleys. Also using images with spatial resolution of 30 meters and applying classification algorithms for snow extraction is better than using NDSI index and MODIS images. On the other hand, the process of snow cover in central Alborz has been such that during 25 years, the area of snow has decreased from about 0.7 million hectares and a large amount of fresh water storage in Alborz has been lost.

https://esrj.sbu.ac.ir/article_103194_b85825497b39b02936abe7bddbc0a096.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Investigation of morphological-tectonic structure of Siah-kuh heights in Damghan area using steepness and concavity parameters Investigation of morphological-tectonic structure of Siah-kuh heights in Damghan area using steepness and concavity parameters 38 51 102248 10.48308/esrj.2023.102248 FA Fatemeh Kiaroostami Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran 0000-0002-7978-9256 Mojtaba Yamani Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran 0000-0002-2042-7365 Abolghasem Gorabi Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran 0000-0002-2787-8687 Seyed Mohammad Zamanzadeh Department of Physical Geography, Faculty of Geography, University of Tehran, Tehran, Iran 0000-0002-5705-577x MohammadReza Ghassemi Department of Geology, Research Institute of Earth Sciences, geological survey and mineral exploration of iranTehran, Iran 0000-0002-0641-0073 Journal Article 2022 08 06 Introduction: Identification of active tectonics in an area and its effects on the morphology of landforms is one of the topics that has always been of interest to geomorphologists. Waterways are among the features that flow a wide range of landforms. These features are sensitive to lithological or tectonic changes and react quickly to these changes. Materials and methods: The study area is located in the south of the Eastern Alborz Mountains and is known as the Siah-Kuh Heights. The main purpose of this study is to investigate the morphological and tectonic structure of Siah-Kuh using steepness and concavity parameters based on the anomalies of longitudinal profiles of the rivers based on the uplift and subsidence axes. In order to calculate the rate of steepness and concavity of longitudinal profiles, the stream power low formula is used based on the two main parameters of drainage area and slope of river. This formula is based on a logarithmic plot of the slope and drainage area for which the appropriate regression line is determined. In this regression relation, the slope of the line is the concavity parameter and the intercept is steepness parameters. Results and discussion: The extent of the Siah-Kuh heights among a series of young Quaternary sediments at a distance of 4 km from the main mountain front, the structure of the Siah-Kuh is similar to Foreberg forms. The eastern part of the Siah-Kuh Foreberg appears to have been covered by Neogene and Quaternary sediments. Its remnants have appeared in the form of deep gorges on the surface. One of the rivers flows on the main surface of Foreberg and the other flows in the drained or buried part of Foreberg. Both rivers have several knick points in their flow path, which are taken from the location of faults and lithological differences of the riverbed. The values of the steepness parameter for the main river and the gully is 121.4 for the main river and 119.96 for the gorges. In contrast, the depression parameter rate in both rivers shows very low and even negative values. Since the sharpness parameter is directly related to the tectonic processes; It can be said that the values of this parameter in both rivers indicate the effect of active tectonics at the level of Foreberg. Conclusion: The studies performed on the study area show that the two factors of active tectonics and lithology have a great impact on the morphological structure of Siah-Kuh Foreberg. Also, factors related to sedimentary flows originating from the uplands of the area have been effective in changing these landforms in the form of burial. Also, the results showed that the use of the method based on longitudinal profile anomalies of the river in the form of steepness and concavity parameters has an effective role in identifying erosion and subsidence axes related to tectonic situation of features in relation to their topographic changes. Introduction: Identification of active tectonics in an area and its effects on the morphology of landforms is one of the topics that has always been of interest to geomorphologists. Waterways are among the features that flow a wide range of landforms. These features are sensitive to lithological or tectonic changes and react quickly to these changes. Materials and methods: The study area is located in the south of the Eastern Alborz Mountains and is known as the Siah-Kuh Heights. The main purpose of this study is to investigate the morphological and tectonic structure of Siah-Kuh using steepness and concavity parameters based on the anomalies of longitudinal profiles of the rivers based on the uplift and subsidence axes. In order to calculate the rate of steepness and concavity of longitudinal profiles, the stream power low formula is used based on the two main parameters of drainage area and slope of river. This formula is based on a logarithmic plot of the slope and drainage area for which the appropriate regression line is determined. In this regression relation, the slope of the line is the concavity parameter and the intercept is steepness parameters. Results and discussion: The extent of the Siah-Kuh heights among a series of young Quaternary sediments at a distance of 4 km from the main mountain front, the structure of the Siah-Kuh is similar to Foreberg forms. The eastern part of the Siah-Kuh Foreberg appears to have been covered by Neogene and Quaternary sediments. Its remnants have appeared in the form of deep gorges on the surface. One of the rivers flows on the main surface of Foreberg and the other flows in the drained or buried part of Foreberg. Both rivers have several knick points in their flow path, which are taken from the location of faults and lithological differences of the riverbed. The values of the steepness parameter for the main river and the gully is 121.4 for the main river and 119.96 for the gorges. In contrast, the depression parameter rate in both rivers shows very low and even negative values. Since the sharpness parameter is directly related to the tectonic processes; It can be said that the values of this parameter in both rivers indicate the effect of active tectonics at the level of Foreberg. Conclusion: The studies performed on the study area show that the two factors of active tectonics and lithology have a great impact on the morphological structure of Siah-Kuh Foreberg. Also, factors related to sedimentary flows originating from the uplands of the area have been effective in changing these landforms in the form of burial. Also, the results showed that the use of the method based on longitudinal profile anomalies of the river in the form of steepness and concavity parameters has an effective role in identifying erosion and subsidence axes related to tectonic situation of features in relation to their topographic changes.

https://esrj.sbu.ac.ir/article_102248_ab47b542f580ccee635cdd11ef442a12.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Temporal-spatial distribution and synoptic patterns of storms with horizontal visibility less than 200 meters in western Iran Temporal-spatial distribution and synoptic patterns of storms with horizontal visibility less than 200 meters in western Iran 52 70 103510 10.48308/esrj.2023.103510 FA Zainab Mohammadi Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran Hassan Lashkari Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran 0000-0002-6007-7275 Journal Article 2022 05 04 Introduction: Dust storms with visibility of less than 200 meters are dangerous storms for human life and activity. By knowing the behavioral characteristics and how these storms form and spread over the sources of dust production, it is possible to reduce its many damages. Materials and methods: According to the purpose of the research, to investigate the historical trend of the occurrence of severe storms and the synoptic patterns that cause such storms, a statistical period of 33 years was selected. Based on this statistical basis, 16 synoptic stations were selected as sample stations. The days in which code was reported in at least two observatories with visibility less than 200 meters were selected as a day with a storm. To select synoptic systems, the days when this phenomenon was reported in at least one third of the sample stations were selected as a dust system. In this way, 68 study samples were extracted. Results and discussion: The highest number of dust storms with visibility less than 200 meters occurs in two turbulent seasons in terms of weather, i. e. winter and autumn. In monthly terms, occurred in January (352 cases) and December. In terms of historical trends, from the beginning of the period to 2007, the number of storms has been almost constant. Since 2008, the number of such storms has increased significantly and this process continued until 2012. In terms of spatial distribution, the highest number of storms occurred in the cold period of the year, in the eastern stations of the region, on the contrary, in the warm period of the year, occurred in the western. Two recurring patterns are the main cause of dust storms in the cold period of the year. In the African gyre pattern, the significant northward expansion of this anticyclone ridge and the cold advection of the subpolar latitudes over the western region of Asia creates a severe temperature and pressure gradient in the entire lower and middle layer of the troposphere. In the Sudan low pattern, with the significant expansion of the Sudan low pressure tongue over the western region of Asia and the formation of a deep trough in the middle layers, it causes the instabilities to intensify over the dust sources of Syria and Iraq. Most summer dust storms have followed a general pattern. In these patterns, three low pressure systems, Saudi Arabia, Pakistan and sometimes Lut desert, are the main cause of dust storms in the lower layer (up to the level of 850hpa). Conclusion: The result of this research showed that storms with visibility of less than 200 meters are increasing in the western region of Iran. In terms of spatial distribution, the highest number of such storms occurs in the cold period of the year in the eastern part of the region. From a synoptic point of view, dust particles rise from dust sources in Syria and western Iraq and enter the eastern part of the study area along the atmospheric currents of the middle layer of the troposphere. Meanwhile, the western part of the study area is affected by the highest number of dust storms in the hot period of the year. Introduction: Dust storms with visibility of less than 200 meters are dangerous storms for human life and activity. By knowing the behavioral characteristics and how these storms form and spread over the sources of dust production, it is possible to reduce its many damages. Materials and methods: According to the purpose of the research, to investigate the historical trend of the occurrence of severe storms and the synoptic patterns that cause such storms, a statistical period of 33 years was selected. Based on this statistical basis, 16 synoptic stations were selected as sample stations. The days in which code was reported in at least two observatories with visibility less than 200 meters were selected as a day with a storm. To select synoptic systems, the days when this phenomenon was reported in at least one third of the sample stations were selected as a dust system. In this way, 68 study samples were extracted. Results and discussion: The highest number of dust storms with visibility less than 200 meters occurs in two turbulent seasons in terms of weather, i. e. winter and autumn. In monthly terms, occurred in January (352 cases) and December. In terms of historical trends, from the beginning of the period to 2007, the number of storms has been almost constant. Since 2008, the number of such storms has increased significantly and this process continued until 2012. In terms of spatial distribution, the highest number of storms occurred in the cold period of the year, in the eastern stations of the region, on the contrary, in the warm period of the year, occurred in the western. Two recurring patterns are the main cause of dust storms in the cold period of the year. In the African gyre pattern, the significant northward expansion of this anticyclone ridge and the cold advection of the subpolar latitudes over the western region of Asia creates a severe temperature and pressure gradient in the entire lower and middle layer of the troposphere. In the Sudan low pattern, with the significant expansion of the Sudan low pressure tongue over the western region of Asia and the formation of a deep trough in the middle layers, it causes the instabilities to intensify over the dust sources of Syria and Iraq. Most summer dust storms have followed a general pattern. In these patterns, three low pressure systems, Saudi Arabia, Pakistan and sometimes Lut desert, are the main cause of dust storms in the lower layer (up to the level of 850hpa). Conclusion: The result of this research showed that storms with visibility of less than 200 meters are increasing in the western region of Iran. In terms of spatial distribution, the highest number of such storms occurs in the cold period of the year in the eastern part of the region. From a synoptic point of view, dust particles rise from dust sources in Syria and western Iraq and enter the eastern part of the study area along the atmospheric currents of the middle layer of the troposphere. Meanwhile, the western part of the study area is affected by the highest number of dust storms in the hot period of the year.

https://esrj.sbu.ac.ir/article_103510_bd4a94c23f83d65d76af1996ca53933c.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Mineralogy, geochemistry and conditions of formation of The Abri and Rahbari Copper deposit, N-W of Daroneh Mineralogy, geochemistry and conditions of formation of The Abri and Rahbari Copper deposit, N-W of Daroneh 71 89 100775 10.48308/esrj.2023.100775 FA Afsane Soltani Department of Geology, Faculty of earth Siences, Shahrood University of Technology, Shahrood, Iran 0009-0000-8201-7161 Farajollah Fardoost Department of Geology, Faculty of earth Siences, Shahrood University of Technology, Shahrood, Iran Journal Article 2022 05 04 Introduction: The sulphide deposits of stratabound and stratiform are one of the largest sulphide deposits for copper mineralization. In Iran, Manto type deposits have been reported just in Urumieh -Dokhtar zone, Sanandaj-Sirjan zone and Sabzevar sub-zone. Abari and Rahbari deposits are among the Manto type deposits in the volcanic-intrusive belt, Khaf- Darooneh and the southern part Sabzevar sub-zone. In this research, mineralogy, geochemistry and formation pattern of Abari and Rahbari copper deposit were discussed and investigated. Materials and methods: In this research, 100 thin and polished sections were prepared and studied, and the studies of fluids inclusion were done by preparing and studying 3 double-polished sections from surface samples. In order to identify minerals and complete alteration studies, 6 samples were analyzed by XRD method and for geochemical studies, 22 samples of ore and volcanic-sedimentary rocks were analyzed by XRF and ICP-MS methods in Binalud deposits Laboratory and Iran mineral processing Research Center. Results and discussion: The stages of mineralization and formation processes can be described in three stages: the first stage: initial diagenesis, the second stage: the burial diagenesis stage, and the third stage: the uplift stage (hydrothermal activities). After extensive volcanic activities, during the diagenesis stage, in this stage, seawater sulfate regenerating bacteria were present in the environment, and their activity has caused regeneration conditions in the basin. As a result, the resulting sulfur with the available iron causes the deposition of pyrite in the form of scattered grains and fills the empty spaces in the rock background. From the stage of diagenesis onwards, burial occurs as a result of the deposition of newer sediments on them. the hydrothermal fluid carries the copper released from the conversion of iron hydroxide minerals into iron oxides, as well as the copper released in the network of feldspar minerals in the transformed volcanic units due to the high environment temperature and circulation in the volcanic and pyroclastic units and then turning up in the rock units, it reached the pyroclastic unit with high porosity and permeability, and chalcocite and chalcopyrite minerals were formed in the burial diagenesis stage. upwelling Stage (hydrothermal activities): at the end of the burial process and with the beginning of the uplift of the area and faulting, the open spaces increase by Darooneh and Binalood faults, which ultimately causes the activity and concentration of sulfide and copper oxide mineralization will start again along the faults, cracks, and even the empty spaces of the pyroclastic units. Conclusion: The Eocene volcanic rocks of the magmatic belt in the north of the structural zone of central Iran are the host of Abari and Rahbari copper deposits with the dominant composition of andesite and basaltic andesite. The effective factors copper mineralization in the study areas including: 1) The lithology of host rocks, 2) structural controls, 3) hydrothermal fluids and 4) The presence of intrusive rocks at depth and basaltic dykes. Mineralization is formed in three stages: initial diagenesis, burial diagenesis and uplift stage (hydrothermal activities). So that mineralization in the Abri and Rahbari area is epigenetic, strata bound that is similar to the manto type copper deposits. Introduction: The sulphide deposits of stratabound and stratiform are one of the largest sulphide deposits for copper mineralization. In Iran, Manto type deposits have been reported just in Urumieh -Dokhtar zone, Sanandaj-Sirjan zone and Sabzevar sub-zone. Abari and Rahbari deposits are among the Manto type deposits in the volcanic-intrusive belt, Khaf- Darooneh and the southern part Sabzevar sub-zone. In this research, mineralogy, geochemistry and formation pattern of Abari and Rahbari copper deposit were discussed and investigated. Materials and methods: In this research, 100 thin and polished sections were prepared and studied, and the studies of fluids inclusion were done by preparing and studying 3 double-polished sections from surface samples. In order to identify minerals and complete alteration studies, 6 samples were analyzed by XRD method and for geochemical studies, 22 samples of ore and volcanic-sedimentary rocks were analyzed by XRF and ICP-MS methods in Binalud deposits Laboratory and Iran mineral processing Research Center. Results and discussion: The stages of mineralization and formation processes can be described in three stages: the first stage: initial diagenesis, the second stage: the burial diagenesis stage, and the third stage: the uplift stage (hydrothermal activities). After extensive volcanic activities, during the diagenesis stage, in this stage, seawater sulfate regenerating bacteria were present in the environment, and their activity has caused regeneration conditions in the basin. As a result, the resulting sulfur with the available iron causes the deposition of pyrite in the form of scattered grains and fills the empty spaces in the rock background. From the stage of diagenesis onwards, burial occurs as a result of the deposition of newer sediments on them. the hydrothermal fluid carries the copper released from the conversion of iron hydroxide minerals into iron oxides, as well as the copper released in the network of feldspar minerals in the transformed volcanic units due to the high environment temperature and circulation in the volcanic and pyroclastic units and then turning up in the rock units, it reached the pyroclastic unit with high porosity and permeability, and chalcocite and chalcopyrite minerals were formed in the burial diagenesis stage. upwelling Stage (hydrothermal activities): at the end of the burial process and with the beginning of the uplift of the area and faulting, the open spaces increase by Darooneh and Binalood faults, which ultimately causes the activity and concentration of sulfide and copper oxide mineralization will start again along the faults, cracks, and even the empty spaces of the pyroclastic units. Conclusion: The Eocene volcanic rocks of the magmatic belt in the north of the structural zone of central Iran are the host of Abari and Rahbari copper deposits with the dominant composition of andesite and basaltic andesite. The effective factors copper mineralization in the study areas including: 1) The lithology of host rocks, 2) structural controls, 3) hydrothermal fluids and 4) The presence of intrusive rocks at depth and basaltic dykes. Mineralization is formed in three stages: initial diagenesis, burial diagenesis and uplift stage (hydrothermal activities). So that mineralization in the Abri and Rahbari area is epigenetic, strata bound that is similar to the manto type copper deposits.

https://esrj.sbu.ac.ir/article_100775_83ed4c21673539a06bdb4d218032816e.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Systematic of Upper Cretaceous Flysch deposits ichnofossils in south of Golbaf, Kerman province Systematic of Upper Cretaceous Flysch deposits ichnofossils in south of Golbaf, Kerman province 90 107 103058 10.48308/esrj.2023.103058 FA Saeideh Shakery Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran Ahmad Lotf Abad Arab Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran 0000-0003-0717-1948 Mohammad Reza Vaziri Department of Geology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran Journal Article 2022 05 17 Introduction: The Cretaceous deposits of Golbaf region are part of the Rhine-Guk-Khana Khatun zone in the stratigraphic-structural belt of Rafsanjan (Dimitrijevic and Djokovic, 1973). In this belt, Cretaceous deposits are divided into shallow to deep facies, and the most complete Cretaceous deposits can be found in the Rhine-Guk-Khan Khatun area (Dimitrijevic, 1973). The age of these sediments is Upper Cretaceous (Coniacian-Santonian). These sediments contain clastic deposits that are gradually and with the same slope on the Lower Cretaceous This section has a lithological sequence of columnar silt, silty sandstone, and shale, which contain fossils and species that have been identified in the debris layers of this section. In this article, an attempt was made to systematically identify the existing fossils and discuss and examine their behavioral patterns. Materials and methods: In the field operation, after identifying the intended cut and determining the boundaries as well as the beginning and end of the desired cut, the thickness of each layer was measured and examined. The required information was noted down, and if sampling was done, fossils were taken from the sediments. In the laboratory, after photographing each sample, the characteristics of each fossil, such as shape, size, dimensions and type of preservation in relation to the level of layering, decorations and various components, were identified. Then the trace fossils were classified based on the behavioral status and finally the fossil systematics was written completely. Results and discussion: Trace fossils are biological constructions in sedimentary environments that are formed by organisms in soft to hard sediments. Turbidites are generally found as flysch deposits and are considered as deep basin rock facies. Since the trace fossils in Golbaf region are widespread and abundant, therefore, in order to achieve turbidite sedimentary environments, based on the data of Archeology It is necessary to combine the archeology data with sedimentological data and structural elements. The rock facies of the studied sequence include The facies are siltstone, silty sandstone, and Chile. In these beds, the amount of sedimentation is low to high. According to the archeological data, diversity and abundance of fossils in the studied sedimentary sequence, on the surface of silty sandstone and siltstone layers, it can be concluded that most of the fossils are in the form of molds on their lower surface, in other words, the activity of animals has an effect on They are concentrated on the upper surface and have been molded by silty sandstone and siltstone sediments after deposition. Therefore, most of the fossils were formed in the middle parts after the occurrence of turbulent currents and in a relatively calm environment. Conclusion: Upper Cretaceous flysch deposits in Golbaf area have a good thickness and ichnofossils in this section have a very high diversity and abundance. Ethnological and sedimentology studies on the sediments of the studied area indicate calm conditions in the bed of the basin. According to the type, frequency and spread of fossils in the studied sequence, it can be concluded that a thickness of the Set bar sequence in the south of Golbaf is in suitable conditions for creating fossils. Introduction: The Cretaceous deposits of Golbaf region are part of the Rhine-Guk-Khana Khatun zone in the stratigraphic-structural belt of Rafsanjan (Dimitrijevic and Djokovic, 1973). In this belt, Cretaceous deposits are divided into shallow to deep facies, and the most complete Cretaceous deposits can be found in the Rhine-Guk-Khan Khatun area (Dimitrijevic, 1973). The age of these sediments is Upper Cretaceous (Coniacian-Santonian). These sediments contain clastic deposits that are gradually and with the same slope on the Lower Cretaceous This section has a lithological sequence of columnar silt, silty sandstone, and shale, which contain fossils and species that have been identified in the debris layers of this section. In this article, an attempt was made to systematically identify the existing fossils and discuss and examine their behavioral patterns. Materials and methods: In the field operation, after identifying the intended cut and determining the boundaries as well as the beginning and end of the desired cut, the thickness of each layer was measured and examined. The required information was noted down, and if sampling was done, fossils were taken from the sediments. In the laboratory, after photographing each sample, the characteristics of each fossil, such as shape, size, dimensions and type of preservation in relation to the level of layering, decorations and various components, were identified. Then the trace fossils were classified based on the behavioral status and finally the fossil systematics was written completely. Results and discussion: Trace fossils are biological constructions in sedimentary environments that are formed by organisms in soft to hard sediments. Turbidites are generally found as flysch deposits and are considered as deep basin rock facies. Since the trace fossils in Golbaf region are widespread and abundant, therefore, in order to achieve turbidite sedimentary environments, based on the data of Archeology It is necessary to combine the archeology data with sedimentological data and structural elements. The rock facies of the studied sequence include The facies are siltstone, silty sandstone, and Chile. In these beds, the amount of sedimentation is low to high. According to the archeological data, diversity and abundance of fossils in the studied sedimentary sequence, on the surface of silty sandstone and siltstone layers, it can be concluded that most of the fossils are in the form of molds on their lower surface, in other words, the activity of animals has an effect on They are concentrated on the upper surface and have been molded by silty sandstone and siltstone sediments after deposition. Therefore, most of the fossils were formed in the middle parts after the occurrence of turbulent currents and in a relatively calm environment. Conclusion: Upper Cretaceous flysch deposits in Golbaf area have a good thickness and ichnofossils in this section have a very high diversity and abundance. Ethnological and sedimentology studies on the sediments of the studied area indicate calm conditions in the bed of the basin. According to the type, frequency and spread of fossils in the studied sequence, it can be concluded that a thickness of the Set bar sequence in the south of Golbaf is in suitable conditions for creating fossils.

https://esrj.sbu.ac.ir/article_103058_cc39116c55a051982427605584d45eb8.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Structural evolution of northwest-southeast trend in Hemmatabad area – East Iran Structural evolution of northwest-southeast trend in Hemmatabad area – East Iran 108 122 101386 10.48308/esrj.2023.101386 FA Ebrahim Gholami Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran Mohammadmahdi Khatib Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran Mohsen Karimidehkordi Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran Journal Article 2019 06 20 Introduction: Northwest-southeast structural trend, is one of the dominant structural trends in the east of Iran. Dextral N-S striking Nehbandan fault system, is located between Sistan and Lut structural zones. The tectonic model and growth of northwest-southeast trends in the east of Iran will be introduced by deformation analysis in Hematabad region. Materials and methods: The rock units of the Sistan subzone include: Cretaceous ophiolitic and metamorphic units and flysch-pyroclastic units. Hematabad region includes: ophiolitic units extending in the northwest-southeast direction, volcanic rocks, and sandstone, shale, limestone units with metamorphism ranging from slate, phyllite to schist. The northwest plunging folds in the tertiary’s shale and sandstone units have steep forelimb on the southwest side, which indicates the southwest tectonic vergence. Geometric and kinematic analysis of mentioned fault zones, indicates the main axis of compression in the region has an average trend of N25E. The shear component is dominant in the north-south fault zones and the compressive component is dominant in the northwest-southeast ones. According to the geometrical analysis of the faults and their mechanisms, folds and the rock units outcrop, the activity of the faults in the northeastern part can be considered as older (earlier) faults. Results and Discussion: Based on geomorphological evidences such as displaced rivers, shutter ridges and fault scarps in Hematabad region, fault zones migrate to the southwest. By asessement of the fault and folds, outcrop of the rock units and the morphotectonic features, the following structural model can be presented: The first stage: by NE component of compressive stress, the NW-SE striking Hematabad fault zone in which the pressure component is dominant, ophiolitic units was exposed. The second stage: a new fault the same as Hemmatabad fault zone (NW-SE) has been formed in its southwestern part with a reverse right-lateral mechanism. With the continuation of mentioned deformation, folding of Cretaceous and Paleocene-Eocene sedimentary rocks and displacement in rivers occurred. Third stage: Shutter ridges develop with the formation of new faults. In this model, the growth of the structures has been done from the northeast to the southwest. NE component of compressive stress, has caused folds with a northwest-southeast axial trace in the region. In north-south striking faults, the strike-slip component is dominant, but in northwest-southeast striking faults (such as Hematabad fault zone), the reverse component is dominant. The morphotectonic evidences indicate that the uplift of fault scarps is decreasing from the northeast to the southwest, and the deflection of rivers is decreasing from the southeast to the northwest. Therefore, the tectonic activity in the southeastern part is more than the northwestern part in this region. Conclusion: The growth of structures in this area continues with the creation of NW-SE striking fault zones from the northeast to the southwest, which indicates the structural growth in the northwest-southeast trends in the east of Iran. Introduction: Northwest-southeast structural trend, is one of the dominant structural trends in the east of Iran. Dextral N-S striking Nehbandan fault system, is located between Sistan and Lut structural zones. The tectonic model and growth of northwest-southeast trends in the east of Iran will be introduced by deformation analysis in Hematabad region. Materials and methods: The rock units of the Sistan subzone include: Cretaceous ophiolitic and metamorphic units and flysch-pyroclastic units. Hematabad region includes: ophiolitic units extending in the northwest-southeast direction, volcanic rocks, and sandstone, shale, limestone units with metamorphism ranging from slate, phyllite to schist. The northwest plunging folds in the tertiary’s shale and sandstone units have steep forelimb on the southwest side, which indicates the southwest tectonic vergence. Geometric and kinematic analysis of mentioned fault zones, indicates the main axis of compression in the region has an average trend of N25E. The shear component is dominant in the north-south fault zones and the compressive component is dominant in the northwest-southeast ones. According to the geometrical analysis of the faults and their mechanisms, folds and the rock units outcrop, the activity of the faults in the northeastern part can be considered as older (earlier) faults. Results and Discussion: Based on geomorphological evidences such as displaced rivers, shutter ridges and fault scarps in Hematabad region, fault zones migrate to the southwest. By asessement of the fault and folds, outcrop of the rock units and the morphotectonic features, the following structural model can be presented: The first stage: by NE component of compressive stress, the NW-SE striking Hematabad fault zone in which the pressure component is dominant, ophiolitic units was exposed. The second stage: a new fault the same as Hemmatabad fault zone (NW-SE) has been formed in its southwestern part with a reverse right-lateral mechanism. With the continuation of mentioned deformation, folding of Cretaceous and Paleocene-Eocene sedimentary rocks and displacement in rivers occurred. Third stage: Shutter ridges develop with the formation of new faults. In this model, the growth of the structures has been done from the northeast to the southwest. NE component of compressive stress, has caused folds with a northwest-southeast axial trace in the region. In north-south striking faults, the strike-slip component is dominant, but in northwest-southeast striking faults (such as Hematabad fault zone), the reverse component is dominant. The morphotectonic evidences indicate that the uplift of fault scarps is decreasing from the northeast to the southwest, and the deflection of rivers is decreasing from the southeast to the northwest. Therefore, the tectonic activity in the southeastern part is more than the northwestern part in this region. Conclusion: The growth of structures in this area continues with the creation of NW-SE striking fault zones from the northeast to the southwest, which indicates the structural growth in the northwest-southeast trends in the east of Iran.

https://esrj.sbu.ac.ir/article_101386_ac642275fef3e805efbb309a9848a4db.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Fluid inclusion and stable isotope study of the Baba-Ali and Galali deposits, northwest of Hamedan: Metamorphosed and deformed volcano-sedimentary type of mineralization in northwest of the Sanandaj-Sirjan zone Fluid inclusion and stable isotope study of the Baba-Ali and Galali deposits, northwest of Hamedan: Metamorphosed and deformed volcano-sedimentary type of mineralization in northwest of the Sanandaj-Sirjan zone 123 142 101329 10.48308/esrj.2023.101329 FA Ghodratolah Rostami Paydar Department of Geology, Ahvaz Branch, Islamic Azad University, , Ahvaz, Iran Mansour Adelpour Department of Geology, Faculty of Earth Sciences, Shahid Chamran University of Ahvaz, Ahvaz, Iran 0000-0001-7865-8126 Journal Article 2018 10 20 Introduction: Baba-Ali and Galali deposits are located in 30 and 60 km northwest of Hamedan in northwest part of the Sanandaj-Sirjan zone. The host rocks of these deposits are metavolcano-sedimentary successions of Songhor series in Permo-Triassic age. Stratigraphic position of ore horizons, geometry of orebodies, ore structures and textures in different scales and paragenetic sequence of minerals all show close genetic relation between iron ore and the metavolcanosedimentary and subvolcanic rocks. The host rocks in the area are felsic to intermediate metavolcanic rocks, more than lava and rhyolitic tuffs with interculations of carbonate and metatuff-sandstones. Field observations and petrography show that emplacement of plutons and subvolcanic rock units with composition of gabbrodiorite, quartzmonzodiorite, granodiorite, syenite, syenogranite and granite in these successions caused deformation and metamorphism of ore and country rocks. Materials and methods: In this research, 56 polished sections were prepared from iron ore of Baba Ali and Galali deposits, and the mineralogical characteristics and texture of the mineral in relation to gangue minerals were carefully studied using a reflected light mineralogical microscope. In order to determine the origin of ore-rich fluid, studies of fluid inclusions have been carried out on 6 double polished sections in the research laboratory of Tarbiat Modares University. Also, 29 samples of separated phases of sulphide, oxide-silicate and carbonate minerals from ore and gangue minerals of Baba Ali and Galali iron deposits have been analyzed for stable isotope analysis in Queen's University Isotope Research Laboratory in Canada. Results and discussion: From field evidences, fluid inclusions data, as well as stable isotope analysis in this study, emplacement of plutons and subvolcanic rock units with composition of gabbrodiorite, quartzmonzodiorite, granodiorite, syenite, syenogranite and granite in these successions caused deformation and metamorphism of ore and country rocks. Fluid inclusion studies within the quartz crystals indicate that main salinity varies between 12±5 and 9±5 wt.% NaCl equivalent in Baba-Ali and Galali deposits respectively. Homogenization temperature for Baba-Ali and Galali deposits are 226±5 and 220±5 oC respectively. Occurrence of dynamothermal regional metamorphism in these deposits typically involves a lengthy period of time, during which there was a tendency toward isotopic homogenization specifically in O (3 to 10.5 ‰) and H (-10 to -35 ‰) stable isotopes and show the role of metamorphic waters in mineralization process. Measurement of δ34S (CDT) in first generation of pyrite is higher than another one, so these data confirm the volcano-sedimentary origin of primary iron mineralization. Conclusion: Field observations, structure and texture, host rock, intercualation, geochemistry, alterations, studies of fluid inclusion and stable isotopes in Baba Ali and Galali deposits show that these deposits are volcanic-sedimentary iron deposits. Since most of these mineralizations are located in metamorphosed volcanic-sedimentary units, these rock groups are of great importance in terms of iron exploration. Investigating these stone units in the region and generalizing the evidence obtained from them to similar areas in Sanandaj-Sirjan zone can lead to the identification of this type of iron deposits. Introduction: Baba-Ali and Galali deposits are located in 30 and 60 km northwest of Hamedan in northwest part of the Sanandaj-Sirjan zone. The host rocks of these deposits are metavolcano-sedimentary successions of Songhor series in Permo-Triassic age. Stratigraphic position of ore horizons, geometry of orebodies, ore structures and textures in different scales and paragenetic sequence of minerals all show close genetic relation between iron ore and the metavolcanosedimentary and subvolcanic rocks. The host rocks in the area are felsic to intermediate metavolcanic rocks, more than lava and rhyolitic tuffs with interculations of carbonate and metatuff-sandstones. Field observations and petrography show that emplacement of plutons and subvolcanic rock units with composition of gabbrodiorite, quartzmonzodiorite, granodiorite, syenite, syenogranite and granite in these successions caused deformation and metamorphism of ore and country rocks. Materials and methods: In this research, 56 polished sections were prepared from iron ore of Baba Ali and Galali deposits, and the mineralogical characteristics and texture of the mineral in relation to gangue minerals were carefully studied using a reflected light mineralogical microscope. In order to determine the origin of ore-rich fluid, studies of fluid inclusions have been carried out on 6 double polished sections in the research laboratory of Tarbiat Modares University. Also, 29 samples of separated phases of sulphide, oxide-silicate and carbonate minerals from ore and gangue minerals of Baba Ali and Galali iron deposits have been analyzed for stable isotope analysis in Queen's University Isotope Research Laboratory in Canada. Results and discussion: From field evidences, fluid inclusions data, as well as stable isotope analysis in this study, emplacement of plutons and subvolcanic rock units with composition of gabbrodiorite, quartzmonzodiorite, granodiorite, syenite, syenogranite and granite in these successions caused deformation and metamorphism of ore and country rocks. Fluid inclusion studies within the quartz crystals indicate that main salinity varies between 12±5 and 9±5 wt.% NaCl equivalent in Baba-Ali and Galali deposits respectively. Homogenization temperature for Baba-Ali and Galali deposits are 226±5 and 220±5 oC respectively. Occurrence of dynamothermal regional metamorphism in these deposits typically involves a lengthy period of time, during which there was a tendency toward isotopic homogenization specifically in O (3 to 10.5 ‰) and H (-10 to -35 ‰) stable isotopes and show the role of metamorphic waters in mineralization process. Measurement of δ34S (CDT) in first generation of pyrite is higher than another one, so these data confirm the volcano-sedimentary origin of primary iron mineralization. Conclusion: Field observations, structure and texture, host rock, intercualation, geochemistry, alterations, studies of fluid inclusion and stable isotopes in Baba Ali and Galali deposits show that these deposits are volcanic-sedimentary iron deposits. Since most of these mineralizations are located in metamorphosed volcanic-sedimentary units, these rock groups are of great importance in terms of iron exploration. Investigating these stone units in the region and generalizing the evidence obtained from them to similar areas in Sanandaj-Sirjan zone can lead to the identification of this type of iron deposits.

https://esrj.sbu.ac.ir/article_101329_c5e348ddd390ebc319d012348ff9ad4a.pdf

Shahid Beheshti University Researches in Earth Sciences 2008-8299 14 2 2023 08 23 Lithostratigraphy, biostratigraphy and diagensis of the Ruteh Formation, south of Amol Lithostratigraphy, biostratigraphy and diagensis of the Ruteh Formation, south of Amol 143 158 100785 10.48308/esrj.2023.100785 FA Ali Reza Chegini Department of Geology, Faculty of Sciences, Lorestan University, Khorramabad, Iran Iraj Maghfouri Moghaddam Department of Geology, Faculty of Sciences, Lorestan University, Khorramabad, Iran 0000-0002-4000-8571 Mohamad Hossein Adabi Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran 0000-0002-6679-3678 Masoud Lotfpour Department of Geology, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran Journal Article 2019 03 12 Introduction: During the Early Permian, mostly mixed siliceous sediments Carbonate-debris of Droud formation was mainly deposited in continental and intermediate environment, with increasing depth gradually in the late Permian, Middle Permian and early Permian of Ruteh Formation with carbonate facies and then in the late Permian. Ruteh formation was identified and introduced for the first time by Assereto (Assereto, 1963) in the valley of Ruteh village in the northeast of Tehran. in this study of Ruteh formation based on detailed lithological characteristics (macroscopic and microscopic) and identification of benthic foraminifera in a stratigraphic section 30 km south of Amol in central Alborz, in terms of rocks Stratigraphy and biostratigraphy have been investigated. Materials and methods: After preparing microscopic thin-sections from all samples, the sections were stained with red alizarin solution according to Dickson's method (Dickson, 1965) to distinguish calcite from dolomite and then studied under a microscope to identify microfossils. After the identification of microfossils, the bio zonation of the sediments of Ruteh Formation was started based on the biozone of Leven and Okay (1996) belonging to the West of Paleo-tethys. Results and discussion: In the biostratigraphic studies of the Ruteh formation in the stratigraphic section of South Amol, whereas 31 genera and 57 species of benthic foraminifera were identified, three local biozones were identified and introduced as described below. Small Foraminifera and Fusulinids together with green and red algae constitute the most important microfossils of Ruteh formation. Neoendothyra bronnimanni-Neoendothyra reicheli assemblage zone This biozone, which is an accumulation type, is defined based on the existing symbiotic community in it, and it occupies 72 meters from the base of the Ruteh formation after the erosion boundary between the Dorud and Ruteh formations. The age of this biozone based on its identified species such as various species of Neoendothyra and the comparison of this cumulative biozone with Khachik Julfa layers and other areas of the Tethys region such as Afghanistan indicates the late Murgabian age for this zone. Chusenella sinensis - Codonofusiella erki - Pachyphloia sp. assemblage zone This cumulative biozone includes 282 meters of the thickness of Ruteh formation after biozone 1. The age of this formation is based on the presence of foraminifera such as Chusenella sinensis and the comparison of this accumulation biozone with midian foraminifera of Khuf Formation Paraglobivalvulina mira - Dagmarita chanakchiensis assemblage zone This biozone, which is defined based on the following symbiotic complex, inhabits 288 meters from the top of the Ruteh Formation in the studied section. Based on the symbiont complex, the age of this biozone has been identified as the early Julfian. Conclusion: The thickness of the sediments of Ruteh formation in this section is 642 meters and in terms of lithology, it mainly consists of thick to medium and thin dark limestone along with dolomitic limestone, limy dolomite, sandy limestone, cherty limestone, shale and sandstone. The lower boundary of Ruteh Formation with Dorud Formation is disconformity. Its upper border is also with the Nesen Formation, which is discontinuous and eroded along with a laterite horizon. Based on the above biological zones and the set of fossils identified in them, the age of the Late Murgabin-Early Julfian Ruteh formation was determined. Introduction: During the Early Permian, mostly mixed siliceous sediments Carbonate-debris of Droud formation was mainly deposited in continental and intermediate environment, with increasing depth gradually in the late Permian, Middle Permian and early Permian of Ruteh Formation with carbonate facies and then in the late Permian. Ruteh formation was identified and introduced for the first time by Assereto (Assereto, 1963) in the valley of Ruteh village in the northeast of Tehran. in this study of Ruteh formation based on detailed lithological characteristics (macroscopic and microscopic) and identification of benthic foraminifera in a stratigraphic section 30 km south of Amol in central Alborz, in terms of rocks Stratigraphy and biostratigraphy have been investigated. Materials and methods: After preparing microscopic thin-sections from all samples, the sections were stained with red alizarin solution according to Dickson's method (Dickson, 1965) to distinguish calcite from dolomite and then studied under a microscope to identify microfossils. After the identification of microfossils, the bio zonation of the sediments of Ruteh Formation was started based on the biozone of Leven and Okay (1996) belonging to the West of Paleo-tethys. Results and discussion: In the biostratigraphic studies of the Ruteh formation in the stratigraphic section of South Amol, whereas 31 genera and 57 species of benthic foraminifera were identified, three local biozones were identified and introduced as described below. Small Foraminifera and Fusulinids together with green and red algae constitute the most important microfossils of Ruteh formation. Neoendothyra bronnimanni-Neoendothyra reicheli assemblage zone This biozone, which is an accumulation type, is defined based on the existing symbiotic community in it, and it occupies 72 meters from the base of the Ruteh formation after the erosion boundary between the Dorud and Ruteh formations. The age of this biozone based on its identified species such as various species of Neoendothyra and the comparison of this cumulative biozone with Khachik Julfa layers and other areas of the Tethys region such as Afghanistan indicates the late Murgabian age for this zone. Chusenella sinensis - Codonofusiella erki - Pachyphloia sp. assemblage zone This cumulative biozone includes 282 meters of the thickness of Ruteh formation after biozone 1. The age of this formation is based on the presence of foraminifera such as Chusenella sinensis and the comparison of this accumulation biozone with midian foraminifera of Khuf Formation Paraglobivalvulina mira - Dagmarita chanakchiensis assemblage zone This biozone, which is defined based on the following symbiotic complex, inhabits 288 meters from the top of the Ruteh Formation in the studied section. Based on the symbiont complex, the age of this biozone has been identified as the early Julfian. Conclusion: The thickness of the sediments of Ruteh formation in this section is 642 meters and in terms of lithology, it mainly consists of thick to medium and thin dark limestone along with dolomitic limestone, limy dolomite, sandy limestone, cherty limestone, shale and sandstone. The lower boundary of Ruteh Formation with Dorud Formation is disconformity. Its upper border is also with the Nesen Formation, which is discontinuous and eroded along with a laterite horizon. Based on the above biological zones and the set of fossils identified in them, the age of the Late Murgabin-Early Julfian Ruteh formation was determined.

https://esrj.sbu.ac.ir/article_100785_6c47072b4eb5875d47001a1001aba984.pdf