نشریه کواترنری ایران
پیاپی 27 (بهار و تابستان 1401)

Global warming refers to the recent and ongoing rise in global average temperature near Earth's surface. It is caused mostly by increasing concentrations of greenhouse gases in the atmosphere. Global warming is causing climate patterns to change. However, global warming itself represents only one aspect of climate change. (Nakicenovic et al., 2000; Bytnerowicz et al., 2007).Over the past century, human activities have released large amounts of carbon dioxide and other greenhouse gases into the atmosphere. The majority of greenhouse gases come from burning fossil fuels to produce energy, although deforestation, industrial processes, and some agricultural practices also emit gases into the atmosphere.Greenhouse gases act like a blanket around Earth, trapping energy in the atmosphere and causing it to warm. This phenomenon is called the greenhouse effect and is natural and necessary to support life on Earth. However, the buildup of greenhousegases can change Earth's climate and result in dangerous effects to human health and welfare and to ecosystems. 

In this study, daily precipitation and daily maximum (Tmax) and daily minimum (Tmin) temperatures in the Kahnuj synoptic station, southeastern Iran were predicted for the future (2061-2080) by statistical downscaling outputs of 5 GCM models (EC-EARTH, GFDL-CM3, HadGEM2-ES, MIROC5, MPI-ESM-MR) under RCP 4.5 and RCP 8.5 emission scenarios.

The results of statistical downscaling outputs of 5 GCM models by LARS-WG model under RCP 8.5 emission scenarios (the business-as-usual) in Kahnuj station was modeled from 2061–2080. During this period the mean temperature will increase between 3.2 to 4.6 °C compared to the base period.At The Paris Agreement, the average increase in temperature was set at below 2 °C by the end of the 21st century, which includes the 0.9 °C increase Since the Industrial Revolution, to avoid adverse and unpredictable weather effects (IPCC, 2021; Millar et al., 2017; Rogelj et al., 2018). However, the results of this study show that southeastern Iran is firmly set on the path by increasing the current temperature by several degrees more by 2080. Based on the two modeled scenarios, the change in temperature will have an increasing trend in the coming years and is in good agreement with the recent assessments of future temperature changes in southwest Asia (Babar et al., 2016; Hamidianpour et al., 2016; Pal et al., 2016; Evans, 2009). Therefore, if greenhouse gas emissions continue at their present rate, earth's surface temperature in this region will pass the temperature threshold of 2 °C.

We compare simulated future precipitation based on RCP 4.5 and RCP 8.5 scenarios of global warming with real paleoclimatic changes that happened in the region. In this respect, the maximum and minimum temperatures and precipitation projection in the southeastern Iran is derived from the downscaling of the CMIP5 GCMs (EC-EARTH, GFDL-CM3, HadGEM2-ES, MIROC5, and MPI-ESM-MR) under RCP 4.5 and RCP 8.5 using the Lars WG model. Paleoenvironmental records from southeastern Iran is used to examine whether the predicted changes in precipitation and variability in MLW output based on the two scenarios of global warming are valid.GCMs predicted a considerable decrease in MLW precipitation in Kahnuj station. Similarly, HadGEM2-ES and GFDL-CM3 indicate a weak decline in precipitation compared to other GCMs at the Kahnuj station for RCP 8.5.The current study indicates that in the Jazmurian playa, MLW precipitation will decrease, and temperature will increase in future simulations. Infact, Consistent with several GCM studies and real paleoclimatic changes that happened during past warm/wet periods in the region, results emerging from the Jazmurian playa also show a weakening of the MLW under the RCP 8.5.

The study and measurement of landscapes and forms created by active tectonics are considered important issues of geomorphology. Active tectonic movements of a region are recorded in the morphology of rivers, drainage of waterways, alluvial cones and mountain fronts. Jabal Barez fault is located in the north of Jiroft plain in the south of Kerman province, which is active from a tectonic point of view. Due to the operation of the Jabalbarz fault in the region, a specific morphology has been created in the northern slopes of Jiroft Plain, which can be used to identify different parts of this fault. Geomorphological indicators are a useful tool in the evaluation of new tectonic activities in regions. The important advantage of these indicators is the high speed in analyzing and determining the level of new land construction activity. The main goal of this research is to investigate the active tectonic activity of Jabalbarez fault using morphotectonic indicators (SL, S, Smf, Facet%, VF). The results obtained from the morphotectonic indicators indicate the continuation of neo-tectonic movements and uplift in the study area, which are consistent with the geomorphological evidence in the study area, such as the presence of linear and straight fault cliffs, triangular shapes, deep and V-shaped valleys.

Damghan area has been considered by earth scientists due to the existence of numerous active faults. These faults with slow and progressive movements have led to changes in the shape of landforms in the area. Even during the history, the activity of these faults led to major earthquakes such as Qumis earthquake in 856 A.D. This earthquake led to the complete destruction of Qumis province in present-day Damghan. Researchers in the area, including Hollingsworth et al 2010., have concluded that major faults in the area, such as the Astaneh and North Damghan faults, have ruptured during the Qumis earthquake. The changes in landforms and high potential of faults in creating seismic events indicate their continuous activity during Quaternary up to now. To study these changes, we need those features that are sensitive to tectonic and erosive events. Rivers are one of these features that react quickly to active tectonic and erosion changes. The main purpose of this study is investigation of the changes in landforms using anomalies in stream orders. Because there is a hypothesis that claims tectonic and erosive changes lead to irregularity in Strahler orders of streams. In this study we use isobase and differential map method to investigate this hypothesis.

Sensitivity of drainage network to tectonic processes and geological contradictions leads to changes and irregularities in river orders. Isobase maps are extracted from information about the spatial classification of rivers and their elevation information in the environment. In fact, these maps show the relationship between the pattern of waterways and the topography of landscapes. Streams with the same Strahler order are formed by the same geological events, and most likely the same order is the same age. We can draw iso base maps for different stream orders. Early orders (1-3) are mostly more sensitive to tectonic events. These early orders due to flow along seams and fault gaps are representative of neotectonic. Rugged structures in the lithology of the region can limit the evolution and development of the early orders, and therefore in these areas the values of the isobase map increase. But isobase map of evolved orders can represent longer periods, such as the Quaternary or Pleistocene. Because evolved orders are formed over longer periods and are able to show older tectonic and erosive events. Differential maps are obtained from the difference in height between the maps of the evolved orders and the present day topography map.

Examination of the isobase map of the primary orders show that most of the values related to the map can be seen in the west and north of the region. These areas are based on mountainous structures. The high values of the isobase map in these areas indicate that the northern and western parts, affected by neotectonic activities and the development of fault gap and seams, have more primary orders of rivers. Because most of these primary orders are formed and developed along these levels of weakness. Resistant lithology of the area has also prevented the development of these orders. The highest value of them is 3830-2312 meters. The differential map prepared from the study area shows a wide range of positive values indicating uplift and negative values indicating subsidence. By examining these values, we can understand the features related to tectonics and geomorphology of various landforms in the region. The highest values of 1191 to 800 meters are related to the high mountain structures of Eastern Alborz in the north and west of the region. The decrease in the value of the differential map indicates the effect of tectonic subsidence on the morphological landforms of the region. The Astaneh pull apart basin in the western part of the region shows the amount of subsidence between -4 to -1 meters. Also, the southern playa of Damghan in the form of a concave foreland basin affected by active faults in the region shows negative values, which indicates the existence of a submerged basin with high sedimentation potential.

Studies conducted on the area show that the two factors including active tectonic and lithology have a great impact on the morphological structures and landforms of the area. The results of isobase map and the differential map show and confirm this issue. The methods used in this study to investigate the tectonic activity of the faults in the area indicate their activity during the Quaternary. These faults have different mechanisms of thrust and streak slip which in some areas also have transtensional and transpressional position; they have created a collection of uplifted or concave landforms in Damghan area. The spatial relationship between different values from north to south in the prepared maps indicates the creation of an equivalent states between topographic growth and its destruction in lower altitudes. Based on the studies, we confirm that the preparation of isobase and differential maps can be a suitable method for studying and examining morphological structures. Also studies related to differential map show anomalies in drainage networks and uplift processes associated with active Quaternary landforms can be quantified by these maps. Using baseline and differential maps is one of the appropriate methods to study the Plio-Quaternary tectonics in an area. This study confirms the work of previous researchers based on the available information and documents related to the study area.

Climate, as the average temperature or precipitation over a long period of time, has been constantl  fluctuating and changing, and there is no simple relationship between climate change and human biological and cultural reactions.Understanding the environmental characteristics of the past is important to understand climate changes.Climate changes are reflected in the physical and chemical characteristics of sediments, which can be used to understand sedimentary processes and ancient sedimentary environments.In the meantime, the sediments of playa lakes are sensitive indicators of local climates And due to the influx of large volumes of sediments during floods and as a result of the high rate of sedimentation, it is possible to record climatic and environmental changes with high resolution. Jazmurian playa in the southeast of Iran consists of sand, mud and salt flats. Over time, under the influence of water and wind processes, Jazmurian has left various deposits in deltaic, lake, playa and wind environments.

Jazmourian plateau between latitudes 58˚-40' to 59 ˚-14' and latitudes 27˚,10' to 27 ˚, 41' in southeastern Iran and west of Sistan and Baluchestan province and east of Kerman province. It is located at an altitude of about 360-500 meters above sea level. The catchment area is about 69,600 square kilometers, of which about 34,160 square kilometers are mountainous areas, 32,440 square kilometers are plains and foothills, and the remaining 3,000 kilometers are swamps and salt marshes. For this study, intact sediment cores were used to reconstruct the Paleo climate. Five sedimentary cores with a maximum depth of 7 m and a total depth of about 30 m were collected and investigated from the sediments under of different areas of Jazmourian Playa using a hand-held core. Sedimentary facies were identified and distinguished based on sediment texture and composition, composition of destructive sediments and organic matter, color, presence of plant and shell residues, and other macroscopic components. According to sedimentological studies and changes in sedimentary facies, eight separable sedimentary facies belonging to river, playa, lake, delta and wind environments were identified. To estimate the time of climatic events in the region, the results of the survey of Vaezi et al. (2019) were used.

In order to reconstruct the environmental and climatic conditions of Jazmurian playa by using the geochemistry of sediments, 5 sediment cores were taken from the inner part of the playa. Coring was done by manual auger to a depth of about 7 meters. In taking the cores, the changes of sedimentary facies were recorded based on macroscopic evidence such as the type of layering surfaces, the geometric shape of sediments, sedimentary structures, animal remains and contents, plant remains, the presence of evaporite minerals, the relative degree of hardness, color and its changes. Reconstruction of the spatial distribution of different sedimentary environments and their displacement and conversion to each other was done based on the data of sedimentary cores in different areas and finally the stratigraphic column of the studied cores was drawn. Half of the collected samples were taken to the laboratory for preparation and chemical analysis, and the other half was archived at 4°C. A total of 19 sediment samples from a core (comprehensive core) were sent to the laboratory of the Geological and Mineral Exploration Organization of the country for chemical analysis. Varian 735-ES model ICP-OES (ICP Optical Emission Spectroscopy) device was used for elemental analysis and the results of the anomaly level of 54 other elements in terms of ppm were identified by the ICP device. In the studied cores, the relative changes of elements in different time periods are very high, this situation indicates the presence of severe changes in the sedimentary sequence of Jazmurian playa bed. This study provides a breakdown of environmental and climatic changes in the southeastern region of Iran during at least the last 20 thousand years. In this research, climatic and environmental events have been identified in the sedimentary sequence taken from Jazmurian playa according to elemental anomalies and 8 elemental ratios. The elemental ratios of Mn/Al and K/Al as an indicator of chemical weathering changes in the watershed in the period of 20 thousand years are changing between 0.0154 to 0.0135 and 0.226 to 0.252, respectively. An increase in these ratios indicates the existence of favorable conditions for increasing the amount of chemical weathering in the watershed and a corresponding increase in humidity and temperature, and its decrease indicates the presence of dry conditions in the basin.

Sedimentological investigations, statistical parameters of sedimentology and sedimentary facies of the cores taken from Jazmurian playa led to the identification of five sedimentary environments including wind, fluvial, deltaic, lake and playa sediments in Jazmurian basin. The sedimentation rate in Jazmurian playa is different in different depths, this rate reaches 0.01 mm per year in the surface parts. The average sedimentation rate in Jazmurian playa is about 0.4 mm per year. V/Cr, Mn/Al, K/Al, Fe/Ca, Ti/K, Ca/Mn, Ca/Sr, Fe/Al element ratios to reconstruct the climatic and environmental conditions, the amount of debris (clay sediments and wind deposits) The input to the basin, the severity of weathering and erosion in the catchment basin and the fluctuations of the lake water level indicate the climatic condition of Jazmurian region in two time periods. The time period of the late Pleistocene when suitable humid conditions prevailed. During this period, the amount of chemical weathering in the catchment area and sediment load to the playa has been significantly high. Since the beginning of the Holocene, climatic and environmental fluctuations have increased in the basin, and until the beginning of the middle Holocene, there has been a gradual decrease in humidity, with the beginning of the middle Holocene, this process has accelerated, and wind-blown sands have entered the northern and western parts of Jazmurian playa. From the beginning of the middle Holocene until now, according to the investigation of sedimentary facies and elemental ratios, at least two dry periods in 8200 and 4200 years ago can be identified and traced.

Lake basins have spatially and temporally index patterns and represent valuable maps of physical and chemical history. According to this point, that direct survey of climate changes has only been available as machinery in the past few decades, so past’s climate changes indexes can give a better understanding of climate changes in the past era and its causes. Of these, lake sediments have an extraordinary ability to record climatic and environmental events with high sensitivity and resolution and very high- resolution amounts. Therefore, lake sediments can be considered as regions for detecting paleontological environments. Abzalou lake formed in the northeast of Khuzestan province on the hillsides of folded Zagros and under the Izeh unit in a pit. This study has been tried to by Sedimentary geochemistry examination, Elemental ratios, identification of sedimentary facies, identification of sedimentary environments and changes of these environments set to the reformation the climatic and environmental conditions of Abzalou wetland in the end Holocene.

The steps of this research include book studies, field works, laboratory works, data processing and then interpretation and conclusion. To investigate the paleontological climate and conditions of the sedimentary environment, 8 intact sediment cores with a maximum depth of 7.5 m and total of 35 m collected with using Auger corer. 36 sediment samples from 2 cores were selected for elemental analysis with ICP-OES and XRF (X-Ray fluorescence). Also, 3 samples were analyzed by C14-AMS isotopic method. Statistical parameters, histogram diagrams of element frequency and cluster analysis were performed to determine the relationship between the elements in SPSS software. In this study, according to the studies, elemental ratios of V/Cr, Mn/Al, K/Al, Rb/Al, Si/Fe, Ti/K were used to reconstruct the climatic and environmental conditions. Which led to the study of the amount of detrital material, the severity of weathering and erosion in the catchment and fluctuations in the water level of the lake.

In the studied cores, 8 major sedimentary facies identified. Facies often contains clay, silt, sand, gravel, and interstitial sediments along with vegetation and shell fossils which in most cases frequency and interference in the mentioned sediments are often seen. Changes were in particle size between clay to gravel due to process type changes, environment's energy and river input's amounts and sediment color variations concerning sedimentation conditions, presence of organic matter, pH amount, salinity and temperature variations, and drought occurrence, throughout the cores. Three wetland sedimentary, river and alluvial environments identified. According to the age measurement, the average sedimentation rate in the Abzalou wetland is 1.22 mm / year, which this amount is different for various depths. Due to the type of sediments, the Abzalou wetland has undergone human changes for about 600 - 500 years ago. The high water period of the Abzalou wetland has been established between 1800 and 500 years ago. The study of the facies sediments of the wetland bed shows that climate change occurred gradually (not suddenly) about 1800 years ago and this trend has taken at least 200 years. The relatively dry period lasted about 700 years from 2500 years to 1800 years ago and is confirmed with the reported dry periods in the Maharlou lake about 1800 years ago, in the Mir Abad lake about 1500 years ago and in the Urmia lake between 2500 and 1500 years ago. From 4400 years ago to about 2500 years ago, stable and slow wetland conditions prevailed. The conditions for creating a peatland environment have been provided in the wetland and were associated with increasing the amount of organic matter, vegetation and shell fossils and consequently increasing sedimentation rate. This period which lasted for about 1900 years, has been accompanied by extremely humid conditions, high groundwater level and activity of springs feeder in the region. The existence of light brown mud which has the age ranges from 4400 to 4700 years ago, indicates a dry period (300 years). This dry period shows suitable approximate conformity with a dry event of 4200 years ago in the northern hemisphere. This period in the studied region appeared with at least 200 years of temporal delay. After this dry period, we see again a gray sequence with plant and shell fossils that continue to a depth of 7 meters (about 5300 years ago). At depths of 7 to 7.5 m, the existence of brown-muddy sediments along with coarse-grained sediment in size of gravel, pebble and rubble, strengthen the possibility of very strong flood in the region that sent the coarse-grained sediments of around formation to bed of the wetland or maybe has hit to the area of wetland sediments bed in the region.

According to the results of surveys in the Abzalou wetland, at least 3 high water periods with humid climate and at least 2 dry periods during the Late Holocene were identified.  Dry periods appear more suddenly and with more intensity and shorter duration than humid periods in the region and gradually lead to from very dry periods to semi-arid, semi-humid, and eventually humid periods.

Human societies have always been influenced by climatic and geographical factors of their ecosystems throughout history, so interdisciplinary studies to identify these influences will help to understand the cultural changes of ancient societies. One of the geographical factors affecting the ancient sites of the northern regions of the country is the Caspian Sea. The separation of this lake from the high seas has caused the sea level of this sea to increase slowly and when it reaches its maximum height, it decreases with the same rate. In this study, an attempt has been made to combine the information obtained from marine sediment survey studies with archaeological evidence and findings, as far as possible, to investigate the effects of Caspian Sea water regressions and advances on the location of prehistoric settlements in the Mazandaran region of The Paleolithic period to the Iron Age. For this purpose, studies on the altitude range of these changes were reviewed and the results obtained in the field of paleontology of Caspian Sea level fluctuations were combined with the results of archaeological studies in the region. Simultaneously with the fluctuations of the Caspian Sea water during the Pleistocene and Holocene, the location of prehistoric sites and populations on the southern shores of the Caspian Sea changed relative to seawater, and with the advance of seawater, the remains of previous evidence are buried under sediments.

The Caspian Sea is the largest lake in the world and has nothing to do with open waters, and its water is supplied by rivers that flow into it. The water level of this lake is a dynamic phenomenon and its oscillating amplitude has different intensities in time scales. Fluctuations in the water level of the Caspian Sea are subject to various factors such as changes in the runoff of rivers leading to the sea and the intensity of evaporation and undoubtedly affect the coasts and the distribution of existing settlements in them. In each of the advances, the water of the Caspian Sea rose to such an extent that it submerged parts of the lowlands of northern Iran. The morphology of the coast is very different in response to these fluctuations and has a wide range of features based on the slope of the coast and the sea to land. It is natural that the advancement of water level will have the greatest impact in the parts of the Caspian Sea that have less depth and less in the areas that have more depth. 800 km south coastline of the Caspian Sea is divided into 4 categories based on the type of response to fluctuations. It is a steep beach. While the changes in coastal morphology in the western coasts of Mazandaran have not been very noticeable, its southeastern regions are one of the areas sensitive to water level. Studies and measurements of marine sediments and their combination with archaeological evidence and findings are effective in recognizing the effects of backwaters and advances of the Caspian Sea water on ancient sites. These effects can be traced back to the Khvalyian and Neo-Caspian cycles, which archaeologically continue from the Paleolithic, Late Paleolithic, Neolithic, and prehistoric and historical periods to the present. The Old Paleolithic period coincides with the Caspian cycle, in which the advance of sea water with a level of -20 to -15 meters occurred about 300 to 250 thousand years ago.

The Middle Paleolithic period coincides with the Khvalyian cycle, which itself coincides with the last temperate glaciation and the dissolution of ice sheets at higher latitudes. Since the largest Quaternary advance in the Khvalyian cycle occurred with a water level of 48 to 47 meters, so the southeastern shores of the Caspian Sea due to its gentle slope during these advances below The water is gone and it seems that the Middle Paleolithic sites, which were located at low altitudes and close to the sea, were buried during the advance of the water. Noshahr dam area is located at an altitude of 400 meters above sea level in the western part of Mazandaran with a steep coastal slope and therefore has the least impact from the fluctuations of the Caspian Sea water level. The Neolithic period coincides with the period between the Lower and Upper Khavalyian, the water level of the Caspian Sea has receded by about 110 to 120 meters, and evidence for this period may have been buried following further advances. Towards the end of the Pleistocene and before the beginning of the Holocene (11550-10550 years ago), the water level of the Caspian Sea decreased by 100 meters, which coincides with the abundance of extra-Paleolithic settlements on the southeastern coast. With the beginning of the Holocene period in 10,000 years ago, the water level of the Caspian Sea reached an altitude of -22 meters. The first Neolithic settlements of the region were formed in low plains near the coast and at a distance of less than two kilometers of surface water. Around 7000 BC, the water level of the Caspian Sea reached -25 meters. And in the millennium 6000 BC, the water level of the Caspian Sea was -28 meters and was at the lowest level since the beginning of this period. During the Chalcolithic, in the fifth millennium BC, the water level of the Caspian Sea increased to -20 meters above sea level, and during one millennium, at 4000 BC, it decreased by one meter and reached -21 meters. The most important settlements of this period have been identified in the mountainous plains. Around 3000 BC, the water level of the Caspian Sea was about -35 meters above sea level, so the coastline, especially in the south and southeast of the Caspian Sea, was far behind today. At this date, which coincides with the Bronze Age, the greatest decline in seawater occurred during the Holocene, and of course the position of many human settlements relative to the coastline has changed. However, the greatest advance of the Caspian Sea water level was during the Holocene period - 20 meters, which occurred in 1300 AD, and with the advent of water, the evidence of many ancient settlements was washed away and buried under sediments. Perhaps this is why the remains of Iron Age sites in the low plains of Mazandaran are small. In general, humans at different times tried to choose the most accessible place to the sea for settlement, and with the retreat and advance of sea water, the location of settlements changed. Previous settlements were buried following the advance of seawater. Undoubtedly, in order to fill information gaps about different prehistoric periods in the field of research, the effects of these fluctuations must be considered. The study of water fluctuations in the Caspian Sea is important in analyzing the behaviors of ancient populations and their settlement patterns.

Azerbaijan Plateau is a part of the Alpine-Himalayan fold and orogeny belt, which is located in a compressional regime and between Talesh Mountains, south of Lesser Caucasus Mountain, east of Anatolia, north of Zagros Mountain. The studied area has located in the geographical longitudes of 47° to 48° and latitudes of 38° to 39° in East Azerbaijan province. There are wide ranges of Plio-Quaternary basalts and andesite basaltic in the sheet of 1.250000 Ahar. These rocks are gray to black in color. They also are formed of lava flows with scattered sometimes prismatic structures on the Paleocene andesitic lavas or conglomerate, siltstone and red marl Pliocene.

After the field investigations, we were taken 30 fresh and unaltered samples. Then, they were prepared as a thin section, then go undrer petrographic studies with a microscope in the laboratory.  Finally, we selected 10 samples were sent to the Amdel laboratory in the Australia for chemical analyses by ICP-MS, and OES.  Consequently, the results of whole rock chemical analysis data, were processed by GCD-KIT software. Then, all data were interpreted by geochemical conditions of all analyzed samples and also with their tectonic environment in the area.

The studied area is a part of the lesser Caucasus mountain range with high deformation and seismicity, which has located in a crustal convergence in the northwest of Iran. This area has a faulted system and with active strike-slip faults (Kocyigit et al., 2001). These systems often coincided with previous crustal discontinuities and have been widely effective in generating Quaternary magmatic activities locally through pull-part zones (Shabanian et al., 2012; Avagayan et al., 2010). Almost all the Quaternary magmatism in the region has occurred due to the operation of these fault systems and in the tensile position of the continental crust. Therefore, active fracture and fault systems and even old hidden faults have played a major role in the occurrence of the Quaternary magmatism.Volcanic rocks of the studied area are hyalo-aphanitic to hyalo-microlithic porphyry texture with large crystals of olivine, plagioclase and pyroxene. Also, porphyry, trachyte, intersertal and intergranular texture canbe seen in these samples. These samples have the nature of basaltic, thrachy andesite, mojearite and dacite, which are located in a calc-alkaline range. These rocks are rich in LREE and depleted in HREE.They also have enriched of Cs, Th, Pb and depletion of Ba, Nb, Eu, La. The presence of garnet in the source of magma can indicated the involvement of processes and crystallization of olivine, pyroxene, and plagioclase. In addition, metasomatism or contamination with enriched crustal materials (Menzies & Wass, 1983) leads to the abundance of LREE elements. Therefore, the metasomatized mantle can be a suitable origin for the magma of the studied volcanic rocks. Enrichment of elements Cs, Rb, Pb, Ba, LILE and depletion of elements HFSE (Nb, Zr) indicated the magma of subduction arc zones (Wilson, 1989). The negative anomaly of Nb, P, Ti, Zr and the positive anomaly of Pb are the characteristics of crust contamination of quaternary basalts (Wilson, 1989; Hofman, 1997). Negative Nb anomaly is characteristic of continental rocks and crustal involvement in magmatic processes (Hofman, 1997). Also, the negative anomaly of Ti and Nb in the normalized pattern with primary mantle composition can indicate magmas related to subduction (Pearce, 1983; Wilson, 1989). All the samples are in the range of intraplate basalts (Figure a10) (Mesched, 1986), and show the orogenic situation (Pearce et al., 1977). The studied volcanic samples are volcanic arc (Muller et al., 1992) belong to the continental arc after the collision (Groves, 1997).  Also, the studied samples show the origin of lherzolite garnet mantle and lherzolite spinel with a rate of 2 to 5% of partial melting.The tensile positions of the continental margins are active, where partial melting has occurred due to pressure reduction and rupture of the subcontinental lithosphere. Its compressive force resulting from crustal collision and crustal shortening, thickening and uplift leads to disturbance of subcontinental lithosphere thermal levels in these regions. Therefore, it seems that since the Eocene, the post-collision regime (Omrani et al., 2008) and since the Miocene (Hasanpour, 2008) has been ruling in the Arsbaran.

The Quaternary volcanic rocks in the eastern part of Ahar area, include a set of basaltic, andesite basaltic and andesite with calc-alkaline nature. The special depletion and enrichment of rare earth elements, these rocks are very similar to enriched mantle magmas and OIB, which were formed in the volcanic arc environment after impact on the active continental margin. For these samples, the mantle origin is lherzolite garnet to lherzolite spinel with 1 to 10% partial melting. Also there were happened metasomatisms of subducting oceanic lithosphere fluids. The geochemical evidences show some degrees of crustal contaminations during magma ascent. This magmatism has occured due to the subduction and the system of faults and fractures of the region and the tension tectonic situation. This tension system in the active continental margin after the collision has led to a decrease in pressure and finally the pouring out of basaltic magma.

Paleoclimate is a new branch of science that investigates the climate changes of the past by using different sciences. Carbonates are a type of rocks that have been studied a lot in the geochemistry of stable isotopes and are found in all time intervals. A common type of carbonate rock is speleothem, which is capable of providing reliable records of climate change over many years. The studies conducted in the last decade show that the past climate can be understood by δ18O and δ13C. One of the common forms of speleothem is stalagmites, whose layers are known as a potential source of high-quality climatic information. By using speleothem, it is possible to reconstruct the climatic conditions up to about 600 thousand years ago. Comprehensive and complete information is not available about the climatic and environmental conditions of Iran during the Holocene period. Meanwhile, Iran's location as a transition zone between Europe, Asia and Africa is of great importance for study the past climate; However, compared to other regions, it has been less studied, which has provided a special position for this research. In the present research, it is intended to be analyzed with the help of the information received from a cave in the Zagros region of the past climate of Iran.

For paleoclimate analysis in central Zagros, Maghar cave in Khorramabad (located in Lorestan province and in Karkheh watershed) was selected. The condition of this cave is such that it has little connection with the environment outside the cave and is not affected by the wind and other meteorological parameters outside the cave. After evaluating inside the cave, a stalagmite with a length of about 18 cm and a diameter of 8 cm was selected. After cutting it, it was transferred to the soil mechanics laboratory of Lorestan University, where its surface was polished in order to observe the layers. Since the primary core of the stalagmite is not located right in the center, it can be concluded that the primary bed of stalagmite formation is located on a sloping surface, which caused the drop of water to move on the sloping surface after hitting the surface of the cave. As the limit has increased in length, it has grown in width. For dating, three points were considered, including the stalagmite primary core (D1), middle (D2) and on top of it (D3). Age measurement was done by Multi-Collector Inductively Coupled Plasma-Mass Spectrometer (MC-ICP-M) located in the laboratory of the University of Queensland, Australia. For stable isotope analysis, 34 samples were sent to Arak laboratory for δ13C and δ18O analysis, and the analysis was done by Isotope Ratio Mass Spectrometer (IRMS) (30 samples in the direction of stalagmite growth length and 4 other samples for Hendy test). According to the standard of this device, 50 mg of powder was prepared for each sample. This was done with the help of a dental drill and movement on the stalagmite layers. To determine the percentage of calcite and aragonite, 4 samples (50 grams each) were sent to the laboratory of Lorestan University for XRD testing.

According to the XRD results, the percentage of aragonite was considered zero for all four samples. According to the Hendy test, stalagmites are formed in isotopic equilibrium conditions. The age of three samples was estimated to be 550, 368 and 8.6 thousand years respectively. The analysis of δ18O isotopic results over time showed that the isotopic data is increasing with a relatively large slope, which indicates that the conditions of the studied area during the last 550 thousand years are becoming

Climatic periods are always changing and dry and wet periods have occurred on a larger scale in the form of glacial and interglacial periods. In the past, these changes happened very slowly, but in the last 5 thousand years, the changes are fast. These changes intensify over time. So that there have been sudden changes in the last hundred years. Today, climate change is not hidden from anyone, but unfortunately, it has not been found in a suitable solution. Many countries use different methods to prevent the damages of climate change in the future. It is clear that disturbing the order of nature disturbs the balance. Further research similar to the present research can tell the past climate in more detail.

Old landslides can be effective in the formation or occurrence of landslides. The purpose of this research is to investigate the old landslides before the landslide caused by the Richter 7.3 earthquake in 2016 in the northwestern region of Sarpol-Zahab (Melleh Kabud).In this research, geomorphological and geological evidences such as the geometric shape and topography of the earth, the movement of marl layers on Quaternary alluvial sediments, sedimentology and the analysis of geological layers and the effects of rock dissolution have been used.In the upper parts of this unevenness, the slope is less with a cover of fine-grained clay sediments, and in the lower parts of the slope, it is more composed of particles and coarse-grained stones. The displacement of the lower layers of marl on the surface layers of alluvium and the tilting of the effects of dissolution of rocks are other evidences of the occurrence of old landslides.The lapias, which should be perpendicular to the surface and in the direction of the greatest slope, are located in different directions, which all indicate the occurrence of old landslides in the investigated area.

Quaternary volcanic activity, as the last magmatic effort in Iran, is the evolution of large volcanic cones such as Damavand, Sahand, Sablan, Taftan and Bazman, as well as lava flows such as Mako basalts and Lot block. Sablan, a young member of the Cenozoic volcanic complex, belongs to the Alborz magmatic arc (AMA). In Sablan Mountain, there is a collection of volcanic rocks with the composition of andesite, basaltic andesite, dacite, rhyodacite and trachy andesite. The texture of these rocks is mostly porphyritic with microlithic clay, porous porphyritic, sometimes glomeroporphyric, sieve and trachytic. Among the main minerals, plagioclase and one or more mafic minerals such as hornblende and pyroxene can be mentioned. Secondary minerals include opaque minerals, edengsite, chlorite and calcite. In the normalized multi-element diagrams, relative enrichment of K, Ba, Rb and relative depletion of Ti, Ta, and Nb indicate magmatism affected by subduction processes. In terms of the chemical composition of these rocks, the main elements such as K2O, Na2O, MgO, Al2O3, SiO2 Mg# and K2O/Na2O and the composition of rare elements such as Cr, Ni, Yb, Y, Sr, Rb Sr/Y and La/Yb are in the range Adakite stones are placed. In addition, the geochemistry of these rocks, including the concentration of Cr, MgO, Th, Rb, Th/Ce, and K2O/Na2O, is in better agreement with the adakites derived from partial melting of the subducted oceanic sheet. According to the petrographic diagrams, the adakitic magma forming these rocks was formed from the partial melting of an eclogitic source rock or amphibolite garnet resulting from the metamorphism of the subducted Neotethys oceanic plate under Central Iran. Keywords: petrology, PULL PARAT, petrogenesis, Iran.

In this article, the activity of FMP in Pardis region, southeastern part of Central Alborz, has been studied.Some of the most the most important active faults in the study area are Mosha, Telo Paien,Latian, Sorkhe Hessar, Eivanakai, Qasre Firozeh, Kowsar, Niavaran, Qebleh faults. Methods In this study, a theoretical model for evaluating FMP based on the relationship between the geometric properties of the fault and the regional tectonic stress field is proposed. It should be noted that the results of this method are consistent with past seismic records and current micro-seismic activity in the region, so this theoretical model is based on the relationship between the geometric properties of faults and regional tectonic stress field. The main purpose of this study is to evaluate the FMP of the campus area in the northwest of Niknam Deh to the southeast of Chenark. Using structural data, in order to achieve the position of the main stress axes, in a large area of the study area . Results and iscussion: According to FMP calculations in each section, it was determined that Mosha, Latian and Niavaran faults have the highest Movement potential compared to other fault sections. Conclusion The results of calculations in each section show a good agreement with the frequency of earthquakes, so that the eastern part of the region has a higher seismicity rate than other parts and the eastern part of the region (between Mosha fault and Niavaran fault) It will have the highest probability of landslide in the future, while the southern part of Niavaran fault is associated with the highest amount of FMP and the tectonic structures of its areas are introduced as the youngest neotectonic activities in the area.