Quaternary Journal of Iran

Abstract Abstract
The Kani Bel spring in Paveh is a prominent geological feature of the Quaternary Zagros fold belt in Kermanshah, Iran, and is a significant karst water source in this area. This spring has developed in the Dariyan Formation and, to some extent, the shale and limestone layers of the Gadvan Formation. The formation of this karst reservoir is primarily influenced by late mountain-building movements, as well as tectonic forces and numerous major faults in the region with both east-west and northeast-southwest trends. These faults have caused displacement and movement of the limestone layers, speeding up the development of the karst. The faults in this region are slip faults, which have shifted adjacent limestone layers and created conditions for intense erosion and the formation of a karst aquifer. The dissolution and corrosion of carbonate rocks have led to the development of complex karst networks in the Zagros, making it one of the most important water sources in the region.
Introduction
Karsts are among the most important water resources. Approximately 10.5% of Iran's area is comprised of carbonate formations (Hamidi Zadeh et al., 2012). In most of these formations, karst aquifers are present (Karimi Vardanjani, 2015). The water from karst springs often flows out as a spring after passing through various layers of the earth under the influence of complex processes and hydraulic pressure. This emphasizes the necessity of investigating the geological and geomorphological characteristics of springs to understand the internal features of karsts. The factors influencing karst development can be categorized into three groups: 1- Climatic factors such as temperature, carbon dioxide pressure, and precipitation; 2- Geomorphological factors such as topography and drainage systems; and 3- Geological factors like faults, fractures, lithology, etc. (Karimi Vardanjani, 2015). This research aims to examine the geological and geomorphological causes and factors contributing to the formation of the Kani Bel Spring in Paveh, Kermanshah.
Research Methodology
The research is based on library and documentary studies, satellite image analysis, remote sensing, and field surveys. Using maps of the area of interest, the analysis of Landsat 9 satellite images, field surveys, geological features, lithology, geomorphological characteristics of the spring, and tectonic structures of the basin were examined. Additionally, various structures and geological analyses were extracted using remote sensing, employing data from Landsat (Landsat 9), ASTER, and the Advanced Land Observing Satellite (ALOS PALSAR) with a spatial resolution of 12.5 meters.

Discussion
Carbonate formations in Iran cover an area of about 185,000 square kilometers. 23% of this area covers central southern Iran, with a total of 55.2% located in the Zagros basin. The folded Zagros contains two formations capable of karstification, namely the Gadowan and Daryan formations, which date back to the Lower Cretaceous, Aptian, and Albian periods, and serve as karst reservoirs in the Bel spring area in northern Paveh.
Geological surveys reveal that tectonic mechanisms and slip-fault movements, along with tectonic pressures, identify that the recharge of the aquifer occurs continuously due to suitable average precipitation and the purity of the limestones of the Daryan and Gadowan formations, providing a good water reservoir in the area. These tectonic mechanisms involve faults and fractures oriented in two directions: north-south and northwest-southeast.
Results
The Kani Bel spring in Paveh is one of the distinctive geological phenomena of the folded Zagros and is considered a significant karst water source in this region. It is located in northern Paveh, near the Hajij village, the Sirvan River, and the Daryan Dam. This spring, as one of the water reserves in the folded Zagros, has formed under the influence of tectonic mechanisms and slip-fault movements, causing the displacement of limestone layers adjacent to each other, facilitating the development of a severe erosional regime and the evolution of a karst aquifer in both east-west and northeast-southwest directions at various times. The Kani Bel spring has developed under the geological conditions of the Daryan and Gadowan formations and is one of the water-rich areas in the Zagros zone. The erosion and dissolution of carbonate rocks have led to the formation of complex karst networks in the Zagros, contributing to the evolution and development of one of the most important water resources in the Zagros zone. The karstification processes in the folded Zagros have intensified due to limestone formations and high volumes of precipitation. The recharge of the aquifer in this spring and karst formation has continuously occurred throughout different geological periods, resulting in a good water reservoir in the area.
Keywords: Darian Formation, Gadvan Formation, geomorphology, Kani Bell, karst reservoir
References
Hamidi Zadeh, F., Kalantari, MR. & Cherchi, E., 2012. Hydrogeological and geostructural survey of Dareh Anari spring in Shirin Bahar karst area of Khuzestan province. Iran's water resources research, 8 (1), 30-42
Karimi Vardanjani, 2015. Karst hydrogeology and geomorphology (2nd edition, V.1-1). Aram Shiraz Publications

Abstract With the development of the drilling industry in the country since the early 1930 and the use of deep well drilling technology to exploit groundwater resources, the balance of renewable water usage has been disrupted, leading to numerous social conflicts. Since the damages caused by such exploitation become apparent later, its irreversible effects may persist for decades or even centuries. This can result in the migration of residents, abandonment of investments, and ultimately, desertification. Unfortunately, in densely populated provinces of the country, reliance on groundwater resources for water supply has led to land subsidence. Despite favorable climatic, hydrological, and geological conditions, and the abundance of surface water resources, Alborz Province has not been spared this hazard. According to studies conducted by the Geological Survey and Mineral Exploration Organization of Iran since 2005, the plains of this province have been classified as critical. Examination of land subsidence evidence in Alborz plains indicates that the most significant impact of groundwater extraction has been observed in the Hashtgerd plain, primarily due to fine-grained sediments in the central and southern parts of the plain and agricultural land use. The geological conditions of the Karaj plain appear to control this phenomenon, minimizing its damages.
According to the results of remote sensing, only 8% of the area of ​​the Eshtehard plain is involved in subsidence at a rate of 3 cm per year. 92% of the plain does not have this risk. The subsidence center is in the west of Eshtehard plain with an area of ​​22.5 square kilometers. The maximum subsidence rate in the Eshtehard industrial town is estimated to be 8 cm per year as a point, which seems to have occurred due to the exploitation of deep wells and under the influence of the subsidence cone.
The Fissures Observed in the Eshtehard plain since 2005 have been Attributed to land subsidence. Due to the expansion of cracks in the area, urban infrastructures including power transmission towers and electric poles and buildings have been damaged. Over time, these collapses have been affected by water erosion, and the bottom layer, which is made of sand, has been emptied, resulting in the collapse of the roofs of the tunnels, and thus, with the development of these channels, a large area of ​​the plain has been involved in these cracks. .
However, fissures in the Eshtehard plain are attributed to fine-grained and dispersive soils that lack load-bearing capacity. Inappropriate land use, disruption of the region’s hydrological cycle, and the alternation of wet and dry conditions have caused these fissures to manifest as various cracks in the clay soils.
From a sedimentological perspective, the presence of a 3-4 meter layer of fine grain silt and clay deposits is evident in all areas involved in the gap. This clay layer is resistant to the passage of water and has no hydraulic conductivity. At a depth of more than 3 meters, there is a permeable layer of sand, which has created deep tunnels with the passage of subsurface flow and the washing of sand over time. Over time, these fissures, under the influence of water erosion, have evolved into large gullies. Analyzing the subsidence phenomenon in any plain requires a thorough understanding of aquifer geometry, geophysical studies, geology, and hydrogeology. Comprehensive studies and the tectonic conditions of the Eshtehard plain indicate the presence of two distinct sedimentary environments in the plain. In the eastern part of Eshtehard, a shallow surface aquifer exists, and due to low water quality and minimal exploitation, subsidence is not an issue. However, the western part of Eshtehard forms a deep sedimentary basin, containing fine-grained clay and silt interlayers up to a depth of approximately 70 meters. In this aquifer, excessive exploitation since 1986 has led to a 40-meter decline in groundwater levels. Near the Eshtehard industrial park, this change in water levels has reversed the hydraulic gradient and disrupted the balance of the groundwater table. Consequently, subsidence has occurred in the deep western aquifer, necessitating measures to control exploitation. However, surface fissures observed 7 kilometers west of the Eshtehard aquifer are not the result of horizontal ground movements due to subsidence. Soil mechanics studies confirm that these fissures are due to the soil and sedimentary characteristics of the region, exacerbated by climatic events and intensified over time by improper land use and loading.

Abstract Abstract
Leveraging the significant presence of Alpine folds in Isfahan Province, which, in conjunction with karstic and tectonic activities, have resulted in the formation of numerous caves, this study undertook a comparative analysis of six large and relatively well-known karstic-tectonic caves (Khaseh-Trash, Pariyan, Shah-Qandab, Yeke-Chah, Kalahhroud, and Sangriz) with the aim of ranking and selecting them for geotourism development planning. Initially, after outlining the components, the tourism value of the caves was determined and evaluated by experts using the Pralong method. This assessment was based on structural, geoheritage, economic, and exploitative features through the completion of questionnaires. Furthermore, the identification of geomorphosites involved collecting information about geological, geomorphological, and other pertinent characteristics through field surveys and literature reviews. Each geomorphosite was graded for each of the mentioned values, with a ranking scale ranging from 0 to 1. In total, the average score for each cave was 0.70 per value, varying between 0.4 and 1. Furthermore, the average final (tourism) value for each cave was 0.73, with values ranging from 0.60 for Sangriz Cave to 0.98 for Kalahroud Cave. The comparison of various tourism values indicates the prioritization of tourism development in the following order: Kalahoroud, Yekeh-Chah, Khasseh-Tarash, Pariyan, Shah-Ghandab, and Sangriz Cave geomorphosites, based on their respective levels of significance. Accordingly, the deployment of geotourism programs, alongside continuous management and monitoring, fosters the efficient allocation of investments and market opportunities. Moreover, it has been proven once more that the application of this research can aid evidence-based decision-making regarding the management and conservation of geomorphosites.
Extended Abstract
1. Introduction
As a subset of tourism, geotourism emphasizes the exploration of geological and natural features in diverse regions. This approach to tourism not only fosters economic development but also aids in environmental protection and increases public consciousness. Precise evaluation of geosites is vital for the sustainable advancement of geotourism. This process helps to uncover the tourism potential of various regions, ensures appropriate planning for tourism expansion, and supports the conservation of natural resources. A thorough and comprehensive assessment of geomorphosite potential is essential for sustainable tourism development. A comprehensive assessment of geomorphosites for tourism purposes involves multiple methods, such as professional evaluations, visitor surveys, and detailed analyses of the site's geological and ecological attributes, which often require a combination of field studies, geological and topographic mapping, and advanced scientific techniques. With its high karst potential and diverse cave systems, Iran possesses significant geotourism potential. Isfahan Province, in particular, given its remarkable caves, necessitates comprehensive geotourism development plans to identify, classify, and assess these potentials. By applying the Pralong method, this research aims to identify and prioritize karst geosites for sustainable geotourism development.
2. Material and Methods
To assess the geotourism potential of the studied caves, the modified seven-item Pralong (2005) form was used to evaluate the five-index matrix of cultural, economic, usability, scientific, and aesthetic values. This model examines the tourism potential of a geomorphological landform from four perspectives: aesthetics, science, cultural-historical, and socio-economic. The method specifies particular criteria for determining the value of each aspect of the geomorphological landform's tourism potential. Each of these values was determined for the six studied caves, and then by assigning scores to each factor, the total score of each cave was calculated. Subsequently, a comparison of scores between the caves was conducted, and finally, the overall value of the landforms was determined.
3. Results and Discussion
When comparing the scenic value of the caves, the Pariyan and Kalahroud Caves were found to have the highest scores due to their superior visibility, viewing angles, and contrast in color and vertical development of the landforms, while Sangriz Cave scored the lowest. The scientific value of the caves is linked to their rarity, educational appeal, and ecological significance. Kalahroud and Pariyan Caves excel in these aspects, while Sangriz and Shah-Qandab Caves rank the lowest. The cultural value of these caves is assessed based on their religious, historical, artistic, and literary significance. When ranked, the Yekeh Chah, Kalahrood, and Khasseh Tarash caves emerged as the most culturally valuable, while the Shah Qandab and Sangriz caves were rated the lowest. The socio-economic value refers to the potential of using caves for tourism or sports. The Kalahroud, Pariyan, and Yekechah caves have scored full marks in this regard, indicating their multiple values. The utilization value encompasses the degree and manner of cave exploitation. In this section, conservation measures have the highest score, while visitor numbers and accessibility are the weakest indicators. The Yekechah and Sangriz caves exhibit a better status. When considering a broad range of criteria, the Kalahrud, Pariyan, and Yekechah caves demonstrate superior qualities and significant potential for tourism development.
4. Conclusion
A comparative assessment of several karst caves in Isfahan Province based on their geotourism potential, utilizing a modified Pralong method, revealed that the Kalahroud, Yekechah, and Khasseh-Trash caves demonstrate the highest potential for tourism development. These caves have achieved nearly or exceeded 90% of the required tourism value. Although this does not negate the tourism potential of other cave geomorphosites, it suggests that they should be prioritized for development in subsequent phases. This finding aligns with the existing international recognition of these specific locations. Moreover, a systematic theoretical framework now supports this prioritization. It is noteworthy that while the studied caves possess high socioeconomic value, their current utilization rate is relatively low. Only the Sangriz and Shah-Qandab caves exhibit a higher utilization rate stemming from their cultural and historical significance.

Abstract Introduction
As one of the most seismic regions in the world, Iran has two main tectonic belts (Berberian and King, 1981). The Zagros belt, which starts from the eastern end of the Makran subduction zone in the Oman Sea. The trend of this belt is southeast-northwest and its other side is limited to the eastern corner of the North Anatolian fault (Nissen et al., 2019). The Alborz tectonic belt starts from this point with an east-west trend and extends to the Kepe Dagh fault in the northeast corner of Iran (Alavi, 1996). The central part of the Alborz belt is surrounded by active faults that have caused the destruction of cities in the region in the past centuries (Zanchi et al., 2007). Investigating the activity of these faults and how they function during a major earthquake event is very important (Berberian and Yeats, 2016). On the other hand, the effect of the construction in the dispersion of the waves of such earthquakes can significantly affect the destruction of the structures (Habibi et al., 2023). On average, from 1900 to 2014, 3 people died every hour in Iran due to earthquakes (Berberian, 2014). Such a shocking statistic makes it even clearer that it is necessary to pay more attention to the conditions of the building.

Materials and Methods
Systematic records of earthquakes that occurred in Karaj and its surrounding areas have been prepared from the catalog of various international sources and published studies. Sources of earthquake records include the International Seismological Center (ISC) comprehensive catalog from 1908 to 2023, the Global Earthquake Model (GEM) catalog from 1903 to 2019, and historical earthquake records from published studies (Ambraseys and Melville, 1982; Berberian, 1995; Berberian et al. ., 1983, 1985) was collected for an area with a radius of 150 km from Karaj. It was tried to add the relevant earthquakes to the catalog in cases where the length of active faults in the region is outside this radius. Seismic records are collected, reformatted, and stored chronologically to produce a uniform composite seismic catalog.
The catalog of clustered earthquakes for the period 1762 to 2023 is not complete. Seismic rates predicted using the earthquake events in this list may underestimate the occurrence of future earthquakes in these regions. A reliable mean seismic rate can be predicted by identifying the period over which the catalog is complete for a given magnitude range. Therefore, completeness periods for different magnitude ranges are determined using the Step method (Stepp, 1972).
Results and Discussion
In addition, during the return periods of 475 and 975 years, the values of earthquake acceleration from the PGA period have an increasing trend until 0.2 seconds and then decrease. But in the return period of 2475 years, the upward trend is observed even up to a period of 0.3 seconds.
In order to control and check this point, it is necessary to use earthquake risk separation charts. The relative contribution of seismic sources (isolation model) in seismic hazard (PGA) and period of 0.3 s for three return periods of 475,974,2475 years for the central point of Karaj city are shown in Figures 6 and 7. Also, the numerical values obtained from these graphs are presented in Table 4. The percentage values of the contribution of each of the seismic sources in the total risk are displayed as a pie chart. In all the analyzes of Table 4, the share of faults in the total risk is North of Karaj, North of Tehran, Mosha, Taleghan, Peshva, and Firouzkuh, respectively. But clearly, in the return period of 2475 years in a period of 0.3 seconds, the contribution of seismicity of North Tehran fault increases compared to other faults. These diagrams show the role of distant springs in the changes of spectral acceleration values. In this way, the effect of the faults that are far away can be clearly seen in increasing the acceleration of the earthquake for long return periods and long periods.

Conclusions
The most challenging part of seismic hazard analysis is identifying seismic sources. The most important limitation for the description of seismic sources is the uncertainty in determining the location, geometry, size of the earthquake and the open distance of the occurrence of each source. Large earthquakes (Mw > 7) occur at intervals of hundreds to thousands of years. But the historical records of earthquakes in these areas go back to 1830 AD Masha fault. The proper identification of the epicenter of the earthquake was not possible until the beginning of the 20th century, when the recording of earthquakes began. Therefore, the foci of historical earthquakes were identified based on the severity of damage to the structures. The rupture of smaller and deeper earthquakes does not appear on the surface of the earth. Large, shallow crustal earthquakes generally cause surface ruptures, but due to the lack of understanding of the earthquake mechanism, the ruptures of those earthquakes are not well documented. Fault slip in prehistoric and historic earthquakes can be estimated through paleoseismological studies. Therefore, in this study, while examining recent paleoseismological studies, the geomorphic evidence of past earthquakes was determined. Also, the statistics of historical and prehistoric earthquakes in all the faults of the region were accurately identified. Then, the Probabilistic Seismic Hazard Analysis (PSHA) has been performed using recently published data and information. A shallow crustal fault model has been used to estimate seismic hazard using the recently published Ground Motion Prediction Equations (GMPEs). Epistemic uncertainties have been calculated using the logical tree approach. The value of spectral acceleration was estimated for the return period of 475, 975, 2475 years in PGA periods of 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.75 and 1.0 seconds. In these calculations, the shear wave velocity map of the region has been used for the first time.

Abstract 1-Introduction
Desert areas face many changes due to their sensitive ecosystems and morphology. Changes in desert areas are affected by various natural and human factors, including hydroclimatic factors, wind speed and direction in the region, destruction or creation of vegetation cover, etc. Among the forms of desert areas that face many changes and in many cases cause hazards and crises are sand dunes or sandbars. In fact, sandbars in desert areas consist of a set of sand dunes that have diverse morphology and active dynamics. In addition to the positive potential they have in the field of tourism development, etc., sandbars are also associated with many environmental consequences and problems. Given that most sandbars are dynamically active, the sand dunes in sandbars have a significant advance towards agricultural lands and infrastructure every year and can directly cause the destruction of these uses. Also, in many cases, sand dunes are considered dust centers and, depending on the speed and direction of the winds in the region, they can cause dust storms and thus create crises for different regions. Considering the importance of the issue and also because no comprehensive studies have been conducted regarding sand dunes located in the southern regions of the Alborz highlands and the Kavir plain, this research has examined the morphological and dynamic status of the sand dunes in this region.

2-Materials and methods
This research is based on remote sensing and statistical data, and descriptive-analytical methods have been used to analyze and interpret the information. In this research, various data, including statistical information related to wind speed and direction of 12 meteorological stations and satellite images (Google Earth and Landsat 8), have been used as the most important research data. Also, Google Earth software (to draw the exact area of sand dunes and monitor their movement), ArcGIS (to prepare the desired maps), and WRplot (to analyze the wind speed and direction of the region) have been the most important research tools. Considering the subject and objectives, this research has been carried out in several stages. In the first stage, using Google Earth images, the exact area of sand dunes of the Kavir plain and southern Alborz has been drawn, and then its morphometric status has been examined. In the second stage, according to the shape of the sand dunes, the sand dunes of the Kavir plain and southern Alborz are divided into different classes. In the third stage, using 203 sample points and Google Earth images, the amount of sand dune movement in the region during the years 2005 to 2020 was evaluated. In the fourth stage, based on the information of the studied meteorological stations, the wind speed and direction of the region were evaluated.

3-Discussion and Results
The results of this study have shown that a large part of the desert areas of the southern Alborz regions and the Kavir plain are covered by sand dunes, so that the total area of sand dunes in this region is about 13,081 square kilometers. Among the sand dunes of the southern Alborz regions and the Kavir plain, the Jen, Shotori, and Kashan-Ardestan sand dunes have the largest areas with an area of 4,744, 2,823, and 2,134 square kilometers, respectively. Given that the sand dunes of this region are very diverse in terms of wind speed and direction, as well as topographic conditions, they are also very diverse in terms of appearance. In this study, the sand dunes of the region have been divided into 10 classes. Based on the results obtained, the thin sand cover, complex transverse sand dunes, and complex sand dunes have the largest area with an area of 2944, 2876, and 2447 square kilometers, respectively. Also, based on the results obtained, about 78 percent of the sand dunes in the region are active, so that the displacement of the sand dunes of this region during the years 2005 to 2020 was between 5 and 65 meters, and in general, the highest displacement was related to the southern areas of Shotori erg. In this study, the wind speed and direction of the region and its relationship with the shape and movement of the sand dunes of the region were also evaluated. Based on the results, the highest wind speed was in the southern areas of Jen and Kashan ergs.

4-Conclusion
The results of this study have shown that there was no significant relationship between the morphological and dynamic state of the sand dunes in the region and the speed and direction of the winds in the region. According to the results, in some areas, such as the northern areas of Kashan erg, there was no correspondence between the wind speed and the amount of sand dune movement, the main reason for which was the morphological and vegetation status. Considering the above-mentioned cases, the morphological and dynamic state of the sand dunes in the studied area was affected by the wind speed and direction, vegetation, and the geomorphological status of the area. The overall results of this study have shown that the sand dunes in the region have a great diversity in terms of morphology, which can be used for various purposes, including tourism development. They are also dynamically active, and given that some of them, including the Kashan-Ardestan erg, are near populated areas, they can cause destruction of agricultural lands and other man-made uses, so it is necessary to take necessary measures, including stabilizing them using vegetation cover

Abstract Abstract
This study investigates the base-level changes and geomorphological evolution of the Sefidrud drainage basin and its sub-basins, including Tarom, Zanjanrud, Mahneshan, and Bijar. The analysis of mechanisms transforming endorheic basins into exorheic systems reveals that factors such as head ward erosion, overspill, and tectonic activities play a fundamental role in shaping landforms and sedimentation patterns. Fluctuations in the Caspian Sea's base level, as a key factor, have caused significant erosion and river diversions. These phenomena, alongside local tectonic activities and climatic changes, have led to the formation of diverse landforms such as alluvial terraces, waterfalls, hoodoos, and badlands. The results demonstrate that head ward erosion and tensile forces were pivotal in shaping current landforms. Additionally, Quaternary climatic variations and base-level oscillations significantly influenced the basin's evolution. Further detailed studies on geomorphology and geology are essential for a comprehensive understanding of these processes.

Introduction
The Sefidrud drainage basin, located in the Alborz mountain range of northern Iran, has undergone significant geomorphological transformations due to tectonic activities and fluctuations in the Caspian Sea's base level. These changes have shaped diverse landforms and altered hydrological patterns. This paper aims to analyze the mechanisms driving the transformation of the Qezel-Ozan-Shahroud basin from an endorheic to an exorheic system, focusing on the interplay between tectonics, climate, and base-level changes.
The study area is divided into two zones:
1. Hydrological Basin: Defined by natural units, this includes sub-basins such as Shahroud, Taleqan, Tarom, Zanjanrud, Sohrain, Shorgol, Mahneshan, and Bijar.
2. Geomorphological Basin: A broader area encompassing adjacent basins (e.g., Urmia and Mesileh-Qom) to analyze surface levels and geomorphological phenomena.
The Tarom basin, located between 36.5°–37.5° N latitude and 48.5°–49.75° E longitude, is separated from the Talesh mountain range by the Tarom Mountains. Its elevation ranges from less than 250 m above sea level at the valley floor to over 2,800 m at surrounding peaks.
Materials and Methods
This research integrates field observations, GIS analyses, and geological data to provide a comprehensive understanding of base-level changes and their impacts on geomorphological processes. Data collection methods include:
1. Field Data:
• Identification and documentation of geomorphological landforms (e.g., hoodoos, badlands, waterfalls, alluvial terraces).
• Analysis of topographical changes along rivers to assess base-level fluctuations.
• Repeated field visits to evaluate long-term changes.
2. Documentary and Map Data:
• Digitization of lithological layers from 1:100,000 geological maps provided by the Geological Survey of Iran.
• Extraction of a 30×30 m DEM from the SRTM satellite via Earth Explorer to generate contour lines (10 m intervals) and drainage networks.
3. Scientific Literature Review:
• Examination of studies on the transformation of endorheic to exorheic basins (e.g., Douglas et al., 2009; Ballato et al., 2017).
4. Results and Discussion
Mechanisms of Basin Transformation: Four primary mechanisms drive the transformation of endorheic basins into exorheic systems:
1. Antecedent sedimentation.
2. Head ward erosion.
3. Overspill.
4. Tectonic valleys formed by tensile forces.
These mechanisms significantly alter hydrological patterns and geological structures. For instance, head ward erosion in the Tarom basin has led to the capture of drainage networks and the formation of deep canyons. Similarly, tectonic activities have divided the Zanjanrud basin into several tectonic blocks, with the Sultanieh fault creating subsidence zones.
Geomorphological Landforms: Fluctuations in the Caspian Sea's base level have resulted in diverse landforms, including:
• Alluvial terraces.
• Waterfalls.
• Hoodoos and badlands.
• Deep, narrow canyons.
In western Qezel-Ozan, unique "Martian-like" mounds have formed due to contrasting geological layer dips and lithological compositions of marls and sandstones.
Impact of Base-Level Changes: Base-level fluctuations have profoundly influenced geomorphological processes. For example, the diversion of the Ghal-e-Chay River has led to the formation of Lake Pari, which was later drained due to base-level lowering. Geomorphological evidence, such as slope gradients, sediment types, and channel morphology, supports these interpretations.
Role of Tectonics and Climate: Tectonic activities and climatic changes have played complementary roles in shaping the landscape. In the Mahneshan basin, large-scale structural changes have reoriented drainage patterns from NW-SE to nearly E-W. Similarly, Quaternary climatic oscillations during glacial and interglacial periods have caused significant variations in runoff and sedimentation.
Conclusion
The Sefidrud drainage basin has undergone profound geomorphological and hydrological transformations due to base-level changes, tectonic activities, and climatic variations. These processes have not only shaped unique landforms but also altered sedimentation patterns and drainage networks. This study highlights the importance of integrating field observations, GIS analyses, and scientific literature to understand complex geomorphological systems. Further research is needed to explore these dynamics in greater detail.
Keywords: Base-level changes, Head ward erosion, Tectonic activities, Alluvial terraces, Geomorphological landforms

Abstract 1. Hamed Alianpour, Department of Applied Geology, Faculty of Earth Sciences, Kharazmi University, Tehran, Iran.
2. Saeid Asiabar, Azad university
3. Maryam Dehbozorgi, Professor of Geologyy, Faculty of Geology, Kharazmi University, Tehran, Iran
4. Reza Nozaem, Professor of Department of Geology, University of Tehran. Iran
5. Nasim Ramezani, Faculty of Geology, Kharazmi University, Tehran, Iran
1-Introduction
Determining the anomalies resulting from active tectonics in rivers using geomorphological indices is very useful and can be associated with revealing active structures in the region. The evaluation of structures and landforms throughout their history of occurrence is the main subject of tectonic geomorphology (Shum et al., 2002, 276). The study of active tectonics is of great importance in assessing geological hazards, which is doubly important in areas with intense tectonic activities in the Holocene and Pleistocene (Ramazan et al., 1402)
2-Materials and methods
In this study, using Arc GIS software and a digital elevation model of 30 meters using the Strahler method, watersheds were divided and extracted. Then, by using topographic maps on a scale of 1:25000 and geological maps on a scale of 1:100000 and aerial photos on a scale of 1:20000 and through the Arc GIS software, different application layers including waterways, basins, faults, lithology and lines height, was prepared and finally, in order to carry out the present research in the area of Western Alborz and Azerbaijan, the studied area was divided into 50 basins and the value of the normal slope index was calculated for all parts of the main and secondary waterways and divided into 5 categories, then with Drawing the longitudinal profile of the longest river of each basin in MATLAB software, the numerical value of this index and the concavity index were calculated separately for each basin. Also, the Knickpoint extraction of a fault was carried out due to the sudden changes in the slope of the river in collision with the main faults, in order to investigate the tectonic activity of the region. Finally, the geological units and main structures of the region were examined and analyzed with the results of the longitudinal profile of the river and field observations.
3-Results and discussion
The results of quantitative investigation of changes in the longitudinal profile of the river and extraction of river channels in 54 drainage basins indicate high tectonic activity in the central and northern parts of the study area in the Bisotun-Taqebistan, Sahneh and Mianrahan faults. The normal slope index (Ksn) and concavity () calculated using the longitudinal profile and in the MATLAB software; indicate that the high values ​​of these indices show good agreement with the known faults of the study area. Using the values ​​of the normal slope index in the entire study area, the Ksn map of the region was prepared using the IDW interpolation method for the entire region. According to this map, the southern parts of the region, including the areas around the Bisotun-Taqebistan, Menghlat and Peru faults, show almost the highest value of this index. Also, the southern branches of the Mizanrahan and Qeshlaq faults have high values ​​of this index. The areas between the Sahneh and Mizanrahan faults, the areas between the Morvarid and Qeshlaq faults, and the southwestern parts of the region have the lowest values ​​of this index. In this study, the river breaks in the study area were extracted using a new method and then separated from each other according to the factors affecting their formation. In this method, the river breaks located in the longest river of each basin were extracted using the longitudinal profile obtained from the digital elevation model of each basin in the MATLAB software (Kirby et al., 2007). The data are processed and modified by the software and then the river breaks are extracted using the longitudinal profile of the river. Also, unlike the old methods, the river breaks of rivers with a length of less than 10 km can be extracted. A high percentage of the extracted river breaks are related to faults in the study area, which can indicate the possible effect of faults on changing the slope of the riverbed and their recent activity. In the southernmost part of the study area, several river breaks have been created by the action of the Kooh-e-Safid, Shirazi, and Sarab faults. The presence of numerous river breaks in the basin of the Bisotun-Sahneh thrust at the intersection of the fault with the river indicates the possible recent activity of these faults. Numerous river breaks in the central parts of the Bisotun-Sahneh thrust, near the village of Chalabeh, as well as the increase in the normal slope index of the river in contact with the fault in this area indicate the greater activity of this part of the fault .
4- Conclusion, Keywords
- Current very high and high tectonic activity in the Bisotun-Taghbostan thrust zone and the Sahneh-Morvarid fault zone as part of the Zagros Main Fault (MRF) and moderate and relatively high activity in the Mianrahan fault and the Kooh-Safid fault zone as a branch of the Zagros Thrust Fault (ZTF) in the study area based on the results of quantitative analysis of the longitudinal profile of the river and the extraction of the river break.
- Acceptable correspondence of the occurrence of earthquakes with the level of tectonic activity based on changes in the longitudinal profile of the river as initial studies to identify seismically active areas and long-term earthquake forecasting in areas with high tectonic activity.
The visited Raba and finally the tectonic activity of the area were analyzed and evaluated.
Keywords: Active tectonics,longitudinal profile of the river,Rudshekan,Sanandaj-Sirjan,Active tectonics

Abstract Introduction
Sabalan Volcano is located 40 km west-southwest of Ardabil city and 25 km southeast of Meshginshahr (Iran). This mountain is mainly located in Ardabil province, with some areas in the southwest of East Azerbaijan Province. According to recent structural studies of fractures and fault trends in Sabalan Mountain, strike-slip faults have led to the creation of extensional spaces and pull-apart basins in the region (Abdollahadi et al., 2024). During the Quaternary Period, the basic magmas of the region reached the surface along these extensional spaces. These magmas have been slightly contaminated with the lithospheric crust and have largely retained the characteristics of their asthenosphere origin. Afterward, the lithospheric crust has been delaminated, partially separated from the crust, and immersed in the asthenosphere. In the meantime, partial melting of this crust has caused the formation of volcanic rocks in Sabalan.
Study Method
About 100 samples were gathered from the study area to identify the texture of the rocks and their mineralogical composition. Next, 80 thin-section samples of volcanic rocks were prepared from them and studied with a polarizing microscope. The thermobarometric studies were conducted on the basalts and andesites of the studied area by preparing 5 thin-polished sections. Point analysis of minerals was performed using an electron microprobe analysis device, employing the XPMA method, in the Binaloud deposits. To this end, a HORIBA microscope (model: XGT-7200) with an accelerating voltage of 50KV and a current intensity of 1 mA was used. The point analysis device had a diameter of 10 μm and a duration of 80 s for each point.
Results
The Quaternary basic volcanic rocks of the region include trachyandesite, andesite, and trachydacite, which account for a significant volume of magma in the region. These rocks show a variety of porphyritic, flow, glomeroporphyritic, and sieve textures. The principal minerals of these rocks include plagioclase and one or more mafic minerals such as hornblende and pyroxene. Sieve texture is among the most important unequigranular textures in plagioclase crystals of Quaternary volcanic rocks. Zoning and degraded surfaces are observed at the margins of some plagioclase crystals of the rocks of the region. The plagioclase minerals of the igneous rocks of the region have a chemical composition range of labradorite to bitonite. Based on thermo-barometric calculations, plagioclase crystals of andesitic rocks (PL1) crystallized in the pressure range of 6 to 8.5 kbar and temperature of 1035 to 1,045℃; plagioclase of trachyandesitic rocks (PL2) crystallized in the pressure range of 5.5 to 7 kbar and temperature of 1035 to 1055℃; plagioclase of dacite rocks (PL3) crystallized in the pressure range of 5.5 to 8 kbar and temperature of 1035 to 1045℃; and plagioclase of rhyodacite rocks (PL4) crystallized in the pressure range of 6 to 8 kbar and temperature of 1035 to 1055℃.
From textural observations, a simple magma chamber model for the study area can be imagined based on the model proposed by Ranjit (2014). Based on this model, in the initial stage, the high-temperature water-saturated magma underwent extensive crystallization in the stable magmatic environment of the deep chamber, producing An-rich plagioclase. As this crystal-rich magma ascended to the shallow chamber, these crystals were subjected to different dissolution rates, leading to the development of coarse sieve (CS) texture with different sizes, shapes, and densities (number of CS per unit area). The variation in dissolution intensity can be attributed to differences in the decompression rate or the content of dissolved H₂O in the magma (Viccaro et al., 2014). Immediately after dissolution, many crystals may coalesce into glomerocrysts and later re-grow as single grains, while the remaining crystals grow as sheaths on CS nuclei. The crystals produced after decompression are devoid of CS morphology and form small to medium-sized phenocrysts (low An content) in the lava unit. The shallow chamber has been dynamically active by convection or the influx of some new magma, or a combination of both. These activities have limited the growth of pre-existing crystals and new crystals by non-uniform temperature increase and convection processes. They have developed fine sieve (FS) texture, fine oscillatory zones (FOZ), resorption (RS) surfaces, and flotation. The frequent occurrence of FS texture suggests the crystallization of individual grains because of multiple superheats. Therefore, evidence such as FS texture, FOZ, and flotation suggests that the crystals in the shallow chamber have undergone repeated dissolution-regrowth processes in an evolved magmatic environment. During the self-mixing process, the magma chamber may have undergone extreme cooling by degassing or water release and then intense air eruption that produced microlites, broken crystals, and swallowtails.
Conclusion
The Quaternary basic volcanic rocks of the Sabalan Volcano include trachyandesitic, andesite, and trachydacite. The main minerals of these rocks are plagioclase and one or more mafic minerals such as hornblende and pyroxene. Sieve, glomeroporphyritic, and regular textures are among the textures found in the plagioclase rocks of the studied region. The study and interpretation of these textures provide information about the effect of magmatic processes on the crystallization from the magma chamber to the magma eruption. The textures in the plagioclase rocks of the region are of the CS type, characterized by irregular, discrete, and sometimes zoned features, which are related to crystal growth. In this respect, glomerocrysts and microlites are also formed during dynamic magma processes such as convection currents, degassing, or explosive eruption, and in the final stage during or before the eruption of magma. The CS texture is formed more in the andesitic rocks of the region as a result of reduced pressure, temperature, and variations in the composition of the magma. Meanwhile, in the intermediate rocks of the region, the FS texture is common, which is due to the mixing of magma (the entry of calcium-rich basic magma into the intermediate magma chamber).

Abstract Introduction:
This study investigates paleoenvironmental changes and sediment dynamics in the Kaji Namakzar Playa, a rhomboidal pull-apart basin north of Nehbandan, eastern Iran. The main goal is to reconstruct late Holocene hydroclimate by integrating geomorphology, sedimentology, and stratigraphic analysis of three undisturbed sediment cores (average depth about 8 meters; maximum about 8.8 meters).
Method:
Fieldwork yielded intact cores that were logged for texture, clay coatings, color, fossil content, evaporite minerals, and sediment consolidation, with photographic records and stratigraphic columns. Core sampling was designed to capture the maximum possible thickness of playa-bed sediments, ensuring representative sampling across homogeneous units. Grain-size analyses used a combination of wet sieving (Analysette 3, Fritsch, Germany) and laser diffraction for particles finer than 63 microns. About half of the samples were processed at Iran’s Geological Survey and Mineral Exploration Organization; the rest were archived. This meticulous sampling and analysis enabled a high-resolution reconstruction of depositional environments within the playa over roughly 13,000 years.
Result:
Seven sedimentary facies were identified across the cores, corresponding to three broad depositional environments: lacustrine, playa, and alluvial-fan (floodplain) settings. The facies show a dynamic interplay among evaporative playa conditions, episodic lacustrine phases, and influx from adjacent alluvial fans. The stratigraphic record spans late Pleistocene through Holocene, with the deepest sections capturing a ~13,000-year window.
Regional syntheses indicate coherent Holocene lake-level fluctuations across Iran, with multiple dry phases and humid intervals. At Maharloo, a notable dry phase occurred between 4300 and 5250 cal BP (about 950 years), with additional less-documented dry intervals around 1800 and 2000 cal BP. Zarivar records warmer phases at about 21,000, 12,600–15,400, ~12,000, and ~11,700 cal BP, while diatom assemblages point to salinity increases at several intervals (17,500–17,700, 12,000–12,600, 5,900–6,400, and ~2,500 cal BP). Dry periods are also reported at 7,500–7,800 and 3,800–4,500 cal BP, with more ambiguous evidence in places. Mi’arabad’s Holocene climate shows dry spells around 5,400 cal BP and ~1,500 cal BP. In Urmia, a major dry episode is dated to ~13,000 years ago, with Heshtilan, Zarivar, Gahar, Abazlo, and Meharlu lakes showing lag or lead relationships in the timing of dry/wet phases.
Within Kaji Namakzar, the stratigraphy reveals pronounced lateral and vertical variability linked to proximity to climate-influenced zones. Core 1 exhibits peat-marsh deposits, indicating a comparatively wetter interval and greater facies diversity than the other cores. From depths of 860 to 600 cm (roughly 15–22 ka), silty and sandy sediments with organic matter dominate, suggesting favorable climatic conditions preceding the Last Glacial Termination. This interval terminates with the Older Dryas, a period of cooling in the Northern Hemisphere. Cores 2 and 3 show more consistent playa or distal-deltaic conditions in western and eastern sectors, respectively, with brownish facies and secondary gypsum in core 3 reflecting arid, low-energy depositional environments.
Discussion and Conclusion:
The Holocene onset brought warmer temperatures (estimates up to ~10°C) that promoted deposition of playa, alluvial, and fluvial sediments and inland progression toward the center of the Namakzar playa. After the Younger Dryas (~11,600–12,800 cal BP), playa sediments initially expanded along the shoreline toward the lake, followed by westward fluvial inputs that reworked older playa deposits and transported some nodular brown clays toward the southern basin (depth ~500–450 cm). Between 295 and 460 cm in Core 1, brown-green clays with nodules imply a cool, dry period around 10–5.7 ka, a phase that likely coincides with the global 8.2 ka event and regional manifestations in the Near East and North Atlantic. In Core 2 (western) and Core 3 (eastern), deposition reflects continued arid-to-semi-arid conditions with less hydrological input and more distal deposition, consistent with reduced lake extent and stronger aeolian influence.
From roughly 40 to 120 cm depth (1–3 kyr BP), a relatively stable and arid-to-cool playa environment prevailed, aligning with the Cohen (2003) model linking Holocene lake-level shifts in North Africa and South Asia. The near-surface interval (40 cm to present) records gradual facies changes with the appearance of silty sediments containing patches of organic matter and plant remains, and the presence of grayish-red sediments indicating low-pluvial, shallow-water conditions.
Overall, the Namakzar playa sequence documents a Holocene record in which arid episodes tend to begin abruptly and end gradually, whereas humid periods tend to terminate more gradually, producing a sawtooth-like climate pattern typical of late Quaternary fluctuations. In a basin where influx from the western alluvial fans (brown sediments) and eastern margins (brown with clay) interplays, the preserved record records both rapid dry onsets and comparatively longer wetter intervals. The seven identified facies—comprising varied clay, silt, and sand combinations with plant and organic matter—record lacustrine, playa, and alluvial-fan environments, highlighting the dynamic interplay among hydrologic regimes, sediment supply, and wind-driven processes.
The Kaji Namakzar Playa thus provides a long, high-resolution archive of Holocene hydroclimate in eastern Iran. Its 13,000-year record reveals three sustained humid periods, multiple arid episodes, and several short-lived or seasonal fluctuations, consistent with the broader late Quaternary sawtooth climate signal driven by global climate oscillations. The study’s integration of detailed sedimentology, facies analysis, and grain-size measurements yields a robust framework for regional paleoclimate reconstructions and offers a valuable reference for comparative studies with other Iranian playas and arid-region basins. The findings underscore the value of playa sediments as archives of regional paleoenvironments and as tests for broader climatic hypotheses in Iran and adjacent arid environments.

Abstract 1-Introduction
Spectral acceleration zoning is a critical tool for evaluating structural response to seismic events and plays a key role in both seismic design and regional risk mitigation strategies.
Tehran, located on the southern flank of the Central Alborz range, lies in one of the most seismically active areas of the Middle East, shaped by the convergence of the Arabian and Eurasian plates. Major active faults such as the North Tehran and Mosha faults dominate the tectonic framework.
However, recent Quaternary tectonic and morphotectonic studies have questioned the seismogenic nature of previously identified faults like North Rey, South Rey, Kahrizak, and Eshtehard, suggesting they may instead represent relict paleoshorelines of the ancient Lake Ray (PAMELA), rather than active tectonic sources (Berberian, 2014; Berberian & Yeats, 2016a; Jarahi, 2021a; Navar Noveiri, 2021; Navar Noveiri et al., 2021; Nazari et al., 2010). This study aims to improve Tehran's seismic hazard models by removing non-tectonic features and integrating reliable paleoseismic data. It focuses on refining ground acceleration estimates and comparing them with previous models, including Standard 2800, EMME, and GSHAP.
Materials and methods
This study presents a comprehensive Probabilistic Seismic Hazard Assessment (PSHA) for the Tehran metropolitan area, based on a revised seismotectonic model that excludes faults lacking credible geomorphological and sedimentological evidence of tectonic activity. The methodology includes four core steps: (1) definition of seismogenic sources, (2) selection of regionally calibrated Ground Motion Prediction Equations (GMPEs), (3) development of a logic-tree to address epistemic uncertainties, and (4) computation of ground-motion exceedance rates. The seismotectonic framework was developed using prehistoric, historical, and instrumental earthquake data from IRSC, IIEES, and ISC Bulletin. Faults such as Eshtehard, North/South Rey, and Kahrizak were excluded based on paleoseismic evidence. The analysis focused on major active faults like North Tehran, North Karaj, Mosha, Taleqan, Firouzkuh, and Pishva.
Ground motion was modeled using NGA-West2 GMPEs, calibrated with local data and integrated into the logic-tree with appropriate weighting. PGA and spectral acceleration (SA at 1.0 s) were computed using Ez-Frisk software for return periods of 475, 975, and 2,475 years. Soil classification was based on Vs30 categories per the fourth edition of Iran’s seismic code (BHRC, 2014).
3-Results and discussion
Tehran’s strategic and demographic importance has made it a key target for seismic hazard mapping efforts. This study’s findings warrant comparison with previous national and international assessments. Although Standard 2800 remains the main reference for seismic design in Iran, its hazard zoning map has seen little change. The current study reveals that the standard overestimates ground acceleration in Tehran, with actual values ranging from 0.1 g to 0.3 g, compared to the code’s fixed 0.35 g and 0.3 g contours. The Global Seismic Hazard Assessment Program (GSHAP) was launched between 1992 and 1999 with the goal of producing comprehensive global seismic hazard maps (Giardini, 1999). Updated versions were later released (Giardini et al., 2013). According to GSHAP data, peak ground acceleration (PGA) values across the Tehran metropolitan area and its surrounding plain range from 0.2 g in the southern parts to 0.5 g in the northern sectors. The Earthquake Model of the Middle East (EMME) project was launched with the aim of providing the most up-to-date seismological insights for the Middle East region and has been regarded as one of the most reliable sources for seismic hazard analysis in the area (Zare et al., 2014). According to the findings of this study, earthquake ground acceleration values in various parts of Tehran and its surrounding plain range from 0.4 g to 0.75 g. One of the most credible and recent seismic hazard studies conducted in Iran, with the involvement of international experts such as Professor Yousef Bozorgnia is the work by Gholipour et al. (2008). The results from the first phase of that study, covering return periods of 475, 975, and 2,475 years, were compared with the findings of the present research for the corresponding study area.
The modeling results indicate that in certain southeastern areas of Tehran, the design peak ground acceleration (PGA) estimated using the optimized logic-tree structure is approximately 0.05 g lower than that suggested by national reference models. According to structural engineering assessments, such a reduction in PGA corresponds to an 8–10% decrease in seismic design loads (FEMA, 2012).
In typical retrofitting projects, this change could result in an average cost reduction of 150,000 to 200,000 IRR per square meter of floor area (ASCE, 2003). For instance, in a building with a 2,000 m² footprint, this would translate into a savings of approximately 300 to 400 million IRR. Thus, employing a refined seismic hazard model can contribute not only to safer structural design but also to the economic optimization of construction and retrofitting efforts.
4- Conclusion

The proposed model improves seismic hazard estimates for Tehran and offers a framework for revising models in similarly situated cities. By excluding inactive faults like those in southern Tehran, the model reduces uncertainties and increases the accuracy of spectral acceleration maps. These results support updates to seismic design codes, urban planning, and retrofitting priorities in high-risk areas, especially southern Tehran.

Abstract Abstract
Determining and studying the crustal strain tensor allows describing geodynamic processes such as stress accumulation, which is an important parameter in seismic hazard assessment. In this study, the geodetic strain rate for the Western Alborz and Azerbaijan regions was calculated using geodetic data and the finite element method. The results of the geodetic strain calculation for the Khoy region show a right-lateral strike-slip shear in the NW-SE direction along with a compressional component. In the northern area of Tabriz, these results show a right-lateral strike-slip shear with a compressional component in the E-W direction in the area around the GhoshaDaghi fault. In the Western Alborz region, the results obtained from the calculation of geodetic strain for the eastern part of the range to the westernmost part of the Rudbar fault show a left-lateral strike-slip shear along the WNW-ESE direction with a tension perpendicular to the structure of the region. The magnitude and direction of the velocity vectors in the northern and southern parts of the western mountain range show a right-lateral strike-slip shear with a tension perpendicular to the mountain range.
Introduction

Calculating and examining geodetic strain as the current active deformation at the surface of the Earth's crust in a region and comparing it with seismic deformations or focal mechanisms of earthquakes occurring in the deep parts of that region as well as deformations in surrounding areas can be helpful both in better understanding active tectonics and in assessing the risk of future earthquakes.
This paper is dedicated to comparing tectonic deformations recorded by geodetic surveys in three separate regions of khoy, Varzaghan, and Rudbar in Iranian Azerbaijan and Western Alborz. Large strike-slip faults and rough mountains are common features of the study areas, and all three areas are directly affected by the northward movement of the Arabian plate and its interaction with the southern Caspian backstop (Solaymani Azad et al., 2019). Seismic hazard is one of the main problems of the study areas, as demonstrated by recent large earthquakes. Since Iran is currently covered by a GPS geodetic network, it is possible to calculate the geodetic strain rate tensor and compare it with seismic strain rate tensors or focal mechanisms of earthquakes that occurred in the region.

Research Method
In this study, the Delaunay triangulation method and geodetic velocity vectors were used to calculate the geodetic strain rate, and the planar velocity gradient tensor was calculated separately for each triangle. In order to calculate the geodetic strain rate tensor and estimate the kinematics of the study area, GPS data published in the article by Khorrami et al. (2019) were used. The velocity vectors used in this study are relative to the Eurasian frame.
The study area was divided into 12 triangular grids in the Rudbar region, 16 triangular grids in the Varzaghan region, and 14 triangular grids in the Khoy region. A GPS station is located at the vertex of each triangle.
Based on the hypothesis that the velocity field v varies linearly within each triangular subnetwork spanning the GPS network, we calculate the average horizontal velocity gradient L = grad(v) on each triangle. Since the velocity gradient generally incorporates both deformation and rotation, this two-dimensional tensor is asymmetric. L can be separated into a symmetric and an antisymmetric part as follows:

Its symmetric part is the strain-rate tensor while its antisymmetric part provides a local measure of the rigid rotation rate (Malvern 1969).

Discussion and Conclusion
To estimate the kinematics of the study area, GPS data published by (Khorrami et al., 2019) were used. The velocity vectors used in this study are relative to the Eurasian fixed frame.
The results obtained from the geodetic strain calculated for the Western Alborz region as well as the velocity vectors used show a left-handed shear in the WNW-ESE direction in the eastern part of the studied area. This left-handed shear is accompanied by a NNE-SSW stretch due to the divergence of the axes of minimum elongation (e2). In the west of the Western Alborz region, the direction of the velocity vectors obtained for the north of the mountain compared to its south shows a right-handed shear in the WNW-ESE direction. The amount of geodetic strain also decreases from east to west and the elongation axes show smaller values. These results are in good agreement with the effects of the interaction of the South Caspian basin on the Arabian-Eurasian convergence in the NNW area of Iran (Soleimani Azad et al., 2019).
Also, according to the results obtained from the calculation of geodetic strain and velocity vectors plotted in the northern region of the North Tabriz Fault, a dextral shear with an approximately east-west trend is visible in this area. Considering the location of the Ghosha-Daghi fault zone (which passes through the middle of this range), it can be related to the function of this fault. This dextral shear is accompanied by its pressure in the WNW-ESE direction, considering the convergence of the axes of minimum elongation (e2) obtained from the geodetic strain calculations. These results also have a good agreement with the tectonic transpression proposed by many researchers in the NW area of Iran (such as; Jackson, 2002; Soleimani-Azad et al., 2015). The geodetic velocity vectors plotted in the functional area of the Siyeh-Cheshme-Khoi fault and its surroundings show a clear dextral shear with a NW-SE trend for this range. This dextral shear is associated with a NNW-SSE orientation due to the convergence of the minimum elongation axes (e2). All velocity vectors obtained from GPS stations located in the northeast of the study area show a clockwise rotation relative to the stations in the southwest of the area, indicating dextral shear in this part of the study area. The Gilato-Siyeh-Cheshme-Khoi, Chaldran and Mako faults, which have a northwest-southeast trend, are located in this zone and each of them could be responsible for attenuating a part of this dextral shear.

Abstract Introduction:
The geochemical study of sediments in water basins such as rivers, estuaries, and seabeds can be an effective step in identifying the source and assessing the distribution model of environmental pollutants in the region. This research focuses on the geochemistry of rock units in the Qarasu River watershed and their contribution to the potential pollution of heavy metals in the sediments of Gorgan Bay. The schists in the area have a fine to medium grain size, and the original rock nature is preserved in most of them. The carbonate-clastic formations of Khush Yilagh and the carbonate of Lar are the most important sedimentary sequences in the studied area.
Method and Result:
 Thin section characteristics and field observations also indicate that most samples related to the Khush Yilagh formation consist of a carbonate matrix and clastic grains such as quartz and feldspar. The Lar formation is primarily composed of pure carbonate, including calcite and dolomite mineralogy. In the studied samples from this formation, rhombohedral dolomite crystals are well observed. 
Ultimately, the results of the geochemical data analysis showed that there is a significant similarity between sediment and rock samples, as well as between heavy metals in all three types of samples (rock, sediment, and water), indicating a common source for these metals. The concentrations of heavy metals in the studied samples are approximately: cobalt 1-27 (average 13), chromium 134-7 (average 88), copper 6-59 (average 32), nickel 1-76 (average 42), lead 1-49 (average 23), vanadium 8-185 (average 100), and zinc 9-157 (average 99) in ppm. 
Discussion:
The concentration of heavy metals gradually increases as one moves away from the river source towards the shores of Gorgan Bay. Overall, the main source of heavy metals is primarily the Gorgan schist and the Shamsak formation. Human involvement in the concentration of heavy metals in the Qarasu River and the shores of Gorgan Bay is very low and rare.
The geological units that are the most important study area with the greatest extent in the Qara Su watershed include the Gorgan schists, Khush Yalaq, Shamshek, and Lar. These units, due to their varying extents, are located at different distances from the riverbed. The Qara Su River and its various branches pass through these units and are often influenced by these substrates. This affects the sedimentary components of the riverbed and its geochemistry. In most cases, there is a positive correlation coefficient between the concentrations of heavy metals and the distance of the river from the geological units, with values above 0.5, indicating that a significant amount of heavy metals is controlled by the geological units of the region. Based on the data and evidence from this study, it can be stated that the main sources of cobalt and copper are from the Shamshek and Gorgan schist units, while the main sources of lead, chromium, nickel, vanadium, and zinc are supplied by the Shamshek, Lar, Gorgan schist units, and alluvial sediments. Although the primary cause of heavy metal accumulation in all samples is the geological units, for some heavy metals like chromium, vanadium, and zinc, anthropogenic factors are also significantly relevant.
Conclusion:
The chemical characteristics of water were examined, emphasizing elements and heavy metals, and the role of lithostratigraphic units in the pollution of elements and heavy metals in the Qara Su river (which subsequently leads to the pollution of the Gorgan Bay) was addressed. In Figure 7, a dendritic diagram has been drawn for rock samples. According to the diagram, except for calcium, elements can be divided into three groups. Magnesium and sodium each form a single-member group. However, in the most important and largest group, the heavy elements are observed together. This fact clearly indicates a common source for most of these elements (Olatunde et al., 2014; Zhang et al., 2016). In Figure 8, this diagram has also been drawn for the sediments of the Qara Su River. This diagram and the grouping relationships of the elements in it bear a strong resemblance to the clustering diagram of elements related to rock samples. As seen in the figure, in these samples, except for calcium, three distinct groups of elements can also be observed. Just like the rock samples, the two elements magnesium and sodium each form a group on their own. The largest and most important group in the clustering of elements in the rock samples, which is very similar to the rock sample, encompasses most elements, especially heavy elements."