Quaternary Journal of Iran

Abstract 1-Introduction
Geology refers to tectonic processes that create changes in the earth's crust during a time scale. Most transformations are important for human societies. Studying the geology of an area is very important in assessing the risk for that area, especially in areas where the amount of tectonic activity during the Holocene and Upper Pleistocene is high, these studies will be important. Although tectonics is the gradual breaking of the earth's crust, which may damage human-made structures, but most of the processes that cause sudden events are important. Based on this, knowledge of the terrain-structure in a region can reduce the risks of sudden events (such as earthquakes) (Keller & Pinter, 2002).
The surface rupture zone of an earthquake fault is defined as the distance from the fault where all structures and facilities face the direct risk of structural rupture, regardless of their vulnerability. Based on this, any type of facility and structure, with any degree of retrofitting, will not be able to deal with surface cracking, and there is no option other than changing the location of the structure for the safety of the structure (CDC, 2002).
The purpose of this research is to investigate the evidence of active tectonics and activity of the Kundaj fault in the Quaternary, which will be done through field observations of trenches in the alluviums and alluvial cones of the investigated area, and it will be tried to clarify the location of the Kundaj fault in alluvial areas.

2-Materials and methods
The investigated area covers the distance between the city of Abek and Qazvin, and in this area, the evidence of the activity of the Quaternary Kundaj fault has been examined. The location of the Kundaj fault is shown on the geological maps in Figure No. (1). As can be seen in the map the Kundaj fault has been identified in a small area and its approximate length is 4 km, and in the 1:100,000 map, the approximate length is 30 km. This fault has been taken into account, and about 9 km of it has been determined, and the rest of the length of the fault, which passes through the Quaternary alluvial zone, is a dashed line, and its exact location is not known. In this research, the location of the fault has been identified and verified.
The research method in the current study is based on library studies and field observations. In this regard, the information related to the geological and geo-structural situation is examined in a library form, and then the evidence of faulting in Quaternes alluviums is discussed in relation to the field investigations. After completing the geological information, evidence of faults and studies of Quaternary alluviums and location of evidence of fault activity, data analysis has been done. Finally, by analyzing the results of the comparison of investigations and evidences of fault and Quaternary activity, the position of Kondaj fault and its Quaternary activity are evaluated.

3-Results and discussion
On the geological maps with a scale of 1:250,000 and 1:100,000, in most parts, it was displayed with a dashed line or it was hidden under the alluvium. This fault has cut Quaternary alluvium in many parts of its length. To determine the location of the fault in the alluvium, it is necessary to dig a trench and prove displacement in the Quaternary alluvium. Therefore, in this research, due to the impossibility of digging a trench due to its high costs, field visits were made to all the north-south waterways located along the fault. More than 50 large and small north-south watercourses cut the fault line, among which there are larger watercourses that have been dug in the bottom of the watercourse due to the high volume of water and intact walls of the watercourse trench where different layers of alluvium can be seen. They were selected for the field visit, the number of which was 8 waterways. Among these waterways, some of them have no evidence of faults and it was not possible to pick up the traces of fault activity in them. Only in three cases of waterway trenches, evidence of faulting and its activity was observed, which will be explained below.
As a result of the investigations, the traces and evidences of fault activity were investigated in three cases of waterway trenches, including the waterways of Behjat Abad, Jezmeh and Falizan villages, and evidence of fault activity, including cutting of alluvial layers and their displacement, was observed in 11 points, and the slope of the fault plane was measured. Various values were measured from 27 degrees to 56 degrees to the north, according to the location of the investigated locations, the average slope of the Kondaj fault plane was about 48 to 55 degrees to the north, and the measured slope of the fault plane was about He attributed 27 to 36 degrees to the branch of the fault. In the south of Behjat Abad village, a case of a fault spring was also observed, which is a proof of the fault zone in the mentioned area.
4- Conclusion
According to the field observations, the location of the fault in the Quaternary alluviums of about 11 km in the south of the villages of Behjat Abad, Tashe Abad and Jezmeh was corrected according to the geological maps, which is shown in Figure No. (19). In the 1:100,000 geological map of Qazvin, the Kundaj fault is located on the border between the Eap6 and Eab6 units with alluvium, and the location of the fault within the Quaternary alluvium was verified by field observations. In the rest, the length of the fault is 3.5 km from Dar al-Soror village to the east and 9.5 km from Khazinabad village to the vicinity of Anjilaq village. The results of the investigations are consistent with the position determined for Kundaj fault in the geological map. In the field investigations, the average horizontal and vertical displacement of the fault was measured as 22 ± 5 and 32 ± 5 cm, respectively.

Abstract 1- Introduction

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 paleo climatic changes indexes can give a better understanding of climate changes in the past era and its causes. Lake sediments have an extraordinary potantial to record climatic and environmental events with high sensitivity and resolution amounts. Therefore, lake sediments can be considered as regions for detecting paleo environments. Chegarman 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 analyze, Elemental ratios, identification of sedimentary facies, and identification of sedimentary environments and changes of these environments set to the reformation the climatic and environmental conditions of Chegarman wetland in the Late Holocene.



2- Methods and Findings

The steps of this research include book studies, field works, laboratory works, statistical data processing and then interpretation and conclusion. To investigate the paleoclimate and conditions of the sedimentary environment, one intact sediment cores with a maximum depth of 7.2 m collected with using Auger corer. 21sediment samples were selected for elemental analysis with ICP-OES and XRF (X-Ray fluorescence). Statistical parameters, histogram diagrams of element frequency and cluster analysis were performed to determine the relationships between the elements in SPSS software. In this study, elemental ratios of V/Cr, Mn/Al, K/Al, Rb/Al, Si/Fe, Ti/K were used to reconstruction of the paleo 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.



3- Results and discussion

In the studied core, 5 major sedimentary facies identified. Facies often contains clay, silt, 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. Two wetland sedimentary and alluvial environments identified. According to the Chronology, the average sedimentation rate in the Chegarman wetland is 1.4 mm / year, which this amount is different for various depths (Darvishi et al., 2022). Due to the type of sediments, the high level water period of the Chegarman wetland has been established between 1250 and 150 years ago. The study of the facies sediments of the wetland bed shows that climate change occurred gradually (not suddenly) about 1250 years ago and this trend has taken at least 300 years. The relatively dry and cold period lasted about 1850 years from 3100 years to 1250 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 4000 years ago to about 3100 years ago, stable and slow wetland conditions was 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 900 years, has been accompanied by extremely humid conditions, high groundwater level and activity of springs in the region. The existence of light brown mud which has the age ranges from 4900 to 4000 years ago, indicates a dry period (900 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 100 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 5000 years ago). At depths of 7 to 7.2 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.



4. Conclusion

According to the results of surveys in the Chegarman wetland, at least 2 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.

Abstract Calcareous nannoplanktons are present in today's oceans significantly (Young & Bown, 1997, Thibault et al., 2012). As Coccolithophores, they are among the calcareous marine phytoplankton that live in oceanic waters and light seawater. Many have thought that the function of Coccolithus is light for photosynthesis for Coccolithophores (Gartner & Bukry, 1969). Coccolithophores, due to having chlorophyll, make the necessary food by themselves. Coccolithophores are involved in the preparation of biochemical limestones. Calcareous nannoplanktons emerged from the Norian and Rhaetian ages, during the Triassic as very primitive and simple organisms. These organisms spread in all seas and oceans during the Jurassic and Cretaceous periods and reached their development in the Cenozoic. Calcareous nannoplanktons found from the current Triassic period to the recent era and the benefits of their study in the fields of paleontology, paleoecology, and biogeochemistry are of great importance.
Researchers such as Jalili and Hadavi (1399); Hadavi (1387); Martini (1971); Kassler (1971) and Hilbert et al. (1981) conducted studies on the sediments of the Persian Gulf. Bioluminescence properties in seawater from bacteria that live in seawater. These bacteria are Photorhabdus, Shewanella, Vibrio, and Aliivibrio, which produce luciferase enzyme and live in the body of nannoplankton. The accumulation of nannoplankton near the shores at night causes the waters to glow. By presenting detailed studies in the fields of biology, paleontology, and microbiology, this research clarifies the role of nannoplankton in the current and past ecosystems. The purpose of this study is to investigate and understand the spread of calcareous micro-organisms in four strategic regions of the Persian Gulf and the relationship with their bioluminescence characteristics in this region.
Materials and Methods
This study was carried out in the identification of Holocene calcareous nannoplankton (Megaline) in four regions of the Persian Gulf. Eight samples were collected and studied from the surface waters of the western and southern Hormuz Island in Feb. 2018 and Feb. 2023, the beaches of Bushehr in, April 2017; the coral beaches of Kish Feb. 2018, and the west of Lawan Island in August 2021. These studies are carried out based on the determination of the species based on systematics and a series of PCR tests to investigate the bioluminescence characteristics of bacteria in BHI agar and BHI broth to determine the volume of the luciferase enzyme that causes bioluminescence.
Results and discussion
Analysis and samples of eight areas indicate that this nannoplankton can withstand high temperatures (more than 17 degrees Celsius), characteristics that were expected to be achieved due to the special weather conditions and high evaporation in the Persian Gulf.
Studies also show that many species of tropical limestones such as Coccolithus palgicus, Gephyrocapsa oceanica، Helicosphaera carteri ، Reticulofenestra minutula ،Cyclicargolithus abisectus، Syracosphaera pulchra ،Pseudoemiliania ovata، Gephyrocapsa ericsonii ،Retecapsa angustiforata و Emiliania huxleyi are present in these areas. These species help regulate carbon in marine ecosystems and play a significant role in the environmental cycle.
Among the available nannoplankton from Nannoliths, Diatomite, Heterococcoliths, and Holococcolithes, in total, 41 species from 14 genera were identified. You can also see diatoms that live in marine environments.
Microbiology and biology studies on Persian Gulf water samples have shown the presence of a group of light-producing bacteria including Photorhabdus, Shewanella, Vibrio, and Aliivibrio that live in the seas. These bacteria produce luciferase enzyme and thus produce light in the visible range. In this study, only in one of the samples related to the waters of Lawan Island, very little of the optical characteristics of these samples can be seen, and the reason for this is the inappropriate storage of the waters for the test sample.
Conclusions
This study has been conducted on the biological diversity of calcareous nannoplankton from the seawaters of four regions and eight samples of the Persian Gulf, from the western and southern Hormuz Island in February 2018 and February 2023, the beaches of Bushehr in, April 2017; the coral beaches of Kish February 2018, and the west of Lawan Island in August 2021. In this research, 41 species of 14 genera of calcareous nannoplanktons were identified, which shows the richness and biological diversity in these areas.
Species with high abundance such as Gephyrocapsa oceanica, Helicosphaera carteri, Coccolithus plagicus, and Emiliania huxleyi, Holococcolithes were observed. These findings are very important because some of these species that originated from the Paleocene or Cretaceous periods such as Coccolithus plagicus, Retecapsa angustiforata, and Braarudosphaera bigelowii are still present in the seas of the present era. They can provide valuable information on the environmental history of the Persian Gulf. Also, PCR tests were performed to determine the presence of bioluminescence agents in the samples. Despite the evidence of a small presence of light-producing bacteria such as Vibrio and Aliivibrio that produce luciferase enzyme, they exist in seawater. According to the richness of nannoplankton observed, it can be concluded that Persian Gulf waters have the highest level of primary productivity and nutrients are sufficient to support different microbial and planktonic populations

Abstract Paleosols consist of soils formed under climate conditions different from the present day, consequently their physical properties are regarded as an indicator for past climate condition. Loess investigation have received considerable attention in twenty century. Loess- Paleosol sequences in Central Aia have attracted the attention of loess researchers. Major loess areas in Central Asia are located in the southern Tajikistan. The paleosols sequences in the loess sediments in the southern Tajikistan, which can reach thicknesses of 200 m- is a key area of environmental changes of Central Asia. Loess-paleosols sequences of the southern Tajikistan prove the cold and dry climate through loess deposition and the warm and humid climate during the formation of the paleosols. Tajikistan is a mountainous country which is surrounded by mountains to the north, east and south and the desert of central Asia to the west. The climate of Tajikistan is continental, subtropical and Semiarid, with drastic changes according to elevation. The Khonako II sedimentary section studied (latitude 38.35959 N, longitude 70.04552 E) is situated in southern Tajikistan. Present-day climate in southern Tajikistan is Mediterranean, with dry summers and seasonal precipitation spanning from early winter to spring. Recently micromorplological studies have not been published from this regin. The purpose of this study were to investigate the micromorphology of loess-paleosol sequences in the southern Tajikistan as well as compare the weathering and evolution of th loess and paleosol sequences of Tajikistan and Iran. The loess-paleosol section was described and undisturbed samples were collected from thin section analyses. Thin section study of paleosols is a uniqe method to study pedological changes in the past and paleoenvironmental reconstruction. The micromorphological index of soil development (MISECA), in which several micropedological feature (microstructure, b-fabric, the presence of clay coating, decalcified zons, Fe/Mn oxides and degree of alteration of mineral grains) explain accurate infoemation of the degree of soil development in the past in different horizons. Based on increasing grade of soil Evolution, the MISECA index ranges from 0 to 24. In the studied section, a modern soil (MS) including an ochric epipedon, and cambic and calcic subsurface horizons as well as twelve loess sequences(L) and sixteen pedocomplexes (PC), which are covered by thick (∼12000 cm) loess deposits and different types of interstadial and interglacial paleosols were identified. The micromorphological investigations indicate that the accumulation of clay illuviation, pedogenic calcium carbonate and depletion of the soil carbonate are the predominant processes in these soils. Various types of calcitic pedofeatures are recognized in the modern soil which imply that coating and hypocoating of secondary carbonates around channels result from later recalcification processes. The observed voids contain of planes, vughs, channel and chamber. Channels and chambers in the modern soil, some loess units and paleosols are attributed to biological activity. The dominant microstructure of modern soil is crumb due to organic matter. The microstructure differ from waekly-separated angular (subangular) blocky in the pedocomplexes with a lower degree of development to well-separates angular (subangular) blocky in the pedocomplexes with a higger degree of development. In PC10 clay coatings super imposed on carbonate coatings, and in turn covered by calcite, demonstrates recalcification. a crystallitic b-fabric were seen in soils with a higher amount of calcium carbonate. However, the part of argillic horizons was mostly dominated by spckled b-fabric, which demonstrates the process of translocation and subsequent accumulation of clay as a result of water percolation. Clay pedofeatures were recognize as clay coating along the channels. Disruption by swelling and shrinking in soil is the main factor responsible for the lower amount or lack of clay coatings in PC1. The appearance of numerous redoximorphic features in PC7 and PC8 in comparison to the other pedocomplexes indicate periodical saturation due to higher precipitation. Generally, large amounts of clay coatings, iron and manganese oxides pedofeatures, and biological activities features indicated the high development of paleosols compared to the loess layers. Investigation of micromorphological soil development index (MISECA Index) as a measure of soil development showed weak development for modern soil, in contrast of moderately to well-developed of paleosols due to having oriented clay coatings and iron and manganese oxides on soil grains or channels. Variations of MISECA index values of modern soil compared to paleosols demonstrates that paleosols were formed in the more humid conditions.

Abstract Investigating the level of pollution and assessing the environmental risk of soil to polycyclic aromatic compounds in Ahvaz oil field using ERL, ERM, and TEF index





Introduction



Polycyclic aromatic hydrocarbons (PAHs) are of greater concern among petroleum hydrocarbons due to their toxicity, low evaporation, resistance to microbial degradation, and high tendency to form deposits. Oil spills usually hurt soil biodiversity. Most soils containing bacteria that can absorb high amounts of hydrocarbons may have the ability to reduce aliphatic and aromatic hydrocarbons. Researchers have concluded that soil containing 2-3% crude oil has the highest number of microorganisms compared to typical soils. It is also reported in research that 8 months after soil contamination with oil, oil-degrading bacteria grew 10 times and accounted for about 5% of the soil microbial population. The presence of petroleum hydrocarbons in the soil leads to major changes in its physicochemical and biological properties. For example, with the entry of sewage, the TDS of the soil usually increases, which leads to a decrease in soil fertility. According to Aniagor et al., oil pollution remains in the soil for more than a hundred years. Soil pollution with petroleum substances is considered one of the world's environmental problems. The accumulation of oil pollutants in the environment has caused a lot of challenges because the soil contaminated with these compounds is unfavorable for agricultural, industrial, or recreational purposes, and it is also considered a potential source for polluting surface and underground water. Therefore, this research was conducted to investigate the level of contamination and assess the biological risk of soil to polycyclic aromatic compounds in the Ahvaz oil field using ERL, ERM, and TEF indices.



Materials and methods

The current descriptive-applied research was conducted in 1402. The studied area includes the soil of 4 oil centers (an oil exploitation, a desalination unit, an oil rig, and an oil pump house) in the southwest of Iran. Samples were taken from 20 locations within 4 oil centers (5 samples within each oil center) with three repetitions. For this purpose, topsoil was removed from 20 stations in the study area using a grab van with a cross-sectional area of 0.1 square meters using a winch tool from a depth of 10 to 14 cm.



Results and discussion

Results of Concentration of PAH in soil samples



The total amount of PAHs among the sampling areas ranges from 9.87 to 2632.688 μg/kg, with an average of 2373.44 μg/kg. The average concentration of compounds with low molecular weight (LMW two and three rings) is 347.152 μg/kg and the average concentration of compounds with high molecular weight (HMW four, five, and six rings) is 60.24 μg/kg. In general, the classification based on the total concentration for PAHs in sediments includes 3 groups: if the total concentration is more than 500 μg/kg as highly polluted, the total concentration is between 250 and 500 μg/kg is moderately polluted and if the concentration is less than 250 μg/kg If it is a kilogram, the pollution is insignificant. Qualitative effects guidelines are also used to correlate effects and total and individual PAH chemical concentrations. Based on this, 30.4% of the stations had very high pollution, 15.17% of the stations had moderate pollution and the rest had low pollution levels.

It was determined that the cyclic aromatic Indene[1,2,3-cd]pyrene (IndPy) with 13.47 has the lowest average PAH and the cyclic aromatic Phenanthrene (Phen) has the highest average PAH with 721.54 μg/kg in the studied area. Also, it was found that Fluoranthene (Flu) and Acenaphthene (Ace) have the lowest ERM. It should be noted that the ERM index could not be calculated for the rest of the cyclic aromatics. Based on the results, Anthracene (Ant) and Acenaphthene (Ace) have the lowest ERL. It should be noted that the ERL index could not be calculated for the rest of the cyclic aromatics. High concentrations of PAHs in soil can have harmful effects on the environment and human health. Due to their lipophilic properties, these compounds are easily accumulated in fat tissues and are transferred to living organisms through the food chain. Studies have shown that some PAHs can be carcinogenic and increase the risk of various types of cancer by causing genetic changes in cells. In addition, the presence of PAHs in aquatic environments can lead to a decrease in water and soil quality and affect aquatic life by affecting biological processes such as photosynthesis and cellular respiration.



Conclusion

Continuous and accurate monitoring of PAH concentration in soils and waters near oil centers is of great importance. This monitoring can help identify sources of pollution and assess environmental risks. Also, the development and implementation of pollution management programs that include the use of cleaner technologies, improvement of wastewater treatment processes, and leakage control can help reduce the pollution load of PAHs. Education and increasing public awareness about the dangers of PAHs and the importance of protecting the environment are also other necessary measures in this field.





Keywords: Soil Pollution, Petroleum Compounds, Polycyclic Aromatic Hydrocarbons

(PAHs)

Abstract Introduction

Mangrove forests are dynamic coastal environments where climatic conditions and water levels lead to diverse chemical, physical and biological environmental changes in different time frames, which are recorded in their sediments. In this study, physicochemical (grain size, magnetic susceptibility, total organic carbon, colour, bulk density and porosity) and biological (diversity and abundance of benthic foraminifera) data from a radiocarbon-dated sedimentary core from Azini Creek were used to reconstruct palaeoenvironmental and the relative sea level change in Sirik mangrove during the last 2700 years.



Materials and Methods

The estuaries of the Sirik region are located between 26°15' to 26°25' N and 57°4' to 57°8' E with an area of 3500 km2 in Hormozgan province, at the boundary between the Oman Sea and the Strait of Hormuz. This area is the only estuary with two mangrove trees containing Avicennia marina (Hara) and Rhizophora mucronata (Chandal). Core Az (1.5 m long) was collected within the mangrove of the Azini Creek, using a 7 cm diameter Russian peat sampler. Physiochemical and biological analysis of sediments (magnetic susceptibility, grain size, total organic carbon %, colour, porosity bulk density and foraminiferal assemblage) were performed. One radiocarbon age was determined in the Poznan laboratory by the AMS radiocarbon method.



Results and discussion

The radiocarbon age of depth 144-146 cm shows that the base of the core ages about 2700 cal. yr BP. Based on physiochemical and biological parameters the core Az was subdivided into five units of A-E. In core Az, a total of 66 foraminifera species were identified, encompassing 24 genera and 20 families. Among these species, 44 are characterized by hyaline tests, 20 by porcelaneous tests, and 9 by agglutinated tests. Sediments of core AZ are not very diverse and are all composed of sandy silt and sandy mud. Unit A is composed of olive green (5Y-5/2) sandy silt with the highest magnetic susceptibility (6.3×10-5 SI) and foraminiferal diversity (mean 17 species in 10 cm3) belonging to three groups (shallow marine environment). In unit B, sand content decreases by 50% and sediments turn to sandy mud. In this unit frequency and diversity of foraminifera decrease and porcelaneous taxa disappear (playa-lagoon). In unit C sand content (mean: 38%) and frequency of foraminifera increases again (4600). This unit represents a low mangrove adjacent to the tidal channel. In units D and E sand content decreases gradually and organic carbon and plant remains increase dramatically. Concurrence of agglutinate and opportunistic hyaline taxa suggest the provenance of mangroves in the area.

The results showed that from 2700 to 1800 years ago, the relative sea level was about 1m higher than that of today and fluvial input to the area was higher than the present. At the end of this period, the decreasing trend in the relative sea level and humidity caused the relatively humid marginal coastal environment to become a shallow playa environment. From 1400 to 1800 years ago, stabilizing the relative sea level led to the expansion of tidal channels, which provided a suitable environment for the initiation of mangroves. At this time, the gradual decrease in temperature caused a relative increase in Mediterranean winter precipitation. This climatic optimum period is traceable in other parts of the Iranian Plateau and the Near East. During the last 1400 years, the development of the mangroves began in the region. This mangrove evolution matches to the mangrove growth in the Gowatr (SE extreme of Iran) and Khuran (west of Hormuz Strait). This period coincides with the relative dryness with high climatic fluctuations. In this period gradual increase in winter temperature caused the northward migration of winter westerlies and therefore reduction in winter precipitation. This climatic deterioration is observed in other parts of the Iranian Plateau.



Conclusion

With an age of about 4000 years, the Gowatr mangrove is the oldest in Iran. 2500 years later, mangroves entered the Strait of Hormoz in Sirik and Khuran. During the last 3000 years changes in the earth's orbit around the sun caused the mean annual sea surface temperature in the Oman Sea and the Persian Gulf has increase between 2-3 degrees Celsius, which is the result of an increase in the average winter air temperature. This study shows that during warmer periods, the northward movement of winter westerly winds causes a decrease in winter precipitation in the area.





Keywords: Azini, Mediterranean winter precipitation, Chandal, Harra, Foraminifera



Acknowledgements

This investigation evolved from a research project entitled: "The history of appearance and evolution of Iranian mangroves since the Mid-Holocene and its link to the climate and sea level change", being supported by a grant from the Iran National Science Foundation (INSF) (No. 99017678).

Abstract 1-Introduction
Rivers, as the most important factor in changing earth landscape, have been more effective than any other factor in shaping the human living environment. The understanding of the river processes and the factors controlling the behavior of rivers is important from different perspectives, including sedimentology. Examining textural characteristics, facies analysis and statistical indicators of river sediments, in addition to civil applications, can be a useful tool in the interpretation of ancient river sedimentary environments. In addition, the study of the behavior and nature of rivers and, accordingly, the study of watersheds from several aspects such as flood control, erosion and sedimentation have been of interest. The Afin River catchment is located in Southern Khorasan province and in the southeastern of Qayen. This river is the main source of agricultural water supply for villages located in this basin and has the greatest impact in terms of sediment production in the catchment area of Haji Abad Dam. The main purpose of this research is 1) to investigate sedimentological characteristics (textural parameters) and determine the effective factors in creating sedimentary discontinuities, and 2) to identify lithofacies and present a sedimentary model of the Afin River.
2-Materials and Methods
During the field study, 55 samples were taken from the channel bottom sediments by digging holes with a depth of 20 cm and with regular sampling intervals from the upstream to the downstream of the stream for grain measurement testing and the geographical location and height of each the sample was recorded by GPS. The active parts of the river channel have been selected for sampling. After sediment drying in the laboratory, the collected samples were analyzed using the dry sieve method with an accuracy of 0.02 grams. The results of the granulometry were drawn by Excel software in the form of histogram and cumulative curves, and the naming of the sediments was done according to Folk''s (1974) classification. Statistical parameters such as mean, median, skewness, and kurtosis were calculated for each of the samples using Folk''s comprehensive drawing method. In the field studies, the textural characteristics and sedimentary structures of the river channel wall sediments from upstream to downstream have been investigated and sedimentary facies have been separated based on Mial''s (2006) classification. In this study, the EPM model was used to calculate the annual erosion rate in the Afin River catchment.
3-Results and Discussion
Sedimentological studies of the Afin River show that several factors such as the entry of a large volume of coarse-grained sediments by sub-branches (inflow of lateral sediments), active tectonics, lithological changes and bedrock outcrops that cause to change textural parameters such as mean, median, standard deviation, skewness and kurtosis and have created an irregular grain finning trend from upstream to downstream. In the sediments of the Afin river channel wall, there are three clastic facies association (including the five gravelly facies Gcm, Gmm, Gt, Gh, Gp, the five sandy facies Sh, Sm, Sl, Sp, Sr and one mud facies Fm) and non-clastic pedogenic carbonates (P) have been identified, that based on them and other sedimentological features, five architectural elements such as SG, SB, CH, FF, GB have been separated. Two sedimentary facies models have been proposed for Afin River in the southeastern of Qayen. In the upstream part, this river is a gravel bed braided river with sediment gravity flow deposits, and in the middle and downstream part of the river, it is like a shallow gravel bed braided river.
4-Conclusion
The Afin River catchment with an area of 1181 square kilometers is located in the southeastern of Qayen city (Southern Khorasan province). In order to study of the finning trend of Afin river particles, 55 sediment samples from the main channel have been examined. The results of the granulometry analysis show that the finning trend of particles towards the downstream of the stream does not have a uniform trend and includes 6 sedimentary continuities and 5 sedimentary discontinuities. The arrival of coarse-grained sediments from tributary rivers, lithological changes, tectonic activities, and the appearance of bedrock are the most important factors in creating of these sedimentary discontinuities. Identification of the sedimentary lithofacies in the channel wall of the studied river was done based on textural features and sedimentary structures, which clastic facies associations (gravel, sand and clay) and non-clastic (pedogenic carbonates) are separated from each other. According to the sedimentary facies and architectural elements (CH, GB, SG, SB and FF) that are identified in the channel wall of the Afin River, two types of river channel styles proposed for the upstream to downstream sections of this river and the corresponding sedimentary facies model is provided.
Keywords: Sedimentary link, Southern Khorasan, Lithofacies, River channel style.

Abstract The purpose of this research is to investigate the folding and shortening within the northern Kerman coalfield area, which is part of the tectonically active regions due to the structural diversity of the Earth's crust. The main deformation in this area has been influenced by the stresses resulting from compression and extension in central Iran, resulting in folding and faulting. The Koohbanan fault is one of the most significant structures in this region, causing various structural changes in the northern Kerman coalfield during the Quaternary period. By examining folding and analyzing the shortening resulting from the faults in the cross-sectional domain, which exhibit a syncline arrangement with their axes inclined relative to the main cross-sectional axis, we can attribute it to the compressional stress induced by the right-lateral movement of the Koohbanan fault.

Around 40% of the foldings are the result of compressional stress during the Alpine tectonic events. Based on the conducted studies, evidence suggests that the folds in the region are compressed from both sides towards the center, forming new folds at both ends. The complete sequence of pre-folding and post-folding flexural structures, notably faults, suggests that except for the Koohbanan and Tarz faults, which played a significant role in the formation of the northern Kerman coalfield basin and existed prior to folding, the remaining faults in the region have developed after the formation of the folds. This implies that most of these faults are the result of folding-related stress, with their formation occurring post-folding.

In conclusion, this research delves into the dynamics of folding and shortening in the northern Kerman coalfield area. The study highlights the interplay of tectonic forces, particularly compressional stresses, in shaping the geological features of the region. The analysis of faulting and folding provides insights into the tectonic history of the area and sheds light on the complexities of structural deformation in response to the broader tectonic context.

The studied area is, in fact, the northern part of the Kerman coalfield region, known as the Kerman Coal Basin (Technosport 1969 report). The Kerman Coal Basin is situated in the southeastern portion of the Kerman-Baft synclinorium. This tectono-sedimentary region is bordered by the Urmia-Dokhtar volcanic zone to the south, the Ravar-Kalmardeh heights to the north, the Bafq-Saghend heights to the northwest, and the Lekrkouh heights to the east and southeast. The mentioned synclinorium is bounded by the Koohbanan fault to the southwest and the Baft-Tarz fault to the northeast.

The Kerman-Baft synclinorium consists of various structures with distinct lithological characteristics and different formation histories. These are elaborated below:

The first litho-structural unit pertains to the deformed arkosic sandstones and quartz arenites of Cambrian origin, belonging to the Iran-Arabian platform. These rocks have undergone significant deformation during the Cretaceous tectonic phase of the Katangian Orogeny. The outcrop of this unit is also observable beyond the coal basin area.

The second litho-structural unit encompasses a thick sequence of Upper Permian to Upper Jurassic deposits, which are separated from their underlying and overlying units by pronounced unconformities with steep angular discordance.

The Kerman-Baft synclinorium is geologically characterized by these diverse litho-structural units, each with its own unique sedimentary and tectonic history. The synclinorium's location within the larger tectonic context, bounded by significant faults and surrounded by different geological features, plays a crucial role in shaping its geological evolution and landscape.
By examining the style of faulting within the designated area, several points can be inferred regarding these matters, as follows:

From the assessment of the degree of closure in folds, it can be deduced that Naybandi Feizabad, Hamkar, and Baghpahn folds are, respectively, the most tightly compressed folds, situated predominantly in the northern and northeastern parts of the region. If we consider the degree of compression as indicative of the timing of deformation, looking at Figures 1 and 2, it becomes evident that the initial signs of folding occurred in the eastern portion of the basin. Subsequently, the folding progressed from the margins towards the center of the basin. This initial deformation initially impacted the northern part of the basin and gradually progressed towards the southeastern sections over time.

The classification of folds based on their apparent ratios is closely related to the degree of compression. More compressed folds correspond to taller folds, while less compressed folds are associated with shorter folds.

By analyzing the values of 'b' related to the folds, it is apparent that they mostly lie between angular to sharp-angled folds. However, a notable point is that the value of 'b' is directly related to the magnitude of the fold's effect. Smaller folds have lower 'b' values (steep and angular folds), while larger folds possess higher 'b' values (semi-angular and semi-circular folds).

Regarding the orientation perpendicular to the axis of Bagh Pahn, Bagh Tappeh, Hamkar, and Feizabad folds, it can be stated that the compression of the folds occurs from both sides towards the center. Another observation is that the wider angle between the two limbs of the Moryn and Mine 12 folds at the Heshooni narrows suggests the formation of new folds with a similar mechanism at both ends. These observations offer a complete representation of a folded belt, showcasing the formation of folds from initial stages to compression and refolding within a chronological sequence.

Determining the synchronicity or asynchronicity of ductile and brittle tectonic events poses one of the most challenging aspects of structural analysis. For the studied area, this can only be deduced to some extent through the truncation of folds by faults. However, a full sequence of pre-folding and post-folding flexural structures can only be established through absolute age determinations. Nevertheless, due to the truncation of most fold limbs by faults in the region, it can cautiously be suggested that, except for the Koohbanan and Tarz faults, which played a significant role in the formation of the coalfield basin and existed prior to folding, the other faults in the area developed after the formation of the folds. In conclusion, this has given rise to the following structural pattern.

Abstract Introduction: Water and soil resources and especially the vegetation cover in the belt areas of the deserts of Iran have provided conditions that cause and intensify desertification and their expansion on the edge of the deserts. Therefore, under the influence of social and economic changes of at least the last century, this sector has progressed towards a critical situation and its size is increasing day by day. Iran is located in the dry belt of the world and a quarter of Iran's area is covered by desert. According to statistics, 18 provinces in Iran are involved in desertification, and one of these provinces is Semnan province. At present, more than half of the province's area is made up of desert lands, which is approximately 53% of the province's surface, the effects of which can be the destruction of water resources, the destruction of groundwater levels, the destruction of wildlife, the increase of respiratory diseases and named .Most of the lands of Semnan province have a dry and semi-arid climate due to their distance from moisture sources, and about half of the lands of the province lack vegetation. Due to excessive exploitation of biological resources such as pastures, forests and water reserves Underground, as well as the illegal transformation of pasture and forest lands into agricultural lands, most of these areas, even the northern lands of Semnan province, have been severely affected by the phenomenon of desertification.
Materials and methods: In this research, the logistic regression model(LRM) method was used to prepare a map of the vulnerability of Semnan province to desertification. The current method includes the analysis of desert areas with the help of visual observations, measurement, examination and processing of the main indicators using mathematical and statistical models. For this purpose, four independent variables and one dependent variable were used. The independent variables are: vegetation index (NDNI), soil texture index (TGSI) and effective anthropogenic pressure (APSI). and aridity coefficient (AL). Vegetation and soil texture index was obtained from 10 Landsat 8 images. Aridity coefficient was calculated with statistical data of annual rainfall in millimeters and annual evaporation and transpiration in millimeters. The selection of effective human factors in the region has been calculated with the help of AHP method and its map has been prepared. The dependent variable was the Boolean map of areas involved in desertification in Semnan province. With the help of Arc map 10.8.2 and Terrset 2020 software, the coefficient of each of the independent variables has been calculated with the logistic regression method (LRM) and the final risk map of desertification in Semnan province has been obtained.
Results and discussion: The results of the Regional Soil Texture Survey (TGSI) show that almost more than half of the 60% region has land with high sand content. Among the variables, soil texture factor (TGSI) has been more related to desertification. The results (NDVI) show that almost all the vegetation of the studied area was sensitive to desertification, which was covered by the desert steppe. The desert steppe occupies 99% of the area. The aridity index (Al) is dry in the entire region, except for the northern regions, which include 99.6% of the province. The effect of human pressure in the entire province decreases from the north to the south of the province. The highest pressure of human factors is in the northern region of the province, which covers 41.6% of the area of the province. In order to check the R2 rate, the rate was more than 0.2, which indicates the acceptability of the results of this model.
Conclusion: After the classification of the desertification risk map of Semnan Province, which is based on the model (LRM), it was determined that more than 99% of the province's area is at a very severe risk of desertification. The risk of desertification decreases from the south of the province to the north. The north of the province is located in a mountainous region due to its proximity to the Alborz mountain range and the moderate Caspian climate of northern Iran, which has a different climate and vegetation compared to the south. The risk of desertification in the region increases with the decrease in soil quality and vegetation density and weather conditions. The results of the research show the correctness of the LRM model in order to identify areas with a high risk of desertification in Semnan province.

Abstract Abstract

1-Introduction
Based on the geological map of northwestern Iran, as well as the characteristics of the rock structures and the trends of the major faults, there exists a block known as the “Arasbaran Volcanic Belt,” which is bordered by the Tabriz, Miyaneh, Talash, Allahyarlu-Hawai, and Arax faults. The area studied within this block has attracted the attention of many researchers due to its location in a metallogenic zone. A few researchers have focused on the magmatism of this region, identifying it as a result of subduction. The purpose of this research is to investigate the mineralogy and thermobarometry of Plio-Quaternary intermediate and acidic lavas around Beygz Mountain in this block, and to compare these findings with similar occurrences, such as the Sablan Volcano, the Andrian Neogene volcanic rocks (which are part of the Arasbaran magmatic zone), and the Cone Arvana Volcano, located in the eastern part of the Sahand volcanic complex southwest of Bostanabad.

2-Materials and methods
To investigate the various volcanic sequences and their lateral variations, a series of surveys were conducted using both transverse and longitudinal profiles. More than 300 rock samples were collected during these surveys. Based on microscopic examinations, 33 samples with the least alteration effects were selected for geochemical analysis. Additionally, 13 samples were chosen for electron microprobe analysis (EPMA).


3-Results and discussion
Ten distinct lithological types can be identified in the Quaternary volcanic rocks of this area. The intermediate rocks include basaltic trachy-andesite, trachy-andesite, pyroxene andesite, and hornblende andesite, with trachy-andesites being the most abundant. Most of these rocks exhibit a porphyritic texture with a cryptocrystalline or microcrystalline matrix, and they may also display trachytic and vesicular (amygdaloidal) features. The primary minerals in these rocks are feldspar, amphibole, and pyroxene, respectively. The acidic rocks consist of trachydacite, dacite, and rhyodacite, which constitute a smaller volume in the area. These rocks typically have a porphyritic texture with a microcrystalline and trachytic matrix. The main minerals present include feldspar, amphibole, biotite, and quartz. In the older Sablan volcanic rocks, plagioclase, pyroxene, amphibole, biotite, and a small amount of potassium feldspar and quartz can be observed. The younger Sablan volcanic and subvolcanic rocks exhibit porphyritic and hyaloporphyritic textures, with phenocrysts of plagioclase, biotite, hornblende, and quartz found in glassy, microlithic, and fluidal textures.
The volcanic rocks of Arvana contain phenocrysts of plagioclase, hornblende, biotite, and occasionally quartz and feldspar. The primary textures of these rocks are hyaloporphyric and microlithic porphyritic. The Andrian volcanic rocks are primarily composed of alkali feldspar, plagioclase, calcic amphibole, clinopyroxene, and biotite, with textures mainly being microlitic porphyritic to trachytic. In some of the intermediate rocks of the Beygz Mountain area, particularly the andesites, disequilibrium textures such as sieve textures, corroded or bayed margins, opacification of ferromagnesian minerals, and rounding of minerals are observed. These features are indicative of disequilibrium and complex physical-chemical variations in magmatic systems, resulting from the disequilibrium between phenocrysts and the matrix of andesite rocks. Thermobarometry in the Beygz Mountain area has been conducted by calculating the temperature and pressure of amphibole and pyroxene formation. The average pressure obtained for the studied amphibole is approximately 7.5 kbar, with formation temperatures ranging from 1043 °C to 1020 °C. Measurements based on clinopyroxene composition indicate that the formation pressure of this clinopyroxene is around 7 kbar, with a temperature of 1071 °C. Old Sablan pyroxenes crystallized at pressures ranging from 5 to 10 kilobars and at depths of approximately 17.5 to 35 kilometers. The amphibole phenocrysts of young Sablan crystallized at pressures of 1 to 3 kilobars, at depths of about 3.5 to 10.5 kilometers, and at temperatures ranging from 725 °C to 750 °C. Based on the amphibole-plagioclase thermometer and Al barometry data, hornblende in the Arvana volcanic cone has a crystallization temperature between 899 °C and 707 °C, with pressures ranging from 0.5 to 2.9 kbar. In the volcanic rocks of Andrian, thermobarometric measurements have been determined using several methods, yielding a temperature range of 700 °C to 800 °C and pressures between 3 to 6 kilobars.

4- Conclusion
Disequilibrium factors such as plagioclase sieve textures, opacification of ferromagnesian minerals, and rounding of amphibole minerals, along with the incompatibility of pyroxene compositions with the surrounding melt and the reverse zoning of pyroxenes, indicate a disequilibrium between the melt and crystals. These features suggest that magmatic variation processes have occurred within an open thermodynamic system. It is believed that the arrival of new and hot magma pulses caused the magma chamber to migrate from deeper levels (approximately 22.5 km depth and 7.5 kbar pressure) to shallower depths (around 21 km depth and 7 kbar pressure). This increase in temperature and decrease in pressure disrupted the stability conditions of amphibole and facilitated the growth of augite. The occurrence of augite, along with the growth of alkali feldspars on some plagioclase, may indicate magma migration and disequilibrium conditions (approximately 7.2 kbar pressure and 1050 °C temperature). Trachy-andesite volcanic rocks and some acidic samples from the region show evidence of crustal contamination. Based on the temperature and pressure of intermediate and acidic magmas in the Ahar block, it can be inferred that the magma chamber in the Beygz Mountain area is located at greater depths, temperatures, and pressures, and that repeated injections have occurred within the magma chamber. The presence of mafic lavas in this area, along with evidence of magmatic mixing and the injection of mafic magmas into felsic magma, further supports the notion of injection within the magma chamber.

Abstract Introduction
One of the tools for identifying landforms is the use of morphotectonic indicators, the use of these indicators is useful for studying areas that have experienced rapid uplift or tectonic transformation. Longitudinal profile of the river is one of the basic components in the river system and as a key topographical index it shows useful information of lithological, tectonic and erosion changes. The river system is a complex reaction process system in which various variables can play a role in its control, and any change in one of these variables causes the complexity of changes and adjustments in the river system. In geomorphological studies, the longitudinal profile of a river is used as a measure to detect tectonic uplift and changes in rock units, the longitudinal profile of rivers that are in equilibrium is concave, but various factors, including structural factors, change the longitudinal profile of the river . Abnormality in the longitudinal profile of the river, if it is caused by tectonic factors or lithological changes, can cause sudden changes in the slope and is associated with the creation of a kinck point, which can be seen as a waterfall and a rapid. Alborz is located on the southern margin of the Caspian and in the north of Iran. Considering that there are important rivers in the target area that reflect the tectonic conditions of the area and so far the mentioned methods have not been used for this study, the purpose of this study is to investigate the longitudinal profile of the river using MATLAB and GIS software in the area in order to Determining the level of tectonic activity of the main faults in the region.
Methodology
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.
Results and Discussion
The results of a quantitative study of changes in the longitudinal profile of the river and Knickpoint extraction in 50 drainage basins indicate high tectonic activity in the studied area, especially in Sangavard faults, other faults in the south, southeast and southwest of the region. . The index of normal slope (Ksn) and concavity () which was calculated using the longitudinal profile and in MATLAB software; This means that the high values of these indicators show good coordination with the known faults of the region, including the Firouzabad-Majder fault in the studied area. Sangavard fault, based on the numbers obtained from the normal slope index (Ksn) and concavity (), is the most influential fault in increasing the amount of these indicators in the studied area.
In this research, Knickpoint zones were extracted using a new method and their relationship with the structures of the region was studied. Knickpoints are widely spread in the studied area. The correspondence of sharp and steep knickpoints near the base of the mountain with active faults in the area shows that most of them were created by tectonic activity. The effect of lithological features on the frequency and size of knickpoints can be seen in some places, but they play a secondary role after tectonic activity. In this method of extracting fault lines, the location of fault lines corresponding to Sangavard faults, Kiwi fault, Sheikh-Janlu fault, Qalban-Qiyeh fault and faults located in the south, southeast and southwest of the studied area overlap. They are significant with the index of normal slope and concavity. The conformity of the location of Knickpoints in the field observations with the results of softening also confirms the accuracy of the methods used.
The correspondence of the location of Knickpoints in the field observations with Knickpoints extracted by the method mentioned in the previous sections shows the accuracy of the method used. The tectonic evidences obtained from field observations also prove the recent tectonic activity of structures and faults in the region. The existence of landforms such as high alluvial , the creation of triangular facets, the tilting of layers, the creation of narrow valleys, and the existence of V-shaped valleys are in addition to the results of the morphometric indices. Geostructural evidences such as faulting and folding in Neogene and Quaternary units, displacement of Neogene units due to the activity of the aforementioned faults, thrusting of old units on young units, is a strong proof of the high activity of the structures related to the faults in the case.
Conclusion
High tectonic activity in the study area, especially in Sangavard, Niki, Andalibi, Sheikh Janlu, and Qalpan Qepeh faults and other southern faults of the region using quantitative analysis of the river profile and extraction of Knickpoint in MATLAB software and high agreement of the results of quantitative profile studies River with field evidence and seismic history as an acceptable method to identify areas with high tectonic quality.

Abstract The study area is located in the northeastern part of Isfahan province, within the Na’in county, between the Khur and Bayabanak regions, and Ardistan, on the 1:100,000 Anarak geological map sheet. It lies between geographical longitudes ‘30°53’ to ‘54’ and latitudes ‘30°33’ to ‘33’.
The study was conducted using satellite image processing techniques with Landsat 7 (Enhanced Thematic Mapper Plus - ETM+) and Landsat 8 (Operational Land Imager - OLI and Thermal Infrared Sensor - TIRS) sensors. The following techniques were employed:
1. Band Ratio: Used to mitigate topographic and shadow effects and enhance mineral visibility.
2. Normalized Difference Vegetation Index (NDVI): Highlighted vegetation in the area.
3. RGB Color Combination: Separated lithological units based on color.
4. Filter Applications (Sunangle, Highpass, Edges): Enhanced fault lines, boundaries, and sharp edges.
5. Digital Elevation Model (DEM): Utilized ASTER DEM at a 1:10,000 scale to create a 3D model of the region, enhancing visibility in valleys through shadow creation.
6. Principal Component Analysis (PCA): Reduced data dimensions while preserving information. This method was used for identifying geological faults using seismic or magnetic data.
7. Aerial Geophysical Data: Analyzed 7.5-kilometer data to examine the total magnetic field intensity map, determine the location and subsurface status of magnetic bodies, and identify magnetic lineaments and both visible and concealed faults.
8. GIS Layer Evaluation: Assessed and evaluated information layers obtained in the Geographic Information System (GIS).
9. Field Survey: Conducted field visits to familiarize with the study area, correlate available information with field observations, and accurately identify and differentiate lithological units and their relationships, especially fault zones.
Geological investigations, remote sensing, aerial geophysics in the GIS environment, and field operations within the study area revealed that the density map of fault lineaments significantly influences the erosion-deposition trend in the southeastern part of the region, particularly in areas of faulting. Further analysis of regional tectonics indicated that the final thrust faults control the regional tectonics.
Based on geological investigations, remote sensing, aerial geophysics in the Geographic Information System (GIS) environment, and field operations within the study area, it has been determined that the lineament density map significantly influences the trend of land loss in the southeastern part of the region. This map is particularly indicative of substantial variations in fault lineament density, especially in the faulted regions.
After examining the tectonics of the area, it was found that the final emplacement of faults controls the regional tectonics. According to calculations of fault slip potential, in each section of the regional faults, two faults—Shurab and Doldol—have the highest slip potential. In other words, the northeastern segment of the Doldol fault exhibits a higher seismic rate compared to other sections. Remarkably, recent seismic activities in the region have occurred primarily near the major fault zones.
The seismic rate gradually increases toward the northern terminus of the Jombay faults, while conversely, in the southeastern part of the region, the maximum slip potential is observed for the Turkmeni-Arba’id, Kuh-e Pol Khavand, and Baybank faults. Additionally, the Anarak fault experiences an elevated seismic rate toward its northern-southwestern terminus.
The active fault trends in the study area reveal a northwest-southeast pattern, consistent with data obtained from field surveys. Considering the average slip rates of regional faults in recent years and results from previous studies, the northern-southwestern segment of the Anarak fault (from Anarak to the Shurab fault in the Talmasi section) has been identified as an area with the highest likelihood of future sliding. The northern-southwestern half of the study area is associated with the most significant fault slip potential, and tectonic structures in the northwestern-southeastern regions represent the youngest neotectonic activities. Remote sensing data were effectively utilized to display lithological and structural alterations.
In the studied area, which includes 198 lineaments (from remote sensing studies) and 18 digital faults from the geological map of Anarak, with a length of over ten kilometers, as well as 9 probable magnetic faults, the majority of these lineaments are observed in the southwest region. However, these lineaments do not correspond to any fault features on the geological maps. The magnetic lineaments are well-aligned with the structural faults on the geological map, except for lineaments F-586, F-416, F-417, F-698, and F-701, which do not have any equivalent fault representation on the existing maps.
All 198 lineaments require field studies, and most of them are associated with alluvial deposits. These lineaments could potentially represent new geological features. A very high correlation was observed after overlaying the lithology map with the geological map.