Quaternary Journal of Iran

Abstract Introduction

Instrumental records span only a tiny fraction (<10⁷) of the Earth’s climatic history. Therefore, indirect source of climate data must be used. Subfossil pollen and plant macrofossil data derived from sediment profiles can provide quantitative information on past climate. Recognizing the relationship between pollen assemblages and climatic variables and then interpreting fossil pollens base on relationships between them is required to quantitative reconstructions in different regions. Despite pollen-based quantitative reconstruction has begun several decades ago; studies on Iran's past climate have been mainly qualitative and comparative. In this study we used a modern pollen dataset consisting of 119 modern surface samples along significant ecological and climatic gradients over the Zagros Mountains and west of Iran to develop transfer functions and quantitative reconstruction of climatic variables.
 

Materials and methods

In this study collected 59 samples, also 60 samples were collected by wright (1967) were used. Five subsamples of 15*15 cm² within an area of 100 m² were mixed into on sample at each site. Their geographic locations and altitude were determined using GPS. The altitude gradient of these samples is 150 to 4130 m ASL where mean annual temperature ranges from 25.94 to 2.1 C and mean annual precipitation ranges from 203 to 748 mm. Samples were prepared using combination standard techniques of Fægri and Iversen (1975) and Erdtman (1951). A Hund WETZLAR microscope at a magnification of 400 was used for pollens identification and counting. 300 pollen grains were counted for each sample.
A total of 58 pollen taxa were recognized from the surface samples of the 119 study sites. Modern climatic data of 195 meteorological stations of western Iran were used for spatial interpolation. Eight environmental variables were chosen: altitude, mean annual precipitation, mean annual temperature, mean summer temperature, mean winter temperature, mean winter precipitation, mean summer precipitation, mean spring precipitation. Modern Analog Technique (MAT) method was used to reconstruct climatic variables in this study. The MAT is a calibration method for reconstructing a past environmental variable (e.g. temperature) from faunal assosications. It works by finding modern sites with faunal associations close to those in fossil samples. Environmental data from the modern sites are then used to estimate the environment fossil. In order to remove the effects of high collinearity among environmental variables in the process of analyses, we examined the Variance Inflation Factors (VIFs) for each environmental variable. If the VIF value of a variable was larger than 10, the variable was assumed to be almost perfectly correlated with the other variables and it captures little variance. A sediment core that used in this study, (63-J) of Zaribar lake with 25 meters long from the western shore of the lake, were taken by Wright in 1963 and pollinated and published. All radiocarbon dates obtained from Lake Zaribar sediments and published by authors show that this core covers 22500 years before present.
 

Results and discussion

Transfer functions, based on Modern analog technic (MAT), were developed for mean annual temperature (R²=0.6, RMSEP=3.74), mean annual precipitation (R²=0.79, RMSEP=82.74 mm) and mean precipitation of spring season (R²=0.62, RMSEP=21.1 mm). Our results confirm that pollens assemblages can provide reliable estimates of the climatic parameters. The results of quantitative reconstructions of the temperature of the last glaciation of the Earth showed that the air temperature in western Iran was on average 4 to 5 degrees lower than the current period. Also, the mean annual precipitation has been on average 20% less than the current period. At the beginning of the Holocene, the temperature rises significantly, so that the temperature was 1 to 2 degrees higher than the current period. In the Middle Holocene, the temperature dropped by about two degrees, and this situation with low fluctuations has remained almost constant until today. Prediction errors of pollen-climate transfer functions that were calculated in this study is MAP_RMSEP=82.7 mm, ca. 15.1% of the MAP range; MAT_RMSEP=3.74 C, ca. 15.5% of MAT range. A number of factors can influence the prediction error of the calibration dataset such as topographical variation that affected temperature and precipitation variations. Moreover, human impact on vegetation may be another important factor that complicates many pollen-based climate reconstructions. It is important to note that the small number of samples also increased the amount of prediction error.
 

Conclusion

For pollen base quantitative reconstruction in different regions, a reliable number of samples should be collected in different regions, especially drier or wetter regions, as well as colder or warmer regions. Among the climatic variables, the mean annual precipitation has a more significant relationship with the pollen assemblages of the samples and has a better ability for quantitative reconstruction than other variables. Researchs in the Middle and South Zagros shows that during the last glacial period, the vegetation type characterized by high values of chenopodium and Artemisia. This type of vegetation indicates the prevalence of cold and dry weather conditions in this area. The results of quantitative reconstruction of this study showed that in the last glacial period, the air temperature in this region was 4 to 5 degrees colder and the amount of precipitation was 20% less than the current period.

Abstract Introduction
Mud volcanos are one of the strangest and most fascinating geomorphologic phenomena in Iran, mostly in the coastal plains of the Oman Sea and in the Caspian Sea. Mudvolcano, sedimentation is one of the most interesting natural phenomena that spread in the Al-Himalayas, the Pacific and Central Asia in the countries of Pakistan, Azerbaijan, Turkmenistan, Georgia, Iran, Italy, Romania, Japan and Anzadeh, Japan, Mexico and Japan. Oef and Feyz Allahov, 2001).In general, the purpose of this study was to evaluate the effect of tectonics on the current morphology of the studied landforms and then to evaluate and validate the use of morphometric indices by evaluating and adapting the morphotectonic evidence of the area for tectonic analysis of the 5 anticlines. This is a study that can ultimately be used in environmental planning. In the present study, it is attempted to study three main indexes in the field of anticline morphometry, considering that 5 main anticlines of the area have been studied. In this study, the morphometric parameters of the basin and the mountain were used in combination, while for the morphometric evaluation of the mountain, specific parameters and for the morphometric evaluation of the basin there are other parameters.The study area is located in the northern coast of the Oman Sea from the eastern part of the Strait of Hormuz to Bandar Gowater in the Hormozgan Provinces of Wissistan and Baluchistan in the geographical range of 25 14 57 to 00 58 east longitude and 38 25 to 00 26 north latitude .
 
2-Materials and methods
The data used in this study were in addition to documentary data, 1: 250000 and 1: 100,000 digital geological maps, DEM30m digital elevation model data, Landsat satellite imagery data, Google earth imagery, and Mudvolcano morphometric data collected during extensive fieldwork. The tectonic activity domain analysis tool has been used to calculate the morphometric indices of the anticline including the three main parameters of the triangular procedures, the wine valleys and the sinusitis of the anticline front. In order to calculate the morphotectonic status of the area, the relevant parameters were first calculated separately in the North and South Duvial, which consist of triangular procedures, canyon valleys, and mountain front sinusitis.
 
3-Results and discussion
Triangular procedures are special shapes that occur on mountain foreheads, fault cliffs, and folding edges Are formed. The occurrence of these phenomena is the result of active tectonics in an area that occurs as uplift and uplift of geological layers and fold formation. If the eruption rate is higher than the water erosion rate, the phenomena are triangular to polymorphic, separated by waterways. The higher the tectonic uplift, the more triangular the procedures will be. In this study, a total of 251 triplicate procedures were identified on 5 antecedents studied, of which 88 were in antecedent 1, 32 measured.
 
4-Conclusion
The results of field impressions described as tectonic forms adjacent to the main faults indicate high tectonic activity in the area, which derives from quaternary movements of the major faults. Also the tectonic dynamics of the region with direct influence on the morphology of the region in satellite images is shown as tilt and cuts along the channels. In general, the results show that tectonic activity is higher in the southern edges of the anticlines. These evidences showed that the highest accumulation of morphotectonic evidence such as displacement of formations, stepping faults and rivers diversion in and around the anticline was observed, suggesting more tectonic activity in the area. In general, the results of the indexes and evidences examined indicate the dominance of the tectonic activity at the regional level and since the accumulation of the studied in this area also indicates the tectonic effect of the area on their occurrence. The study area is affected by compressive forces on the one hand with compressive zone due to subduction of the Oman Oceanic crust below Makran area and on the other hand the area of ​​contact of Makran zone with Zagros zone is rapid sedimentation of Quaternary sediments and trapping of methane gas in layers. The deep clay and fine sediments of trap anticlines caused by the compressive forces of the tectonics have caused mudflows and gases due to this subduction to the studied fault system. So that its faulting process is associated with the birth of new and young Mud volcanoes.

Abstract Introduction
Calcareous soils are widely distributed in arid and semi-arid regions of the world and the presence of carbonates in the soils affects both physicochemical properties and the pedogenic evolution. In addition, soil carbon plays a critical role in the global carbon cycle, and pedogenic carbonates are an important sink for atmospheric carbon. Pedogenic carbonates are also the proxy of past climatic variations which are frequently used in geomorphological and paleoclimatological studies. The aim of this paper was to provide a comprehensive review for formation and accumulation of the pedogenic carbonates in arid and semi-arid regions.
 
Methodology
We reviewed the published studies on carbonates formation and accumulation in the soils. Dynamic and processes of carbonate accumulation were explained. Accordin to the literatures, 15 conceptual modeles and 15 numerical and computer modeles of pedogenic carbonares formation were identified.
    
Results
Numerous models and classification systems have been proposed for the formation and evolution of pedogenic carbonates, including conceptual models and numerical and computer models. Indeed, conceptual models are qualitative descriptions of events and changes in the systems, while numerical models are quantitative descriptions of events and processes and can be very challenging due to the very complex nature of the soil system.
Generally, conceptual models of calcrete development can be divided into two categories of conceptual models without considering landscape processes (pedon scale models) and conceptual models with considering landscape processes (landscape scale models). At the pedon scale, three types of conceptual models have been defined for the development of calcic horizons: (1) the model of progressive changes, (2) the model of in-situ alteration and (3) the rhizogenic model. On the other hand, five conceptual models have been proposed for the evolution of calcareous soils with considering the processes of erosion, sedimentation and degradation of calcretes.
Numerical and computer models of carbonate accumulation in soils can be used to study the influences of late Quaternary climatic changes on the carbonate accumulation in soils. In general, mathematical, compartment and hydrological models have applied in the modeling of calcite accumulation in soils. However, although theses models may be internally correct, they may represent incomplete phenomena due to the lack of enough knowledge of the system or incorrect assumptions.
 
Discussion
In the conceptual models, the process of carbonate formation is considered as crystallization of calcite from soil solution, calcification of plant tissue or recrystallization of calcite crystals in the parent rock. Because conceptual models study the evolution of carbonates over time, chronosequences (e.g. the geomorphic surfaces of alluvial fans) have been used as a tool in the development of these models. Overall, despite the widespread application of conceptual models at the pedon scale by geoscientists, there are some disadvantages:
 
(1) Many of these models do not consider the role of landscape processes such as erosion and sedimentation in the process of carbonate accumulation.
(2) Conceptual models assume the development calcic horizons as evolution from one stage to another in the range of 4 to 8 major evolutionary stages with a linear trend. However, micromorphic analyses have been demonstrated the polygenetic and nonlinear nature of mature calcretes.
(3) Many conceptual models have assumptions that may not be appropriate for many parts of the world. Some models consider the presence of interbedded limestone, the presence of clayey sediments or the presence of a natric horizon in the early stages of development. Therefore, these models may have only regional implications.
(4) In some models, different formation mechanisms are suggested for similar phenomena. For example the evolution of a laminar layer on the surface of mature calcretes are attributed to the accumulation of moisture and plants roots or the accumulation of aeolian silt by lichens.
(5) Recent studies and the application of micromorphological techniques have shown that conceptual models are over simplifications and do not take into account many processes.
Despite the issues of conceptual models, these models are still valid and are widely used to describe the morphology of pedogenic carbonates due to their simplicity of application and high efficiency.
Computer models have been developed since the early and mid-1980s and have been used primarily to study the effect of Quaternary climatic indicators on the accumulation of carbonates in the soil. Initially, models were developed with an emphasis on physical and chemical processes of calcite deposition in soils and soil system was considered only in the CaCO₃-H₂O-CO₂ system without considering the role of biochemical reactions. Recently, biological factors and the effect of plant roots as well as weathering of aluminosilicates on calcite formation have also been considered.
In addition, the assumptions of these modeles to simplify calculations which have a great impact on the results:
(1) Rainfall infiltrates into the soil fully and in one dimension and there is no horizontal flow or surface runoff.
(2) Soil temperature is assumed to be constant and seasonal variations are not considered. In addition, the use of modern temperature as a long-term variable is incorrect due to Quaternary climatic changes.
(3) Water movement through the pedon is assumed as a saturated flow and unsaturated flow, which is important in coarse textured and dry soils, is ignored. In addition, the effects of matric potential changes and upward movement of water in the soil by plant roots, are not considered.
(4) Changes in the amount of hydraulic conductivity and soil water holding capacity during the accumulation of carbonates in soils are of important. For example, plugging the soil matrix with carbonates increases the water holding capacity of soils. Furthermore, the formation of carbonate nodules causes changes in the physical properties of the soil, as well as changes in the path and velocity of water in the soil and may result in the preferential dissolution of calcite.
(5) In many numerical models, carbonate transport is assumed to be a mass flow and the diffusion of carbonates in the soil is ignored.
(6) The origin of calcium ions in many models is considered as a constant rate of dust input and/or a constant concentration of calcium ions in rainwater, which is not reasonable in the long-term due to late Quaternary climate shifts.
(7) The amount of present rainfall in many models is considered as long term precipitation, which is not a correct assumption owing to climatic change in the Quaternary. In addition, the models are not able to estimate the effects of rainstorms on the formation of carbonates in arid regions. Studies have shown that heavy rainfalls in arid lands can be very effective in formation of calcic horizons.
(8) Information on the partial pressure of carbon dioxide in soils is in many cases inaccurate and also the average annual application of this index is not correct due to seasonal fluctuations and ecological changes during the Quaternary.
(9) Many models consider only calcite mineral as soil carbonate mineral and ignore other minerals, especially dolomite. Studies have proven that the secondary calcite that precipitates from the soil solution is richer in magnesium than pure calcite. The mineralogical analysis of pedogenic carbonates of soils demonstrated the occurrence of low-Mg calcite.
(10) Numerical models assume that the processes of dissolution and deposition of calcite occur instantaneously and very rapid relative to water movement in soil, which may not be a correct assumption in all soils.
(11) Many models do not consider the role of erosion and sedimentation processes in carbonate accumulation and assume that soil thickness is constant during the evolution.
 
Conclusion
Despite the problems of both conceptual numerical models, they are very valuable tools for testing past climatic scenarios on soil development.
Finally, a review of conceptual models shows that these models are mainly based on the soils of the arid regions of the southwestern United States, the Mediterranean, and Australia. Although calcareous soils cover most of Iranian lands, there is no modeling for carbonate accumulation processes in these soils. Therefore, there is a very strong potential to test the above models and provide new conceptual models based on the conditions of Iranian soils.

Abstract Introduction
The western foothills of the Zagros Mountains as a border area located between highlands of Iran and Mesopotamian lowlands, considered as an important archaeological study area. this area as a contact zone not only helping in better understand of the cultures located between this two different landscape of Near East (Mesopotamian lowlands and Zagros highlands), but by studying their formation process and the issues influenced it, the regional and interregional regional communication pathways could be synthesis more obvious. In this study, based on landscape archaeology and analytic methods and using the Pierson methods, the proportion of different variance related to formation of archaeological sites were analyzed. At the end we identified 3 settlement patterns and we find that the 3 key issues of access to water sources, the kind of lands and access to the roads are the main issues that influenced the formation of sites. 
 
Materials and Methods
The data of this research were collected based on archaeological survey in 2015, and in the next step other information was collected by documentary method. This research is a fundamental study and in terms of method is part of historical-analytical research. The authors by using Pearson’s correlation statistical method and ecological approach in archeology, will try to evaluate the role of various factors in locating and distribution of the ancient settlements of Sar Pol-e Zahab area. This study tries to answer the question that how were the settlement patterns of Sar Pol-e Zahab region as the strategic region between the Iranian heights and the land of Mesopotamia in the fourth and early third millennium BC and what variables were the affecting factors in locating of these settlements?
 
Results and discussion
In our survey of mention plains, it was identified totally 14 sites of the fourth millennium and early third millennium BC. that their cultural materials indicate their belonging to the Uruk and Jamdat Nasr cultures. These include 13 sites in Zahab plain and one in Beshiwa plain, but no site of ​​the mention periods have been identified from the survey of Patagh and Qaleh Shahin plains.
We used the Cluster analysis to know the pattern of settlements of the fourth and early third millennium BC and understanding and the better analyze of distribution of archaeological sites of this period and to find the relationship between the distribution patterns of the settlements and environmental variables. This means that environmental factors such as altitude, distance from water sources, size and direction of slope and the type of modern vegetation was considered as an independent variable and the dimension of ​​ancient sites was considered as a dependent variable and the relationship between the nature of the sites and various factors has been measured by using of Pearson’s correlation method.
Based on this research, three types of settlement patterns were identified and it was found that three factors of access to permanent water resources, type of land use (soil type) and accessing to main roads had the main impact on the formation of settlements in the mentioned region.
 
Settlement pattern A
Settlement pattern A, which has the largest number of sites, includes 8 sites. altitude level for these sites is between 510-630 meters. The sites are located between 50 to 1500 meters from permanent water sources and have a size between 7350-18020 square meters. All these sites are located in suitable lands for agriculture. The distance between this group of sites is between 30 to 4170 meters.
 
Settlement pattern B
In this pattern, there are three sites larger than two hectares called Maikhan, Tape Kaleg and Sarab Zahab-e Ghaderi, and this case is probably more related to proximity to water sources and locating along communication routes. These sites with dimensions between 23,100 to 24,000 square meters are located at an altitude of 530 to 570 meters above sea level. The mentioned sites are located at a distance of 5 to 810 meters from the modern main water sources. These sites are located in land with agricultural use and a slope of 4%. Regarding to the location of these sites in the landscape of the region, their large size and proximity to the communication route it seems that comparing to the other groups, this group are probably strategic and important sites and due to the proximity to the main communication routes It is possible that their inhabitants are engaged in regional trade in addition to agriculture and animal husbandry.
 
Settlement pattern C
The sites that are located in this cluster and settlement pattern are three sites of Shahouk, Sarab-e Kuwang 1 and Sarab-e Kuwang 2. Altitude of this group of sites is between 520-525 meters and they are located at a distance of 20-75 meters from permanent water sources. These sites have size ​​about 2770 to 4120 square meters and comparing to the other sites are located in a cluster due to their small size. In terms of land usage, the mentioned sites are mostly located in agricultural lands and the only difference between these sites and group A is their very small size and their location on the border of plain and adjacent to water resources (springs). Regarding to their location and their low dimension, as well as their small size of their deposits, it seems that these sites are probably seasonal sites. These sites are formed at a closer distance to the hills and foothills than other groups, which somehow indicates exploitation of heights. The small size of the sites and their distribution based on a linear pattern along water resources that are also located in low-fertile lands and have good access to pastures, may be a clue of livestock livelihood in this area.
 
Conclusion
As the clustering of the sites shows, the pattern of spatial distribution of the settlements of the fourth and early third millennium BC in the Sar Pol-e Zahab area is divers. The reason for this diversity is largely due to environmental and natural factors. The distribution of settlements in this region is more affected by environmental factors such as water and fertility soil resources. On the other hand, these sources are not the only effective factors, but probably another factor such as communication routes has been effective in this distribution. In the analysis of the patterns of the sites of the Uruk period in Sar Pol-e Zahab area, three settlement patterns were identified that according to the location and landscape of the region, the sites of each cluster probably have different nature and functions. Environmental conditions required that in addition to the seasonal function of the sites in terms of agricultural and livestock livelihoods, due to the passing of one of the most important trade routes of the ancient world, the inhabitants of some settlements in this area could play a role in trade.
Existence of permanent river Dalashir in Zahab plain, as well as several permanent and full of water mirages including Sarab-e Qara-Bolagh, Sarab-e Seyed Sadegh springs and to some extent Zahab springs with suitable slope of plain and agricultural fertility suitable soil formed Suitable conditions, as well as it is now, for formation of settlements in the region Based on agriculture which they have been able to organize water-based agriculture in the lands around the settlements by utilizing the water of mirages and springs. If this perception be correct, the possibility of irrigated cultivation can be mentioned as the most important factor in the formation of these settlements in Zahab plain. This argument is reinforced by the density of settlements in the fourth millennium BC of Zahab plain and the lack of settlements of this period in Qaleh Shahin plain and the existence of only one site in Beshiva plain.

Abstract Abstract
1-introduction
It is very important to study the quality of groundwater and the zoning of qualitative parameters for different uses. In some cases, this related to composition and Quaternary deposits.
Groundwater is considered as an important source of water resources due to its low pollution potential as well as its high storage capacity compared to surface water. The chemical composition of water-soluble ions is affected by various reactions that occur between water and aquifers. Numerous factors, such as poor recharge and nutrition, reactions between water and rock, such as the dissolution of evaporative rocks and the phenomenon of cation exchange from groundwater, mixing of waters such as the infiltration of saline seawater into coastal aquifers, agricultural return water can control the salinity of groundwater. This study aims to evaluate the quality of groundwater in Quaternary sediments of Jovin plain located in northeastern Iran, which includes the study of spatial changes in groundwater quality in different sectors and determining the factors affecting it.
2- Materials and methods
In this study, a combination of statistical methods such as cluster analysis and correlation coefficients and hydrochemical methods such as ionic ratios and compound diagrams have been used to evaluate the chemical quality of groundwater. In this plain, three large zones can be seen as follows from the south to the north: A. Coarse-grained alluvial fans, the materials of these deposits are mostly gravel and sand, but they also contain coarse-grained and fine-grained layers and lenses. The physical properties of this unit, such as porosity, skewness and lack of cement, rate of weathering, are similar to very coarse-grained alluvial units. B. The young alluvial fan structures, this unit are mostly made of fine-grained materials such as sand, silt, along with horizons of gravel. They are a concentrated location for agriculture activities. From a morphological point of view, the aforementioned fan structures have not yet lost their morphology. Therefore, due to the lack of erosion and erosion grooves, the age of young alluvium has been attributed to the Holocene. C. Flood zone deposits in the northern part of the study area, two zones throughout, have formed parallel to the heights of Mount Jovin. To check the chemical quality of groundwater in Jovin plain, 29 water samples were collected from agricultural wells located in plain. The samples were then analyzed to measure cations (Na +, Mg2 +, Ca2 + and anion (SO42-, HCO3-, Cl-) and other chemical parameters including EC, TDS, TH and pH.
 
 
3-Result and discussion
Based on the results of cluster analysis, the aquifer can be divided into 4 zones, each group having a different chemical composition. According to the matching of the information layers (grouping the groundwater quality with the quaternary outcrops of the region), the wells that make up zone one in terms of water quality are geologically in the structural area of ​​large foothill alluvial alluvium, zone wells. 2 In young alluvial fan structures, zone 3 and 4 wells are located in floodplain deposits. The type of water in the direction of groundwater movement varies from the southern heights of the plain to the north of the plain to the Kal-Shoor River (from zone 1 to zone 4) from sodium bicarbonate to sodium sulfate and finally to sodium chloride.
4-Conclusion
This process was based on the matching of the sodium cation diagram with the sulfate and chloride anions. In the study of ionic ratios, the origin of sodium is from the weathering of plagioclase-albite and ion exchange, magnesium from upstream granites, calcium due to ion exchange with quaternary sediments of the aquifer. The concentration of groundwater-soluble ions increases from the first group to the fourth group. In the first and second groups, the water type is bicarbonate-sodic, in the third group, sulfate-sodic and finally, in the fourth group, the water type is chloride-sodium. This indicates the series of anionic evolution and from the south to the north of the plain in the direction of groundwater flow. The high correlation between chlorine and sodium (R² = 0.93) indicates the presence of a linear relationship between these elements and the role of the dissolution of halite in the chemical composition of groundwater in the region. However, the unequal concentration of chlorine and sodium in the analyzed samples of Jovin aquifer indicates the existence of another source (albite degradation or ion exchange) for these two ions and the Na / Cl ion ratio in all samples is more than 0.5, which also emphasizes this point. By examining the concentration of groundwater aqueous solution of TDS in groups 1 and 2, it is below 500 mg / l and indicates the weathering of silicates. Groups 3 and 4, located at the low stream of the plain, are above 500 mg / l, indicating the weathering of carbonates.

Abstract 1- Introduction: Geomorphic investigation is a powerful tool for studies of active tectonics in active regions. Active faults and folds commonly have topography that can assist in identifying different geomorphic or structural segments along a structure, and estimating the potentially most active segments. In tectonically active regions, drainage networks and topographic features can be used as a way to quantitatively characterize the interaction between tectonics and surface process providing a basis for modeling landscape evolution. The study area (north and northwest of Damghan) is located in northern Iran and in the eastern part of the Alborz range. The Alborz mountains form a sinuous range over 1,200 km long, separating the high plateau of central Iran from the South Caspian basin, which lies near sea level. The active tectonics of this region appears to accommodate N–S regional shortening by partitioning onto separate thrust and left-lateral strike-slip faults. In this study, neotectonic activity of the north and northwest of Damghan, as a part of the Alborz tectonic-sedimentary unit including Astaneh fault, Damghan fault, North Damghan fault and Attari fault and as the main area destructed during the Qumes earthquake (856 A.D.), has been studied. The 856 A.D. Qumis earthquake (M 7.9) is the most destructive earthquake to have occurred in Iran, killing more than 200,000 people and destroying the cities of Damghan and the old Parthian capital of Shahr-i Qumis (Hecatompylos).
2- Methodology: Morphotectonic indices are useful in evaluating the tectonic activity of regions. Morphotectonic analysis using geomorphic indices has been developed as a basic reconnaissance tool in order to identify areas experiencing rapid tectonic deformation or estimate relative variations of tectonic activity in a specific area. In this research, neotectonic activity evaluation of the region was done mainly based on three important morphotectonic indices: Stream Length-gradient, Mountain-front Sinuosity, and Drainage Density. Using digital topographic data, digital elevation model (DEM), aerial photographs and geological maps, these indices were computed for different parts of the study area.
3- Results and Discussion: The results obtained were shown as digital maps provided using ArcGIS (10.7) software. Maps showing the spatial variation of different studied indices across the area were provided and interpreted in this study. As a result, it is concluded that parts of the northern Damghan area mainly with similar strike to the Damghan fault, North Damghan fault and Astaneh fault show more tectonic activities in comparison to the adjacent areas. In addition, the high correlation between the trend of anomalies and the strikes of faults of the area demonstrates the influence of faulting in forming these geomorphologic features. A comparison between the resulted maps and the general structural map of the area indicates that the approximate trends of abrupt changes in drainage density values, acceptably correlate with the general trends of the major faults and large-scale folds of the area.
4- Conclusions: The results obtained indicate that the analysis of morphometric indices, as well as the quantitative analysis of stream patterns, can be very useful for evaluation of the relative intensity of neotectonic activity of regions especially when the other techniques could not be employed for recognition and assessment of the active structures.

Abstract The northern fringes of the Iranian Central Desert (NICD) is a long corridor created due to the proximity of the Alborz Mountains to the north and the Central Desert to the south. For the first time, one of the present authors (HVN) highlighted the importance of the NICD as one of the routes for the dispersal of human populations from Africa to East Asia during Pleistocene epoch. In recent years, huge surface scatters of lithic artifacts have been found at open-air Paleolithic sites of the region such as Soufi Abad, Delazian, Mirak, Chah-e Jam, and Zaviyeh, with Mirak being the only excavated site. Sedimentological analysis in Mirak indicates that due to climatic fluctuations, the NICD had been frequently visited by human populations through millennia, especially during MIS 3. According to these results, the presence of cultural Pleistocene deposits could be expected for the other Paleolithic sites mentioned, the identification of which is difficult due to some complications. For instance, among other factors, the alluvial fans of the southern Alborz and the infiltration of their sediments to the region has caused the covering of Pleistocene deposits by recent Holocene ones and the Pleistocene outcrops are only seen in some spots across the region. Thus, it could be assumed that there are more Paleolithic sites across the NICD which are buried beneath newer sediments, agricultural lands, and urban facilities. This paper is an attempt to study the Quaternary surface deposits in the region and to assess their relation to the presence or absence of Paleolithic relics. In doing so, two questions arise, as the following:

To what extent has the presence of Paleolithic human population been influenced by the environmental featues across the region?
Which types of surface deposits are more talented for possessing the evidence of Paleolithic relics across the NICD?

2. Materials and Methods
The NICD extends along Semnan to Markazi Provinces in east-west axis. The Paleolithic sites of the region, including Zaviyeh, Masileh, Moghanak and Ochounak, Soufi Abad, Delazian, Mirak and Chah-e Jam are investigated from sedimentological aspects. An integral part of the present study is the comparative sedimentological analysis of the landscapes which requires frequent field visits. Field activities include pedestrian surveys and direct observations of sedimentary features of the Paleolithic landscapes and also, the landscapes with no reported Paleolithic evidence. The geomorphological features of the region are including vast pediplains, rolling hills, nebkha and non-nebkha mounds, river terraces and seasonal canal beds, and sections created by civil construction projects. The photos were taken in order to compare the features to each other and to the Geological maps of the region. Duringin conducting the comparative analysis, in addition to using geological maps and satellite images, the results of other laboratory and field studies in the region were also used (library research method). Finally, based on the information collected, some pedestrian surface surveys were designed in the NICD, which resulted in the discovery of two open-air Paleolithic landscapes, namely, Shour-e Qazi and Sar Darreh.
3. Results and Discussion
As mentioned above, the sediments of newer periods could usually cover and hide the Paleolithic remains and make them inaccessible. Thus, before choosing the area of study, the type of sedimentary environments should be considered in terms of the visibility of cultural remains. In general, sedimentary environments are divided into three groups in terms of erosion and sedimentation, as the following: erosional environments, accretion environments, and balanced environments. In erosional environments, erosion rate is heavier than sedimentation. In water erosion environments (e.g., erosional pediments), due to the relatively high energy, the possibility of moving, transporting and washing the archaeological material is usually high. Thus, it is better such environments are not considered a priority in pedestrian surveys; albeit in such environments, the sections and walls of water canals may sometimes expose the traces of archaeological material. On the contrary, in aeolian erosional environments, due to the lesser energy than water, only fine-grained particles are usually transported and larger rubbles and pieces of rocks (including stone artifacts) remain in the form of desert pavement. Such environments are suitable for pedestrian surveys; the examples of which could be seen in Delazian, Mirak, Soufi Abad and Chah-e Jam.
 In accretion environments (e.g., modern floodplains), the sedimentation rate is higher than erosion, which causes the burial of cultural artifacts. As a result, it is better not to prioritize such depositional environments. In the so-called “balanced environments” (e.g., interior of cave spaces, or playas), the rates of sedimentation and erosion are rather equal. In such instances, the archaeological remains are likely to remain visible for a protracted period of time without being buried. Such environments are also of significance for pedestrian surveys.
4. Conclusion
In response to the first question, it seems the latitudinal diversity in topography and ecosystems in the region, the availability of freshwater in the form of permanent or temporary water bodies, the possibility of longitudinal movement due to the similarity of environments in the east-west axis, as well as the advantages of open landscapes in the region are among the most important factors that played roles in attracting human populations to the NICD.
 In responding the second question, one could look for two types of environments. The wind-made desert pavements are one of those two, which bear surface lithic artifact scatters mixing with natural pebbles and rubbles. In such environments, some nebkha mounds are sometimes seen which could help to hold archaeological deposits against the wind power, like what is the case for Mirak. The second environments which are of significance for pedestrian survey are the dorsal ends of alluvial fans and the pediments located upstream of the local streams and in the upper margins of the playas; since in one hand, such zones have been largely overlooked for residential and agricultural uses due to their relative dryness and the higher degree of soil salinity, and on the other hand, due to the decrease in slope, the energy of water is reduced in such zones and as a result, the chances of erosion in archaeological deposits and the transportation of lithic artifacts are less here.