نشریه کواترنری ایران
پیاپی 13 (بهار 1397)

Today, the Environmental studies on the quaternary regions of sediment are becoming increasingly for various purposes. In this study first Lithological units including the Ophiolite zone of Nosrat-Abad were separated by Remote Sensing. Then, using geochemical data of drainage sediments (350 specimen), in order to better identify the contaminated or exposed areas of heavy metals elements of Nickel , Lead, Zinc, Copper and Molybdenum beginning to preparing maps distribution of pollution index (Igeo) and contamination factor (CF). Also, the method of correlation coefficient and cluster analysis, which is a multivariate statistical method, was used in this study for the statistical analysis of the elements. For this purpose, first developed the appropriate change model theory for each of the calculated indices, the Kriging method was used. In order to identify pollution regions on a local scale, especially high and low density, the inverse weighting method of IDW distance is more appropriate. For each of the indices calculated in this study, the inverse distance method (IDW) was used in the GIS environment and the statistical parameters of SPSS software were used. The results showed that the region of ​​Nosrat-Abad has a high contamination in the presence of nickel in the southeast, and the lead element also has a moderate pollution in the south. As a result of separation the Ophiolite units of the region were identified by Remote Sensing of the rocks with the nature Basic (Gabbros and Basalts) as the source and inclusive Ni and Cu Elements Available in the region.

The ecology of paleo-environments can provide researchers with valuable information about climate events such as cycles of drought and periods of more mesic conditions. The results of such investigations can be a significant contribution to investigation of future environmental conditions. This research was initially conducted with the aim of monitoring current drought conditions, and revealing long-term and future droughts of northwestern Iran by calculating and modeling the standardized precipitation evapotranspiration index (SPEI). In order to assess paleoclimate conditions, the Macrophysical Climatic Model (MCM) based upon current conditions, data from synoptic, climatologic, and rain gauge stations during 1950-2016, and future climate conditions derived from the Geophysical Fluid Dynamics Model (GFDL, CM2.1) were used. To verify the reconstructed data of the past 15,000 years and modeled future data for next 83 years, two statistics, the determination coefficient (R2) and root mean square error (RMSE) were used, and eventually the standardized precipitation-evapotranspiration (SPEI) index for Drought monitoring was applied for long, current and future periods.   Verification of reconstructed paleoclimate temperature and precipitation and future seasonal rainfall data at Lake Neor using root mean square and error coefficients and the determination coefficient, showed that the modeled data results had significant accuracy. Initially for this study, past climatic conditions and the long-standing weather conditions of the Neor Lake in the northwest of Iran for a period of 15000 years B.P. were reconstructed using the Macrophysical Climate Model (MCM). Then present drought conditions were investigated using the observed data of the past 67 years (1960-2016). Then future weather conditions for the period 2018 to 2100 under the A1B emission scenario, which is based on the model of the GFDL, CM2.1 dynamic model, was reconstructed. Then future climatic conditions were illustrated using current data (1950-2016) from synoptic stations, climatology and rain gauges. Finally, the droughts and wet seasons of Neor Lake past, current and the future were calculated using the standardized precipitation-evapotranspiration (SPEI) index. Reconstructed paleo precipitation data showed that the Lake Neor had a completely different rainfall pattern in spring compared to winter, fall, and summer. Spring rainfall was greater than that of winter between 15000-12000, and from 8700 to 4000 years B.P., overall precipitation was declining. Thereafter, unlike other seasons, spring rainfall at Lake Neor shows a relative increase up to the present. With increasing spring precipitation, increased vegetation cover has occurred in the Neor region since the mid-Holocene, while the trend of spring droughts appears to be due to increasing temperatures. Other results of this study indicate that the paleo-rainfall regime of about 15,000 years B.P. in the Neor region is not fully consistent with the results those of multiproxy data extracted from sediment cores, although the occurrence of events such as Younger Drays is in agreement with existing studies. The survey of the SPEI index of Lake Neor led to the identification of seven water phases. During the first three hydrologic phases, which lasted from 15000 to 12000 years B.P., the average rainfall (573.09 mm) of Lake Neor was higher than the long-term average of the region during past 15000 years B.P. This period probably corresponds to the recent glacial period at Lake Neor. Since 12,000 years B.P., despite considerable fluctuation in the modeled rainfall, the average precipitation of each hydrologic phase has declined relative to the long-term average. By analyzing the temperature regenerated for the hydrologic phases of Lake Neor, we  can see evidence of the long-term increase in  temperature. In the first four hydrologic phases, from 15,000 to 11,000 years B.P., there is a  steady decrease in temperature compared to the long-term average of 8.38 ° C. Since the fifth hydrologic phase 11,000 years B.P., it has been rising, and in the sixth and seventh hydrologic phases, after 8700 years B.P., the average temperature has been higher than the long-term average. The results of the current investigation has shown that the long-term climate of the Lake Neor region, although the frequency of dry cycles in the summer is more than in the winter, the intensity of winter droughts (SPEI drought Index) was greater. Demonstrating the increasing intensity of drought periods in the cold season as an important result of this study. It shows that cold periods in the study area are getting warmer and with decreasing rainfall and increasing temperature, evapotranspiration in the area has increased as well. This may have some relationship to the increased frequency of dust events. Comparison of the long-term, current and future drought index shows that although Lake Neor experienced decreasing dry periods and an increase in longer wet periods during warm seasons in the past, in the future, the warm season of the year shows the dramatic rise in dry periods and a decrease in the wet episodes. This will be a critical factor for the survival and growth of plants, such as oak trees, that need moisture in the warm season.

Qorveh-Bijar area is east of Kurdistan province, located in northern part of Sanandaj-Sirjan zone in northwest of Iran. Quaternary volcanic rocks composition include of Basanite-tephrite to olivine basalt, basalt and trachyte. These rocks main phenocrysts are clinopyroxene, olivine and plagioclase. Plagioclase, biotite, hornblende and apatite are the main phase of mesostase. The EPMA results show that the plagioclases are show delicate zoning and have oligoclase to labradorite composition. Amphibole have magnesian-hastingsite composition and clinopyroxene with magnesium-calcium element ploted in diopside field. Olivine show the chrysolite type near to the magnesium pole, Mica is a phlogopite type and opaqius minerals shown the titano-magnetite composition. Based on the composition of amphibole and biotite, the magma have been the high rate of oxygen fugacity during the crystallization. According to the chemical composition of clinopyroxene, the basaltic rocks show the alkaline nature and was formed in continental within plate with extensional conditions. The magma temperature during the clinopyroxene crystallization is between 1150 to 1200°C and in the 5 to 8 kb pressures. Also the reange of magma temperature during the plagioclases crystallization have been 650 to 900°C.

 Glacial evidence is one of the most prominent legends of the Quaternary climate. Quaternary climate changes have played a special role in the form of the current landforms of Iran. The change in the domain of the ELA is the result of these changes. Changes of the ELA are permanent boundaries throughout the quaternary as the boundary of changes in shaping domains in Iran. Among the glacial evidence, cirques are very important because of the ability to convert to quantitative data. The cirques are a reflection of topography, geology, type and duration of glacier effects. Among the basic issues in glacial studies are the ELA and the water and ice equilibrium line. ELA in Porter's idea is a line in which the expansion of the glacier by accumulation is superior to ice melting over the course of the harvest. The Northern geomorphic unit is said to be part of the continuous integrated mountain range of the southern and western parts of the Caspian Sea, which, like the inert barrier, separated the Caspian Sea from the interior of the country. The first step to estimating the ELA, identifying glacial evidence such as the cirque. To track the cirques of the area were used topographic maps with scale 1: 50000 and, the curvy lines, the 30 * 30 digital elevation model, form of glacial evidence and  the ARC GIS and Global mapper softwares. Due to the wide area of the study area, the estimation of ELA was integrated with the problem, in order to solve this problem, first the ELA was calculated in the water basins of this unit. In this research, using topographic maps with scale 1: 50000, 2055 glacial cirques were identified in the study area. For estimating the ELA were used Wright, cirque-floor altitude, Terminus-to-Head Altitude Ratio (of Wright and Porter), and altitude ratio's methods in different geographical directions. Due to the effect of slope direction of the formation of cirques in the temperate regions, can not trust the estimated ELA without regard to direction. In Wright's method, ELA is determined using determining the location of the cirques and passing 60% of the line (Parizi et al, 2013: 117). For Porter, the glacier fills the cirque when the ELA is not much higher than the average cirque-floor height. This method is used to obtain the previous ELA (Ghorbani et al, 2016: 4). Using the terminus-to- head wall ratio approach, the equilibrium line altitude (ELA) and the THAR ratio are obtained. With THAR method, the best result is obtained for small and symmetrical glaciers with normal distribution of areas and heights (Yamani et al, 2013: 7). The mountainous regions of the northern geomorphic unit are located in the central part, and this area has better conditions for the formation of the cirques and the glacier. This unit is divided into sub-basins of Talesh-Anzali, Sefidrud-Haraz, Haraz-Gharehsu, Gharehsu -Gorganrud, northern parts of the Central Desert.In this unit, 2055 cirques was identified. The terrains’ direction are western-eastern and the cirques are formed on the northern-southern slopes, But the Talesh- Anzali Basin is an exception and its terrains’ direction is Northern-Southern, where the east-west slopes are more favorable for glacial activities. In this basin, 84 cirques were identified. The abundance of cirques in the Sefidrud-Haraz is 361, the Haraz- Gharehsu is 661, Gharehsu-Gorganrud is 103, and the Central Desert is 846. After removing pseudo-cirques, 1948 cirques remained with this unit and the percentage of remaining cirques was estimated. In the northern geomorphic unit from west to east, due to the reduction of precipitation and relative humidity, ELA has decreased. In ​​Sefidrud-Haraz basin (the westernmost basin) of this unit, ELA is more than 2980 m and is estimated to be 2460 m in Gharehsu-Gorganrud basin (the easternmost basin), with an altitude difference of 520 m. There are 2 exceptions in the basins of this unit; one is the Talesh-Anzali basin that its terrains are in the North-South direction and has the lowest ELA (2033 m) throughout Iran due to local conditions. Another is the central desert basin (Northern part), whose slopes are directed toward the south (southern Alborz). The findings show that the ELA is estimated in different directions in the basins by using the Porter's cirque-floor altitude and altitude ratio's methods than other methods is most receptive. According to the extent of Northern unit in the longitudinal geographic, the estimated ELA is decreased with reduced precipitation and relative humidity from west to east. The highest ELA in this unit was 2987 m in the Sefidrud-Haraz basin and the lowest elevation were 2460 m in Gharehsu-Gorganrud basin. Talesh-Anzali basin with northern-southern Talesh Mountains are an important exception that has the lowest ELA in water basins (2033 m). The average ELA is estimated at 2589 meters.

Jahangir Site has been located at, 25-kilometer distance from the southwest of Eyvan city in Ilam province, and on the northern margin of Kangir River. The first archaeological studies in the area were conducted by VandenBerghe in 1970 . With the construction of Kangir dam for the prevention of water flow into Iraq, the ancient sites existing on its margin were put at risk. For this reason, the conduct of a rescue excavation was placed on the agenda of Iranian Center Archaeological Research. After the filling of the dam in winter 2015, a number of sites were immersed in water, and only Jahangir remained. some precious architectural and objects were found for the first time in Iran's Sassanid era by excavations in Jahangir. The analysis of these findings can provide the response for one of the important research questions and gaps pertaining to the transition period of the Sassanid era to Islam in western Iran. In addition to political factors, geography has been an effective and active contributor to the organization and decline in this site. This area is a part of Zagros folded zone that was studied in terms of the geological variables, including lithology, climatology, erosion, sedimentology, hydrology, and seismological investigation based on field evidence and observations, geological maps and resources, and by using the results of previous geological studies. The present paper is a report from the general interpretation of a site for archaeological purposes and for the development of its conservation plans. Based on the total of data and the interpretation done on the related studies presented in different parts of the current research, it is possible to reach a comprehensive analysis of this ancient site : The ancient structure is located on the second generation quaternary alluvium, which are the young fluvial terraces and alluvial fans. The quaternary sediments of the valley generally originate from the erosion of the rock of adjacent altitudes and older sediments of the valley basin, which have been transported and eventually deposited during various erosion periods. From the petrologic point of view, the area can be considered as a perfectly favorable area for erosion because its constituent formation includes a variety of loose and erosional forms, mainly made from anhydrite and red marl with lime intermediate layers. Anhydrite or gypsum has been employed to construct Jahangir monument, which easily erodes as a result of precipitation and acts very flexibly against tectonic pressure and, thereby, it gets deformed. It is noteworthy that marl is made of erodible sediments of soft silt and clay, which are used for flooring. The whole slopes of the zone inside the valley and the subarea No.5 are about 6% and 13%, respectively. These slight slopes lead to a calm flow with a low power of sediment carriage towards the river inside the valley. Therefore, the sedimentation power of the river and its canals in the adjacency of the ancient structure will be very high. According to the historical texts, two major earthquakes occurred in 3 & 4 centuries AH and the available data are consistent with earthquake studies in the database of seismology and building. Indeed, the majority of the historical recorded earthquakes in the area have been above 6 on the Richter scale in magnitude, which are classified into the category of dangerous earthquakes. This type of earthquake, due to its high kinesthetic power, has ruined the ancient structure and, thereby, the remains of each earthquake are visible in the form of cracks, collapsed walls, and tilted vertical and horizontal lines in the structure. Field observations of sedimentary layers, i.e. fillers of the interior space of the building, which have been obtained during the excavation include the constituent elements of sediments; and the proper layering, smooth slope, and consistency of the order of the sedimentary outcrop inside the building with other sedimentary outcrops around the zone indicate that this ancient structure has been influenced by the natural factors dominant over the region in the past decades. The sedimentary consistency suggests that the building has been buried under the influence of Kangir River, its floods, and sedimentation. Based on studies, water erosion and cross-sectional sedimentation are very active in the valley and this feature has become problematic for the ancient structure. In addition, rainfall and the passage of many surface run-offs during the year cause the simultaneous erosion of the building materials and walls (due to its gypsum type) and, on the other hand, it leads to its further deposition and burial. Its proximity to agricultural lands and residential areas as well as its situation near the dam are among the other human factors negatively affecting the survival and durability of this structure. Therefore, it is necessary to provide solutions to protect this structure against the natural and human threats imposed on it. By means of geological studies on historical eras, one can analyze the variety of variables involved in the construction of a building and its deployment in order to opt for a suitable Restoration of monuments method for its conservation.

The 200 km long Gailatu-Siah Cheshmeh-Khoy (GSK) fault, with the same trend as the North Tabriz, Chaldiran, Nakhichevan and Pambak-Sevan-Syunik faults, is regarded as a part of the strike-slip fault system in the middle of Arabian and Eurasian collision zone, which extends from 42˚ E to 48˚ E with the Tutak and North-Tabriz faults in the west and east, respectively. This system includes a series of right-lateral strike-slip faults between the southern front of the Lesser Caucasus in the northeast and Bitlis-Zagros suture zone in the southwest. Tchalenko (1977), Apart and Iz (1977) and Baraka and Kadinsky-Cade (1988) was studied different segments of GSK fault and Berberian (1997) and Karakhanian et al. (1998, 2002 & 2004) describe them as a unified active strike-slip fault. Different sections of GSK fault was named by previous authors as the Northwestern Fault System (Tchalenko, 1977) and Balikgölü fault (Baraka and Kadinsky-Cade, 1988), as well as, considering this fault as the western continuation of the North-Tabriz and Chaldiran faults by some authors has been called, North Tabriz-Gailatu fault system (Krakhanian et al., 1998) Balikghel-North-Tabriz fault (Karakhanian et al., 2002), Guilato–Siahcheshmeh–Khoy– Tabriz (Solaymani Azad et al., 2015) and Chaldiran-Khoy fault (Berberian, 1977). During historical times, some destructive earthquakes especially on the northwestern parts of GSK fault have been occurred. The disastrous M=7.4 earthquake of 1840 A. D., reported as a strongest historical earthquake along GSK fault, destroyed the region along the NW part of this fault and more than 1000 people were killed in the towns of Maku, Dogubayazit, Avajigh (Kelissa-kandi) and many villages around NW part GSK fault (Ambraseys and Melville, 1982). About 72 km surface rupture along this and eruption of Ararat volcano is presumably was related to this event (Ambraseys and Melville, 1982; Karakhanian et al., 2002). After 3 years, an earthquake in 1843 A. D. devastate khoy city and killed between 500 and 1000 people (Berberian. 1977). Maku, Avajikh, Siahcheshmeh and its surrounding area, in 1968 A.D. damaged by Bedavli earthquake, considered to be related to activity of GSK fault (Berberian. 1977). Earthquakes of 363 A.D., 1319 A.D. (Qara Kelisa earthquake), 1808 A.D., 1834 A.D (Pambukh earthquake), 1900 A.D. and 1970 A.D. (khoy and Badalan earthquakes) are the other moderate historical and instrumental earthquakes of GSK fault (Ambraseys and Melville, 1982; Berberian. 1977).  Outlines of this fault is very obvious and display a series of well-developed and preserved morphologic evidence indicating recent activity of the fault, same as, fault scarps and horizontal deflection in the Quaternary features, pull-apart basins, hot water springs and uplifted terrace deposits. The available literature, fault plane solutions, offsets of various geomorphological, man-made features and basaltic lavas indicate the right-lateral strike-slip nature of the GSK fault. Debate on the eastern and the northwestern terminations of the Chaldiran and North-Tabriz faults, respectively, have been raised in the few recent decades.  In this paper, we investigated linkage of the North-Tabriz and Chaldiran faults, to the southeast and northwest of GSK fault, respectively.  This paper also provides critical data for the Quaternary slip rate and kinematic behavior of the GSK fault. One of the remarkable structural features is the Siah Cheshmeh pull-apart basin at a right step-over of the GSK fault. Two remarkable offsets along the strike of GSK fault define its horizontal slip rate. To determine long-term slip rates, Copley and Jackson (2006) studied two morphological features that have been displaced along the GSK fault up to 13-km, SPAB and Agchay river. By using these displacements, they estimated an average horizontal slip rate of 2-4 mmyr-1 since late Miocene along GSK fault. Along the SK,  Quaternary basaltic lavas, known as Maku basalts, form a few ridges that are elongated parallel to the strike of the fault and displaced by ~ 725±50. Using the about 400 kyr published age of these basalts (Pb206/U238 and Ar40/Ar39 dating methods, Allen et al., 2011; Lechmann et al., 2018), a mean slip rate is 1/65 ± 0.1 mmyr-1. On the SK segment, we excavated a trench to determine the fault geometry and its rake, and assessment of offsets which conditioned by the fault activity. In the trench, faults are shallow dipping with thrusting components that resemble foreberg structures in pressure ridges along strike-slip faults. Radiocarbon dating of the youngest deposits in the stream wall which displaced by 42±4 m, yield 6764±283 calBC, indicate the horizontal slip rate of 4.6±0.3 mmyr-1. Also, ourOur field observations have not identified any step along the SK segment, where more than four releasing and restraining bends have been reported by some authors along the GS segment. The existence of multiple bends along the GS segment relative to SK fault indicates lower geological offset of GS fault relative to SK fault, in accordance with theoretical consideration of Wesnousky (1988) for strike-slip faults. Based on this theory, the number of steps per unit length along the trace of strike-slip fault zones is a decreasing function of cumulative geological offset. In addition, published geodetic results show that the largest displacements occur along the North-Tabriz and Chaldiran faults, in the northwestern Iran and Eastern Turkey.  Our results indicate that, SK segment of the GSK  fault, due to its greater activity relative to its GS segment, can be considered as the western and eastern continuation of north Tabriz and Chaldiran faults, with a high slip rate.

The most of previous study about tectonic activities concern to the seismic evidences. But, we observe destroyed region due to tectonic activity without seismic evidences. Therefor for the accurate evaluation of tectonic activity, recently the morphotectonic assessments with other studies are used. Hence, in this research, we try to indicate the areas with the high relative tectonic activity based on assessment of the morphotectonic indices in the southern edge of central Alborz and analysis of these indices according to the tectonic and climate conditions. These areas can be the regions with high potential hazard in future. In this study, first we prepare the Digital elevation model based on the several topography maps in GIS. Then, the morphometric indices are calculated and evaluated. Since the priority value of these indices is different in the evaluation of relative tectonic activity in the area, we use analytical hierarchy method (AHP). Based on these data, the study area divided to several regions with different tectonic activity classes. The most of the subbasins according to the North Tehran fault (specially the central segment of the fault) in the southern edge of the central Alborz indicate the high and very high the tectonic activity. The evidences demonstrate tectonic activity classes 1 and 2 relate to the area between Amamzadeh Davood fault and North Tehran fault. The eastern Taleghan fault zone and the western segment of the Mosha fault in the Northwest of the area correspond with high class of relative tectonic activity. Also, in this research, the results, the final map and morphotectonic assessment indicate the subbasins according to the Ipack fault, Eshtehard fault and Limited regions of the North Ghazvin fault are compatible with high and relatively high classes.