مجله پژوهش های دانش زمین
پیاپی 49 (بهار 1401)

The Heydarabad ophiolitic melange is hosted by the Nehbandan Ophiolite Complex (NOC), which crops out in the Sistan Suture Zone (SSZ) that marks the boundary between the Lut and Afghan continental blocks. The major rocks of this area include mantle peridotites, listwaenite, gabbronorite, cumulate and layered gabbro, pillow basalt and deep-sea pelagic sediments that were formed in the mid-ocean ridge (MOR). Olivine, orthopyroxene, clinopyroxene and spinel are rock forming minerals of Heydarabad ophiolite mantle peridotite.

After field studies, thin and polished sections were prepared for petrological and mineralogical studies. Whole-Rock major and some trace elements were obtained by X-ray fluorescence (XRF) spectrometer for SiO2, TiO2, K2O, Al2O3, FeO, CaO, Na2O, Cr2O3, MnO, MgO and NiO. Trace element and rare earth element (REE) concentrations were determined by using a Thermo Series X-I inductively Coupled Plasma Mass Spectrometer (ICP-MS). Also, 8 thin- polished samples (least fractured and altered) of wall rock were analyzed by electron probe microanalysis (EPMA), using a Cameca SX100 at the Iranian Mines and Mineral Industries Development and Renovation Organization (IMIDRO) with a 1-3 μm spot size, 20 nA beam current and a 15 kV acceleration voltage.

Most of the olivines from mantle peridotites are serpentinized. The detailed electron microprobe study revealed very high Mg# (62.4 to 67 wt.%), Cr# (18.1 to 34.5 wt.%) and very low TiO2 content (averaging 0.05 wt.%) for chromian spinels in mantle peridotites. The Fe+3 is very low (averaging 0.02 wt.%) in the chromian spinel of mantle peridotites which reflects crystallization under the low oxygen fugacity. The composition of olivine shows that forsterite type (Fo90.07-90.90), orthopyroxene is enstatite, clinopyroxene is diopside and spinels are Al-rich Cr-spinel. Tectonic environment discrimination diagrams for the harzburgite and lherzolite shows abyssal environment.

Hyderabad ophiolite melange consists of peridotite rock units (serpentine and listonite), lherzolite, gabbro, gabbronorite, plate dykes, and pillow lava, which are faulted. The mantle peridotite of this area is composed mostly of harzburgite and lherzolite. Based on mineral chemistry studies, harzburgite and lherzolite have olivine which is forsterite, orthopyroxene which is enstatite and clinopyroxene that is diopside. The peridotites of the study area contain Mg-rich olivines, Cr-spinels and Al-orthopyroxenes and are in the range of deep peridotites based on spinel and olivine chemistry. Also, high Mg value in mentioned minerals and high percentage of forsterite in olivines indicate the tectonic origin of these rocks. Orthopyroxenes and clinopyroxenes are Cr-rich, indicating limited partial melting of peridotites. Mineralogy studies show the relationship of these rocks with the oceanic environment. The composition of spinels in the peridotites shows that the type of high Al, with Mg and Cr is 62.4 to 67 wt% and 18.1 to 34.5 wt%, respectively. They are considered as spinels formed in Abyssal peridotites. Geochemical studies show that Hyderabad peridotites are mantle peridotites that are formed by melting 11 to 16% of a prepared mantle of lherzolitic spinel. The composition of chromium spinels in these peridotites is in the Alpine type range and their tectonic environment is more compatible with MOR peridotites.

Metamorphism, magmatism and metasomatism were active in the Sonqor series and have a significant effect on the geological fate of the region (Mohajjel, 1997). Petrofabric analysis of metamorphic rocks is an effective method in recognizing mechanism of orogenic belt evolution and its’ relationship with plate tectonics (Twiss and Moores, 1992). Emplacement of intrusive bodies associated with tectonic event provide suitable conditions for skarnification, mineralization, alteration and metasomatism in the regions. Tectonic deformation caused the mylonitization of intrusive bodies and metamorphic rock fabric, which is related to orogenic evolution and plate tectonics. Since tectonic structures are considered as the main controllers of mineralization in such areas, it is vital to study tectonics, structures and deformation phases and their affiliation with mineralization for understanding the geometry, grade control and location of associated mineralization.

Microstructures in the Khosrow-abad region were studied during two field surveys mainly in the mineralized area. Fifty-three thin and thin polished sections of skarnified meta basaltic andesite rock units, slatic- and crystalline limestone (marble), quartz monzonitic and syenitic intrusive bodies were prepared and studied using Zeiss Axio-Plan2 research optical microscope in mineralogy laboratory of Kharazmi University in Tehran.

Iron ore mineralization in the Khosrow-Abad deposit can be divided into two types according to the geological and structural features and also based on micro-texture fabrics:1) Ductile type mineralization; the host rock of this type of mineralization is skarnified limestone. Ductile mineralization occurred in Khosrow Abad region in a zone with lens-shaped geometry. Ductile shear zones are also affected by sodic (albite) and magnesium (serpentine and talc) metasomatism. Results of the analyzed samples taken from trenches and boreholes in ductile shear zone indicate low grade iron mineralization associated with highly deformed sections with sodic and magnesium alteration. 2) Brittle type mineralization; the host rocks of the mineralization are alternate of volcanic (meta basaltic andesite) and skarnified rocks with strong deformation. The high-grade iron ore in Khosrow-Abad deposit is associated with brittle deformation. This type of mineralization, which is exposed in the inner parts of the mylonitic zones of the region, includes fractures, veins and oxide-sulfide veins-veinlets that are parallel and intersecting the mylonitic foliation. It seems that the normal faults’ related strain field has led to remobilization, migration, and re-concentration of iron ore along these faults. Deformations has provided suitable spaces and conduits for channeling hydrothermal fluids, causing leaching, alteration and mineralization, even sometimes re-concentration of iron ore. Therefore, the parallel and intersecting joints with mylonitic foliation, has caused a voluminous migration of mineralized fluids and ore deposition within these sub-structures. The highest iron ore grade is observed in the intensely fractured brittle deformation, associated with fragmentation and displacement of mylonitic units and bonds.

The occurrence of vein or replacement structures in the Khosrow-Abad skarn iron deposit is due to the flow of mineralization fluids along the joints and fractures created due to tectonic deformation in the host and intrusive rocks. The tectonic forces caused the occurrence of ductile and brittle shear zones in the region. Considering the association of intense alteration and metamorphism with high-grade iron ore in Khosrow-Abad deposit, it can be concluded that metasomatism and hydrothermal alteration and mineralization in the region, is controlled by deformations and their intensity. The brittle deformation along with the fractures, provide a suitable space and conduits for the influx of mineralized fluids and ultimately the ore precipitation as veinlets, veins, lensoids and deformation fabrics, that controls the magnetite mineralization and its’ grade.

Ahmadabad deposit is the northernmost old mine of Kuhbanan-Bahabad belt, located 10 km NE of Bahabad and is located in the stratigraphic sequence of calcareous-dolomitic Shotori formation. The predominant form of mineralization of Pb and Zn deposits in the region is of vein type, fissure, filling and substitution. Previous studies on the Ahmadabad deposit have considered the sedimentary genesis of the mineral to be sedimentary and the dolomitization to be due to the process of burial diagenesis in a lagoon environment. Due to the fact that the dolomites of the region are the main hosts of mineralization and a large amount of minerals are located in these rocks, the present study has focused on these rocks.

Dolomite-Carbonate units form the main volume of rocks in the area. Necessary information for investigating the genesis of dolomites was obtained from thin-polished cross-section, stable isotopic oxygen data and ICP-MS analysis, which was performed inside and outside Iran.

Microscopic studies show that dolomite crystals are formed in two stages and are visible with a gradual transition border and in some cases sharp border. The bright dolomites of the first stage darken in the next stage. Delayed dolomites are rhomboids with a sharp border and their outer part is covered by iron hydroxides. It is possible that the dolomites are oxidized due to stunted growth of Calcite cement within cavities bounded by dolomite, the presence of some calcite adjacent to dolomites, thick or thin zoning of the sharp boundary between calcite and dolomite, corrosion and dissolving at the junction, the presence of small amounts of Sulfides, oxides. Also, Cu-carbonates with lateral dolomite residues may indicate delayed formation of the oxidized margin of the dolomite. These features are compatible with the characteristics of hydrothermal dolomites in other parts of the world, such as hydrothermal dolomites southwest of the Cantabrian region of Spain. Isotopic data indicate the range of changes of δ18O-SMOW oxygen isotopic composition in the dolomitic rock of Ahmadabad deposit between 23.1‰ to 28.2‰. This value is close to the values reported in other hydrothermal dolomites of the world. The average values of δ18O-PDB in Shotori dolomites of Kuhbanan range are equal to -6.47‰. This value is also in the δ18O-PDB range of other hydrothermal dolomites. Comparison of Fe/Mg ratio in host rock and mineral also shows a 35-fold decrease in this ratio in the host rock. Studies have also shown the relative high level of deposit elements in the host unit. The available data indicate that Mg is used in the mineralization of hydrothermal fluids in the process of dolomitization of carbonate units. Hydrothermal fluids during mineralization have increased compared to poor Mg and its’ Fe content. Comparison of distribution patterns between minerals and rocks in the region shows an undeniable similarity between these minerals and carbonate rocks. The relationship  (  also reveals the increase and enrichment of rare earth elements in light to heavy types. The average ratio in carbonate units is 14.24. This ratio for minerals averages 14.63 and is very close to the average of total carbonates.

The findings of this study showed that the dolomites of the Shotori Formation in the study area were formed under the influence of hydrothermal solutions of metal-rich basins, which were also responsible for mineralization. Evidence from microscopic studies and stable isotopic data of δ18O-SMOW is consistent with the characteristics of hydrothermal dolomites in other parts of the world. The similarity of the normalized patterns of REEs in the host rock and mineral as well as the consistency of the variation in the ratio of Fe and Mg elements between the mineral and the host rock also confirm the result obtained. The similarity of the of the REEs of the host rock and mineral and the concordance of the ratio of Fe and Mg elements between the mineral and the host rock also confirm the result obtained.

Intrusive masses are exposed in the Bostanabad-Mianeh axis with the northwest-southeast trend. The rocks are known as granite in general geological maps. Detailed studies in this study have also shown the presence of syenites which their petrology was considered in order to investigate the Zagros orogeny development in northwestern of Iran. The magmatic rocks of the region are the result of magmatism of the Uromieh-Dokhtar magmatic belt and include intrusive, volcanic and pyroclastic rocks with sedimentary units. Syenites of the Bostanabad-Mianeh axis are along with large volume of granites. Syenites provides important information about the interaction of the crust-lithosphere mantle, magma evolution processes, tectonics and crustal growth. In this study, syenites are divided from granitic rocks and their geochemical properties have been investigated to determine their tectono-magmatic and Petro-genetic conditions.

During field study, samples from the syenite and granite outcrops were collected for petrography, geochemistry and determining magmatic series and the magma origin. For geochemical studies, 13 samples of intrusive rocks with the lowest degree of alteration were chemically analyzed by ICP-MS and ICP-OES methods in the Act Lab Ontario Canada.

The Bostanabad-Mianeh axis in northwestern of Iran and in the East Azerbaijan province is part of the Cenozoic magmatism of the Lesser Caucasus towards southeastern Iran. Magmatism is related to the subduction of the northern ocean of Neotethys during the collision of the Arabian Plateau with Eurasia and its subsequent events. The presence of arc-type magmatism in the regions of Azerbaijan, the Alborz Mountains, Talesh and the Lesser Caucasus all indicate the subduction of the Neotethys branch with the Eurasian plate. Due to the LILE and LREE enrichment and the HREE depletion, the source of the magmas for the studied syenites are originated from an enriched mantle source in the continental lithosphere in the subduction zone belonging to post orogenic extension events. Consequently, the formation of the intrusions is related to mantle melting which is enriched and fed by fluids and melts and finally contaminated with crustal material during the ascent.

ke the same sedimentary conditions in the Lower Cretaceous, the Upper Cretaceous sediments of Iran do not have the same facies features. Therefore, in this study, we try to study the sedimentary environment and microfacies. Using data and geochemical methods of Upper Cretaceous sediments led to valuable information about the environment and conditions of formation and primary mineralogy of Upper Cretaceous sediments across Dombak-kuh.

In Dombak-kuh section, sampling has been done based on lithological and facies changes in the direction perpendicular to the layers and at distances of less than 0.5 m to more than 2.5 m. These sections were stained with red alizarin solution and potassium ferrocyanide to distinguish calcite mineralogy from dolomite as well as iron content and the amount of iron in it with Dickson method (Dickson, 1965). The classification and naming of rocks is based on Dunham's method (Dunham, 1962). In sample naming, an attempt has been made to include all major allocations in sample naming in order of frequency. The percentage of alluvial abundance was obtained ocularly by comparing with Baccelle and Bosellini (1965) comparison tables. The known facies have been compared with the Flugel (2010) facies belt. In presenting the sedimentary model, the terms used in Burchett and Wright (1992) have been used.

Petrogeraphic studies of this sections revealed 11 microfacies (2 microfacies from tidal flat, 1 microfacies from lagoon, 1 microfacies from shoal and 7 microfacies from open marine). All of them belong to carbonate ramp: 1. Dolomicrites – Dolomicrosparaite, 2.  Intraclast Grainstone, 3. Bioclact Wackestone, 4. Bioclast Pelloidal Grainston, 5. Oligosteginids Packstone, 6. Nezzazatinella, Dictyoconella Wackestone-Packston, 7. Lenticulina/Marginotruncana/ Oligosteginids Wackestone-Packstone, 8. Heterohelix /Globotruncana/Macroglobigerielloides Wackestone, 9. Oligosteginids/ Macroglobigerielloides / Heterohelix Packstone, 10. Heterohelix /Globotruncana/Marginotruncana packstone, 11. Globotruncana/ Heterohelix /Macroglobigerielloides Wackestone-packston
 The characteristics of these deposits indicate that the sedimentary environment was a ramp (hemocline). The absence of calcite turbidite deposits, fall structures and large reef and oncoid and piezoidal dams confirms the carbonate ramp environment. The results of elemental analysis and plotting of these values against each other indicate that the Upper Cretaceous sediment limestones primarily had aragonite mineralogy. The plotting of Mn values against Sr / Ca indicates a semi-closed to open diagenetic environment with a high water/rock ratio.

According to the studies carried out in the Dombak-kuh region of the Upper Cretaceous sediments (Cenomanian-Campanian) they have a thickness of 327.7 m, the lower boundary of which is the Tizkuh Formation and is of a steep type. Its upper boundary is a fault which has been disconnected. Cenomanian sediments, which are 54.26 m thick, start with a progressive conglomerate. Then the thoronine sediments, which are 22.85 m thick, first start with thick-layered limestone and then with chert limestone, and then with Oligosthenic limestones which change the facies and settle on it. Kenyasin sediments with a thickness of 19.85 m were observed with a combination of oligoesterated limestones followed by Santonin sediments with a thickness of 182.80 m and then Campanian sediments with a thickness of 48.5 m form the Upper Cretaceous stratigraphic sequence. In these sediments, 11 micro-facies were identified, which include tidal zone with 2 micro-losses, lagoon with 1 micro-loss, dam with 1 micro-loss and open sea with 7 micro-losses. The characteristics of these deposits indicate that the sedimentary environment was a ramp (hemocline). The absence of calcite turbidite deposits, fall structures, and large reef and oncoid and piezoidal dams confirms the carbonate ramp environment. The results of elemental analysis and mapping these values together, indicate that the Upper Cretaceous sediments in this section has aragonite primary compound which is placed in a semi-closed to semi-open diagenetic region with high proportion of water to rock (W/R).

Salt Lake basin of Iran contain about 30% of the total population and 5.6% of the total area of ​​the country. The average annual reduction of groundwater level across this basin is -0.98 m. Due to this issue, Iran Water Resources Management Company has banned the exploitation of seven plains located around the Salt Lake. Therefore, by applying proper management and implementing exploitation management policies, groundwater level declination should be stopped. The artificial recharge approach can be used as an alternative to prevent further reduction of groundwater level. It is necessary to characterize the geological, geomorphological, soil and hydrological characteristics of the groundwater aquifer to select potential areas for recharge. The best places to implement artificial recharge plans are coarse-grained soils, early sandy alluvial soils, rocky soils, karst areas, sandy bedding and seasonal river cone deforestation. Studies have used a number of data-layers to identify potential areas for artificial recharge. The considered factors in each study were selected and evaluated according to the purpose as well as the hydrogeomorphological characteristics of the study area. In these studies, the runoff depth layer as one of the most important features has been rarely used in selecting susceptible areas for artificial recharge. Sharif-Abad plain is of great importance due to intense agriculture activities. Almost 99.9% of the total surface and groundwater consumption in this area (~1411.86 million cubic meters per year) is consumed by agricultural sector which has triggered significant declination of groundwater level.

In this study, 10 data-layers including geology, geomorphology, soil texture, slope, land use, drainage density, ridge density, runoff depth, groundwater level after monsoon and distance from pumping wells are among the factors that define the suitable sites for recharge. Generation of these data-layers were performed in the ArcGIS 10.3 software environment with a 300 m resolution. The rating of each data-layer is conducted in the range of 1 to 4 according to its influence in suitable sites for recharge (1 for the lowest influence and 4 for the highest). The final map of the best sites for artificial recharge across the aquifer area were obtained by overlapping ten rated layers. Spatial cross-correlation between the values attributed the final map and values of the EC in the groundwater.

The final map obtained from the linear weighted combination of ten data-layers was divided into 4 categories including very suitable, suitable, inappropriate and completely inappropriate areas for artificial recharge. The very suitable areas for artificial recharge were characterized with the coarse-grained alluvial deposits, areas with deep groundwater level, low electrical conductivity, intense pumping well density, transverse passage of a fault line and low surface slope. A significant negative correlation equal to -0.635 is obtained between the EC layer and the final overlapped map.

In this study, suitable sites for groundwater artificial recharge in Sharif-Abad plain were obtained using the most substantial factors including geology, geomorphology, soil texture, land use/land cover, slope, runoff depth, lineament density, drainage density, depth of groundwater after monsoon, and the distance from the pumping wells. The results of this study showed that 11.16% and 30% of aquifer area are completely suitable and suitable lands for artificial recharge, respectively. The correlation of the overlaid final map with the corresponding values of the groundwater electrical conductivity equaled -0.635. Due to the hydrogeomorphological characteristics of the study area, an integrated surface and subsurface recharge (feeding pool and well methods) in the vicinity of fault line is recommended to implement the groundwater recharge project. The results of this research and the data-layers used to identify suitable sites for artificial recharge can also be used for other aquifers around the Salt Lake that have similar hydrogeomorphological-climatic conditions such as Sharif-Abad plain.

Natural hazards have always been a major challenge in achieving development. Humans, as one of the most important inhabitants of the planet, play a decisive role in its evolution.  Population growth, technological advances, rapid and unplanned urbanization, poor performance of city managers and planners, insufficient awareness, unplanned urban development, altered urban environment and physical structure, have made urban dwellers more vulnerable. This rapid and unplanned growth in addition to social, economic and cultural problems poses a serious threat to the environment and natural resources. Increasing human exploitation of nature and natural factors have implications such as increasing pollution, social and economic problems, changing climate, changing physical conditions of cities and overall imbalances in population and environmental capacity. In response to this challenge, the concept of resilience has entered the scientific realm. This concept calls for a quick return to the pre-crisis conditions. Today, in addition to tectonic hazards, the issue of climate change and its associated hazards also threaten human societies. Coastal areas are more vulnerable to climate change due to high environmental sensitivity. These areas face increasing challenges and shocks and climate risks. In response to climate change, greenhouse gas emission reduction is often on the agenda, but today, this reduction process alone will not be enough to cope with the climate changes. The success of climate change mitigation programs depends on actions taken locally. City administrators who have been interacting for climate change policies should adopt better policies. In the face of these risks, it is important to know the residents and municipal authorities.

To collect the required data documents and field methods (questionnaire and interview) was used and data was obtained from two groups of residents of Babolsar and urban authorities (Municipality, Governorate, Road and Urban Planning Department, Engineering organization, Electricity Department, Water Department, Agricultural Jihad, Education Department, Red Crescent, Crisis Management). Weather data (from the Meteorological Organization) has also been used. The collected data were processed by statistical tests in SPSS and Excel software and presented in tables, graphs and maps.

 Finally, according to the research findings, it can be stated that in the face of risks, increased resilience should be considered. Resilience is not only about reinforcing a building but also understanding the concept and understanding its solutions, prior to the structure. This will provide grounds for increasing resilience in all dimensions.  Babolsar was selected as the study site in the study, because the city has been experiencing signs of climate change in recent decades and experienced risks in recent years. The findings of this study confirm the low level of knowledge of residents and authorities of the coastal city of Babolsar about climate change and resilience. Most people do not have sufficient knowledge of the ways to cope with the created conditions or the potential risks posed by climate change and this has reduced the resilience of local communities.

Awareness, information and education can be considered by authorities as a practical solution. But the low level of knowledge of urban officials has added to these problems. The lack of long-term plans and the right understanding and analysis of the risks, the lack of climate change adaptation and surveillance plans are problems of the Babolsar coastal institutions. In the face of climate change, public participation is an important factor in managing cities, especially sensitive areas such as coastal cities. Improving the areas of public participation and opinion poll planning and formulation is a major guarantee for dealing with the unknowns. Increased awareness and recognition, self-assessment of local communities, a sense of belonging and results from the implementation of urban governance policy can be very effective in fragile coastal environments. In Babolsar, there has been no exchange of information and communication between local communities and authorities, and this lack of coordination has made both groups less resilient. All the shortcomings expressed along with the increase in urban population in coastal cities and climate change has increased the vulnerability of these areas. Further study of coastal cities and making recommendations to improve the understanding of local communities and urban authorities about the phenomenon of climate change is inevitable.

The city's spatial justice is synonymous with the fair spatial distribution of facilities and resources between different urban areas and the adequate access of citizens to them from a geographical point of view. Because their lack of fair distribution will lead to social crises and complex spatial problems. District 6 is one of the areas of Tehran that due to the relative dominance of spaces and trans-regional uses, faces severe shortages of urban services and per capita green space, health, sports and cultural facilities at the neighborhood level. Therefore, in this article, the dimensions of spatial justice in District 6 of Tehran metropolis have been studied. District 6 is geographically located in the central part of Tehran, which is limited to district 3 from the north, district 7 from the east, district 10, 11 and 12 from the south, and district 2 from the west. This district with an area of ​​2138.45 hectares includes about 3.3% of the city. The largest area within it ​​ is area 4 with an area of ​​79.470 hectares and the smallest of which is area 3 with an area of ​​7.242 hectares. This district is one of the relatively old areas of Tehran, which is located in the city center. The most important administrative-service uses with urban, trans-regional and even national performance scale are located in this region. Also, one of the oldest and largest north-south axes of Tehran, Valiasr Street, passes through the center of gravity of this area.

According to the nature of the subject and objectives of the research, the research method is descriptive-analytical. The information has been collected in the form of documents and library studies. In this study, first, economic, social and physical indicators were selected. The source of citing the indicators and quantities used are data and information of the statistical blocks of the 2016 general population and housing census of Tehran. After the studies, 12 items of economic, social and physical indicators, which could be accessed in the district 6 of Tehran, were extracted for spatial analysis of the mentioned indicators. Then, based on these indicators, using hot spot analysis and spatial autocorrelation in the Ark GAS software environment, spatial analysis was performed in District 6 of Tehran. Finally, Moran's statistic was used to determine the type of distribution pattern or distribution of inequality in District 6.

Findings show that in general, the neighborhoods of Argentina- Saei and Valiasr Square have the most indicators. Also, Fatemi and Ghezel Qaleh neighborhoods have the lowest number of available indicators. While Fatemi and Ghezel Qaleh neighborhoods are among the most populous neighborhoods in Region 6. Also, according to surveys, only 5% of the district is in desirable conditions in terms of spatial distribution, while 45% of the area is in undesirable conditions.

Based on the results of the present study, the neighborhoods of District 6 of Tehran are not in a desirable situation in terms of the distribution of spatial justice indicators.

Humans alter river systems directly and indirectly. Construction of bridge and culvert is one of the anthropogenic interventions which take place. Road-stream crossing (RSC) is essential to be installed on the river lines for roadway transportation, while incorrect and structurally poor RSCs often negatively influence the geomorphology and ecology of river systems. Culvert and bridges can increase stream flow velocity, shear stress, turbulence of flow, degradation and aggradation, development of deep scours, channel braiding and downstream bank erosion. Jones et al., 2000; Wemple et al., 2001 & Blanton and Marcus, 2009, previously worked on the impact of roads on fluvial geomorphology with changing floodplain’s form and function. The difficult issue in survey study is gathering, up-to-date and easy to use data with high accuracy, therefore short-rang photogrammetry was used in this research.

In this investigation, the effect of bridge on river system was analyzed in Jurband village in Mazandaran province. Documentary references, remote sensing (UAV) and survey are 3 methods used. Longitudinal and cross-section profiles were drawn on digital elevation model. The model was generated from UAV with high resolution (pixel size: 4.6 cm). Longitudinal profile was obtained from survey along 400m from upstream to downstream and 8 cross-section sites were selected for detailed study in upstream (U) and downstream (D) of river channel (on bridge section, 25m, 50m, 100m, 200m).

The channel slope is smooth rend. After bridge cross section, the channel bed has collapsed at a rate of 8m gradually. In investigated reaches, all of cross sections had no change in width index except in 25U section. According to coefficient of variation index, parameters were 18.47% upstream and 2.8% in downstream. Maximum depth was in bridge cross section (1.40m) and in 200D (1.18m). The minimum amount of depth maximum and mean was in 25D (respectively 0.74m and 0.37m). There was a significant difference in W/d ratio in upstream to downstream, about 22m decrease in downstream. Cross-section area varies from 25D (65.7m) to bridge section (79.26m). The significant difference of bank-full area was 42% in all selected reaches. According to information, amount of flow velocity altered from 38.1 m/s in bridge cross-section to 18.4 m/s in 25D cross-section. Also, the maximum and minimum rate of Froude number and power stream were obtained at 25D and bridge cross-section respectively. Sinuosity index (SI) of cross-sections were equal with 1 except in 200U (1.30) , 50D (1.20) and 200D (1.10).

  Based on The principle of flow continuity, it can be stated that the amount of discharge was the same in reaches and variation in channel parameters is due to bridge construction. Because of scour in upstream over the time, altitude differences has changed in river bed and bank side between 3-4 m. After bridge construction, degradation in upstream has stopped due to local bed level foundation but sedimentation and widening of channel has increased about 2-3 meter lower than bank side. Nevertheless, degradation and scouring has increased in downstream and bed collapsing has occurred up to 8m after bridge section.

IntroductionNowadays, entrepreneurship is a key tool for rural growth and development in many countries. Therefore, many countries in the world, especially third world countries, have a special view on rural entrepreneurship. An analysis of the studies reveals the need to pay attention to entrepreneurship in achieving development, including balanced rural development. Inequality of development in rural areas on the edge of the desert has occurred, including Damghan city. It’s natural, socio-economic and physical environment systems, has faced many challenges in these settlements, which in general has led to a lack of balanced development in rural settlements of Damghan city. In line with this issue, rural entrepreneurship as a basic and parallel approach to the goals of rural development can be a great help in this regard.

The purpose of this study was to identify and analyze the relationship between entrepreneurial capacity and balanced rural development. The present study was descriptive-analytical based on the applied purpose and research method. Also, documentary and field methods were used to collect data. First of all, FANP model was used to determine the levels of development of rural areas of Damghan city based on balanced development indicators. In the second stage, a T-sample test was used for testing the entrepreneurial capacities in the studied villages. Then, with the aim of spatial analysis of the sample villages, based on the level of entrepreneurship of the cluster analysis test, the studied villages were divided into several suitable clusters. Hierarchical clustering was used for clustering. In the last step, with the help of analysis of variance, the level of entrepreneurship among the villages was compared with different levels of development. A simple regression test was used to investigate the effect of independent entrepreneurship variable on development rate. Finally, a one-way variance analysis test was used to test the mean difference between the variables in the villages (based on the level of development). In the first step to measure the level of development in the villages of the district, considering the nature of the research and the necessity of recognizing and examining the whole rural area, all the villages of the city were examined. Then, in the second step, a sampling process was performed to measure the entrepreneurial capacities in the studied rural area. To select a sample of the statistical population, the villages were classified according to three criteria: level of development, population and natural location. After classification, sample villages were selected using estimation method. In proportion to the number of villages from each class, the sample villages were randomly selected and finally 32 villages were selected as the sample villages.

The research findings showed that there were fundamental spatial differences between the villages of Damghan city. Meanwhile, some villages had a higher level of development and some had a lower level of development. As a result, this situation had led to the formation of an unbalanced spatial pattern in rural areas. On the other hand, the research findings showed that the villages studied were also different in terms of the overall level of entrepreneurship. From this perspective, the villages were divided into three categories. The first cluster or villages with medium to high entrepreneurship, the second cluster included villages with medium to low entrepreneurship and the third cluster included villages with low entrepreneurship. Therefore, after matching the level of rural development and entrepreneurial capacities, our findings showed that there was a significant relationship between entrepreneurial capacity and the level of development of the studied villages. Therefore 31% of the development variance of the sample villages was explained by the entrepreneurial capacity. Data analysis showed that the entrepreneurial situation had a significant difference in some dimensions based on the comparative comparison of the rate of rural development (underdeveloped, developing, relatively developed and developed).

Finally, the present article, based on the analysis of data, information and findings based on them reached the following results it could be acknowledged that with the increase of entrepreneurial capacities in the villages of Damghan city, the level of development will also increase. In other words, it could be concluded that the development of entrepreneurial capacities in the villages of the region could greatly reduce spatial inequalities and balance rural development. This was in line with the new common definitions of rural development that consider entrepreneurship and development as an approach. These aspects are considered innovative in terms of theories of sustainable and balanced rural development.