فصلنامه زمین شناسی ایران
پیاپی 68 (زمستان 1402)

Sabzsang copper deposit is located in the North of Saveh, Markazi province. In this deposit geophysical surveys and extensive surface exploration activities containing litho-geochemical, stream-sediments and trenches sampling have been carried out all over the study area. Also, five azimuthal boreholes have been drilled in a square area with dimensions of 100*115 m in the east of the deposit. In this research, lineaments in the Sabzsang deposit were first identified using the magnetometry method. To achieve the goal, the variety of required filters especially edge detection containing horizontal derivative, analytic-signal and tilt derivative was applied on the magnetic data. Afterward, relationship between the lineaments and copper mineralization was investigated using the performed direct explorations. In this regard, the qualitative correlation between the lineaments with surface copper mineralization for the entire area of the Sabzsang was determined, as the qualitative and quantitative correlation between the lineaments with copper mineralization of various surface and deep works in the area of drilling boreholes. The results of the research show that the mineral depositing in the Sabzsang area is mostly shallow, indicating a very high qualitative accordance between the lineaments and occurrence of mineral deposit in the entire surface of the area. To determine the quantitative correlation, first, 2D grid-based map of lineaments was produced. Then, the copper assay data and number of lineaments were interpolated within a same size range after the same gridding. At the end, a very weak correlation with a correlation coefficient of -0.02 was obtained between the copper assay data and lineaments in the eastern part of the deposit. This means that the mineralization has been performed in the dominant fractures but by effecting several factors, the grade of mineral deposit in mentioned locations is not necessarily high. The results of this research serve as a key and guide for decision-making to proceed the detailed exploration stage of the deposit.

One of the most important potential sources of salinity in southern Iran is the dissolution of salt domes, which in most cases leads to the deterioration of the quality of surface waters, karstic aquifers, and adjacent alluvial aquifers. Although karstic and alluvial waters generally have good quality, in many cases in the south of the country, the quality of these waters has decreased due to contact with salt domes. This issue is particularly important in areas such as the lands located on the coasts of the Persian Gulf, where the groundwater level is high. Given that some areas of Hormozgan province, such as Hormuz Island, are composed of salt-susceptible soils with a high percentage of sulfate and gypsum, the occurrence of problems such as subsidence, deviation, and high susceptibility to dissolution is likely. Therefore, this article focuses on examining and evaluating the determination of the susceptibility to dissolution and the resistance characteristics of soils in the areas adjacent to the salt domes on Hormuz Island. The determination of resistance characteristics and susceptibility to dissolution has been carried out based on the results of physical, chemical, technical, and mechanical tests using boreholes and sampling. Some of these characteristics include soil classification, soil moisture content, salt percentage, chloride and phosphate content, maximum density percentage, friction angle, soil cohesion, elasticity modulus, and soil compaction index. The results showed that the presence of salt has led to a decrease in resistance parameters (internal friction angle and cohesion) of the soil. This reduction in cohesion in salt-containing samples compared to natural soil samples without salt has been more pronounced. In addition, the presence of salt leads to an increase in optimal moisture content and a noticeable decrease in maximum dry density of the highly susceptible dissolution soils compared to natural soil samples. Finally, based on the obtained data and the precise identification of susceptible dissolution soils and consideration for future construction in these areas, proposed solutions for preventing and controlling damage to structures on this type of soil have been presented.

The Anar fault in the east of Yazd city, with a north-northwest-south-southeast strike, is a basement fault that separates the Yazd block from the Posht Badam block, and its current activity is a dextral strike-slip with a reverse component. The paleostress analysis was done on this fault in order to obtain the tectonic history of central Iran in the period from Devonian to Cretaceous. After analyzing 110 fault data in 13 stations of 2 tectonic phases, it was determined that the maximum stress obtained is between the azimuths of 90 to 110 and 190 to 220 and the angle of stress direction changes in the period from Devonian to Cretaceous is 130 degrees. Based on the studies on the barite veins and the dextral displacements that were seen on them, the separation of the stress phases was done, which indicates that the NNE stress direction is older. Further, according to the previous studies of sedimentology and tectonics in central Iran, it was concluded that the cause of this change in tension was the movement towards the northeast along with the 130 degree counter-clockwise rotation of central Iran.

Study area is located in Eastern Azerbaijan province, 27 km far from east Bostanabad, and the north of Qarehchaman geological map. According to field tracking and surveys, host rock of mineralization is a Subvolcanic rocks of Oligocene period. Based on microscopic studies, the most important of supergene part, containing primary oxide minerals (Magnetite), secondary oxide minerals (Malachite, Hematite and Goethite) and also sulphide minerals such as Chalcocite, Covellite, Pyrite and insignificance Chalcopyrite. Among the most important alterations, argillic, silicification, carbonization and propylithic can be noted. Geochemical studies shows that host rock of mineralization with Monzosyenitic composition, placed in high chalc-alkaline to shoshonitic and metaluminous range. Formation environment of host rock of mineralization is a volcanic arc of subduction zone that confirmed by normalized rare earth elements diagrams.

Gysian ophiolite is a remnant of the Neotethys, located in the north-west Iran at the intersection of the ophiolite belts of south-eastern Turkey, north-eastern Iraq and north-western Iran. The geochemical comparison of the soils with the average of global rocks and the study area led to determination of the composition group of the region soils. The geochemical evidence of the first group of soil samples with low silica percentage by Harker and triangular diagrams is close to the position of ultramafic rocks of the region (serpentenites) and primary mantle and expresses their compositional similarity. The second group of soils ranges in the area between the earth's crust and basalt, and they show more distribution near basalt. The normalized pattern of REE rare earth elements in this group of soils is similar to the mafic rocks pattern in the region, also in the minor elements chart, they classified in the mafic group. Soils with high percentage of silica in the diagram of major and minor element oxides are located near the positiion of meta-plates rocks in the region, in the range between the earth's crust and global shale. So, this suggests the intermediate composition of their origin. Most likely, the tectonic setting of the three soil groups is based on the oxides of the main elements of the active continental margin.