JOURNAL OF GEOTECHNICAL GEOLOGY (APPLIED GEOLOGY)
Year:2012 | Volume:7 | Issue:4|Papers Count:8

This research studied the coastal regions of southern Sistan and Baluchestan Province, which play a significant role in the international trade, Coastal management and marine industries. Determining suitable lands is very important for the development and construction of marine structures such as fueling, fishing, commercial jetties and coastal ports without environmental pollution. The research uses the existing references and documents in libraries, field and survey research method, and collecting coastal sediment samples from both surface and depth. By collecting thin sections, the sediments of the area are studied and their types are determined. Finally, combining these two sources of information, potentially suitable and unsuitable areas for the construction and development of jetties, ports and fuelling jetties are determined. In this study, it was shown that factors such as fluctuations in the sea level, tectonic processes, climatic atmosphere, hydraulic processes, especially tidal currents, human interference, and construction activities in the jetties and these coastal regions are the most destructive and constructive forces at work in the coastal regions. It was also revealed that Chabahar and Pozm coasts are clear indications of retrograde beaches of advanced sea. Oman coastal regions are exposed to two groups of marine and land factors due to the continuing uplift and subduction zone processes. Geological reasons are considered as the main factors. The rock units, affected by alteration processes such as dissolution, degradation and alteration of its components, have eroded severely. This fact makes the beaches prone to shock waves and local loading. In some places such as western Passabandar and eastern Ramin, these factors alone caused the separation and collapse of the rocks and, as a result, the withdrawal of the coast. While in some other areas, like sea walls separating the Pozm and Chabahar and Goater coasts, hydrodynamic factors such as waves' effect climatic conditions, monsoon winds, and wind erosion are the complementary factors in the erosion and the withdrawal of the rocky beaches.

The aim of this research is the recognition of karst geomorphological phenomena, lithology and physical properties of carbonate rocks in order to assess karst development in Nahavand area. Based on field observations, the carbonate units in the region are much expanded. The tectonic structures (discontinuities and faults) are abundant and karst geomorphologic phenomena such as dolines, ponors, karrens, caves and karstic springs are well visible in the area. According to the study of thin sections and Folk classification, the studied limestone rock types have been dolomitized bioclast packstones and calcareous mudstones. According to the results of XRF analysis, the percentage of CaO for all three rock types are higher than 50% and the maximum and minimum of MgO percentage in samples are 2.47% and 1.39% respectively. In addition, the results of XRD analysis indicate that the mineralogical composition contains calcite, quartz and dolomite based on their frequency. However, determination of physical properties showed that studied samples have low porosity and high density but lithological appropriate composition, frequency of fracture system, secondary porosity and karst geomorpholgical phenomena, indicate karst development and extension in the study area.

Dalli is one of Cu-Au porphyry mineralized areas in the Urumieh–Dokhtar volcanic belt. Exploration programs were checked based on the results of soil systematic sampling, surface and borehole drilling exploration, and interpretation of geochemical data. The Au and Cu anomalies in northern Dalli were separated by using fractal geometry for 165 soil samples. Anomaly areas showed good coincidence with quartz diorite porphyry, QDP, rocks. According to the lithogeochemical data from TR04 and TR05 trenches (in hypogene area), and the ratios showed good correlation with Au and Cu variations in QDP rocks. The two ratios were introduced as geochemical exploration indices. The trenches and borehole data, with the same azimuth, identified the anomaly areas in QDP rocks and especially contact of QDP and andesitic rocks.To evaluate the location of the mineralized areas under the surface, the geophysical surveys and drilling programs were conducted on the geochemical anomaly areas. The second drilling program was focused on the contact of QDP and andesitic rocks based on the primary drilling program.

In the research, first, all the effective factors in landslide occurrence were derivate using existence resource and then, the nine factors including slope, aspect, elevation, precipitation, and distance from road, distance from fault, distance from drainage, land use and lithology were distinguished as the effective factors in landslides occurrence in the studied area. In continuance, the locations of landslides were prepared using geography information system and aided areal photographs, satellite images and LSM performed. Then, the susceptibility mapping was performed with four methods including information value (WINF), valuing area accumulation (Wa), Analytical Hierarchy Process (AHP) and Gopta- Joshi proposed method (LNRF). Finally, in order to evaluate the verification of the susceptibility mapping, the obtained weights from the Chardavel watershed using the above five methods were used for the adjacent basin (Zangvan watershed), which has similar characteristics to the Ilam dam basin. Results showed that the information value gives better results for differentiation of hazard classes. Therefore, this method is proposed as the best landslide susceptibility mapping for the area.

In this study some heavy elements of groundwater and soil of the Assaluyeh alluvial plain has been evaluated and elements correlation, distribution and trend changes have been compared. Correlation coefficients between heavy elements and other actors; particularly pH, Na, Cl and HCO3 of water samples determine, the geochemical nature and similar behavior of these elements in water. The results indicated high concentration of some heavy metals in soil and water samples. Accordingly, concentration of F and B in groundwater and Pb, Mn, Sr and Ni in some soil samples was more than WHO standards.

Urmia Lake is one of the biggest and salt over-saturated lakes in the world. It is located in the northwestern part of Iran. Today, it has been endangered by drying up processes. This environmental hazard is one of the most significant geological problems of Iran. Verification of evolutionary history of the Holocene and understanding the reasons for sudden downfall of Urmia Lake water level is the main subject of the current study. In this research, remote sensing examinations for a period of 35 years, 55-year climatic data processing and their relationship with the lake water fluctuations were implemented, and undisturbed sedimentary cores of western lake sediments were prepared by Auger coring method. 16 cores having a maximum depth of 9 meters, and totally 98m of the lake sub-floor sediments were verified. Sedimentary facies were separated by color, grain size, mineralogy specifications, sedimentary fabrics and evaporative minerals. With regard to vertical sedimentary facies (from surface to sub-surface areas) changes, geography, climatic conditions and Lake water level fluctuation were re-constructed. Results indicated 17 separable types of sedimentary facies in cores. Facies are from lacustrine, playa, swamp, fluvial and terrestrial environments. Coring and verification of Lake Sub-environment sedimentary facies indicate that sequential drying up tracks are visible in the coastal areas of Urmia Lake. However, the main part of the lake has had lacustrine environment (6.5m of the lake floor sediments) for 13000 years. Sedimentation was continuous during the mentioned period and seismic data confirm this issue. Climate change and particularly evaporation increment are significant agents in the downfall of lake water. But these are not the main causes for drought in the Urmia Lake region. Iran has experienced a long-term drought since 13000 years ago up to now. Hence, shallow lakes, such as Maharloo, Mirabad and Zarivar were frequently dried. It is important to note that Urmia Lake has never experienced dryness except in coastal areas. The main stage of Urmia Lake region drought commenced about 13000 years ago. This event indicated coincidence with the last Ice Age. Regarding the Ice Age, downfall of moisture and lakes' water levels of North Africa and southern Asia was pointed out. Therefore, today, the important agent in the downfall of the Urmia Lake water level is an anthropogenic factor.

Sabzevar Ophiolite Zone (SOZ) is located in northern Central Iran (north of Great Kavir fault and south of Miamey fault) and separates Kopp e Dagh sedimentary basin (in the north) from the Central Iran plateau (in the South). The evolution and replacement time of this ophiolite complex has been in the Upper Cretaceous) Santonian – Campanian) and the Middle Campanian to Upper Maastrichtian respectively. This ophiolite belt contains a high amount of ultramafic rocks, small masses of gabbros and a thick sequence of submarine basaltic lavas with Upper Cretaceous pelagic limestone and radiolarite, which are angular unconformable and have a base of conglomerates of volcanic and sedimentary rocks. This study examines the brittle structures of SOZ and carries out a geometrical analysis. The purpose of this study is to obtain a suitable structural model consistent with the area structures. In this paper, the geometrical condition is compared with all the area structures and a logical relationship between fractures has been identified. Also the relationship between the regional macro-structures and area fractures has been identified. For this purpose during the field visits and study of the satellite imagery, structures and exposure which make the base of a structural map of the area have been provided.. Then with the surveyed data and provided rose and contour diagrams the main direction of fractures and the pattern of orientation were obtained. This direction is N59W, the same trend as the Miamey fault. The structures in the region are affected by this fault. If this direction is considered the main right-lateral shear trend, other trends are consistent with pattern of fractures orientations Related to fault cutting. Generally the fractures with N14E, N68E, N86E, N77W, N59W and N41W trend, respectively are consistent with type X, R', T, R, D and P fractures.