Iranian Journal of Geology
Year:2012 | Volume:6 | Issue:23|Papers Count:6

Taknar complex which is situated at the Taknar structural zone is in northern part of Central Iranian microcontinent. The position of this assemblage is at the 20Km of northwestern of Bardaskan County. Taknar complex with Late Jurassic–Early Cretaceous is the result of extensive magmatism in northern part of Central Iranian microcontinent which is caused by Middle Cimmerian to Late Cimmerian orogenic events. This complex are an assemblage of leucogranite, granite, granodiorite, tonalite and granophyre. The mail texture of these rocks is granular and also we can see porphyroid, pertitic and granophyric textures. The major constitutive minerals of these granitic rocks are orthoclas and microcline with pertitic texture and amorphic quartz. The granodioritic and tonalitic rocks of this assemblage have dark color due to frequent existence of biotite. The granophyre rocks of this assemblage are small apophysis in the old rocks.The magmatic series of rocks in the rocks of this complex are calcalkaline. The chemical characteristics and tectonic environment of the studied granitoidics of the complex are completely similar to each other. From the alomine saturation point of view, the samples are in the range of meta-alomine to per-alomine. In addition to petrographic characteristics, the I-type granites are comparable with the mentioned granitoidics in their geochemical features. These are Medium-K rocks and also enriched in the LILE such as Rb, Cs and Th while depleted in the Nb and Ti. Therefore, it shows that these rocks resulted from the mixing by the lower crust. The comparison of the major and trace elements within these rocks indicates their orogenic tectonic environment. The rocks of this complex are formed at the continental margin and (VAG) environment which it is related to the subduction of the Neotethys oceanic crust under Central Iranian Microcontinent.

The Lali anticline is located about 60-Km northeast of Shushtar in SW Iran and in the Dezful embayment zone. In this research, subsurface data have been used for analysis of folding and fracturing mechanisms in the studied area. Due to presence of a thrust fault in the southern limb (forelimb) of Lali anticline, it is suggested that this anticline is a fault propagation fold. Geometrical analysis methods, including inscribed circles analysis, derivative from subsurface structural maps, calculation axial curvature amount of reservoir structure and relative frequency of fractures method (RFF), are shown that the SW limb (forelimb) of the anticline has higher potential fracture density.

Water quality management is a global important issue. In this study, the application of Fuzzy Set Theory is used to evaluate groundwater quality for drinking purposes. Fuzzy Synthetic Evaluation model gives the certainty levels for the acceptability of the drinking water based on the prescribed limit of various regulatory bodies’ quality class and perception of the experts. In this research, 10 groundwater parameters from 176 well samples measured from 2009 to 2010 in Tehran province, Iran. Using Fuzzy Water Quality Model, the groundwater quality classified in three, desirable, acceptable, and unacceptable categories.Results showed only 132 from 176 samples came in desirable class certainty level of 57.4 to 76.3 percent. About 15 samples classified in the acceptable category whose certainty level ranged from 33 to 60.2 percent and the remaining 13 samples classified in not acceptable category with the maximum certainty level of 24 percent.

Several functions have been proposed in order to estimate the rate of erosion of catchment areas. Since the rate of sediment production and transport are governed by many catchment characteristics such as topography, soil erodibility, land use and etc., direct estimation of these parameters is very difficult, expensive and time consuming. Therefore, the best way to calculate these parameters is using parametric models and optimization techniques.These models use optimization methods to estimate production and transport parameters using observed values of river discharge and sediment load in a given period of time. The results of erosion parameter estimation could be used to predict the volume of the sediment load to design the hydraulic structures such as dam reservoirs.In this research, Samani model is performed on the catchment of Kor and Sivand Rivers, and the production and transport parameters of these catchments are estimated using Genetic Algorithm technique. The model was evaluated for 1 to 3-reservoir cases. The model is optimized in two-reservoir for Kor River and 3-reservoir model for Sivand River.

Haftcheshmeh porphyry copper deposit is located about 45 Km northwest of Ahar and about 28 Km north of Varzaghan, East-Azerbaijan province. The main aim of this research is to consider the magma’s specifications and its role in genesis of the deposit. These intrusives are composed of a continuous compositional range including: quartz gabbro diorite/ quartzdiorite, quartzmonzonite, granodiorite. In these rocks, fractional crystallization and magmatic differentiation is obvious. The chemical composition and mineral assemblages of the studied rocks correspond to high-potassium calc-alkaline rocks which belong to the magnetite series of the I-type in subduction zone. But the results of this study also emphasis on the importance of evaluating samples for the presence of crustal contamination. Field observations and petrographic studies demonstrate that the emplacement of Haftcheshmeh stock took place in a single phase, associated with hydrothermal ore fluid formation. The hydrothermal fluids lost most of their volatile components to the vapor phase and deposit most of their metals as Cu-Mo mineral. Then, boiling is the most generally effective ore depositional mechanism in Haftcheshmeh porphyry deposit. In this deposit, supergene enrichment zone is not developed.

Potential field methods have been used as a practical tool to do reconnaissance of the operation area and primary investigation. In these methods various filters such as different orders of horizontal and vertical derivatives and combination of them have been applied to locate the anomaly source and boundary of the geological structures. Derivatives of the potential field as the high-pass filters intensify high frequencies of the shallow anomaly sources and weaken low frequencies of the deep anomaly sources. These derivatives are sensitive to the noise level of data significantly and intensify the noises which are high frequency variations in data and cause decreasing the parameters of the signal such as signal-to-noise ratio and resolution. Although the first and second derivatives have been used routinely in interpreting potential field data, the non-integer or fractional orders can be applied to determine the most efficient order of derivatives. In this study, fractional order derivatives and application of them on the potential field data have been discussed. Results of the different fractional orders of horizontal and vertical derivatives and enhanced analytic signal of synthetic data have been shown to determine the efficiency of this method. Random noises have been added to some models to simulate the real cases. In addition, different fractional orders of enhanced analytic signal have been applied on real magnetic data of the Gazestan region. Results of this study show that optimizing quality and spatial resolution in qualitative interpretation of potential field data can be achieved by applying non-integer order derivatives to find the highest order of horizontal and vertical derivatives and enhanced analytic signal.