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    • List of Articles افشین اشجع اردلان

      • Open Access Article

        1 - Investigation of alterations and lineaments in Rashid-Abad mineral area (N Zanjan, NW Iran), Using integration of Remote Sensing and Aeromagnetic data
        Mahsa Seyyedi Mohammad Lotfi Arash Gourabjeripour Afshin Ashja Ardalan
        In this research, remote sensing and aeromagnetic data sets were integrated to investigate structural features and alteration zones of Rashid-Abad mining area. This area is located approximately 45 km north of Zanjan, in the Alborz (western)-Azerbijan zone, NW Iran. For More
        In this research, remote sensing and aeromagnetic data sets were integrated to investigate structural features and alteration zones of Rashid-Abad mining area. This area is located approximately 45 km north of Zanjan, in the Alborz (western)-Azerbijan zone, NW Iran. For this reason, two main lineaments with the E-W and NW-SE trends were detected using a sun-angle filter of OLI data and, analytic signal (AS) and first-order vertical derivative (FVD) techniques of aeromagnetic data. The other lineaments with other trends in the area are controlled by the same two major lineaments. In order to identify alterations, the methods of band ratio (BR) in ETM+ and OLI, false-color composite (FCC), relative absorption band depth (RBD), and spectral angle mapper (SAM) in ASTER image processing were used in the study area. The results showed the presence of iron oxide, argillic, phyllic, propylitic, and silicic alterations. Also, the area’s aeromagnetic response to different alteration regions was investigated by matching aeromagnetic anomalies with alteration zones. In addition, it was concluded that, iron oxide alterations with negative magnetic anomalies, phyllic alterations with moderate positive magnetic anomalies, and also argillic and silicic alterations with moderate to increasing positive magnetic anomalies were associated. Also, propylitic alterations did not show a significant relationship with magnetic values. Manuscript profile
      • Open Access Article

        2 - Magmatic interactions as recorded in plagioclase phenocrysts of quaternary volcanics in SE Bam (SE Iran)
        Abdollah Yazdi Afshin Ashja Ardalan Mohammad Hashem Emami Rahim Dabiri Mohammad Foudazi
        In the southeast of Iran (SE Bam), there is a collection of volcanic rocks with andesite, basalt and trachyandesite composition. The textures of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomeroporphyritic, sore throat trachytic More
        In the southeast of Iran (SE Bam), there is a collection of volcanic rocks with andesite, basalt and trachyandesite composition. The textures of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomeroporphyritic, sore throat trachytic. Main minerals include olivine, clinopyroxene, plagioclase and secondary minerals including opaque minerals, Iddingsite, secondary biotite, chlorite and calcite. The analysis of magma textures gives us valuable information about magmatic processes. Micro textures in plagioclase of volcanic rocks in the region are divided into two groups: a) texture-linked to crystalline growth including: sieve texture, oscillatory zoning and degraded surfaces and b) Morphological textures such as glomerular crystals. Sieve texture and zoning in crystal represent processes such as magmatic mixing and abrupt reduction of pressure and, in general, unbalanced conditions in magmatic reservoirs. Based on electron microscope studies, plagioclase of igneous rocks of the region is within the boundaries of labradorite and bytownite.In the southeast of bam, there is a collection of volcanic rocks with andesite, basalt and trachy andesite composition. The texture of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomerulophorphuri, sore throat trachytic. Main minerals include Olivine, Clinopyroxene, Plagioclase and secondary minerals including opaque minerals, Iodenzyte, secondary Biotite, Chlorite and Calcite. Sieve texture and zoning in crystal represent processes such as magmatic mixing and abrupt reduction of pressure and, in general, unbalanced conditions in magmatic reservoirs. Manuscript profile
      • Open Access Article

        3 - Identification of Geochemical Distribution of REEs Using Factor Analysis and Concentration-Number (C-N) Fractal Modeling in Granitoids, South of Varcheh 1:100000 Sheet, Central Iran
        Davoud Pirdadeh Beyranvand Mohammad Ali Arian Taher Farhadinejad Afshin Ashja Ardalan
        The purpose of the present research is delineating geochemical anomaly of REEs in granitoids in south of Varcheh 1:100,000 sheet by the use of C-N fractal model and classical statistical methods. We gathered and studied 59 rock samples for REEs by ICP-MS method in the l More
        The purpose of the present research is delineating geochemical anomaly of REEs in granitoids in south of Varcheh 1:100,000 sheet by the use of C-N fractal model and classical statistical methods. We gathered and studied 59 rock samples for REEs by ICP-MS method in the laboratory of Iran Mineral Processing Research Center (IMPRC). The Concentration–Number (C-N) fractal model was used to delineate elemental thresholds. According to the results, the distribution of elemental concentration for Pr and Sm were divided to three classifications and Ce, La, Nd and Y had five geochemical populations in the area. The classical statistics methods were able to separate three geochemical populations. The results obtained by this study showed that the separation of geochemical anomalies for REEs using C-N fractal model and classical statistics methods yielded to the same results. Meanwhile, the high ratio of LREE to HREE in rock samples as well as high P content, assigns monazite, apatite, and sphene as a possible source of REEs in the study area. Manuscript profile