| چکیده انگلیسی مقاله |
Study area in Saghand fifth anomaly has located in central Iran zone and Bafgh-Posht-e-Badam metalogeny belt. Uranium, thorium and Rare Earth Element mineralization are hydrothermal and metasomatism type related to area intrusion body (granite and gabbro available in north of the study area). Uranium concentration of hydrothermal type followed to deep fractures system and remain around of magnetite body , the cause suitable geochemical, and alkalan metasomatism phenomena with uranium , thorium with rare earth element are important metalogeny cycle in central Iran and study area. Because purpose of article is assessment of radioactive element in area Saghand fifth anomaly, because these elements were lithophile and their concentration is granite magmatism and basic. Radioactive element (U, Th), in metasomatit and igneous rocks, that we separate alterations of uranium and thorium with remote sensing method. Alterations related to U and Th hydrothermal mineralization are hematitization, argillic, carbonate, chloritization and silicates. Total features have processed in this article contain argillic alteration (kaolinite, montmorillonite, illite), prophylitic alteration (epidote, chlorite), siliceous alteration, Fe oxides (hematite, magnetite, goethite) carbonate (calcite, dolomite) and albite, with major and minor lineaments. Using methods for alteration extraction are LS-Fit (Linear Band Prediction), Matched filtering (MF), Spectral Angle Mapper (SAM) and Spectral Feature Fitting (SFF), Ratio band and visual interpretation. The result comparison of different algorithms illustrate that best algorithm for argillic alteration extraction are Matched Filtering (MF) and Spectral Feature Fitting (SFF), Carbonate alterations are Matched Filtering (MF) ,7+9/8 band ratio with visual interpretation, argillic and carbonate alterations used visual interpretation with RGB:468 that carbonate seen yellow and, argillic is pink-red color. Prophylitic alterations are Matched Filtering (MF) and 6+9/7+8 band ratio and best method in identification of siliceous alteration is 12/13 , 13/12 band ratio. Fe oxides alteration used with LS-Fit and 2/1, 3/1 band ratio. Best method for albite is Matched Filtering (MF), LS-Fit (Linear Band Prediction) .lineament extracted with visual interpretation in color composite RGB: 741,742 with ETM and Aster satellite image. |