Mapping the alteration footprint and structural control of Taknar IOCG deposit in east of Iran, using ASTER satellite data

Abstract Taknar Fe + Cu ± Zn ± Pb ± Au ± Ag deposit in northeast of Iran is studied by Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) reflectance and emittance data. Structural and mineralogical evidences of IOCG mineralization is mapped by visual image interpretation and spectral processing techniques. The tectonic model is consistent with an extensional zone associated with a releasing bend of right-lateral regional faults, extending about 7 km2 and encompassing all the known orebodies of Taknar. A combination of band ratio logical operator and matched filtering were used for spectral mapping, which lead to a series of mineral content and crystallinity maps including ferric oxide, ferrous, white mica, chlorite, silica and opaque minerals. The channel way in which hydrothermal fluids were migrating is accurately defined by abundance of white mica and ferric iron oxide maps. Rhythmic sediments of Taknar formation which was characterized by chlorite mineral map is a “reducing” environment that hosts the mineralization. This REDOX environment is also marked by a sudden change in white mica composition from acidic phases to neutral/alkaline. Subsequent field check and microscopic study indicated the accuracy of these remotely mapped minerals. Based on this finding, several new prospects for further exploration was proposed. These results indicates that ASTER data is capable of delineating alteration footprints of an IOCG mineral system in deposit scale exploration.

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