شناسایی و تفکیک زون‌های آلتراسیون در محدوده اندیس مس- طلا سربیشه با استفاده از داده‌های ماهواره‌های ASTER

Abstract

Sarbisheh mineral occurrence is located in the vicinity of the Tourshab village about 50 km south of Birjand, the center of Southern Khorassan province, east Iran. The predominant geologic characteristics of the region are highly-tectonic deformation, and intrusive, granodiroritic-dioritic, to volcanic, dacitic-andsitic rocks associated with broad alteration. To the northern part of the studied area, extensive variety of alteration, kaolanitic, sillicified to choloritic, can be observed clearly in the filed and remotely sensed data. Concerning to previous geologic works, these alteration zones have been formed apparently NW-trending extensional trends. This is more obvious feature to the southeast part of the area where the main tectonic features with NW-SE trend delimited the southern border of Kaolinitic alteration in adjacent of the Torshab spring. Based on previous geologic surveying and preliminary mineral prospecting, the area apparently has a convincing mineral potential, especially for copper, gold etc., to encourage some governmental organization or any private company to launch more detailed exploration study. The main goal of the present study was to introduce an integrated method for mineral exploration for the copper-gold prospects using the remote sensing and field observations and to produce different alteration maps. To distinguish between different types of alteration developed within the studied area, ASTER satellite data were collected and analyzed using various methods. In this manner, argillaceous alteration haloes and iron-oxide zones representing possible high-mineral potential extents were extracted successfully by applying the Korsta method. Meantime, other remote sensing techniques, such as color composite maps, principle component analysis, supervised classification, least-squares fit, band rationing and MF methods. By applying the above methods, this study produced different accurate alteration maps of the area.