Hydrothermal alteration mapping using remote sensing technics in volcanic rocks of Tarom ranges , Iran.
2003
Peyrowan, H. R., Doctorate Student of Geology , Islamic Azad University | Ghayoumian, J., Soil Conservation and Watershed Management Research College | Amini, S., Tarbiat Moallem University | Lotfi, M., Earth Sciences College
Hydrothermal alteration zones have significant role in prospecting of epithermal mineral deposits. In this research, hydrothermal alteration zones in Tarom range in Iran have been investigated using image processing of remotely sensed data. The effectiveness of TM data for detecting alteration zones has been assessed. Three band color composite images produced based on optimum Index Factor (OIF) method and known spectral reflectance properties of rocks and alteration minerals in relation to TM bands. The color composite of TM bands, RGB (1,5,7), RGB (1,4,7) and RGB( b1-b2, b4-b2, b5-b7) achieved the most effective method for separation of hydrothermal alteration ( high , medium and low) zones. The color composite of TM bands, 5,3 and 1 displayed as RGB revealed the best band combination for identification of rock types. In the study area, at this image, the Youzbashchai pluton is clearly highlighted and for the first time is reported. Also, supervised and unsupervised classification of the images confirmed the outcrop of Youzbashchai pluton. The results indicate about 15% of volcanic rocks of Tarom range is altered. This means that hydrothermal alteration affect in widespread region at Tarom range. Keyword: Alteration zone, Tarom plutons, Tarom volcaniclastic rocks , TM images, Tarom range
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