Mirko Ahmadfaraj - School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
Mirsaleh Mirmohammadi - School of Mining Engineering, College of Engineering, University of Tehran, Tehran, Iran
Peyman Afzal - Department of Mining Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran- Camborne School of Mines, University of Exeter, Penryn, UK.

The aim of this study is determination and separation of alteration zones using Concentration-Area (C-A) fractal model based on remote sensing data which has been extracted from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. The studied area is on the SW part of Saveh, 1:250,000 geological map, which is located in Urumieh-Dokhtar magmatic belt, Central Iran. The pixel values were computed by Principal Component Analysis (PCA) method used to determine phyllic, argillic, and propylitic alteration zones. The C-A fractal model is utilized for separation of different parts of alteration zones due to their intensity. The log-log C-A plots reveal multifractal nature for phyllic, argillic, and propylitic alteration zones. The obtained results based on fractal model show that the main trend of the alteration zones is in NW-SE direction. Compared to the geological map of the study area and copper mineralizations, the alteration zones have been detected properly and correlate with the mineral occurrences, intrusive rock, and faults.

ASTER, Concentration–Area (C-A) fractal model, hydrothermal alteration mapping, Principal Component Analysis (PCA), Saveh