Application of ASTER SWIR data on detection of alteration zone in the Sheikhabad area, eastern Iran
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ORIGINAL PAPER
Application of ASTER SWIR data on detection of alteration zone in the Sheikhabad area, eastern Iran Mohammad Reza Mahdevar & Pourya Ketabi & Nader Saadatkhah & Jafar Rahnamarad & Seyed Saeid Mohammadi
Received: 31 May 2014 / Accepted: 14 August 2014 # Saudi Society for Geosciences 2014
Abstract This research was focused on different techniques of remote sensing to identify the external alteration structures at Sheikhabad region, especially mining exploration of hydrothermal alteration of typical structure using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data. We have applied the ASTER data, including three visible and near infrared (VNIR), six shortwave infrared (SWIR), and five thermal infrared (TIR) bands to determine the alteration minerals of Sheikhabad area. Spectral analysis of the surface reflectance SWIR manifests absorption in 2.20 and 2.33 μm wavelength regions. Absorption at 2.20 μm (band 6), due to Al-OH anionic agent is consistent with the presence of clay minerals (illite, kaolinite) and sericite, whereas absorption at 2.33 μm (band 8) due to Mg-OH anionic agent and carbonates is consistent with the occurrence of chlorite, epidote, and calcite minerals. In this research, by using the satellite image processing of ASTER sensor, different methods such as false color composite (FCC), band ratio (BR), and principal component analysis (PCA) as well as the direct data from the Mokhtaran geological map (1:100,000) were applied. The results obtained from ASTER data are
M. R. Mahdevar National Iranian South Oil Company (NISOC), Ahvaz, Iran P. Ketabi : S. S. Mohammadi Department of Geology, Faculty of Science, University of Birjand, Birjand, Iran N. Saadatkhah Department of Geotechnics and Transportation, Faculty of Civil Engineering, Universiti Teknologi Malaysia, Skudai, Malaysia J. Rahnamarad (*) Department of Geology, Faculty of Science, Zahedan Branch, Islamic Azad University, Zahedan, Iran e-mail: [email protected]
compatible with the conclusions inferred from petrology and X-ray diffraction (XRD) studies of the surface samples. Based on petrographic studies, these rocks have different compositions and include trachyandesite, andesite, rhyodacite, and porphyric diorite. According to petrology and chemical analysis (XRD) and remote sensing results, six alterations zones consisting of kaolinitization, silicification, alunitization, carbonatization, sericitization, and propylitic are distinguished; thus, it is suggested to explore Cu-Au mineralization. Keywords Alteration . Remote sensing . Aster image . Sheikhabad . Southwest of Birjand . East of Iran
Introduction Recently, hydrothermal alteration has been mapped using remotely sensed spectral data. Visible and near infrared/ shortwave infrared (VNIR/SWIR) data collected by multispectral instruments have been used to map minerals and identify altered areas (Rowan and Mars 2003; Mars and Rowan 2006; Di Tommaso and Rubinstein 2007). The widespread range of satellite imagery is used for mineral explorat
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