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Abstract


Discrimination of the ophiolite rock units using the ASTER data: An experience from Neyriz Ophiolite, SW Iran

Majid H. Tangestani
Majid H. Tangestani
Dept. of Earth Sciences, Shiraz University, 71454 Shiraz, Iran
E-mail: tangestani@geology.susc.ac.ir

Khalil Sarkarinejad
Dept. of Earth Sciences, Shiraz University, 71454 Shiraz, Iran

Marc Goosense
Leertendijk 8, 7683 SE Den Ham (Ov), The Netherlands

Tel: +98-711-2284572, Fax: +98-711-2280926



Abstract
The Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) is a multi-spectral imaging system with 14 bands in VNIR, SWIR, and TIR parts of the electromagnetic spectrum. ASTER false color and band ratio images were generated and used for discriminating the rock units of the Neyriz Ophiolite, SW Iran. The Neyriz Ophiolite complex lithologically consists of harzburgite tectonite, ultramafic unit including dunite, wehrlite, and websterite, cumulate unit composed of layered and massive gabbro, sheeted dykes, and pillow lavas. The Optimum Index Factor (OIF), based on total variance within bands and correlation coefficient between bands was used to rank all 3-band combinations of data covering the ophiolite complex. Three-band combinations with high total variance within bands and low correlation coefficient between bands will have high OIF. These combinations are expected to have the maximum extractable lithological information. Color composite of bands 7-3-1, as Red, Green, and Blue, and band ratio color composites of 4/7-4/1-2/3, and 4/7-3/4-2/1 were more useful for outlining lithological units.