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Alteration identification by hyperspectral remote sensing in sisorta gold prospect (Sivas-Turkey)

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2009
Yetkin, Erdem
Imaging spectrometry data or hyperspectral imagery acquired using airborne systems have been used in the geologic community since the early 1980’s and represent a mature technology. The solar spectral range 0.4–2.5 μm provides abundant information about hydroxyl-bearing minerals, sulfates and carbonates common to many geologic units and hydrothermal alteration assemblages. Satellite based Hyperion image data is used to implement and test hyperspectral processing techniques to identify alteration minerals and associate the results with the geological setting. Sisorta gold prospect is characterized by porphyry related epithermal and mesothermal alteration zones that are mapped through field studies. Image specific corrections are applied to obtain error free image data. Extensive field mapping and spectroscopic survey are used to identify nine endmembers from the image. Partial unmixing techniques are applied and used to assess the endmembers. Finally the spectral correlation mapper is used to map the endmembers which are kaolinite, dickite, halloysite, illite, montmorillonite and alunite as clay group and hematite, goethite and jarosite as the iron oxide group. The clays and iron oxides are mapped with approximately eighty percent accuracy. The study introduces an image specific algorithm for alteration minerals identification and discusses the outcomes within the geological perspective.