Türkiye Jeoloji Bülteni

Investigation of the hydrothermal alterations by using Landsat 7 ETM+ and ASTER images in Tekkale-Yusufeli (Artvin-NE Turkey) surroundings

Abstract: The study area is located in the eastern part of Pontides metallogenic belt. The metallogenic belt of the easternPontides has a significant potential in terms of ore formations such as volcanic massive sulphide (VMS),porphyry Cu-Mo, epithermal, skarn, chromite. In this study, hydrothermal alteration features associated with VMS-type ore formations have investigated by using Landsat 7 ETM+, ASTER images and ASD Fieldspec Prospektrometer. To determine the hydrothermal alteration minerals, band ratio method have been applied to bothimages. Also, Landsat 7 ETM + and ASTER satellite images have been analyzed by using respectively CrostaTechnique and matched filtered (MF) methods, and the hydrothermal alteration zones associated with the oreformations such as argillic alteration, silicification, ironoxide in region have been mapped. The results obtainedthrough image analysis have been evaluated by using especially Geographic Information Systems (GIS)environment and at last, the potential target areas of hydrothermal alterations to be important in term of VMStype ore deposits have been determined. In particular, an extensive areas of argillic alteration have beendistinguished on Upper Cretaceous aged dacitic volcanic units. Also, the anomalies areas of alunite/kaoliniteand silicification have appeared as spatially associated with argillic alteration in some region. The direction ofapproximately NE-SW of determined hydrothermal alterations have been seen as a characteristic feature.