“…At first, iron oxides BRs 3/1 and 4/2 for Landsat TM/ETM+ and OLI8, respectively, were applied in order to highlight iron oxides by the presence of bright pixels (Sabins, 1999). The iron oxides BR is useful for detecting ferric iron (Fe 3+ ) oxides such as hematite and goethite (Imbroane et al, 2007;Hung, 2013;Pour et al, 2019;Rockwell, 2013;Soe et al, 2005;Traore et al, 2020). At second, the BRs 5/7 and 6/7 for Landsat TM/ETM+ and OLI8, respectively, were applied in order to highlight hydroxyl-bearing minerals such as clay minerals (kaolinite, montmorillonite and alunite) by the presence of bright pixels (Clark, 1999;Hung, 2013;Imbroane et al, 2007;Sabins, 1999;Soe et al, 2005).…”