Hydrothermal alteration mapping using EO-1 Hyperion hyperspectral data in Kösedağ, Central-Eastern Anatolia (Sivas-Turkey)

The Kösedağ region, is located in Central-Eastern Anatolia, contains a lot of base metals (Pb–Zn, Cu) and Au occurrences. The region is explored by numerous mining companies and MTA. In this research, hydrothermal alteration mapping by hyperspectral Hyperion satellite data was carried out to contribute to these explorations in a part of the region. Hydrothermal alteration is one of the initial steps in the exploration of such metallic occurrences. This study area was chosen to test the accuracy of the hyperspectral data results with those of field and laboratory study results. The in situ alteration map was prepared during field surveys and numerous samples analyses. These samples were investigated by microscopy and XRD examinations. The minerals which are belonging to argillic, sericitic, propylitic, and FeOx (iron oxide) hydrothermal alterations were determined. These minerals were checked and confirmed on the surfaces of altered samples by using ASD fieldspec 4 hi-res. The mixture tuned matched filtering (MTMF), which is one of the widely used spectral classification methods, was applied on the Hyperion data to determine the distributions of these alteration minerals in the study area. The results have shown that the comparison of field and laboratory studies and MTMF results coincided with an overall accuracy of over 86% and a kappa coefficient of 0.80. The alteration map has been generated using the MTMF method, has been the first hyperspectral research of the hydrothermal alteration mineralogy in the region. Consequently, the generated map can be used as a basic alteration map during exploration studies of hydrothermal base metal mineralizations in the region.