Identification of alterations and geological structures related to hydrothermal deposits using various satellite image processing techniques (Case study: Northeast of Maku-Tabriz geological zone)

Today, remote sensing is one of the most important stages of exploration using satellite imagery to detect minerals. In this regard, it is important to study and recognize different and new methods because of increasing the probability of exploration and reducing the risk. Methods that, while simple and efficient, also reduce exploration costs. For remote sensing studies in the study area, after preparing the required information such as satellite images (images of Aster and Landsat 8 (OLI) satellites) and 1:100000 Siahhroud geological map, a database containing all the required information was formed. In order to use satellite images in exploratory studies, first the necessary preprocessors appropriate to the type of satellite used were implemented on the images. These predictions include Crosstalk Correction, Radiometric Correction, Atmospheric Correction, Geometric Correction, and Elimination of Vegetation Effect by the Vegetation Index (NDVI). Then, for separation and detection of mineralization control evidences including lithological type, geological structures, alterations (including argillic, phyllic, propylitic, silica and iron oxides) and lines from image processing methods such as band ratio (BR), false color combination (FCC), Selective principal component analysis (SPCA), Mixture Tuned Matched Filtering (MTMF), Directional and frequency filter (FFT) were used. Finally, the final maps of the alterations as well as the maps of the geological structures were prepared and the important areas affected by the alterations were identified.