Evaporite mineral mapping and determining their source rocks using remote sensing data in Sirjan playa, Kerman, Iran

In this research, evaporite minerals of Sirjan playa, Iran were mapped using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat 8 images. Spectral angle mapper (SAM) was applied to map evaporite minerals of the study area. Two kinds of reference spectra were used for classifying the images that consist of: (1) recorded reflectance spectra of evaporite minerals and (2) image-derived spectra which were acquired from images based on GPS coordinates of samples. Determination of evaporite minerals assessed by X-ray diffraction (XRD) on field samples which were collected in October 2015 when the lake was completely dry. After image classification, the overall accuracy of 95.27% for Landsat 8 images and 91.81% for ASTER images were achieved, respectively, using image-derived spectra. SAM classification using samples' spectra showed lower accuracy of 85.96 and 80.31% for ASTER and Landsat images, respectively. Therefore, the image-derived spectra produced better classification accuracy. For determining the main source of inflows of the sediments into the playa, drainage system of Sirjan basin, that was derived using digital elevation model, false color composite image, mosaic of old aerial photographs and map of evaporite minerals were used. It showed that the main source of inflows of the sediments to the playa is from volcanic and sedimentary rocks of Urumieh-Dokhtar mountains located in the north-east and eastern parts of the playa.