Laboratory-based, field-based, and satellite-borne spectroscopy for lithological discrimination

Abstract

Spectroscopic analysis is carried out for lithological discrimination in a study area in the Pali and Ajmer districts of Rajasthan, western India using laboratory-based, field-based and space-borne data. We first explored the feasibility of the Landsat-8 (Operational Land Imager (OLI), Thermal Infrared Sensor (TIRS)) and Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) imagery for lithological mapping. Laboratory spectra of the samples of rocks exposed in the area were collected using FieldSpec3 spectroradiometer in the VNIR-SWIR region and resampled to the LANDSAT 8 and ASTER spectral bands. The spectral angle mapper (SAM) algorithm was used to map the lithologies using the resampled laboratory spectra as references. The resulting map was validated based on field geological mapping. Fourier Transform Infra-Red (FTIR) spectroscopy of selected rock samples was carried out to correlate spectral absorption features in the TIR-IR regions with the vibrational energy.