Image Processing of Landsat-8 OLI Satellite Data for Mapping of Alkaline-Carbonatite Complex, Southern India

Abstract

The alkaline-carbonatite igneous intrusion occupies a very less aerial extent on the earth's surface; however, it is an important source rock for REE, LILE and radioactive elements. The origin of the alkaline-carbonatite suite is always related to tectonic settings such as continental drift and suture zone. In this context, the Samalpatti and Sevathur alkaline-carbonatite complex is an area of interest among various geoscientists. The moderate resolution Landsat-8 OLI satellite data is digitally processed using ENVI 5.3 image processing software for the interpretation of various lithology in the terrain. The Samalpatti-Sevathur complex is covered by different rock types including syenite, pyroxenites, dunite, carbonatite, and epidote hornblende gneiss. The carbonatites are emplaced as elongated bodies, dykes and scattered nodules in ultramafic formation. The mapping of ultramafic formations is important, since it contains carbonatite emplacement in the complex. The seven band OLI data covered under the visible, near infrared, and shortwave infrared spectrum were processed for the generation of colour composite images, band ratios, principle component analysis (PCA) images, and support vector machine (SVM) classified output. The digitally processed satellite images are useful in the interpretation of different rock types, particularly the ultramafic formation. Out of various outputs, the FCC, the composite image B652, colour composite images from ratio output, PCA composite images in RGB filters, and SVM classified image are suitable for interpretation of different lithology in the terrain.