Regional Scale Alteration Mineral Mapping using ASTER Imagery in Sparsely Vegetated Terrain: a case study from Eastern Part of South Purulia Shear Zone, India

Abstract: The use and recognition of remote sensing technique for geological application has been increased manifold in the last two decades. Although greater achievements were made in public availability of data, sensor resolution such as revisiting time, spatial resolution and temporal resolution, mineral exploration in unexplored vegetated region is still remain challenging. The vegetation present in the terrain hiders the signature of the underlying geological material partially. Therefore, locating the potential zone for hydrothermal deposits becomes more difficult in such domain. The current work documented mineral mapping on a sparsely vegetated terrain, i.e., eastern part of South Purulia Shear Zone, India using ASTER imagery. It provides a comparative study of Band ratio and Directed Principal Component Analysis for alteration mineral mapping. The remotely derived results have been correlated and validated with field evidences and geomorphic features identified from the high resolution Geoeye imagery. Alteration zones are observed to developed parallel to the shear zone as small-scale discrete pockets. The DPC result has been interpreted in two different ways shows accuracy of 79.31% for ¼th standard deviation classification scheme, and 77.01% for band combination with thresholding and linear stretching techniques. Hydrothermal alteration zones identified from the study seeks further details study on alteration and mineralization.

Keywords: ASTER; Band ratio; Directed Principal Component Analysis; Alteration mapping; vegetated terrain