Airborne hyperspectroscopy using AVIRIS- NG data for detecting surface signatures of kimberlite and kimberlite clan of rocks in Bundelkhand Craton, India

Abstract

Abstract We have utilized spectral bands of Advanced Visible Infrared Imaging Spectroradiometer Next Generation sensor (AVIRIS-NG) to identify surface signatures of new kimberlite. The main focus of the work is to identify the surface signatures of probable kimberlite occurrence and to substantiate these surface signatures as the prospective areas of detailed exploration. Since, all the discovered kimberlites were reported within ferruginous quartzite (Fe-quartzite), we prepared an AVIRIS-NG image composite to demarcate the spatial extension of ferruginous quartziteThe AVIRIS-NG image spectrum of a known kimberlite was also used, as a reference, to identify the surface signatures of new kimberlite within Fe-quartzite. We applied matched filtering and adaptive coherence estimator algorithms to detect surface signatures of kimberlite. The detected surface anomalies of kimberlite in each spectral map are consistent in shape, number and spatial extent. Subsequently, we integrated these maps into a unified surface anomaly map of kimberlite using multiplication operator for identifying the surface anomalies of kimberlite. We observed that the image spectra of these surface anomalies are similar to the laboratory and image spectra of a known pipe. Most of the detected new anomalies are circular and associated with geological lineaments delineated in the residual gravity anomaly map derived from the EIGEN 6C4 gravity model. The surface anomalies of kimberlite, identified in this research, substantiate the importance of detected anomalies for further exploration.