Abstract
In spite of the dominance of traditional mineral exploration methods that demand physical characterization of rocks and intense field work, remote sensing technologies have also evolved in the recent past to facilitate mineral exploration. In the present study, we have processed visible near infrared (VNIR) and shortwave infrared (SWIR) bands of Advanced space-borne thermal emission and reflection radiometer (ASTER) data to detect surface mineralization signatures in Mundiyawas - Khera area in Alwar basin, north-eastern Rajasthan, India using spectral angle mapper (SAM). The potential of SAM method to detect target under variable illumination condition was used to delineate galena, chalcopyrite, malachite etc. as surface signatures of mineralization. It was ensured that the identified surface anomalies were spectrally pure using pixel purity index. Spectral anomalies were validated in the field and also using X-Ray diffraction data. Spectral anomaly maps thus derived were integrated using weight of evidence method with the lineament density, geochemical anomaly, bouger anomaly maps to identify few additional potential areas of mineralization. This study thus establishes the importance of remote sensing in mineral exploration to zero in on potentially ore rich but unexplored zones.
Highlights
Copper is one of the most widely used metals in India and its usage is only to iron and aluminium in terms of volume
The Geological Survey of India (GSI) (2016) reported Cu mineralization within the Thanaghazi Formation is evidenced by the presence of malachite, chalcopyrite and bornite
spectral angle mapper (SAM) has widely been used in spectral remote sensing to map the surface expressions in all application fields (Van der Meer and Jong, 2003; Kodikara et al, 2015)
Summary
Copper is one of the most widely used metals in India and its usage is only to iron and aluminium in terms of volume. The Copper mineralization in Alwar District, Rajasthan, India has been recorded within the Kushalgarh, Sariska and the Thanaghazi Formations of the Ajabgarh Group (Mukhopadhyay, 2009). Presence of numerous old workings, huge mine dumps, slag heaps in the Jodhawas and Shyampura area in the Kushalgarh Formation within the biotite- marble and quartz- marble rocks and fine dissemination, stringers and small veins of mostly malachite are indications of Cu mineralization in the area (Heron, 1953; GSI, 2011, 2016). The Geological Survey of India (GSI) (2016) reported Cu mineralization within the Thanaghazi Formation is evidenced by the presence of malachite, chalcopyrite and bornite. According to Dr S K Wadhawan, deputy director general, GSI, "A 108.10-metre-thick copper mineralization from the Alwar basin of the north Delhi fold belt found.
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