Comparative evaluation of airborne AVIRIS-NG and spaceborne PRISMA hyperspectral data in identification and mapping of altered/weathered minerals in Jahazpur, Rajasthan

Abstract

The present study addresses a comparative evaluation of airborne AVIRIS-NG and spaceborne PRISMA hyperspectral datasets for mapping hydrothermally altered minerals in Jahazpur town (25°25′23.37″N; 75°06′23.17″E) of Bhilwara district in southeastern Rajasthan. This area is located in Aravalli Craton which host notable base metal mineralization namely Rampura-Agucha, Pur-Banera and Rajpura-Dariba. The hyperspectral datasets were classified using spectral angle mapper which identified talc, soapstone, and kaolinite clay minerals in the study area. The samples were collected from the identified areas. Their spectral signature was compared with AVIRIS-NG, PRISMA, and USGS mineral spectral library and showed greater similarity in spectral absorption features. Conventional geological techniques such as thin section studies and XRD diffraction pattern analysis were carried out to validate the presence of minerals in the study area. Comparative analysis shows AVIRIS-NG and PRISMA sensor capability to identify altered/weathered minerals. The PRISMA dataset did not identify small surface exposure of talc deposit at the Padampura location due to its low spatial resolution (30 m) and SNR values. In contrast, AVIRIS-NG imagery successfully maps this exposure in the classified mineral map. The types of alteration in the area show formation of talc mineral from dolomite and argillic alteration resulting in kaolinite and montmorillonite formation. Therefore, airborne AVIRIS-NG proves its efficiency in mapping of relatively small surface exposure of altered minerals compared with the spaceborne PRISMA hyperspectral dataset.