Abstract
The mafic and ultramafic rocks of Mettupalayam belong to the southern granulite terrain of India, which is concomitant with vital economic resources. The advantage of Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) data for mapping the litho units are exploited well here for differentiating the rock units with the aid of band combination (1, 3, 6), principal component analysis (5, 1, 6) and band ratioed band combination (2/3, 3/2, 1/5 and (9–8)/1, (8–6)/2, and (9–6)/3). As part of the field study, the collection of samples and ground control points were carried out and in addition to that, the generation of laboratory reflectance spectra for samples was achieved. The Spectral Angle Mapper (SAM) and Support Vector Machine (SVM) were performed using ASTER data with the aid of spectra obtained from the laboratory conditions to demarcate the abundance of mafic and ultramafic rocks of the area. The XRF method was used to retrieve the major oxides of the field-collected samples and the spectral absorption characters are validated with it. The results show a vibrant interpretation of the litho units.
Highlights
Southern Granulite Terrain (SGT), the prime example of high-grade metamorphic terrain situated in southern peninsular India consists of a group of crustal blocks namely Madurai, Trivandrum, Madras, Nilgiri, Salem, and Coorg (Collins et al 2014, Santosh 2020)
The 20 field samples collected from the different locations in and around Mettupalayam were scrutinized and three representative samples of mafic and ultramafic were selected
The highest reflectance is found in the band 1 of ASTER, against an absorption at 600 nm in red bands corresponding to the VNIR
Summary
Southern Granulite Terrain (SGT), the prime example of high-grade metamorphic terrain situated in southern peninsular India consists of a group of crustal blocks namely Madurai, Trivandrum, Madras, Nilgiri, Salem, and Coorg (Collins et al 2014, Santosh 2020). The ingenuity and evaluation of such kinds of resources are important and there is a need for sophisticated and advanced techniques to map the litho units in a time and cost-effective manner. In this regard, remote sensing can give tremendous results in mapping the abundance of rocks with the integrative techniques of spectral characterization as well as image processing (Abrams & Hook 1995, Duuring et al 2012).
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