Crustal magnetisation-model of the Indian subcontinent through inversion of satellite data

Abstract

An apparent magnetisation-model of the Indian subcontinent and the adjoining regions has been obtained through the inversion of MAGSAT total field (scalar) and vertical field data. A staggered 4° × 4° grid pattern with a constant continental crustal thickness of 40 km yielded magnetisation values over a 2° × 2° grid. Over the major part of the Indian subcontinent, the magnetisation picture brings out a prominent “high” sandwiched between the Eastern Ghats and the main boundary fault of the Himalayas. In contrast, the identity of the Western Ghats, comprising mainly Deccan Traps, is missing. While a distinct magnetisation “low” is observed over the known hot-spot region of the Saurashtra Peninsula, two magnetisation “highs”—one over the Shillong Massif and the other over the Central part of India covering Aravallis and the Bundelkhand Massif—are obtained. Interestingly, even at a height of 400 km, the well known Narmada-Son lineament is clearly reflected in the total intensity map as well as in the corresponding magnetisation map. The Bay of Bengal and the Himalayas ara characterised by magnetisation “lows”.