The Deccan Traps, India (Part 2): Its geomorphology and stratigraphy

Mugdha Chimote (India) Fig. 1. The natural arch/bridge at Ahmednagar, Maharashtra (see text box below). The Deccan Traps occupy approximately 25% of the total of peninsular India, that is, the triangular shaped landscape of southern India. They traverse the states of Maharashtra, Karnataka, Madhya Pradesh, and Gujarat. The Deccan Traps are currently believed to occupy about 500,000km2 of northwest peninsular India. It is estimated that the total exposure prior to erosion (including the region beneath the Arabian Sea) is of the order of 15 million square kilometres (Krishnan, 1956) or even up to 18 million square kilometres (Todal and Eldham, 1999). The differences in estimations of the total area of the Deccan Traps resulted from the fact that, an unknown area of the Deccan Volcanic Province (DVP) was rifted away as the Cambay rift system moved south and the Seychelles-Mascarene Plateau, along with part of the DVP, migrated to the west. The earliest basaltic eruptions took place along the north-western margins of the Indian continent, that is, in the Nashik-Narmada region. Later lava successions were emplaced on the southern flank of the evolving volcanic edifice as India migrated northwards over the plume head. The last of the flows were erupted in the southern DVP near Belgaum in Karnataka. As a result, the thickness of the flows gradually reduces from north-western to southern region of Indian subcontinent. Given the massive extent and volumes of Deccan Basalts, extensive studies have been carried out over the years to better understand the petrography, geochemistry, … Read More