The Indian Subcontinent: Its Tectonics

Abstract

A new geological and tectonic map of the India Subcontinent is presented with a brief description of its various elements. The map cover parts of India, Bhutan, Nepal, Sri Lanka, Bangladesh, Myanmar, and Pakistan and some of the offshore regions. The Extra-Peninsular region includes the Cenozoic Himalayan Orogen in Pakistan, India Nepal, Bhutan and its possible extension into Myanmar. This belt is separated fronm the Peninsular region by the vast late Cenozoic-Pleistocene Indo-Gangetoc-Brahmaputra Basin. The Peninsular India is mostly composed of six Archean-Proterozoic cratonic nuclei with indications of Hadean elements in Singhbhum. Proterozoic mobile belts surround these nuclei; hence the peninsular part might have been a single continent till end of Proterozoic. Deformation and metamorphism gradually decreased in their intensity, when vast Proterozoic sedimentary basins evolved over the Indian cratons and mobile belts unconformably. Paleo-Mesozoic rifts created the coal-bearing Gondwana basins, followed by marine transgressions before the onset of extensive Deccan volcanic eruptions in the western parts of the continent. Renewed northward movement of main Gondwan fragment as the part of the Indian Plate and its convergence with the Asian Plate caused the closure of the Tethyan Ocean in the north along the Indus-Tsangpo Suture Zone and evolution of the Himalayan Orogen during the Cenozoic when northern Indian margin was remobilized, deformed and metamorphosed. Uplift, exhumation and erosion of this mountain caused vast transportation of sediments in the Himalayan foreland basins and the Indo-Gangetic-Brahmaputra Basin. Northward movement of the Indian Plate was partitioned into dextral transpresional tectonics and eastward subduction in the Myanmar-Andaman. Keywords: