Guest editorial for the special issue 'Tectonics of Bay of Bengal and Arabian Sea with special emphasis on coastal and marine geohazards'

摘要

The Indian Ocean, the third largest of the world's oceans, is comprised of diverse and complex tectonic features. The Arabian Sea and the Bay of Bengal, bordering the Indian Peninsula on west and east, respectively, constitute the northwestern and northeastern parts of the Indian Ocean. The evolution of Indian Ocean and the present morphology and tectonics of the bordering continental margins are the consequence of the breakup of Eastern Gondwanaland and subsequent seafloor spreading between the constituent continents viz., Madagascar, Seychelles, India, Antarctica, and Australia, since the Early Cretaceous. There were three main episodes in the disintegration of Gondwanaland (Storey 1995). The rifting started during the Early Jurassic, when Gondwanaland separated into eastern and western parts, causing a seaway separating South America-Africa from Madagascar-Seychelles-India-Antarctica-Australia-New Zealand. The second stage occurred in Early Cretaceous, with South America separating from an African-Indian plate and African-Indian plate itself separating from the Antarctica. Finally, the third stage occurred in Late Cretaceous when Australia and New Zealand got separated from Antarctica. Around this time, Madagascar separated from India, and thelatter migrated northward.