How old is the Indian Ocean?

Written and fact-checked by The Editors of Encyclopaedia Britannica

The Indian Ocean is the smallest, geologically youngest, and physically most complex of the world’s three major oceans (the others being the Pacific and Atlantic). Although it first opened some 140 million years ago, almost all of the Indian Ocean basin is less than 80 million years old. By 36 million years ago the Indian Ocean had taken on its present configuration.