Which ocean contains the Ninety East Ridge?

Which ocean contains the Ninety East Ridge? The answer is the Indian Ocean.

The Ninety East Ridge is a long submarine rise on the floor of the Indian Ocean. It follows a course roughly parallel to the 90th meridian east, extending from the Bay of Bengal southward toward the Southeast Indian Ridge. Its name is geographic: “Ninety East” refers to its near alignment with 90°E longitude, not to a distance or depth.

The ridge is approximately 5,000 kilometres long and helps divide the Indian Ocean into western and eastern sectors. Much of it is buried or partly obscured by sediment in the north, especially beneath the Bengal Fan, one of the world’s largest submarine sediment fans.

Geologists have used basalt samples, magnetic data and seismic studies to investigate its origin. It was long associated with hotspot volcanism, but evidence of earthquakes and crustal deformation has also led scientists to describe the central Indian Ocean as a broad boundary zone between the Indian and Australian plates. It is therefore both a geographic feature and a clue to plate-motion history.