<P> The Indian Ocean is the third largest of the world's oceanic divisions, covering 70,560,000 km (27,240,000 sq mi) (approximately 20% of the water on the Earth's surface). It is bounded by Asia on the north, on the west by Africa, on the east by Australia, and on the south by the Southern Ocean or, depending on definition, by Antarctica . It is named after the Indian subcontinent . The Indian Ocean is known as Ratnākara (Sanskrit: रत्नाकर), "the mine of gems" in ancient Sanskrit literature, and as Hind Mahāsāgar (Hindi: हिन्द महासागर), in Hindi . </P> <P> The borders of the Indian Ocean, as delineated by the International Hydrographic Organization in 1953 included the Southern Ocean but not the marginal seas along the northern rim, but in 2000 the IHO delimited the Southern Ocean separately, which removed waters south of 60 ° S from the Indian Ocean, but included the northern marginal seas . Meridionally, the Indian Ocean is delimited from the Atlantic Ocean by the 20 ° east meridian, running south from Cape Agulhas, and from the Pacific Ocean by the meridian of 146 ° 55'E, running south from the southernmost point of Tasmania . The northernmost extent of the Indian Ocean is approximately 30 ° north in the Persian Gulf . </P> <P> The Indian Ocean covers 70,560,000 km (27,240,000 sq mi), including the Red Sea and the Persian Gulf but excluding the Southern Ocean, or 19.5% of the world's oceans; its volume is 264,000,000 km (63,000,000 cu mi) or 19.8% of the world's oceans' volume; it has an average depth of 3,741 m (12,274 ft) and a maximum depth of 7,906 m (25,938 ft). </P> <P> The ocean's continental shelves are narrow, averaging 200 kilometres (120 mi) in width . An exception is found off Australia's western coast, where the shelf width exceeds 1,000 kilometres (620 mi). The average depth of the ocean is 3,890 m (12,762 ft). Its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m (26,401 ft) deep; Sunda Trench has a depth of 7,258--7,725 m (23,812--25,344 ft). North of 50 ° south latitude, 86% of the main basin is covered by pelagic sediments, of which more than half is globigerina ooze . The remaining 14% is layered with terrigenous sediments . Glacial outwash dominates the extreme southern latitudes . </P>

What is the deepest point in the indian ocean