Diamantina Fracture Zone Ridge Plateau. All these features are mirrored by corresponding topography on the other side of the Southeast Indian Ridge. Broken Ridge Plateau was formed at the ridge together with the Kerguelen Plateau. Diamantina Fracture Zone was first detected by and RV Argo in 1960. It is named after , which did further exploration in 1961. The Diamantina Deep is the zone's deepest location, located about 1 125 km West-South-West of Perth, Western Australia, at . This is not the deepest point in the Indian Ocean: the CIA's Physical Map of the World lists the Java Trench as such. On the
South Sandwich Trench South Sandwich Trench The South Sandwich Trench is a deep arcuate trench in the South Atlantic Ocean lying 100 km to the east of the South Sandwich Islands. The trench is produced by the subduction of the southernmost portion of the South American Plate beneath the small South Sandwich Plate. The South Sandwich Islands constitute a volcanic island arc which results from this active subduction. Mount Belinda on Montagu Island is an active volcano. It is the deepest trench of the Southern Atlantic Ocean, and the second deepest of the Atlantic Ocean after the Puerto Rico Trench. The trench is