South Australian Basin

South Australian Basin

 

an underwater basin in the southeastern part of the Indian Ocean. The South Australian Basin is bounded by the continental slope of Australia in the north and northeast, by the underwater Mill Rise (or South Tasmania Ridge) in the east, and by the Australian Antarctic Rise in the south. Its western boundary is a hypothetical line extending from Leeuwin Cape to 115° E long. The South Australian Basin is about 2,400 km long and 800 km wide. The eastern part is a flat abyssal plain, while the sea floor of the northwestern part is broken by deep trenches and ridges. The maximum depth is 6,024 m (according to some data, 5,853 m). The sediments are primarily red clay, with ferromanganese concretions in some places and foraminiferal oozes along the northern and eastern margins.