Diamantina Fracture Zone
The Diamantina Fracture Zone is an area of the south-eastern Indian Ocean seafloor. It has a range of ridges and trenches. It lies to the south of the mideastern Indian Ocean features of the Wharton Basin and Perth Basin, and to the south west of the Naturaliste Plateau.
Being parallel to the Southeast Indian Ridge, Diamantina Fracture Zone is not a real fracture zone in the sense of plate tectonics, but rather an escarpment, separating two oceanic plateaus. In fact its extension to the west is called Diamantina Escarpment. This is the southern border of the Broken 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.
The Diamantina Deep is the zone's deepest location, sited 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 western side of the Diamantina Fracture Zone at is another, larger pit, named Dordrecht Hole, with a north-south extent of 50 km. The 2012 ETOPO1 Global Relief Model states maximum depth is 7,079 m (23,225 ft) at . Dordrecht was the name of a vessel of the Dutch East India Company, which explored the Australian west coast in 1619 and discovered the Houtman Abrolhos.
2019 ultra-deep-sea lander descent
To resolve the debate regarding the deepest point of the Indian Ocean the Diamantina Fracture Zone was surveyed by the Five Deeps Expedition in March 2019 by the Deep Submersible Support Vessel DSSV Pressure Drop, equipped with a Kongsberg SIMRAD EM124 multibeam echosounder system. Using the multibeam echosounder system and direct measurement by an ultra-deep-sea lander a maximum water depth of 7,019 m (23,028 ft) ±17 m (56 ft) at for the Dordrecht Deep was recorded. This is shallower than previously thought when historically measured by other, less precise, methods. The gathered data will be donated to the GEBCO Seabed 2030 initiative. The survey was part of the Five Deeps Expedition. The objective of this expedition is to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019.
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