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.

Escarpment

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.

Exploration

Diamantina Fracture Zone was first detected by and RV Argo in 1960. It is named after, which did further exploration in 1961.

Bathymetry

Based on surveys in the year 1960, the Diamantina Deep was considered by the General Bathymetric Chart of the Oceans Gazetteer to be the deepest point of the Indian Ocean with over depth at the position.
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 ± at for the Dordrecht Deep was recorded. Later analysis confirmed that the Dordrecht Deep with an extent of 80 × 95 km and a maximum depth of about at was the deepest location in the fracture zone. At the position of the Diamantina Deep, the water depth was only. This was shallower than previously thought, and confirmed that the Sunda Trench, rather than the Diamantina Fracture Zone, contains the deepest point in the Indian Ocean. The gathered data will be donated to the GEBCO Seabed 2030 initiative. The expedition aimed to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019, at which it was successful.
The shallowest point in the area is the 1125-metre point in the Broken Ridge close to Ninety East Ridge.