Ninety East Ridge

The northeastern side is named the Wharton Basin and ceases at the western end of the Diamantina fracture zone which passes to the east and almost to the Australian continent.

[4] Even more recent work with more samples gives a range of 82 to 37 million years ago[5]: 1178 This age progression has led geologists to theorize that a hotspot in the mantle beneath the Indo-Australian plate created the ridge as the plate has moved northward in the late Mesozoic and Cenozoic.

[5]: 1177  This results in the interpretation that at least two separate hotspots contributed and the Ninety East Ridge is predominantly a historic divergent plate boundary with eruptives from a deep mantle source.

In 2007, the RV Roger Revelle collected bathymetric, magnetic and seismic data together with dredge samples from nine sites along the ridge as part of an Integrated Ocean Drilling Program (IODP) site survey intended to examine the hotspot hypothesis for the ridge.

Preserved pollen and plant cuticle fragments have been found in boreholes drilled on the ridge.