Kerguelen Plateau

The Kerguelen Plateau, also referred to as the Kerguelen–Heard Plateau, is an oceanic plateau and large igneous province situated on the Antarctic Plate in the southern Indian Ocean, located roughly to the southwest of Australia and comparable in size to South Africa. Extending over a considerable distance in a northwest–southeast direction, the plateau lies in deep water, with most of its expanse less than a certain depth below sea level. It rises substantially above the surrounding oceanic basins and covers a vast area, making it one of the largest igneous provinces globally.

A small portion of the plateau breaks the sea surface, forming the Kerguelen Islands, a French overseas territory, and the Heard and McDonald Islands, an Australian external territory, where intermittent volcanism continues. The plateau was generated by the Kerguelen hotspot, beginning with or following the breakup of Gondwana roughly 130 million years ago. Geologically, the plateau is separated from Australia by the Southeast Indian Ridge and from Africa by the Southwest Indian Ridge, which meet at the Rodriguez Triple Junction.

Its eastern margin north of the William Ridge is steep, formed during the separation between the Kerguelen Plateau and the Broken Ridge, a once-contiguous underwater volcanic plateau now located symmetrically across the Indian Ocean ridge. The southern margin is separated from the Australian–Antarctic Basin by the deep Labuan Basin. The Kerguelen hotspot has produced several widely dispersed large-scale structures over time, including the Southern, Central, and Northern Kerguelen Plateaus, the Elan Bank, the Broken Ridge, the Skiff Bank, and the Ninety East Ridge, as well as continental basalts such as the Bunbury Basalt and the Rajmahal Traps, linked to the opening of the eastern Indian Ocean.