Kerguelen hotspot

[7] However younger lavas towards the south east of the archipelago that are mainly found as dykes or plugs in these flood basalts and have ages between 10 and 6 million years.

[12] It is important to realise in the discussion below that the dates referred to were obtained over a period of about 50 years and those found by earlier work have been updated where appropriate as more samples analysed.

[13][8] The current location of this hotspot, if it exists, is hard to determine as there are areas of recent volcanic activity that might be associated with the still spreading Southeast Indian Ridge.

[14][15] One hundred and forty million years ago the present north-eastern aspect of India (Bengal), southern Western Australia and Princess Elizabeth Land portions of Antarctica were adjacent before Gondwana breakup.

[23] Present day structures such as the Elan Bank may have their placements due to ridge jumps at propagating rifts during the process of sea floor spreading.

[23] The oldest volcanic rocks assigned to the Kerguelen hotspot are now understood to have been erupted during the Early Cretaceous in the Comei large igneous province of southeastern Tibet from 145 million years ago.

[18] Between Western Australia and Gulden Draak Knoll on the floor of the Indian Ocean are the Naturaliste, Wallaby, and Zenith Plateaus that erupted between 130 to 117 million years ago,[29][27] now well separated from India.

The Seaward Dipping Reflectors, now at the southern end of the Kerguelen Plateau near Antarctica also formed in this period more than 126 million years ago.

[16] The Southern Kerguelen Plateau in the enlarging basin of the Indian Ocean was formed between 120 to 110 million years ago, [30] and was a much larger volume of basalt, consistent with a large igneous province.

[32] Eruptions also occurred during this period at what is now the Gulden Draak Knoll off Western Australia at 117 million years ago due to the subsequent tectonic plate motions.

[16] Multiple workers postulate that buried under about 5 km (3.1 mi) of sediments on the seafloor of the Bay of Bengal,[35] there is a continuation of the Ninety East Ridge with volcanics deposited about 90 million years ago.

This also could explain the more recent formation of the Amsterdam-Saint Paul Plateau, [34] which is aged at 10 million years ago and is to the south of present Southeast Indian Ridge,[16] but composition studies are inconsistent.