International research led by Curtin University geologists has found that a volcanic province in the Indian Ocean erupted for 30 million years, fuelled by a constantly moving ‘conveyor belt’ of magma.
It’s believed this magma ‘conveyor belt’, created by shifts in the seabed, continuously made space available for the molten rock to flow for millions of years, beginning about 120 million years ago.
Research lead Qiang Jiang, a PhD candidate from Curtin’s School of Earth and Planetary Sciences, said the studied volcanoes were in the Kerguelen Plateau, located in the Indian Ocean about 3000km south-west of Fremantle.
“Extremely large accumulations of volcanic rocks, known as large volcanic provinces, are very interesting to scientists due to their links with mass extinctions, rapid climatic disturbances and ore deposit formation,” Mr Jiang said.
“The Kerguelen Plateau is gigantic, almost the size of Western Australia. Now imagine this area of land covered by lava, several kilometres thick, erupting at a rate of about 20cm every year.
“Twenty centimetres of lava a year may not sound like much but, over an area the size of Western Australia, that’s equivalent to filling up 184,000 Olympic-size swimming pools to the brim with lava every single year.
“Over the total eruptive duration, that’s equivalent to 5.5 trillion lava-filled swimming pools.
“This volume of activity continued for 30 million years, making the Kerguelen Plateau home to the longest continuously erupting supervolcanoes on earth.”
Co-researcher Dr Hugo Olierook, also from Curtin’s School of Earth and Planetary Sciences, said such a long eruption duration required very peculiar geological conditions.
“After the partial breakup of the supercontinent Gondwana, into the pieces now known as Australia, India and Antarctica, the Kerguelen Plateau began forming on top of a mushroom-shaped mantle upwelling, called a mantle plume, as well as along deep sea, mid-oceanic mantle ridges,” Dr Olierook said.
“The volcanism lasted for so long because magmas caused by the mantle plume were continuously flowing out through the mid-oceanic ridges, which successively acted as a channel, or a ‘magma conveyor belt’ for more than 30 million years.”
Research co-author, Professor Fred Jourdan, director of the Western Australia Argon Isotope Facility at Curtin University, said the team used an argon-argon dating technique to date the lava flows, by analysing a range of black basaltic rocks taken from the bottom of the sea floor.
- The research paper, Longest continuously erupting large igneous province driven by plume-ridge interaction was published in Geology and can be found online here.