Magma “conveyor belt” fueled supervolcanoes in the Indian Ocean for 30 MILLION years

The Indian Ocean was once home to ancient supervolcanoes that erupted for 30 million years, and researchers believe it was a magma “conveyor belt” that fueled the explosive events.

A team from Curtin University suggests that the conveyor belt created displacements in the sea floor that allowed molten lava to flow for millions of years, which are said to have started around 120 million years ago.

The long-term eruptions have occurred on the Kerguelen Plateau, located below the surface of the Indian Ocean, formed by an accumulation of magma and lava.

The team collected black basalt rocks from the sea floor and used a dating technique to determine the spread and amount of ancient magma and lava that was found on the mantle plume.

Data shows that the earth was covered with lava several miles thick and erupting at a rate of about seven inches each year.

As the Kerguelen Plateau is nearly the size of Western Australia, the eruption rate is equivalent to filling 184,000 Olympic-sized pools to the brim with lava each year – the total duration of the eruption is 5.5 trillion full pools of lava.

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The research was led by Qiang Jiang, a graduate student at Curtin’s School of Earth and Planetary Sciences, who said: “ Extremely large accumulations of volcanic rocks – known as large volcanic provinces – are very interesting to scientists because of their linkages. with mass extinctions, rapid climatic perturbations and the formation of mineral deposits “.

Jiang and his team collected rocks from the sea floor and used the argon-argon dating technique to find out the date of the lava flows.

Argon-argon dating is a radioisotope method that uses the decay of a potassium isotope and is considered “the most versatile, precise and accurate tool” when studying volcanic materials.

The seven-inch volume per year continued for 30 million years, making the Kerguelen Plateau home to the longest continuously erupting supervolcanoes on Earth.

However, the team found that eruption rates dropped dramatically around 90 million years ago, and the reason has not yet been determined.

“From that point on, there has been a slow but steady outflow of lava that has continued to this day, including the 2016 eruptions associated with the Big Ben volcano on Heard Island, Australia’s only active volcano,” he said. said Jiang.

Co-researcher Dr Hugo Olierook also explained that following the breakup of the supercontinent Gondwana, which formed Australia, India and Antarctica, the massive plateau “ began to form atop a mushroom-shaped mantle, called the mantle plume. , as well as long deep sea, mid-ocean mantle crests. “

“The volcanism lasted so long because the magmas caused by the mantle plume continually flowed through the mid-ocean ridges, which subsequently acted as a channel or” magma conveyor belt “for over 30 million years.

“Other volcanoes would stop erupting because, when temperatures cool, the channels are blocked by” frozen “magmas.

“For the Kerguelen plateau, the mantle plume acts as a Bunsen burner which continued to melt the mantle, resulting in an extraordinarily long period of eruptive activity.”