An underground magma 'conveyor belt' that has been moving towards the Earth's surface over millions of years has caused continuous eruptions of supervolcanoes over millions of years, according to new research.
The researchers say shifts in the seabed created channels through which magma could flow freely. This led to a long period of eruptions, lasting from about 122 million years ago to 90 million years ago; Exceptionally, considering that these types of streams usually exist for only 1-5 million years.
All this took place on the Kerguelen Plateau, which is now under the Indian Ocean. This is what is known as a large igneous province, a widespread accumulation of magma and lava.
“The extremely large accumulations of volcanic rocks – known as large volcanic provinces – are of great interest to scientists because of their association with mass extinctions, rapid climate change and the formation of ore deposits,” says geologist Qiang Jiang of Curtin University in Australia.
Jiang and colleagues used black basaltic rock samples taken from the sea floor, along with argon isotope dating, to determine the distribution and uplift of rock created by rising magma.
Over 30 or so years of vigorous activity, the Kerguelen Plateau has risen by about 20 centimeters per year, according to researchers. Through a giant rift – about three times the size of Japan – the lava effusion is equivalent to filling 184,000 Olympic-size pools with lava per year.
The Kerguelen Plateau has experienced such a long and sustained period of supervolcano activity due to its unique configuration, as studies show: a mantle plume combined with slowly spreading mid-ocean ridges that direct magma upward.
“The volcanism lasted so long because the magma flows caused by the mantle plume flowed continuously through the mid-ocean ridges that have consistently acted as a channel or 'magma conveyor belt' for over 30 million years,” says geologist Hugo. Olieruk from Curtin University.
This is a look at the history of our planet, and, of course, it helps us in the study of volcanic activity today – the more we know about how such systems can form and remain active, the better we can understand the interactions taking place right now. under the surface of the Earth.
“Research has implications for our understanding of magmatism on Earth and other planets.”
The research is published in the journal Geology.
