A new study has shown that huge magma eruptions can initiate deeper below Earth’s surface than previously thought. Such flood basalt eruptions have caused many global climate changes and mass extinction events in the past.
Until now, the largest flood basalt eruptions were believed to be possible only in regions where the continental tectonic plates are usually thin, so the deep mantle material is able to rise close to the Earth’s surface. In such low-pressure environments, melting of the hot mantle can generate very large amounts of magma.
“We became curious about the occurrence of most flood basalts in regions where the African and Antarctic tectonic plates are thick rather than thin,” said Dr. Arto Luttinen, leader of the University of Helsinki team. “Moreover, we found that many flood basalts that have rare earth element compositions, suggesting high-pressure formation conditions, are actually located in thin regions of the tectonic plates.”
https://phys.org/news/2022-11-magma-erupt-deeper-sources-earlier.html