Surprising discovery shows that a slowdown in continental plate movement controlled the timing of Earth’s largest volcanic events

Scientists have shed new light on the timing and likely cause of major volcanic events that occurred millions of years ago that caused such a climatic and biological upheaval that they triggered some of the most devastating extinction events in Earth’s history.

Surprisingly, the new research, published today in the journal scientific progresssuggests that a slowdown in continental plate movement was the critical event that allowed magma to rise to Earth’s surface and trigger the devastating domino impacts.

Earth’s history has been marked by major volcanic events called Large Igneous Provinces (LIPs) – the largest of which have led to major increases in atmospheric carbon emissions that have warmed the Earth’s climate, caused and led to unprecedented changes in ecosystems. to mass extinctions on land and in the oceans.

Using chemical data from ancient mudstone deposits obtained from a 1.5 km deep borehole in Wales, an international team led by scientists from Trinity College Dublin’s School of Natural Sciences was able to identify two major events from about 183 million years ago (the Toarcian period) together. .

The team found that this period, marked by some of the most severe climate and environmental changes ever recorded, coincided directly with the occurrence of major volcanic activity and associated greenhouse gas emissions in the Southern Hemisphere, in what is today known as southern Africa. , Antarctica and Australia.

On further exploration — and more importantly — the team’s plate reconstruction models helped them discover the key fundamental geological process that seemed to control the timing and onset of this volcanic event and others of great magnitude.

Micha Ruhl, assistant professor at Trinity’s School of Natural Sciences, led the team. He said:

Scientists have long believed that the onset of upwelling of molten volcanic rock, or magma, from deep within the Earth’s interior, like mantle plumes, was the instigator of such volcanic activity, but new evidence shows that the normal rate of continental plate movement of several centimeters per year effectively prevents magma from penetrating the Earth’s continental crust.

“It appears that only when the speed of continental plate movements slows to near zero can mantle plume magmas effectively make their way to the surface, causing major volcanic eruptions in the volcanic province and associated climatic disturbances and mass extinctions.

Crucially, further assessment shows that a reduction in continental plate movement likely controlled the onset and duration of many of the major volcanic events in Earth’s history, making it a fundamental process in controlling the evolution of the climate and life on the Earth’s surface throughout the history of this planet.”

The study of past events, such as in the Toarcian, allows scientists to unravel the various processes that control the causes and consequences of global carbon cycle change and the fundamental processes of the Earth system that control tipping points in Earth’s climate system. , to limit.

The research was conducted as part of the International Continental Drilling Program (ICDP) Early Jurassic Earth System and Timescale (JET) project, and was financially supported by the SFI Research Center in Applied Geosciences (iCRAG), the Natural Environment Research Council UK ( NERC), the National Science Foundation China and the EU Horizon 2020 program.

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