The slowing of the movement of the tectonic plates controlled the timing of Earth’s major volcanic events

Scientists have shed new light on the timing and likely cause of major volcanic events that occurred millions of years ago and caused such 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 scientific advancessuggests that a slowing of the movement of the tectonic plate was the critical event that allowed magma to rise to the Earth’s surface and trigger the devastating effects.

Earth’s history has been marked by major volcanic events called large volcanic provinces (LIPs) – the largest of which have led to sharp increases in atmospheric carbon emissions, warming Earth’s climate, causing unprecedented changes in ecosystems, and mass extinctions land and inward led the oceans.

Using chemical data from ancient mudstone deposits recovered from a 1.5 km deep borehole in Wales, an international team led by scientists from Trinity College Dublin’s School of Natural Sciences has been able to identify two key events around 183 million years ago (the Toarcian period) with each other. .

The team discovered that this period, marked by some of the most severe climate and environmental changes on record, coincided directly with the occurrence of major volcanic activity and the associated release of greenhouse gases in the southern hemisphere, present-day Southern Africa, Antarctica and Australia.

Upon further investigation – and more importantly – the team’s plate reconstruction models helped them discover the key underlying geological process that appeared to drive the timing and onset of this volcanic event and other large-scale events.

Micha Ruhl, an assistant professor at Trinity School of Natural Sciences, led the team. He said: “Scientists have long assumed that the onset of the rise of molten volcanic rock, or magma, from deep within the Earth’s interior as mantle clouds was the trigger for such volcanic activity, but the new evidence shows that the normal rate of continental plate motion exceeds that of several centimeters per year effectively prevents magma from entering the continental crust.

“It appears that magmas from mantle plumes can only effectively surface when the rate of continental plate motion slows to near zero, leading to large volcanic eruptions in magmatic provinces and the attendant climate disturbances and mass extinctions.

“Critically, further assessment shows that a reduction in continental plate movement likely controlled the onset and duration of many of the most important volcanic events throughout Earth’s history, making them a fundamental process in controlling the evolution of climate and life.” on the surface of the earth throughout history makes this planet.”

Studying past global change events, such as in the Toarcian, allows scientists to unravel the various processes driving the causes and consequences of global carbon cycle changes and constrain fundamental Earth-system processes driving tipping points in the Earth’s climate system.