Scientists have shed new light on the timing and probable cause of major volcanic events that occurred millions of years ago and caused climatic and biological upheavals that resulted in some of the most devastating extinction events in Earth’s history.
Surprisingly, the new research, published today in the leading international journal Science Advances, suggests that a slowdown in the movement of continental plates was the critical event that allowed magma to rise to the Earth’s surface and produce the devastating chain impacts.
Earth’s history has been marked by major volcanic events, called Large Igneous Provinces (LIPs), the largest of which caused major increases in atmospheric carbon emissions that warmed the Earth’s climate, brought about unprecedented changes in ecosystems and caused mass extinctions on land and in the oceans.
Using chemical data from ancient sandstone deposits obtained from a 1.5km deep well in Wales, an international team led by scientists from Trinity College Dublin’s School of Natural Sciences was able to link two key events of approximately 183 million of years ago (the Toarcian period).
The team found that this time period, characterized by some of the most severe climatic and environmental changes ever recorded, coincided directly with the occurrence of large volcanic activity and the release of greenhouse gases in the southern hemisphere, in what is today. known as southern Africa. , Antarctica and Australia.
Upon further investigation, and most importantly, the team’s plate reconstruction models helped them uncover the key fundamental geological process that appeared to control the timing and initiation of this volcanic and other large-scale event.
Micha Ruhl, assistant professor at Trinity’s School of Natural Sciences, led the team. He said:
Scientists have long thought that the initiation of molten volcanic rock, or magma, from the depths of the Earth’s interior, like mantle plumes, was the instigator of such volcanic activity, but new evidence shows that the normal continental plate movement rate of several centimeters per year effectively prevent magma from penetrating into the Earth’s continental crust.
“It appears that it is only when the speed of continental plate movement slows near zero that magmas from mantle plumes can actually make their way to the surface, causing major volcanic eruptions of large igneous provinces and related climatic perturbations and mass extinctions. .
“Basically, further evaluation shows that a reduction in continental plate motion likely controlled the initiation and duration of many major volcanic events throughout Earth’s history, making it a fundamental process in controlling climate evolution and of life on the earth’s surface throughout the history of this planet ”.
The study of past events of global change, such as in the Toarcian, allows scientists to untangle the different processes that control the causes and consequences of global carbon cycle change and constrain the fundamental processes of the earth system that control points of no return. in the Earth’s climate system.
The research was conducted within the Early Jurassic Earth System and Timescale (JET) project of the International Continental Drilling Program (ICDP) and financially supported by the SFI Research Center in Applied Geosciences (iCRAG), the Environmental Research Council Natural History of the United Kingdom (NERC), the National Science Foundation China and the EU Horizon 2020 program.
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