Scientists have shed new light on the timing and possible cause of major volcanic events that occurred millions of years ago and caused climate and biological disruptions that led to some of the most devastating extinction events in Earth’s history.
Surprisingly new research published today in the journal science progressindicates that the slowing down of the continental plates was the critical event that enabled magma to rise to Earth’s surface and produce devastating effects.
Earth’s history has been marked by major volcanic events, called Large Volcanic Provinces (LIPs) – the largest of which have caused significant increases in carbon emissions to the atmosphere that warmed the Earth’s climate, led to unprecedented changes to ecosystems, and led to Earth mass extinctions and in the oceans.
Using chemical data from ancient mud deposits obtained from a 1.5 kilometer deep well in Wales, an international team led by scientists from Trinity College Dublin for Natural Sciences was able to link two major events about 183 million years ago (the Tuarcian period).
The team discovered that this time period, which was marked by some of the harshest climatic and environmental changes ever, directly coincided with significant volcanic activity and associated greenhouse gas emissions in the Southern Hemisphere, in what is today South Africa. , Antarctica and Australia.
Upon further investigation – and more importantly – the team’s plate reconstruction models helped them discover the underlying geologic process that seemed to control the timing and onset of this volcanic and other mega-events.
The team was led by Misha Roll, associate professor at Trinity College of the Natural Sciences. He said:
Scientists have long believed that the beginning of the rise of molten igneous rock, or magma, from the depths of the Earth’s interior, such as mantle plumes, was the instigator of such volcanic activity, but new evidence shows that the natural rate of movement of continental plates of many centimeters per year effectively prevents magma from penetrating Earth’s continental crust.
“It appears that only when the velocity of continental plate movement slows to nearly zero can magma from the mantle plumes effectively make its way to the surface, causing large eruptions in igneous provinces and associated climate disturbances and mass extinctions.
“Importantly, further assessment shows that declines in continental plate movement likely have governed the onset and duration of many major volcanic events throughout Earth’s history, making them an essential process in controlling the evolution of climate and life on Earth over the course of the Earth’s history. this planet.”
Studying past global change events, such as in the Toarcian, allows scientists to separate the different processes that control the causes and consequences of changing the global carbon cycle and constrain the underlying Earth system processes that control tipping points in the Earth’s climate system.
The research was conducted as part of the Early Jurassic Earth System and Time Scale (JET) project of the International Continental Drilling Program (ICDP), and with financial support from the SFI Research Center in Applied Geosciences (iCRAG), the UK’s Natural Environment Research Council (NERC) and the National Science Foundation In China and the European Union’s Horizon 2020 programme.