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 led to some of the most devastating extinction events in history of the Earth
Strikingly, the new research, published today in the journal Science Advances, suggests that the slowing of continental plate movement was the critical event that allowed magma to rise to Earth’s surface and produce devastating impacts.
Earth’s history has been marked by large volcanic events, called large igneous provinces (LIPs), the largest of which have caused significant increases in carbon emissions into the atmosphere that have warmed Earth’s climate, caused unprecedented changes in ecosystems and have caused mass extinctions on land and in the oceans.
Using chemical data from ancient mud deposits obtained from a 1.5km-deep borehole in Wales, an international team led by scientists from the School of Natural Sciences at Trinity College Dublin was able to link two events key from about 183 million years ago (the Toarcian period).
The team discovered that this time period, which was characterized by some of the most severe climate and environmental changes in history, directly coincided with the occurrence of significant volcanic activity and the emission of greenhouse gases greenhouse associated with the southern hemisphere, in what is now known as southern Africa. , Antarctica and Australia.
In further research, and more 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 and other volcanic events of great magnitude
Micha Ruhl, assistant professor in Trinity’s School of Natural Sciences, led the team. He said:
“Scientists have long thought that the onset of molten volcanic rock, or magma, from deep inside the Earth as mantle plumes was the instigator of this volcanic activity, but new evidence shows that the normal speed 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 rate of continental plate motion slows to near zero can magmas from mantle plumes effectively reach the surface, triggering large igneous province volcanic eruptions and their associated climate disturbances and extinctions massive
“Crucially, further assessment shows that reduced continental plate motion likely controlled the initiation and duration of many of the major volcanic events throughout Earth’s history, making it a fundamental process for control the evolution of climate and life on Earth’s surface throughout Earth’s history. this planet.”
Studying past global change events, such as the Toarcian, allows scientists to unravel the different processes that control the causes and consequences of global change in the carbon cycle and to constrain the fundamental Earth system processes that control tipping points. turning point in the Earth’s climate system.
The research was carried out as part of the JET (Early Jurassic Earth System and Timescale) project of the International Continental Drilling Program (ICDP) and with the financial support of the SFI Center for Research in Applied Geosciences (iCRAG), the Natural Environment Research Council UK (NERC), the National Science Foundation China and the EU’s Horizon 2020 programme.
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Materials provided by Trinity College Dublin. Note: Content can be edited for style and length.