Explanation to the great volcanic events that unleashed extinctions


The slowing down of the movement of continental plates was the key event that allowed the magma to rise to the surface and provoke the largest volcanic events on the planet.

The study, published in the journal ‘Science Advances’thus sheds new light on the timing and likely cause of the major volcanic events that occurred millions of years ago and caused such climatic and biological upheaval that they fueled some of the most devastating extinction events in Earth’s history.

The history of the Earth has been marked by large volcanic events, called Large Igneous Provinces (GPI), the largest of which have caused significant increases in carbon emissions in the atmosphere that have warmed the Earth’s climate, they have 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 1.5 km deep well in Wales, an international team led by scientists from the School of Natural Sciences at Trinity College Dublin, Ireland, were able to link two key events from a few years ago. 183 million years ago (the Toarcian period).

The team found that this period, which was characterized by some of the most severe climatic and environmental changes in history, directly coincided with the onset of extensive volcanic activity and subsequent release of greenhouse gases in the southern hemisphere. in what is now known as southern AfricaAntarctica and Australia.

Investigating further, and more importantly, the team’s plate reconstruction models helped them uncover the key fundamental geological process that seemed to control the timing and initiation of this and other large volcanic events.

Micha Ruhl, associate professor in the School of Natural Sciences at Trinity and leader of the team, comments it’s a statement that “scientists have long thought that the start 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 movement of the continental plates, several centimeters a year, It effectively prevents magma from penetrating the Earth’s continental crust.”

As he states, “it seems that only when the speed of the movement of the continental plates is reduced to almost zero, the magmas of the mantle plumes can reach the surface, causing large volcanic eruptions in the igneous provinces and climatic disturbances and mass extinctions. involving”.

“Crucially, further evaluation shows that a reduction in continental plate motion probably controlled the start and duration of many of the major volcanic events throughout Earth’s history –he continues–, which makes it a fundamental process in controlling the evolution of climate and life on the Earth’s surface throughout the history of this planet”.

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

The research was carried out as part of the Early Jurassic Earth System and Timescale (JET) project of the International Continental Drilling Program (ICDP), with financial support from SFI’s Center for Research in Applied Geosciences (iCRAG), the Council Natural Environment Research Foundation (NERC), the National Science Foundation of China, and the EU’s Horizon 2020 programme.

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