Slow Continental Plate Movements Could Trigger Major Volcanic Events, Study Shows

A recent study has clarified the influence of slow continental plate movements on triggering major volcanic events.

The timing and likely origin of significant volcanic events that took place millions of years ago which caused such biological and climatic disruption have been clarified by scientists in their study. This included driving some of the most catastrophic extinction events in Earth's history.

Surprisingly, the new research suggests that the crucial event that allowed magma to rise and reach the surface of the Earth and cause the catastrophic knock-on effects was a slowing of continental plate movement.

Large igneous provinces (LIPs), or significant volcanic eruptions, have occurred throughout Earth's history. The largest LIPs have significantly increased atmospheric carbon emissions, warmed Earth's climate, caused unprecedented changes to various ecosystems, and led to mass extinctions both on land and in the oceans.

Ancient Mudstone Data

An international group of researchers led by scientists from the School of Natural Sciences in Trinity College Dublin was able to link two significant events that occurred around 183 million years ago using chemical data contained in ancient mudstone deposits acquired from a 1.5 km-deep borehole in Wales (the Toarcian period).

The team found that the incidence of major volcanic activity as well as associated greenhouse gas emissions in the southern hemisphere, in what is now known as Antarctica, southern Africa, and Australia, directly coincided with this period, which was marked by some of the most extreme climatic and environmental changes ever.

Further research-and more importantly-helped the team identify the crucial fundamental geological process that appeared to regulate the timing and beginnings of this volcanic event and many others of significant size.

Micha Ruhl, an assistant professor from Trinity's School of Natural Sciences, is the leader of the research team. He said that long believed by scientists to be the cause of such volcanic activity, the upwelling of magma, or molten volcanic rock, from deep within the Earth's interior as mantle plumes is prevented from penetrating the continental crust by the normal rate of continental plate movement, which is several centimeters per year.

He added that it appears that magma from mantle plumes can only effectively reach the surface when the rate of continental plate movement grinds to a halt to almost zero, leading to major large igneous province volcanic eruptions and their associated climatic disturbances and mass extinctions.

Analyzing History

Ruhl also said that, importantly, additional analysis demonstrates that a decrease in continental plate movement likely regulated the onset and duration of many major volcanic events all through Earth's history, making it a key process in regulating the evolution of climate as well as life at the planet's surface throughout its history.

The team of scientists can distinguish between the various processes that regulate the causes and effects of global carbon cycle change, and if not, constrain basic Earth system processes that regulate tipping points in the Earth's climate system by reviewing previous global change events, such as those in the Toarcian, Phys Org reports.