Slowdown in continental plates linked to volcanic eruptions triggered mass extinctions: study

The slow-moving continental plates may have triggered a series of volcanic eruptions and mass extinctions in the Toarcian period – the hottest range of the Jurassic period – some 183 million years ago. This is what emerges from a new study published in Science advances.

The continental plates have been in motion for hundreds of millions of years. This allowed the continental masses to merge and divide over different periods.

The new study shows that a decline in continental plate movement likely controlled the onset and duration of many major volcanic events throughout Earth’s history, Micha Ruhl, assistant professor at Trinity’s School of Natural Sciences, said in a statement.

This makes it a “fundamental process in controlling the evolution of climate and life on the Earth’s surface throughout the history of this planet,” he added.

Previous studies have linked major volcanic eruptions with past mass extinctions and perturbations of the global climate, environmental and carbon cycle.

The volcanism of the great igneous province, the formations due to the great volcanic eruptions that occurred throughout the history of the Earth, have released large amounts of greenhouse gases and toxic compounds into the atmosphere, Ruhl said. Down to earth.

The sea has warmed by 4 ° C to 10 ° C, even at mid-low latitudes, the study notes. Rising acidity levels and a lack of oxygen have led to major ocean extinctions.

Around this time, Ruhl said, large-scale volcanism took place in southern Africa, Antarctica and Australia. This is known as the great igneous province of Karoo-Ferrar.

Researchers from the UK and Canada have collected sediments lying on the seabed of the Cardigan Bay washbasina large cove of the Irish Sea.

Sediments from the Toarcian period showed high levels of mercury, which are orders of magnitude higher than sediments formed in other times, Ruhl said. Modern volcanoes also release mercury into the ocean and atmosphere.

This indicates a direct link between volcanic activity and the associated greenhouse gas release, climate or environmental change at that time, Ruhl said.

Next, the researchers used models to reconstruct the position of the continents at different periods. After comparing these models with the age of volcanic activity, they observed that continents moved at less than two centimeters per year.

This pattern emerged not only in the great igneous province of Karoo-Ferrar, but also in the Siberian traps, linked to the Great Death 250 million years ago, the Rift Valley of East Africa and the igneous province of the North Atlantic.

This slowing of movement gives the mantle below more time to erode the continent’s base, eventually leading to volcanic activity.

This is similar to putting paper under a candle. When the paper is moved quickly over the candle, it may turn black but is unlikely to burn as a whole, Ruhl said. But if the paper moves slowly over the flame, there is enough time to burn it completely.

In the future, there is a possibility that continental plates could slow down, potentially triggering volcanic activity, Ruhl said.

“But at this stage, it may be difficult to predict in detail where and when this might happen,” he said, adding that more work needs to be done.