Slowing continental plates associated with volcanic eruptions triggered mass extinctions: study

Slow-moving continental plates may have triggered a series of volcanic eruptions and mass extinctions in the Toarcian period — the warmest interval of the Jurassic period — about 183 million years ago. That’s according to a new study published in scientific advances.

Continental plates have been moving for hundreds of millions of years. This allowed land masses to merge and split at different times.

The new study shows that a retreat in tectonic plate motion likely controlled the onset and duration of many of the most important volcanic events in Earth’s history, Micha Ruhl, an assistant professor at Trinity School of Natural Sciences, said in a statement.

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

Previous studies have linked large volcanic eruptions to past mass extinctions and disruptions to global climate, the environment, and the carbon cycle.

Large provincial volcanism, formations due to large volcanic eruptions that have occurred throughout Earth’s history, have released large amounts of greenhouse gases and toxic compounds into the atmosphere, Ruhl said Stayed on the ground.

The sea even warmed by 4°C to 10°C at low to mid-latitudes, the study found. Increased acidity and lack of oxygen led to large-scale ocean extinctions.

Around this time, Ruhl said, large-scale volcanism was taking place in southern Africa, Antarctica, and Australia. This is known as the Karoo-Ferrar Large Igneous Province.

Researchers from the UK and Canada collected sediment lying on the ocean floor Cardigan Bay basina large bay of the Irish Sea.

The sediments from the Toarcian period showed elevated levels of mercury that are orders of magnitude higher than sediments formed at other times, Ruhl said. Modern volcanoes also release mercury into the ocean and atmosphere.

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

Next, the researchers used models to reconstruct the location of the continents in different periods. After comparing these models to the age of volcanic activity, they found that the continents were moving at less than two centimeters per year.

This pattern appeared not only in the great Karoo-Ferrar magmatic province, but also in the Siberian traps associated with the great extinction 250 million years ago, in the East African Rift Valley, and in the North Atlantic magmatic province.

This slowing of movement gives the underlying mantle more time to erode the base of the continent, ultimately leading to volcanic activity.

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

In the future, there’s a chance the continental plates will slow, possibly triggering volcanic activity, Ruhl said.

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