The slowdown of continental plates linked to volcanic eruptions triggered mass extinctions: Study

The slowdown of continental plates linked to volcanic eruptions triggered mass extinctions: Study

Subject: Geography

Context: 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, according to a new study published in Science Advances.

The theory behind the study-

• Continental plates have been on the move for hundreds of millions of years. This enabled landmasses to fuse and split during different periods.
• The new study shows that a decline in continental plate movement likely controlled the onset and duration of many of the major volcanic events throughout Earth’s history.
• This makes it a “fundamental process in controlling the evolution of climate and life at Earth’s surface throughout the history of this planet.”

How slow movement of continental plate leads to volcanic eruptions-

• This is similar to placing paper under a candle. When the paper is moved swiftly over the candle, it may turn black but is unlikely to burn as a whole.
• But if the paper moves slowly over the flame, there is enough time to burn the paper completely.
• In the future, there is a possibility that continental plates may slow down, potentially triggering volcanic activities.

Observations-

• Researchers from the United Kingdom and Canada collected sediments lying on the seafloor of the Cardigan Bay basin, a large inlet of the Irish Sea.
• The sediments from the Toarcian Period showed elevated levels of mercury, which is orders of magnitude higher than sediments that formed in other times.
• Modern-day volcanoes also release mercury into the ocean and atmosphere.
• This indicates a direct link between volcanic activity and the associated greenhouse gas release, climatic or environmental change at that time.

Previous studies-

• Earlier studies have linked major volcanic eruptions with past mass extinctions and disturbances in the global climatic, environmental and carbon cycle.
• Large igneous province volcanism, formations due to major volcanic eruptions occurring throughout Earth’s history, released large quantities of greenhouse gasses and toxic compounds into the atmosphere.
• The sea warmed up by 4°C to 10°C, even at low- to mid-latitudes. Increased acidic levels and a lack of oxygen drove major ocean extinctions.
• Around this time, large-scale volcanism took place in southern Africa, Antarctica and Australia.
• This is known as the Karoo-Ferrar Large Igneous Province.

Modelling of the theory-

• The researchers used models to reconstruct the location of continents in different periods.
• After comparing these models with the age of volcanic activity, they observed that the continents moved at less than two centimetres per year.
• This pattern emerged not only Karoo-Ferrar Large Igneous Province but also in the Siberian traps — linked to the Great Dying 250 million years ago, the East African Rift valley and the North Atlantic Igneous Province.
• This slowdown in movement gives the underlying mantle more time to erode the continent’s base, ultimately leading to volcanic activity.

Conclusion-

• In the future, there is a possibility that continental plates may slow down, potentially triggering volcanic activities, according to researchers.
• But at this stage, it may be challenging to predict in detail where and when that may happen.