Chinese scientists propose new mechanism for mass extinction of life on Earth 440 million years ago

Forty-four million years ago, the Earth was subjected to a major extinction event, which led to the disappearance of about 85 percent of animal species, and the international community has debated the cause of extinction for more than 30 years. Recently, Shen Yan’an of the University of Science and Technology of China used a new method to study that the volcanic eruption caused by the climate upheaval is the real cause of the mass extinction, this study is also instructive for the analysis of modern global climate change. The results were published in Nature Newsletter, an international authoritative academic journal.

Chinese scientists propose new mechanism for mass extinction of life on Earth 440 million years ago

Since the outbreak of Cambrian life more than 500 million years ago, there have been five mass extinctions on Earth, the first of which occurred at the end of the Otou Period 440 million years ago. At that time, all animals lived in the ocean, and invertebrates such as Nautilus, penstone and coral satiaris flourished like never before, but the mass extinction killed about 85 percent of the species. Traditional studies have suggested that the Earth entered the glacial period, and the ocean’s lack of oxygen caused by rising temperatures at the end of the glacial period, which led to the mass extinction caused by the “two-act” climate upheaval.

However, there is growing evidence that the “two-act” extinction of life at the end of the Otao period is not exactly in line with the time of formation and melting of glaciers, which is debated by the international academic community.

Recently, Shen Yan’an team opened up new ideas, they found in southern China with the same era of the great extinction of the yellow iron ore, the sulfur isotopes in the high-precision analysis, proposed is the volcanic eruption triggered and drove the event of the great extinction of life.

Chinese scientists propose new mechanism for mass extinction of life on Earth 440 million years ago

They found that volcanic eruptions at the end of the Otao period sent large amounts of sulfur dioxide, hydrogen sulfide, etc. to an altitude of 20 kilometers, reaching the atmospheric stratosphere and forming a sulfate-based “aerosol layer” there.

“Simply put, the aerosol layer ‘intercepts’ the sun’s heat and makes the earth cold. But over time, the sulfates in the aerosol layer will ‘drop’ to the ground, and the greenhouse gases released by the volcano will take up the upper hand, which in turn will cause the planet to warm dramatically. Shen Yan’an said it was this “cold, one hot and cold” that alternated over and over led to the mass extinction of life. The different chemical reactions produced by “one cold, one heat” will settle to the surface with acid rain and other things, and be stored in rocks, becoming the “key” to the puzzle series hundreds of millions of years later.

Satellite observations show that the concentration of sulfates in the stratosphere of the Earth’s atmosphere has been increasing in the past 50 years. Some believe it is caused by human emissions, while others believe that it is caused by modern volcanic eruptions. Shen Yan’an believes that high-precision sulfur isotope analysis can provide a means to seek causes and countermeasures.