The mass extinction of life on land 250 million years ago was caused by…

About 250 million years ago, the largest extinction event occurred on Earth, with more than 70% of land life and 90% of marine life disappearing. The latest research by Professor Shen Yan'an's research team at the University of Science and Technology of China believes that the Siberian "super volcano" at that time spewed a huge amount of sulfur dioxide into the atmosphere, causing the Earth's surface to suffer from sulfuric acid rain corrosion and other disasters, which may be the main cause of the mass extinction of terrestrial life.

There have been five mass extinction events in Earth's history, and the third one at the end of the Permian period about 250 million years ago was the most tragic. Trilobites, sticklebacks, ancient corals and other animals in the ocean became extinct, most animals and insects on land became extinct, and the mass extinction of plants caused the loss of coal seams during this period. The cause and mechanism of this mass extinction has always been a major topic of concern in the academic community.

Fossils of the liana fern, which became extinct at the end of the Permian period. (Photo provided by Shen Yan'an's research team)

Shen Yan'an's research team collaborated with foreign researchers to study the Permian to Triassic strata in the Sydney Basin of Australia. By measuring and analyzing more than 1,000 meters of underground borehole samples and related strata, the researchers determined the strata where terrestrial organisms became extinct in the Sydney Basin, thereby determining the time of their extinction.

Further high-precision testing of pyrite in related strata revealed that the sulfur isotope content of pyrite was basically the same before and after the extinction of terrestrial life, but it dropped significantly during the extinction period.

"Our research found that this anomaly in sulfur isotopes was related to a sharp increase in sulfate concentrations in the lake water of the Sydney Basin at that time." Dr. Li Menghan from Shen Yan'an's research team said that these sulfates came from atmospheric deposition and originated from the eruption of the Siberian "super volcano."

The extinction layer of the northern edge of the Sydney Basin in Australia (indicated by the red line). (Photo provided by Shen Yan'an's research team)

The Siberian "supervolcano" has been erupting for hundreds of thousands of years since the end of the Permian period, triggering a chain reaction in the earth's ecology. This study shows that the sulfur dioxide emitted by the volcano is converted into sulfate aerosols that spread around the world, forming "sulfuric acid rain" that corrodes the surface environment system. In addition, it also produces an "icehouse effect" that causes global cooling, leading to the mass extinction of terrestrial life.

The results were recently published in the international academic journal Earth and Planetary Science Letters.

Source: Xinhua News Agency