TOHOKU UNIVERSITY
Researchers in Japan, Sweden and the US have unearthed evidence that low volcanic temperatures led to a fourth mass extinction, allowing dinosaurs to flourish during the epoch. Jura.
Large volcanic eruptions create climate fluctuations, ushering in evolutionary changes. However, it is the temperature of the volcano when it erupts that determines whether the climate cools or warms.
Since the appearance of primitive animals, five mass extinctions have occurred. The fourth mass extinction occurred at the end of the Triassic – about 201 million years ago. This mass extinction saw many marine and land animals go extinct, especially the large-bodied, crocodile-like reptile known as pseudosuchia. About 60-70% of the animals have disappeared. As a result, small-bodied dinosaurs were able to grow and prosper.
Scientists think the fourth mass extinction was triggered by eruptions in the Mid-Atlantic Magmatic Province – one of the largest volcanic rock regions. But the correlation between the eruption and the mass extinction remains unclear.
Using analysis of sedimentary organic molecules and a heating experiment, current professor emeritus at Tohoku University, Kunio Kaiho and his team demonstrated how low-temperature magma slowly heats sedimentary rock. accumulation, causing high sulfur dioxide (SO2) and low carbon dioxide (CO2) emissions.
SO2 gas is distributed throughout the stratosphere, converted into sulfuric acid aerosols. The instantaneous increase in global albedo caused a short-lived cooling down, which may have contributed to the mass extinction.
Kaiho and his team took samples of marine sedimentary rocks from Austria and the UK and analyzed the organic molecules and mercury (Hg) in them. They found four discrete benzos[e]pyrene + benzo[ghi]perylene + coronene -Hg enriched.
The discovery of low coronene in the first enrichment was exceptionally revealed. The second, third and fifth mass extinctions had high concentrations of coronene. Low concentrations indicate that low-temperature heating causes high SO2 emissions and global cooling.
“We believe that the extinction was the product of large volcanic eruptions because of benzo[e]pyrene + benzo[ghi]Kaiho said.
Kaiho’s team is currently studying other mass extinctions in the hope of understanding more about the causes and processes behind them.
JOURNEYS
Earth and Planetary Science Letters
ARTICLE TITLE
Volcanic temperature changes modulated volatile release and climate variability during the late Triassic mass extinction.
ARTICLE PUBLICATION DATE
January 12, 2022
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