The link between an ancient volcanic eruption and the most severe extinction event the world has ever seen is even stronger. Mercury The isotope provides evidence that 2.5 billion years ago, a remote part of Earth’s southern hemisphere was covered in debris from a Siberian volcanic eruption.
So-called great death, also called Permian-Triassic mass extinction eventafter which most life was wiped out under an ash-covered sky.
With more than 90% of marine life lost and more than 70% of terrestrial vertebrates gone, it’s clear how things ended, but despite the best efforts of geologists, the world’s largest Our understanding of how the extinction event unfolded remains a bit cloudy.
By piecing together traces of chemicals trapped in rocks and marine sediments, geoscientists are fairly certain that a series of volcanic eruptions caused a series of dramatic changes to Earth’s atmosphere and oceans. increase. finally suffocated the animal.
But an equally big extinction event great dying It also takes a fairly solid case for geoscientists to articulate what caused it and when it happened. After all, they squint about 252 million years ago.
In previous studies, zinc and nickel It has been used to link changes in ocean chemistry to large-scale volcanic activity and loss of marine life. However, these elements, unlike isotopes, are recycled on the Earth’s surface. Mercury Provides a much more stable signal of volcanic activity.
Also, many studies of this mass extinction event have focused on sites in the Northern Hemisphere, making it difficult to understand the impact of volcanic activity on the Earth’s underside. This is important because there is growing evidence that it was multiple extinction episodes that occurred in waves over 100,000 years ago.
So paleoclimatologist Jun Shen and colleagues at the China University of Geosciences set out to detect it. Mercury Isotopes in rock sediments from two locations in the Southern Hemisphere: the Karoo Basin in south-central Africa and the Sydney Basin on the east coast of Australia.
At the time of the Great Extinction, the basin was merged into a single supercontinent. Pangeabut are now separated by about 10,000 kilometers (6,200 miles) and the Indian Ocean. Mercury Isotopes peaked towards the end of the Permian.
This evidence suggests that it is a massive lava flow formed by a volcano at the Epoch End in question, the farthest terrestrial location to date from the Siberian Traps. Mercury It was blown out of a northern hemisphere volcano and swept the globe, researchers say.
“Volcano emissions Mercury has a very specific isotopic composition Mercury Accumulated on the extinction horizon. ” I will explain Tracy Frank, study author and geologist at the University of Connecticut.
“By knowing the age of these deposits, we can more clearly link the timing of the extinction to a major eruption in Siberia.”
their job is Signal from sulfur isotope Consistent with the great death and also built upon Past research This suggests that the terrestrial mass extinction began 600,000 years ago, when marine life took its last few breaths.
“It suggests that the event itself wasn’t just an instant big blow.” I will explain Christopher Fielding, another geologist at the University of Connecticut.
“Not only did we have a very bad day on Earth, it took a long time to build, so to speak. It is reflected.”
Researchers admit that pinpointing the direct cause of mass extinctions is not easy.plume of ash from Volcanic eruption in southern China In addition to the Siberian Trap, it is also involved in the genocide.
So try to reconstruct the chain of events leading up to Earth’s greatest extinction event. Perhaps the more salient message to absorb is the fragility of life on a violent planet that is under pressure from much of the same climate change today. It’s a rise in temperature. and greenhouse gases.
This research Nature Communications.