Experts find in the world mercury signatures that say rashes are responsible for "big murder"

Mercury dating back 252 million years was discovered in rocks and reinforces the growing belief that "great dieback" was caused by volcanoes.

The researchers found in the rocks powerful mercury signals dating back to this period, where 95% of life had been eliminated.

The signals were found in 10 different sites around the world and have been dated by studying the teeth of fossilized creatures resembling eels.

The causes of what is called "the great death" have been the subject of much discussion, but this study provides compelling evidence that volcanic eruptions were to blame.

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The massive extinction occurred 252 million years ago, nicknamed familiarly "the great dying," killed 95% of life on earth, which is catastrophic.

The geologic record marks the event as the boundary between the Permian and Triassic periods of time.

Rather than coming from vents located in stereotypically cone-shaped volcanoes, eruptions have occurred from huge cracks in the Earth's crust.

"Generally, when you have large and explosive volcanic eruptions, a large amount of mercury is released into the atmosphere," says paper author and geologist Thomas Algeo of the University of Cincinnati.

In addition, it is thought that the eruptions caused large coal deposits to ignite, releasing mercury vapor from the atmosphere.

In the end, this mercury has returned to the earth, leaving behind an environmental signature in marine sediments around the world.

It's this signature that researchers have detected on 10 sites around the world.

The study sites were chosen to represent various marine environments, including shallow and deep environments, both near and far from the site of the eruption.

The disaster has ravaged the live amphibian and reptile species of the time and would have created an environmental space that would allow new groups – including dinosaurs – to evolve.

Terrestrial and marine species have been affected by the disaster.

It has long been argued that mass extinction was triggered as a result of massive volcanic activity in Siberian traps.

The traps are located in what is now central Russia.

In total, it is thought that Siberian traps pumped up to 3 million cubic kilometers of ash into the atmosphere during volcanic activity.

By way of comparison, the violent eruption of Mount St. Helens in Washington, United States, in 1980, sent only 0.2 thousand cubic feet of ash into the atmosphere.

It is good that the ashes of the mountain were recorded as falling as far as Oklahoma, at a distance of 3,218 kilometers.

"Mercury is a relatively new indicator for researchers. It has become a hot topic for investigating volcanic influences on major events in the history of the Earth, "said Professor Algeo.

Professor Algeo collaborated with colleagues from Cincinnati and the China University of Geosciences,

Researchers used the sharp, fossilized teeth of creatures called conodonts – which look like eels – to date the rocks in which they found deposited mercury.

Like the majority of creatures living on the planet 252 million years ago, conodont extinctions have been hard hit by Permian-Triassic extinction.

However, they have survived for about 52 million years.

According to Professor Algeo, the volume of material released by the traps, in particular greenhouse gases, would have warmed the planet by 10 ° C on average.

This climate change would have been a major force in mass extinction.

"We often have to ask ourselves what was the most harmful," said Professor Algeo.

"Creatures suited to colder environments would not have been lucky. So, I guess the change in temperature would be the # 1 killer, "he added.

At the same time, acid rain would have spoiled masses of water while increasing the acidity of the world's oceans.

The warmer water would not have been able to contain as much dissolved oxygen, creating inhospitable dead zones.

The mere duration of volcanic eruptions of traps would have made life even more difficult to cope with environmental changes.

"It's not necessarily the intensity but the duration that counts. The longer it lasted, the greater the pressure on the environment, "said Professor Algeo.

Researchers are now trying to determine the extent of Siberian trap eruptions, alongside the most devastating environmental effects.

The knowledge gained here could be vital today.

"The carbon emissions into the atmosphere by humans are similar to those of the upper Permian, where Siberian eruptions released carbon in abundance," said paper author Jun Shen, a researcher at the China University of Geosciences, Wuhan.

Professor Algeo agrees that this is worrying.

"A majority of biologists think we are at the dawn of another mass extinction – the sixth great," he added.

"What we should learn is that it will be a serious matter that will hurt human interests, so we must strive to minimize the damage."

People living in marginal environments such as arid deserts will suffer first. This will lead to more climate refugees around the world.

"We are likely to see more hunger and massive migration in the hardest-hit areas," adds Professor Algeo.

"This is a global problem that we should recognize and deal with proactively. It is much easier to solve these problems before they reach a crisis. & # 39;

Permian-Triassic extinction is not the only disaster of this type that researchers have studied with the help of elemental signatures.

The mass extinction that killed the dinosaurs 65 million years ago is associated with an overall signature of concentrated iridium – an element that is rare on Earth.

Scientists believe that iridium comes rather from a huge meteor striking the planet off the Gulf of Mexico.

Iridium dust would have been blown across the world, forming a thin layer that can be found today in the rocks.

The complete results of the study were published in the journal Nature Communications.