New evidence of volcanic activity, which caused the most massive extinction in history, is received.
Volcanic eruption in the pouring rain
Source: Illustration / Margaret Weiner / UC Creative Services
Researchers claim that mercury hidden in ancient rocks is convincing evidence that volcanoes caused the most massive extinction of living things in history.
The extinction of living beings, which took place 252 million years ago, was so vast and dramatic that scientists called it the Great. Disaster destroyed more than 95 percent of life on earth for hundreds of thousands of years ( estimates of the length of the extinction period vary from one publication to another - approx. Transl. ).
Paleontologists, together with the University of Cincinnati (the University of Cincinnati , USA) and the China University of Geosciences (English - China University of Geosciences), claim that they recorded a sharp increase in the amount of mercury in the geological profile of a dozen places around the globe. In their opinion, this is convincing evidence that volcanic eruptions led to a global catastrophe.
The study was published this month in the journal Nature Communications.
Volcanic eruptions ignited vast coal deposits, releasing mercury vapor into the atmosphere. In the end, it fell in the rain and settled in sediments all over the planet, witnessing the catastrophe that became the forerunner of the dinosaur era.
“Volcanic activity, including the release of volcanic gases and the burning of organic material, released excess mercury, which then deposited on the surface of the Earth,” said lead author, Jun Shen, an assistant professor at China University of Geosciences.
Mass extinction took place on the border between the Permian and Triassic geological periods. It led to the destruction of most representatives of land and marine flora and fauna before the onset of the era of dinosaurs. Some of the extinct species were prehistoric monsters, such as the formidable gorgonopsids, which looked like a cross between a saber-toothed tiger and a monitor lizard.
Reconstruction of the appearance of gorgonopsid. Author: NutkaseCreates
Eruptions arose in a volcanic system called the Siberian Traps, located in the Siberian part of modern Russia. Many of the eruptions did not come from cone-shaped volcanoes, but from faults on the surface of the earth. Eruptions were frequent and long; their total duration dragged on for a period of hundreds of thousands of years.
“Typically, when a volcano erupts violently, large amounts of mercury enter the atmosphere,” says Thomas Algeo, professor of geology at the College of Humanities and Natural Sciences at the University of Cincinnati.
“Mercury is a relatively new indicator for researchers. She gained relevance in studying the degree of impact of volcanoes on major events in the history of the planet, ”he added.
To determine the age of the breed in which the mercury was discovered, researchers use the fossilized teeth of conodont , a creature resembling a modern lamprey. Like many other species of living things, conodonts were destroyed by the disaster.
Over the entire period of eruptions, about three million cubic kilometers of ash were thrown into the air. For comparison, during the eruption of St. Helens in Washington State, 1 cubic kilometer was thrown into the air. Then the ashes fell on the windshields of cars in Oklahoma ( this is at a distance of more than 2 thousand km. - approx. Transl. )
“In essence,” says Thomas Algeo, “Siberian traps threw so much material, especially greenhouse gases, into the air that it raised the planet’s temperature by an average of 10 degrees Celsius.”
“Warming most likely became one of the main culprits of the mass extinction,” he says. “Poisonous rains poisoned a large number of water sources and increased the acidity of the ocean. Due to the lack of dissolved oxygen in the warmed water, lifeless zones appeared. ”
“We often reflect on what has become fatal. Creatures accustomed to colder conditions had no chance, ”says Thomas Algeo.“ In my opinion, the temperature jump is the No. 1 culprit. The conditions were exacerbated by the release of toxic substances into the environment. ”
The eruptions that lasted for a long period of time after the eruptions did not allow the food chain on our planet to recover.
“What matters is not the intensity, but the length of the process described,” says Thomas Algeo, “the longer it lasted, the greater the impact on the environment.”
“Thus, the planet was recovering very slowly from the effects of the disaster, due to the fact that the shocks continued to destroy its biological diversity.”
For 4.5 billion years, the Earth has witnessed five mass extinctions.
Scientists use another elemental indicator - iridium - in order to determine the cause of global extinction, which about 65 million years ago wiped dinosaurs off the face of the earth. They believe that a huge meteorite crashed into the territory of modern Mexico.
As a result, hot earth masses were thrown into the atmosphere and settled in the form of a substance containing iridium, which was found in a geological profile around the globe.
Jun Shen claims the mercury footprint is strong evidence that Siberian trap eruptions are the culprits of the disaster. Currently, researchers are trying to determine the magnitude of the eruptions and which of their consequences is the main cause of mass death, in particular, of animals and plants on earth.
Shen believes Permian extinction could shed light on today's global warming, which could lead to the next global extinction. If global warming is actually responsible for the extinction of species in the Permian period, then what is today's warming for living on Earth?
“Human emissions of combustion products into the atmosphere are similar to the situation that occurred at the end of the Perm period, when excess carbon was released into the atmosphere,” says Jun Shen.
Thomas Algeo also calls this a cause for concern.
“Most biologists believe that we are on the verge of yet another major global extinction - the 6th. I share this view, ”says Algeo. “We must understand that this is a serious process that will harm the whole of humanity, and work to minimize damage.”
People living in extreme conditions, such as waterless deserts, will be the first to suffer, leading to a large number of climate refugees around the globe.
“Most likely, we will see even more hunger and mass migration in places where the blow will be the hardest. This is a global issue and we should take proactive steps. It’s easier to deal with a problem before it develops into a crisis. ”
Link to research materials:
Jun Shen, Jiubin Chen, Thomas J. Algeo, Shengliu Yuan, Qinglai Feng, Jianxin Yu, Lian Zhou, Brennan O'Connell, Noah J. Planavsky. Evidence for a prolonged Permian – Triassic extinction interval from global marine mercury records. Nature Communications, 2019; 10 (1) DOI: 10.1038 / s41467-019-09620-0