Catastrophe Of Volcanic Eruption

Numerous volcanic eruptions led to the mass extinction of living organisms on Earth 252 million years ago, scientists found out. They were able to come to this discovery by examining traces of mercury in bottom sediments around the world. Volcanic eruptions have led to one of the largest biosphere catastrophes in the history of the Earth - the mass Permian extinction of living organisms, scientists of the University of Cincinnati and China University of Geosciences have established.
As follows from a joint study of paleontologists, published in the journal Nature Communications, evidence of this concept is traces of mercury, found in sediments of about 252 million years old and trapped in the atmosphere as a result of the burning of coal reserves. After that, mercury along with rainwater fell into the World Ocean, and then into marine sediments around the world, with which the authors of the article worked.
Volcanic activity, including gases and organic combustion, has released a lot of mercury to the surface of the Earth,” said Jun Shen, associate professor at China University of Geoscience. “As a rule, during large explosive eruptions, a lot of mercury is released into the atmosphere,” added his colleague Thomas Algeo of the University of California. - The eruptions were not necessarily intense, but very long. And the longer nature did not calm down, the greater the impact it had on the environment. ”
The epicentre of the eruptions was located on the territory of the Siberian traps (a type of volcanic activity, when huge volumes of liquid lava in a relatively short time, by geological marks, fill huge territories). As a result of the catastrophe, much of the flora and fauna that prevailed on Earth before the advent of dinosaurs was destroyed. Some of the animals inhabiting the planet at that time looked like a cross between a saber-toothed tiger and the Komodo dragon.
As a result of eruptions lasting hundreds of thousands of years, about 96 per cent of marine species, 73 per cent of terrestrial vertebrates and 83 per cent of insects disappeared. During the period of seismic activity, about three million cubic kilometres of ash were emitted into the Earth’s atmosphere, which caused the average temperature of the planet to increase by 10 degrees, and the acidity of the seas also increased. For comparison, the eruption of the volcano St. Helens in the United States in 1980 led to the release into the atmosphere of only 1 km³ of ash.
Many eruptions did not occur in conical volcanoes, but through cracks in the ground, scientists believe. According to Algeo, global warming has become one of the main causes of mass extinction. “We often have to wrestle with what is the most harmful. Creatures accustomed to a colder environment, then very unlucky. So I think the temperature change is killer number one. The consequences were aggravated by acidification of the seas and other toxins. ” Previously, researchers among the probable causes of mass Permian extinction called the collision with an asteroid, a large emission of methane from the sea floor and climate change. Volcanic activity was considered as one of the versions. Over 4.5 billion years on Earth, there have been five known mass extinctions.
In February of this year, an international group of scientists published the results of their study, according to which dinosaurs could also die due to numerous volcanic eruptions. If we proceed from the considerations of experts, a series of eruptions occurred about 66 million years ago. In addition, as scientists say, a giant meteorite collided with Earth. These factors were enough to destroy all the dinosaurs living on the planet. At the same time, Swedish geologists found traces of one of the most powerful ancient flares on the Sun in the ice of Greenland. They hope that further similar findings will predict strong outbreaks and prevent their consequences for civilisation.
--Pravda.ru  

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