What caused the Permian-Triassic extinction event?
Between 75 degrees and 50 degrees north latitude and 60 degrees and 120 degrees in Tokyo, that is, on the vast Siberian plain of Russia, there is a large area of dark basalt with a total area of 3 million square kilometers, which is already a weathered area. Geologists estimate that the initial area of dark basalt is as high as 7 million square kilometers, almost equivalent to the area of Australia!
This is the result of super volcanic eruption between Permian and Triassic. The volume of lava ejected is about 6.5438+0 million to 4 million cubic kilometers. This volcano is related to the mantle plume under the Siberian Craton. Mantle plume is a way of thermal convection in mantle magma layer. The hotter mantle magma layer will rise from the bottom of the mantle to the top of the mantle!
If a volcano happens to form at the top, it will continuously send the magma inside the earth to the ground under the action of mantle plume. Because it is directly connected with the mantle layer, this eruption time is almost endless. According to geologists' estimation, this Siberian shield volcano has erupted for about 654.38+0 billion years!
Astronomical carbon dioxide and the heat in the earth are discharged into the atmosphere, melting the permafrost on the Siberian tundra, resulting in a large amount of methane being discharged into the atmosphere, which has formed an extremely serious greenhouse effect. In just a few thousand years, about 75% of terrestrial life and 95% of marine life on the earth have become extinct! This was once the scientific identification of the causes of the Permian and Triassic mass extinctions, and it was also basically recognized by the scientific community.
Permian and Triassic creatures began to die out in the early stage of Siberian Shield volcano eruption.
A large number of Permian-Triassic fossils are preserved in dolomite in the southern Alps, including a large number of brachiopod marine fossils. By studying the boron in these fossils, the research teams of university of ferrara and Rome University reconstructed the marine environment 252 million years ago, especially the change of PH value!
They found that the main reason for the extinction of marine life is ocean acidification, and the chief culprit of acidification is that a large amount of carbon dioxide in the atmosphere is dissolved in the ocean, and the source of these carbon dioxide is Siberian shield volcano! So in the early days when a large amount of carbon dioxide was ejected, the deterioration of the marine environment led to the extinction of living things!
Brachiopod fossils
Since then, the serious greenhouse effect caused by a large amount of carbon dioxide has also led to the increase of the earth's temperature, the intensification of land weathering, and the erosion of a large number of nutrients into the ocean through precipitation, which has led to the over-fertility of the ocean, leading to the lack of oxygen and sulfide poisoning in marine organisms in Permian and Triassic.
What is the relationship between global warming and ocean acidification?
Maybe everyone is a little confused, in fact, this is the inevitable result of the earth's carbon cycle out of control! Carbon is one of the most important elements in life. Because protein, purine and pyrimidine are all hydrocarbon derivatives, life on earth is called carbon-based life!
Before the industrial revolution, the carbon cycle on the earth was carried out in a natural way. Plants solidify carbon dioxide in the atmosphere, convert it into glucose and then enter the food chain. Animals ingest plants and carbon enters animals. Animals will return carbon to nature through breathing and decay after death, while the remaining plants will rot or turn into coal, which will be stored in the largest carbon pool and fossil fuel pool on the earth.
Another cycle is in the ocean. Organic carbon and inorganic carbon are two ways, the former constitutes a biological organism, and the latter becomes the skeleton and shell of the organism. Finally, the creatures die, and the shells are deposited on the seabed and re-enter carbonate in the crust, such as calcium carbonate. The atmosphere and ocean will also exchange carbon dioxide through waves, but the interaction between them is roughly the same!
After the appearance of human beings, fossil fuels were mined, and calcium carbonate in the earth's crust was mined as building materials. Therefore, the balance of carbon cycle in nature has been broken, and carbon in the atmosphere is gradually increasing. The most obvious result of the increase of carbon dioxide is the greenhouse effect caused by it, which directly leads to the melting of polar glaciers and the increase of extreme weather around the world.
Another unobvious result is ocean acidification. Coral ecology, the most important part of marine ecology, is being destroyed year by year. The speed of extinction caused by human expansion is making paleontologists feel that the speed of extinction is even comparable to that of early extinction.
The research team in university of ferrara, Italy, warned the world that the Permian-Triassic extinction began with ocean acidification. At present, fossil fuels widely used by human beings are rapidly releasing carbon solidified in the earth's crust into the atmosphere at a speed of tens of thousands of times that released by nature, and human beings will play the role of initiator and ultimate victim in this process!
In a sense, human beings are slowly committing suicide!