About 200 million years ago, there were one of the Big Five mass extinctions due to giant volcanic eruptions and an asteroid impact. It led to such climate change that it killed off almost half of the Earth's species.
The Earth's mass extinction happened in the late Triassic period, with huge quantities of carbon dioxide spewed into the air at the time. There were almost 1000 ppm or so concentrations of the gas into the atmosphere at the time. Today, the atmospheric concentration is 410 ppm of CO2. This is quite a serious situation for scientists.
Apart from the warming effects of the carbon-dioxide concentrations in the atmosphere, it was important that there was a dissociation of huge amounts of methane hydrates. They heightened and intensified the warming effect during the mass extinction, according to Jochen Knies of CAGE and Geological Survey of Norway. He is a co-author on recent Nature Communication study. The research discovered the effect of hothouse climate conditions on the Triassic period in Scandinavia.
Ola Fredin from Geological Survey of Norway as well as her team published an article on how greenhouse gas concentrations and chemical weathering led to the disintegration of the bedrock as well as the mass extinction. When water reacts with mineral grains in rocks, it leads to the formation of new minerals such as clay mineral illite. The reactions take place in acidic water when the carbon dioxide levels shoot up.
"We have managed to precisely date deeply weathered crystalline bedrock from the North Sea and across Scandinavia, which then was part of the supercontinent Pangea. We did this by detailed geomorphological and mineralogical analyses of weathered rocks combined with the dating of clay mineral illite", says Knies, according to an article on the mass extinctions in Science Daily.
In the later Triassic Big period, the intensive and widespread chemical weathering took place due to hothouse conditions. There was a slow transformation of the bedrock, along with emerging volcanic activity. The mass extinction created such hothouse conditions that the oceans became depleted of oxygen, becoming unlivable. However, the silicate got weathered in the bedrock of Pangea, leading to the formation of carbonate. Hence, the carbon dioxide got tied up into the minerals and removed it from the environment.
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