Scientists at the Center for Petrographic and Geochemical Research in France have found out how volcanic activity in Siberia about 252 million years ago became so strong that it led to the massive Permian extinction. It turned out that living organisms died out en masse due to the release of greenhouse gases stored in the Earth's lithosphere. This is reported by Science Alert.
The Permian Massive Extinction, or Great Extinction, is the largest ecological disaster in Earth's history. It is believed that it occurred due to the outpouring of huge volumes of magma throughout the East Siberian platform. As a result, 96 percent of marine species, 73 percent of terrestrial vertebrates, and 83 percent of insect species have disappeared. According to scientists, the depletion of biological diversity lasted 60 thousand years.
Volcanic activity, which was accompanied by emissions of ash and gases, led to the depletion of the ozone layer and warming up of the Earth's atmosphere. However, according to the calculations of scientists, the volumes of volatiles released during the outpouring of magma were not enough for a sharp climate change.
Researchers have studied Siberian peridotites - rocks that are contained in the upper part of the Earth's mantle and are thrown to the surface with volcanic eruptions. Peridotites occur in the form of xenoliths - rock fragments trapped in magma. The age of the analyzed samples reached 160-360 million years.
It turned out that the most ancient rocks contained a large number of halogens, including chlorine, bromine and iodine. These elements are found in seawater and enter the mantle when the oceanic crust submerges under the continental crust in subduction zones. At the same time, in younger rocks, the amount of halogens drops sharply. This indicated that huge volumes of volatile compounds (about 70 percent of their total) were released in a major catastrophic event that occurred about 250 million years ago. Thus, halogen-containing substances were released into the atmosphere and affected the global climate system.
