Split the supercontinent called glaciation of the Earth

26.03.2004

26.03.2004


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The cause of global glaciation of the Earth could be a collapse of the supercontinent, which occurred 750 million years ago. This decay, according to paleoclimatology could cause an increase in rainfall and increase erosion of rock. This, in turn, could cause the removal of greenhouse gases from the atmosphere and gaining more speed cooling. Such a mechanism can explain how a planet hit the fetters of ice, which, according to many scientists, occurred in the distant past.

The theory that the Earth was once completely frozen, has appeared in the 1960s, when researchers realized that if the polar ice sheets grow larger than a certain size, it may cause global cooling. Because ice reflects sunlight and heat back into space, the expanding ice sheets should cause a further cooling. Feedback of this kind had to make a very cold climate system. Presumably the planet could thaw out after the carbon dioxide from volcanoes, to break through the ice, again caused heating of the atmosphere.

• split the Rodinia caused a total icing

In the late 1980s, Joe Kirschvink of the California Institute of Technology, called the state of "frozen earth." Around the same time, experts began to look for geological evidence that such processes of freezing and thawing occurred in the history of the Earth at least once — at the end of the Proterozoic, about 600 million years ago. However, it was not clear what was the main reason for such a transition state. Now, Yannick Donnade from the Laboratory of Climatology and Environment in Gif-sur-Yvette, and his colleagues have found the explanation.

Donnade and his colleagues conducted computer simulations of global climate change that occurred 750 million years ago during the breakup of the supercontinent Rodinia. While the vast mass of the earth is crushed into smaller pieces under the influence of continental plates drift, evaporation of the smaller seas between isolated continents increased the amount of precipitation falling on the land. Increased rainfall accelerated weathering any naked rock in which a chemical reaction occurs that linked carbon dioxide from the air into carbonates. The more it rains, the more greenhouse gas was withdrawn from the air.

Scientists have also shown that the collapse of a part of Rodinia partially eruption of large masses of volcanic rock. Fresh volcanic rock was more reactive than the old one, and therefore quickly disappears and absorbed more carbon dioxide. In modeling the cumulative effect of increasing rainfall and accelerating erosion has reduced carbon dioxide levels below the threshold for the start of Education frozen earth.

25.03.2004

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