Varanger glaciation
The glaciation Varanger is one long period of Glaciation of the Ground, at the time of the Cryogénien.
A theory supports that it quasi totality of the surface of the Earth was covered with ice during this glaciation; this theory is known under the name of snowball Earth , i.e. Ground snowball .
750 million years ago, at the end of the Protérozoïque:
The glaciation of the Earth would have been caused by an important reduction in the Carbonic gas in the atmosphere due to the dislocation of the Supercontinent Rodinia which, at the time, was centered on the equator and extended from the 60e northern degree of Latitude to the 60e degree of southern latitude.
Rodinia started to be fractured 800 million years ago under the effect of hot spots, kinds of lances magma ticks which cross the Earth's crust and spit of enormous quantities of lava. This event was accompanied by the opening by Océan S and arms of the sea which increased the quantity of steam present in the atmosphere, and thus the rains. The Carbone present in the rains in the form of carbonic gas was found soon in the ocean, trapped in the Sédiment S in the form of Carbonate S.
In same time, the enormous flows of lava produced by the fracture of Rodinia formed basaltic surfaces on the surface of the continents. However these last consume eight times more carbon than the same granitic surface when they erode under the effect of moisture.
In addition, the Sun was younger and diffused 6% of heat in less.
In spite of the Ice which went down to the equator, the volcanic activity continued to emit of CO2 and the Méthane (CH4) in the atmosphere.
When the concentration of this gas reached 350 times that of today, there would have been a sufficient Greenhouse effect to start the rout.
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