What is the cryogenic period?
The cryogenic period is a geological period from 850 million to 630 million years. It happened before the era Ediacaran and after the Tonian period and is part of a much longer Proterozoic era, which means the "era of primitive life". In Greek means cryogenic "the origin of the ice". Although Ice really does not come from the cryogenic period, it was everywhere and the glaciers could spread from pole to pole. Until then, a person transported by then could be able to ski across the country. The cryogenic period is one of the few geological periods over the last billions of years, which will be named after a substance or concept (in this case cold) rather than in a modern area where fossils from the period are found (for example, Jurassic is named after Jurach).
during the cryogenic period were at least two main ice ages and maybe up to four. Glacial Deposits in Cryogenic Layers in Equatorial Paleolatitiudes (specifically Kratons Kong and KalahAri) Many scientists have led to consider the possibility of "snowballs" - the planet so cool from the oceans solidify the solid. This led to a large number of controversy in the scientific community. Many scientists doubt the geophysical viability of a completely frozen ocean. Simulations have been triggered, but such calculations will shift the limits of available computing power and sometimes radical simplistic prerequisites are necessary. For example, one study ignores the existence of continents. Some scientists have medium ground and argue about the scenario "Slushball Earth", where the oceans are covered with a large amount of sea ice, but are not frozen to the bottom.
The two confirmed main glaciation in the cryogenic period were Sturtian Glaciation (760 million years ago to 700 MyA) and Marinoan/Varanger (710/650 to 635 ma). During these gladly global temperature, it would drop at least 20 ° C, from 22 ° C (71 ° F) to approximately 2 ° C (37 ° F), and perhaps much lower, to less than -30 ° C (-22 ° F). The temperature on the poles could have been so low,that carbon dioxide could freeze into dry ice, which has a freezing point of -78.5 ° C (-109.3 ° F). Dry ice is the main component of polar ice caps Mars.
Life existed long before the cryogenic period and apparently survived over it. All plants, animals and mushrooms existed, albeit almost exclusively in a unicellular form. Under microbial mats, there is some evidence of small burrows, perhaps made by simple multicellular organisms. Small organic fossils called acritarchy were found in large quantities and diversity before the cryogenic period, but both crashed during this period. Acritarchs were isolated from cryogenic sediments, they are simply not very numerous or diverse.