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News Release 10-037
Scientists Find Signs of "Snowball Earth" Amidst Early Animal Evolution
New evidence hints at global glaciation 716.5 million years ago
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Two ideas exist on the progression of glaciation on Earth from 716.5 to 630 million years ago. Current evidence suggests the top version: a dynamic snowball Earth in which at least two long-lived glaciations happened during which communication between the ocean and the atmosphere was cut off. In this scenario, as CO2 built up, a hot-house effect ensued resulting in an ice-free planet at 670 and 630 million years ago.
Credit: Zina Deretsky, National Science Foundation
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Glaciation at tropical latitudes provides evidence of a "snowball Earth."
Credit: Francis Macdonald
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Ancient tropical rocks now found in northwestern Canada show evidence of past ice cover.
Credit: Francis Macdonald
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Scientists wonder if a long-ago "snowball Earth" stimulated the evolution of animals.
Credit: Francis Macdonald
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The researchers' findings appear in the March 5, 2010 issue of the journal Science.
Credit: Copyright AAAS 2010
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