snowballearth.org: Snowball Earth The Snowball Earth website examines the evidence and theory behind the snowball earth hypothesis, the idea that the globe was covered by ice for long periods roughly 2220, 710 and 636 million years ago. Keyword: cryogenian , extreme weather , ice age , low-latitude glaciation , precambrian , proterozoic , snowball earth www.snowballearth.org/ Add Site or Add URL to Submit Site to the cryogenian Directory |