SNOWBALL EARTH
www.snowballearth.org
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.
关键词：snowball earth, ice age, low-latitude glaciation, Proterozoic, Cryogenian, Precambrian, extreme weather, origins of life