Snowball Earth describes a theory that for millions of years the Earth was entirely smothered in ice, stretching from the poles to the tropics. This freezing happened over 650 million years ago in the Pre-Cambrian, though it's now thought that there may have been more than one of these global glaciations. They varied in duration and extent but during a full-on snowball event, life could only cling on in ice-free refuges..
Kickstart your day with a good read!⚡️Did explosive underwater volcanos end ‘Snowball Earth’? – CSMonitor.com http://mymullings.com/2016/01/20/did-explosive-underwater-volcanos-end-snowball-earth-csmonitor-com/
Earth was a frozen Snowball when animals first evolved
Rock weathering may have led to 'Snowball Earth' (Phys.org) —A team of researchers conducting a field study in the Mackenzie Mountains in northwest Canada is suggesting rock weathering almost a billion years ago, may have led to the entire planet being encased in ice for 55 million years. The multi-national teams subsequent analysis of rock samples they retrieved and how doing so led to what they believe is an explanation of one of the most dramatic instances of climate change on record.