Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. The most academically referred period of such global glaciation is believed to have occurred sometime before 650 mya during the Cryogenian period. The Snowball Earth is a geohistorical hypothesis that proposes during one or more of Earth's icehouse climates, the planet's surface became entirely or nearly entirely frozen with no liquid oceanic or surface water exposed to the atmosphere. The Huronian glaciation, is not shown, there is a lack of any significant evidence for a Snowball Earth during the time period. As for the Kaigas, its very existence is doubted by some. ĭating of pre- Gaskiers glaciations is uncertain.
