Cryogenian
geo:time:period:cryogenianCryogenian Period (720–635 Ma): Snowball Earth events (Sturtian ~717 Ma, Marinoan ~635 Ma); global glaciation to equator; carbon isotope excursions.
Cryogenian Period (720–635 Ma): Snowball Earth events (Sturtian ~717 Ma, Marinoan ~635 Ma); global glaciation to equator; carbon isotope excursions.