Snowball Earth: the Marinoan
The planet freezes over a second time, then thaws in a few thousand years.
- When
- —
- Duration
- 15 million years
- Known to
- ± 5 million years
- Era
- Neoproterozoic, Proterozoic
The Marinoan glaciation runs from about 650 to 635 million years ago, with radioisotopic dating constraining the snowball itself to roughly four million years. Its end was abrupt: deglaciation took a few thousand to a few tens of thousands of years, as runaway greenhouse warming melted a world-covering ice sheet. The transition is recorded in cap carbonates draped over glacial debris on every continent.