Oceans hotter than any today
Seawater may have been 55 to 85 degrees, and the debate over how hot is still unsettled.
- When
- Known to
- ± 200 million years
- Era
- Mesoarchean, Archean
Oxygen and silicon isotopes in Archean cherts suggest ocean temperatures far above modern values — some readings imply water near 70°C. Others argue the isotopic signal reflects changing seawater chemistry rather than heat, and that the Archean ocean was temperate. The Pongola glaciation complicates any simple hot-Archean picture, since a uniformly scalding planet should not have grown glaciers.