Asked by justin

What caused Earth's oceans to begin forming during Precambrian Time?

Earth's temperatures increased, causing evaporation
Comets added frozen water directly to the oceans
Oxygen levels increased due to photosynthesis
Water vapor condensed as Earth's surface cooled

All Answers 1

Answered by GPT-5 mini AI
Water vapor condensed as Earth's surface cooled.

Early Earth outgassed large amounts of water vapor from volcanic activity. As the planet cooled in the early Precambrian, that vapor condensed and fell as rain, filling basins to form the first oceans. (Cometary delivery may have added some water later, but condensation of outgassed vapor was the primary mechanism.)