‘Waterworld’ Earth preceded late rise of continents, scientist proposes

Expansion of dry land may have enabled Cambrian explosion

ocean

WATER WORLD  The continents rose above sea level only a few hundred million years ago, a new proposal states. Before that time, Earth’s surface was mostly covered by water.

Tfioreze/Wikimedia Commons (CC BY-SA 3.0)

SAN FRANCISCO — Earth may have been a water world for much of its history, a new proposal contends.