Study suggests water reached Earth's mantle 3 billion years ago, fueling ancient volcanism

Ancient rocks recovered from Western Australia have revealed evidence that water penetrated deep into the Earth’s mantle more than three billion years ago, predating the full development of modern plate tectonics. The study, conducted by a team of geologists and geochemists, identified mineral signatures and isotopic compositions indicative of water-rich crustal material that was incorporated into the mantle during the Archean eon.

The researchers propose a mechanism they term “dripduction,” in which fragments of hydrated crust periodically detached and sank into the underlying mantle, releasing water that lowered melting points and facilitated magma generation. This process would have contributed to early volcanic activity and may have influenced the thermal and chemical evolution of the planet’s interior. The findings provide a new perspective on the role of water in shaping Earth’s early geodynamic behavior and suggest that deep‑mantle water cycles operated long before the establishment of contemporary tectonic regimes.