Geologists discover hidden water reservoir 3,000km beneath Earth's surface

Researchers have identified a hidden water reservoir located approximately 3,000 kilometers beneath the Earth's surface. The study suggests this water is likely situated near the boundary between the mantle and the liquid outer core, specifically within ultralow velocity zones identified through seismic testing.

Alfred Wilson, a geologist at the University of Leeds, notes that liquid water is a fundamental component of Earth's habitability. Beyond supporting life, water plays a critical role in lubricating the slow movement of the mantle, which facilitates tectonic cycles and helps regulate the planet's climate over geological timescales.

To investigate how water reached these depths, scientists used laser-heated diamond anvil cells to simulate the extreme temperatures and pressures found in the lower mantle. While common minerals like bridgmanite are thought to be dry, the research explores how water might be stored in deeper structures.