New model to estimate water in the Earth's mantle
Article first published online: 3 AUG 2012
©2012. American Geophysical Union. All Rights Reserved.
Eos, Transactions American Geophysical Union
Volume 93, Issue 32, page 316, 7 August 2012
How to Cite
2012), New model to estimate water in the Earth's mantle, Eos Trans. AGU, 93(32), 316., (
- Issue published online: 3 AUG 2012
- Article first published online: 3 AUG 2012
- Cited By
- Kaapvaal craton;
- Rehoboth terrane;
- mantle water
The Earth's mantle could be holding as much water as the ocean and atmosphere combined—but in the form of defects in dry minerals, such as olivine, that make up a large fraction of the mantle. Water in mantle minerals weakens chemical bonds, affecting physical and chemical properties of the mantle, particularly viscosity and electrical conductivity. Scientists continue to debate not just the amount of water but also its distribution in the mantle. Seismic velocity profiles, typically used to map the water content of the mantle, are, in fact, not sensitive to the amount of water. An increase of 1% by weight of water in mantle minerals, i.e., from “dry” to “very wet” conditions, reduces seismic velocities by at most 1%, which is often below the detection limit. On the other hand, an increase in water content by only 0.01%, from “dry” to “damp” conditions increases electrical conductivity in mantle minerals by an order of magnitude or more, making electrical conductivity a more sensitive tool to estimate the water content of mantle minerals.