The spin state of iron in minerals of Earth's lower mantle
Article first published online: 23 JUN 2005
Copyright 2005 by the American Geophysical Union.
Geophysical Research Letters
Volume 32, Issue 12, June 2005
How to Cite
2005), The spin state of iron in minerals of Earth's lower mantle, Geophys. Res. Lett., 32, L12307, doi:10.1029/2005GL022802., , and (
- Issue published online: 23 JUN 2005
- Article first published online: 23 JUN 2005
- Manuscript Accepted: 23 MAY 2005
- Manuscript Revised: 10 APR 2005
- Manuscript Received: 23 FEB 2005
 The spin state of Fe(II) and Fe(III) at temperatures and pressures typical for the Earth's lower mantle is discussed. We predict an extended high-spin to low-spin crossover region along the geotherm for Fe-dilute systems depending on crystal-field splitting, pairing energy, and cooperative interactions. In particular, spin transitions in ferromagnesium silicate perovskite and ferropericlase, the dominant lower mantle components, should occur in a wide temperature-pressure range. We also derive a gradual volume change associated with such transitions in the lower mantle. The gradual density changes and the wide spin crossover regions seem incompatible with lower mantle stratification resulting from a spin transition.