Title:
Nature and role of iron in the Earth's lower mantle: laser-heated diamond anvil cell study

Abstract:
As the largest layer in the Earth, the lower mantle and the chemical/physical properties of lower mantle minerals are important for understanding the Earth's bulk chemistry, structure and dynamics. It is widely accepted that the lower mantle consists mainly of bridgmanite and ferropericlase with a substantial amount of iron impurity, which is considered to have a strong effect on the physical properties of the minerals. I have studied physical and chemical properties of iron-bearing lower mantle minerals based on high pressure experiments using laser-heated diamond-anvil cell (LHDAC). Particularly, I have investigated (1) valence state and partitioning of iron in the Earth's lower mantle using transmission electron microscopy and (2) effect of iron on the electrical conductivity of lower mantle mineral. In this talk, I will summarize my experimental results and discuss about the nature and role of iron in the Earth's lower mantle.