Crystal chemistry of dense silicates at pressures and temperatures relevant for Earth lower mantle

Carbon as a point of interest

Global carbon cycle has a great impact on the climate changes, being responsible for example in the past for NeoProtezoic “snowball” Earth and Cretaceous warm period. While quantity of carbon on our planet is still uncertain, there is general consensus that deep Earth is the main reservoir of carbon-bearing compounds. The lower mantle mainly consists of high-pressure phases silicates and oxides, making these compounds important candidates for studies possible reactions with carbon-bearing materials, or hosts for dissolved carbon.

Research on geophysically important materials

Experimental investigation of possible reactions between carbon-bearing phases and deep mantle silicates and oxides requires accurate knowledge of high-pressure high-temperature behavior of all these phases. A series of recent studies showed that been chemically quite simple, under extreme conditions iron oxides could appear in a wide variety of crystal structures and iron carbonate could form previously unknown tetracarbonates. We investigate the behavior of geophysically important materials (with a focus on crystal chemistry of dense silicates) at pressures and temperatures relevant for Earth lower mantle. Our results indicate that interplay between ferrous and ferric iron, oxygen, and carbon define geochemistry of last one.