The system ilmenite–carbonatite–carbon in the origin of diamond: Correlation between the titanium content and diamond potential of kimberlite

Abstract

Experimental studies of melting relations in the system ilmenite–K–Na–Mg–Fe–Ca carbonatite–carbon at 8 GPa and 1600°C provide evidence for the effect of liquid immiscibility between ilmenite and carbonatite melts. It is shown that the solubility of ilmenite in carbonatitic melts is negligible and does not depend on its concentration in experimental samples within 25–75 wt %. However, carbonatite–carbon melts are characterized by a high diamond-forming efficiency. This means that the correlation between the concentration of TiO₂ and diamond content is problematic for mantle chambers and requires further, more complex, experimental studies.