Experimental Modeling of C-0-Forming Processes Involving Cohenite and CO2-Fluid in a Silicate Mantle

Bataleva, Yu. V.; Palyanov, Yu. N.; Borzdov, Yu. M.; Bayukov, O. A.; Sobolev, N. V. Source: DOKLADY EARTH SCIENCES, 483 (1):1427-1430; 10.1134/S1028334X18110016 DEC 2018

Experimental studies were performed in the Fe3C–SiO2–(Mg,Ca)CO3 system (6.3 GPа, 1100–1500°C, 20–40 h). It is established that the carbide–oxide–carbonate interaction leads to the formation of ferrosilite, fayalite, graphite, and cohenite (1100 and 1200°С), as well as a Fe–C melt (1300°С). It is determined that the main processes in the system are decarbonation, redox-reactions of cohenite and a CO2-fluid, extraction of carbon from carbide, and crystallization of metastable graphite (± diamond growth), as well as the formation of ferriferous silicates. The interaction studied can be considered as a simplified model of the processes that occur during the subduction of oxidized crustal material to reduced mantle rocks.