Experimental investigation of diamond formation conditions in the C-H-O system under high pressure and temperature

Abstract

High-temperature and high-pressure experiments were performed to investigate the formation conditions of diamond in the C-H-O system under the mantle conditions of giant icy planets such as Neptune and Uranus. The results show that diamond formation through the dissociation of methane occurs above 1500 K between 2 and 90 GPa. This suggests that diamond potentially forms from methane in the icy mantle of Neptune and Uranus.