Fluid regime of diamond crystallisation in carbonate-carbon systems
Sokol, Alexander G.; Tomilenko, Anatoly A.; Pal’Yanov, Yury N.; Borzdov, Yury M.; Pal’Yanova, Galina A.; Khokhryakov, Alexander F.
European Journal of Mineralogy Volume 12 Number 2 (2000), p. 367 - 375
published: Mar 29, 2000
manuscript accepted: Nov 5, 1999
manuscript received: Oct 7, 1999
ArtNo. ESP147051202007, Price: 29.00 €
Abstract The gaseous phase in experiments of diamond crystallisation in the carbonate-carbon systems Li2CO3-C, Na2CO3-C, K2CO3-C, Cs2CO3-C, CaCO3-C, CaMg(CO3)2-C at P = 7 GPa and T =1 700-1750°C (using the “splitsphere” high-pressure device) was studied by means of gas chromatography. Unlike in traditional metal-carbon systems, in which diamond forms under highly reducing conditions in the presence of a methane-hydrogen fluid, crystallisation of diamond in carbonate-carbon systems occurs in the presence of a H2O-CO2-rich fluid. The results provide experimental confirmation of the possibility for diamond to crystallise in nature in a wide range of redox conditions