The clues to lower mantle diamonds genesis: Role of physico-chemical experiments

Abstract

Carbonate components involved into the lower mantle diamond-parental melts provides their capability to the common formation of diamonds with oxide and silicate minerals that fits the syngenesis criterion. This capability combines congruent melting of carbonates, complete liquid miscibility of carbonate, oxide and silicate components as well as high solubility of diamond in the miscible oxide-silicate-carbonate parental melts. Therewith, diamond-producing processes are noted for their high densities of diamond nucleation and crystal growth rates. A concentration barrier of diamond nucleation is depending on the level of diamond-parental melt oversaturation with dissolved elemental carbon in respect of diamond phase. The distinguishing features of the lower mantle genesis of diamonds and associated phases have become disclosable from the physico-chemical experiments.