ИСТИНА

A goal of the work was to study phase transformations and inter-phase partitioning of trace elements under high pressure melting of multicomponent diamond-forming carbonate-silicate systems doped with set of trace elements. The results are applied to evaluation of contributions to compositions of the diamond-parental carbonatite melts from the upper-mantle material and presumed metasomatic agent. The results show that the TE of the parental media are mostly the mantle peridotite components, with the parental media being depleted in medium (Ba, La, Ce, Pr, Nd, Sm, Eu, Gd) and heavy (Tb, Dy, Ho, Er, Yb, Lu, Hf) rare-earth elements relative to the primitive peridotite. The elevated contents of Sr, Nb, and Ce in the completely miscible carbonate–silicate melts might be due to the participation of “metasomatic agents” in the formation of chambers of diamond-forming carbonatite magmas.