Melt Inclusions in Chromium Spinel of Kimberlites of the Zapolyarnaya Pipe, Upper Muna Field, Siberian Craton

Abstract

Abstract: The results of study of primary melt inclusions in сhromium spinel of kimberlites of the middle Paleozoic Zapolyarnaya pipe (Upper Muna field, Siberian Craton) are presented. The inclusions are composed of an aggregate of daughter minerals: calcite, dolomite, nyerereite Na2Ca(CO3)2, gregoryite (Na,K)2CO3, northupite Na3Mg(CO3)2Cl, bradleyite Na3Mg(PO4)(CO3), apatite, chlorides (sylvite and/or halite), phlogopite, olivine, magnetite, and djerfisherite K6(Fe,Cu,Ni)25S26Cl. Carbonates are dominant over silicates. The assemblage of daughter minerals in the inclusions indicates a Si-depleted and alkali- (both Na and K) and CO2-rich, probably, alkali-carbonatitic parental kimberlite melt for the Zapolyarnaya pipe.