Salts from Udachnaya-East kimberlite pipe (Yakutia, Russia): occurrences and mineral composition

Last years mining activity on Udachnaya-East kimberlite pipe gave us a chance to study kimberlite breccias with abundant of halides and carbonates (Sharygin et al., 2007a, b). This water-soluble assemblage occurs as breccia cement and forms chloride xenoliths of various size and composition. Olivine phenocrysts in the breccias unaffected by serpentinization include complex (carbonates + sulfates + chlorides + gas) secondary inclusions trapped at P<1kbar and T≤800oC (Golovin et al., 2007). Inclusions of saline melts in halite xenoliths show its high temperature water-free origin (Grishina et al., 2007). Similar Sr–Nd–Pb isotope data of salt xenoliths, groundmass silicates and groundmass water leachate imply a comagmatic origin of the chlorides with parental kimberlite magma (Kamenetsky et al., 2004, 2006; 2007a, b; Maas et al., 2005). Salts from this pipe have the same δCl value as mantle, crust and carbonaceous chondrites (Sharp et al., 2007). By Sharygin’s opinion, carbonate-chloride and chloride xenoliths could be fragments of evaporites that underwent thermometamorphism from kimberlitic melt (Sharygin et al., 2007b). Salt xenoliths occurrences and mineral composition are described insufficiently, however, and that is the target of this contribution.