Inclusions in chloride xenoliths from the Udachnaya-East Kimberlite

• Published in: Geochemistry international Vol. 52; no. 7; pp. 595 - 603
• Main Authors: Grishina, S. N., Polozov, A. G., Smirnov, S. Z., Mazurov, M. P., Goryainov, S. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.07.2014; Springer Nature B.V
• Subjects: Cambrian; Earth and Environmental Science; Earth Sciences; Fluid dynamics; Geochemistry; Isotopes; Magma; Mineralogy; Pipes; Salts; Sedimentary rocks; Short Communications; chlorides; kimberlites; xenoliths; inclusions
• ISSN: 0016-7029; 1556-1968
• DOI: 10.1134/S0016702914050048

The wide occurrence of halite at deep levels of the Mir and Udachnaya pipes in Sakha Yakutia has long been established [1, 2], but the problem of the source of salts in kimberlites is still a topic of debate. Recently, peculiar chloridecarbonate and chlorite enclaves were described in fresh kimberlites from the Udachnaya East pipe, and their possible magmatic origin has been actively discussed [39]. Based on the similarity of the SrNdPb isotopic characteristics of salt xenolith, sil icates, and water extracts from the kimberlite ground mass, it was concluded that the chloride enclaves are cognate with the primary kimberlite magma [4, 9]. However, in our opinion, the available data cannot be unambiguously interpreted. The occurrence of the kim berlites in the platform cover comprising thick salt bearing Cambrian sequences suggests that xenoliths of sedimentary rocks could be trapped by the kimberlites. The interaction of salt xenoliths and formation solu tions (brines) with kimberlite melt in the upper part of the sedimentary sequence could significantly affect the development of the structure of some kimberlite pipes [1012]. It should be noted that the extensive drilling of the country rocks near the Udachnaya did not reveal the presence of salt bearing sequences that could be responsible for the appearance of chloride and chlo ridecarbonate xenoliths in the pipe. Therefore, the elucidation of the nature of these xenoliths and estima tion of the contribution of crustal and mantle compo nents to their formation are important problems requiring a combined approach. With this in mind, we investigated the association of fluid and mineral inclusions for the determination of the formation conditions of chloride xenoliths from the Udachnaya East kim berlite.