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Djerfisherite in the Udachnaya-East pipe kimberlites (Sakha-Yakutia, Russia): Paragenesis, composition and origin
journal contributionposted on 2023-06-23, 11:02 authored by VV Sharygin, AV Golovin, NP Pohkilenko, Vadim KamenetskyVadim Kamenetsky
Djerfisherite, an unusual potassium- and chlorine-bearing sulphide K 6Na(Fe,Ni,Cu) 24S 26Cl, is found in remarkably fresh rocks of the Udachnaya-East kimberlite pipe, including several varieties of kimberlite and a kimberlite-hosted phlogopite-spinel lherzolite xenolith. In both kimberlite breccia and monticellite kimberlite djerfisherite is a common groundmass mineral. Djerfisherite is also present as a daughter phase in olivine-hosted inclusions of trapped carbonate-chloride melt and sulphide melt. The mineral is present as irregular or rounded grains (up to 80-100 Î¼m) in association with magnetite and pyrrhotite in the kimberlite groundmass, and together with carbonates, Na-K-chlorides, silicates, magnetite, sulphates and Fe-Ni-sulphides in melt inclusions. Djerfisherite in the lherzolite xenolith is mainly interstitial (up to 100 Î¼m) and commonly rims primary mantle sulphides that show clear signs of replacement. Broad compositional variations in Fe, Ni and Cu are common in djerfisherite from different occurrences of the Udachnaya-East pipe. Textural relations, heating stage experiments with melt inclusions and compositional data, suggest a late magmatic origin of djerfisherite in the Udachnaya-East kimberlite groundmass, at shallow depths and at Tâ‰¤s800Â°C. In contrast, djerfisherite in the lherzolite xenolith appears to be a product of direct precipitation from evolved kimberlite magma infiltrating into lithospheric xenoliths or reactions of evolved kimberlite fluids/melts with primary minerals in xenoliths. Â© 2007 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart.
Publication titleEuropean Journal of Mineralogy
PublisherE Schweitzerbart'sche Verlagbuchhandlung