First find of mannardite in Russia

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Marco E. Ciriotti
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First find of mannardite in Russia

Messaggio da Marco E. Ciriotti » ven 27 apr, 2018 12:46

▪ Reznitsky, L.Z., Sklyarov, E.V., UshchapovskayaZ.F., and I. G. Barash, I.G. (2018) The First Find of Mannardite in Russia. Doklady Earth Sciences, 479, 397-400.

Mannardite was found in a type of Cr–V–bearing metamorphic rock of the Slyudyanka complex (South Baikal region). The X-ray data of the mineral are recalculated for three scenarios taking into account possible variations of the mannardite structure. The mean chemical composition is as follows (14 analyses, wt %): 0.11 SiO2, 52.08 TiO2, 6.19 VO2, 13.51 V2O3, 5.50 Cr2O3, 0.24 Al2O3, 0.16 Fe2O3, 0.05 MgO, 20.09 BaO, 2.09 H2O (the H2O, VO2, and V2O3 contents are recalculated). The formula of the mean composition is (Ba1.06H2O0.94)(Ti5.27Si0.21V4+0.61V3+1.45Cr0.59Fe0.02Mg0.01)O16. Mannardite is characterized by the presence of different valent V. The mineral can be hydrous with molecular H2O or hydroxylion in tunnels or anhydrous. Mannardite can be considered an indicator of the hydroxyl or oxygen regime of petrogenetic processes.
Marco E. Ciriotti

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