Kinoshitalite with a high magnesium content in sulphide-rich marbles from the Rožná uranium deposit, Western Moravia, Czech Republic
|Original title:||Kinoshitalite with a high magnesium content in sulphide-rich marbles from the Rožná uranium deposit, Western Moravia, Czech Republic|
|Authors:||Hana Doležalová, Stanislav Houzar, Zdeněk Losos, Radek Škoda|
|Field:||Geology and mineralogy|
|Type:||Article in Periodical|
|Keywords:||kinoshitalite; Ba-micas; sphalerite; marble; Rožná uranium deposit; Moldanubicum; Bohemian Massif; Czech Republic|
Ba-micas including magnesian kinoshitalite (XMg more than 0.99) were found in sulphide-rich dolomite marbles at the Rožná uranium deposit, Moldanubicum, Czech Republic. The Ba-micas (phlogopite with Ba > 0.280 apfu and kinoshitalite with Ba from 0.869 to 1.244 apfu) are Mn, Fe and Ti-poor in comparison to other Ba-micas described up to date. The main substitution mechanism in Ba-micas is (Ba2+,Ca2+) (Al3+) (K+,Na+)-1 Si4+-1. Relatively high content of Mn in silicates and carbonates from the host marble is in contrast to the chemistry of Ba-micas. Barium and manganese show distinct behaviour during metamorphism. Manganese and iron were probably partitioned to metamorphic sphalerite and pyrrhotite relative to (Mn, Fe)-poor Ba-micas. Barium concentrated in mica minerals and the system was evidently Ba-depleted in late stages.