Trace element composition of beryl from the Sherlovaya Gora deposit, South-Eastern Transbaikalia, Russia

Gavrilchik A. K., Skublov S. G., Kotova E. L.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2021. V. 150. N 2. P. 69-82

https://doi.org/10.31857/S0869605521020052

Full text is available on eLIBRARY.RU

Language: Russian

Abstract

The local study of distribution of trace elements (including water and halogens) in two different yellow-colored crystals of beryl (heliodor) from greisens of the Sherlovaya Gora deposit was carried out by the SIMS method. The crystals showed different growth zoning. The zoning of brightly colored heliodor (12 points of analysis) consists of increasing contents of Fe, Ti, Sc as well as Na, K, Cs, Li, water, and chlorine from the core to the rims. This zoning is caused by substitution of Al³⁺ for Fe³⁺ and Sc³⁺ or by substitution of Al³⁺ for Fe²⁺ with charge compensation provided monovalent LILE (Na, Cs, Li, K, Rb) that incorporate into beryl structural channels. Together with LILE, water and chlorine incorporate into the channels too. The zoning of transparent light colored heliodor (9 points of analysis) differs in that most of the crystal is homogeneous in composition and the change in contents of trace elements occurs only in the narrow rim. Contents of Na, Li, and Cl decrease toward the edges and negatively correlate with contents of Fe, Ti, Sc and K, Ca, Cs. This zoning is may be caused by the simultaneous crystallization of heliodor with mineral-concentrators of Na, Li, and Cl such as albite and lithium mica.

Keywords: beryl, heliodor, mineral typomorphism, trace elements, SIMS method, Sherlovaya Gora