Stronadelphite from the alkaline rocks of the Konder Massif (Khabarovsk krai)

Osipov A. S., Antonov A. A., Bocharov V. N., Vlasenko N. S.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2021. V. 150. N 3. P. 67-78

https://doi.org/10.31857/S0869605521030072

Full text is available on eLIBRARY.RU

Language: Russian 

Abstract

This paper presents the mineralogical characteristics of stronadelphite Sr₅(PO₄)₃F found in the eudialyte-aegirine-albite rocks of the Konder alkaline-ultrabasic massif (Khabarovsk krai). The mineral forms xenomorphic individuals up to 400 × 150 micrometers. It is associated with eudialyte, lamprophyllite, barytolmaprophyllite, microcline, titanite, nepheline, strontium-rich fluorapatite and other accessory minerals. Stronadelphite crystals are colourless and translucent. The chemical composition (formula is calulated based on 25 charge units) is (Sr_4.21Ca_0.61Ba_0.07Na_0.07Fe_0.05)_5.01(P_3.01O_11.93)F_1.14. In chemical composition, the mineral is similar to stronadelphite from alkaline complexes of Kola Peninsula. The mineral identification was confirmed by the electron backscattered diffraction (EBSD) method. The crystallization of the mineral during the low-temperature hydrothermal alteration of alkaline rocks is assumed.

Keywords: stronadelphite, Sr-bearing fluorapatite, alkaline rocks, Konder massif, alkaline-ultrabasic complex