Rutile enriched with chalcophile elements (Sb, Sn, Te) and Ti-rich varieties of tripuhyute and cassiterite from sublimates of active fumaroles at the Tolbachik volcano (Kamchatka, Russia)

Sandalov F. D., Pekov I. V., Koshlyakova N. N., Yapaskurt V. O., Agakhanov A. A., Sidorov E. G., Britvin S. N.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2020. V. 149. N 2. P. 22-41

https://doi.org/10.31857/S0869605520020070

Language: Russian

Abstract

The paper contains data on rutile, tripuhyite and unusual Ti-rich cassiterite found in sublimates of active fumaroles at the Tolbachik volcano, Kamchatka, Russia. Unlike rutile from other geological formations, fumarolic rutile is enriched with admixed chalcophile elements. It contains (up to, wt %): Sb2O5 35, SnO2 59, TeO3 11.3, CuO 1.9, and ZnO 0.4, as well as up to 18 wt % Fe2O3. So high contents of tin and copper were not reported for rutile in literature before, as well as the presence of tellurium in this mineral. Cassiterite with 19–23 wt % TiO2 also represents a novel variety. Hexavalent tellurium occurs in rutile together with trivalent iron according to the substitution scheme Te⁶⁺ + 2Fe3+ → 3Ti⁴⁺. Being isostructural minerals, rutile, tripuhyite and cassiterite form a ternary isomorphous system with several gaps in fumaroles of the Tolbachik volcano. These minerals were formed at temperatures not lower than 350 °С, most likely as a result of the interaction between hot volcanic gas (source of chalcophile elements) and basalt (source of Ti).

Keywords: rutile, tripuhyite, cassiterite, titanium, tin, antimony, tellurium, isomorphism, fumarole, Tolbachik volcano