Variations in the Concentration of Ta and Nb in a Peraluminous Haplogranite High-Fluorine Melt in Relation to the Change in the Association of Liquidus Phases
- Authors: Alferyeva Y.O.1, Gramenitskiy E.N.1, Shchekina T.I.1, Zinovieva N.G.1
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Affiliations:
- Department of Geology, Moscow State University
- Issue: Vol 74, No 4 (2019)
- Pages: 393-400
- Section: Article
- URL: https://journals.rcsi.science/0145-8752/article/view/175016
- DOI: https://doi.org/10.3103/S0145875219040033
- ID: 175016
Cite item
Abstract
A series of experiments were carried out in the peraluminous part of the haplogranite high fluorine system SiO2–Al2O3–Na2O–Li2O–F at a temperature of 700°C, a pressure of 100 МPa, a water content of 10 wt %, and with the addition of ~1 wt % Ta and Nb. Two types of equilibrium phase associations were obtained: (1) an aluminosilicate melt–topaz–quartz–Ta-Nb phase and (2) an aluminosilicate melt–brine aluminofluorine melt–cryolite. The maximum content of Ta and Nb in the silicate melt of the first type is ~0.29 and 0.35 wt %, respectively. The silicate melt of the second type is characterized by an almost four-fold content of these metals (1.27 and 1.21 wt %, respectively), without reaching saturation by the Ta–Nb phase. A similar jump in the total amount of Ta and Nb in genetically related highly differentiated rocks was observed for topaz- and cryolite-bearing granite massifs in the Piting Province (Brazil).
About the authors
Ya. O. Alferyeva
Department of Geology, Moscow State University
Author for correspondence.
Email: YanaAlf@ya.ru
Russian Federation, Moscow, 119991
E. N. Gramenitskiy
Department of Geology, Moscow State University
Author for correspondence.
Email: engramen@geol.msu.ru
Russian Federation, Moscow, 119991
T. I. Shchekina
Department of Geology, Moscow State University
Author for correspondence.
Email: t-shchekina@mail.ru
Russian Federation, Moscow, 119991
N. G. Zinovieva
Department of Geology, Moscow State University
Author for correspondence.
Email: nzinov@mail.ru
Russian Federation, Moscow, 119991