Effects of strong network modifiers on Fe3+/Fe2+ in silicate melts: an experimental study
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The effect of CaO, Na2O, and K2O on ferric/ferrous ratio in model multicomponent silicate melts was investigated in the temperature range 1450–1550 °C at 1-atm total pressure in air. It is demonstrated that the addition of these network modifier cations results in an increase of Fe3+/Fe2+ ratio. The influence of network modifier cations on the ferric/ferrous ratio increases in the order Ca < Na < K. Some old controversial conceptions concerning the effect of potassium on Fe3+/Fe2+ ratio in simple model liquids are critically evaluated. An empirical equation is proposed to predict the ferric/ferrous ratio in SiO2–TiO2–Al2O3–FeO–Fe2O3–MgO–CaO–Na2O–K2O–P2O5 melts at air conditions.
KeywordsFerric/ferrous ratio Silicate melt Experiment CaO Na2O K2O
The stay of AB in Hannover was funded by the German Science Foundation (DFG project Ho 1337/30-1). We thank Eric Wolff and Renat Almeev for the electron microprobe assistance and Florian Pohl for the help in the determination of ferric/ferrous ratios in glasses. We are grateful to editor Chris Ballhaus and three anonymous reviewers for their comments and suggestions which allowed us to improve the paper. This study was partly supported by Russian Science Foundation (Grant 14-17-00491).
- Borisov AA, Shapkin AI (1990) A new empirical equation relating Fe3+/Fe2+ in magmas to their composition, oxygen fugacity, and temperature. Geochem Int 27:111–116Google Scholar
- Borisov A, Behrens H, Holtz F (2015) Effects of melt composition on Fe3+/Fe2+ in silicate melts: a step to model ferric/ferrous ratio in multicomponent systems. Contrib Min Petrol 169: Article 24Google Scholar
- Bychkov AM, Borisov AA, Khramov DA, Urusov VS (1993) Change in the immediate environment of Fe atoms during the melting of minerals (Review). Geochem Int 30:1–25Google Scholar
- Hirashima H, Yoshida T, Brückner R (1988) Redox equilibria and constitution of polyvalent ions in oxide melts and glasses. Glastech Ber 61: 283–291Google Scholar
- Ishihara S (2004) The redox state of granitoids relative to tectonic setting and earth history: the magnetite-ilmenite series 30 years later. Geological Society of America Special Papers 389: 23–33Google Scholar
- Mysen BO, Richet P (2005) Silicate glasses and melts, properties and structure. Elsevier, Amsterdam, p 544Google Scholar
- Paul A, Douglas RW (1965) Ferrous-ferric equilibrium in binary alkali silicate glasses. Phys Chem Glasses 6:207–211Google Scholar
- Shand SJ (1927) Eruptive rocks; their genesis, composition, classification, and their relation to ore deposits, with a chapter on meteorites. 1st ed. 360 p. Thomas Murby and Co., LondonGoogle Scholar
- Sukenaga S, Kanehashi K, Shibata H, Saito N, Nakashima K (2016) Structural role of alkali cations in calcium aluminosilicate glasses as examined using oxygen-17 solid-state nuclear magnetic resonance spectroscopy. Met Mat Trans 47B:2016–2177Google Scholar