• journal_title：American Mineralogist
• Contributor：Alexander Borisov ; Catherine McCammon
• Publisher：Mineralogical Society of America
• Date：2010-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2010.3217
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：95
• issue：4
• firstpage：545
• section：Articles

We conducted a Mössbauer study of synthetic glasses with anorthite-diopside eutectic composition modified with either 5 or 1 wt% Fe₂O₃ and variable amounts of silica. Glasses were synthesized in air in the temperature range 1400–1570 °C. Room-temperature Mössbauer spectra showed the presence of magnetically ordered Fe³⁺, for which a systematic fitting procedure was developed to correctly estimate Fe³⁺/Fe²⁺. At constant T-f_O2 we observed a minimum in the variation of Fe³⁺/Fe²⁺ ratio with silica that varied from 56 to 63 wt% SiO₂, depending on temperature. It was also demonstrated that the temperature dependence of the ferric/ferrous ratio [log(Fe³⁺/Fe²⁺) vs. 1/T] is essentially similar for basic and silicic melts.