期刊
EUROPEAN JOURNAL OF MINERALOGY
卷 26, 期 1, 页码 53-59出版社
E SCHWEIZERBARTSCHE VERLAGSBUCHHANDLUNG
DOI: 10.1127/0935-1221/2013/0025-2339
关键词
moissanite; silicon carbide; carboreduction; mantle redox state; thermodynamic modeling
类别
资金
- European Research Council [279790]
Grains of natural SiC, moissanite, are encountered in various geological settings. According to thermodynamic calculations and high-pressure experiments, SiC formation requires very reducing conditions, approx. 6-10 orders of magnitude in fO(2) more reducing than the present-day mantle redox state. SiC occurrences have motivated several studies but the required extremely reducing conditions remain a major inconsistency that has not been solved. It is shown here that such reducing conditions can be achieved during the ultimate steps of ascent of carbon-saturated melts, when pressure is lower than 100 bars. At these conditions, the redox buffering by carbon can impose fO(2) similar to IW-6. Conditions favorable to SiC growth can therefore be reached around carbonaceous grains during the shallow emplacement of silicate melts or kimberlites and do not necessarily imply extremely localized oxygen-depleted regions in the mantle. Such reduced conditions can also explain the presence of elemental Si and ironcarbide inclusions in association with moissanite grains.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据