Indicator reactions of K and Na activities in the upper mantle: Natural mineral assemblages, experimental data, and thermodynamic modeling

详细信息    查看全文

• 作者：O. G. Safonov ; V. G. Butvina
• 关键词：mantle ; mantle metasomatism ; K and Na activities ; peridotite ; eclogite ; experiment ; thermodynamic modeling
• 刊名：Geochemistry International
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：54
• 期：10
• 页码：858-872
• 全文大小：1,426 KB
• 刊物主题：Geochemistry;
• 出版者：Springer US
• ISSN：1556-1968
• 卷排序：54

文摘

The paper presents a review of data on mineral assemblages and reactions that are potential indicators of K and Na activities in upper mantle fluids and melts modifying upper mantle rocks in the course of mantle metasomatism. Results of experimental modeling of these reactions are discussed. These data are utilized to calculate phase reactions in $$\log \left( {{a_{{H_2}O}}} \right) - \log \left( {{a_{{K_2}O}}} \right)and\log \left( {{a_{{H_2}O}}} \right) - \log \left( {{a_{N{a_2}O}}} \right)$$ space by minimizing the Gibbs free energy (constructing pseudosections). The calculations of this type make it possible to estimate variations in K and Na activities in processes modifying upper mantle rocks, to predict successions of mineral assemblages that are formed when these parameters vary, and to compare metasomatic processes in rocks of various composition. The approach is illustrated by examples of peridotite and eclogite xenoliths in kimberlite and alkaline basalt.Keywordsmantlemantle metasomatismK and Na activitiesperidotiteeclogiteexperimentthermodynamic modelingOriginal Russian Text © O.G. Safonov, V.G. Butvina, 2016, published in Geokhimiya, 2016, No. 10, pp. 893–908.