The results of experimental studies are presented for reactions in the orthopyroxene–garnet–phlogopite system in the presence of H2O–KCl fluid at 3–5 GPa and 900–1000°C, which model the processes of phlogopite formation in garnet peridotites and pyroxenites during alkaline metasomatism of the upper mantle. The experiments demonstrated regular variations in the composition of garnet, pyroxenes, and phlogopite depending on the KCl content of the fluid. With increasing KCl content of the fluid, enstatite and garnet become unstable, the Al2O3 content of enstatite decreases, and the amount of grossular and knorringite components in garnet are maximum at a KCl content of ~10 mol %. Our results illustrate well the regular variations in the compositions of the coexisting minerals and their zoning in phlogopite-bearing peridotites of the lithospheric mantle.

中文翻译：

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H2O-KCl 流体存在下的邻辉石-石榴石系统中金云母的形成在地幔交代过程中的应用

实验研究结果展示了在 3-5 GPa 和 900-1000°C 的 H2O-KCl 流体存在下在斜方辉石-石榴石-金云母系统中的反应，模拟了石榴石橄榄岩和辉石岩中金云母的形成过程上地幔的碱性交代作用。实验表明，石榴石、辉石和金云母的成分随流体中 KCl 含量的不同而有规律地变化。随着流体中 KCl 含量的增加，顽火石和石榴石变得不稳定，顽火石中的 Al2O3 含量降低，在 KCl 含量为 10 mol% 时，石榴石中粗晶和球状菱镁矿的含量最大。