A Ba- and Ti-rich mica (up to 14.0 wt% BaO and 13.1 wt% TiO 2 ) occurs in nephelinites from the Middle Atlas Volcanic Province, Morocco. The rocks show a porphyritic texture composed of olivine, Ti-rich augite, nepheline and Ti-rich magnetite. Oxyphlogopite is found in secondary assemblages consisting of zeolites, clinopyroxene and Ti-oxides. This mineral occurs mostly as euhedral to subhedral crystals lining the walls of zeolitic veinlets and cavities in the nephelinites. The coupled substitutions of (1) Ba for K in the interlayer site and Si for Al in the tetrahedral site and (2) Ti 4+ for Mg in the octahedral site and O 2− in the (OH, F) site are major mechanisms of Ba and Ti incorporation in these micas. The average structural formula, calculated on the basis of 12 (O, OH, F, Cl), is (Si 2.515 -Al 1.482 -Fe 3+ 0.003 ) 4.000 (Al 0.050 -Ti 0.661 -Fe 2+ 0.798 -Mn 0.012 -Mg 1.500 ) 3.021 (Ca 0.014 -Ba 0.398 -Na 0.066 -K 0.502 ) 0.980 O 10 (F 0.308 -Cl 0.009 -O 1.319 -OH 0.365 ) 2.001 , suggesting a combination of oxyphlogopite and oxykinoshitalite, with contribution from the hypothetical end-member “Ti-eastonite”. Ba- and Ti-rich oxymica in the nephelinites may have crystallized under the influence of Ba-rich fluids derived from nephelinitic melts during late magmatic stages. The Ba enrichment in the host nephelinites indicates a lithospheric mantle source enriched by the circulation of metasomatic fluids.

中文翻译：

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来自摩洛哥北部中阿特拉斯火山省霞石的富含 Ba 和 Ti 的氧云母

富含 Ba 和 Ti 的云母（高达 14.0 wt% BaO 和 13.1 wt% TiO 2）出现在摩洛哥中阿特拉斯火山省的霞石中。岩石呈斑状结构，由橄榄石、富钛辉石、霞石和富钛磁铁矿组成。氧金云母存在于由沸石、斜辉石和钛氧化物组成的次生组合中。这种矿物主要以自形至亚自形晶体的形式出现，排列在沸石脉壁和霞石中的空腔内。(1) 层间位置的 K 的 Ba 和四面体位置的 Si 的 Al 和 (2) 八面体位置的 Mg 的 Ti 4+ 和 (OH, F) 位置的 O 2- 的耦合取代是主要机制Ba 和 Ti 掺入这些云母中。以 12 (O, OH, F, Cl) 计算的平均结构式为 (Si 2.515 -Al 1.482 -Fe 3+ 0.003) 4.000 (Al 0.050 -Ti 0. 661 -Fe 2+ 0.798 -Mn 0.012 -Mg 1.500) 3.021 (Ca 0.014 -Ba 0.398 -Na 0.066 -K 0.502) 0.980 O 10 (F 0.308 -Cl 0.03p) 3.021 (Ca 0.014 -Ba 0.398 -Na 0.066 -K 0.502) 0.980 O 10 (F 0.308 -Cl 0.03p) 0.06-103p 3.03p 3.03p 3.03p 的组合和oxykinoshitalite，来自假设的端元“Ti-eastonite”的贡献。霞石中富含 Ba 和 Ti 的氧云母可能在晚岩浆阶段来自霞石熔体的富含 Ba 流体的影响下结晶。寄主霞石中的 Ba 富集表明岩石圈地幔源是由交代流体循环富集的。霞石中富含 Ba 和 Ti 的氧云母可能在晚岩浆阶段来自霞石熔体的富含 Ba 流体的影响下结晶。寄主霞石中的 Ba 富集表明岩石圈地幔源是由交代流体循环富集的。霞石中富含 Ba 和 Ti 的氧云母可能在晚岩浆阶段来自霞石熔体的富含 Ba 流体的影响下结晶。寄主霞石中的 Ba 富集表明岩石圈地幔源是由交代流体循环富集的。