High-aluminous, fluoro-titanites (~ 6.8–11.5 wt% Al₂O₃, up to ~ 3.8 wt% F) from a suite of calc-silicate granulites in the Chotanagpur Granite Gneiss Complex, East Indian shield, were examined to investigate the controls on Al incorporation in titanite. The studied high aluminous titanites have the third highest Al content (X_Al= up to ~ 0.46), reported from low to medium-pressure rocks till date. These titanites develop in three different associations (association 1, 2 and 3) along with the F-bearing hydrous minerals like amphibole or vesuvianite. These three associations occur as veins and patches close to the pegmatitic veins that intruded the granulite facies calc-silicate rocks. The titanite in the host calc-silicate rock (association 4), away from the pegmatite veins, preserves an anhydrous assemblage: garnet-clinopyroxene-plagioclase and low Al titanite (Al₂O₃ = 3.4–3.8 wt%, F ~ 0.8 wt%). Integrating field features, petrography and textural modeling, it is suggested that infiltration of F-bearing aqueous fluid, presumably derived from the pegmatites, into the host calc-silicate rock was responsible for the partial destabilization of the anhydrous assemblage 4, and formation of the Al-F rich titanite bearing assemblages 1–3. The published information and close proximity of the association 1–4 outcrops suggest that the infiltration-driven growth of Al-F-rich titanite occurred virtually under isothermal-isobaric conditions (5.5–6.5 kbar and 650–750 °C). The titanite in associations 1–3 show a positive correlation between Al₂O₃/TiO₂ and F/OH indicating the substitution Ti^+ 4 +O²⁻ = Al^+ 3+ (F + OH)⁻. Based on the findings of the present study, combined with the published information on titanite chemistry, it is argued that the f_F2 present in the system plays a dominant role, if not the most important, in regulating the extent of Al substitution in titanites, in addition to pressure, temperature or coexisting mineral assemblage.

对东印度地盾 Chotanagpur 花岗岩片麻岩复合体中的一组钙硅酸盐麻粒岩中的高铝氟钛矿（~ 6.8–11.5 wt% Al ₂ O ₃ ，高达~ 3.8 wt% F）进行了检查以进行调查对钛矿中Al掺入的控制。所研究的高铝钛矿具有第三高的Al含量（X _Al= 高达 ~ 0.46)，迄今为止从低压到中压岩石都有报道。这些钛铁矿以三种不同的组合（组合 1、2 和 3）与含 F 含水矿物（如角闪石或维苏威石）一起发育。这三个组合以靠近侵入麻粒岩相硅酸钙岩石的伟晶岩脉的脉和斑块形式出现。远离伟晶岩脉的主钙硅酸盐岩石（组合 4）中的钛铁矿保留了无水组合：石榴石-单斜辉石-斜长石和低铝钛矿（Al ₂ O ₃ = 3.4–3.8 重量％，F ~ 0.8 重量％)。结合野外特征、岩相学和结构建模，表明可能源自伟晶岩的含 F 水性流体渗透到主体硅酸钙岩石中是导致无水组合 4 部分不稳定以及形成富 Al-F 钛矿轴承组合 1-3。已发表的信息和关联 1-4 露头的接近表明富含 Al-F 钛矿的渗透驱动生长实际上发生在等温等压条件下（5.5-6.5 kbar 和 650-750 °C）。组合 1-3 中的钛矿显示 Al ₂ O ₃ /TiO ₂和 F/OH 之间呈正相关，表明取代 Ti ^{+ 4} +O ²⁻= Al ^{+ 3} + (F + OH) ⁻。根据本研究的结果，结合已发表的钛酸盐化学信息，有人认为系统中存在的f _F2在调节钛酸盐中的 Al 取代程度方面起着主导作用，如果不是最重要的话，除了压力、温度或共存矿物组合。