Phengite series is a dioctahedral solid solution between two end-members of muscovite [K₁[Al₂]^VI[Al₁,Si₃]^IVO₁₀(OH)₂] and celadonite [K₁[(Fe³⁺,Al)₁,(Mg,Fe²⁺)₁]^VI[Si₄]^IVO₁₀(OH)₂], which have a hetero-valent substitution of Al^VIAl^IV ↔ (Mg, Fe)^VISi^IV. In this study, we report a hydrothermal-originated authigenic Mg-phengite-series mineral, which occurred as polycrystalline aggregates (Type 1), pore-fillings (Type 2) and well-crystallized lath form (Type 3) from the Haengmae Formation, a dolomite–pebble-bearing fine sand-sized dolostone, in South Korea. Based on micro-textural observation, three types of Mg-phengite are associated with crystalline dolomite, and are followed by calcite precipitation as pore-filling, indicating that these should be formed by the influx of a Mg-rich hydrothermal fluid after the deposition of some clastic sediments and before calcite-filling. The structural formula based on O₁₀(OH)₂ shows that the number of Mg atoms per formula unit (apfu) of Mg-phengite ranges from 0.00 to 0.70 with no Fe, which is relatively high, compared with the previously reported metamorphic phengites. In REEs mineral chemistry, the Mg-phengites are characterized by the enrichment of REEs and by the particular enrichment of LREEs in the polycrystalline aggregates of Mg-phengite. It strongly suggests that the Mg-phengite should be formed by the infiltration of the highly evolved Mg- and REEs-enriched hydrothermal fluid into the clastic sedimentary rock (Haengmae Formation) as a strata-bound form, syngenetically or during early diagenesis.

中文翻译：

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由热液成因形成的碳酸盐岩中的镁-亚硫酸盐：微观组织证据和矿物化学

变质岩系列是白云母[K ₁ [Al ₂ ] ^VI [Al ₁，Si ₃ ] ^IV O ₁₀（OH）₂ ]和青铜石[K ₁ [（Fe ³⁺，Al）]的两个末端成员之间的八面体固溶体。₁，（镁，铁²⁺）₁ ] ^VI [硅₄ ] ^IV ø ₁₀（OH）₂ ]，其具有Al的杂价取代^VI的Al ^IV ↔（镁，铁）^VI硅^IV。在这项研究中，我们报告了水热起源的自生Mg-斑云母系列矿物，它来自Haengmae组的多晶聚集体（类型1），孔隙填充物（类型2）和结晶良好的板条形态（类型3），韩国的一种白云石–含卵石的细砂白云岩。根据微观结构观察，三种类型的镁镁辉石与结晶白云岩有关，随后方解石沉淀为孔隙填充物，表明它们应由富镁热液流入后形成。一些碎屑沉积物和方解石填充之前。基于O ₁₀（OH）₂的结构式结果表明，与先前报道的变质变质锂矿相比，每摩尔Mg-菲氏石分子式（apfu）中的Mg原子数在0.00至0.70之间，而没有Fe，相对较高。在REE矿物化学中，Mg-phengits的特征是REE的富集，以及Mg-phengite的多晶聚集体中LREE的特定富集。强烈建议应通过成因结合或成岩作用早期，将高度演化的富含Mg和REEs的热液渗入碎屑沉积岩（Haengmae组）中，形成层状结合形式。