Abstract—

The materials on the geology, geochemistry, and mineralogy of the differentiated body of the Misaelga Complex located in the Taratash metamorphic complex on the western slope of the Southern Urals are reported. The performed studies show that the distribution of PGEs and gold along the section of a differentiated body indicates its asymmetric structure. Comparative analysis of the normalized contents of noble metals in rocks of the complex and picrite of the western slope of the Southern Urals and the adjacent part of the East European Platform shows that the rocks are characterized by general tendencies, namely, the predominance of Pd over Pt and the “rhodium anomaly.” The REE distribution in rocks of the complex is characterized by their “inert” behavior upon intrachamber melt differentiation. The residual melt became sharply enriched in the entire group of REE only at the final stages. Detailed mineralogical analysis of silicates and aluminosilicates allowed us to calculate the P–T parameters of their crystallization: intratelluric olivine, 1472°C; olivine from the groundmass, 1050–1183°C; pyroxenes, 1071–1073°C; amphibole, T = 950–1045°C, P = 4.0–7.4 kbar. Variations in the chemical composition of the major rock-forming minerals and the internal structure of the differentiated body are satisfactorily described by the fractional crystallization model for the mechanism of directed crystallization with gravitational precipitation of olivine, olivine + clinopyroxene, and early-generation ore minerals at the initial stages of the massif’s formation. It is shown that the generalized process of the sulfide and Fe–Ti mineralization upon melt differentiation in the intermediate chamber includes crystallization of a sulfide and Fe–Ti melt depending on its composition; crystallization of iss in the form of intermediate compounds, chrome–magnetite, and Cr–Mg-ilmenite, as well as compositional evolution of pentlandite towards Co-bearing varieties. At the final stage, the decomposition of Fe–Ti-solid solutions with different numbers and compositions of coexisting phases occurs.

中文翻译：

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中室熔体分异形成硫化物-氧化物矿化的条件与机制——以南乌拉尔西坡侵入体为例

摘要-

报道了位于南乌拉尔西坡塔拉塔什变质杂岩中的Misaelga杂岩分化体的地质、地球化学和矿物学资料。已进行的研究表明，PGE 和金沿分化体截面的分布表明其不对称结构。对南乌拉尔西坡与东欧地台邻区杂岩和苦铁矿岩石中贵金属的归一化含量对比分析表明，岩石具有普遍的趋势，即Pd占优势。 Pt 和“铑异常”。复合体岩石中 REE 分布的特征在于其在室内熔体分化时的“惰性”行为。仅在最后阶段，残余熔体在整个 REE 组中才急剧富集。硅酸盐和铝硅酸盐的详细矿物学分析使我们能够计算出其结晶的P-T参数：碲内橄榄石，1472°C；来自地层的橄榄石，1050–1183°C；辉石，1071–1073°C；闪石，T = 950–1045°C，P= 4.0–7.4 kbar。橄榄石、橄榄石+单斜辉石、早生矿石矿物重力沉淀定向结晶机理的分级结晶模型，较好地描述了主要成岩矿物化学成分和分化体内部结构的变化在地块形成的初始阶段。结果表明，硫化物和 Fe-Ti 矿化在中间室熔体分异时的一般过程包括硫化物和 Fe-Ti 熔体的结晶，这取决于其成分；iss 以中间化合物、铬磁铁矿和铬镁钛铁矿的形式结晶，以及镍铬铁矿向含钴品种的成分演变。在最后阶段，