The partition coefficients of Sn (tin) between minerals and silicate melts are vital for understanding the Sn enrichment during magmatic processes related to tin-granites. However, experimentally determined values remain scarce due to the difficulty in avoiding severe Sn loss to noble metal capsules. In this study, we performed mineral/melt Sn partitioning experiments at 0.5–1.0 GPa, 850–1000 °C, and O of FMQ + 8 to ∼ FMQ − 1. The Os were imposed by solid buffers of Ru–RuO, Re–ReO, Ni–NiO, Co–CoO and graphite using three improved capsule designs: 1) a single sample capsule (Pt) for the Ru–RuO buffered runs, 2) double capsules with PtRh as outer capsule and Re as inner sample capsule for the graphite and Re–ReO buffered runs, and 3) triple capsules for the Co–CoO and Ni–NiO buffered runs, with PtRh (or Au) as outer capsule, Re lined Pt as inner sample capsule. These new capsule designs avoided significant Sn loss and enabled us to obtain accurate at a controlled O. The experimental results show that values are 0.08–12.66 for amphibole, 0.01–5.55 for biotite, 0.09–10.39 for clinopyroxene, 0.004–0.97 for orthopyroxene, < 0.01 for olivine, 1.34–108.43 for Ti-magnetite, 0.04–4.17 for spinel and 0.10–0.64 for ilmenite. The large variation of for each mineral was mainly ascribed to the effect of O, which results in an arresting decrease of with decreasing O. Under the reducing conditions (O < FMQ), Sn is highly incompatible ( < 0.1) in almost all the minerals. Modeling results indicate that partial melting at low O conditions results in Sn enrichment in the derived magma, while subsequent high degree of fractional crystallization is also important for the Sn enrichment in the residual melt. The experimental and modeling results thus explain why major primary tin deposits are always related to reducing and highly fractionated granites.

中文翻译：

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锡在镁铁质矿物、铁钛氧化物和硅酸盐熔体之间的分配：对岩浆过程中锡富集的影响

锡（锡）在矿物和硅酸盐熔体之间的分配系数对于了解与锡花岗岩相关的岩浆过程中锡的富集至关重要。然而，由于难以避免贵金属胶囊中锡的严重损失，实验确定的值仍然很少。在本研究中，我们在 0.5–1.0 GPa、850–1000 °C 和 O 为 FMQ + 8 至 ~ FMQ − 1 的条件下进行了矿物/熔体 Sn 分配实验。Os 是由 Ru–RuO、Re– 固体缓冲剂施加的。 ReO、Ni-NiO、Co-CoO 和石墨使用三种改进的胶囊设计：1) 用于 Ru-RuO 缓冲运行的单样品胶囊 (Pt)，2) 双胶囊，其中 PtRh 作为外胶囊，Re 作为内样品胶囊，用于石墨和 Re-ReO 缓冲运行，以及 3) 用于 Co-CoO 和 Ni-NiO 缓冲运行的三重胶囊，其中 PtRh（或 Au）作为外胶囊，Re 衬里 Pt 作为内样品胶囊。这些新的胶囊设计避免了显着的 Sn 损失，并使我们能够在受控的 O 下获得准确的结果。实验结果表明，角闪石的值为 0.08–12.66，黑云母的值为 0.01–5.55，单斜辉石的值为 0.09–10.39，斜方辉石的值为 0.004–0.97，橄榄石 < 0.01，钛磁铁矿 1.34–108.43，尖晶石 0.04–4.17，钛铁矿 0.10–0.64。每种矿物的较大变化主要归因于O的影响，这导致随着O的减少而显着下降。在还原条件下（O < FMQ），Sn在几乎所有矿物中都是高度不相容的（< 0.1） 。模拟结果表明，低氧条件下的部分熔融导致衍生岩浆中锡的富集，而随后的高度分异结晶对于残余熔体中锡的富集也很重要。因此，实验和模拟结果解释了为什么主要的原生锡矿床总是与还原和高度分异的花岗岩有关。