The Neoarchean U-Th-Pb (SHRIMP-II) age of 2718 ± 7 Ma was established for the large copper–nickel Allarechka deposit located in the Kola–Norwegian region of the Fennoscandian shield. The deposit is associated with metamorphosed and deeply eroded volcano-plutonic complexes, which are the age and formational analogues of the Neoarchean greenstone belts. The compositional similarity of hyperbasites of the Allarechka ore district and host metavolcanic rocks of the Annama Formation with komatiite–tholeiitic metavolcanic rocks of the similar age of the Ura Guba–Kolmozero–Voron’ya greenstone belt suggests that they are ascribed to the komatiite–tholeiite volcanoplutonic series, the parental high-Fe komatiite melts of which were derived by partial melting of depleted upper mantle ε_Nd(t) = +7.0 ± 0.4) at high PT parameters. The petrographic and geochemical composition of ore peridotites indicates that they are a cumulate formed by fractionation of Ol + Opx ± Pl, Mag from the primary high-Fe komatiite melt in a shallow (P ~ 4 kbar) magma chamber at a liquidus temperature of at least 1200°С. The absence of a significant crustal contamination of the hyperbasites by Mesoarchean TTG-complexes is proved by the trace and rare-earth element geochemistry, the Nd isotopic composition, as well as by the homogeneous morphology and isotopic composition of the accessory magmatic zircon. In contrast, Re-Os and sulfur isotopic systematics of sulfide ores indicate the contribution of not only mantle but likely crustal component in the evolution of sulfide melt. After separation from a primary mantle melt under subcrustal conditions, the silicate and sulfide melts evolved independently. Obtained data suggest that a local Ni, Cu, and PGE-rich mantle anomaly was formed through a plume–lithosphere interaction beneath the Kola–Norwegian Terrane (in its present-day outlines) of the Fennoscandian Shield at 2.75–1.9 Ga. This anomaly was a source of ore matter for three Early Precambrian copper–nickel ore epochs, in particular, for Neoarchean (~ 2750 Ma) deposits of the Allarechka ore field, Paleoproterozoic deposits (~ 2500 Ma) of the layered intrusions (e.g., Monchegorsk and Fedorova-Pana), and Pechenga group (~ 1900 Ma).

新太古代 U-Th-Pb (SHRIMP-II) 年龄为 2718 ± 7 Ma，用于位于 Fennoscandian 地盾的 Kola-Norwegian 地区的大型铜镍 Allarechka 矿床。该矿床与变质和深度侵蚀的火山-深成岩复合体有关，它们是新太古代绿岩带的年龄和地层类似物。Allarechka 矿区和 Annama 组寄主变质火山岩与 Ura Guba-Kolmozero-Voron'ya 绿岩带年龄相近的科马提岩-拉斑岩变质火山岩的组成相似，表明它们属于科马提岩-拉斑岩火山深成岩系列，其母体高铁科马提岩熔体是由耗尽的上地幔 ε _Nd (t) = +7.0 ± 0.4) 在高PT参数。矿石橄榄岩的岩相和地球化学成分表明，它们是由浅层（P ）中原生高铁科马提岩熔体中的Ol + Opx ± Pl, Mag分馏形成的堆积物。~ 4 kbar) 液相线温度至少为 1200°С 的岩浆室。微量元素和稀土元素地球化学、Nd 同位素组成以及副岩浆锆石的均质形态和同位素组成证明了中太古代 TTG 复合物对超重性陨石没有明显的地壳污染。相比之下，硫化物矿石的 Re-Os 和硫同位素系统表明不仅地幔而且可能的地壳成分对硫化物熔体的演化都有贡献。在地壳下条件下与原生地幔熔体分离后，硅酸盐和硫化物熔体独立演化。获得的数据表明，局部的 Ni、Cu、