The composition of the parental magmas of Cu–Ni deposits is crucial for the elucidation of their genesis. In order to estimate the role of magma in ore formation, it is necessary to compare the compositions of silicate rock intrusions with different mineralization patterns, as observed in the Norilsk region. The rock geochemistry of two massifs located in the same Devonian carbonate rocks—the Kharaelakh intrusion, with its world-class platinum-group element (PGE)–Cu–Ni deposit, and the Pyasinsky–Vologochansky intrusion, with its large deposit—was studied. Along with these massifs, the Norilsk 2 massif with noneconomic mineralization intruded in the Ivakinskaya–Nadezhdinskaya basalts was studied as well. Their settings allow the estimation of the parental magma composition, taking into account the possible assimilation of host rocks. Analyses of 39 elements in 97 samples demonstrated the similarity of the intrusions in terms of their major components. The Pyasinsky–Vologochansky intrusion contains the highest trace element contents compared with the Kharaelakh and Norilsk 2 massifs, evidencing its crystallization from evolved parental magma. No influence of host rocks on the silicate rock compositions was found, except for narrow (1–2 m) endo-contact zones. There is no correlation between the mineralization volume and the rock compositions of the studied intrusions. It is assumed that the intrusions were formed from one magma crustal source irregularly rich in sulfur (S). This source inhomogeneity in terms of the sulfur distribution resulted in deposits of varying sizes. The magmas served as a transporting agent for sulfides from deep zones to the surface.

中文翻译：

---

诺里尔斯克地区含矿侵入体化学特征及PGE-Cu-Ni成矿成因

铜镍矿床母岩浆的组成对于阐明其成因至关重要。为了估计岩浆在矿石形成中的作用，有必要比较在诺里尔斯克地区观察到的具有不同矿化模式的硅酸盐岩侵入体的成分。研究了位于同一泥盆纪碳酸盐岩中的两个地块——拥有世界一流铂族元素 (PGE)-Cu-Ni 矿床的 Kharaelakh 侵入体和拥有大量矿床的 Pyasinsky-Vologochansky 侵入体的岩石地球化学. 除了这些地块，还研究了侵入 Ivakinskaya-Nadezhdinskaya 玄武岩的具有非经济矿化作用的 Norilsk 2 地块。他们的设置允许估计母岩浆成分，同时考虑到可能的母岩同化。对 97 个样品中的 39 个元素的分析证明了入侵的主要成分的相似性。与 Kharaelakh 和 Norilsk 2 地块相比，Pyasinsky-Vologochansky 侵入体含有最高的微量元素含量，证明其从演化的母岩浆中结晶。除了狭窄的 (1-2 m) 内接触带外，没有发现主岩对硅酸盐岩石成分的影响。矿化体积与所研究侵入体的岩石成分之间没有相关性。假设侵入体是由一个不规则富含硫 (S) 的岩浆地壳源形成的。这种源在硫分布方面的不均匀性导致了不同大小的沉积物。岩浆作为硫化物从深部到地表的运输剂。