Abstract

Intrusions of the Zubovsky type (1) are commonly dominated by troctolite in their ultramafic parts and have an insignificant number (if any) of ultramafic units; (2) occur among olivine and olivine-bearing gabbro-dolerites and often show evidence of a number of accumulation of cumulus olivine, (3) have weakly pronounced (if any) taxitic gabbrodolerite units; (4) include widespread leucocratic hybrid-metasomatic rocks and hybrid quartz- and cordierite-bearing norites and gabbronorites at contacts with the host aluminosilicate rocks; and (5) generally have a low ore content, with the prevalence of disseminated ore units among troctolites and ultramafic rocks, and almost complete absence of massive sulfide ores. The paper is the first to present data on the composition and Nd–Sr–Cu–S isotope-geochemical characteristics of rocks and sulfide ores from the Zubovsky-type intrusions in the Norilsk area. The silicate material of the Zub-Marksheider and Vologochan intrusions is characterized by similar Nd–Sr isotopic parameters: ε_Nd = –1.2 ± 0.5, (⁸⁷Sr/⁸⁶Sr_i) = 0.70685 ± 0.00127, and ε_Nd = 1.2 ± 0.8, (⁸⁷Sr/⁸⁶Sr_i) = 0.70634 ± 0.00068, respectively. These parameters are close to those of intrusions accompanied by economic ore mineralization in the Norilsk area. The whole-rock samples generally have a more ‘radiogenic’ Nd isotopic composition than that of the pyroxene and plagioclase and less ‘radiogenic’ than that of the olivine. The highest ε_Nd value (ca. 5.3) of the olivine indicates that depleted mantle (DM) material was involved in the magma-generating processes. Copper–sulfur isotope data for sulfide ores of the Zub-Marksheider and Vologochan intrusions are remarkably different: δ³⁴S = 1.3 ± 2.3‰, δ⁶⁵Cu = –0.1 ± 0.15‰ and δ³⁴S = 7.0 ± 1.2‰, δ⁶⁵Cu = –0.7 ± 0.3‰, respectively. The Cu isotope composition of the sulfide mineralization of both intrusions is close to that of massive and disseminated sulfide ores from the Talnakh deposit in the Norilsk area. The sulfur isotope data suggest that the host rocks had little effect on sulfide mineralization. The identified Nd–Sr–S–Cu isotope-geochemical parameters of the rocks and ores are an important indicator of the potential for rich PGE–Cu–Ni sulfide ores.

中文翻译：

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诺里尔斯克地区Zubovsky类型的基性-超镁铁质侵入体：岩石化学，地球化学和矿石潜力

摘要

Zubovsky类型的侵入体（1）通常在其超镁铁质部分中由滑石矿为主，并且具有微不足道的数量（如果有）。（2）发生在橄榄石和含橄榄石的辉长岩-长石中，并且经常显示出大量的积聚橄榄石积聚的证据，（3）具有明显的（如果有的话）滑石辉长辉石单位；（4）包括与主体铝硅酸盐岩接触的广泛的白垩统杂交代岩石，杂化含石英和堇青石的辉石和辉长岩；（5）矿石含量通常较低，三方沸石和超镁铁岩中散布的矿石单元普遍存在，几乎没有块状硫化物矿石。该论文是第一份介绍诺里尔斯克地区Zubovsky型侵入岩的岩石和硫化矿石的组成和Nd-Sr-Cu-S同位素地球化学特征的数据。Zub-Marksheider和Vologochan侵入体的硅酸盐材料具有类似的Nd-Sr同位素参数：ε_ND = -1.2±0.5（⁸⁷ SR / ⁸⁶锶_我）= 0.70685±0.00127，和ε_的Nd = 1.2±0.8，（⁸⁷ SR / ⁸⁶锶_我分别）= 0.70634±0.00068，。这些参数与诺里尔斯克地区伴有经济矿石矿化的侵入岩相近。整个岩石样品的Nd同位素组成通常比辉石和斜长岩具有更高的“放射成因”，而橄榄石的“放射成因”则更少。最高_εNd橄榄石的值（约5.3）表明耗尽的地幔（DM）物质参与了岩浆的生成过程。用于ZUB-Marksheider和Vologochan入侵的硫化物矿石铜硫同位素数据是显着不同的：δ ³⁴ S = 1.3±2.3‰，δ ⁶⁵的Cu = -0.1±0.15‰和δ ³⁴ S = 7.0±1.2‰，δ ⁶⁵Cu分别为–0.7±0.3‰。两次侵入的硫化物矿化的Cu同位素组成都与Norilsk地区Talnakh矿床中块状且散布的硫化物矿石接近。硫同位素数据表明，基质岩对硫化物矿化的影响很小。岩石和矿石中已确定的Nd-Sr-S-Cu同位素地球化学参数是富含PGE-Cu-Ni硫化物矿石潜力的重要指标。