Fluid-inclusion data for vein-type Cu-Ni-PGE footwall ores, Sudbury Igneous Complex and their use in establishing an exploration model for hydrothermal PGE-enrichment around mafic-ultramafic intrusions
Fluid-inclusion data for vein-type Cu-Ni-PGE footwall ores, Sudbury Igneous Complex and their use in establishing an exploration model for hydrothermal PGE-enrichment around mafic-ultramafic intrusions
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萨德伯里火成岩杂岩脉型 Cu-Ni-PGE 下盘矿的流体包裹体数据及其在建立镁铁质-超镁质岩体周围热液 PGE 富集勘探模型中的应用
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
D. H. Watkinson
中科院分区：
文献类型：
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作者：
F. Molnár;D. H. Watkinson
在苏德伯里火成岩杂岩北段的McCreedy East和Whistle矿区，以及南段的Lindsley和Little Stobie矿区研究了铜镍pge下盘矿床。这些地区下盘矿石不同于萨德伯里矿区典型的岩浆型Fe-Ni-Cu-PGE矿床，具有较高的Cu/Ni比和较高的PGE含量，呈脉状，矿石与含水硅酸盐的结合普遍存在。对比流体包裹体岩石学和下盘矿石显微测温结果表明，高温（300℃~ 480℃）和富重金属盐（高达约40 NaCl当量wt%盐度）流体与中高压（约2 kbar）下富pge矿石的形成有关。然而，在不同的地方也发现了几个可能独立的流体循环阶段，成矿流体的详细特征也存在差异，特别是比较北、南山脉的数据。因此，除了流体的高温和高盐度外，热液过程的性质也存在局部变化。这些差异可能与流体（岩浆、变质和地层盐水）的不同来源以及它们与组成不同的下盘岩性相互作用的不同程度有关。
Cu-Ni-PGE footwall ore deposits were studied in the McCreedy East and Whistle mines along the North Range, and the Lindsley and Little Stobie mines along the South Range of the Sudbury Igneous Complex. The footwall ores in these localities differ from typical magmatic Fe-Ni-Cu-PGE deposits in the Sudbury mining camp: they have higher Cu/Ni ratios, higher PGE content, vein-like appearance and ubiquitous association of ore with hydrous silicates. Results of comparative fluid inclusion petrography and microthermometry of footwall ores indicate that high temperatures (300°C to 480°C) and heavy-metal rich saline (up to about 40 NaCl equivalent wt% salinity) fluids were associated with the formation of the PGE-rich footwall ores at moderately high pressures (around 2 kbars). However, several, possibly independent fluid circulation stages were also found at the different localities and there also are differences in detailed characteristics for ore-forming fluids especially comparing data from the North Range and the South Range. Thus, in addition to the high temperature and salinity of fluids, there are local variations in the nature of hydrothermal processes. These differences may be related to the diverse origin of fluids (magmatic, metamorphic, and formational brines) and their differing extents of interaction with the compositionally different footwall lithologies.