福建紫金山斑岩体系成矿过程与铜金成矿潜力：铂族元素和矿物原位硫、氧、铁同位素示踪

Saturation of the magma with sulfide facilitates the concentration of metals into smaller volumes of material from which they can later be released; efficient focusing of flow through a narrow window and the physicochemical conditions could force sulfide mineral precipitation in a limited rock volume, creating rich mineralization in porphyry system. In this proposal, sulfide saturation of ore-related intrusions from the Zijinshan porphyry systems in South China would be identified by analyzing the PGE contents, in order to reveal the process on stripping of siderophile and chalcophile metals into a sulfide-melt phase and producing a highly enriched anomaly and a depleted silicate melt. And then Cu- and/or Au-bearing and barren felsic systems can be distinguished and Cu and Au fertility will be determined. In addition, the physicochemical conditions, the metal source, and the evolution of the fluid evolution processes including phase separation and mixing will be studied by mineral cathodoluminescence image and SIMS in-situ S–O–Fe isotope compositions. The model of these typical porphyry Cu-Au-Mo systems can be built based on the comprehensive analysis their ore genesis. This will not only provide new evidence for the metallogenic theory of epithermal deposits and the geodynamic mechanism but also is beneficial to further ore prospecting significantly.

斑岩体系中岩浆的硫饱和过程控制着金属的预富集和释放，成矿流体物理化学条件的变化影响着成矿物质的迁移与沉淀。本项目通过对福建紫金山斑岩成矿体系含矿斑岩的铂族元素分析，查明岩浆的硫饱和过程，揭示岩浆演化过程中金属元素从岩浆体系中分离及富集机制，进而区分含铜或金的斑岩体，识别无矿岩体，判定铜金的成矿潜力；通过矿物的阴极发光图像、离子探针硫、氧、铁同位素分析，查明成矿流体演化过程中的物理化学参数及流体来源、相分离和混合机制，精细刻画流体成矿过程。综合研究矿床成因，建立紫金山斑岩矿床成矿模型，指示地球动力学背景并服务于找矿勘探。

斑岩体系中岩浆的硫饱和过程控制着金属的预富集和释放，成矿流体物理化学条件的变化影响着成矿物质的迁移与沉淀。本项目通过对福建紫金山斑岩成矿体系含矿斑岩的微量（包括铂族）元素分析，查明岩浆的硫饱和过程发生在岩浆演化的早期，大部分铜金成矿元素聚集于地壳下部，幕式部分熔融和流体活化作用可能是控制金属元素富集的关键。查明紫金山斑岩-浅成低温热液铜金钼矿集区成矿流体主要源于地幔起源的岩浆，表生氧化过程控制金的富集；铜成矿带为原生成因，勘探潜力大。利用Fe-S同位素体系可有效区分斑岩矿床与其他类型的热液矿床。综合研究矿床成因，建立紫金山斑岩矿床成矿模型，指示地球动力学背景并服务于找矿勘探。