【摘要】 峨眉山大火成岩省内带的攀西地区广泛分布着一系列赋存超大型钒钛磁铁矿矿床的镁铁-超镁铁质层状岩体，并局部伴生钴、镍的富集。本文以红格、攀枝花和太和三个大型钒钛磁铁矿成矿岩体为研究对象，通过系统分析铂族元素含量与全岩硫同位素组成，探讨高钛玄武质岩浆的硫化物饱和机制及其对伴生金属富集与深部PGE成矿潜力的制约。红格岩体∑PGE含量为0.3×10^-9～112.1×10^-9,Cu/Pd比值为2.1×10⁴～63×10⁴;攀枝花岩体ΣPGE含量为1.1×10^-9～19.4×10^-9,Cu/Pd比值为3.8×10⁴～99×10⁴;太和岩体∑PGE含量为0.6×10^-9～2.5×10^-9,Cu/Pd比值为29×10⁴～445×10⁴。全岩δ³⁴S值分别为+3.07±0.55‰、-0.03±0.39‰和+0.72±0.56‰，处于或略高于地幔值范围。这些地球化学特征表明，三大岩体的母岩浆在侵位浅部岩浆房之前，已在深部岩浆通道中经历了与早期熔离硫化物熔体之间的高R因子（硅酸盐岩浆与硫化物熔体的质量比）交换反应，导致PGE大量向硫化物熔体迁移并在其中富集，而非由结晶分异或显著地壳硫混染直接诱发的早期饱和。此类交换作用并未造成岩浆中Co、Ni的明显亏损。在岩浆侵入浅部岩浆房后，随着磁铁矿和钛铁矿的大量结晶，岩浆铁含量降低导致硫溶解度下降，继而引发有限而持续的硫化物饱和，在成矿岩体的中下部与钒钛磁铁矿矿层伴生富集，形成具有重要综合利用价值的钴、镍资源潜力。综合来看，高钛玄武质岩浆不仅具备形成超大型钒钛磁铁矿矿床的能力，还可能在深部孕育高品位少硫化物型PGE矿床。这一认识为未来在大型层状岩体周缘寻找PGE矿床及其伴生金属资源提供了新的思路与找矿方向。更多还原

【Abstract】 In the Panxi area of the inner zone of the Emeishan Large Igneous Province（ ELIP）,numerous mafic-ultramafic layered intrusions host giant Fe-Ti-V oxide deposits,locally accompanied by Co and Ni enrichment. This study focuses on three large Fe-Ti-V oxide-bearing intrusions（ Hongge,Panzhihua and Taihe） to investigate the sulfide saturation mechanism of high-Ti basaltic magmas and its control on associated metal enrichment and deep-seated PGE mineralization potential. Systematic analyses of platinum-group element（ PGE） abundances and whole-rock sulfur isotopes show that ∑PGE contents are 0. 3 × 10^-9～ 112 × 10^-9with Cu/Pd ratios of 2. 1 × 10⁴～ 63 × 10⁴ for Hongge,1. 1 × 10^-9～ 19. 4 × 10^-9and 3. 8 × 10⁴～ 99 × 10⁴ for Panzhihua,and 0. 6 × 10^-9～ 2. 5 × 10^-9and29 × 10⁴～ 445 × 10⁴ for Taihe. Whole-rock δ³⁴S values are + 3. 07 ± 0. 55‰,-0. 03 ± 0. 39‰,and + 0. 72 ± 0. 56‰,respectively,within or slightly above the mantle range. These geochemical characteristics indicate that,prior to emplacement into shallow-level magma chambers,the parental magmas underwent high-R-factor（ mass ratio of silicate melt against sulfide melt） exchange reactions with early segregated sulfide melts in deep magma conduits,resulting in substantial transfer and enrichment of PGEs into the sulfide melts. This process,rather than fractional crystallization or significant crustal sulfur assimilation,was the primary driver of early PGE depletion. Importantly,such exchange did not cause marked depletion of Co and Ni in the magmas. Upon intrusion into shallow chambers,extensive crystallization of magnetite and ilmenite lowered the Fe content of the magma,reducing sulfur solubility and triggering limited but sustained sulfide saturation. This led to localized enrichment of Co-and Ni-bearing sulfides in the middle to lower parts of the intrusions,spatially associated with Fe-Ti-V oxide layers. Overall,high-Ti basaltic magmas in the ELIP not only have the capacity to form giant Fe-Ti-V oxide deposits,but also possess the potential to generate high-grade,sulfide-poor PGE deposits at depth. These findings provide new insights and exploration strategies for PGE and associated metal resources in the vicinity of large layered intrusions.更多还原