Fractionation of platinum, palladium, nickel, and copper in sulfide–arsenide systems at magmatic temperature
Fractionation of platinum, palladium, nickel, and copper in sulfide–arsenide systems at magmatic temperature
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DOI：
10.1007/s00410-013-0951-9
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发表时间：
2013-11
影响因子：
3.5
通讯作者：
H. Helmy;C. Ballhaus;R. Fonseca;T. Nagel
中科院分区：
文献类型：
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作者：
H. Helmy;C. Ballhaus;R. Fonseca;T. Nagel
本文给出了硫化物熔体中砷化物相关系的实验结果，以定量地描述含砷硫化物熔体的分馏途径。当天然硫化物熔体达到砷化物饱和时，单独的富含Ni-PGE的砷化物熔体溶解。Fe-Ni-Cu硫化物熔体中的砷饱和浓度在0.5和1.5wt%之间。亲铜金属对不混溶的砷化物熔体的亲合力顺序为Pt > Pd > Ni> Fe> Cu。在自然系统中，砷化物的出溶是由溶解在硫化物熔体中的砷化镍成分的活性引发的，镍是最常见的贱金属，对Asn−阴离子物种有很强的亲和力。即使没有单独的砷化物相形成，砷也可能对硫化物熔体的分馏路径产生重大影响。砷，以及可能在岩浆熔体中的许多其他硫属元素和类金属，可能会经历与铂和钯的协会之前，离散铂族元素矿物成为稳定相。
Experimentally derived phase relations of arsenide in sulfide melt are presented to quantify the fractionation paths of As-bearing sulfide melts. When a natural sulfide melt reaches arsenide saturation, a separate Ni–PGE-rich arsenide melt exsolves. The arsenic saturation concentration in an Fe–Ni–Cu sulfide melt is between 0.5 and 1.5 wt%. The affinities of the chalcophile metals for an immiscible arsenide melt follow the order Pt > Pd > Ni ≫ Fe ≈ Cu. In natural systems, arsenide exsolution will be triggered by the activity of the nickel arsenide components dissolved in sulfide melt, Ni being the most common base metal with strong affinity to the Asn−anionic species. Arsenic may have a major effect on the fractionation paths of sulfide melts even if no separate arsenide phase forms. Arsenic, and probably many other chalcogens and metalloids in magmatic melts, may undergo associations with Pt and Pd well before discrete PGE minerals become stable phases.