Abstract

We studied the regularities of distribution of siderophile elements, including platinum group elements (PGE), in rock and in sulfides from Archean (2814 ± 51 Ma) peridotites collected in a fragment of deformed dike within the Bug granulite complex, Ukrainian Shield. In comparison with the primitive mantle, the studied rocks are enriched in Rh, Pd, Ni, Fe, and Co, and are characterized by low concentrations of other PGE. Sulfides are represented by a high-temperature variety of pentlandite and a small amount of chalcopyrite, with an inhomogeneous PGE distribution in them. Pd/Ir ratio typical of superchondrite is revealed for rocks and some sulfides. It is supposed that enrichment in Pd was not resulted from fractionation, but was rather related to mantle metasomatism. Saturation of the melt with sulfides and liquation process were favored by contamination of harzburgite with the host gneissic enderbite and fractionation of olivine. Solid sulfide solutions formed from sulfide melts at temperatures close to the crystallization temperature of magnesium phlogopite from a silicate melt.

中文翻译：

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硫化物中中高亲铁元素的分布作为重建乌克兰地盾 Bug 复合体太古代菱镁矿演化的基础

摘要

我们研究了包括铂族元素 (PGE) 在内的嗜铁元素在岩石和来自太古代 (2814 ± 51 Ma) 橄榄岩的硫化物中的分布规律，这些橄榄岩收集在乌克兰地盾 Bug 麻粒岩复合体内的变形岩脉碎片中。与原始地幔相比，所研究的岩石富含Rh、Pd、Ni、Fe和Co，并具有其他PGE含量低的特点。硫化物以高温变种的镍黄铁矿和少量黄铜矿为代表，其中 PGE 分布不均匀。岩石和一些硫化物揭示了典型的超球粒陨石 Pd/Ir 比率。推测 Pd 的富集不是由分馏作用引起的，而是与地幔交代作用有关。含硫化物的熔体饱和和液化过程有利于斜方辉石与主体片麻岩的尾矿咬合和橄榄石的分馏。由硫化物形成的固体硫化物溶液在接近镁金云母从硅酸盐熔体中结晶的温度下熔化。