Highly siderophile element and chromium isotopic variations in physically separated components of carbonaceous and ordinary chondrites

对各种原始陨石(球粒陨石)中的金属成分进行浓缩和贫化的过程仍然受到很差的约束。此外，球粒陨石中亲铁(爱铁)元素丰度变化的原因还不完全清楚。通过与亲石元素的比较，已知球粒陨石中中等挥发性的高度亲铁元素(HSE)至少部分受挥发性元素的枯竭或添加的影响。令人惊讶的是，与碳质球粒陨石相比，普通球粒陨石和顽火辉石球粒陨石中难熔的高度亲铁元素也显示出系统的差异。早期太阳星云中的部分凝聚被认为是一种可能的解释。固体金属-液态金属、金属-硅酸盐或硫化物硅酸盐分配作为在块状球粒陨石中观察到的HSE丰度的额外控制作用仍有待全面评估。本文研究了不同组分球粒陨石同一消解液中的Os同位素组成、HSe丰度和Fe/Ni、Fe/S、Fe/Mg等常量元素比值。这些数据还有助于我们了解球粒陨石成分的形成和变质过程，如球粒陨石和基质。

The processes that have enriched and depleted the metal component in various groups of primitive meteorites (chondrites) are still poorly constrained. In addition, the causes of abundance variations of siderophile (iron loving) elements in chondrites are incompletely understood. From comparisons with lithophile elements, it has been known that moderately volatile highly siderophile elements (HSE) in chondrites are at least partly affected by volatile element depletion or addition. Surprisingly, refractory highly siderophile elements also display systematic differences in ordinary and enstatite chondrites compared to carbonaceous chondrites. Fractional condensation in the early solar nebula has been suggested as one possible explanation. The role of solid metal-liquid metal, metal-silicate or sulphide silicate partitioning as additional controls of HSE abundances observed in bulk chondrites remains to be evaluated in a comprehensive way. Here it is proposed to study osmium isotopic compositions, HSE abundances, and major element ratios such as Fe/Ni, Fe/S and Fe/Mg in the same digestion aliquot of separated components of chondrites from different groups. Such data will also facilitate our understanding of the formation and modification processes of chondrite components such as chondrules and matrix.