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

碳质和普通球粒陨石物理分离成分中的高度亲铁元素和铬同位素变化

• 批准号: 211587748
• 负责人: Professor Dr. Harry Becker
• 金额: --
• 依托单位: Institut für Geologische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/211587748?language=en
• 关键词: Highly; siderophile; element; chromium; isotopic

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.

在不同种类的原始陨石（球粒陨石）中，金属成分的富集和耗尽的过程仍然很少受到限制。此外，球粒陨石中亲铁元素丰度变化的原因尚不完全清楚。通过与亲石元素的比较，我们知道球粒陨石中中等挥发性的高亲铁元素（HSE）至少部分受到挥发性元素耗尽或添加的影响。令人惊讶的是，与碳质球粒陨石相比，难熔的高亲铁元素在普通球粒陨石和顽辉石球粒陨石中也显示出系统差异。早期太阳星云中的部分凝结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块状球粒陨石中观察到的HSE丰度的额外控制因素的作用仍有待全面评估。本文拟研究不同组球粒陨石分离组分在同一溶出物中的锇同位素组成、HSE丰度以及Fe/Ni、Fe/S、Fe/Mg等主要元素比值。这些数据也将有助于我们了解球粒陨石成分如球粒和基质的形成和修饰过程。