非岩浆型铁陨石形成时间和演化过程的Re-Os同位素研究

相对于被广泛研究的岩浆型铁陨石，非岩浆型铁陨石的成因和形成过程仍不清楚并存在很大争议。本项目拟通过对非岩浆型铁陨石内的主体金属相及其内部其它主要组分，如陨硫铁、陨磷铁镍石、硅酸盐包体等，应用负离子热电离质谱（NTIMS）开展Re-Os同位素组成的高精度分析，以期获得IAB/IIICD和IIE群非岩浆型铁陨石的结晶年龄；以及计算单个陨石中陨硫铁、陨磷铁镍石和硅酸盐包体的内部等时线；并对主体金属相部分使用ICP-MS进行微量元素测定，确定非岩浆型铁陨石微量元素的分布模式。从而了解非岩浆型铁陨石群之间、及样品中金属与硫化物及硅酸盐相的结晶分异时间和成因关系，进而探讨非岩浆型铁陨石的成因并建立其演化模式。此项研究对理解太阳系早期的演化过程将有重要启示。

Compared with magmatic iron meteorites which have been researched in detail on their origin and evolution, it is still unclear and controversial for origin of nonmagmatic iron meteorites. This project intends to study the nonmagmatic iron meteorites which include IAB/IIICD and IIE group. We will analyze Re-Os isotopic compositions of the major components in the nonmagmatic iron meteorites, using negative thermal ionization mass spectrometry (NTIMS). The components in the iron meteorites include FeNi metals (major phase), and inclusions (e.g., troilites, schreibersites, silicate). And we will also measure the trace elements of metal sections using ICP-MS. The Re-Os system data can be used to determine crystallization ages of IAB/ IIICD and IIE group, as well as interior isochrone ages of the minerals. The trace elements data will display the distrubution patterns of the nonmagmatic iron meteorites. All above research results will help us to understand the differentiation time and genetic relationships among nonmagmatic iron groups and different components in a meteorite sample. The study will result in better understnd on the evolution processes of the early solar system.