富钙长石-橄榄石包体与其他部分典型包体W-L边的成因

发布时间：2018-03-08 14:08

本文选题：W-L边　切入点：矿物岩石学特征　出处：《岩石学报》2016年01期 　论文类型：期刊论文

【摘要】：球粒陨石中的富Ca、Al包体(简称CAI)形成于星云演化的最初始阶段,保存了大量星云形成和演化的各种信息。研究认为,包体的成因主要包括星云直接凝聚和熔融结晶,少部分甚至经历过高温蒸发过程。部分CAI最外层具有由一种或几种矿物组成的Warking-Lovering边(简称为W-L边),CAI和其W-L边对于认识早期星云环境和界定CAI的形成时间等均具有重要意义。目前,对于W-L边的形成过程研究并不深入,且一直存在争议。本文主要介绍了三个典型包体:C#1(富钙长石-橄榄石包体)、GRV 022459-2RI5(A型包体)和GRV 021579-3RI5(富尖晶石球粒状包体)及其W-L边的矿物岩石学和氧同位素组成特征。C#1包体明显经历过熔融结晶过程,W-L边氧同位素组成具有与包体内部矿物相似的富~(16)O同位素特征,表明W-L边的成因与包体的形成过程密切相关,形成于同一富~(16)O同位素组成区域,且W-L边属于包体熔融结晶过程后期的产物。矿物岩石学特征表明,GRV 022459-2RI5属于星云直接凝聚形成,其W-L边为包体形成过程最晚期星云凝聚产物。GRV021579-3RI5经历过熔融结晶过程,其W-L边为包体结晶最后阶段的产物。
[Abstract]:The Ca-rich inclusion (CAII) in chondrites formed in the initial stage of nebula evolution and preserved a great deal of information of nebula formation and evolution. It is considered that the genesis of inclusion mainly includes the direct condensation and melting crystallization of nebula. A few have even experienced high temperature evaporation. Some CAI have a Warking-Lovering edge (W-L edge for short) consisting of one or more minerals and its W-L edge for understanding the environment of the early nebula and defining the forming time of CAI. Important. Right now, The formation process of W-L edge is not deeply studied. This paper mainly introduces three typical inclusions: C #1 (Calcium-rich feldspar olivine inclusions) and GRV 021579-3RI5 (spinel spherulite inclusions) and their mineralogical petrology and oxygen isotopic compositions along the W-L boundary. The oxygen isotopic composition of the W-L borderline of the C#1 enclave has the characteristics of rich O16 O isotopes similar to the minerals in the inclusions. It is shown that the origin of W-L edge is closely related to the formation process of inclusion, and formed in the same isotopic region rich in 16O, and the W-L edge belongs to the product of the late melting crystallization process of inclusion. The mineralogical and petrological characteristics indicate that GRV 022459-2RI5 belongs to the direct condensation of nebula. The W-L edge is the product of nebula condensation in the most late stage of inclusion formation. GRV021579-3RI5 has gone through the melting crystallization process, and its W-L edge is the product of the final stage of inclusion crystallization.
【作者单位】：湖南科技大学地质研究所;页岩气资源利用湖南省重点实验室;中国科学院地质与地球物理研究所;
【基金】：国家自然科学基金项目(41103032) 湖南省教育厅优秀青年项目(15B080) 环境地球化学国家重点实验室开放基金(SKLE1423)联合资助
【分类号】：P185.83

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