极地研究

极地研究 ›› 2019, Vol. 31 ›› Issue (2): 168-178.DOI: 10.13679/j.jdyj.20180006

• 研究论文 • 上一篇    下一篇

GRV 13100：一块在南极新发现的顽火辉石球粒陨石

谢兰芳  陈宏毅  缪秉魁  夏志鹏  邵慧敏   

  1. 桂林理工大学, 广西隐伏金属矿产勘查重点实验室, 行星地质演化广西高校重点实验室, 桂林理工大学陨石与行星物质研究中心, 广西 桂林 541006
  • 收稿日期:2018-11-21 修回日期:2019-01-10 出版日期:2019-06-30 发布日期:2019-06-30
  • 通讯作者: 陈宏毅
  • 基金资助:

    国家自然科学基金项目(41866008, 41776196)、科技部国家科技基础条件平台项目(2005DKA 21406)、广西科技计划项目(桂科AD16450001)、广西隐伏金属矿产勘查重点实验室主任基金项目(13-A-01-02)资助

GRV 13100: A newly founded enstatite chondrite from Antarctica

Xie Lanfang, Chen Hongyi, Miao Bingkui, Xia Zhipeng, Shao Huimin   

  • Received:2018-11-21 Revised:2019-01-10 Online:2019-06-30 Published:2019-06-30
  • Contact: Hong-Yi CHEN

PDF (PC)

533

摘要：

球粒陨石为太阳系中最早形成的岩石, 包括普通球粒陨石、碳质球粒陨石、顽火辉石球粒陨石、R群和K群球粒陨石等, 其中顽火辉石球粒陨石在所有陨石中还原程度最高, 典型特征是含有大量铁镍镁锰钙等金属硫化物和(硅)磷化物等, 对其的研究可以为早期高度还原性太阳星云的演化过程提供约束。利用电子探针和激光拉曼等微区分析技术, 对新发现的南极陨石GRV 13100进行了详细的岩石学和矿物学研究工作。该陨石主要由不同类型的球粒、基质和不透明矿物组成, 球粒及基质矿物组成均以顽火辉石(En90.2—99.5Wo0.1—4.2)或辉石质玻璃(En85.0—88.8Wo0.1—4.1)为主, 次要矿物为钠长石(Ab91.0—98.3)、镁橄榄石(Fo98.7—99.9)、方石英和不透明矿物。不透明矿物包括铁纹石、陨硫铁、陨硫镁矿、陨硫铬铁矿、陨硫钙矿、陨磷铁矿和硅磷镍矿等。铁纹石中硅含量为2.23—3.90 wt.%, 陨硫镁铁锰矿固溶体以富含硫化镁为特征。根据球粒类型、结构、矿物组合和矿物成分, 特别是含有大量高度还原的金属硫化物等特征说明研究对象属于顽火辉石球粒陨石。而根据球粒大小、热变质程度和金属中硅含量等标准, 将其划分为EH4型, 冲击变质程度为S2, 风化程度为W2。

关键词: 顽火辉石球粒陨石, EH4型, 岩石学, 矿物学, 南极

Abstract:

Chondrites are stony meteorites that can be classified as enstatite chondrites, ordinary chondrites, car-bonaceous chondrites, K and R chondrite groups. Of these, enstatite chondrites are the most reduced. The evolution of highly reduced conditions of nebulae in the early solar system can be revealed by the metal-sulfide and metal-phosphide composition of enstatite chondrites. This study describes the petrology and mineralogy of a newly discovered meteorite, Grove Mountains (GRV) 13100, as determined using EPMA and Raman spectroscopy. The sample consists mainly of chondrules, matrix, and opaque minerals. The mineral composition of the chondrules and matrix are dominated by enstatite (En90.2–99.5 Wo0.1–4.2) and pyroxenitic glass (En85.0–88.8 Wo0.1–4.1); other components include a small amount of albite (Ab91.0–98.3), cristobalite, and forsterite (Fo98.7–99.9). Opaque minerals include kamacite, troilite, perryite, schreibersite, daubreelite, and niningerite. The content of silicon is 2.23–3.90 wt.%. The characteristic of niningerite is richer in MgS than FeS and MnS. According to the chondrule type, texture, mineral group and mineral composition, especially a large amount of highly reduced metal-sulfide, the sample belongs to enstatite chondrites. Based on our work, GRV 13100 is designated as a group EH enstatite chondrite, of thermal metamorphism grade 4, shock metamorphism stage S2, and weathering degree W2.

Key words: enstatite chondrite, EH4, petrology, mineralogy, Antarctica