极地研究

极地研究 ›› 2014, Vol. 26 ›› Issue (3): 369-377.DOI: 10.13679/j.jdyj.2014.2.369

• 研究论文 • 上一篇    下一篇

南极GRV 022888和GRV 052408橄辉无球粒陨石的岩石矿物学特征及成因探讨

黄婉1,2  何琦1  肖龙1   

  1. 1中国地质大学（武汉）行星科学研究所， 湖北 武汉 430074；
    2湖北省鄂东南地质大队,湖北 大冶 435100
  • 收稿日期:2012-12-17 修回日期:2013-06-27 出版日期:2014-09-30 发布日期:2014-09-30
  • 通讯作者: 肖龙
  • 基金资助:

    自然科学基金项目

PETROLOGY, MINERALOGY AND PETROGENESIS OF GROVE MOUNTAINS(GRV)022888 AND 052408 UREILITES FROM ANTARCTICA

HUANG Wan1,2, HE Qi1, XIAO Long1   

  1.  
    1Plantary Science Institute, China University of Geoscience, Wuhan 430074, China；
    2Geological Brigade of Southeastern Hubei，Daye 435100, China
  • Received:2012-12-17 Revised:2013-06-27 Online:2014-09-30 Published:2014-09-30

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摘要： 本文主要介绍GRV 022888和GRV 052408两块南极陨石的岩相学和矿物化学特征，并在此基础上探讨其成因。GRV 052408陨石主要由橄榄石（~60 vol%）和辉石（~35 vol%）组成，含少量富碳质填隙物（~5 vol%）；而GRV 022888陨石基本由橄榄石（~98 vol%）构成，仅有很少量辉石，富碳质不透明填隙物含量也较低（~2 vol%）。这两块陨石中的橄榄石都可以见到明显的核部富铁边部富镁的反环带结构。结合岩相学和矿物化学特征，将它们划分为单矿Ⅰ型橄辉无球粒陨石。根据橄榄石-易变辉石-熔体温度计，计算得到两块陨石的形成温度在1 220℃左右。我们的研究结果支持橄辉无球粒陨石为球粒陨石质母体部分熔融后的残余物成因假说。

关键词: 南极陨石, 橄辉无球粒陨石, 还原结构, 成因

Abstract: Here we report on the petrology and mineralogy of GRV 022888 and GRV 052408 ureilites recovered from the Grove Mountains in Antarctica. Based on the petrologic and mineralogical characteristics, we provide new insight into the origin and evolution of ureilites. The mineral assemblages in GRV 022888 were mainly olivine (~98%), with a few pyroxene and carbonaceous opaque interstitial assemblages (~2%). The GRV 052408 ureilite was composed mainly of olivine (~60%), pyroxene (~35%), and carbonaceous opaque interstitial (~5%) mineral assemblages. The olivines in both meteorites had a distinctly reverse-zoned structure, and the cores had a high Fe content while the rims had a high Mg content. The petrologic characteristics classified both as type-I monomict ureilites. The formation temperature calculated using an olivine-pigeonite-liquid geothermometer was high, at about 1220°C. Our findings suggest that the magma of these ureilites is the partially melted residue of a ureilite parent body, similar to material involved in the formation of chondrites.

Key words: Antarctic meteorite, ureilite, reverse zoning, origin