南极格罗夫山H群普通球粒陨石冲击变质特征  

SHOCK METAMORPHISM OF H-CHONDRITES FROM THE GROVE MOUNTAINS,ANTARCTICA

作　　者：王江[1,2] 缪秉魁[1,2] 张健[1,2] 

机构地区：[1]桂林理工大学地球科学学院,桂林541004 [2]桂林理工大学广西地质工程中心区重点实验室,桂林541004

出　　处：《极地研究》2010年第3期231-243,共13页Chinese Journal of Polar Research

基　　金：中国科学院知识创新重要方向项目(kzcx2-yw-110-4);国家自然科学基金项目(40673055)资助

摘　　要：本文研究了47块南极格罗夫山H群普通球粒陨石冲击变质效应。在光学显微镜下对陨石中硅酸盐矿物和不透明矿物的冲击变质效应,其中包括波状消光、破裂、马赛克消光、冲击熔融和金属硫化物枝状共晶,进行了观察。利用扫描电镜对10块H群普通球粒陨石的不透明冲击熔脉进行观察与分析,在GRV022469冲击熔脉中发现了瓦茨利石。GRV022469成为我国第一块发现高压相矿物的南极H群普通球粒陨石。瓦茨利石的岩石矿物学特征表明它形成于固态相变机制。根据冲击变质效应,特别是冲击熔脉中矿物结构及成分,分析得出H群普通球粒陨石的冲击变质特征:H群普通球粒陨石冲击变质程度普遍偏低(低于S5),陨石中冲击熔脉宽度较窄,脉体中矿物组合为常压相矿物。Shock metamorphism of 47H-Chondrites from Grove Mountains（GRV）,Antarctica,were studied.Silicate and opaque minerals were observed under optical microscope for shock metamorphism features,such as undulatory extinction,planar fractures,mosaic extinction,shock-induced melting,and metal-sulfide dendritic eutectic.Shock-induced regions of 10H-Chondrites were observed.Wadsleyite was found in GRV022469.Petrologic and mineralogical characteristics support that Wadsleyite was formed by solid-state transformation.Based on shock effects,especially low-pressure phase mineral components and chemical characteristic,shock metamorphism stage of H-Chondrites is relatively low （lower than the S5）.Shock-induced melt veins are thinner compared to those in L-Chondrites.

关 键 词：南极 格罗夫山 H群普通球粒陨石 冲击变质 瓦茨利石 冲击历史 

分 类 号：P185.83[天文地球—天文学]