关键词: 南极;格罗夫山;普通球粒陨石;岩石矿物学;撞击熔融

Abstract:

An ordinary chondrite(Sample No.GRV052483) was recovered on blue ice during the 22nd Chinese Antarctic Research Exploration in Grove Mountains,Antarctica.In thin section,the sample shows a recrystallization texture and the texture is not particularly chondritic.Most euhedral to subhedral olivine crystals are set in a mesostasis of fine-grained olivine,pyroxene,and tiny spheres of Ni,Fe-rich metal and sulfides.Most olivine grains are essentially relicts.The major silicate phases are olivine,orthopyroxene,and plagioclase,with trace clinopyroxene.The mean Fa of olivine crystals and matrix are 24.7 mol%,and the mean Fs of low-Ca pyroxene is 21.1 mol% in GRV052483.These values are in the L chondrite range.Metal and sulfides are Fe–Ni metal(kamacite,taenite) and troilite.Minor phases are chromite and apatite.Abundant dark portions,numerous cracks and microfaults,as well as impact-melt veins,are also present.As a result,GRV052483 is an L6-chondrite impact-melt rock(i.e.,shocked L-6 chondrite).