Abstract:

A detailed petrographical and mineralogical study is conducted on 100 Grove Mountains(GRV) meteorites.There are four rear types of meteorites including 1 CM2 chondrite(GRV 050179),1 mesosiderite(GRV 050212),1 eucrite(GRV 051523) and 1 ureilite(GRV 052382).GRV 050179 consists of predominant phyllosilicates and poor characterized phases,suggesting strong aqueous alteration and typical of CM2 chondrites.The coarse-grained olivine of GRV 052382 is heavily shocked,recystallized into small euhedral crystals.Diamond(1—3μm) is found in carbonrich assemblages.This meteorite is classified as an ureilite.GRV 050212 contains 12.3 vol% of igneous textures.FeO/MnO weight ratios of low-Ca pyroxenes in both GRV 050212(30.0) and GRV 051523(28.7—30.9) are within the range of HED(Howardites-Eucrites-Diogenites) clan.Of 93 ordinary chondrites,there are 5 unequilibrated ordinary chondrites(GRV 050165,GRV 050189,GRV 050200,GRV 050404 and GRV 053167).According to PMD of fayalite content of olivine,the subtypes of these unequilibrated ordinary chondrites are 3.5,3.4,3.4,3.4 and 3.5,respectively.Other 88 equilibrated ordinary chondrites are classified into H(34) and L(54) groups without LL chondrites.The Grove Mountains meteorites have more L and less H chondrites than other Antarctica meteorite recovered by US.Other 3 small fragments of the meteorites mainly consist of metal with minor silicates.Co content of kamacite and fayalite content of olivine of these fragments are within the ranges of H and L-groups.These metal-rich fragments may be large metal grains from ordinary chondrites.Terrestrial weathering of most ordinary chondrites is weak(W1 for 22 of them) or moderate(W2 for 61 ordinary chondrites),and only 10 ordinary chondrites are severely weathered(W3).