南极格罗夫山陨石GRV 020043—一个特殊的E/H过渡型球粒陨石

GRV 020043-A Special Transition Chondrite Between E and H Group

南极格罗夫山陨石GRV0 20043是一块特殊的球粒陨石,虽与普通球粒陨石有着相似的矿物组合,但矿物成分超出普通球粒陨石范围。主要矿物组合及其模式含量(vol%)是:斜方辉石40、橄榄石24、透辉石8、斜长石10、Fe-Ni合金14、陨硫铁4vol%、及少量铬铁矿和磷灰石。主要组成矿物成分均一,如斜方辉石(Fs10.1～11.6,平均Fs10.9)、橄榄石(Fa10.4-12.4,平均Fa11.0)、透辉石(Wo46.1-47.1En49.0-49.6Fs3.8-4.4,平均Wo46.6En49.3Fs4.0)、斜长石(Ab55.7-72.5Or2.1-5.0An24.0-42.1,平均Ab67.6Or3.4An29.0)等。该陨石球粒轮廓清晰结构完整,球粒丰度37%(体积比),基质具有中等重结晶,岩石类型属于4型。根据矿物成分判断,GRV0 20043陨石的氧化程度和橄榄石含量介于E群和H群之间,故将该陨石划分为E/H过渡型球粒陨石。

Grove Mountains （GRV） 020043 is a special chondrite,which has the same mineral assemblage as ordinary chondrite,but it has its own mineral compositions beyond those of the ordinary chondrites. The stone is composed of Low-Ca pyroxene（40 vol%）,olivine（24vol%）,diopside（8 vol%）,plagioclase（10vol%）,troilite（4 vol%）,Fe-Ni alloy （14 vol%）,and trace of chromite and apatite. The silicates have homogeneous compositions,e.g. olivine （Fa10.4-12.4,average Fa11.0） and Low-Ca pyroxene （Fs10.1-11.6,average Fs10.9）,diopside （Wo46.1-47.1En49.0-49.2Fs3.8-4.4,average Wo46.6En49.3Fs4.0）,plgioclase （Ab55.7-72.5Or2.1-5.0An24.0-42.1,average Ab67.6Or3.4An29.0）. Some chondrules in this meteorite are well defined with sharp edges,with the chondrules aboundence of 37 vol%. The matrix of the meteorite is moderately recrystallized. Its petrologic type is 4. Based on its mineral compositions,olivine model abundance and oxidation intensity of GRV 020043 are restricted between E and H groups. The chondrite is classified classed as a transition chondrite between E and H group.