Petrological studies on the HED meteorites and their parent bodies

陨石标本1152是一块不含角砾石的全晶非球粒陨石，具有相当独特的结构。该标本的岩性与已知的所有无球粒陨石有很大的不同，但其化学成分和矿物组合可能属于无球粒陨石族。该样品与大多数辉石的矿物组合一致，主要由辉石(En47.4-82.5 Fs17.4-34.8 Wo0.9-35.2)和斜长石(Ab5.8-10.4 An89.2-94.2 Or0.0-0.3)和少量橄榄石(Fo58.6-63.0 Fa37.0-41.4)组成。这也是与钠镁石几乎相同的块体化学成分，例如典型的钠镁石Yamato-791157多金属角砾岩。标本相当独特的结构可能表明该样品含有钠镁石成分。然而，作者预计，该陨石标本是第一个由HED(Howardite-Eucite-Diogite)母体可能的小行星4 Vesta上的岩浆作用形成的无角砾石-全晶结构的陨石。样品1152陨石的整体化学成分为49.50SiO_2，0.09TiO_2，7.34Al203，6.28Fe_2O_3，9.73FeO，0.37MnO，19.02Mg0，5.58CaO，0.19Na_2O，&lt；0.02K20，0.1H_2O(+)，0.10H_2O(-)，0.21P_2O_5，0.52Cr_2O_3，1.42FeS，&lt；0.1Fe，总重量百分比(%)为100.57。

The meteorite specimen 1152 is an unbrecciated-holocrystalline achondrite showing quite unique texture. The lithology of this specimen is quite differ from all known achondrite meteorites, however it might be classified to one of howardite group for its chemical compositions and mineral assemblages. The specimen is as same as mineral assemblage of the most howardites, and it consists mainly of pyroxene(En47.4-82.5 Fs17.4-34.8 Wo0.9-35.2) and plagioclase(Ab5.8-10.4 An89.2-94.2 Or0.0-0.3) with some olivine(Fo58.6-63.0 Fa37.0-41.4). It is also almost same bulk chemistry of howardite, such as typical howardite Yamato-791157 polymict breccia.The quite unique texture of the specimen might be indicated that this specimen is impactite with howardite compositions. However author expected that the meteorite specimen is the first howardite with unbrecciated-holocrystalline texture originated by the magma process on the HED(Howardite-Eucrite-Diogite) parent body possible asteroid 4 Vesta. The bulk chemical compositions of the specimen 1152 meteorite is 49.50SiO_2,0.09TiO_2,7.34Al203,6.28Fe_2O_3,9.73FeO,0.37MnO,19.02Mg0,5.58CaO,0.19Na_2O,<0.02K20,0.1H_2O(+),0.10H_2O(-),0.21P_2O_5,0.52Cr_2O_3,1.42FeS,<0.1Fe, and tatal 100.57 in weight percent(%).