东乌旗中铁陨石硅酸盐地球化学特征及对成因的启示

发布时间：2018-04-27 13:32

  本文选题：东乌旗中铁陨石 + 橄榄石　； 参考：《极地研究》2013年04期

【摘要】：东乌旗中铁陨石是1995年在内蒙发现的、为数不多的降落型中铁陨石,由金属-硫化物和硅酸盐相紧密混合而成。硅酸盐相由角砾部分(主要为角砾状橄榄石和辉长岩岩屑)和非角砾部分组成。岩相学特征、主量元素成分及REE地球化学特征表明角砾状橄榄石、非角砾橄榄石和辉长质硅酸盐(辉长岩岩屑和除橄榄石外的非角砾部分)三者可能分别结晶自不同的岩浆源区。进一步的分析表明Mg含量非常高的角砾状橄榄石可能来自一个分异小行星的橄榄岩质地幔,非角砾橄榄石和辉长质硅酸盐可能和HED陨石具有相同的母体Vesta小行星。冲击碰撞导致两个小行星的物质发生了混合。冲击作用产生的高温(约1 200—1 450℃)使得被撞击小行星表壳玄武质和辉长质岩石发生混合重熔,熔体结晶后形成中铁陨石的辉长质硅酸盐。该温度下非角砾橄榄石和角砾状橄榄石均未发生重熔。该模型较好地解释了角砾状橄榄石、非角砾橄榄石和辉长质硅酸盐三者之间的不平衡现象。
[Abstract]:The Zhongtie meteorite in Dongwu Banner was discovered in Inner Mongolia in 1995. A small number of falling iron meteorites were formed from the close mixing of metal-sulphide and silicate phases. Silicate facies is composed of breccia (mainly breccia olivine and pyroxenite) and non-breccia. The petrographic characteristics, principal element compositions and REE geochemical characteristics indicate that gravelly olivine, Non-breccia olivine and pyrochlastic silicate (pyroxene and non-breccia except olivine) may be crystallized from different magmatic sources respectively. Further analysis shows that the gravelly olivine with very high mg content may come from the peridotite mantle of a differentiated asteroid, and that the non-breccia olivine and pyrochlastic silicate may have the same parent Vesta asteroids as the HED meteorites. The impact and collision resulted in a mixture of material from the two asteroids. The high temperature (about 1 200-1 450 鈩，

本文编号：1810934