湖北太平溪超镁铁岩的地球化学初步研究

湖北宜昌太平溪超镁铁岩岩石化学和微量元素地球化学特征表明，其岩石化学成分相对稳定，具狭窄的ｍｇ＊，ＭｇＯ／ＭｇＯ＋ＦｅＯ比值，亏损稀土元素、不相容元素，而富集相容元素，具富ＬＲＥＥ配分模式特征，属阿尔卑斯残留地慢岩，是原始地幔岩经历３０％以上部分熔融后形成的，并受到了富ＣＯ２＋Ｈ２Ｏ，ＬＲＥＥ交代流体所影响。样品５可能是原始地馒岩在高度部分熔融（Ｆ＞８０％）下的产物，其化学成分反映出了原始地慢岩的成分属性。

GEOCHEMICAL RESEARCH ON THE TAIPINGXI ULTRAMAFITE, HUBEI PROVINCE

The paper systematically researched the geochemical characteristics of the Taipingxi ultramafite. The results showed that the ultramafite has relatively stable lithochemical composition, which is characterized by 1 ) the limited Mg and MgO/ (MgO+FeO), 2) the depletion of both REE and imcompatible elements but the beneficiation of compatible elements, and 3) hign LREE/HREE ratio. These charocteristics show that the untramafite is Alpine type's one - -the remainer of highly panal melted mantle rock, which accepted metasomatism of both CO2+H2O and LREE fluid. In addition, it is sugested that the sample 5, whose whole rock composition is thought to be the representative of the primitive mantle rock possiblily formed by partial melting that the degree of partial melting is over 80%.