中国东部中-新生代玄武质火山岩的主量元素地球化学特征

用MgO=8％标准化后，中国东部中-新生代玄武质火山岩表现为高Al2O3／TiO2、SiO2，低CaO／Al2O3的特征；新生代玄武质火山岩表现为低SiO2和低Al2O3／TiO2；高Fe8.0、Na8.0、CaO／Al2O3的特征。与区域软流圈地慢上涌和岩石圈伸展构造环境下形成的桂东南钾玄质岩石的高Fe8.0、低Na8.0和CaO／Al2O3值有明显的差异。中国东部中一新生代玄武质火山岩主量元素的特征，可能反映了与桂东南钾玄质岩石不同的形成环境。而中、新生代玄武质火山岩主量元素特征上的差异反映了岩浆来源区的变化。

Geochemical Characteristics of Major Elements of Mesozoic-Cenozoic Basaltic Rocks from Eastern China

The MgO=8% normalized lithochemical compositions of Mesozoic basaltic rock from eastern China show high ratios of Al2O38/TiO2 , high contents of SiO2 and low ratios of CaO/Al2O3. However, those of the Cenozoic basaltic rocks show features of low SiO2 contents, low ratios of Al2O3/TiO2 and high contents of Fe8.0* and Na8.0, and high ratios of CaO/Al2O3 These are obviously different those (high Fe8.0* and low Na8.0, CaO/Al2O3 of the shoshonitic rocks, which were believed to have been formed by ascending of athosphere and stretching of hthosphere, from southeast Guangxi Province. This indicates that the tectonic background for the formation of Mesozoic-Cenozoic basaltic rocks in eastern China is different to that for the formation of the shoshonitic rocks in southeastern Guangxi. The major elemental geochemical variations between the Mesozoic and Cenozoic basaltic rocks in the eastern China reflect that they were derived form different magma sources.