峨眉山玄武岩地幔源成分及其变化的微量元素标志

根据峨眉山玄武岩系岩石的稀土元素、不相容元素特征，估计了产生其母岩浆的地幔源成分，在讨论了地幔平衡部分熔融和岩浆分离结晶过程中强不相容元素与一般不相容元素的比值变化后，提出用双对数图解来判别地幔成分、元素总分配系数及母岩浆形成时地幔熔融度的原理。根据Ｌａ，Ｃｅ和Ｓｃ，Ｙｂ在地幔－岩浆过程中地球化学特征，运用上述原理，讨论了峨眉山玄武岩系母岩浆的地幔成分及其变化，计算了地幔矿物相组成和部分熔融度。

TRACE ELEMENTAL INDICATER FOR MANTLE SOURCEI S MINERAL COMPOSITIONS AND THEIR VARIATION DURING MAGMA PROCESSES IN EMEISHAN BASALTS,SOUTHWESTERN CHINA

Based on the characteristics of rare earth elements and incompatible elements in the rocks ofEmeishan B8salts, this paper e6timates the composition of mantle source from which the primary magma derives, discusses the chanses of ratios of strons incompatible elementS to ordinary incompatible edements during mantle partial melting and magma fractional crystallization,and demonstrates the discriminant principle of mantle source composition I distribution coefficience of element and degree ofpartial meltins durins formation of primary masma on the diaSraln of logarithm--logarithm. In termsof the above principle and the geochemical character of La, Ce,Sc,Yb durins mantle--magma processes, the paper also discusses the mantle components of primary masma of Emeishan Basalts and theirchanges, and calculates the mineral composition and the degree of the partial melting of the mantle.