大兴安岭北端阿乌尼地区中生代杂岩体的岩浆混合作用

Magma mixing of the Mesozoic hybrid in the Awuni area at the northern end of the Da Hinggan Mountains,China.

通过外野地质特征、岩相学、岩石地球化学等方面的研究,从不同的角度论证了大兴安岭阿乌尼地区出露的岩浆杂岩体在成因上具有岩浆混合作用的特点。同位素上具低的Sr初始比值和正的εN(dt)值,明显具有幔源特点,而微量元素相对富集大离子亲石元素和高场强元素又具有壳源特征,表明阿乌尼地区的岩浆岩可能是壳幔相互作用的产物。

On the basis of studies of the field geological characteristics, petrography and geochemistry, the authors demonstrate from different aspects that the magmatic hybrid exposed in the Awuni area, Da Hinggan Mountains, has features of magma mixing in terms of the magmatic origin. Isotope study shows that the hybrid is characterized by low initial Sr ratios and positive εNd（t） values, showing obvious mande-derived features. On the other hand, the fact that trace elements are enriched as compared with large-ion lithophile elements and high field strength elements shows crustal-derived features, suggesting that magmatic rocks in the Awuni area might be the product of crust-mande interaction.