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对沙麦花岗岩岩体进行主量、微量、稀土元素和Nd-Sm同位素地球化学特征分析,主量元素显示为高钾钙碱性、过铝质,且P_2O_5随SiO_2含量增加而含量降低;微量元素显示大部分Y/Ho与Ⅰ型花岗岩演化趋势一致;稀土元素显示具有Eu负异常且Nb/Ta、K/Rb比值均小于相应的最高阀值,说明其经历了高度分离结晶作用。岩石Nd-Sm同位素特征显示大部分样品ε_(Nd)(t)>0,正值被认为成岩物质来自地幔,结合花岗岩浆的演化特征进行综合分析,判定沙麦花岗岩的成因类型为Ⅰ型花岗岩。
The major and minor trace elements, rare earth elements and Nd-Sm isotope geochemical characteristics of the samaran granite bodies were analyzed. The main elements were high K calc-alkaline and perovskite, and the content of P 2 O 5 decreased with increasing SiO 2 content. The elements show that most of the Y / Ho are consistent with the evolution of type I granites. The REE shows Eu negative anomalies with Nb / Ta and K / Rb ratios less than their corresponding highest thresholds, indicating that they undergo a high degree of segregation. The Nd-Sm isotopic characteristics of rocks show that ε Nd (t)> 0 for most of the samples, and positive values of diagenesis are thought to originate from the mantle. Based on the analysis of the evolution characteristics of granite magma, the genetic type of granitic rocks is determined to be type I granite .