内蒙古大桦背I型花岗岩地球化学特征及其成因意义

GEOCHEMICAL CHARACTERISTICS AND PETROGENETIC IMPLICATION OF THE I-TYPE DAHUABEI GRANITE PLATON IN INNER MONGOLIA

摘要: 在大桦背花岗岩体区域地质和岩石学研究的基础上，运用X射线荧光光谱分析样品主量元素，采用电感耦合等离子体质谱对其样品进行了微量、稀土元素分析.同时结合前人的锆石年龄和Pb同位素数据，认为大桦背花岗岩为I型花岗岩，主要为古亚洲洋板块向华北板块多期俯冲过程中，中下地壳、成熟岛弧和大洋岛弧大面积部分熔融的产物，伴有少量地幔与未知含量的海洋沉积物及早期造山作用产物等物质的不同程度混合作用.

Abstract: Based on the regional geological and lithological study, the paper reports and analyzes some data of samples obtained from the Dahuabei granite pluton, including major and trace elements. Combining with previous zircon dating results and Pb isotopic data, it is concluded that the Dahuabei pluton belongs to I-type granite, which is the product of partial melting of middle and lower crust, mature island arc and oceanic island arc in large area during the multiple subduction processes of the Pale-Asian oceanic plate toward the North China plate, associated with the mixture of a little mantle magma, unknown amount of oceanic sediments and earlier orogenic products.