【摘要】 本文报道了东昆仑造山带三叠纪辉长岩、花岗岩类及其包裹体的Pb、Sr、Nd和O同位素组成。东昆仑造山带花岗质岩石全岩和长石Pb同位素组成相差不大 ,具明显的造山带Pb同位素特征 ;Sr同位素初始值 (ISr)变化于 0 .70 14 4～ 0 .70 972之间 ,暗示幔源成因 ;εNd值变化于 - 4 .4 9939～ - 9.192 5 8之间 ,具壳源成因特点 ;Nd同位素模式年龄 (tDM)在 1.38～ 1.76 1Ga之间 ,与中元古代变质岩相当 ;O同位素组成变化范围 7.8～ 9.5 ,表明花岗岩类成岩物质主要来自地壳。综合岩石的同位素组成 ,结合矿物学、岩石地球化学的研究 ,表明花岗岩浆主要起源于地壳 ,但与来自地幔的基性岩浆曾发生过混合作用 ,从而导致同位素组成趋于一致更多还原

【Abstract】 This paper reports Pb, Sr, Nd and O isotopic compositions of gabbro and granitoids formed in East Kunlun orogenic belt in Triassic. Granitoids and potassic feldspar have similar Pb isotopic compositions. Studies show that they were formed in an orogenic environment.Initial ( 87Sr/ 86Sr)t ratios range from 0.70144 to 0.70972,and εNd values from -4.49939 to -9.19258. Nd isotopic model ages (t DM) vary from 1.38 Ga to 1.761 Ga, being close to the age of mesoproterozoic metamorphic rocks. O isotopic compositions range from 7.8 to 9.5, indicating that the granitoids were derived from the crust. Based on all isotope data and mineralogical as well as petrochemical studies, it is held that the granitoids were mainly derived from the crust and mixed with the mantle-derived materials. The mixing process between the crust materials and the mantle-derived materials is responsible for the nearly identical isotope compositions.更多还原