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水泉沟杂岩体的δ１８Ｏ‰值除个别样品高于１０‰或低于５．５‰外，大多数在５．５‰～１０．０‰之间。其三组铅同位素比值明显高于本区太古界桑干群变质岩，并位于上地幔和下地壳铅增长线之间。利用ＲｂＳｒ等时线求得锶同位素初始值为０．７０６１８±０．０００１４，利用Ｆａｕｒｅ［１］提出的二元混合锶模型求得岩浆源区由约６４％的上地幔组分和约３６％的地壳组分组成。通过对其Ｏ、Ｐｂ和Ｓｒ同位素综合分析后得出，岩浆起源于上地幔的顶部和下地壳底部的过渡带，同时岩浆在高位岩浆房中和上升过程中也发生了不同程度的同化混染作用
The δ18O ‰ value of Shuicheou complex is mostly between 5.5 ‰ ~ 10.0 ‰, except for some samples higher than 10 ‰ or lower than 5.5 ‰. The Pb isotopic ratios of these three groups are significantly higher than those of the Proterozoic Sanggan Group metamorphic rocks in the region and lie between the upper mantle and the lower crust Pb-Pb line. The initial value of strontium isotope calculated by the RbSr isochron is 0.70618 ± 0.00014. Using the binary mixed strontium model proposed by Faure [1], the magma source region consists of about 64% of the upper mantle component and about 36% of the Crust composition. Based on the comprehensive analysis of O, Pb and Sr isotopes, the magma originated from the transition zone between the top of the upper mantle and the bottom of the lower crust. At the same time, the magma also experienced assimilation and contamination effect