【摘要】 地球化学研究表明,大蒲柴河岩体具有典型的埃达克岩特征,来自加厚下地壳的部分熔融作用。本文采用激光等离子质谱对该岩体进行了U-Pb同位素定年,结果表明该岩体为晚侏罗世（165Ma）岩浆活动的产物。锆石的LA-MC-ICPMS Hf同位素研究结果显示,ε_Hf（165Ma）范围为-5.02～5.43,二阶段Hf模式年龄(t_DM2范围为965～1622Ma,暗示原始母岩浆为两种不同源区岩浆的混合。另外,Hf同位素研究表明,研究区在中-新元古代时（965～1304Ma）曾经历了一次重要的地壳增生事件。更多还原

【Abstract】 Based on geochemical evidence,the quartz diorites from Dapuchai,eastern Jilin Province,belong to typical adakites derived from partial melting of thickened lower crust.Zircon U-Pb dating by LA-ICPMS technique indicates that the studied plutons were emplaced during Late Jurassic with an age of 164.9±0.8Ma.Zircon Hf analyses conducted by LA-MC-ICPMS show that these adakites have variationalε_Hf（165Ma） values from -5.02 to 5.43,and _Hf model ages from 965Ma to 1622Ma,indicating that the primary magma of the adakites originated from mixing of two different magma,one from partial melting of pre-existing crustal source that was separated from a depleted mantle source during the Middle Proterozoic;While the other magma from asthenospheric mantle through underplating during 985～1304Ma,indicative of an important crustal growth beneath the studied area.更多还原