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。
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 variational epsilon(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 similar to 1304Ma, indicative of an important crustal growth beneath the studied area.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第12期3153-3164,共12页
Acta Petrologica Sinica
基金
国家自然科学基金(40634020
40673029)
西北大学大陆动力学国家重点实验室开放课题基金(08LCD08)联合资助
