大兴安岭中段白音高老组流纹岩年代学、地球化学及其地质意义  

Chronology,geochemistry of rhyolites from Baiyingaolao Formation in the middle part of Da Hinggan Mountains and its tectonic implications

作　　者：聂立军[1] 贾海明[2] 王聪[1] 卢兴波[1] 

机构地区：[1]吉林省区域地质矿产调查所,长春130022 [2]吉林省地质调查院,长春130061

出　　处：《世界地质》2015年第2期296-304,共9页World Geology

基　　金：中国地质调查局地质矿产调查项目(1212011120726)

摘　　要：对大兴安岭中段（阿尔山——柴河地区）白音高老组流纹岩进行了年代学、地球化学详细测试，结果表明：白音高老组流纹岩LA—ICP—MS锆石u—Ph表面年龄值为124．8～135．6Ma，加权平均年龄值为127．04-0．5Ma，形成时代为旱白垩世；岩石主体属高硅高钾弱过铝质钙碱性系列；稀土元素配分模式图呈右倾型，轻重稀土分馏明显（（La／／Yh）N=3．12～10．28，平均7．57），铕弱负异常（δEu=0．18～0．73，平均0．53）；大离子亲石元素Rb、Th、U相对富集，Ba、Sr明显亏损，高场强元素Zr较为富集，Ti强烈亏损。根据区域对比并结合他人研究成果，认为大兴安岭中段白音高老组流纹岩彤成干旱白垩世赧内伸展环培．与太平洋赧殃俯冲吴系密切．The testing results of chronology and geochemistry of rhyolites from Baiyingaolao Formation in the middle part of Da Hinggan Mountains indicate that the zircon U-Pb age is 124. 8 - 135.6 Ma, with weighted aver- age age of 127.0 ±0.5 Ma, belonging to Early Cretaceous. The rocks belong to high-SiO2, high-K peraluminous calc alkaline series. The REE pattern is rightward sloping with significant fractionation of LREE and HREE （ （ La/ Yb） N =3. 12 -10. 28, average as 7. 57） and slight negative Eu anolies. The rhyolites are characterized by enrich- ment in LILE （Rb, Th, U） and Zr, depletion in Ba, Sr and Ti. Combined with regional comparison, the au- thors consider that the Baiyingaolao Formation rhyolites formed in Early Cretaceous extension setting, which is clos- ey related with the subduction of Pacific plate.

关 键 词：大兴安岭 白音高老组 年代学 伸展环境 

分 类 号：P588.141[天文地球—岩石学] P597[天文地球—地质学]