摘要
张广才岭位于黑龙江省中南部和吉林省中部,区内发育的南北向岩浆弧是微板块碰撞-拼贴的产物,能有效限定松嫩地块和佳木斯地块的碰撞-拼合时代。本文以张广才岭南部青松乡中侏罗世似斑状二长花岗岩为研究对象,开展系统的锆石U-Pb年代学和岩石地球化学研究,探讨其地质意义。锆石U-Pb年代学研究结果显示:张广才岭南部青松乡似斑状中细粒二长花岗岩成岩年龄为(172.1±1.3)Ma,似斑状中粗粒二长花岗岩成岩年龄为(172.1±1.2)、(172.4±1.2)、(172.2±1.7)Ma,为中侏罗世早期。岩石元素地球化学研究结果显示:似斑状中细粒二长花岗岩和似斑状中粗粒二长花岗岩贫硅、贫铝,高碱、富钾,高TFeO/MgO值,稀土元素配分模式图为轻稀土元素富集、重稀土元素亏损的右倾型,相对富集Rb、K、U、Th、La元素,亏损Nb、P、Ti、Y、Yb、Lu元素,属于I型花岗岩,岩浆来源于壳幔混合源区。结合年代学和地球化学特征,研究区中侏罗世似斑状二长花岗岩形成于同碰撞构造环境,成岩构造环境与佳木斯地块和松嫩地块碰撞-拼合作用密切相关。
Zhangguangcai Range is located in the central-southern part of Heilongjiang Province and the central part of Jilin Province.The north-south magmatic arcs developed in the Zhangguangcai Range are the products of collision-collage of microplates,which can effectively determine the collision-collage age of Songnen block and Jimusi block.In this paper,systematic zircon U-Pb geochronology and petrogeochemistry of the Middle Jurassic porphyritic monzogranites in Qingsong,Southern Zhangguangcai Range,have been carried out to explore its geological significance.The zircon U-Pb geochronology shows that the petrogenic ages of porphyritic medium-fine grained monzogranites and porphyritic medium-coarse grained monzogranites are(172.1±1.3)Ma and 172.1-172.4 Ma respectively,indicating their diagenetic ages belong to the Middle Jurassic.Geochemical results indicate that the porphyritic monzogranites are low in Si and Al,high in alkali,K and TFeO/MgO values.The chondrite-normalized REE patterns of porphyritic monzogranites with a slight dipping to the right display enrichment in elements of(Rb,K,U,Th,La and LREE and depletion in elements of Nb,P,Ti,Y,Yb,Lu and HREE The porphyritic monzogranites belong to type I granites,and their magma originatesd from the crust-mantle mixed source area.Combined with the characteristics of chronology and geochemistry,the Middle Jurassic porphyritic monzogranites were formed in the syncollisional tectonic setting,which is closely related to the collision-collage of the Jiamusi block and the Songnen block.
作者
张国宾
陈兴凯
赵越
唐佳雨
李瑞瑞
冯玥
孔金贵
Zhang Guobin;Chen Xingkai;Zhao Yue;Tang Jiayu;Li Ruirui;Feng Yue;Kong Jingui(Mining Institute,Liaoning Technical University,Fuxin 123000,Liaoning,China;Institute of Innovation and Development for Fuxin Transition,Liaoning Technical University,Fuxin 123000,Liaonig,China;Chemical Geological Prospecting Institute of Liaoning Province Co.,Ltd.,Jinzhou 121007,Liaoning,China)
出处
《吉林大学学报（地球科学版）》
CAS
CSCD
北大核心
2022年第6期1907-1925,共19页
Journal of Jilin University：Earth Science Edition
基金
中国地质调查局项目(1212011120342)
辽宁省科技厅面上基金项目(20170540428,201601370)
辽宁省教育厅基金项目(LJ2019JL027)
