吉中倒木河中侏罗世闪长岩地球化学特征、岩石成因及其构造环境  

Geochemical characteristics, petrogenesis, and tectonic environmentof Middle Jurassic diorite in Daomuhe, central Jilin Province

作　　者：邰彦德 刘大玮[2] 潘忠翠 刘哲 曹钟元 张勇[3] 孙凌云 TAI Yande;LIU Dawei;PAN Zhongcui;LIU Zhe;CAO Zhongyuan;ZHANG Yong;SUN Lingyun(Jilin Institute of Geological Sciences,Changchun 130012,China;Jilin Institute of Geological Survey,Changchun 130061,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;College of Earth Sciences,Jilin University,Changchun 130061,China)

机构地区：[1]吉林省地质科学研究所,长春130012 [2]吉林省地质调查院,长春130061 [3]中国地质科学院矿产资源研究所,北京100037 [4]吉林大学地球科学学院,长春130061

出　　处：《世界地质》2024年第4期463-478,共16页World Geology

基　　金：吉林省地质勘查基金项目(2016-07);吉林省自然科学基金项目(20220101161JC)。

摘　　要：为探讨吉中地区在中侏罗世的岩浆活动和构造背景,笔者选取倒木河闪长岩为研究对象,通过锆石U--Pb测年、全岩主微量分析对其成岩时代、地球化学组成、岩石成因和构造环境进行研究。LA-ICP-MS锆石U-Pb测年结果显示,倒木河闪长岩成岩年龄为174.5 Ma,表明该岩体侵位结晶于中侏罗世。全岩地球化学分析结果显示,岩石具有低硅、高铝以及相对富钠等特征,富集轻稀土元素(LREE)和Rb、K、Th、U等大离子亲石元素(LILE),相对亏损Nb、Ta、P、Ti等高场强元素(HFSE)。Nb/Ta、La/Nb和Th/Nb比值显示闪长岩体岩浆具有壳幔混源的特点,可能与来自俯冲板片的流体交代作用有关。结合地球化学特征和前人研究资料,认为倒木河闪长岩应该形成于与古太平洋板块俯冲相关的活动大陆边缘环境。To explore the magmatism and tectonic background of the central Jilin Province during the Middle Jurassic,the Daomuhe diorite was selected as the research subject.Through zircon U-Pb dating and whole-rock major oxides and trace element analysis,the study investigates the geochronology,geochemical composition,petrogenesis and tectonic setting.The LA-ICP-MS zircon U-Pb dating results show that the age of the diorite is 174.5 Ma,indicating that the intrusion crystallized during the Middle Jurassic.The rocks are characterized by low Si content,high Al and relative Na enrichment.They are enriched in light rare earth elements(LREE)and large ionic lithophile elements(LILE)such as Rb,K,Th,and U,but relatively depleted in high field strength elements(HFSE)such as Nb,Ta,P,and Ti.The Nb/Ta,La/Nb,and Th/Nb ratios indicate that the magmas of the diorite have characteristics of a mixed source from the crust and mantle,potentially related to fluid interaction from the subducting slab.Combined with the geochemical characteristics and data from previous studies,it is suggested that the Daomuhe diorite likely formed in an active continental margin environment associated with the subduction of the Paleo-Pacific Plate.

关 键 词：锆石U--Pb年代学 地球化学 岩石成因 构造环境 倒木河地区 吉林中部 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]