吉林东部塔东铁矿区雁脖岭岩体和朱敦店岩体的形成时代与构造背景分析  

Formation age and tectonic setting of Yanboling and Zhudundian plutons in Tadong iron deposit,eastern Jilin Province

作　　者：周静[1] 李本仙[1] 梁一鸿[1] 于泓超 孙晓[1] 

机构地区：[1]吉林大学地球科学学院,长春130061

出　　处：《世界地质》2016年第1期142-152,共11页World Geology

基　　金：中国地质调查局项目(1212011120329)资助

摘　　要：通过LA-ICP-MS锆石U-Pb定年和岩石化学分析,研究了吉林省塔东铁矿区雁脖岭岩体和朱敦店岩体的形成年代、地球化学特征和形成环境。岩石地球化学特征显示雁脖岭岩体为花岗闪长岩岩体,朱敦店岩体为花岗岩岩体。两个岩体的加权平均年龄分别为262.3±3.1 Ma和244.5±1.9 Ma,是二叠纪末和三叠纪初的侵入体。雁脖岭岩体的含铝指数A/CNK=0.88~0.94,里特曼指数σ=2.09~2.45,Na2O/K2O=1.45~1.69;朱敦店岩体的含铝指数A/CNK=0.902~1.001,σ=2.15~2.55,Na2O/K2O=0.99~1.12。地球化学特征表明两者均属于准铝质的I型花岗岩,源区具有壳源性质,是古亚洲洋板块俯冲产物。朱敦店岩体的侵入年龄表明古亚洲洋在224 Ma±仍未闭合。The geochronology,geochemical characteristics and tectonic setting of Yanboling and Zhundundian plutons from Tadong iron deposit area are studied with zircon LA-ICP-MS dating. Geochemical characteristics suggest that Yanboling pluton is of granodiorite and Zhundundian pluton is of granite. The weighted mean ages of the two plutons are 262. 3 ± 3. 1 Ma and 244. 5 ± 1. 9 Ma,indicating the intrusions are the Late Permian to the Early Triassic in ages,respectively. The Na2O / K2O ratios of Yanboling pluton are 1. 45 ~ 1. 69,A / CNK values are0. 88 ~ 0. 94,while Rittmann index σ as 2. 09 ~ 2. 45. Zhundundian pluton has Na2O / K2O ratios of 0. 99 ~ 1. 12,A / CNK values of 0. 902 ~ 1. 001,Rittmann index σ as 2. 15 ~ 2. 55. The geochemical features indicate that Yanboling and Zhundundian plutons are metaluminous I-type granites and they both have the characteristics of crust source,which were producted by the subduction of the Paleo-Asian Ocean plate. The instrusion age of the Yanboling pluton signify the Paleo-Asian ocean not closed in ca. 244 Ma.

关 键 词：塔东铁矿区 锆石U-PB定年 花岗岩 形成环境 吉林东部 

分 类 号：P597[天文地球—地球化学] P542.4[天文地球—地质学]