南辽河群斜长角闪岩的地球化学特征及地质意义:以三家子地区为例  

Geochemical characteristics of amphibolite of South Liaohe Group and their geological significance:a case study of Sanjiazi area

作　　者：李富强[1] 董永胜[1] 王鹏森[1] 高铂森 甘宜成[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》2017年第1期82-92,共11页World Geology

基　　金：华北克拉通及周缘关键地质问题调查与变质岩试点填图项目(DD20160121)资助

摘　　要：基于详细的野外地质调查,对南辽河群下部里尔峪组斜长角闪岩进行了岩相学和地球化学研究。岩相学研究表明,南辽河群下部里尔峪组斜长角闪岩属于正变质岩。地球化学研究显示,这些斜长角闪岩原岩属于高铁拉斑玄武岩系列(Nb/Y=0.16~0.4),SiO_2含量为47.27%~50.68%,具有较低的TiO_2含量(0.92%~1.61%),亏损高场强元素(Nb、Ta、Zr、Hf等),表明其原岩形成于岛弧或活动大陆边缘,而非前人所说的大陆裂谷。综合岩相学和地球化学特征,初步认为其岩石成因与活动大陆边缘有关。On the basis of detailed field geological survey,the authors undertook petrographic and geochemical analysis of the amphibolites in Lieryu Formation of lower South Liaohe Group. Petrographic studies show that the amphibolites in Lieryu Formation are orthometamorphite. Geochemical data indicates that the amphibolites belong to high Fe tholeiitic series（Nb/Y = 0. 16 ~ 0. 40）,with the content of SiO_2 of 47. 27% ~ 50. 68%,and low TiO_2 content of 0. 92% ~ 1. 61%. They are depleted in high field strength elements such as Nb,Ta,Zr and Hf,indicating that their original rocks were formed in an island arc or active continental margin,rather than the continental rift defined by previous studies. Integrating petrographic and geochemical characteristics,it is preliminarily concluded that the petrogenesis is related to the active continental margin.

关 键 词：南辽河群 斜长角闪岩 地球化学 高铁拉斑玄武岩 岛弧环境 活动大陆边缘 

分 类 号：P595[天文地球—地球化学]