赣南地区寒武纪高滩组碎屑锆石U-Pb年龄和Hf同位素特征及地质意义  

Detrital Zircon U-Pb Ages and Hf Isotopes of the Cambrian Gaotan Formation in Gannan and Its Geological Significance

作　　者：马虎超 徐文坦 钟康惠[1] 龚安州 郭坤一[2] 杨川 Ma Huchao;Xu Wentan;Zhong Kanghui;Gong Anzhou;Guo Kunyi;Yang Chuan(Chengdu University of Technology,Chengdu,Sichuan,610059,China;Nanjing Institute of Geology and Mineral Resources,Nanjing,Jiangsu,210016,China;Hebei GEO University,Shijiazhuang,Hebei,050031,China)

机构地区：[1]成都理工大学,四川成都610059 [2]南京地质矿产研究所,江苏南京210016 [3]河北地质大学,河北石家庄050031

出　　处：《新疆地质》2019年第2期270-277,共8页Xinjiang Geology

基　　金：中国地质调查局地质调查项目(DD20160015-26和12120115030101)联合资助

摘　　要：寒武纪高滩组广泛分布于赣南武功山-雩山地区,主体为一套浅变质砂岩夹板岩的复理石建造。为分析其物源,并对源区地壳生长和构造演化提供约束,本文对采自高滩组的变长石石英杂砂岩进行了LA-ICP-MS碎屑锆石U-Pb年代学和Hf同位素研究。锆石U-Pb年龄数据显示2 500 Ma、1 100~900 Ma和900~700 Ma 3个主要年龄峰值。2 500 Ma的年龄峰值代表了新太古代末期—古元古代的古陆核生长事件。1 100~900 Ma和900~700 Ma两个峰最显著,表明Rodinia超大陆聚合裂解在华南地区的响应,为该区寒武纪地层提供了主要物源。此外,3 003 Ma锆石年龄的捕获说明,华夏地块可能存在太古宙地壳基底。Hf同位素数据表明,源区锆石结晶多为古老地壳组分部分熔融产生的岩浆。结合锆石年龄数据分析认为,华南地区存在强烈的新元古代岩浆活动,该时期岩浆活动主要是古老地壳物质的再循环。The Cambrian Gaotan Formation is widely distributed in the Wugongshan-Yushan area of Gannan.It is mainly a set of flysch composed of low metamorphic sandstone and slate.The researchers have little research about it and lack of the latest data.In order to analyze its provenance and provide constraints on crustal growth and tectonic evolution in the source area, the LA-ICP-MS detrital zircon U-Pb geochronology and Hf isotope study were carried out on a sandstone from the Gaotan Formation.The U-Pb age data shows three peaks of 2 500 Ma, 1 100~900 Ma and 900~700 Ma. The age peak of 2 500 Ma represents crustal growth event in the late Neoarchean-Paleoproterozoic.The two peaks of 1 100~900 Ma and 900~700 Ma are the most significant,which indicates that the response of the amalgamation and breakup of the Rodinia supercontinent in southern China provides the main provenance for the Cambrian strata in study area. In addition,the capture of 3 003 Ma sugggets that the Cathysia block may have the Archean crustal base;Hf isotope data indicates that most of the zircon in the provenance region crystallized from the magma produced by partial melting of the ancient crustal materials.Combined with the analysis of zircon age data,there is a strong Neoproterozoic magmatism in South China,and the magmatism during this period is mainly the recycling of the magma produced by the melting of ancient crustal materials.

关 键 词：赣南 高滩组 锆石U-PB测年 HF同位素 物源分析 地壳生长 

分 类 号：P597[天文地球—地球化学] P[天文地球—地质学]