摘要
滇西云县—景洪一带广泛出露的中元古界团梁子岩组是一套与扬子基底岩系密切相关的中低变质沉积岩夹火山岩系,其形成时代、沉积充填序列及大地构造属性一直存在争议。出露于云县漫湾地区的团梁子岩组发育厚数米的绿片岩(原岩玄武岩)及绢云石英千枚岩(原岩流纹岩)。采集绢云石英千枚岩样品进行LA-ICP-MS锆石U-Pb定年,分别获得1497±14Ma的岩浆结晶年龄和893±17.3Ma、425±15.7Ma、321±27Ma的变质年龄。认为团梁子岩组中以绿片岩、绢云石英千枚岩为主体的原始沉积岩系形成于中元古代中期,在新元古代全球性的格林威尔造山过程中被青白口纪花岗岩侵入并发生变质作用;在古特提斯洋俯冲过程中,经历古生代造弧作用;同时还获单颗粒2310±15Ma的碎屑锆石,推测滇西云县地区应存在古元古代的结晶基底,由此可知,团梁子岩组应是扬子陆块褶皱基底岩系的组成部分。
The Middle Proterozoic Tuanliangzi Formation, widely exposed in the Yunxian-Jinghong area of western Yunnan, consists of a set of low and medium metamorphic sedimentary rocks intercalated with the Yangtze basement rock series. Its formation age, sedimentary filling sequence and tectonic attributes have been controversial. The Tuauliangzi Formation exposed in Manwan area of Yunxian County contains basalt and sericite quartz phyllite, several meters in thickness. In this study, the LA-ICP-MS zircon U-Pb dating of sericite quartz phyllite （D1016） was carried out, and the magrnatic crystallization age of 1497±14Ma and the metamorphic age ot：893± 17.3Ma, 425±15.7Ma and 321±27Ma were obtained respectively. It is considered that the original sedimentary rock series in the Tuauliangzi Formation, mainly composed of greenschist and sericite quartz phyllite, were formed in the middle of the Mesoproterozoic period, and were intruded and metamorphosed by the Qingbaikou granite during the Neoproterozoic global Greenwell orogenic process. During the Paleo-Tethys Ocean subduction, the Paleozoic arc metamorphism was experienced, and a single grain of 2310±15Ma detrital zircon was obtained. It is inferred that there should be an ancient crystalline basement of Guyuan in Yunxian area, western Yunnan. It can be concluded that Tuauliangzi Formation is an integral part of the folded basement rock series of Yangzi continental block.
作者
刘军平
胡绍斌
李静
孙柏东
孙载波
王伟
关学卿
徐桂香
LIU Junping;HU Shaobin;LI Jing;SUN Baidong;SUN Zaibo;WANG Wei;GUAN Xueqing;XU Guixiang(Yunnan Institute of Geological Survey,Kunming 650216,Yunnan,China)
出处
《地质通报》
CAS
CSCD
北大核心
2018年第11期2079-2086,共8页
Geological Bulletin of China
基金
中国地质调查局项目<云南1:5万二街
易门
鸣矣河
上浦贝幅区域地质调查>(编号:DD20160017)
<云南省1:5万诗礼
犀牛街
大河
老家库
哨街五幅区域地质矿产调查>(编号:DD20160016)和<云南区域地质调查片区总结与服务产品开发>(编号:DD20160345-02)
关键词
团梁子岩组
锆石U-PB测年
滇西云县地区
扬子基底
Tuanliangzi Formation
zircon U-Pb dating
Yunxian area
western Yunnan
Yangtze basement
