地质学报2017，Vol.91Issue(10)：2151-2174,24.
扬子地块西、北缘中元古代地层的划分与对比
Subdivision and Correlation of the Mesoproterozoic Stratigraphy in the Western and Northern Margins of Yangtze Block
摘要
Abstract
The Mesoproterozoic strata,distributed in the western and northern margin of Yangtze block,have experienced strong deformation and lower to upper greenschist-facies metamorphism.Based on previous study and formation ages,Mesoproterozoic can be divided into two stages:the Early Mesoproterozoic (1.8～1.4Ga) and Late Mesoproterozoic (1.4 ～ 1.0Ga).The Early Mesoproterozoic strata (1.8 ～ 1.4Ga)contains Dahongshan Group,Dongchuan Group,Hekou Group and Tong'an Formation (1～4 Member),while the Late Mesoproterozoic (1.4～1.0Ga) is composed mainly of Kunyang Group,Huili Group in the southwestern part of the block,and Shennongjia Group and Dagushi Group in the northern part of the block in the Late Mesoproterozoic.New zircon U-Pb geochorology data indicate that the tuff of the Tong' an Formation and the quartz-keratophyrite of the Hekou Group formed at 1744± 14Ma and 1659-±-23Ma,respectively,and the mafic dyke intruded into the Huili Group at 1026± 7Ma.According to the sedimentary succession,formation environment and geochronological data,the Dahongshan Group,Dongchuan Group,Hekou Group and Tong' an Formation formed at almost same time and have similar compositions.They all are related to IOCG (Iron-Oxide-Copper-Gold) or SSC (Sediment-hosted Stratiform Copper) formed in an extensional environment during 1.75～1.45Ga.The Huodiya Group in the northern margin of the Yangtze Block may belong to the Early Mesoproterozoic.Late Mesoproterozoic strata are also present in the western and northern margin of the Yangtze Block,including Kunyang and Huili groups in the southwestern margin of Yangtze Block were formed in 1.2 ～ 1.0 Ga;Shennongjia and Dagushi groups in the northern margin of the block formed during 1.4 ～ 1.0Ga,with the top of them probably extending to the Early Neoproterozoic.A large amount of stromatolite was also found to occur in the Mesoproterozoic strata,indicating that they formed in a warm,humid shallow sea environment.Besides the Mesoproterozoie strata mentioned above,the Julin Group in the Yuanmou area of Yunnan province,and the Dengxiangying Group and fifth Member of the Tong'an Formation in western Sichuan province all belong to the Late Mesoproterozoic.关键词
中元古代早期/中元古代晚期/地层划分与对比/锆石年代学/扬子克拉通西—北缘Key words
Early Mesoproterozoic/Late Mesoproterozoic/stratigraphy subdivision and correlation/zircon geochronology/western and northern margins of Yangtze Block引用本文复制引用
耿元生,旷红伟,柳永清,杜利林..扬子地块西、北缘中元古代地层的划分与对比[J].地质学报,2017,91(10):2151-2174,24.基金项目
本文由国家自然科学基金(41472082)、国家重点研发计划深地资源勘查开采重点专项(No.2016YFC0601001)、中国地质调查局项目(12120115068901)资助的成果. （41472082）
