华东地质2026，Vol.47Issue(1)：29-49,21.DOI:10.16788/j.hddz.32-1865/P.2026.01.004
下扬子太古宙隐伏基底:南黄杂岩的厘定
The buried Archean basement in the Lower Yangtze region:constraints from the Nanhuang Complex
摘要
Abstract
The Yangtze Block is one of the major cratonic blocks in China,which has been an important frontier issue on Precambrian crustal evolution for a long time.However,because continuous cap sedimentation since Nanhua period resulted in scarce outcrops of the Archean to Paleoproterozoic basement,the substance com-position,tectonic attribute and evolution history of the Yangtze Block are not well constrained.Therefore,finding and identifying property and geochronology of the basement hidden below the cap are critical to tracing the Pre-cambrian geological evolution of Yangtze Block.Based on the core of Nanhuang Complex(hidden basement)sampled from deep drilling in the Lower Yangtze region,this paper presents an integrated study of zircon U-Pb and Lu-Hf isotopes for its orthogneisses.LA-ICP-MS zircon U-Pb dating yields the protolith ages of ca.2.71 Ga for two amphibole plagiogneisses,ca.2.51 Ga for two K-feldspar gneisseses,providing unambiguous evidence for the presence of Neoarchean basement in the northeastern Yangtze Block.Zircons from the amphibole pla-giogneisses exhibit εHf(t)values ranging from-2.6 to+3.6,corresponding to TDM2 model ages of 3.36-2.96 Ga.Similarly,zircons from the K-feldspar gneisses display εHf(t)values between-4.0 and-0.7,with TDM2 model ages of 3.29-3.08 Ga.These isotopic signatures indicate significant Early Archean(3.3-3.0 Ga)crustal growth be-neath the Lower Yangtze region.When our data is combined with the existing geochronological data in other parts of the Yangtze Block,it demonstrates that the Nanhuang and Yudongzi Complexes may record the same tectonic transition from arc-continent collision(2.7 Ga)to post-orogenic(2.5 Ga)in the northern Yangtze Block,repre-senting the Neoarchean global massive crustal reworking.Furthermore,the buried Nanhuang Complex likely par-ticipated in Yanshanian magmatism and associated mineralization events in the Lower Yangtze metallogenic province.关键词
下扬子/太古宙/隐伏基底/南黄杂岩/地壳演化Key words
Lower Yangtze region/Archean/buried basement/Nanhuang Complex/crustal evolution分类
天文与地球科学引用本文复制引用
陈志洪,张炜,段政,褚平利,马雪,杨祝良,赵玲..下扬子太古宙隐伏基底:南黄杂岩的厘定[J].华东地质,2026,47(1):29-49,21.基金项目
国家自然科学基金"下扬子早前寒武纪隐伏基底杂岩组成与构造演化(编号:42172220)"项目资助. （编号:42172220）
