Multistage Formation of Neoarchean Potassic Meta-Granites and Evidence for Crustal Growth on the North Margin of the North China Craton  

作　　者：Xiaowei Zhang Huafeng Zhang Ying Tong 

机构地区：[1]Laboratory of National Land Space Planning and Disaster Emergency Management of Inner Mongolia,Chifeng University,Chifeng 024000,China [2]Beijing SHRIMP Center,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [3]School of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China [4]Key Laboratory of Earthprobe and Geodynamics,Chinese Academy of Geological Sciences,Beijing 100037,China

出　　处：《Journal of Earth Science》2023年第3期658-673,共16页地球科学学刊（英文版）

基　　金：financially supported by the National Key Research and Development Program of China(Nos.2018YFC0603702,2017YFC0601301);the Open Fund from Sino Probe Laboratory(No.Sinoprobe Lab 202223);the National Natural Science Foundation of China(Nos.92162322,41372077,and U1403291);China Geological Survey(Nos.DD20190685,DD20160024,DD20160123,and DD20160345);IGCP Project 662。

摘　　要：The North China Craton(NCC)is one of the most complex cratons in the world.It underwent a series of tectonothermal events during the Neoarchean-Paleoproterozoic.The petrogenesis of potassic granitoids,the timing,and the style of Archean crustal growth are still debated.Systematic field and petrological stdudies on the potassic meta-granites from the Guyang-Chayouzhongqi region were carried out.New U-Pb ages,zircon Lu-Hf isotopic analyses,and whole-rock geochemical data were obtained.Two groups(~2.7 Ga and~2.5 Ga)of potassic meta-granites were recognized.The~2.7 Ga meta-granites are mainly A2-type,with variableεHf(t)values(-8.4 to+3.3)and Archean one stage model ages(T_(DM)=~3.0 Ga),indicating that their source was derived from ancient anatectic TTG-like granite and depleted mantle,which suggests that thin crust had formed in the Guyang-Chayouzhongqi region by~3.0 Ga.Similar to the K-rich granites in the NCC,most of the~2.5 Ga potassic meta-granites are typical of A1-type granite,and are enriched in Sm and Gd and depleted in Nb,Ta,P,and Ti.The ages and isotopic data indicate that the~2.5 Ga meta-granites were generated from juvenile crustal sources with Neoarchean TTGs.The overall zircon U-Pb and Hf isotopic data furthermore suggested that the~2.7 Ga event is the most important stage of magmatic accretion in the NCC,similar to other cratons.In contrast,reworking or metamorphic alteration was the main crustal process in the NCC at~2.5 Ga.

关 键 词：ZIRCON U-Pb age Lu-Hf isotope geochemistry potassic meta-granite crustal growth North China Craton 

分 类 号：P542[天文地球—构造地质学] P588.3[天文地球—地质学]