U-Pb-Hf isotopes of Neoarchean Shuimowan tonalites in southern margin of North China Craton: constraints on petrogenesis

作者：HAO Leran,YANG Haotian,YANG Donghong

摘要：This study presents zircon LA-ICP-MS U-Pb geochronology,trace elements characteristics,whole rock geochemistry composition and zircon Hf isotopic data of Shuimowan tonalites in Dengfeng City.The results show that zircons from Shuimowan tonalites have oscillatory growth zoning,relatively high Th/U ratios(0.8--1.7)and upturned zircon rare earth elements(REE),indicating that they are magmatic origin.Shuimowan tonalites yield a weighted mean 207 Pb/206 Pb age of 2522±9 Ma,indicating they were formed in the latest Neoarchean.The tonalites are characterized by relatively low SiO 2 contents,high MgO and Na 2O contents,high REE(∑REE=322×10-6-354×10-6),obvious fractionation of REE,enrichment in LREE and feeble negative Eu anomaly(Eu/Eu*=0.97--0.99).The samples are also enriched in large ion lithophile elements and depleted in high field strength elements,with negative Nb,Ta,P and Ti anomalies.TheεHf(t)values of zircon grains from Shuimowan tonalites range between 3.5 and 5.3.Combined with regional tectonic evolution,it is suggested that Shuimowan tonalites were derived from partial melting of mantle peridotite metasomatized by the slab-derived felsic melt and formed in the arc magma tectonic setting related to plate subduction.Research on the Neoarchean Shuimowan tonalites provides a constraint for the study of the Pre-Cambrian tectonic evolution in the southern margin of North China Craton.

发文机构：College of Earth Sciences International Center for Geoscience Research and Education in Northeast Asia

关键词：TONALITENEOARCHEANPETROGENESISHfisotopeNorthChinaCraton

分类号： P59[天文地球—地球化学]