Geochemistry And Detrital Zircon Comparison Of Metamorphic Sandstone In Wutai Group And Hutuo Group Of The North China Craton

The Wutai area in the central North China Craton is one of the typical area of the Early Precambrian rock exposure in China.The Archean Wutai Groups of metamorphic sandstones and the Hutuo metamorphic sandstones have always been the focus of Precambrian study.At this stage,the material source,sedimentary age and tectonic setting of the Wutai Groups and the Hutuo Group are mainly concentrated Research.Therefore,on the basis of detailed field observation,through the U-Pb dating and geochemical analysis of the two types of metamorphic sandstone,combined with the data of the zircon age and geochemistry of the Wutai Groups in the Hutuo Group and the Hutuo group obtained by the predecessors,the tectonic environment is discussed.The main peak of the age spectrum of the Hutuo Group of metamorphic sandstone is 2530 Ma,a secondary peak near 2.2 Ga,combined with geochemical data,indicating that the Hutuo metamorphic sandstone is relatively complex,showing five granite in about 2 billion 500 million years,as well as the Hengshan and Fuping TTG gneiss,as early as 2 billion 100 million years ago.In the Proterozoic granites,the youngest zircon age of the Hutuo Group is 2223 Ma,so it is possible to infer that the Hutuo Group of detrital zircons can be deposited after 2.2 Ga,and the Hutuo Group metamorphic sandstone has a low La and high Zr and Hf content,which suggests that the tectonic environment is the passive continental margin.The main peak of U-Pb age spectrum of the detrital zircon of the Wutai Groups of metamorphic sandstone is 2540 Ma,the secondary peak in the vicinity of 2.7 Ga and the relative concentration of geochemical data infer that the material source of the Wutai Groups of metamorphic sandstone is relatively single,which may be the gneiss of the Fuping area of Hengshan,and the youngest Wutai Group metamorphic sandstones obtained are the youngest.The age of zircon is 2506 Ma,and it is considered that the sedimentary age of the Wutai Groups of metamorphic sandstone is after 2506 Ga.At the same time,it is found that the tectonic environment of the Wutai Groups of metamorphic sandstone is an active continental margin environment.At the same time,in the study of structural environment,it is found that the main elements such as K and Na are unstable,which is not of critical significance to the structural environment discrimination of metamorphic sandstone.