Distribution Characteristics and Geological Significance of U-Pb Age of Detrital Zircon in Yanchang Formation of Yanhe Strata Section of Ordos Basin

In our study,we measures the U-Pb age of detrital Zircon in the middle and lower formation of Upper Triassic Yanchang Formation in Yanhe Section of Ordos Basin,the results show that the most outstanding Zircon U-Pb age of the samples are 2 271-2 567 Ma and 1 599-1 937 Ma,and five zircons having a small amount of young magma zircon have a U-Pb ages of 261-285 Ma.The study shows that the time interval of 2 271 Ma and 2 567 Ma with a peak of about 2 500 Ma is an effective evidence for the activity of mantle adding related to basaltic magma in the late Late Archean in North China Craton.While the time interval of 1 599 Ma and 1 973 Ma with a peak of about 1 800 Ma is an effective evidence for tectonic heat event initiated by continent-continent collision of Columbia Supercontinent during the Palaeoproterozoic and the structure movement during the Mesoproterozoic in North China Craton.Magma zircon age distributed between 261Ma and 285Ma of the five zircons is the main evidence for magma intrusion activity during the Early Indo-Chinese.In this paper,we used the detrital zircon age to determine that the Craton provenance of North China from which the clastic sediments of Yanhe Strata Section come from in the interval of about 2500Ma,that is,from the Late Archaean,Palaeoproterozoic deeply metamorphosed diorite,gneiss and granulitite of Yinshan Mountain.