In an attempt to use zircon to preliminarily explore the abundance of uranium and thorium in the earth's interior,3 ultramafic samples,52 mafic samples,46 intermediate igneous samples,and 90 acid igneous samples,totaling 191 samples with 6,979 zircon dating data (3,552 for U and 3,427 for Th),were mastered by collecting the U-Th-Pb isotopic dating in the literature invovled about Caledonian igneous zircons from the Qinling Orogen.The data results indicate that the U content in zircon in the same type igneous samples are quite different,as well as the Th,and both can be enriched or loss in different types of magmatic zircons, without the overall increasing trend from ultramafic,mafic,intermediate,to acid rocks.In addition,in all samples,45 highly enriched samples with an average U and Th contents more than 2 times,34 of which exhibit the characteristics of "local long-term" distributions as follows:ten 451.0~422.1 Ma mainly of OIB type mafic and intermediate igneous samples from Daba Shan area of the southern Qiling Orogen,most of which show the magma were derived from mantle magma source of HIMU,EMII and EMI;twenty-four 495.9~413.6 Ma mainly of I-type and S-I type acid igneous samples collected from the northern Qinling Shangdan (Shangnan-Danfeng) area,most of which show the magma were derived from mantle,crust-mantle and crustal source areas.Combined with the discovery of U metal (0 valence) in South China and other previous researches,it is preliminary belived that a mantle plume and a continental hot spot exsit in Daba Shan and Shangdan area during Caledonian period,respectively,and a large amount of U and Th in the earth's core rise along the mantle plume and continental hot spots,resulting in long-term enrichment of U and Th in the local melts of mantle and crust,the ultrahigh contents of which are partly recorded by zircons in the melting,this process of element migration may be the main reason for producing high zircon U and Th samples in these two areas, and the reason for generating U deposits in Shangdan area.Our results possibilily support the hypothesis that U and Th could be enriched both in the core and mantle plumes.