COMPARISON OF PRECAMBRIAN BASEMENTS BETWEEN THE JIAOBEI TERRANE AND THE NORTH SULU UHP METAMORPHIC BELT, JIAODONG AREA IN EAST CHINA

The ultra high pressure (UHP) metamorphic rocks in the Sulu UHP metamorphic terrane are directly in contact with the Precambrian basement of the Eastern Block of the North China Craton in Jiaodong area,East China. The Jiaodong area, therefore, becomes the key area to compare the differences of Precambrian basements between the North China Craton and the Yangtze Craton,and the key area to identify the location of boundary between the two cratons. The research of the assemblage, geochemistry and chronology on the outcrops of the Precambrian rocks reveals that the Precambrian rock assemblage of the Jiaobei Terrane is mainly consisted of Ar-Pt₁ crystallized basement. The continental crust was appeared in Neoarchean (~2.7 Ga), and then started intracratonic sedimentation of Paleoproterozoic khondalite(1.9~2.1 Ga) after the tectonic event at 2.5 Ga,and finally it underwent the metamorphic event at 1.8 Ga. However,the northern Sulu UHP Terrane was made up by the bimodal magmatic rocks caused by the rifting of the Rodinia Supercontinent at Mid-Neoproterozoic (0.7~0.8 Ga). The old crust of Neoarchean-Paleoproterozoic was remained and its initial crust evolution might be started from Neoarchean or even earlier, and then it suffered a series of magma-volcano-metamorphic events during 1.8~2.2 Ga, finally the ancient and juvenile crusts were reworked by the bimodal magmatism, which was induced by the rifting of the Rodinia Supercontinent at mid-Neoproterozoic (0.7~0.8 Ga). On this basis, the tectonic affinity of the Jiaobei Terrane and the North Sulu UHP metamorphic belt and their boundaries were discussed.