胶北地块和北苏鲁超高压变质带前寒武纪基底对比研究

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

胶东地区苏鲁超高压变质岩系和华北克拉通东部陆块的前寒武纪变质岩系直接相连,由此它成为对比华北-扬子板块前寒武纪基底差异、研究华北-扬子板块界线的关键区域之一。对胶东地区前寒武纪岩石组合、地球化学和年代学的综合研究表明：胶北地块前寒武纪基底以太古宙-古元古代的结晶基底为主,～2.7Ga的造壳活动最为显著,经历了～2.5Ga的构造事件后接受了1.9～2.1Ga的孔兹岩系沉积,在～1.8Ga变质事件后地壳基本处于稳定状态,至震旦纪发育了亲华北的蓬莱群沉积;与胶北地块不同,北苏鲁以新元古代双峰式岩浆岩系为主,残留少量太古宙-古元古代的残留地壳,并经历了1.8～2.2Ga的构造事件,但主要记录Rodinia超大陆裂解期（0.7～0.8Ga）年龄。并对胶北地块和北苏鲁超高压变质带的构造归属以及二者界线进行了讨论。

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（～2.7Ga）,and then started intracratonic sedimentation of Paleoproterozoic khondalite（1.9～2.1Ga）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（0.7～0.8Ga）.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 1.8～2.2Ga,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（0.7～0.8Ga）.On this basis,the tectonic affinity of the Jiaobei Terrane and the North Sulu UHP metamorphic belt and their boundaries were discussed.