Paleoproterzoic Tectonic Evolution Of The North-central North China Craton

The north-central North China Craton,located at the conjunction of the Trans-North China Orogen(TNCO)and the Khondalite Belt,is a key location for studying the Precambrian crustal evolution of the North China Craton(NCC).However,its Palcoproterozoic crustal evolution history has long been controversial.Zircon LA-ICP-MS U-Pb dating,Hf isotopic and whole rock major and trace element analyses were carried out on the granites and TTG gneisses from the Huai'an Complex.The results indicate that the Huai'an Complex had undergone two episodes magmatism:2.6-2.2 Ga and 1.9-1.7 Ga.It was a long-lived continental margin arc on the western margin of the Eastern Block during 2.6-1.7 Ga.It was in crustal vertical growth stage with subduction tectonic setting during 2.6-2.2 Ga,in transition stage from growth to reworking with slab roll back setting during 2.2-1.9 Ga,and in reworking stage with collision and post-collision setting during 1.9-1.7 Ga.Zircon LA-ICP-MS U-Pb dating,Hf isotopic and whole rock major and trace element analyses were carried out on the Khondalite series from the Jining Complex.The results indicate that the Jining Complex was a continental margin arc at late Paleoproterozoic.The Khondalite series crystallized from the greywacke melting during 2.10-1.88 G.The the magmatic zircons ages of the Paleoproterozoic granites in the TNCO was quantitatively ananlyzed by the local singularity analysis(LSA).Their geochemical elements was quantitatively ananlyzed by principal component analysis(PCA).Their magmatic zircons?Hf(t)data and TDMC data were analyzed.The results indicate that the TNCO had undergone three episodes magmatism:2.6-2.2 Ga,2.2-1.9 Ga and 1.9-1.7 Ga.The magmatic flare-ups in the TNCO during 2.6-2.2 Ga had asymmetry characteristic.The TNCO was in crustal vertical growth stage with subdction arc setting during 2.6-2.2 Ga.It was in transition stage from crustal vertical growth to reworking with intracontinental rift setting during 2.2-1.9 Ga.During 1.9-1.7 Ga,the Huai'an Complex collided with the Western Block first,then the other complexes in the TNCO collided with the Western Block gradually from the Huai'an Compelx to the north and south,respectivelly,accompanied by crustal reworking.The the magmatic zircons ages of the Paleoproterozoic granites in the Khondatlite Belt was quantitatively ananlyzed by the LSA.Their magmatic zircons ?Hf(t)data and TDMC data were analyzed.The results indicate that the Khondatlite Belt had undergone two episodes magmatism:2.55-2.3 Ga and 2.1-1.8 G.The Khondatlite Belt was in crustal vertical growth stage with subdction arc setting during 2.6-1.95 Ga.It was in crustal reworking stage with collision and post-collision setting during 1.95-1.7 Ga.The comprehensive analysis of the Paleoproteorozic tectonic evolution of the north-central NCC provides constraints for the evolution of the NCC,which is of great scientific significance.