Geological and geochemical characteristics of the Paleoproterozoic intrusions in Bengbu uplift, southeast North China Craton

North China landmass is the oldest landmass and one of the largest craton massifs in the world. Bengbu uplift is a part of the North China landmass, and its initial formation of continental crust is late Archean in the time limit. With the collisions and stitching of the Yangtze platform and North China continental block, the Bengbu uplift experienced complex evolution processes. In order to further explore the Paleoproterozoic magmatic activity in the Bengbu uplift, the authors updated the data of geochronologic and geochemical analysis. Based on field observation, geochronology and geochemistry of Paleoproterozoic intrusions in this area, the authors obtained zircon U-Pb ages of (2089±44)Ma and (2133±27)Ma for Zhuangzili and Muopanshan granites. The geochemical data show that granites have high-Na and low-K significantly, and belong to the quasi-aluminum supersaturated type. They are characterized by relative enrichment of LREE with a strong Eu negative anomaly and insignificant Ce anomaly. The elements of K, Nb, Sr, P and Ti are characterized by measurable depletion, and there exists relative enrichment of Rb, Th, U, Nd, Zr and Sm. Intrusion projection points are distributed in A type granite area in the discrimination diagram of genetic type. Nd twophase age (2.37-2.84 Ga) is consistent with the age of North China Craton formed in Archean, with 2.40-2.50 Ga being the main stage. ε_Hf(t) values vary between -9.77 and +9.59, with obvious differences, suggesting the complexity of the origin of the material, and the old two-phase Hf model age (2.27-2.96 Ga) suggests that the main material was derived during Neoarchean. The tectonic environment belongs to the granite category within the plate and non-orogenic tectonic environment, which implies its extensional tectonic setting.