Archean Crustal Growth and Reconstruction of the Southern Margin of North China Craton: Constraints from the U-Pb-Hf Isotopic Compositions of Detrital Zircon from the Wuzhiling Formation at the Dengfeng Area

The systematic LA-ICP-MS U-Pb dating and in-situ Lu-Hf isotope analyses of the detrital zircons from both two mica quartz schist and quartzite in the Wuzhiling Formation of Songshan Group in the Dengfeng area provide new constraints on the Archean crustal growth and reconstruction of the southern margin of the North China Craton (NCC). The study shows that most detrital zircons from the Wuzhiling Formation are euhedral-subhedral, and the oscillatory zoning in CL images and high ratios of Th/U (0.07-1.87) indicate that they are of magmatic origin. The two mica quartz schist and quartzite of Wuzhiling Formation have similar U-Pb ages and in-situ Hf isotopic compositions. Specifically, their 207Pb/206Pb ages are varying from 2879 to 2027 Ma and from 3346 to 1903 Ma, with peak ages at 2524 Ma and 2528 Ma, respectively. Additionally, the detrital zircons with age of ca. 2.5 Ga from the Wuzhiling Formation mostly have positive εHf(t) values (+0.10 to +9.22) with corresponding tDM2 C ages of 3028-2453 Ma except four zircon grains with negative values (-1.68 to -0.03) and tDM2 C ages of 3132-3032 Ma. Combining with the previous results in the adjacent areas, it can be inferred that the Songshan Group was deposited in the Late Paleoproterozoic while the provenance of the Wuzhiling Formation are mainly the ca. 2.5 Ga crystalline basement material with juvenile crustal properties in the southern NCC. In conclusion, the Archean crustal growth at the southern margin of NCC constitutes both of juvenile crustal increment and reworking of the ancient crust. © 2018, Science Press. All right reserved.