The supracrustal rocks are widely developed in the Lüliang area of Shanxi Province. The Lanhe Group, as an important part, is outcropped in both north and south sides of the Lanxian County, which mainly composed of clastic rocks, carbonatite with minor meta-basalts and is an ideal object to probe the sedimentary characteristics, formation age and relationship with other supracrustal rocks due to the greenschist facies metomorphism and primary sedimentary structure preserved in some calsitic rocks. The LA-ICP-MS U-Pb dating of detrital zircons from three samples yield the youngest peak age of ～2.2 Ga in their lower sequence. Combined with their metamorphism similar to those occured in the Lvliang area at 1.87 Ga, the forming age of the Lanhe Group can be limited between 2.2 Ga and 1.87 Ga. Their U-Pb age spectrum is characterized by a main peak at ～2.2 Ga and smaller peaks at ～2.3 Ga and the end of Neoarchean, suggesting that they are mainly derived from the Paleoproterozoic continental provenance other than Archaean crust. The Hf isotopic features of detrital zicons with the ags of ～2.2 Ga are much consistent with the temporal granitoids related to island arc setting. In addtion, their sedimentary assemblages indicate an active sedimentary enviroment. All suggest that Lanhe Group is formed in a arc-related basin in the active continental margin. The sedimentary sequences of the Qingyangshuwan and Bailongshan Formations of the lower part of Yejishan Group are well compared with those of the Lanhe Group, and both are deposited at ～2.2 Ga. Therefore, the lower part of the Yejishan group, as Lanhe Group, can be considered to be diposited in the arc-related basin in the continental margin. Both represented likely the transformation of sedimentaru facies at the same period. While the sedimentary sequeces of Chengdaogou Formation in the upper part of the Yejishan Group is similar to the sequenc of the Heichashan Group with molasse deposits in a foreland basin associated with the collision between continental blocks. Consequently, the sedimentary evolution of the Lanhe Group, Yejishan Group and Heichashan Group in the Lüliang area reveal the tectonic eviolution from active continental margin at ～2.2 Ga and translated into the continent-continent collision at ～1.85 Ga along the Trans-North China orogen of North China Craton.
Hu Yuhua Zhang Chengli Zhao Jiao Guo Xiaojun Liu Xinyu Wang Lu Liu Bingxu. Deposition age and sedimentary setting of the Lanhe Groups in Lüliang area of Shanxi Province: Evidences from detrital zircon U-Pb dating and their Hf isotopes[J]. Chinese Journal of Geology, 2017, 52(4): 1195-1219.