| The Shouxian Formation is a set of Precambrian clastic strata widely developed in the southeast part of the North China Craton, and the understanding of its deposition time has been divergent for a long time. Since there are abundant macroalgae fossils in the upper and lower adjacent strata of Shouxian Formation, it is of great significance to identify the lithology, sedimentary environment, timing and sources for understanding the late Precambrian paleogeography, biostratigraphic sequence correlation and sedimentary tectonic evolution. In this study, the outcrop locations, lithologies and sequence characteristics of the Shouxian Formation from such late Precambrian successions in the Huainan area were determined through detailed field investigation. Five rock samples were collected for microscopic observation, grain size analysis, and LA-ICP-MS detrital zircon U-Pb dating, in order to analyze the depositional environment, time constraints and sediment source characteristics of the Shouxian Formation. The study indicates that the Shouxian Formation is a set of medium to thick-bedded calcareous fine clastic rocks, occasionally interbedded with medium to thin-bedded muddy layers. The grain size analysis results show that it belongs to the transitional type between fine sandstone and coarse siltstone, and the grain size composition is dominated by suspended load components, less saltation load components, with high maturity and weak depositional hydrodynamic conditions. Combined with the appearance of glauconite minerals and the calculation results of Sahu discrimination function, it is inferred that the sedimentation is in a shelf environment between the littoral zone and the transitional zone. The youngest single-grain detrital zircon ages of the five samples are 962±25, 963±31, 954±25, 952±24, and 976±26 Ma, respectively. The weighted average age of the youngest set of detrital zircon ages from the whole samples of Shouxian Formation within the Huainan area is 953±9 Ma. Combined with the intrusive age of the mafic sill complexes of 943 to 876 Ma in the Xuzhou-Huaibei area, which intrudes into the equivalent stratigraphic sequence, the depositional time of the Shouxian Formation is constrained to be between 953 and 943 Ma. The detrital zircon age spectrum of the Shouxian Formation shows a gradual increase in the number of detrital zircons since 1.8 Ga, and it is rich in detrital zircons of 1.2 to 1.0 Ga. A comprehensive analysis suggests that the main sediment source of the Shouxian Formation should come from a landmass or landmass groups that were once connected outside the North China Craton, but it cannot be ruled out that the interior of the North China Craton could also serve as a secondary source area. |